JP2005099327A - Positive resist composition and method for forming pattern by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive photoresist composition for improving the performance of essential micro-photofabrication using far UV light, in particular, ArF excimer laser light, and also to provide a positive photoresist composition for exposure to far UV rays which suppresses pattern collapse or LER (line edge roughness). <P>SOLUTION: The positive resist composition contains: (A) a resin having a repeating unit (A1) having an alicyclic lactone structure, a repeating unit (A2) containing a specified structure, and a repeating unit (A3) having a group which is decomposed by the effect of an acid, with the solubility rate of the resin with an alkaline developing solution increased by the effect of an acid; (B) a compound which generates an acid by irradiation of active rays or radiation; and (C) solvent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a positive photoresist composition for microfabrication of semiconductor elements and the like that is sensitive to deep ultraviolet rays, and more particularly to a positive photoresist composition for deep ultraviolet exposure.

In recent years, the degree of integration of integrated circuits has been increasing, and in the manufacture of semiconductor substrates such as VLSI, processing of ultra-fine patterns having a line width of less than half a micron has been required. In order to satisfy this need, the wavelength used by exposure apparatuses used in photolithography has become increasingly shorter, and now it is considered to use excimer laser light (XeCl, KrF, ArF, etc.) having a short wavelength among far ultraviolet rays. It is becoming.
A chemical amplification type resist is used for lithography pattern formation in this wavelength region.

  As a photoresist composition for an ArF light source, a resin having an alicyclic hydrocarbon moiety introduced therein has been proposed for the purpose of imparting dry etching resistance.

For example, Patent Document 1 (Japanese Patent Laid-Open No. 11-109632) discloses a resin having a hydroxyadamantane structure, Patent Document 2 (Japanese Patent Laid-Open No. 2000-26446), Patent Document 3 (Japanese Patent Laid-Open No. 2000-159758), Patent Document 4 (Japanese Patent Laid-Open No. 2001-242627) and Non-Patent Document 1 (J. Photopolym. Sci. Technol., 12 (3), 487 (1999)) are resins having a norbornane lactone structure, Patent Document 5 JP 2000-122294), Patent Document 6 (Japanese Patent Laid-Open No. 2001-188351), and Non-Patent Document 2 (Proc. SPIE, 3999, 1147 (2000)) are resins having an adamantane lactone structure, Patent Document 7 ( JP 2001-109154 A) discloses a resin having a hydroxyadamantane structure and a norbornane lactone structure.
In addition, a resist composition including a resin containing an acrylic monomer is disclosed in Patent Document 8 (Japanese Patent Laid-Open No. 2003-43690), Patent Document 9 (Japanese Patent Laid-Open No. 2002-6501), and Patent Document 10 (Japanese Patent Laid-Open No. 2002-2002). -155118).

  In general, the resin containing an acid-decomposable group used for the photoresist for exposure to far ultraviolet rays as described above contains an aliphatic cyclic hydrocarbon group in the molecule at the same time. The above technique is still insufficient in terms of pattern collapse and LER (line edge roughness), and improvement is desired.

JP-A-11-109632 JP 2000-26446 A JP 2000-159758 A JP 2001-242627 A JP 2000-122294 A JP 2001-188351 A JP 2001-109154 A JP 2003-43690 A Japanese Patent Laid-Open No. 2002-6501 JP 2002-155118 A Journal of Photopolymer Science Technology (J. Photopolym. Sci. Technol.), 1999, Vol. 12, No. 5, p. 487 Proc. SPIE, 2000, 3999, 1147

  An object of the present invention is to provide a positive-type photoresist composition that solves the problems in the technology for improving the original performance of microphotofabrication using far-ultraviolet light, particularly ArF excimer laser light. An object of the present invention is to provide a positive photoresist composition for deep ultraviolet exposure that can suppress pattern collapse and LER (line edge roughness).

  As a result of intensive investigations on the constituent materials of the positive chemically amplified resist composition, the inventors have found that the object of the present invention can be achieved by the following constitution, and have reached the present invention.

(1) Repeating unit (A1) represented by the following formula (A-1), repeating unit (A2) represented by the following formula (A-2), and repeating represented by the following formula (A-3) A resin (A) containing a unit (A3), which increases the dissolution rate in an alkaline developer by the action of an acid, a compound (B) which generates an acid upon irradiation with actinic rays or radiation, and a solvent (C) Containing a positive resist composition.

In general formulas (A-1), (A-2) and (A-3),
R _{1a to} R _3a each independently represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group. However, at least one of R _{1a to} R _{3a represents} a fluorine atom or an alkyl group substituted with at least one fluorine atom.
Ring A represents a cyclic lactone structure.
p represents an integer of 1 to 4.
G represents a fluorine atom, a chlorine atom, a hydroxyl group, a cyano group, an alkyl group or an alkoxy group.
ALG represents an acid-decomposable group.

(2) The ring A of the repeating unit (A1) of the resin (A) is a repeating unit having a norbornane lactone structure represented by the following general formulas (a-1) to (a-3). The positive resist composition as described in (1).

In General Formulas (a-1) to (a-3), R _{1 to} R ₆ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, or an alkenyl group. Two of R _{1 to} R ₅ may combine to form a ring.

(3) The positive type according to (1) or (2), wherein ALG in the repeating unit (A3) of the resin (A) represents one of the following general formulas (pI) or (pII) Resist composition.

In the formula, R ₁₁ represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or a sec-butyl group, and Z forms an alicyclic hydrocarbon group together with a carbon atom. Represents the atomic group necessary to do.
R _{12 to} R ₁₄ each independently represents an alkyl group having 1 to 4 carbon atoms or an alicyclic hydrocarbon group. However, at least one of R _{12 to} R ₁₄ represents an alicyclic hydrocarbon group.

(4) The copolymerization ratio of the repeating units (A1), (A2) and (A3) of the resin (A) is mol%, and (A1) / (A2) / (A3) = 30-50 / 10-30 The positive resist composition as described in any one of (1) to (3), which is / 30 to 50.

(5) Any one of R _{1a to} R _3a in the repeating units (A1) to (A3) of the resin (A) is a fluorine atom or an alkyl group substituted with at least one fluorine atom, and the rest The positive resist composition as described in any one of (1) to (4), wherein the two are groups not containing a fluorine atom.

(6) A pattern forming method comprising: forming a resist film on a semiconductor substrate using the resist composition according to any one of (1) to (5) above; and exposing and developing the resist film. .

  According to the present invention, a positive resist composition capable of suppressing pattern collapse and LER (line edge roughness) can be obtained.

Hereinafter, the components used in 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.

