JP2005084584A - Positive resist composition and method for forming pattern by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive resist composition suitable when an exposure light source at ≤200 nm, in particular, F<SB>2</SB>excimer laser light (at 157 nm) is used, specifically, a positive resist composition having sufficient transmittance when a light source at 157 nm is used and having excellent properties of resolution, sensitivity, development defect and solubility contrast, and to provide a method for forming a pattern by using the composition. <P>SOLUTION: The positive resist composition contains: (A) a resin having at least one kind of specified repeating unit of a specified structure and having a group the solubility of which with an alkaline developing solution is increased by the effect of an acid; and (B) a compound which generates an acid by the effect of active rays or radiation. The method for forming a pattern is carried out by using the composition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a positive resist composition suitably used in microlithography processes such as the production of VLSI and high-capacity microchips, and other photofabrication processes, and a pattern forming method using the same.

  Integrated circuits have been increasingly integrated, and in manufacturing semiconductor substrates such as VLSI, processing of ultrafine patterns having a line width of less than a quarter micron has been required. As one of means for miniaturizing a pattern, it is known to shorten the wavelength of an exposure light source used in forming a resist pattern.

  For example, in the production of a semiconductor device having a degree of integration up to 64 Mbits, i-line (365 nm) of a high-pressure mercury lamp has been used as a light source until now. As a positive resist corresponding to this light source, a number of compositions containing a novolak resin and a naphthoquinonediazide compound as a photosensitive material have been developed, and have achieved sufficient results in processing line widths of up to about 0.3 μm. . Further, in the manufacture of a semiconductor device having a degree of integration of 256 Mbits or more, KrF excimer laser light (248 nm) has been adopted as an exposure light source instead of i-line.

  In addition, for the purpose of manufacturing semiconductors with a degree of integration of 1 Gbit or more, the use of ArF excimer laser light (193 nm), which is a light source with a shorter wavelength in recent years, and F2 excimer laser light (to form a pattern of 0.1 μm or less) 157 nm) is under consideration.

  In accordance with the shortening of the wavelength of these light sources, the constituent components of the resist material and the compound structure thereof have also changed greatly.

  As a resist composition for exposure with KrF excimer laser light, a resin mainly composed of poly (hydroxystyrene) having a low absorption in the 248 nm region and protected with an acid-decomposable group is used as a main component. Compositions combining so-called generated compounds (photoacid generators), so-called chemically amplified resists, have been developed.

  Further, as a resist composition for ArF excimer laser light (193 nm) exposure, there is a chemically amplified resist using an acid-decomposable resin in which an alicyclic structure having no absorption at 193 nm is introduced into the main chain or side chain of a polymer. It has been developed.

For the F ₂ excimer laser light (157 nm), the above alicyclic resin also has a large absorption in the 157 nm region, and it has been found that this is insufficient to obtain the desired pattern of 0.1 μm or less. In contrast, non-patent document 1 (Proc.SPIE.Vol.3678.13 (1999)) reports that a resin having a fluorine atom (perfluoro structure) introduced has sufficient transparency at 157 nm, and effective fluorine. Non-Patent Document 2 (Proc. SPIE. Vol. 3999. 330 (2000)), Non-Patent Document 3 (Proc. SPIE. Vol. 3999.357 (2000)), Non-Patent Document 4 (Proc. SPIE. Vol.3999. 365 (2000)), Patent Document 1 (International Publication No. 00/17712 pamphlet), Patent Document 2 (International Publication No. 00/67072 pamphlet), Patent Document 3 (Japanese Patent Laid-Open No. 2001-133879). Publication)) and contains fluorine-containing resin Study of Reshisuto composition have been made.

However, the resist composition containing a fluororesin for F ₂ excimer laser light exposure has been desired to be further improved in terms of limit resolution, sensitivity, development defects, and dissolution contrast.

International Optical Engineering Bulletin (Proc.SPIE.) Vol.3678. P.13. (1999) International Optical Engineering Bulletin (Proc.SPIE.) Vol.3999. 330. (2000) International Optical Engineering Bulletin (Proc.SPIE.) Vol.3999. 357. (2000) International Optical Engineering Bulletin (Proc.SPIE.) Vol.3999. 365. (2000) WO-00 / 17712 pamphlet WO-00 / 67072 pamphlet Japanese Patent Laid-Open No. 2001-133799

Accordingly, an object of the present invention is to provide a positive resist composition suitable for use with an exposure light source of 200 nm or less, particularly F ₂ excimer laser light (157 nm), and a pattern forming method using the same. Is to provide a positive resist composition that exhibits sufficient transparency when using a light source of 157 nm and is excellent in limiting resolution, sensitivity, development defect, and dissolution contrast, and a pattern forming method using the same.

  As a result of intensive investigations while paying attention to the above characteristics, the present inventors have found that the object of the present invention can be achieved by using the following specific composition, and have reached the present invention.

  That is, the present invention has the following configuration.

(1) (A) a resin having at least one repeating unit represented by the following general formula (I), which decomposes by the action of an acid and increases its solubility in an alkaline developer, and (B) the action of actinic rays or radiation A positive resist composition comprising a compound capable of generating an acid by.

In general formula (I),
R ₁ and R ₂ each independently represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group. However, at least one of R ₁ and R ₂ represents a fluorine atom or an alkyl group having at least one fluorine atom.

R ₃ represents a hydrogen atom, a cyano group or an alkyl group.

  X represents an alkali-soluble group, a group having an alkali-soluble group protected with an acid-decomposable group, or a group having an alkali-soluble group protected with a non-acid-decomposable group.

L ₁ represents a single bond or a divalent linking group.

L ₂ represents a (n + 1) -valent linking group.

  n represents an integer of 1 to 4.

  (2) The positive resist composition as described in (1), wherein X in the general formula (I) is represented by the following general formula (A).

In general formula (A),
R _{31 to} R ₃₆ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{31 to} R ₃₆ represents a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom.

  Y represents a hydrogen atom or an organic group.

L ₃ represents a single bond or a divalent linking group.

(3) The positive resist composition as described in (1) or (2), wherein L ₂ in the general formula (I) has an alicyclic structure.

(4) The positive resist composition as described in any one of (1) to (3), wherein R ₁ and R ₂ in the general formula (I) are both fluorine atoms.

(5) The positive resist composition as described in any one of (1) to (4), wherein L ₁ in the general formula (I) is a single bond or an alkylene group having 1 to 4 carbon atoms. Stuff.

  (6) A pattern forming method comprising the steps of: forming a resist film from the positive resist composition according to any one of (1) to (5); and exposing and developing the resist film.

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

  (7) The positive resist composition as described in (1), wherein the general formula (I) is represented by the following general formula (Ia).

In general formula (Ia),
R ₃ and n have the same meanings as R ₃ and n in formula (I).

R ₃₁ to R _36, Y and L ₃ has the same meaning as R ₃₁ to R _36, Y and L ₃ in the general formula (A).

  m represents an integer of 0 to 4.

  x represents 0 or 1;

  Rz represents a hydroxyl group, an alkoxy group, a halogen atom, a cyano group or an alkyl group.

  p represents an integer of 0 to 7.

  (8) The resin of component (A) further has at least one type of repeating unit selected from the following general formulas (II) to (IX): (1) to (5) and (7 The positive resist composition according to any one of the above.

In general formulas (II) to (IX),
R ₅ represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group.

R ₁₁ represents a hydrogen atom, a hydroxyl group, a halogen atom, a cyano group, an alkoxy group, an acyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group.

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.

  Z each independently represents a hydrogen atom or an organic group.

  k represents an integer of 1 to 5.

  k 'represents an integer of 0 to 4.

  When there are a plurality of Rb, each independently represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group.

A ₁ represents a single bond or a divalent linking group.

  n ′ represents 0 or 1.

  na represents an integer of 0 to 7.

Rc _{1 to} Rc ₃ each independently represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group.

  Ya represents a hydrogen atom or an organic group.

Ry _{1 to} Ry ₃ each independently represents a hydrogen atom, a fluorine atom, a base atom, a cyano group or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom.

Rx _{1 to} Rx ₃ each independently represents a hydrogen atom, a fluorine atom, a base atom, a cyano group or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom.

R _{61 to} R ₇₂ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{61 to} R ₆₆ is a fluorine atom, and at least one of R _{67 to} R ₇₂ is a fluorine atom.

Z ₁ represents a phenylene group, a cyclohexylene group, an adamantane residue or a norbornane residue.

L ₄ represents a single bond or a divalent linking group.

  q represents 0 or 1;

Ra _{1 to} Ra ₃ each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, an alkyl group, an aryl group, an alkoxy group or an aralkyl group.

  m represents 0 or 1.

Ra _{4 to} Ra ₆ each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, an alkyl group, an aryl group, an alkoxy group or an aralkyl group.

