JP2006011250A - Resist composition and pattern forming method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resist composition having small coating ratio dependence with high sensitivity for far ultraviolet-ray exposure, in particular, for ArF excimer laser exposure by being suitable in ultra-microscopic lithographic process, such as manufacture of ultra-LSIs and high capacity microchips and other photofabrication processes, and to provide a pattern formation method using it. <P>SOLUTION: The resist composition contains (A) a resin that dissolves by action of an acid having a repeating unit having hydroxy adamantane, and in which the dissolving speed to an alkali developer increases, (B) an oxime sulfonate compound that generates an acid by irradiation with an active beam or radiation, and (C) at least one of propylene glycol monomethyl ether carboxyrate and lactic acid alkyl, and a mixture solvent containing a cyclic keton solvent. The pattern forming method uses this resist composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resist composition for microfabrication such as a semiconductor element that is sensitive to far ultraviolet rays and a pattern forming method using the same, and more particularly to a resist composition for far 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.

The chemical amplification resist is suitable as a photoresist for irradiation with ultraviolet rays or far ultraviolet rays, but among them, it is necessary to cope with the required characteristics in use. For example, when using 248 nm light of a KrF excimer laser, a resist composition using a polymer in which an acetal group or a ketal group is introduced as a protective group to a hydroxystyrene-based polymer that has little light absorption is proposed. Has been.
These are suitable when using 248 nm light of a KrF excimer laser, but when using an ArF excimer laser as a light source, the intrinsic sensitivity is still too high and the sensitivity is low. In addition, there are other drawbacks associated therewith, such as degradation of resolution, degradation of focus tolerance, degradation of pattern profile, and the like, and many improvements are still required.

  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. As such a resin, a monomer having a carboxylic acid site such as acrylic acid or methacrylic acid or a monomer having a hydroxyl group or a cyano group in the molecule is copolymerized with a monomer having an alicyclic hydrocarbon group. Resin.

  Patent Document 1 (Japanese Patent Laid-Open No. 9-73173) discloses a resist composition having high resolution, high sensitivity, and excellent dry etching resistance, and a pattern that reduces the occurrence of cracks and pattern peeling during development of the resist pattern. For the purpose of the formation method, the use of a resin containing an alkali-soluble group protected by an alicyclic hydrocarbon group to which a lower alkyl group is bonded is disclosed.

  Patent Document 2 (Japanese Patent Laid-Open No. 11-109632) discloses a polar group-containing fat such as a hydroxyadamantyl group as a radiation-sensitive material having transparency, high sensitivity, adhesion to a substrate, and etching resistance with respect to far ultraviolet rays. A material containing a resin having a cyclic functional group and a functional group that generates an alkali-soluble group with an acid is described.

  Patent Document 3 (Japanese Patent Laid-Open No. 2000-338874) describes a resist composition containing a resin containing a repeating unit having a hydroxyadamantane structure in the side chain and a repeating unit having an acid-decomposable group having an alicyclic structure. is doing.

Patent Document 4 (Japanese Patent Application Laid-Open No. 8-259626) discloses a resist composition having high transparency to ArF excimer light, resistance to dry etching, sensitivity, and resolution, via a bridged cyclic hydrocarbon in the side chain. Describes a resist composition containing a resin containing a repeating unit having a carboxyl group protected by a carboxyl group or an acid-decomposable group at the terminal.
Patent Document 5 (Japanese Patent Laid-Open No. 2000-314956) describes a chemically amplified resist containing a specific oxime derivative and a polystyrene resin. Patent Document 6 (Japanese Patent Application Laid-Open No. 2002-303979) also describes a chemically amplified resist containing an oxime derivative.

  As various resist compositions are studied in this way, a resist composition having high sensitivity and small coverage dependency is desired for ArF excimer laser exposure. Coverage dependency means that the resist performance varies depending on the mask coverage.