In the present invention, in the notation of a group (atomic group), when substituted or unsubstituted is not particularly described, both substituted and unsubstituted are included. For example, when it is simply described as “alkyl group”, it may be an unsubstituted alkyl or an alkyl group having a substituent.
[1] Resin that increases the dissolution rate in an alkaline developer by the action of an acid (component A)
The resin (resin (A)) whose dissolution rate in an alkaline developer is increased by the action of an acid in the present invention has a lactone structure and is represented by the following repeating unit (A1) represented by the following formula (A-1): It contains a repeating unit (A2) represented by (A-2) and a repeating unit (A3) represented by the following formula (A-3) having a group capable of decomposing by the action of an acid.

In general formulas (A-1), (A-2) and (A-3),
R _{1a to} R _3a each independently represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group. However, at least one of R _{1 to} R _{3 represents} a fluorine atom or an alkyl group substituted with at least one fluorine atom. Moreover, it is preferable that the remaining two are groups which do not contain a fluorine atom.
Ring A represents a cyclic lactone structure.
p represents an integer of 1 to 4.
G represents a fluorine atom, a chlorine atom, a hydroxyl group, a cyano group, an alkyl group or an alkoxy group. The p G may be bonded on the carbon forming the adamantane alicyclic structure or may be bonded via a substituent substituted on the adamantane alicyclic structure.
ALG represents an acid-decomposable group.

At least one of R _{1 to} R _{3 represents} a fluorine atom or an alkyl group substituted with at least one fluorine atom. More preferably, one or two of R _{1 to} R ₃ are a fluorine atom or at least 1 An alkyl group substituted with one fluorine atom.
The alkyl group as R _{1a to} R _3a is preferably a linear or branched alkyl group which may be substituted with a fluorine atom. The linear or branched alkyl group is preferably an alkyl group having 1 to 3 carbon atoms, and examples thereof include a methyl group and a trifluoromethyl group.

(A1) Repeating Unit Having Lactone Structure The resin (A) of the present invention has a lactone structure and contains a repeating unit (A1) represented by the following formula (A-1).

  Examples of the repeating unit (A-1) having a lactone structure include those having an alicyclic lactone structure, and examples thereof include a repeating unit having cyclohexanelactone, norbornanelactone, or adamantanelactone.

For example, as the repeating unit having norbornane lactone, the repeating unit having groups represented by the following general formulas (a-1) to (a-3), and the repeating unit having cyclohexanelactone as the repeating unit (a-4) ) And the repeating unit having a group represented by (a-5) and the repeating unit having an adamantane lactone can include a repeating unit having a group represented by formula (A1-2).
In addition, it is especially preferable that the ring A in the general formula (A-1) is a group represented by any one of the following general formulas (a-1) to (a-3).

In the general formulas (a-1) to (a-5), R _{1 to} R ₆ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, or —COORa. Here, Ra represents an alkyl group. Two of R _{1 to} R ₆ may combine to form a ring. Represents. Two of R _{1 to} R ₆ may combine to form a ring.
In addition, about each of R < ₁ > -R < ₆ >, the case where it is a hydrogen atom means that it is unsubstituted. For example, the cyclic structure in the general formula (a-1) may have a maximum of five substituents (alkyl group, cycloalkyl group, or alkenyl group) as R _{1 to} R ₅ .

The alkyl group as R _{1 to} R ₆ and Ra may have a substituent and is a linear or branched alkyl group.
The linear or branched alkyl group 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, still more preferably a methyl group, An ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group.

The cycloalkyl group as R _{1 to} R ₆ may have a substituent, and those having 3 to 8 carbon atoms, such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. preferable.
The alkenyl group as R _{1 to} R ₆ may have a substituent, and those having 2 to 6 carbon atoms such as vinyl group, propenyl group, butenyl group and hexenyl group are preferable.
Examples of the ring formed by combining two of R _{1 to} R ₆ include 3- to 8-membered rings such as cyclopropane ring, cyclobutane ring, cyclopentane ring, cyclohexane ring, and cyclooctane ring.
In the general formulas (a-1) to (a-5), R _{1 to} R ₆ may be connected to any carbon atom constituting the cyclic skeleton.

  Moreover, as a preferable substituent which the said alkyl group, a cycloalkyl group, and an alkenyl group may have, a C1-C4 alkoxy group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), Examples thereof include an acyl group having 2 to 5 carbon atoms, an acyloxy group having 2 to 5 carbon atoms, a cyano group, a hydroxyl group, a carboxy group, an alkoxycarbonyl group having 2 to 5 carbon atoms, and a nitro group.

  Examples of the repeating unit having a group represented by general formulas (a-1) to (a-5) include a repeating unit represented by general formula (A1-1).

In general formula (A1-1),
L represents a single bond, an ether group, an ester group, a carbonyl group, an alkylene group, or a divalent group obtained by combining these.
A represents a group represented by any one of the general formulas (a-1) to (a-5).
In L, examples of the combined divalent group include those represented by the following formulae.

In the above formula, R _ab and R _bb represent a hydrogen atom, an alkyl group, a substituted alkyl group, a halogen atom, a hydroxyl group, and an alkoxy group, and both may be the same or different.
The alkyl group is preferably a lower alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, or a butyl group, and more preferably selected from a methyl group, an ethyl group, a propyl group, and an isopropyl group. Examples of the substituent of the substituted alkyl group include a hydroxyl group, a halogen atom, and an alkoxy group having 1 to 4 carbon atoms.
Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.
Examples of the halogen atom include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom.
r1 represents an integer of 1 to 10, preferably an integer of 1 to 4. m represents an integer of 1 to 3, preferably 1 or 2.

  Specific examples of the repeating unit represented by formula (A1-1) are shown below, but the contents of the present invention are not limited thereto.

  As the repeating unit having adamantane lactone, the repeating unit represented by General Formula (A1-2) can be given.

In the general formula (A1-2), L ₂ represents a single bond, an alkylene group, a cycloalkylene group, an ether group, a thioether group, a carbonyl group, or an ester group, alone or in combination of two or more groups. Represent.

Examples of the alkylene group represented by L ₂ include groups represented by the following formulae.
-[C (Rnf) (Rng)] r-
In the above formula, Rnf and Rng represent a hydrogen atom, an alkyl group, a substituted alkyl group, a halogen atom, a hydroxyl group, and an alkoxy group, and both may be the same or different.
The alkyl group is preferably a lower alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, or a butyl group, and more preferably selected from a methyl group, an ethyl group, a propyl group, and an isopropyl group. Examples of the substituent of the substituted alkyl group include a hydroxyl group, a halogen atom, and an alkoxy group. Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Examples of the halogen atom include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom. r is an integer of 1-10.

