JP2005189712A - Positive resist composition and pattern forming method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive resist composition suitable for use of an exposure light source of ≤250 nm, particularly F<SB>2</SB>excimer laser light (157 nm), and to specifically provide a positive resist composition exhibiting satisfactory transmittance at the time of using a light source of 157 nm and having small PEB temperature dependency, a small rate of variability of sensitivity and improved resolution and a pattern forming method using the same. <P>SOLUTION: The positive resist composition contains a fluorine-atom-containing resin having at least two groups which are decomposed by the action of an acid to increase solubility in an alkaline developer and a compound which generates an acid upon irradiation with an actinic ray or a radiation. The pattern forming method uses the same. <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. More specifically, the present invention relates to a positive resist composition capable of forming a highly refined pattern using vacuum ultraviolet light of 250 nm or less.

  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 manufacture of a semiconductor device having a degree of integration of 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 sufficient results have been achieved in processing lines up to about 0.3 μm. Further, in the manufacture of a semiconductor device having an integration degree of 256 Mbit or more, KrF excimer laser light (248 nm) has been adopted as an exposure light source instead of i-line.
Furthermore, 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 further F ₂ excimer laser light to form a pattern of 0.1 μm or less. The use of (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 composed mainly 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. A so-called chemically amplified resist has been developed which is a combination of a compound generating photoacid (a photoacid generator).

  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. On the other hand, it is reported in Non-Patent Document 1 that a resin into which a fluorine atom (perfluoro structure) is introduced has sufficient transparency at 157 nm, and an effective fluororesin structure is described in Non-Patent Document 2 and Non-Patent Document. 3, Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, and the like have been studied on resist compositions containing fluorine-containing resins.

  However, there are still many insufficient points, and various improvements are desired. For example, when a wafer having a large diameter is used, it has been found that temperature variations in heating (PEB) using a hot plate after exposure affect the resulting pattern. Improvement is desired. Moreover, it is desired that the sensitivity fluctuation due to the fluctuation of the PEB temperature is small.

International Publication No. 00/67072 Pamphlet US Patent Application Publication No. 2001/0010890 European Patent Application No. 0829766 JP 2002-244300 A Proc. SPIE., 1999, 3678, p. 13 Journal of Photopolymer Science Technology (J. Photoplym. Sci. Technol.), 2001, Vol. 14, p. 603 Journal of Photopolymer Science Technology (J. Photoplym. Sci. Technol.), 2002, Vol. 15, p. 583

An object of the present invention is to provide a positive resist composition suitable for use as an exposure light source of 250 nm or less, particularly F ₂ excimer laser light (157 nm), and more specifically, sufficient when a light source of 157 nm is used. The present invention provides a positive resist composition that exhibits excellent transparency, has a small PEB temperature dependency, a small sensitivity fluctuation rate, and an improved resolution, 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 the following specific composition, and have reached the present invention.
That is, the present invention has the following configuration.

(1) A group that decomposes by the action of an acid represented by the following general formula (Z1) to increase the solubility in an alkaline developer and an alkali development that decomposes by the action of an acid represented by the general formula (Z2) A resin having at least two different groups selected from groups that increase solubility in liquid and containing fluorine atoms, and
(B) A positive resist composition comprising a compound that generates an acid upon irradiation with actinic rays or radiation.

In general formula (Z1) or (Z2), R _{1z to} R _3z and R _5z each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, or an aryl group. R _4z represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. However, any two of R _1z , R _2z and R _3z , and R _4z and R _5z may be bonded to form a ring.

  (2) The positive resist composition as described in (1) above, wherein the resin as the component (A) further has an alicyclic hydrocarbon structure.

  (3) The above-mentioned (1) or (A), wherein the resin of component (A) further comprises at least one repeating unit formed by a compound substituted with a group represented by the following general formula (Y) The positive resist composition as described in (2).

In general formula (Y), L ₁ represents a single bond or a methylene group. R _{1 to} R ₆ each independently represents a fluorine atom or a hydrogen atom. However, at least one of R _{1 to} R ₆ is a fluorine atom. One of R _{1 to} R ₆ may be connected to the main chain of the polymer via a carbon chain to form a ring. R ₄ may be bonded to the α carbon atom of the hydroxyl group to form a ring.

  (4) The positive type resin as described in any one of (1) to (3) above, wherein the resin of component (A) further has an alicyclic hydrocarbon structure in the main chain. Resist composition.

  (5) The resin (A) further has at least one repeating unit selected from the group of repeating units represented by the following general formulas (I) to (VI) (1) ) Positive resist composition.

In general formulas (I) to (VI),
X ¹ and X ² represent a hydrogen atom or a group that decomposes by the action of an acid. Ra, Rb and Rc each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group. AR represents an alicyclic hydrocarbon structure. Q represents a hydrogen atom or a polar group. R _{11 to} R ₁₆ each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group. However, at least one of R _{11 to} R ₁₆ represents a fluorine atom or a fluoroalkyl group. R _{21 to} R ₂₆ each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group. However, at least one of R _{21 to} R ₂₆ represents a fluorine atom or a fluoroalkyl group. R _1a represents a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a cyano group or a trifluoromethyl group. Rf represents a fluorine atom or a trifluoromethyl group. Raf, Rbf, Rcf and Rdf each independently represent a hydrogen atom, a fluorine atom or a fluoroalkyl group, but at least one represents a fluorine atom or a fluoroalkyl group. m1 represents 0 or 1. m2 represents an integer of 1 to 5. m3 represents an integer of 1 to 5. n represents 0 or 1. p represents 0 or 1.