L ₅ represents a single bond or a divalent linking group.

(9) The positive resist composition as described in any one of (1) to (5) and (7) to (8), further comprising (X) a non-polymer type dissolution inhibitor.

(10) The positive resist composition as described in any one of (1) to (5) and (7) to (9), further comprising (E) an organic basic compound.

(11) The positive resist composition as described in any one of (1) to (5) and (7) to (10), further comprising (D) a surfactant.

(12) As a compound of component (B),
(B1) The positive resist composition as described in any one of (1) to (5) and (7) to (11), which contains a compound that generates an organic sulfonic acid by the action of actinic rays or radiation Stuff.

(13) As a compound of component (B1),
(B1a) a compound that generates an organic sulfonic acid having at least one fluorine atom by the action of active light or radiation, and (B1b) a compound that generates an organic sulfonic acid having no fluorine atom by the action of active light or radiation. (1) The positive resist composition as described in (12), which contains one or more of each.

(14) As a compound of component (B),
The positive resist composition as described in (12) or (13), further comprising (B2) a compound capable of generating a carboxylic acid by the action of actinic rays or radiation.

  According to the present invention, a positive resist composition exhibiting sufficient transparency at 200 nm or less, particularly at a short wavelength of F2 excimer laser light (157 nm), and excellent in resolving power, sensitivity, development defect, and dissolution contrast, and a pattern using the same A forming method can be provided.

  Hereinafter, the present invention will be described in detail.

  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) A resin having at least one repeating unit represented by the following general formula (I), which decomposes by the action of an acid and increases the solubility in an alkali developer. The positive resist composition of the present invention comprises: A resin (hereinafter also referred to as “acid-decomposable resin (A)”) that has at least one repeating unit represented by the following general formula (I) and that is decomposed by the action of an acid to increase the solubility in an alkaline developer. contains.

In general formula (I),
R ₁ and R ₂ each independently represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group. However, at least one of R ₁ and R ₂ represents a fluorine atom or an alkyl group having at least one fluorine atom.

R ₃ represents a hydrogen atom, a cyano group or an alkyl group.

  X represents an alkali-soluble group, a group having an alkali-soluble group protected with an acid-decomposable group, or a group having an alkali-soluble group protected with a non-acid-decomposable group.

L ₁ represents a single bond or a divalent linking group.

L ₂ represents a (n + 1) -valent linking group.

  n represents an integer of 1 to 4.

Examples of the halogen atom for R ₁ and R ₂ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The alkyl group represented by R _{1 to} R ₃ is preferably an alkyl group having 1 to 5 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, or a t-butyl group. Etc. can be mentioned preferably. The alkyl groups of R _{1 to} R ₃ include those having no substituent and those having a substituent. Examples of the substituent that the alkyl group represented by R _{1 to} R ₃ may have include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom), a hydroxyl group, and a cyano group.

As the alkyl group having at least one fluorine atom of R ₁ and R ₂ , the above alkyl group in which at least one hydrogen atom is substituted with a fluorine atom is preferable. For example, a perfluoromethyl group, a perfluoroethyl group, a perfluoroethyl group, A fluoropropyl group etc. can be mentioned.

R ₁ and R ₂ are preferably both fluorine atoms.

  The group having an alkali-soluble group, a group obtained by protecting an alkali-soluble group with an acid-decomposable group, or a group obtained by protecting an alkali-soluble group with a non-acid-decomposable group is preferably represented by the following general formula (A).

In general formula (A),
R _{31 to} R ₃₆ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{31 to} R ₃₆ represents a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom.

  Y represents a hydrogen atom or an organic group.

L ₃ represents a single bond or a divalent linking group.

_{Incidentally, -C (R 31 R 32 R} 33) refers to a group in which each of the groups represented by R ₃₁ to R ₃₃ on the carbon atom attached by a single bond. The same shall apply hereinafter.

Examples of the alkyl group for R _{31 to} R ₃₆ include the same alkyl groups as those for R _{1 to} R ₃ .

Examples of the alkyl group in which at least one hydrogen atom of R _{31 to} R ₃₆ is substituted with a fluorine atom include those similar to the alkyl group having at least one fluorine atom of R ₁ and R ₂ .

All of R _{31 to} R ₃₆ are preferably fluorine atoms.

  In the general formula (A), when Y is a hydrogen atom, the —OY group becomes an alkali-soluble group.

  Examples of the organic group for Y include an acid-decomposable group that is released from an oxygen atom by the action of an acid and a non-acid-decomposable group that is not released from an oxygen atom even when an acid is applied.

  When Y is an acid-decomposable group, the —OY group is a group obtained by protecting an alkali-soluble group with an acid-decomposable group, and when Y is a non-acid-decomposable group, the —OY group is a non-alkali-soluble group. A group protected with an acid-decomposable group.

The acid-decomposable group for Y is not limited as long as the hydroxyl group is formed by elimination from an oxygen atom by the action of an acid and the solubility in an alkali developer is increased, but -C (R _11a ) ( A group represented by R _12a ) (R _13a ), —C (R _14a ) (R _15a ) (OR _16a ) or —CO—O—C (R _11a ) (R _12a ) (R _13a ) is preferred.

In addition, -C (R _<11a> ) (R _<12a> ) (R _<13a> ) means the group which each group represented by R _{< 11a} > -R < _13a > couple | bonds with the carbon atom by the single bond. The same shall apply hereinafter.

R _{11a to} R _13a each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. R _14a and R _15a each independently represents a hydrogen atom or an alkyl group. R _16a represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. Two of R _11a , R _12a and R _13a , or two of R _14a , R _15a and R _16a may combine to form a ring.

As the alkyl group for R _{11a to} R _13a , R _14a , R _15a and R _16a , an alkyl group having 1 to 8 carbon atoms is preferable. For example, a methyl group, an ethyl group, a propyl group, an n-butyl group, sec- A butyl group, a hexyl group, a 2-ethylhexyl group, an octyl group, etc. can be mentioned.

The cycloalkyl group for R _{11a to} R _13a and R _16a may be monocyclic or polycyclic. The monocyclic type is preferably a cycloalkyl group having 3 to 8 carbon atoms, and examples thereof include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclobutyl group, and a cyclooctyl group. As the polycyclic type, a cycloalkyl group having 6 to 20 carbon atoms is preferable. For example, an adamantyl group, norbornyl group, isobornyl group, camphanyl group, dicyclopentyl group, α-pinel group, tricyclodecanyl group, tetocyclo A dodecyl group, an androstanyl group, etc. can be mentioned. A part of carbon atoms in the cycloalkyl group may be substituted with a hetero atom such as an oxygen atom.

The aryl group of R _{11a to} R _13a and R _16a is preferably an aryl group having 6 to 10 carbon atoms, such as a phenyl group, tolyl group, dimethylphenyl group, 2,4,6-trimethylphenyl group, naphthyl group. , Anthryl group, 9,10-dimethoxyanthryl group and the like.

As the aralkyl group of R _{11a to} R _13a and R _16a, an aralkyl group having 7 to 12 carbon atoms is preferable, and examples thereof include a benzyl group, a phenethyl group, and a naphthylmethyl group.

The alkenyl group of R _{11a to} R _13a and R _16a is preferably an alkenyl group having 2 to 8 carbon atoms, and examples thereof include a vinyl group, an allyl group, a butenyl group, and a cyclohexenyl group.

The substituents that R _{11a to} R _13a , R _14a , R _15a , and R _16a may have include an alkyl group, a cycloalkyl group, an aryl group, an amino group, an amide group, a ureido group, a urethane group, and a hydroxy group. Carboxy group, halogen atom, alkoxy group, thioether group, acyl group, acyloxy group, alkoxycarbonyl group, cyano group, nitro group and the like.

  The non-acid-decomposable group for Y is an organic group that does not leave an oxygen atom even when an acid acts. For example, an alkyl group or cycloalkyl that does not leave an oxygen atom even when an acid acts. Group, aryl group, aralkyl group, alkoxy group, alkoxycarbonyl group, amide group, cyano group and the like. The alkyl group is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, for example, methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group, hexyl group, 2-ethylhexyl group. And octyl group. The cycloalkyl group is preferably a cycloalkyl group having 3 to 10 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclohexyl group, an adamantyl group, and a norbornyl group. The aryl group is preferably an aryl group having 6 to 14 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and an anthracenyl group. The aralkyl group is preferably an aralkyl group having 6 to 12 carbon atoms, and examples thereof include a benzyl group, a phenethyl group, and a cumyl group. The alkoxy group in the alkoxy group and the alkoxycarbonyl group is preferably an alkoxy group having 1 to 5 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, and an isobutoxy group.