Examples of the cycloalkylene group represented by L ₂ include those having 3 to 10 carbon atoms, such as a cyclopentylene group, a cyclohexylene group, and a cyclooctylene group.

The bridged alicyclic ring containing Z ₂ may have a substituent. Examples of the substituent include a halogen atom, an alkoxy group (preferably having 1 to 4 carbon atoms), an alkoxycarbonyl group (preferably having 1 to 5 carbon atoms), an acyl group (for example, a formyl group and a benzoyl group), an acyloxy group ( Examples thereof include a propylcarbonyloxy group, a benzoyloxy group), an alkyl group (preferably having 1 to 4 carbon atoms), a carboxyl group, a hydroxyl group, and an alkylsulfonylsulfamoyl group (such as —CONHSO ₂ CH ₃ ). In addition, the alkyl group as a substituent may be further substituted with a hydroxyl group, a halogen atom, an alkoxy group (preferably having 1 to 4 carbon atoms), or the like.

In general formula (A1-2), the oxygen atom of the ester group bonded to L ₂ may be bonded at any position of the carbon atom constituting the bridged alicyclic ring structure containing Z _2. .

  Specific examples of the repeating unit represented by the general formula (A1-2) are shown below, but are not limited thereto.

  Moreover, the repeating unit (A1) can also contain a repeating unit having a lactone structure represented by the following general formula (IV).

In general formula (IV),
W ₁ represents a single bond, an alkylene group, an ether group, a thioether group, a carbonyl group, or a group of two or more groups selected from the group consisting of an ester group.
R _a1 , R _b1 , R _c1 , R _d1 and R _e1 each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. m and n each independently represents an integer of 0 to 3, and m + n is 2 or more and 6 or less.

_Examples of the alkyl group having 1 to 4 carbon atoms of R _{a1 to} R _e1 include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group and the like. Can do.

In the general formula (IV), examples of the alkylene group represented by W ₁ include groups represented by the following formulae.
− [C (Rf) (Rg)] r ₁ −
In the above formula, Rf and Rg represent a hydrogen atom, an alkyl group, a substituted alkyl group, a halogen atom, a hydroxyl group, or an alkoxy group, and both may be the same or different.
The alkyl group is preferably a lower alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, or a butyl group, and more preferably selected from a methyl group, an ethyl group, a propyl group, and an isopropyl group. Examples of the substituent of the substituted alkyl group include a hydroxyl group, a halogen atom, and an alkoxy group.
Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.
Examples of the halogen atom include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom.
r ₁ is an integer of 1 to 10.

Examples of further substituents in the alkyl group include a carboxyl group, an acyloxy group, a cyano group, an alkyl group, a substituted alkyl group, a halogen atom, a hydroxyl group, an alkoxy group, a substituted alkoxy group, an acetylamide group, an alkoxycarbonyl group, and an acyl group. Can be mentioned.
Examples of the alkyl group include lower alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. Examples of the substituent of the substituted alkyl group include a hydroxyl group, a halogen atom, and an alkoxy group. Examples of the substituent of the substituted alkoxy group include an alkoxy group. Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Examples of the acyloxy group include an acetoxy group. Examples of the halogen atom include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom.

  Hereinafter, although the specific example of the monomer corresponding to the repeating unit shown by general formula (IV) is shown, it is not limited to these.

(A2) Repeating unit represented by formula (A-2) Next, the repeating unit (A2) represented by formula (A-2) will be described.
Examples of the alkyl group of G in the formula (A-2) include linear or branched alkyl groups which may have a substituent, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group. A lower alkyl group is preferred, and more preferably selected from a methyl group, an ethyl group, a propyl group, and an isopropyl group. Examples of the substituent that may have include a hydroxyl group, a halogen atom, and an alkoxy group having 1 to 4 carbon atoms.
Examples of the alkoxy group of G include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.

  General Formula The repeating unit represented by the general formula (A-2) is preferably a repeating unit represented by the following general formula (A2).

In general formula (A2), R _{6 to} R ₈ each independently represents a hydrogen atom, a hydroxyl group or an alkyl group, provided that at least one represents a hydroxyl group.

In the repeating unit represented by the general formula (A2), it is more preferable that two of R _{6 to} R ₈ are hydroxyl groups.

  Although the specific example of the repeating unit represented by general formula (A2) below is given, it is not limited to these.

(A3) Repeating unit having a group decomposable by the action of an acid The resin (A) of the present invention is a resin (acid-decomposable resin) whose dissolution rate in an alkaline developer is increased by the action of an acid. It contains a repeating unit (acid-decomposable group) having a group that decomposes and becomes alkali-soluble.

  The resin (A) of the present invention contains a repeating unit represented by the above general formula (A-3), but the acid decomposable group is represented by the above general formula (A-1), or You may have in the repeating unit represented by (A-2), and you may contain in another repeating unit.

  As the repeating unit having an acid-decomposable group, the repeating unit represented by the general formula (A-3) is contained.

Examples of the acid-decomposable group include groups represented by -COOA ⁰ and -O-B ⁰ groups. Further Examples of the group containing these, include groups represented by -R ⁰ -COOA ^0, or -A _r -O-B ^0.
Here, A ⁰ is -C (R ⁰¹ ) (R ⁰² ) (R ⁰³ ), -Si (R ⁰¹ ) (R ⁰² ) (R ⁰³ ), -C (R ⁰⁴ ) (R ⁰⁵ ) -O-R ⁰⁶ group or lactone group. B ⁰ represents —A ⁰ or —CO—O—A ⁰ group.
^{R 01, R 02, R 03} , R 04 and R ⁰⁵ may also be different from, and each of the same, represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group, R ⁰⁶ Represents an alkyl group, a cyclic alkyl group or an aryl group. However, at least two of R ^{01 to} R ⁰³ are groups other than hydrogen atoms, and two groups of R ^{01 to} R ⁰³ and R ^{04 to} R ⁰⁶ are bonded to form a ring. Also good. A ⁰ represents a single bond or a divalent or higher aliphatic or aromatic hydrocarbon group which may have a substituent, and —Ar— may have a monocyclic or polycyclic substituent. An aromatic group having a valence of 2 or more is shown.