  (6) The resin of component (A) has at least one group represented by general formula (Z1) and one group represented by general formula (Z2), as described in (1) above Positive resist composition.

  (7) The positive resist composition as described in (1) above, wherein the group represented by the general formula (Z1) or (Z2) is substituted with the main chain of the resin.

  (8) The positive resist composition as described in (1) above, wherein the group represented by the general formula (Z1) or (Z2) is substituted with an alicyclic hydrocarbon structure.

  (9) A pattern forming method comprising: forming a resist film from the resist composition according to any one of (1) to (8) above; and exposing and developing the resist film.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a positive resist composition having sufficient transparency at 157 nm, small PEB temperature dependency and sensitivity fluctuation rate, and improved resolution, and a pattern forming method using the same.

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 has a substituent with what does not have 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). _{Further, -C (R 1 R 2 R} 3) or -CR ₁ R ₂ R ₃ means a group of a group represented by each of R ₁ to R ₃ to the carbon atom bonded by a single bond.

[1] (A) A resin having two different groups represented by general formula (Z1) or (Z2) and having increased solubility in an alkali developer due to the action of an acid containing a fluorine atom.
The resin (A) contained in the positive resist composition of the present invention is a group (acid-decomposable group) that is decomposed by the action of an acid represented by the general formula (Z1) to increase the solubility in an alkali developer. And having at least two different groups selected from groups (acid-decomposable groups) that are decomposed by the action of an acid represented by the general formula (Z2) to increase the solubility in an alkali developer, and contain a fluorine atom Resin (acid-decomposable resin).
Here, the at least two different acid-decomposable groups contained in the resin (A) are two groups represented by the general formula (Z1), two groups represented by the general formula (Z2), Or 1 type of group represented by general formula (Z1) and 1 type of group represented by general formula (Z2) may be sufficient.
The resin (A) preferably has at least one group represented by the general formula (Z1) and one group represented by the general formula (Z2).

In general formula (Z1) or (Z2), R _{1z to} R _3z and R _5z each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, or an aryl group. R _4z represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. However, any two of R _1z , R _2z and R _3z , and R _4z and R _5z may be bonded to form a ring.

The alkyl group as R _{1z to} R _5z is preferably a linear or branched alkyl group having 1 to 12 carbon atoms, more preferably a linear or branched alkyl group having 1 to 10 carbon atoms, More preferably, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group Can be mentioned. The alkyl group of R _{1z to} R _5z may be a fluoroalkyl group or a _{hydroxyfluoroalkyl} group by substitution with a fluorine atom or a hydroxyl group. The fluoroalkyl group refers to an alkyl group in which at least one hydrogen atom is fluorinated, preferably having 1 to 6 carbon atoms, and more preferably having 1 to 3 carbon atoms. Specific examples of the fluoroalkyl group include, for example, a trifluoromethyl group, a difluoromethyl group, a fluoromethyl group, a pentafluoroethyl group, a 2,2,2-trifluoroethyl group, a 2-fluoroethyl group, 3, 3, A 3-trifluoropropyl group can be exemplified. A trifluoromethyl group is particularly preferable. The hydroxyfluoroalkyl group is a fluoroalkyl group substituted with at least one hydroxyl group, preferably having 1 to 10 carbon atoms, more preferably having 1 to 5 carbon atoms. Specific examples of the hydroxyfluoroalkyl group include, for example, —CF ₂ OH, —CH ₂ CF ₂ OH, —CH ₂ CF ₂ CF ₂ OH, —C (CF ₃ ) ₂ OH, —CF ₂ CF (CF ₃ ). OH, —CH ₂ C (CF ₃ ) ₂ OH, and the like.

The cycloalkyl group having an alicyclic hydrocarbon structure of R _{1z to} R _5z may be monocyclic or polycyclic, and may have a substituent. Specific examples include groups having a monocyclo, bicyclo, tricyclo, tetracyclo structure or the like having 5 or more carbon atoms. The carbon number is preferably 6-30, and particularly preferably 7-25.

Preferred examples of the cycloalkyl group include adamantyl group, noradamantyl group, decalin residue, tricyclodecanyl group, tetracyclododecanyl group, norbornyl group, cedrol group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecanyl group. And cyclododecanyl group. More preferable examples include an adamantyl group, a decalin residue, a norbornyl group, a cedrol group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecanyl group, and a cyclododecanyl group. The cycloalkyl group of R _{1z to} R _3z or R _5z may be substituted with a fluorine atom or a hydroxyl group to form a fluorocycloalkyl group or a hydroxycycloalkyl group.

The alkenyl group _{represented by} R _{1z to} R _5z 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 aralkyl group of R _{1z to} R _5z 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 aryl group of R _{1z to} R _5z is preferably an aryl group having 6 to 10 carbon atoms, and examples thereof include a phenyl group, a tolyl group, a dimethylphenyl group, and a 9,10-dimethoxyanthryl group.