The divalent linking group of L ₃ is a single group selected from the group consisting of an alkylene group, an arylene 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 the combination of 2 or more groups can be mentioned. The alkylene group is preferably an alkylene group having 1 to 8 carbon atoms such as a methylene group, an ethylene group, a propylene group, a butylene group, a hexylene group and an octylene group. The arylene group is preferably an arylene group having 6 to 15 carbon atoms such as a phenylene group, a tolylene group and a naphthylene group.

L ₃ is preferably a single bond or an alkylene group having 1 to 4 carbon atoms.

Examples of the divalent linking group for L _{1 in} the general formula (I) include the same divalent linking groups for L _{3 in} the general formula (A).

L ₁ is preferably a single bond or an alkylene group having 1 to 4 carbon atoms.

The (n + 1) -valent linking group of L ₂ preferably has an alicyclic structure such as monocyclo, bicyclo, tricyclo, or tetracyclo. The carbon number is preferably 6-30, and more preferably 7-25. Preferred examples of the (n + 1) -valent linking group include, for example, an adamantane residue (residue obtained by removing (n + 1) hydrogen atoms from adamantane, the same shall apply hereinafter), a noradamantane residue, a cyclohexane residue, a decalin residue, A tricyclodecane residue, a tetracyclododecane residue, a norbornane residue, etc. can be mentioned. More preferable examples of the (n + 1) -valent linking group include an adamantane residue, a norbornane residue, and a cyclohexane residue. In the (n + 1) -valent linking group, an alkylene group having 1 to 5 carbon atoms, a perfluoroalkylene group or the like may be further bonded to the alicyclic structure.

  The general formula (I) is preferably represented by the following general formula (Ia).

In general formula (Ia),
R ₃ and n have the same meanings as R ₃ and n in formula (I).

R ₃₁ to R _36, Y and L ₃ has the same meaning as R ₃₁ to R _36, Y and L ₃ in the general formula (A).

  m represents an integer of 0 to 4.

  x represents 0 or 1;

  Rz represents a hydroxyl group, an alkoxy group, a halogen atom, a cyano group or an alkyl group.

  p represents an integer of 0 to 7.

  Examples of the halogen atom for Rz in the general formula (Ia) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  The alkyl group in the alkyl group and alkoxy group of Rz is preferably an alkyl group having 1 to 5 carbon atoms, specifically, methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group, A t-butyl group etc. can be mentioned preferably. The alkyl group includes those having no substituent and those having a substituent. Examples of the substituent that the alkyl group may have include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom), a hydroxyl group, and a cyano group.

  Hereinafter, although the specific example of the repeating unit represented by general formula (I) or (IA) is given, this invention is not limited to this.

  The acid-decomposable resin (A) preferably further has at least one repeating unit selected from the following general formulas (II) to (IX).

In general formulas (II) to (IX),
R ₅ represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group.

R ₁₁ represents a hydrogen atom, a hydroxyl group, a halogen atom, a cyano group, an alkoxy group, an acyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group.

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.

  Z each independently represents a hydrogen atom or an organic group.

  k represents an integer of 1 to 5.

  k 'represents an integer of 0 to 4.

  When there are a plurality of Rb, each independently represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group.

A ₁ represents a single bond or a divalent linking group.

  n ′ represents 0 or 1.

  na represents an integer of 0 to 7.

Rc _{1 to} Rc ₃ each independently represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group.

  Ya represents a hydrogen atom or an organic group.

Ry _{1 to} Ry ₃ each independently represents a hydrogen atom, a fluorine atom, a base atom, a cyano group or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom.

Rx _{1 to} Rx ₃ each independently represents a hydrogen atom, a fluorine atom, a base atom, a cyano group or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom.

R _{61 to} R ₇₂ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{61 to} R ₆₆ is a fluorine atom, and at least one of R _{67 to} R ₇₂ is a fluorine atom.

Z ₁ represents a phenylene group, a cyclohexylene group, an adamantane residue or a norbornane residue.

L ₄ represents a single bond or a divalent linking group.

  q represents 0 or 1;

Ra _{1 to} Ra ₃ each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, an alkyl group, an aryl group, an alkoxy group or an aralkyl group.

  m represents 0 or 1.

Ra _{4 to} Ra ₆ each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, an alkyl group, an aryl group, an alkoxy group or an aralkyl group.

L ₅ represents a single bond or a divalent linking group.

The halogen atoms of R ₅ , R ₁₁ , Rb, Rc _{1 to} Rc ₃ , and Ra _{1 to} Ra _{6 in} the general formulas (II) to (IX) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. be able to.

_{R 5, R 11, Rb,} Rc 1 ~Rc 3, in the alkyl group in the alkoxy group of Ra ₁ alkyl group and R ₁₁ in to Ra _6, Ra ₁ to Ra ₆ is 1-8C alkyl group having a carbon Specifically, a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, a hexyl group, a 2-ethylhexyl group, an octyl group, and the like can be given.

The alkyl group in which at least one hydrogen atom of Ry _{1 to} Ry ₃ and Rx _{1 to} Rx ₃ is substituted with a fluorine atom is preferably the above alkyl group in which at least one hydrogen atom is substituted with a fluorine atom. Examples thereof include a methyl group, a perfluoroethyl group, and a perfluoropropyl group.

The cycloalkyl group represented by R ₁₁ may be monocyclic or polycyclic. The monocyclic type has 3 to 8 carbon atoms, and preferred examples include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. The polycyclic type has 6 to 20 carbon atoms, such as an adamantyl group, norbornyl group, isobornyl group, campanyl group, dicyclopentyl group, a-pinel group, tricyclodecanyl group, tetocyclododecyl group, An androstanyl group etc. can be mentioned preferably. However, the carbon atom in the monocyclic or polycyclic cycloalkyl group may be substituted with a heteroatom such as an oxygen atom.

The aryl group of R ₁₁ and Ra _{1 to} Ra ₆ is preferably an aryl group having 6 to 15 carbon atoms, and specific examples thereof include a phenyl group, a naphthyl group, and an anthryl group.

The acyl group of R ₁₁ is preferably an acyl group having 1 to 10 carbon atoms, and specific examples include formyl group, acetyl group, propanoyl group, butanoyl group, pivaloyl group, octanoyl group and benzoyl group. .

The aralkyl group of R ₁₁ and Ra _{1 to} Ra ₆ is preferably an aralkyl group having 7 to 12 carbon atoms, and specific examples include a benzyl group, a phenethyl group, and a naphthylmethyl group.

The alkenyl group of R ₁₁ is preferably an alkenyl group having 2 to 8 carbon atoms, and specific examples include a vinyl group, an allyl group, a butenyl group, and a cyclohexenyl group.

  The above alkyl group, cycloalkyl group, aryl group, aralkyl group, alkenyl group, acyl group and the like may or may not have a substituent. Examples of the substituent that the alkyl group, cycloalkyl group, aryl group, aralkyl group, alkenyl group, acyl group and the like may have include an alkyl group, a cycloalkyl group, an aryl group, an amino group, an amide group, and a ureido group. Having active hydrogen such as a group, urethane group, hydroxyl group, carboxyl group, halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), alkoxy group (methoxy group, ethoxy group, propoxy group, butoxy group, etc.) ), Thioether group, acyl group (acetyl group, propanoyl group, benzoyl group, etc.), acyloxy group (acetoxy group, propanoyloxy group, benzoyloxy group, etc.), alkoxycarbonyl group (methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl) Group), cyano group, nitro group, etc.

  Here, examples of the alkyl group, cycloalkyl group, and aryl group include those described above. The alkyl group may be further substituted with a fluorine atom or a cycloalkyl group.

R _{50 to} R ₅₅ in the general formulas (II) to (IX) are the same as R _{31 to} R ₃₆ in the general formula (A).

R _{50 to} R ₅₅ are preferably fluorine atoms.

  Z is the same as Y in the general formula (A).

The divalent linking group of A ₁ , L ₄ and L _{5 is the same as} the divalent linking group of L _{3 in} the general formula (A).

Examples of the alkyl group of R _{61 to} R ₇₂ include the same alkyl groups as R _{31 to} R _{36 in} the general formula (A).

R _{61 to} R ₇₂ are preferably fluorine atoms.

  In the general formulas (II) to (IX), when Ya is a hydrogen atom, the —COOYa group becomes an alkali-soluble group.

  Examples of the organic group of Ya include an acid-decomposable group that is eliminated from an oxygen atom by the action of an acid and a non-acid-decomposable group that is not eliminated from an oxygen atom even when an acid acts.

The acid-decomposable group of Ya is not limited as long as the carboxyl group is formed by elimination from an oxygen atom by the action of an acid and the solubility in an alkali developer is increased, but -C (R _11b ) A group represented by (R _12b ) (R _13b ) or —C (R _14b ) (R _15b ) (OR _16b ) is preferred.