JP-A-9-73173 JP-A-11-109632 JP 2000-338664 A JP-A-8-259626 JP 2000-314956 A JP 2002-303979 A

  Therefore, the object of the present invention can be suitably used in ultra-microlithography processes such as the manufacture of VLSI and high-capacity microchips and other photofabrication processes, and for deep ultraviolet exposure, particularly ArF excimer lasers. Provided are a resist composition having high sensitivity and low coverage dependency for exposure and a pattern forming method using the same.

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

   (1) (A) a resin having a repeating unit represented by the general formula (I), which decomposes by the action of an acid and increases the dissolution rate in an alkali developer, and (B) by irradiation with actinic rays or radiation A resist composition comprising a compound represented by the following general formula (1) that generates an acid, and (C) a mixed solvent containing at least one of propylene glycol monomethyl ether carboxylate and alkyl lactate and a cyclic ketone solvent.

In general formula (I), R ₃₀ represents a hydrogen atom or a methyl group.
R _{31 to} R ₃₃ each independently represents a hydrogen atom, a hydroxyl group or an alkyl group, provided that at least one represents a hydroxyl group.

In general formula (1), R ₁ and R ₂ each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, or a cyano group. R ₁ and R ₂ may combine to form a ring.
R ₃ represents an alkyl group, a cycloalkyl group or an aryl group having a fluorine atom.
R ₁ and R ₂ may be bonded to R ₁ or R ₂ of another compound represented by the general formula (1) through a single bond or a linking group.

  (2) The resist composition as described in (1) above, further comprising a nitrogen-containing basic compound.

(3) The resist composition as described in (1) or (2) above, further comprising a sulfonium salt compound that generates an acid upon irradiation with actinic rays or radiation.
(4) A pattern forming method comprising: forming a resist film from the resist composition according to any one of (1) to (3) above; and exposing and developing the resist film.

  According to the present invention, it is possible to provide a resist composition that has high sensitivity and is known to have a low coverage dependency.

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 does not have a substituent and what has a substituent. . For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

[1] Resin (A) which decomposes by the action of an acid and increases the dissolution rate in an alkaline developer
The resin (A) used in the present invention contains a repeating unit represented by the following general formula (I) and decomposes by the action of an acid to increase the dissolution rate in an alkaline developer (acid-decomposable resin) It is.

In general formula (I), R ₃₀ represents a hydrogen atom or a methyl group.
R _{31 to} R ₃₃ each independently represent a hydrogen atom, a hydroxyl group or an alkyl group (preferably having 1 to 5 carbon atoms), provided that at least one represents a hydroxyl group.

In the repeating unit represented by the general formula (I), it is more preferable that two of R _{31 to} R ₃₃ are hydroxyl groups.

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

Resin (A) is a resin (acid-decomposable resin) that decomposes by the action of an acid and increases the dissolution rate in an alkali developer, and is a group (acid-decomposable group) that decomposes by the action of an acid and becomes alkali-soluble. However, the acid-decomposable group may be contained in any repeating unit contained in the resin.
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 groups are shown. B ⁰ represents a —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. R ⁰ represents a single bond or a divalent or higher valent aliphatic or aromatic hydrocarbon group, and —Ar— represents a monocyclic or polycyclic divalent or higher valent aromatic group.

  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.

  Examples of the substituent that each group may have include, for example, a hydroxyl group, a halogen atom (fluorine, chlorine, bromine, iodine), a nitro group, a cyano group, the above alkyl group, a methoxy group, and an ethoxy group.・ Hydroxyethoxy group, propoxy group, hydroxypropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, alkoxy group such as t-butoxy group, alkoxycarbonyl group such as methoxycarbonyl group, ethoxycarbonyl group, benzyl group, Aralkyl groups such as phenethyl group and cumyl group, aralkyloxy groups, acyl groups such as formyl group, acetyl group, butyryl group, benzoyl group, cyanamyl group, valeryl group, acyloxy groups such as butyryloxy group, the above alkenyl groups, vinyloxy groups・ Propenyloxy group ・ Allyloxy group ・ Butenyloxy group It alkenyloxy group, said aryl group, an aryloxy group such as phenoxy group, and the like aryloxycarbonyl group such as benzoyloxy group.