Any two of R _1z , R _2z and R _3z , and R _4z and R _5z may be bonded to form a ring. The ring to be formed is preferably a cycloalkyl ring, and the cycloalkyl ring may be monocyclic or polycyclic. Specific examples include cycloalkyl rings having 5 or more carbon atoms such as monocyclo, bicyclo, tricyclo, and tetracyclo. The carbon number is preferably 6-30, and particularly preferably 7-25. Preferred examples of the cycloalkyl ring include an adamantane ring, noradamantane ring, decalin ring, tricyclodecane ring, tetracyclododecane ring, norbornane ring, cyclohexane ring, cycloheptane ring, cyclooctane ring, cyclodecane ring, cyclododecane ring and the like. Can be mentioned. More preferable examples include an adamantane ring, a norbornane ring, and a cyclohexane ring.
The cycloalkyl ring may further have an alkyl group, an alkoxy group or the like as a substituent. Further, some of the carbon atoms constituting the cycloalkyl ring may be substituted with a heteroatom such as an oxygen atom or a sulfur atom.

  Examples of the substituent that the substituent may have include, in addition to the substituent represented by the following general formula (Y), for example, a hydroxyl group, a carboxy group, a cyano group, a halogen atom (for example, chlorine atom, bromine). Atoms, fluorine atoms, iodine atoms), alkoxy groups (preferably having 1 to 4 carbon atoms, such as methoxy group, ethoxy group, propoxy group, butoxy group, etc.), acyl groups (preferably having 2 to 5 carbon atoms, such as formyl group) , An acetyl group, etc.), an acyloxy group (preferably having a carbon number of 2 to 5, such as an acetoxy group), an aryl group (preferably having a carbon number of 6 to 14, such as a phenyl group), and the like.

In general formula (Y), L ₁ represents a single bond or a methylene group. R _{1 to} R ₆ each independently represents a fluorine atom or a hydrogen atom. However, at least one of R _{1 to} R ₆ is a fluorine atom. One of R _{1 to} R ₆ may be connected to the main chain of the polymer via a carbon chain to form a ring. R ₄ may be bonded to the α carbon atom of the hydroxyl group to form a ring.
The details of the group represented by the general formula (Y) are the same as those described later.

  Hereinafter, although the preferable specific example of group represented by general formula (Z1) is given, this invention is not limited to this.

  Hereinafter, although the preferable specific example of group represented by general formula (Z2) is given, this invention is not limited to this.

The repeating unit containing the group represented by the general formula (Z1) or the group represented by the general formula (Z2) may be any repeating unit, but a repeating unit composed of (meth) acrylic acid ester, A repeating unit having a fluorine atom in the chain and a repeating unit having an alicyclic structure such as norbornene in the main chain are preferred.
The group represented by the general formula (Z1) or (Z2) is preferably substituted on the main chain of the resin, and the group represented by the general formula (Z1) or (Z2) is an alicyclic hydrocarbon. It is also preferable to substitute the structure.

  Hereinafter, although the specific example of the repeating unit which has group represented by general formula (Z1) is given, this invention is not limited to this.

  Hereinafter, although the specific example of the repeating unit which has group represented by general formula (Z2) is given, this invention is not limited to this.

The resin (A) preferably has an alicyclic hydrocarbon as shown in the preferred specific examples of the repeating unit having the groups represented by the general formulas (Z1) and (Z2).
The alicyclic hydrocarbon may be monocyclic or polycyclic. Specific examples include alicyclic hydrocarbon structures such as monocyclo, bicyclo, tricyclo, and tetracyclo having 5 or more carbon atoms. The carbon number is preferably 6-30, and particularly preferably 7-25.

  Preferred examples of the alicyclic hydrocarbon include adamantane, noradamantane, decalin, tricyclodecane, tetracyclododecane, norbornane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, and cyclododecane. More preferable examples include adamantane, norbornane, and cyclohexane.

  The resin (A) may further have at least one repeating unit formed by a compound substituted with a group represented by the following general formula (Y).

In general formula (Y), L ₁ represents a single bond or a methylene group. R _{1 to} R ₆ each independently represents a fluorine atom or a hydrogen atom. However, at least one of R _{1 to} R ₆ is a fluorine atom. One of R _{1 to} R ₆ may be connected to the main chain of the polymer via a carbon chain to form a ring. R ₄ may be bonded to the α carbon atom of the hydroxyl group to form a ring.

One of R _{1 to} R ₆ may be connected to the polymer main chain via a carbon chain to form a ring. As this carbon chain, C1-C5 alkylene groups, such as a methylene group and ethylene group, can be mentioned, for example.

  It is preferable that the resin A further has at least one repeating unit formed by a vinyl ether compound.

  It is preferable that the resin (A) further has at least one repeating unit selected from the group of repeating units represented by the general formulas (I) to (VI).