R _{11b to} R _13b each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. R _14b and R _15b each independently represents a hydrogen atom or an alkyl group. R _16b represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. Two of R _11b , R _12b and R _13b , or two of R _14b , R _15b and R _16b may be bonded to form a ring.

As the alkyl group for R _{11b to} R _13b , R _14b , R _15b , and R _16b , an alkyl group having 1 to 8 carbon atoms is preferable. A butyl group, a hexyl group, a 2-ethylhexyl group, an octyl group, etc. can be mentioned.

The cycloalkyl group for R _{11b to} R _13b and R _16b may be monocyclic or polycyclic. The monocyclic type is preferably a cycloalkyl group having 3 to 8 carbon atoms, and examples thereof include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclobutyl group, and a cyclooctyl group. As the polycyclic type, a cycloalkyl group having 6 to 20 carbon atoms is preferable. For example, an adamantyl group, norbornyl group, isobornyl group, camphanyl group, dicyclopentyl group, α-pinel group, tricyclodecanyl group, tetocyclo A dodecyl group, an androstanyl group, etc. can be mentioned. A part of carbon atoms in the cycloalkyl group may be substituted with a hetero atom such as an oxygen atom.

The aryl group of R _{11b to} R _13b and R _16b is preferably an aryl group having 6 to 10 carbon atoms, such as a phenyl group, tolyl group, dimethylphenyl group, 2,4,6-trimethylphenyl group, naphthyl group. , Anthryl group, 9,10-dimethoxyanthryl group and the like.

The aralkyl group of R _{11b to} R _13b and R _16b is preferably an aralkyl group having 7 to 12 carbon atoms, and examples thereof include a benzyl group, a phenethyl group, and a naphthylmethyl group.

The alkenyl group of R _{11b to} R _13b and R _16b is preferably an alkenyl group having 2 to 8 carbon atoms, and examples thereof include a vinyl group, an allyl group, a butenyl group, and a cyclohexenyl group.

The substituents that R _{11b to} R _13b , R _14b , R _15b , and R _16b may have include an alkyl group, a cycloalkyl group, an aryl group, an amino group, an amide group, a ureido group, a urethane group, and a hydroxy group. Carboxy group, halogen atom, alkoxy group, thioether group, acyl group, acyloxy group, alkoxycarbonyl group, cyano group, nitro group and the like.

  The non-acid-decomposable group for Ya is an organic group that does not leave an oxygen atom even when an acid acts. For example, an alkyl group or a cycloalkyl that does not leave an oxygen atom even when an acid acts. Group, aryl group, aralkyl group, alkoxy group, alkoxycarbonyl group, amide group, cyano group and the like. The alkyl group is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, for example, methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group, hexyl group, 2-ethylhexyl group. And octyl group. The cycloalkyl group is preferably a cycloalkyl group having 3 to 10 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclohexyl group, and an adamantyl group. The aryl group is preferably an aryl group having 6 to 14 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and an anthracenyl group. The aralkyl group is preferably an aralkyl group having 6 to 12 carbon atoms, and examples thereof include a benzyl group, a phenethyl group, and a cumyl group. The alkoxy group in the alkoxy group and the alkoxycarbonyl group is preferably an alkoxy group having 1 to 5 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, and an isobutoxy group.

  Hereinafter, although the specific example of the repeating unit represented by general formula (II)-(IX) is given, this invention is not limited to this.

  The acid-decomposable resin (A) may further have at least one repeating unit represented by the following general formulas (FI) to (FIII).

In general formulas (FI) to (FIII),
Re ₀ and Re ₁ may be the same or different and each represents a hydrogen atom, a fluorine atom, an alkyl group, a cycloalkyl group, or an aryl group.

Re _{2 to} Re ₄ may be the same or different and each represents an alkyl group, a cycloalkyl group, or an aryl group.

Further, Re ₀ and Re ₁ , Re ₀ and Re ₂ , Re ₃ and Re ₄ may combine to form a ring.

  Examples of the alkyl group include an alkyl group having 1 to 8 carbon atoms, and specifically include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, and a hexyl group. , 2-ethylhexyl group and octyl group can be preferably exemplified.

  The cycloalkyl group may be monocyclic or polycyclic. The monocyclic type has 3 to 8 carbon atoms, and preferred examples include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. The polycyclic type has 6 to 20 carbon atoms, such as an adamantyl group, norbornyl group, isobornyl group, campanyl group, dicyclopentyl group, a-pinel group, tricyclodecanyl group, tetocyclododecyl group, An androstanyl group etc. can be mentioned preferably. However, the carbon atom in the monocyclic or polycyclic cycloalkyl group may be substituted with a heteroatom such as an oxygen atom.

  As the aryl group, for example, an aryl group having 6 to 15 carbon atoms, specifically, phenyl group, tolyl group, dimethylphenyl group, 2,4,6-trimethylphenyl group, naphthyl group, anthryl group, Preferable examples include 9,10-dimethoxyanthryl group.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  The alkyl group, cycloalkyl group, aryl group and the like may not have a substituent or may have a substituent. Alkyl group, cycloalkyl group, aryl group, aralkyl group, alkenyl group, alkoxy group, alkoxymethyl group, acyl group, alkynyl group, alkoxycarbonyl group, alkylene group, alkenylene group, cycloalkylene group, arylene group, etc. Examples of the substituent which may be used include those having active hydrogen such as alkyl group, cycloalkyl group, aryl group, amino group, amide group, ureido group, urethane group, hydroxyl group and carboxyl group, and halogen atom (fluorine). Atom, chlorine atom, bromine atom, iodine atom), alkoxy group (methoxy group, ethoxy group, propoxy group, butoxy group, etc.), thioether group, acyl group (acetyl group, propanoyl group, benzoyl group, etc.), acyloxy group (acetoxy group) Group, propanoyloxy group, benzoyloxy Etc.), an alkoxycarbonyl group (methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group), a cyano group and a nitro group.

  Here, examples of the alkyl group, cycloalkyl group, and aryl group include those described above. The alkyl group may be further substituted with a fluorine atom or a cycloalkyl group.

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

  The acid-decomposable resin (A) may further have a repeating unit represented by the following general formula (FIV).

In general formula (FIV),
Ra ₃₂ , Ra ₃₃ , and Ra ₃₄ may be the same or different and have a hydrogen atom, a fluorine atom, an alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, an alkenyl group having a fluorine atom, or a fluorine atom. An aralkyl group, an aryl group having a fluorine atom, an alkoxy group having a fluorine atom, or a hydroxyalkyl group is represented. However, at least one of Ra ₃₂ , Ra ₃₃ and Ra ₃₄ is a group other than a hydrogen atom.

  n represents 0 or 1, and x, y, z represents an integer of 0 to 4.

The alkyl group having a fluorine atom of Ra ₃₂ , Ra ₃₃ , and Ra ₃₄ in formula (FIV) is an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom. Examples of the alkyl group include carbon A number of 1 to 8 alkyl groups, specifically, methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group, t-butyl group, hexyl group, 2-ethylhexyl group, octyl Preference is given to groups.

The cycloalkyl group having a fluorine atom of Ra ₃₂ , Ra ₃₃ , and Ra ₃₄ is a cycloalkyl group in which at least one hydrogen atom is substituted with a fluorine atom. The cycloalkyl group may be monocyclic, polycyclic It may be a mold. The monocyclic type has 3 to 8 carbon atoms, and preferred examples include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. The polycyclic type has 6 to 20 carbon atoms, such as an adamantyl group, norbornyl group, isobornyl group, campanyl group, dicyclopentyl group, a-pinel group, tricyclodecanyl group, tetocyclododecyl group, An androstanyl group etc. can be mentioned preferably. However, the carbon atom in the monocyclic or polycyclic cycloalkyl group may be substituted with a heteroatom such as an oxygen atom.

The aryl group having a fluorine atom of Ra ₃₂ , Ra ₃₃ , and Ra ₃₄ is an aryl group in which at least one hydrogen atom is substituted with a fluorine atom. As the aryl group, for example, an aryl group having 6 to 15 carbon atoms Specifically, a phenyl group, a tolyl group, a dimethylphenyl group, a 2,4,6-trimethylphenyl group, a naphthyl group, an anthryl group, a 9,10-dimethoxyanthryl group and the like can be preferably exemplified. .

The aralkyl group having a fluorine atom of Ra ₃₂ , Ra ₃₃ , and Ra ₃₄ is an aralkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and examples of the aralkyl group include an aralkyl group having 7 to 12 carbon atoms. Specifically, preferred examples include benzyl group, phenethyl group, naphthylmethyl group and the like.