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 Examples include 1-alkoxyethyl group such as ethyl group, alkoxymethyl group such as 1-methoxymethyl group and 1-ethoxymethyl group, tetrahydropyranyl group, tetrahydrofuranyl group, trialkylsilyl group, 3-oxocyclohexyl group and the like. Can do. X ₁ represents an oxygen atom or a sulfur atom, preferably an oxygen atom.

  As the repeating unit having an acid-decomposable group, a repeating unit represented by the following general formula (II) is preferable.

In the general formula (II), R ₁ represents a hydrogen atom or a methyl group, A represents a single bond or a linking group, and ALG represents a group represented by the following general formulas (pI) to (pVI).

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 ₁₆ each independently represents a linear or branched alkyl group or alicyclic hydrocarbon group having 1 to 4 carbon atoms, provided that at least one of R _{12 to} R ₁₄ , or Either R ₁₅ or R ₁₆ represents an alicyclic hydrocarbon group.
R _{17 to} R ₂₁ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or an alicyclic hydrocarbon group, provided that at least one of R _{17 to} R ₂₁ Represents an alicyclic hydrocarbon group. Further, either R ₁₉ or R ₂₁ represents a linear or branched alkyl group or alicyclic hydrocarbon group having 1 to 4 carbon atoms.
R _{22 to} R ₂₅ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or an alicyclic hydrocarbon group, provided that at least one of R _{22 to} R ₂₅ Represents an alicyclic hydrocarbon group. R ₂₃ and R ₂₄ may be bonded to each other to form a ring.

In the general formulas (pI) to (pVI), the alkyl group in R _{12 to} R ₂₅ represents a linear or branched alkyl group having 1 to 4 carbon atoms. 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.
In addition, examples of the substituent that the alkyl group may have include an alkoxy group having 1 to 4 carbon atoms, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom), an acyl group, an acyloxy group, and a cyano group. Group, hydroxyl group, carboxy group, alkoxycarbonyl group, nitro group and the like.

The alicyclic hydrocarbon group in R _{11 to} R _{25 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.

  In the present invention, preferred examples of the alicyclic moiety 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 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, and a cyclododecanyl group.

  Examples of the substituent that these alicyclic hydrocarbon groups may have include an 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. To express. 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 substituent that the alkyl group and the alkoxy group may have include a hydroxyl group, a halogen atom, and an alkoxy group (preferably having 1 to 4 carbon atoms).

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

  In the present invention, it is particularly preferable that the resin (A) has an alkali-soluble group protected by a 2-alkyl-2-adamantyl group or a 1-adamantyl-1-alkyl group.

Moreover, it is preferable that resin (A) contains the repeating unit which has an alicyclic lactone structure from the point which prevents pattern collapse.
Examples of the repeating unit having an alicyclic lactone structure include a repeating unit having cyclohexanelactone, norbornanelactone, or adamantanelactone. Among these, a repeating unit having norbornane lactone or adamantane lactone is preferable, and a repeating unit having norbornane lactone is more preferable.

  For example, as a repeating unit having cyclohexanelactone, a repeating unit having groups represented by the following general formulas (V-1) and (V-2), and a repeating unit having norbornanelactone as the repeating unit (V-3) ) And the repeating unit having a group represented by (V-4) and the repeating unit having an adamantane lactone may include a repeating unit having a group represented by the following general formula (V).

In General Formulas (V-1) to (V-4), R _{1b to} R _5b each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, or an alkenyl group. Two of R _{1b to} R _5b may combine to form a ring.

In the general formulas (V-1) to (V-4), the alkyl group in R _{1b to} R _5b is preferably a linear or branched alkyl group having 1 to 12 carbon atoms, more preferably 1 carbon atom. -10 linear or branched alkyl groups, 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.

As a cycloalkyl group in R _<1b > -R < _5b >, C3-C8 things, such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, are preferable.
As an alkenyl group in R _<1b > -R < _5b >, C2-C6 things, such as a vinyl group, a propenyl group, a butenyl group, a hexenyl group, are preferable.
Examples of the ring formed by combining two of R _{1b to} R _5b include 3- to 8-membered rings such as a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, and a cyclooctane ring.
In the general formulas (V-1) to (V-4), R _{1b to} R _5b 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 (V-1) to (V-4) include a repeating unit represented by the following general formula (V).