In general formulas (I) to (VI),
X ¹ and X ² represent a hydrogen atom or a group that decomposes by the action of an acid.
Ra, Rb and Rc each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group.
AR represents an alicyclic hydrocarbon structure.
Q represents a hydrogen atom or a polar group.
R _{11 to} R ₁₆ each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group. However, at least one of R _{11 to} R ₁₆ represents a fluorine atom or a fluoroalkyl group.
R _{21 to} R ₂₆ each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group. However, at least one of R _{21 to} R ₂₆ represents a fluorine atom or a fluoroalkyl group.
R _1a represents a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a cyano group or a trifluoromethyl group.
Rf represents a fluorine atom or a trifluoromethyl group.
Raf, Rbf, Rcf and Rdf each independently represent a hydrogen atom, a fluorine atom or a fluoroalkyl group, but at least one represents a fluorine atom or a fluoroalkyl group.
m1 represents 0 or 1.
m2 represents an integer of 1 to 5.
m3 represents an integer of 1 to 5.
n represents 0 or 1.
p represents 0 or 1.

Examples of the group (hereinafter also referred to as “acid-decomposable group”) that is decomposed by the action of an acid of X ¹ and X ² and is solubilized in an alkali developer include —C (R ₀₁ ) (R ₀₂ ) (OR _{50), - C (R 51} ) (R 52) (R 53), - COO-C (R 51) (R 52) (R 53), - CH 2 COO-C (R 51) (R 52) ( R ₅₃ ) and the like. R _{50 to} R ₅₃ each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group.
R ₀₁ and R ₀₂ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. R ₀₁ and R ₅₀ and R ₅₂ and R ₅₃ may be bonded to each other to form a ring.

As the alkyl group for R _{50 to} R ₅₃ , R ₀₁ and R ₀₂ , 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, a sec-butyl group, A 2-hexyl group, an octyl group, etc. can be mentioned.

The cycloalkyl group for R _{50 to} R ₅₃ , R ₀₁ and R ₀₂ 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, tetracyclododecyl group. Group, androstanyl group and the like.

The aryl group of R _{50 to} R ₅₃ , R ₀₁ and R ₀₂ is preferably an aryl group having 6 to 10 carbon atoms, such as a phenyl group, a tolyl group, a dimethylphenyl group, a 9,10-dimethoxyanthryl group, and the like. Can be mentioned.

The aralkyl group represented by R _{50 to} R ₅₃ , R ₀₁ and R ₀₂ 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 _{50 to} R ₅₃ , R ₀₁ and R ₀₂ 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.

Examples of the substituent that R _{50 to} R ₅₃ , R ₀₁ and R ₀₂ may have include an alkyl group and a fluoroalkyl group.
As the alkyl group as the substituent, the alkyl groups exemplified for R _{50 to} R ₅₃ , R ₀₁ and R ₀₂ are preferable.
The fluoroalkyl group as the substituent is preferably a fluoroalkyl group having 1 to 3 carbon atoms. For example, a trifluoromethyl group, a difluoromethyl group, a fluoromethyl group, a pentafluoroethyl group, 2,2,2- A trifluoroethyl group, a 2-fluoroethyl group, a 3,3,3-trifluoropropyl group, etc. can be mentioned.

  Ra, Rb and Rc each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group, and in particular, Rc is preferably a fluorine atom or a trifluoromethyl group.

R _{11 to} R ₁₆ each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group. However, at least one of R _{11 to} R ₁₆ represents a fluorine atom or a fluoroalkyl group.
R _{21 to} R ₂₆ each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group. However, at least one of R _{21 to} R ₂₆ represents a fluorine atom or a fluoroalkyl group.
In particular, each of R _{11 to} R ₁₆ and R _{21 to} R ₂₆ is preferably a fluorine atom.

  AR represents an alicyclic hydrocarbon structure, and the alicyclic hydrocarbon structure may be monocyclic or polycyclic. Specific examples include alicyclic hydrocarbon structures such as monocyclo, bicyclo, tricyclo, and tetracyclo having 5 or more carbon atoms. The carbon number is preferably 6-30, and particularly preferably 7-25.

Preferable examples of the alicyclic hydrocarbon structure of AR include adamantane, noradamantane, decalin, tricyclodecane, tetracyclododecane, norbornane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, cyclododecane and the like. More preferable examples include adamantane, norbornane, and cyclohexane.
The alicyclic hydrocarbon structure of AR may further have an alkyl group, an alkoxy group or the like as a substituent.

  Q represents a hydrogen atom or a polar group. The polar group is, for example, a group having a halogen atom or a hetero atom, preferably a chlorine atom, a hydroxyl group or a cyano group, and more preferably a hydroxyl group.

  Hereinafter, specific examples of the repeating units represented by the general formulas (I) to (VI) will be given.

  Hereinafter, although the specific example of the repeating unit represented by general formula (I) is given, it is not limited to these.

  Hereinafter, although the specific example of the repeating unit represented by general formula (II) is given, it is not limited to these.

  Hereinafter, although the specific example of the repeating unit represented by general formula (III) is given, it is not limited to these.

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

  Hereinafter, although the specific example of the repeating unit represented by general formula (V) is given, it is not limited to these.

  Hereinafter, although the specific example of the repeating unit represented by general formula (VI) is given, it is not limited to these.