  Here, the alkyl group is preferably an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, or a t-butyl group. Those having 3 to 30 carbon atoms such as propyl group, cyclobutyl group, cyclohexyl group and adamantyl group are preferred, and the alkenyl group has 2 to 4 carbon atoms such as vinyl group, propenyl group, allyl group and butenyl group. Those having 6 to 14 carbon atoms such as phenyl, xylyl, toluyl, cumenyl, naphthyl, and anthracenyl groups are preferable. Examples of the cyclic alkyl group include those having 3 to 30 carbon atoms, specifically, cyclopropyl group, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group, boronyl group, tricyclodecanyl group, Examples include a cyclopentenyl group, a nobornane epoxy group, a menthyl group, an isomenthyl group, a neomenthyl group, a tetracyclododecanyl group, and a steroid residue. Examples of the aralkyl group include those having 7 to 20 carbon atoms, which may have a substituent. Examples include a benzyl group, a phenethyl group, and a cumyl group.

Substituents include hydroxyl groups, halogen atoms (fluorine, chlorine, bromine, iodine), nitro groups, cyano groups, the above alkyl groups, methoxy groups, ethoxy groups, hydroxyethoxy groups, propoxy groups, hydroxypropoxy groups, n -Alkoxy groups such as butoxy group, isobutoxy group, sec-butoxy group, t-butoxy group, alkoxycarbonyl groups such as methoxycarbonyl group, ethoxycarbonyl group, aralkyl groups such as benzyl group, phenethyl group, cumyl group, and aralkyloxy groups Acyl group such as formyl group, acetyl group, butyryl group, benzoyl group, cyanamyl group, valeryl group, acyloxy group such as butyryloxy group, alkenyl group, alkenyl such as vinyloxy group, propenyloxy group, allyloxy group, butenyloxy group, etc. Oxy group, allee above It can be exemplified group, an aryloxy group such as phenoxy group, aryloxycarbonyl group such as benzoyloxy group.
Examples of the lactone group include those having the following structure.

In the above formula, R ^a , R ^b and R ^c each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. n represents an integer of 2 to 4.

When an ArF excimer laser is used as a light source for exposure, it is preferable to use a group represented by —C (═O) —X ₁ —R ₀ as a group that is decomposed by the action of an acid. Here, as R ₀ , tertiary alkyl groups such as t-butyl group and t-amyl group, isobornyl group, 1-ethoxyethyl group, 1-butoxyethyl group, 1-isobutoxyethyl group, 1-cyclohexyloxy 1-alkoxyethyl group such as ethyl group, 1-methoxymethyl group, alkoxymethyl group such as 1-ethoxymethyl group, tetrahydropyranyl group, tetrahydrofuranyl group, trialkylsilyl group, 3-oxocyclohexyl group, the above lactone group Etc. X ₁ represents an oxygen atom or a sulfur atom, preferably an oxygen atom.

  In General Formula (A-3), ALG is preferably a group containing an alicyclic hydrocarbon represented by General Formula (pI) or (pII). More preferably, ALG is a group containing an alicyclic hydrocarbon represented by the general formula (pII).

In the formula, R ₁₁ represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or a sec-butyl group, and Z forms an alicyclic hydrocarbon group together with a carbon atom. Represents the atomic group necessary to do.
R _{12 to} R ₁₄ each independently represents an alkyl group having 1 to 4 carbon atoms or an alicyclic hydrocarbon group. However, at least one of R _{12 to} R ₁₄ represents an alicyclic hydrocarbon group.

In the general formula (pI) or (pII), the alkyl group in R _{12 to} R ₁₄ may be substituted or unsubstituted, and is a linear or branched alkyl group having 1 to 4 carbon atoms. Represents. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group.
Examples of the substituent that the alkyl group may have include, for example, an alkoxy group having 1 to 4 carbon atoms, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an acyl group, an acyloxy group, A cyano group, a hydroxyl group, a carboxy group, an alkoxycarbonyl group, a nitro group, etc. can be mentioned.

The alicyclic hydrocarbon group in R _{11 to} R _{14 or} the alicyclic hydrocarbon group formed by Z and a carbon atom may be monocyclic or polycyclic. Specific examples include groups having a monocyclo, bicyclo, tricyclo, tetracyclo structure or the like having 5 or more carbon atoms. The carbon number is preferably 6-30, and particularly preferably 7-25. These alicyclic hydrocarbon groups may have a substituent.
Below, the structural example of an alicyclic part is shown among alicyclic hydrocarbon groups.

  Preferred examples of the alicyclic moiety include an adamantyl group, a noradamantyl group, a decalin residue, a tricyclodecanyl group, a tetracyclododecanyl group, a norbornyl group, a cedrol group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, A cyclodecanyl group and a cyclododecanyl group can be mentioned. More preferred are an adamantyl group, a decalin residue, a norbornyl group, a cedrol group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecanyl group, a cyclododecanyl group, and a tricyclodecanyl group.

Examples of the substituent for these alicyclic hydrocarbon groups include an alkyl group, a substituted alkyl group, a halogen atom, a hydroxyl group, an alkoxy group, a carboxyl group, and an alkoxycarbonyl group.
The alkyl group is preferably a lower alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, or a butyl group, and more preferably a substituent selected from the group consisting of a methyl group, an ethyl group, a propyl group, and an isopropyl group. Represent.
Examples of the substituent of the substituted alkyl group include a hydroxyl group, a halogen atom, and an alkoxy group.
Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.

  Further, from the viewpoint that the variation in pattern size during observation with a scanning electron microscope (SEM) is small (SEM resistance), a repeating unit in which ALG is a group represented by the following in general formula (A3) is particularly preferable.

R ₂₆ and R ₂₇ each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms.

  Hereinafter, specific examples of the monomer and the repeating unit corresponding to the repeating unit represented by the general formula (A3) are shown.

  Other acrylic esters are preferably alkyl acrylates having 1 to 10 carbon atoms in the alkyl group, for example, methyl acrylate, ethyl acrylate, propyl acrylate, amyl acrylate, cyclohexyl acrylate, acrylic acid Ethylhexyl, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate, 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, benzyl Examples include acrylate, methoxybenzyl acrylate, furfuryl acrylate, and tetrahydrofurfuryl acrylate.

  The other methacrylic acid esters are preferably metalalkyl acrylates having 1 to 10 carbon atoms in the metalalkyl group, such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, amyl methacrylate, cyclohexyl methacrylate, methacrylic acid. Ethyl hexyl, octyl methacrylate, tert-octyl methacrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate, 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, Examples include benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, and tetrahydrofurfuryl acrylate.