The alkenyl group having a fluorine atom of Ra ₃₂ , Ra ₃₃ , and Ra ₃₄ is an alkenyl group in which at least one hydrogen atom is substituted with a fluorine atom, and examples of the alkenyl group include alkenyl groups having 2 to 8 carbon atoms. Specifically, a vinyl group, an allyl group, a butenyl group, and a cyclohexenyl group can be preferably exemplified.

The alkoxy group having a fluorine atom of Ra ₃₂ , Ra ₃₃ , and Ra ₃₄ is an alkoxy group in which at least one hydrogen atom is substituted with a fluorine atom, and examples of the alkyl group in the alkoxy group include the above alkyl groups. be able to.

Examples of the alkyl group in the hydroxyalkyl group of Ra ₃₂ , Ra ₃₃ and Ra ₃₄ include the above alkyl groups.

  The alkyl group and the like include those that do not have a substituent and those that have a substituent.

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

  The acid-decomposable resin (A) may further have a repeating unit represented by the following general formula (FV).

In general formula (FV),
R ₄₁ represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group.

R ₄₂ to R ₄₇ each independently represent a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{42 to} R ₄₇ represents a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom.

Y ₆ represents a hydrogen atom or an organic group.

When there are a plurality of Y _{6 and} R _{42 to} R ₄₇ , they may be the same or different.

  t represents an integer of 1 to 5.

Examples of the halogen atom for R _{41 in} formula (FV) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The alkyl group for R _{41 is the same as} the alkyl group for R _{3 in} formula (I).

R _{42 to} R ₄₇ are the same as R _{31 to} R ₃₆ in the general formula (A).

Y ₆ is the same as Y in the general formula (A).

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

  Each of the repeating structural units represented by the above specific examples may be used alone or in combination.

  In addition to the above repeating structural unit, the acid-decomposable resin (A) may be copolymerized with other polymerizable monomers for the purpose of further improving the performance of the positive resist of the present invention.

  Examples of copolymerizable monomers that can be used include those shown below.

  For example, an addition polymerizable unsaturated bond selected from acrylic acid esters, acrylamides, methacrylic acid esters, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, styrenes, crotonic acid esters other than the above. A compound having one.

Specifically, for example, acrylic acid esters, for example, alkyl (the alkyl group preferably has 1 to 10 carbon atoms) acrylate (for example, methyl acrylate, ethyl acrylate, propyl acrylate, t-butyl acrylate) , Amyl acrylate, cyclohexyl acrylate, ethyl hexyl acrylate, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, trimethylol Propane monoacrylate, pentaerythritol monoacrylate, glycidyl acrylate, benzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, etc.) Rate (e.g., phenyl acrylate);
Methacrylic acid esters, for example, alkyl (the alkyl group preferably has 1 to 10 carbon atoms) methacrylate (for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, t-butyl methacrylate, amyl methacrylate, hexyl methacrylate) Cyclohexyl methacrylate, benzyl methacrylate, chlorobenzyl methacrylate, octyl methacrylate, 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 2,2-dimethyl-3-hydroxypropyl methacrylate, trimethylolpropane monomethacrylate, Pentaerythritol monomethacrylate, glycidyl methacrylate, Le furyl methacrylate, tetrahydrofurfuryl methacrylate), aryl methacrylates (e.g., phenyl methacrylate, cresyl methacrylate, naphthyl methacrylate, etc.);
Acrylamides, for example, acrylamide, N-alkyl acrylamide, (the alkyl group having 1 to 10 carbon atoms, for example, methyl group, ethyl group, propyl group, butyl group, t-butyl group, heptyl group, octyl Group, cyclohexyl group, benzyl group, hydroxyethyl group, benzyl group, etc.), N-arylacrylamide (as aryl group, for example, phenyl group, tolyl group, nitrophenyl group, naphthyl group, cyanophenyl group, hydroxyphenyl) Group, carboxyphenyl group, etc.), N, N-dialkylacrylamide (alkyl group having 1 to 10 carbon atoms, for example, methyl group, ethyl group, butyl group, isobutyl group, ethylhexyl group, cyclohexyl) Group, etc.), N, N-diaryla (Examples of the aryl group include phenyl group.) Riruamido, N- methyl -N- phenyl acrylamide, N- hydroxyethyl -N- methylacrylamide, etc. N-2- acetamidoethyl -N- acetyl acrylamide;
Methacrylamide, for example, methacrylamide, N-alkylmethacrylamide (the alkyl group has 1 to 10 carbon atoms, for example, methyl group, ethyl group, t-butyl group, ethylhexyl group, hydroxyethyl group, cyclohexyl Group, etc.), N-aryl methacrylamide (the aryl group includes phenyl group), N, N-dialkyl methacrylamide (the alkyl group includes ethyl group, propyl group, butyl group, etc.) ), N, N-diarylmethacrylamide (the aryl group includes phenyl group), N-hydroxyethyl-N-methylmethacrylamide, N-methyl-N-phenylmethacrylamide, N-ethyl-N -Phenylmethacrylamide and the like; allyl compounds such as allyl este Class (e.g., allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, etc.), and allyl oxyethanol;
Vinyl ethers such as alkyl vinyl ethers (eg hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethyl hexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl Vinyl ether, hydroxyethyl vinyl ether, diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, etc., vinyl aryl ethers (eg, vinyl phenyl ether, vinyl tolyl ether, vinyl chloropheny) Ether, vinyl 2,4-dichlorophenyl ether, vinyl naphthyl ether, vinyl anthranyl ether);
Vinyl esters such as vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, vinyl butoxyacetate, vinylphenyl Acetate, vinyl acetoacetate, vinyl lactate, vinyl-β-phenylbutyrate, vinyl cyclohexyl carboxylate, vinyl benzoate, vinyl salicylate, vinyl chlorobenzoate, vinyl tetrachlorobenzoate, vinyl naphthoate, etc .;
Styrenes such as styrene, alkyl styrene (for example, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, isopropyl styrene, butyl styrene, hexyl styrene, cyclohexyl styrene, decyl styrene, benzyl styrene, chloromethyl styrene, trifluoro Dimethyl styrene, ethoxymethyl styrene, acetoxymethyl styrene, etc.), alkoxy styrene (for example, methoxy styrene, 4-methoxy-3-methyl styrene, dimethoxy styrene, etc.), halogen styrene (for example, chloro styrene, dichloro styrene, trichloro styrene). , Tetrachlorostyrene, pentachlorostyrene, bromostyrene, dibromostyrene, iodostyrene, fluorostyrene, tri Ruorusuchiren, 2-bromo-4-trifluoromethyl styrene, 4-fluoro-3-trifluoromethyl styrene etc.), carboxy styrene, vinyl naphthalene;
Crotonic esters such as alkyl crotonic acid (eg butyl crotonate, hexyl crotonate, glycerol monocrotonate); dialkyl itaconates (eg dimethyl itaconate, diethyl itaconate, dibutyl itaconate); Examples thereof include dialkyl esters of acid or fumaric acid (for example, dimethyl maleate and dibutyl fumarate), maleic anhydride, maleimide, acrylonitrile, methacrylonitrile, maleilonitrile and the like. In addition, any addition-polymerizable unsaturated compound that is generally copolymerizable may be used.

  The total content of repeating units represented by the general formula (I) or (Ia) is generally 3 to 95 mol%, preferably 5 to 80 mol%, more preferably 7 in the total polymer composition. -70 mol%.

  The content of the repeating units represented by the general formulas (II) to (IX) is generally 1 to 80 mol%, preferably 3 to 65 mol%, more preferably 5 to 50 in the total polymer composition. Mol%.

  The total content of the repeating units represented by the general formulas (FI) to (FVI) is generally 1 to 80 mol%, preferably 3 to 65 mol%, more preferably 5 in the total polymer composition. ˜50 mol%.

  The content of the repeating unit having an acid-decomposable group is generally 5 to 95 mol%, preferably 7 to 80 mol%, more preferably 10 to 70 mol% in the total polymer composition.

  The acid-decomposable resin (A) can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, monomer species are charged into a reaction vessel in a batch or in the course of reaction, and if necessary, a reaction solvent such as ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, methyl ethyl ketone, Dissolve in a solvent that can dissolve various monomers, such as ketones such as methyl isobutyl ketone, ester solvents such as ethyl acetate, and propylene glycol monomethyl ether acetate described later, and then use nitrogen, argon, etc. Polymerization is started using a commercially available radical initiator (azo initiator, peroxide, etc.) as necessary under an active gas atmosphere. 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 20% by mass or more, preferably 30% by mass or more, and more preferably 40% by mass or more. The reaction temperature is 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 50-100 ° C. Some monomers can be synthesized more suitably when anionic polymerization is used. The polymerization method is described in “Chemical Chemistry Course 28, Polymer Synthesis” (Maruzen) edited by the Chemical Society of Japan and “New Experimental Chemistry Course 19, Polymer Chemistry” (Maruzen) edited by the Chemical Society of Japan.