Resin (A) may polymerize other polymerizable monomers in addition to the above repeating units.
Examples of copolymerizable monomers that can be used in combination include acrylic esters, acrylamides, methacrylic esters, methacrylamides, allyl compounds, vinyl esters, styrenes, crotonic esters, dialkyl itaconates, Mention may be made of maleic acid or dialkyl esters of fumaric acid, maleic anhydride, maleimide, acrylonitrile, methacrylonitrile, maleilonitrile and the like. In addition, any addition-polymerizable unsaturated compound that is generally copolymerizable may be used.

  Hereinafter, although the specific example of resin (A) is given, this invention is not limited to this.

  The resin (A) preferably has 1 to 30 fluorine atoms, more preferably 3 to 20 repeating units, preferably 20 to 100 mol%, more preferably, based on all repeating units constituting the resin. Contains 50 to 100 mol%.

  In the resin (A), the total amount of the repeating units having a group represented by the general formula (Z1) or (Z2) is preferably 10 to 60 mol%, more preferably 20%, based on all repeating units. -40 mol%.

  The total amount of repeating units having an alicyclic hydrocarbon structure is preferably 10 to 100 mol%, more preferably 50 to 100 mol%, based on all repeating units.

  The content of the repeating unit containing a group represented by the general formula (Y) is preferably 30 to 70 mol%.

  The content of the repeating unit represented by any one of the general formulas (I) to (VI) is preferably 40 to 90 mol%, preferably 60 to 80 mol%, based on all repeating units, as a total amount. It is more preferable.

  Resin (A), which is an acid-decomposable resin, decomposes a group that is decomposed by the action of an acid to form a hydrophilic group such as a hydroxyl group or a carboxyl group. The solubility in the liquid is increased.

  As for the molecular weight of resin (A), 2000-50000 are preferable at a weight average, More preferably, it is 2000-30000. That is, the weight average molecular weight is preferably 2,000 or more from the viewpoint of the heat resistance of the resist, and is preferably 50,000 or less from the viewpoint of solubility in developer, sensitivity, and resolution.

  The dispersity (Mw / Mn) of the resin (A) is preferably 1.0 to 3.0, more preferably 1.1 to 2.0, and particularly preferably 1.1 to 1.8. It is. As a method for reducing the degree of dispersion, a polymer obtained by ordinary radical polymerization is dissolved in a good solvent, and then a poor solvent is added to remove components having a low molecular weight, or a living weight polymerization method such as a living radical polymerization method is used. There are methods based on legal methods, and any of them can be suitably used.

  As a living radical polymerization method, a method using a nitroxide by George et al., A method by Sawamoto using a metal complex, a method by Machaufsky et al., Etc. can be used.

  In addition, from the viewpoint of improving the roughness of the pattern, in the above normal radical polymerization method, the dropping polymerization method (when the monomer is radically polymerized in the presence of a radical polymerization initiator, the monomer is further continuously or intermittently formed. Application of radical polymerization method) is preferred.

  In the drop polymerization method, the type and composition of the monomer initially charged in the reaction vessel and the type and composition of the monomer added later during the progress of radical polymerization may be the same or different.

  In addition, it is preferable to use a method in which a polymerization initiator is further added together with a monomer to be added later, since it is possible to reduce unreacted monomers.

  The amount of the acid-decomposable resin is generally 50 to 99.5% by mass, preferably 80 to 99% by mass, more preferably 90 to 98% by mass, based on the total solid content of the composition. Is done.

[2] (B) Compound that generates acid upon irradiation with actinic rays or radiation
The compound (B) that generates an acid upon irradiation with actinic rays or radiation contained in the resist composition of the present invention (hereinafter sometimes referred to as “acid generator”) is generally used as an acid generator. Can be selected from among the existing compounds.
That is, known light (400 to 200 nm ultraviolet light, far-off light used for photoinitiators of photocationic polymerization, photoinitiators of photoradical polymerization, photodecolorants of dyes, photochromic agents, or micro-resists. UV, particularly preferably KrF excimer laser light), ArF excimer laser light, F ₂ excimer laser light, electron beam, X-ray or other active rays or compounds that generate an acid upon irradiation, and mixtures thereof. Can be 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 that generates an acid upon irradiation with these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, such as US Pat. No. 3,849,137, German Patent No. 3,914,407, JP 63-26653, JP 55-164824, JP 62-69263, JP 63-146038, JP 63-163452, JP 62-153853, JP 63- The compounds described in each specification such as 146029, gazettes and the like can be used.

  Furthermore, compounds capable of generating an acid by light described in the specifications of US Pat. No. 3,797,778 and European Patent No. 126712 can also be used.

  Of the compounds that can be decomposed by irradiation with actinic rays or radiation that can be used, 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).

Ar ¹ and Ar ² each independently represents an aryl group. Preferred substituents for the aryl group 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 ¹⁰¹ , R ¹⁰² and R ¹⁰³ 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 for the aryl group are an alkoxy 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. ˜8 alkoxy groups, carboxyl groups, and alkoxycarbonyl groups.

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 ¹⁰¹ , R ¹⁰² and R ¹⁰³ 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, for example, by the methods described in the specifications and publications of U.S. Pat. Nos. 2,807,648 and 4,247,473, JP-A-53-101331, etc. Can be synthesized.

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

Ar ³ and Ar ⁴ each independently represents an aryl group.
R ¹⁰⁴ 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) A diazodisulfone derivative represented by the following general formula (PAG7).