In the resin (A), the content of the repeating unit (A1) represented by the general formula (A-1) is preferably from 5 to 60 mol%, more preferably from 10 to 55 mol%, in all repeating units. Preferably it is 15-50 mol%.
As for the content rate of the repeating unit (A2) represented by general formula (A-2), 20-70 mol% is preferable in all the repeating units, More preferably, it is 24-60 mol%, More preferably, it is 28-60 mol% %.
The content of the repeating unit (A3) represented by the general formula (A-3) is preferably 20 to 70 mol%, more preferably 24 to 65 mol%, still more preferably 28 to 60 mol in all repeating units. %.
In the resin (A), the copolymerization ratio of the repeating units (A1), (A2) and (A3) is mol%, and (A1) / (A2) / (A3) = 30-50 / 10-30 / 30. More preferably, it is -50.
The fluorine content of the resin (A) is preferably 0.001 mol / g to 0.03 mol / g. More preferably, it is 0.003 mol / g-0.02 mol / g, More preferably, it is 0.005 mol / g-0.015 mol / g.

As for the content rate of the repeating unit which has an acid-decomposable group, 20-70 mol% is preferable in all the repeating units, More preferably, it is 24-65 mol%, More preferably, it is 28-60 mol%.
The total amount of the repeating units (A1), (A2) and (A3) is generally 60 to 100 mol%, preferably 70 to 100, more preferably 80 to 100 in all repeating units.

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

  The resin used in the present invention 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 usually 20% by mass or more, preferably 30% by mass or more, and more preferably 40% by mass or more. The reaction temperature is usually from 10 ° C to 150 ° C, preferably from 30 ° C to 120 ° C, more preferably from 50 to 100 ° C.

  The weight average molecular weight of the resin according to the present invention is preferably 3,000 to 100,000, more preferably 4,000 to 50,000, and still more preferably 5,000 to 30,0000 in terms of polystyrene by GPC method. 000. A weight average molecular weight of 3,000 or more is preferable from the viewpoint of heat resistance and dry etching resistance, and 100,000 or less is preferable from the viewpoint of developability and film forming property.

The resin (A) is preferably an acrylic / methacrylic repeating unit in which all repeating units are contained. By containing the repeating units (A1), (A2), and (A3), a resin having a glass transition point of 110 to 170 ° C. It can also be obtained. A resin having a glass transition point of 110 to 170 ° C., preferably 130 to 160 ° C. is preferable from the viewpoint of reducing the dependency on density and improving the side lobe margin.
The glass transition temperature (Tg) of the resin (A) can be measured by differential scanning calorimeter.

Controlling the glass transition point within the specific range not only introduces a repeating unit having an alicyclic structure as represented by the general formulas (A1) to (A3), but also has a molecular weight and a dispersity (Mw). / Mn) can be achieved.
In that case, the weight average molecular weight of the resin (A) is usually 5000 to 30000, preferably 6000 to 25000, and more preferably 7000 to 20000.
The degree of dispersion of the resin (A) is usually 3.5 or less, preferably 3.0 or less, more preferably 2.5 or less.
It is preferable that the weight average molecular weight is 5000 or more and the dispersity is 3.5 or less in terms of density dependence and sidelobe margin while maintaining Tg.
In order to control the weight average molecular weight and the degree of dispersion, not only the above reaction conditions are selected, but the reaction monomer solution and the radical polymerization initiator solution are dropped into a solvent or the like heated to a constant temperature, or dropped dropwise. A polymerization method is desirable.
Further, by removing the lower molecular weight side of the resin obtained by polymerization by the fractional reprecipitation method, the effect of the present invention can be further enhanced. The fractional reprecipitation method, for example, removes low molecular weight oligomers with high solvent solubility by pouring the resin solution into the poor solvent of the resin or pouring the poor solvent of the resin into the resin solution. Is the method.
Examples of the poor solvent for the resin (A) include hydrocarbon solvents such as n-hexane, n-heptane, and toluene, mixed solvents of hydrocarbon solvents and ester solvents such as ethyl acetate, alcohols such as distilled water, methanol, and ethanol. These may be used alone or as a mixed solvent.
On the other hand, the above-mentioned reaction solvent and the like can be used as a solvent for dissolving the resin.
Here, the low molecular weight oligomer is, for example, one having a weight average molecular weight of 100 or less.

  In the positive resist composition of the present invention, the blending amount of all the resins according to the present invention in the entire composition is preferably 40 to 99.99% by mass, more preferably 50 to 99.97, based on the total solid content of the resist. % By mass.

[2] Compound that generates acid upon irradiation with actinic rays or radiation (component B)
The resist composition of the present invention contains a compound (a photoacid generator) that generates an acid upon irradiation with actinic rays or radiation.

As the photoacid generator used in the present invention, it is used as a photoinitiator for photocationic polymerization, a photoinitiator for radical photopolymerization, a photodecolorant for dyes, a photochromic agent, a microresist, or the like. Acid by known light (400-200 nm ultraviolet light, far ultraviolet light, particularly preferably g-line, h-line, i-line, KrF excimer laser beam), ArF excimer laser beam, electron beam, X-ray, molecular beam or ion beam Can be selected and used as appropriate.

Examples of other photoacid generators used in the present invention include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, onium salts such as arsonium salts, organic halogen compounds, organic metals / organics. Examples include halides, photoacid generators having an o-nitrobenzyl-type protecting group, compounds that generate photosulfonic acid by photolysis, such as iminosulfonates, disulfone compounds, diazoketosulfones, diazodisulfone compounds, etc. Can do.
Moreover, the group which generate | occur | produced the acid by these light, or the compound which introduce | transduced the compound into the principal chain or side chain of the polymer can be used.

  Furthermore, VNRPillai, Synthesis, (1), 1 (1980), A. Abad etal, Tetrahedron Lett., (47) 4555 (1971), DHR Bartonetal, J. Chem. Soc., (C), 329 (1970), Compounds that generate an acid by light as described in US Pat. No. 3,779,778, European Patent 126,712, and the like can also be used.

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

In the general formula (Z1), R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
X ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of X ^{− in} formula (I).

The carbon number of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is generally 1-30, preferably 1-20.
Two of R _{201 to} R ₂₀₃ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group.
The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).
Specific examples of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include corresponding groups in the compounds (Z1-1), (Z1-2) and (Z1-3) described later.

In addition, the compound which has two or more structures represented by general formula (Z1) may be sufficient. For example, the general formula at least one of R ₂₀₁ to R ₂₀₃ of a compound represented by (Z1) is at least one bond with structure of R ₂₀₁ to R ₂₀₃ of another compound represented by formula (Z1) It may be a compound.

  As more preferred (Z1) component, compounds (Z1-1), (Z1-2), and (Z1-3) described below can be exemplified.