  It is preferable that a small amount of metal components such as Na, K, Ca, Fe, and Mg contained in the acid-decomposable resin (A). Specifically, the metal species content contained in the resin is preferably 300 ppb or less, more preferably 200 ppb or less, and still more preferably 100 ppb or less.

  The preferred molecular weight of the acid-decomposable resin (A) is 1,000 to 200,000 on a weight average, and more preferably 3,000 to 20,000. The molecular weight dispersity (Mw / Mn) is usually 1 to 10, preferably 1 to 3, more preferably 1 to 2. The smaller the molecular weight distribution, the smoother the resolution, the resist shape, and the side wall of the resist pattern, and the better the line edge roughness.

  The amount of the acid-decomposable resin (A) added is generally 50% by mass or more, preferably 60 to 98% by mass, more preferably 65 to 95% by mass, based on the total solid content of the composition. Is done.

[2] (B) Compound that generates acid by the action of actinic rays or radiation A compound that generates an acid by the action of actinic rays or radiation (hereinafter referred to as “acid generator”) used in the positive resist composition of the present invention. Will be described below.

  Acid generators that can be used in the present invention include photoinitiators for photocationic polymerization, photoinitiators for photoradical polymerization, photodecolorants for dyes, photochromic agents, and microresists. A known compound that generates an acid by the action of active light or radiation and a mixture thereof can be appropriately selected and used.

  For example, diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, onium salts such as arsonium salts, organic halogen compounds, organic metal / organic halides, acid generators having o-nitrobenzyl type protecting groups And compounds capable of generating sulfonic acid by photolysis represented by imino sulfonate and the like, and disulfone compounds.

  Further, a group in which an acid is generated by the action of these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, for example, US Pat. No. 3,849,137, German Patent No. 3914407, JP 63-26653, JP 55-164824, JP 62-69263, JP 63-146038, JP 63-163452, JP 62-153853, JP 63- The compounds described in No. 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.

  Of the above-mentioned compounds that can be decomposed by the action of actinic rays or radiation to generate an acid, those that are particularly effective are described below.

  (1) An iodonium salt represented by the following general formula (PAG3) or a sulfonium salt represented by the general formula (PAG4)

Here, Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aryl group. Preferable substituents include an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, a nitro group, a carboxyl group, an alkoxycarbonyl group, a hydroxy group, a mercapto group, and a halogen atom.

R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ each independently represents an alkyl group or an aryl group. Preferred are aryl groups having 6 to 14 carbon atoms, alkyl groups having 1 to 8 carbon atoms, and substituted derivatives thereof. Preferred substituents are an aryl group having 1 to 8 carbon atoms, an alkyl group having 1 to 8 carbon atoms, a nitro group, a carboxyl group, a hydroxy group, and a halogen atom. An alkoxy group having 1 to 8 carbon atoms, a carboxyl group, and an alkoxycarbonyl group;

Z ⁻ represents a counter anion, such as perfluoroalkanesulfonic acid anion such as BF ₄ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , SiF ₆ ²⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , pentafluoro Examples include, but are not limited to, condensed polynuclear aromatic sulfonate anions such as benzenesulfonate anion and naphthalene-1-sulfonate anion, anthraquinone sulfonate anion, and sulfonate group-containing dyes.

Two of R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ and Ar ¹ and Ar ² may be bonded via a single bond or a substituent.

  Specific examples include the following compounds, but are not limited thereto.

  Diphenyl iodonium dodecyl benzene sulfonate, diphenyl iodonium trifluoromethane sulfonate, bis (4-trifluoromethylphenyl) iodonium trifluoromethane sulfonate, bis (4-t-butylphenyl) iodonium camphor sulfonate.

  Triphenylsulfonium dodecylbenzenesulfonate, triphenylsulfonium-2,4,6-trimethylbenzenesulfonate, triphenylsulfonium-2,4,6-triisopropylbenzenesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium perfluorooctanesulfonate , Triphenylsulfonium perfluorononane sulfonate, triphenylsulfonium camphor sulfonate, triphenylsulfonium perfluorobenzene sulfonate, triphenylsulfonium-3,4-bis (trifluoromethyl) benzene sulfonate.

  The above onium salts represented by the general formulas (PAG3) and (PAG4) are known and can be synthesized, for example, by the methods described in U.S. Pat. Nos. 2,807,648 and 4,247,473, and JP-A-53-101,331.

  (2) A disulfone derivative represented by the following general formula (PAG5) or an iminosulfonate derivative represented by the general formula (PAG6)

In the formula, Ar ³ and Ar ⁴ each independently represents an aryl group.

R ²⁰⁶ represents an alkyl group or an aryl group. A represents an alkylene group, an alkenylene group or an arylene group.

  Specific examples include the following compounds, but are not limited thereto.

  Bis (tolyl) disulfone, bis (4-methoxyphenyl) disulfone, bis (4-trifluoromethylphenyl) disulfone, phenyl-4-isopropylphenyldisulfone.

  (3) Diazodisulfone derivative represented by the following general formula (PAG7)

  Here, R represents a linear or branched alkyl group, a cycloalkyl group, or an aryl group.

  Specific examples include the following compounds, but are not limited thereto.

  Bis (phenylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (tolylsulfonyl) diazomethane, bis (t-butylsulfonyl) diazomethane.

  (4) A phenacylsulfonium derivative represented by the following general formula (PI)

In general formula (PI),
R _{1p to} R _5p represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a nitro group, a halogen atom, an alkyloxycarbonyl group or an aryl group, and at least two of R _{1p to} R _5p are bonded. To form a ring structure.

R _6p and R _7p represent a hydrogen atom, an alkyl group, a cycloalkyl group, a cyano group or an aryl group.

Y _1p and Y _2p represent an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an aromatic group containing a hetero atom, and Y _1p and Y _2p may combine to form a ring.

Y _3p represents a single bond or a divalent linking group.

X ⁻ represents a non-nucleophilic anion.

It from R _1p may be formed at least one bond to ring at least one Y _1p or Y _2p of R _5p, at least one bound at least one R _6p or R _7p of R _5p from R _1p To form a ring.

It may be bonded via a linking group at any position of R _1p to R _7p , or any position of Y _1p or Y _2p , and may have two or more structures of formula (PI).

  Specific examples of the compound represented by the formula (PI) are shown below, but the present invention is not limited thereto.

  Among the above-mentioned compounds that decompose by the action of actinic rays or radiation to generate an acid, examples of particularly preferable ones are listed below.

  The compound of the component (B) is preferably a compound that generates an organic sulfonic acid by the action of actinic rays or radiation.

  (B) The compound of a component can be used individually by 1 type or in combination of 2 or more types.

  (B) When using 2 or more types of compounds of a component, the following combinations can be mentioned.

  (B1a) a compound that generates an organic sulfonic acid having at least one fluorine atom by the action of active light or radiation, and (B1b) a compound that generates an organic sulfonic acid having no fluorine atom by the action of active light or radiation. Combination.

  (B1a) A combination of a compound that generates an organic sulfonic acid having at least one fluorine atom by the action of actinic rays or radiation and (B2) a compound that generates a carboxylic acid by the action of actinic rays or radiation.

  (B1b) A combination of a compound that generates an organic sulfonic acid having no fluorine atom by the action of actinic rays or radiation, and (B2) a compound that generates a carboxylic acid by the action of actinic rays or radiation.

  (B1a) A combination of compounds that generate an organic sulfonic acid having at least one fluorine atom by the action of actinic rays or radiation.

  The content of the component (B) compound in the positive resist composition of the present invention is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, based on the solid content of the composition. More preferably, it is 1-7 mass%.

[3] (C) Fluorine-based and / or silicon-based surfactant The positive resist composition of the present invention further comprises (C) a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant and silicon-based interface). It is preferable to contain any one or two or more of activators and surfactants containing both fluorine atoms and silicon atoms.

  When the positive resist composition of the present invention contains the above-mentioned (C) surfactant, a resist having good sensitivity and resolution and less adhesion and development defects when using an exposure light source of 250 nm or less, particularly 220 nm or less. A pattern can be given.

  As these (C) surfactants, for example, JP-A 62-36663, JP-A 61-226746, JP-A 61-226745, JP-A 62-170950, JP 63-3345, JP-A-7-230165, JP-A-8-62834, JP-A-9-54432, JP-A-9-5988, JP-A-2002-277862, US Pat. No. 5,405,720. , No. 5,360,692, No. 5,529,881, No. 5,296,330, No. 5,436,098, No. 5,576,143, No. 5,294,511, No. 5,824,451 The following commercially available surfactants can also be used as they are.

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

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

  (C) 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 resist composition (excluding the solvent).