Here, R represents a linear, branched or cyclic alkyl 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 (PAG8) can also be used as the acid generator (B).

In general formula (PAG8),
R _{4 to} R ₈ represent a hydrogen atom, an alkyl group, an alkoxy group, a nitro group, a halogen atom, an alkyloxycarbonyl group or an aryl group, and at least two of R _{4 to} R ₈ are bonded to form a ring structure. It may be formed.
R ₉ and R ₁₀ represent a hydrogen atom, an alkyl group, a cyano group, or an aryl group.
Y ₁ and Y ₂ represent an alkyl group, an aryl group, an aralkyl group or an aromatic group containing a hetero atom, and Y ₁ and Y ₂ may be bonded to form a ring.
Y ₃ represents a single bond or a divalent linking group.
X ⁻ represents a non-nucleophilic anion.
At least one of R ₄ to R ₈ and at least one of Y ₁ or Y ₂ may be bonded to form a ring, or at least one of R ₄ to R ₈ and at least one of R ₉ or R ₁₀ may be bonded. To form a ring.
It may be bonded via a linking group at any position of R ₄ to R ₁₀ , or at any position of Y ₁ or Y ₂ , and may have two or more structures of the formula (PAG8).

  Specific examples of the compound represented by the above formula (PAG8) are shown below, but the present invention is not limited thereto.

  Among the above-mentioned compounds that decompose upon irradiation with actinic rays or radiation to generate an acid, 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.

  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 solid content of the resist composition.

[3] Organic basic compound In the composition of the present invention, performance variation (e.g., pattern T-top shape formation, sensitivity variation, pattern line width variation) over time after irradiation with actinic rays or radiation and before heat treatment, It is preferable to add an organic basic compound for the purpose of preventing performance fluctuations with time after coating, and further, after irradiation with actinic rays or radiation, excessive diffusion of acid (deterioration of resolution) during heat treatment. The organic basic compound is, for example, an organic basic compound containing basic nitrogen, and a compound having a pKa value of 4 or more of the conjugate acid is preferably used.
For example, the compound which has a structure of following formula (A)-(E) can be mentioned.

Here, R ²⁰⁰ , R ^201, and R ²⁰² may be the same or different, and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, or 6 to 20 carbon atoms. Wherein R ²⁰¹ and R ²⁰² may be bonded to each other to form a ring.
The alkyl group may be unsubstituted or may have a substituent. Examples of the alkyl group having a substituent include an aminoalkyl group having 1 to 6 carbon atoms and a hydroxyalkyl group having 1 to 6 carbon atoms. preferable.
R ²⁰³ , R ²⁰⁴ , R ²⁰⁵ and R ²⁰⁶ may be the same or different and each represents an alkyl group having 1 to 6 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 guanidine, aminopyridine, aminoalkylpyridine, aminopyrrolidine, indazole, imidazole, pyrazole, pyrazine, pyrimidine, purine, imidazoline, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine and the like. These may have a substituent, and preferred examples of the substituent include an amino group, an alkyl group, an alkoxy group, an acyl group, an acyloxy group, an aryl group, an aryloxy group, a nitro group, a hydroxyl group, and a cyano group. It is done.

  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) -5-methylpyrazine, pyrimidine, 2,4-diaminopyrimidine, 4,6-dihydroxypyrimidine, 2-pyrazoline, 3-pyrazoline, N-aminomorpholine, N- Examples include (2-aminoethyl) morpholine, but are not limited thereto.
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. In other words, the molar ratio is preferably 2.5 or more from the viewpoint of sensitivity and resolution, and is preferably 300 or less from the viewpoint of suppressing the reduction in resolution due to the thickening of the resist pattern over time until post-exposure heat treatment. The acid generator / organic basic compound (molar ratio) is more preferably 5.0 to 200, still more preferably 7.0 to 150.

[4] Surfactant The composition of the present invention preferably contains a surfactant, particularly a fluorine-based and / or silicon-based surfactant. That is, the composition of the present invention preferably contains any one or two or more of fluorine-based surfactants, silicon-based surfactants, and surfactants containing both fluorine atoms and silicon atoms. The addition of these fluorine-based and / or silicon-based surfactants is effective in suppressing development defects and improving coating properties.

As these fluorine-based and / or silicon-based surfactants, for example, JP-A-62-36663, JP-A-61-226746, JP-A-61-226745, JP-A-62-170950 are disclosed. JP-A-63-34540, JP-A-7-230165, JP-A-8-62834, JP-A-9-54432, JP-A-9-5988, JP-A-2002-277862, US Pat. 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 The following commercially available surfactants can also be used as they are.
Examples of commercially available fluorine-based and / or silicon-based surfactants that can be used include F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Fluorad 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) Fluorine-based surfactants or silicon-based surfactants such as those manufactured by K.K. 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 shown above, fluorine-based and / or silicon-based surfactants can be produced by a telomerization method (also referred to as a telomer method) or an oligomerization method (also referred to as an oligomer method). A surfactant using a polymer having a fluoroaliphatic group derived from a fluoroaliphatic compound 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).