Compound (Z1-1) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (Z1), arylsulfonium compound, i.e., a compound having arylsulfonium as a cation.
Arylsulfonium compound, all of R ₂₀₁ to R ₂₀₃ may be an aryl group or a part of R ₂₀₁ to R ₂₀₃ may be an aryl group with the remaining being an alkyl group.
Examples of the arylsulfonium compound include a triarylsulfonium compound, a diarylalkylsulfonium compound, and an aryldialkylsulfonium compound.
The aryl group of the arylsulfonium compound is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.
The alkyl group that the arylsulfonium compound has as necessary is preferably a linear, branched or cyclic alkyl group having 1 to 15 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, sec. -Butyl group, t-butyl group, cyclopropyl group, cyclobutyl group, cyclohexyl group and the like can be mentioned.
Aryl group R ₂₀₁ to R _203, an alkyl group, an alkyl group (for example, 1 to 15 carbon atoms), an aryl group (e.g., carbon number 6 to 14), an alkoxy group (for example, 1 to 15 carbon atoms), a halogen atom, You may have a hydroxyl group and a phenylthio group as a substituent. Preferred substituents are linear, branched or cyclic alkyl groups having 1 to 12 carbon atoms, linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, most preferably alkyl groups having 1 to 4 carbon atoms, It is a C1-C4 alkoxy group. The substituent may be substituted with any one of the three R _{201 to} R ₂₀₃ , or may be substituted with all three. When R _{201 to} R ₂₀₃ are an aryl group, the substituent is preferably substituted at the p-position of the aryl group.

Next, the compound (Z1-2) will be described.
Compound (Z1-2) is a compound in the case where R _{201 to} R ₂₀₃ in formula (Z1) each independently represents an organic group not containing an aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.
The organic group having no aromatic ring as R ₂₀₁ to R ₂₀₃ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.
R _{201 to} R ₂₀₃ are each independently preferably an alkyl group, an allyl group, or a vinyl group, more preferably a linear, branched, cyclic 2-oxoalkyl group, an alkoxycarbonylmethyl group, most preferably a linear group, A branched 2-oxoalkyl group.

The alkyl group as R ₂₀₁ to R ₂₀₃ may be linear, branched, or cyclic, preferably a linear or branched alkyl group (e.g., methyl group having 1 to 10 carbon atoms, an ethyl group, a propyl Group, butyl group, pentyl group) and cyclic alkyl groups having 3 to 10 carbon atoms (cyclopentyl group, cyclohexyl group, norbornyl group).
The 2-oxoalkyl group as R _{201 to} R ₂₀₃ may be linear, branched or cyclic, and preferably includes a group having> C═O at the 2-position of the above alkyl group. it can.
The alkoxy group in the alkoxycarbonylmethyl group as R ₂₀₁ to R _203, preferred examples include an alkyl group having 1 to 5 carbon atoms (methyl group, ethyl group, propyl group, butyl group, pentyl group).
R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.
Two members out of R _{201 to} R ₂₀₃ may combine to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).

  The compound (Z1-3) is a compound represented by the following general formula (Z1-3), and is a compound having a phenacylsulfonium salt structure.

R _{1c to} R _5c each independently represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom.
R _6c and R _7c represent a hydrogen atom.
Rx and Ry each independently represents an alkyl group, an allyl group, or a vinyl group.
Any two or more of R _{1c to} R _5c and Rx and Ry may be bonded to each other to form a ring structure, and this ring structure includes an oxygen atom, a sulfur atom, an ester bond, and an amide bond. You may go out.
Zc ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of X ^{− in} formula (I).

The alkyl group as R _{1c to} R _{5c may} be linear, branched or cyclic, for example, an alkyl group having 1 to 10 carbon atoms, preferably a linear or branched alkyl group having 1 to 5 carbon atoms. (For example, a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched butyl group, a linear or branched pentyl group), a C3-C8 cyclic alkyl group (for example, a cyclopentyl group, a cyclohexyl group). Can be mentioned.
The alkoxy group as R _{1c to} R _{5c may} be linear, branched or cyclic, for example, an alkoxy group having 1 to 10 carbon atoms, preferably a linear or branched alkoxy group having 1 to 5 carbon atoms. (For example, methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group), C3-C8 cyclic alkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group) ).
Preferably either a straight chain of R _1c to R _5c, branched, cyclic alkyl group, or a linear, branched or cyclic alkoxy group, more preferably the sum of the carbon atoms of R _5c from R _1c 2 to 15 It is. Thereby, solvent solubility improves more and generation | occurrence | production of a particle is suppressed at the time of a preservation | save.

The alkyl group as Rx and Ry may be the same as those of the alkyl group as R _1c to R _5c.
Examples of the 2-oxoalkyl group include a group having> C═O at the 2-position of the alkyl group as R _{1c to} R _5c .
Examples of the alkoxy group in the alkoxycarbonylmethyl group include the same alkoxy groups as R _{1c to} R _5c .
Examples of the group formed by combining Rx and Ry include a butylene group and a pentylene group.

In formula (ZII), (ZIII), R 204 ~R 207 each independently represents an alkyl group which may have an optionally substituted aryl group or a substituent.
Phenyl group and a naphthyl group are preferred as the aryl group of R ₂₀₄ to R _207, more preferably a phenyl group.
The alkyl group as R _{204 to} R ₂₀₇ may be linear, branched or cyclic, and is preferably a linear or branched alkyl group having 1 to 10 carbon atoms (for example, methyl group, ethyl group, propyl group). Group, butyl group, pentyl group) and cyclic alkyl groups having 3 to 10 carbon atoms (cyclopentyl group, cyclohexyl group, norbornyl group).
The R ₂₀₄ to R ₂₀₇ are substituents which may have, for example, an alkyl group (for example, 1 to 15 carbon atoms), an aryl group (e.g. having 6 to 15 carbon atoms), an alkoxy group (for example, 1 to 15 carbon atoms ), Halogen atoms, hydroxyl groups, phenylthio groups, and the like.
X ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of X ^{− in} formula (I).

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

  Hereinafter, other compounds that can be used as the acid generator (component B) of the present invention will be described.

(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.
R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ each independently represents a substituted or unsubstituted alkyl group or aryl group.

Z ⁻ represents a counter anion, for example, a perfluoroalkanesulfonic acid anion such as BF ₄ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , SiF ₆ ²⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , penta Examples include, but are not limited to, condensed polynuclear aromatic sulfonate anions such as fluorobenzene sulfonate 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.

In the above, Ph represents a phenyl group.
The onium salts represented by the general formulas (PAG3) and (PAG4) are known, such as US Pat. Nos. 2,807,648 and 4,247,473, and JP-A-53-101,331. It can be synthesized by the method described in 1.