[4] (D) Organic basic compound In the composition of the present invention, performance variation (pattern T-top shape formation, sensitivity variation, pattern line width variation) over time after irradiation with actinic rays or radiation until heat treatment Etc.) and performance fluctuations over time after application, and further, an acid diffusion inhibitor may be added for the purpose of preventing excessive diffusion (degradation of resolution) of the acid during heat treatment after irradiation with actinic rays or radiation. preferable. The acid diffusion inhibitor is an organic basic compound, for example, an organic basic compound containing basic nitrogen, and a compound having a pKa value of the conjugate acid of 4 or more is preferably used.

  Specifically, the structures of the following formulas (A) to (E) can be exemplified.

Here, R ²⁵⁰ , R ²⁵¹ and R ²⁵² may be the same or different, and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or 6 to 20 carbon atoms. Wherein R ²⁵¹ and R ²⁵² may combine with each other to form a ring. The alkyl group, cycloalkyl group, and aryl group may have a substituent. Examples of the alkyl group having a substituent include an aminoalkyl group having 1 to 20 carbon atoms and a hydroxyalkyl group having 1 to 20 carbon atoms. Examples of the cycloalkyl group having a substituent include an aminocycloalkyl group having 3 to 20 carbon atoms and a hydroxycycloalkyl group having 3 to 20 carbon atoms.

R ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R ²⁵⁶ may be the same or different and each represents an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 20 carbon atoms.

  Further preferred compounds are nitrogen-containing basic compounds having two or more nitrogen atoms of different chemical environments in one molecule, and particularly preferably both a substituted or unsubstituted amino group and a ring structure containing a nitrogen atom. Or a compound having an alkylamino group.

  Preferred examples include substituted or unsubstituted guanidine, substituted or unsubstituted aminopyridine, substituted or unsubstituted aminoalkylpyridine, substituted or unsubstituted aminopyrrolidine, substituted or unsubstituted indazole, imidazole, substituted or unsubstituted Substituted pyrazole, substituted or unsubstituted pyrazine, substituted or unsubstituted pyrimidine, substituted or unsubstituted purine, substituted or unsubstituted imidazoline, substituted or unsubstituted pyrazoline, substituted or unsubstituted piperazine, substituted or unsubstituted Aminomorpholine, substituted or unsubstituted aminoalkylmorpholine, and the like. Preferred substituents are amino group, aminoalkyl group, alkylamino group, aminoaryl group, arylamino group, alkyl group, alkoxy group, acyl group, acyloxy group, aryl group, aryloxy group, nitro group, hydroxyl group, cyano group It is.

Particularly preferred compounds include guanidine, 1,1-dimethylguanidine, 1,1,3,3-tetramethylguanidine, imidazole, 2-methylimidazole, 4-methylimidazole, N-methylimidazole, 2-phenylimidazole, 4 , 5-diphenylimidazole, 2,4,5-triphenylimidazole, 2-aminopyridine, 3-aminopyridine, 4-aminopyridine, 2-dimethylaminopyridine, 4-dimethylaminopyridine, 2-diethylaminopyridine, 2- (Aminomethyl) pyridine, 2-amino-3-methylpyridine, 2-amino-4-methylpyridine, 2-amino-5-methylpyridine, 2-amino-6-methylpyridine, 3-aminoethylpyridine, 4- Aminoethylpyridine,
3-aminopyrrolidine, piperazine, N- (2-aminoethyl) piperazine, N- (2-aminoethyl) piperidine, 4-amino-2,2,6,6-tetramethylpiperidine, 4-piperidinopiperidine, 2-iminopiperidine, 1- (2-aminoethyl) pyrrolidine, pyrazole, 3-amino-5-methylpyrazole, 5-amino-3-methyl-1-p-tolylpyrazole, pyrazine, 2- (aminomethyl)- Examples include 5-methylpyrazine, pyrimidine, 2,4-diaminopyrimidine, 4,6-dihydroxypyrimidine, 2-pyrazoline, 3-pyrazoline, N-aminomorpholine, N- (2-aminoethyl) morpholine. However, the present invention is not limited to this.

  These nitrogen-containing basic compounds are used alone or in combination of two or more.

  The use ratio of the acid generator and the organic basic compound in the composition is preferably (acid generator) / (organic basic compound) (molar ratio) = 2.5 to 300. By setting the molar ratio to 2.5 or more, high sensitivity is obtained, and by setting the molar ratio to 300 or less, it is possible to reduce the thickness of the resist pattern over time until post-exposure heat treatment and improve resolution. . (Acid generator) / (organic basic compound) (molar ratio) is preferably 5.0 to 200, more preferably 7.0 to 150.

[5] Solvent The composition of the present invention is dissolved in a solvent that dissolves each of the above components and coated on a support. Examples of the solvent used here include 1-methoxy-2-propanol acetate (propylene glycol monomethyl ether acetate), 1-methoxy-2-propanol (propylene glycol monomethyl ether), ethylene dichloride, cyclohexanone, cyclopentanone, and 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 monoethyl ether, propylene glycol monomethyl ether acetate, toluene, Ethyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate Ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofuran and the like are preferable, 1-methoxy-2-propanol acetate, 1-methoxy- 2-propanol is particularly preferred. These solvents are used alone or in combination. When mixed and used, those containing 1-methoxy-2-propanol acetate or those containing 1-methoxy-2-propanol are preferred.

[6] Non-polymeric dissolution inhibitor (X)
The positive resist composition of the present invention preferably further contains a non-polymer type dissolution inhibitor. Here, the non-polymer type dissolution inhibitor is a compound in which at least two or more acid-decomposable groups are present in a compound having a molecular weight of 3000 or less, and the solubility in an alkali developer is increased by the action of an acid. is there. In particular, it is preferable from the viewpoint of transparency that a fluorine atom is substituted in the mother nucleus.

  3-50 mass% is preferable with respect to the polymer in a composition, More preferably, 5-40 mass%, More preferably, it is 7-30 mass% with respect to the polymer in a composition. By adding the component (X), sensitivity and contrast are further improved.

  Specific examples of the component (X) are shown below, but the present invention is not limited to these specific examples.

  In the manufacture of precision integrated circuit elements, the pattern forming process on the resist film is carried out by applying the positive resist composition of the present invention on a substrate (eg, a transparent substrate such as a silicon / silicon dioxide covering, a glass substrate, an ITO substrate). A good resist pattern can be formed by applying an object to form a resist film, then irradiating the resist film with an actinic ray or radiation drawing apparatus, heating, developing, rinsing and drying.

  Examples of the alkaline developer of the positive resist composition of the present invention include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, ethylamine, and n-propylamine. Primary amines, secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcoholamines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, An aqueous solution of alkalis such as quaternary ammonium salts such as tetraethylammonium hydroxide and choline, cyclic amines such as pyrrole and piperidine, and the like can be used. Furthermore, an appropriate amount of an alcohol such as isopropyl alcohol or a nonionic surfactant may be added to the alkaline aqueous solution.

  Among these alkaline developers, quaternary ammonium salts are preferable, and tetramethylammonium hydroxide and an aqueous solution of choline are more preferable.

  The alkali concentration in the alkali developer is usually 0.1 to 20% by mass, preferably 0.2 to 15% by mass, and more preferably 0.5 to 10% by mass.

  The pH of the alkaline developer is usually 10.0 to 15.0, preferably 10.5 to 14.5, and more preferably 11.0 to 15.0.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, the content of this invention is not limited by this.

Synthesis Example 1 (Synthesis of Intermediate (M-1))
100 g (1 mol) of 2,2,2-trifluoroethanol and 158 g (2 mol) of pyridine were dissolved in 1 L of tetrahydrofuran, and a tetrahydrofuran (400 ml) solution of 286 g (1.5 mol) of p-toluenesulfonic acid chloride was dropped. After dropping, the mixture was stirred for 5 hours, neutralized with 1N aqueous HCl, and extracted with ethyl acetate-water. The organic layer was dehydrated using anhydrous sodium sulfate, and the solvent was distilled off to obtain 223.7 g of the following intermediate (M-1) (yield 88%).

Synthesis Example 2 (Synthesis of Intermediate (M-2))
154.65 g (0.564 mol) of 5- [2,2-bis (trifluoromethyl) -2-hydroxyethyl] bicyclo [2.2.1] hept-2-ene was dissolved in 150 ml of tetrahydrofuran with stirring and cooled. Then, 750 ml of borane-tetrahydrofuran complex (1.0 M solution) was added dropwise over 1 hour. After the addition, the mixture was further stirred for 2 hours, 282 g of a sodium hydroxide aqueous solution (40 wt%) was added, and 241.2 g of hydrogen peroxide (30 wt% aqueous solution) was added dropwise over 1 hour. It stirred for 8 hours after dripping. Thereafter, the mixture was neutralized with an aqueous HCl solution, and 600 g of ethyl acetate was added to carry out a liquid separation operation. The organic layer was dehydrated using 50 g of magnesium sulfate and the solvent was distilled off, and then the product was purified by silica gel chromatography to obtain 70.87 g of the following intermediate (M-2) (43% yield).