For example, as a commercially available fluorine-based and / or silicon-based surfactant, Megafac F178, F-470, F-473, F-475, F-476, F-472 (manufactured by Dainippon Ink & Chemicals, Inc.) Can be mentioned. Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxy) (Ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate) copolymer, acrylate (or methacrylate) and (poly (oxyalkylene)) acrylate having C ₈ F ₁₇ groups (or Copolymer of acrylate (or methacrylate), (poly (oxyethylene)) acrylate (or methacrylate), and (poly (oxypropylene)) acrylate (or methacrylate) having a C ₈ F ₁₇ group Coalesce, etc. Can.

  The amount of the fluorine-based and / or silicon-based surfactant used is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, based on the total amount of the positive resist composition (excluding the solvent). Especially preferably, it is 0.01 mass%-1 mass%.

[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. As the solvent used here, 3-methoxy-1-butanol, 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 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 and tetrahydrofuran. These solvents are used alone or in combination.

  In the present invention, as a solvent, propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate and propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether and propylene glycol monoethyl ether, or methyl lactate and ethyl lactate. It is preferable to use a mixed solvent obtained by mixing alkyl lactates such as the above.

  The solid content concentration when each of the above components is dissolved in a solvent is preferably 3 to 15% by mass, and more preferably 5 to 10% by mass.

[6] Non-polymeric dissolution inhibitor The positive resist composition of the present invention preferably further contains a dissolution inhibitor from the viewpoint of sensitivity and contrast. Here, the non-polymer type dissolution inhibitor is a compound having at least one acid-decomposable group having a molecular weight of 10,000 or less, preferably a compound having a molecular weight of 1000 to 5000, which increases the solubility in an alkali developer by the action of an acid. is there. Here, examples of the acid-decomposable group include those in the resin (A).
From the viewpoint of transparency to the F ₂ excimer laser, a fluorine atom is preferably substituted in the mother nucleus (site other than the acid-decomposable group).
3-50 mass% is preferable with respect to resin in a composition, as for the addition amount, More preferably, it is 5-40 mass%, More preferably, it is 7-30 mass%.

  Specific examples of the non-polymer type dissolution inhibitor are listed below, but are not limited thereto.

In the manufacture of precision integrated circuit elements, the pattern forming process on the resist film is performed by applying the 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). , dried, to form a resist film, then KrF, ArF, perform irradiation with actinic rays or radiation such as F ₂ excimer laser light, preferably heated, form a good resist pattern development, rinsing, and then dried can do.

Examples of the alkaline developer used for development include inorganic alkalis 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, alcoholamines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, An aqueous solution of an alkali such as a quaternary ammonium salt such as choline or a cyclic amine such as pyrrole or piperidine 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 developers, quaternary ammonium salts are preferable, and tetramethylammonium hydroxide and choline are more preferable.
The alkali concentration of the alkali developer is usually from 0.1 to 20% by mass, and the pH is usually from 10.0 to 15.0.
〔Example〕

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

Synthesis Example 1 (Synthesis of Resin (F-1))
3- (5-bicyclo [2.2.1] hepten-2-yl) -1,1,1-trifluoro-2- (trifluoromethyl) -2-propan-2-ol, 27.4 g, methylacrylic After dissolving 5.2 g of acid methoxymethyl ester and 14.0 g of α-trifluoromethylacrylic acid t-butyl ester in 200 ml of THF, 0.5 g of azo polymerization initiator V-65 (manufactured by Wako Pure Chemical Industries, Ltd.) Was added and stirred at 70 ° C. for 10 hours for reaction.
After adding 500 ml of hexane to the reaction solution to precipitate a polymer, the upper layer was removed by decantation. The remaining viscous polymer was dissolved in 100 ml of acetone, and 1 liter of hexane was added again to separate the polymer to remove unreacted monomer and oligomer components. When the molecular weight of the obtained polymer was measured by GPC, the weight average molecular weight was 10,000 and the dispersity was 2.0.
This polymer was dissolved again in 100 ml of acetone, and 1 liter of hexane was added again, whereby the resin (F-1) was fractionated to remove unreacted monomers and oligomer components. When the molecular weight of the obtained resin (F-1) was measured by GPC, the weight average molecular weight was 11000, and the degree of dispersion was 1.4.

Synthesis of Resin (F-3, 5, 7, 10, 12, 14) and Comparative Resin (C-1, 2) Resin (F-3, 5, 7, 10, 12, 14) and the following comparative resins (C-1, 2) were obtained.
Table 1 below collectively shows the molar composition ratio, weight average molecular weight, and degree of dispersion of the resin (F-1, 3, 5, 7, 10, 12, 14) and the comparative resin (C-1, 2).

<Resist evaluation>
Resin shown in Table 2 below: 1.2 g, acid generator: 0.030 g, organic basic compound: 0.0012 g, surfactant: 100 ppm with respect to the resin solution, sometimes non-polymer type dissolution inhibitor: 0. A resin solution in which 24 g was dissolved in 19.6 g of a solvent was filtered through a 0.1 μm polytetrafluoroethylene filter to prepare a positive resist solution.
The positive resist solution prepared as described above is applied to a silicon wafer that has been subjected to hexamethyldisilazane treatment by a spin coater, and is heated and dried on a vacuum contact hot plate at 115 ° C. for 90 seconds, thereby forming a resist film having a thickness of 100 nm. Got.