The addition amount of these photo-acid generators is normally used in the range of 0.001 to 30% by mass, preferably 0.3 to 20% by mass, more preferably 0.8%, based on the solid content in the composition. It is used in the range of 5 to 10% by mass.
Setting the amount of the photoacid generator to be in the above range is preferable from the viewpoint of the balance between the sensitivity, the profile due to light absorption of the resist, and the process (especially baking) margin.
In the present invention, a compound that decomposes upon irradiation with actinic rays or radiation to generate sulfonic acid is preferable.

[3] Other additives In the positive resist composition of the present invention, a surfactant, an organic basic compound, an acid-decomposable dissolution inhibiting compound, a dye, a plasticizer, a photosensitizer, and A compound or the like that promotes solubility in a developer can be contained.

(A) Surfactant The positive resist composition of the present invention contains a surfactant, preferably a fluorine-based and / or silicon-based surfactant.
The positive resist composition of the present invention preferably contains one or two or more of a fluorine-based surfactant, a silicon-based surfactant and a surfactant containing both fluorine atoms and silicon atoms.
When the positive resist composition of the present invention contains the acid-decomposable resin and the surfactant, it is particularly effective when the line width of the pattern is narrower and development defects are further improved.

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 linked body) or a poly (block linked body of oxyethylene and oxypropylene) group, 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 surfactant used is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, and particularly preferably 0.01 to the total amount of the positive resist composition (excluding the solvent). It is mass%-1 mass%.

  Specific examples of surfactants that can be used other than the above include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether. , Polyoxyethylene alkyl allyl ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan Sorbitan fatty acid esters such as monooleate, sorbitan trioleate, sorbitan tristearate, polyoxyethylene sorbitan Nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as laurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tristearate Etc.

(B) Organic basic compound The positive resist composition of the present invention preferably contains an organic basic compound. A preferable organic basic compound is a compound having a stronger basicity than phenol. Of these, nitrogen-containing basic compounds are preferable, and examples thereof include structures represented by the following (A) to (E).

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 1 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 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 ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R ²⁵⁶ 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 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, alkyl group, alkoxy group, acyl group, acyloxy group, aryl group, aryloxy group, nitro group, hydroxyl group and cyano group.

  Preferable specific examples of the nitrogen-containing basic compound include guanidine, 1,1-dimethylguanidine, 1,1,3,3-tetramethylguanidine, 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- Minopiperidine, 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- (2-aminoethyl) morpholine, 1,5-diazabicyclo [ 4.3.0] non-5-ene, 1,8-diazabicyclo [5.4.0] undec-7-ene, 1,4-diazabicyclo [2.2.2] octane, 2,4,5- Triphenylimidazole, N-methylmorpholine, N-ethylmorpholine, N-hydroxyethylmorpholine, N-benzylmorpholine, cyclohexane Examples thereof include tertiary morpholine derivatives such as silmorpholinoethylthiourea (CHMETU), hindered amines described in JP-A-11-52575 (for example, those described in the publication [0005]), and the like. Absent.

Particularly preferred examples are 1,5-diazabicyclo [4.3.0] non-5-ene, 1,8-diazabicyclo [5.4.0] undec-7-ene, 1,4-diazabicyclo [2. 2.2] Octane, 4-dimethylaminopyridine, hexamethylenetetramine, 4,4-dimethylimidazoline, pyrroles, pyrazoles, imidazoles, pyridazines, pyrimidines, tertiary morpholines such as CHMETU, bis (1, 2,2,6,6-pentamethyl-4-piperidyl) sebagate and other hindered amines, N, N-dihydroxyethylaniline, N, N-dibutylaniline, trioctylamine, triphenylimidazole, antipyrine, 2,6-diisopropyl And aniline.
Among them, 1,5-diazabicyclo [4.3.0] non-5-ene, 1,8-diazabicyclo [5.4.0] undec-7-ene, 1,4-diazabicyclo [2.2.2] Octane, 4-dimethylaminopyridine, hexamethylenetetramine, CHMETU, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebagate, N, N-dihydroxyethylaniline, N, N-dibutylaniline, tri Octylamine, triphenylimidazole, antipyrine, and 2,6-diisopropylaniline are preferred.

  These nitrogen-containing basic compounds are used alone or in combination of two or more. The usage-amount of a nitrogen-containing basic compound is 0.001-10 mass% normally with respect to solid content of the whole composition of the resist composition of this invention, Preferably it is 0.01-5 mass%. The above range is preferable from the viewpoint of the balance between the effect and sensitivity of the addition of the nitrogen-containing basic compound and the developability of the non-exposed area.

[4] Solvent (component C)
The positive resist composition of the present invention is dissolved in a solvent that dissolves each of the above components and coated on a support. Solvents used here include ethylene dichloride, cyclohexanone, cyclopentanone, 2-heptanone, γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl ether acetate , Propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), ethylene carbonate, toluene, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, pyruvin Ethyl acetate, propyl pyruvate, N, N-dimethylformamide, dimethyl sulfoxide, N-methyl Pyrrolidone, tetrahydrofuran and the like are preferable to use these solvents singly or in combination.

  Among these, preferable solvents include propylene glycol monomethyl ether acetate, 2-heptanone, γ-butyrolactone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether , Ethylene carbonate, butyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, N-methylpyrrolidone and tetrahydrofuran.

  The resist composition prepared by dissolving each component in a solvent is preferably 3 to 25% by mass, more preferably 5 to 22% by mass, and 7 to 20% by mass as the total solid concentration. % Is more preferable.

  Such a positive resist composition of the present invention is applied onto a substrate to form a thin film. The thickness of this coating film is preferably 0.2 to 1.2 μm. Examples of the substrate that can be used include a normal BareSi substrate, an SOG substrate, and a substrate having an inorganic antireflection film described below. If necessary, a commercially available inorganic or organic antireflection film can be used.

As the antireflection film, an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, α-silicon, and an organic film type made of a light absorber and a polymer material can be used. The former requires equipment such as a vacuum deposition apparatus, a CVD apparatus, and a sputtering apparatus for film formation. Examples of the organic antireflection film include a condensate of a diphenylamine derivative and a formaldehyde-modified melamine resin described in JP-B-7-69611, an alkali-soluble resin, a light absorber, and maleic anhydride copolymer described in US Pat. No. 5,294,680. A reaction product of a coalescence and a diamine type light absorbing agent, a resin binder described in JP-A-6-186863 and a methylolmelamine thermal crosslinking agent, a carboxylic acid group, an epoxy group and a light-absorbing group described in JP-A-6-118656. An acrylic resin-type antireflection film in the same molecule, a composition comprising methylol melamine and a benzophenone-based light absorber described in JP-A-8-87115, and a low-molecular light absorber added to a polyvinyl alcohol resin described in JP-A-8-179509 And the like.
Further, as the organic antireflection film, DUV30 series, DUV-40 series, ARC25, AC-2, AC-3, AR19, AR20, etc., manufactured by Brewer Science can be used.