Synthesis Example 3 (Synthesis of Intermediate (M-3))
16 g (0.4 mol) of sodium hydride (60 wt%) was added to a reaction vessel in which 80 g of dehydrated tetrahydrofuran was replaced with nitrogen, and the mixture was cooled to −78 ° C. with stirring. Thereafter, a solution of intermediate (M-2) 58.44 g (0.2 mol) in 100 g of dehydrated tetrahydrofuran was added dropwise over 30 minutes. After the addition, the mixture was further stirred for 2 hours, and then a solution of Intermediate (M-1) 50.85 g (0.2 mol) in dehydrated tetrahydrofuran (100 ml) was added dropwise over 1 hour. After the dropping, the mixture was further stirred for 4 hours while raising the temperature to room temperature. Then, it neutralized with saturated ammonium chloride aqueous solution, ethyl acetate was added, and liquid separation operation was performed. The organic layer was dehydrated using magnesium sulfate and the solvent was distilled off, and then the product was purified by silica gel chromatography to obtain 55.39 g of the following intermediate (M-3) (yield 74%).

Synthesis Example 4 (Synthesis of monomer (I))
Intermediate (M-3) 37.42 g (0.1 mol) and dehydrated tetrahydrofuran 100 ml were added to a reaction vessel purged with nitrogen, and the mixture was cooled to −78 ° C. with stirring. Thereafter, 200 ml of n-BuLi (1.0 M hexane solution) was added dropwise over 2 hours. After dropping, the mixture was further stirred for 8 hours while raising the temperature to the nitrogen temperature. Then, it neutralized with saturated ammonium chloride aqueous solution, ethyl acetate was added, and liquid separation operation was performed. The organic layer was dehydrated using magnesium sulfate, the solvent was distilled off, and the product was purified by silica gel chromatography to obtain 27.63 g of the following monomer (I) (yield 78%).

Synthesis Example 5 (Synthesis of Resin (A-1))
Monomer (I) 17.71 g (0.05 mol), 5- {2,2-bis (trifluoromethyl) -2-hydroxyethyl} bicyclo [2.2.1] hept-2-ene 15.63 g (0 0.057 mol) and 4.61 g (0.036 mol) of tBu acrylate were charged into a reaction vessel, and the reaction system was purged with nitrogen, and then 0.355 g (1.43 mmol) of a polymerization initiator V-65 (manufactured by Wako Pure Chemical Industries, Ltd.). ) And heated and stirred at 65 ° C. while flowing nitrogen through the reaction system. After 2 hours, 4 hours, 6 hours, and 8 hours, 0.355 g of V-65 was added, respectively, and the mixture was heated and stirred for a total of 20 hours. Thereafter, the mixture was cooled to room temperature, and the reaction solution was dropped into 1.5 L of hexane. The powder was taken out by filtration and dried under reduced pressure at 50 ° C. to obtain 16.32 g of resin (A-1) (yield 43%). The obtained resin (A-1) had a weight average molecular weight of 8,900 and a dispersity of 1.53 as measured by gel permeation chromatography (GPC). In addition, monomer (r) / 5- [2,2-bis (trifluoromethyl) -2-hydroxyethyl] bicyclo [2.2.1] analyzed by ¹ H-NMR, ¹³ C-NMR, and ¹⁹ F-NMR analysis. The composition ratio of hept-2-ene / tBu acrylate was 35/30/35.

  Resins (A-2) to (A-9) and Comparative Resin 1 were obtained in the same manner except that the monomer to be added was changed.

  Hereinafter, the structures of Resins (A-1) to (A-9) and Comparative Resin 1 are shown.

  Table 1 below shows the repeating unit composition ratio, weight average molecular weight, and dispersity of the resins (A-1) to (A-9) and the comparative resin 1.

Examples 1 to 9 and Comparative Example 1
<Resist solution preparation>
Resin: 1.2 g, acid generator: 0.030 g, surfactant: 100 ppm with respect to resin solution, organic basic compound: 0.0012 g, non-polymer type dissolution inhibitor: 0.24 g shown in Table 2 A polymer solution dissolved in 19.6 g was filtered through a 0.1 μm polytetrafluoroethylene filter to prepare a positive resist solution.

<ArF exposure evaluation>
The positive resist solution prepared as described above is uniformly applied on a silicon wafer coated with an antireflection film (DUV42-6 manufactured by Brewer Science. Inc.) using a spin coater, and dried by heating at 120 ° C. for 60 seconds. A positive resist film having a thickness of 0.1 μm was formed. The resist film was subjected to pattern exposure using an ArF microstepper using a line and space mask (line / space = 1: 1), and immediately after the exposure, it was heated on a hot plate at 130 ° C. for 90 seconds. Further, the film was developed with a 2.38 wt% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 60 seconds, rinsed with pure water for 30 seconds, and then dried. The resist performance of the pattern on the silicon wafer thus obtained was evaluated by the following method. The results are shown in Table 2.

[Limit resolution]
The minimum line width that can be resolved at line / space = 1: 1 was confirmed by cross-sectional SEM observation, and the line width at that time was evaluated as the critical resolution. A smaller value indicates better performance.

〔sensitivity〕
The minimum exposure amount for reproducing a mask pattern having a line width of 150 nm (line / space = 1: 1) was evaluated as sensitivity.

[Development defect evaluation]
With respect to the resist pattern obtained as described above, the number of development defects was measured by a KLA-2112 machine manufactured by KLA-Tencor Corporation, and the obtained primary data value was taken as a measurement result.

<F2 exposure evaluation>
The positive resist solution prepared as described above is applied onto a silicon wafer that has been subjected to hexamethyldisilazane treatment using a spin coater, and is heated and dried at 120 ° C. for 90 seconds to form a positive resist having a thickness of 0.1 μm. A film was formed. The resist film was evaluated using a 157 nm laser exposure / dissolution behavior analyzer VUVES-4500 (manufactured by RISOTEC JAPAN), and the sensitivity by 157 nm exposure and the dissolution contrast of the exposed / unexposed areas. The evaluation results are shown in Table 2.

〔sensitivity〕
Sensitivity here refers to a wafer that has been exposed to heat and dried at 130 ° C. for 90 seconds, developed using a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 60 seconds, and then pure water for 30 seconds. When the film thickness is measured after rinsing and drying, it indicates the minimum exposure amount at which the film thickness becomes zero.

〔contrast〕
The contrast here refers to the slope (tan θ) of the exposure dose-dissolution rate curve.

N-1: Hexamethylenetetramine N-2: 1,5-diazabicyclo [4.3.0] -5-nonene N-3: 1,8-diazabicyclo [5.4.0] -7-undecene D-1 : Megafuck F176 (Dainippon Ink Chemical Co., Ltd.) (Fluorine)
D-2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.) (fluorine and silicon)
S-1: Methyl lactate S-2: Propylene glycol monomethyl ether acetate S-3: Propylene glycol monomethyl ether

  From Table 2, it can be seen that the resist composition of the present invention has excellent performance in resolution, sensitivity, development defect and dissolution contrast.

Claims (6)

(A) a resin having at least one repeating unit represented by the following general formula (I), which decomposes by the action of an acid and increases the solubility in an alkali developer, and (B) an acid by the action of actinic rays or radiation. A positive resist composition comprising a generated compound.

In general formula (I),
R ₁ and R ₂ each independently represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group. However, at least one of R ₁ and R ₂ represents a fluorine atom or an alkyl group having at least one fluorine atom.
R ₃ represents a hydrogen atom, a cyano group or an alkyl group.
X represents an alkali-soluble group, a group having an alkali-soluble group protected with an acid-decomposable group, or a group having an alkali-soluble group protected with a non-acid-decomposable group.
L ₁ represents a single bond or a divalent linking group.
L ₂ represents a (n + 1) -valent linking group.
n represents an integer of 1 to 4. The positive resist composition according to claim 1, wherein X in the general formula (I) is represented by the following general formula (A).

In general formula (A),
R _{31 to} R ₃₆ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{31 to} R ₃₆ represents a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom.
Y represents a hydrogen atom or an organic group.
L ₃ represents a single bond or a divalent linking group. The positive resist composition according to claim 1, wherein L ₂ in the general formula (I) has an alicyclic structure. The positive resist composition according to claim _1, wherein R ₁ and R ₂ in the general formula (I) are both fluorine atoms. The positive resist composition according to claim 1, wherein L ₁ in the general formula (I) is a single bond or an alkylene group having 1 to 4 carbon atoms. A pattern forming method comprising: forming a resist film from the positive resist composition according to claim 1; and exposing and developing the resist film.