[Sensitivity fluctuation rate]
The obtained resist film was exposed using a 157 nm laser exposure / dissolution behavior analyzer VUVES-4500 (manufactured by RISOTEC Japan), and immediately after the exposure, it was heated on a hot plate at 120 ° C. for 90 seconds. The sample was developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution for 60 seconds and rinsed with pure water to obtain a sample wafer. For these, an exposure amount (sensitivity) D1 at which a large pattern (1.5 mm × 1.5 mm square) was resolved was determined. Further, an exposure amount (sensitivity) D2 at which a large pattern is resolved was determined by performing the same operation except that the film was heated at 125 ° C. for 90 seconds immediately after exposure. The sensitivity fluctuation rate due to the change in post-heating temperature (PEB temperature) was determined by the following formula. The smaller the absolute value, the smaller the performance change due to post-heating temperature change.
Sensitivity fluctuation rate (%) = {(D1-D2) / D1} × 100

[PEB temperature dependence]
First, ARC-29A-8 manufactured by Brewer Science Co., Ltd. was applied to a silicon wafer at 78 nm using a spin coater, dried, and then the positive photoresist composition obtained was applied thereon, and the resultant was applied at 115 ° C. for 90 seconds. It dried and produced about 0.3 micrometer positive type photoresist film. Next, using an ArF excimer laser (ArF stepper manufactured by ISI with a wavelength of 193 nm and NA = 0.6), an isolated contact hole pattern with a mask size of 180 nm with an exposure amount that reproduces the isolated contact hole with a mask size of 180 nm to 140 nm. And post-exposure heating (PEB) was performed at two temperatures of 120 ° C. + 2 ° C. and −2 ° C. for 90 seconds. Each of the obtained contact hole patterns was measured, and their diameters L ₁ and L ₂ were determined. The PEB temperature dependency was defined as a change in diameter per 1 ° C. PEB temperature change, and was calculated by the following formula.
PEB temperature dependency (nm / ° C.) = | L ₁ −L ₂ | / 4

  The results are shown in Table 2.

The contents of the symbols in Table 2 are as follows.
N-1: Hexamethylenetetramine N-2: 1,5-diazabicyclo [4.3.0] -5-nonene N-3: 1,8-diazabicyclo [5.4.0] -7-undecene W-1 : Megafuck F176 (Dainippon Ink Chemical Co., Ltd.) (Fluorine)
W-2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.) (fluorine and silicon)
S-1: Ethyl lactate S-2: Propylene glycol monomethyl ether acetate S-3: Propylene glycol monomethyl ether The acid generator and dissolution inhibitor are those exemplified above.

  From Table 2, it is clear that the positive resist composition of the present invention is excellent in PEB temperature characteristics and sensitivity fluctuation rate.

[Resolution]
The positive resist solutions of Examples 1, 4, 6 and Comparative Example 1 were evenly coated on a silicon wafer coated with an antireflection film (manufactured by DUV42-6 Brewer Science. Ine.) Using a spin coater. Heat drying was performed at 60 ° C. for 60 seconds to form a positive resist film having a thickness of 0.12 μm. The resist film was subjected to pattern exposure using an F ₂ microstepper, and immediately after the exposure, it was heated on a hot plate at 110 ° C. for 90 seconds. Further, the resist film was developed with an aqueous 2.38 mass% tetramethylammonium hydroxide solution at 23 ° C. for 30 seconds, rinsed with pure water for 30 seconds, and then dried. With respect to the pattern on the silicon wafer thus obtained, the resolution performance was evaluated with a limit resolution that can be reproduced with a minimum exposure amount that reproduces a line and space of 100 nm.

  The evaluation results are shown in Table 3 below.

  From Table 3, it is clear that the positive resist composition of the present invention has high resolution.

Claims (5)

(A) A group that decomposes by the action of an acid represented by formula (Z1) to increase the solubility in an alkali developer and an alkali developer that decomposes by the action of an acid represented by formula (Z2) A resin having at least two different groups selected from groups that increase solubility in water and containing a fluorine atom, and
(B) A positive resist composition comprising a compound that generates an acid upon irradiation with actinic rays or radiation.

In general formula (Z1) or (Z2), R _{1z to} R _3z and R _5z each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, or an aryl group. R _4z represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. However, any two of R _1z , R _2z and R _3z , and R _4z and R _5z may be bonded to form a ring.   The positive resist composition according to claim 1, wherein the resin of component (A) further has an alicyclic hydrocarbon structure. The resin as component (A) further has at least one repeating unit formed by a compound substituted with a group represented by the following general formula (Y). Positive resist composition.

In general formula (Y), L ₁ represents a single bond or a methylene group. R _{1 to} R ₆ each independently represents a fluorine atom or a hydrogen atom. However, at least one of R _{1 to} R ₆ is a fluorine atom. One of R _{1 to} R ₆ may be connected to the main chain of the polymer via a carbon chain to form a ring. R ₄ may be bonded to the α carbon atom of the hydroxyl group to form a ring.   The positive resist composition according to claim 1, wherein the resin of component (A) further has an alicyclic hydrocarbon structure in the main chain.   A pattern forming method comprising: forming a resist film from the resist composition according to claim 1; and exposing and developing the resist film.