Appropriate use of the resist solution on a substrate (eg, silicon / silicon dioxide coating) used for the manufacture of precision integrated circuit elements (on a substrate provided with the antireflection film if necessary), spinner, coater, etc. A good resist pattern can be obtained by applying through a predetermined coating method, exposing through a predetermined mask, baking and developing. Here, the exposure light is preferably light having a wavelength of 150 nm to 250 nm. Specific examples include a KrF excimer laser (248 nm), an ArF excimer laser (193 nm), an F ₂ excimer laser (157 nm), an X-ray, and an electron beam.

  Examples of the developer 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, diethylamine, and di-n. -Secondary amines such as butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide. An alkaline aqueous solution (usually 0.1 to 10% by mass) of cyclic amines such as pyrrole and pihelidine can be used. Furthermore, an appropriate amount of alcohol or surfactant may be added to the alkaline aqueous solution.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.

Synthesis Example Synthesis of Resin (1) 2-Adamantyl-2-methyl methacrylate, dihydroxyadamantane trifluoromethyl acrylate and norbornane lactone methacrylate were charged at a ratio of 40/20/40, and propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether = 60. / 40 was dissolved to prepare 450 g of a solution having a solid content concentration of 22%. 1 mol% of Wako Pure Chemical V-601 was added to this solution as a polymerization initiator, and this was heated to 80 ° C. over 6 hours in a nitrogen atmosphere, and a mixture of propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether = 60/40 It was dripped at 50g of solutions. After completion of dropping, the reaction solution was stirred for 2 hours. After completion of the reaction, the reaction solution was cooled to room temperature, crystallized in 5 L of a mixed solvent of hexane / ethyl acetate = 9/1, and the precipitated white powder was collected by filtration to recover the target resin (1).
^The polymer composition ratio determined from ¹³ CNMR was 44/16/40. Moreover, the standard polystyrene conversion weight average molecular weight calculated | required by GPC measurement was 8700, and dispersion degree was 2.1. Moreover, as a result of measuring about an oligomer component, 9% of oligomers with a molecular weight of 100 or less were contained.

  Resin (2) to (8) and comparative resins (1) and (2) were prepared in the same manner by changing the type and amount of the monomer. The monomer composition, molecular weight, dispersity (Mw / Mn), and content of oligomer components having a molecular weight of 100 or less are described below.

Examples 1 to 8 and Comparative Examples 1 and 2
(Preparation and evaluation of positive resist composition)
Resin synthesized in the above synthesis example (2 g),
Photoacid generator (blending amount shown in Table 2),
Organic basic compound (4 mg),
Surfactant (10mg) if necessary
And dissolved in the solvent shown in Table 1 so as to have a solid content of 11% by mass, followed by filtration with a 0.1 μm microfilter, and positive resist compositions of Examples 1 to 8 and Comparative Examples 1 and 2 Was prepared. In addition, the ratio at the time of using two or more about each component in Table 1 is a mass ratio.

(Evaluation test)
First, ARC-29A-8 manufactured by Brewer Science Co., Ltd. was applied as an antireflection film to a silicon wafer at a thickness of 78 nm using a spin coater, dried, and then the resulting positive photoresist composition was applied thereon. The film was dried at 90 ° C. for 90 seconds to prepare a positive photoresist film having a thickness of about 0.3 μm, and exposed to an ArF excimer laser (ArF stepper manufactured by ISI having a wavelength of 193 nm and NA = 0.6). The heat treatment after the exposure was performed at 115 ° C. for 90 seconds, developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution, and rinsed with distilled water to obtain a resist pattern profile.

[LER (Line Edge Roughness)]:
Using a length-measuring scanning electron microscope (SEM), measurement was performed on a pattern of line / space = 1: 0.9 (line width 150 nm). In the measurement monitor, line pattern edges were detected at a plurality of positions, and the dispersion (3σ) of variations in the detected positions was used as an index of edge roughness (unit: nm). The smaller the value, the better the edge roughness.

[Pattern collapse]
Using a length-measuring scanning electron microscope (SEM), pattern fall of a line / space pattern (line / space = 1: 1) having a line width of 130 nm is observed, the optimum exposure amount is Eo, and pattern fall is observed. The exposure amount was Elimit, and the value obtained by the following equation was used as an index of pattern collapse. The higher this value, the better the pattern collapse property.
Pattern collapseability (%) = (Elimit−Eo) / Eo × 100
These evaluation results are shown in Table 1 below.

The symbol of each component in Table 1 shows the following.
[Basic compounds]
N1: N, N-dihydroxyethylaniline N2: N, N-dibutylaniline N3: trioctylamine N4: triphenylimidazole N5: antipyrine N6: 2,6-diisopropylaniline

[Surfactant]
W1: Megafuck F176 (Dainippon Ink Chemical Co., Ltd.) (Fluorine)
W2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.)
(Fluorine and silicone)
W3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.)
W4: Polyoxyethylene nonylphenyl ether W5: Troisol S-366 (manufactured by Troy Chemical Co., Ltd.)

〔solvent〕
S1: Propylene glycol monomethyl ether acetate S2: Propylene glycol monomethyl ether S3: γ-butyrolactone S4: Cyclohexanone S5: Ethyl lactate S6: Butyl acetate

  From the results in Table 2, it can be seen that the composition of the present invention can suppress pattern collapse and LER (line edge roughness).

Claims (2)

The repeating unit (A1) represented by the following formula (A-1), the repeating unit (A2) represented by the following formula (A-2), and the repeating unit (A3) represented by the following formula (A-3) ), A resin (A) whose dissolution rate in an alkaline developer is increased by the action of an acid, a compound (B) that generates an acid upon irradiation with actinic rays or radiation, and a solvent (C) Positive resist composition.

In general formulas (A-1), (A-2) and (A-3),
R _{1a to} R _3a each independently represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group. However, at least one of R _{1a to} R _{3a represents} a fluorine atom or an alkyl group substituted with at least one fluorine atom.
Ring A represents a cyclic lactone structure.
p represents an integer of 1 to 4.
G represents a fluorine atom, a chlorine atom, a hydroxyl group, a cyano group, an alkyl group or an alkoxy group.
ALG represents an acid-decomposable group. A pattern forming method comprising: forming a resist film on a semiconductor substrate with the resist composition according to claim 1; and exposing and developing the resist film.