In general formula (V), _Rb0 represents a hydrogen atom, a halogen atom, or an alkyl group.
The alkyl group as R _b0 may have a substituent, and as a preferable substituent, the alkyl group as R _1b in the general formulas (V-1) to (V-4) has Examples of preferable substituents include those exemplified above.
Examples of the halogen atom for R _b0 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R _b0 is preferably a hydrogen atom.
A ′ represents a single bond, an ether group, an ester group, a carbonyl group, an alkylene group, or a divalent group obtained by combining these.
B ₂ represents a group represented by any one of the general formulas (V-1) to (V-4). In A ′, 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 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 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 substituent that the alkyl group and the alkoxy group may have include a hydroxyl group, a halogen atom, and an alkoxy group having 1 to 4 carbon atoms.
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 the general formula (V) are shown below, but the contents of the present invention are not limited to these.

  Examples of the repeating unit having adamantane lactone include the repeating unit represented by the following general formula (VI).

In the general formula (VI), A ₆ represents a single bond, an alkylene group, a cycloalkylene group, an ether group, a thioether group, a carbonyl group, or a group of two or more groups selected from the group consisting of ester groups.
R _6a represents a hydrogen atom, an alkyl group (preferably having 1 to 4 carbon atoms), a cyano group, or a halogen atom.

In the general formula (VI), examples of the alkylene group represented by A ₆ 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 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 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 substituent that the alkyl group and the alkoxy group may have include a hydroxyl group, a halogen atom, and an alkoxy group (preferably having 1 to 4 carbon atoms). 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.

In the general formula (VI), the A ₆ cycloalkylene group preferably has 3 to 10 carbon atoms, and examples thereof include a cyclopentylene group, a cyclohexylene group, and a cyclooctylene group.

Examples of the substituent that the bridged alicyclic ring containing Z ₆ may have include, for example, a halogen atom, an alkoxy group (preferably having 1 to 4 carbon atoms), and an alkoxycarbonyl group (preferably having 1 to 1 carbon atom). 5), acyl group (for example, formyl group, benzoyl group), acyloxy group (for example, propylcarbonyloxy group, benzoyloxy group), alkyl group (preferably having 1 to 4 carbon atoms), carboxyl group, hydroxyl group, alkylsulfonylsulfur A famoyl 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 the general formula (VI), the oxygen atom of the ester group bonded to A ₆ may be bonded at any position of the carbon atom constituting the bridged alicyclic ring structure containing Z ₆ .

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

  The resin (A) preferably further contains a repeating unit having a lactone structure represented by the following general formula (IV).

In general formula (IV), R _1a represents a hydrogen atom or a methyl group.
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 represent 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 a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group. 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 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 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 substituent that the alkyl group and the alkoxy group may have include a hydroxyl group, a halogen atom, and an alkoxy group (preferably having 1 to 4 carbon atoms). 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.

  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.

  As the repeating unit represented by the general formula (IV), the following repeating units are preferable from the viewpoint of exposure margin.

  In addition to the above repeating units, the resin is various for the purpose of adjusting dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general required characteristics of resist, such as resolution, heat resistance, and sensitivity. Repeating units.

Examples of such a repeating unit include, but are not limited to, repeating structural units corresponding to the following monomers.
As a result, the performance required for the resin, especially
(1) Solubility in coating solvent,
(2) Film formability (glass transition point),
(3) Alkali developability,
(4) Membrane slip (hydrophobic, alkali-soluble group selection),
(5) Adhesion of unexposed part to substrate,
(6) Dry etching resistance,
Etc. can be finely adjusted.
As such a monomer, for example, it has one addition polymerizable unsaturated bond selected from acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. A compound etc. can be mentioned.

  In the resin, the molar ratio of each repeating unit adjusts resist dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general resist performance such as resolution, heat resistance, and sensitivity. Therefore, it is set appropriately.

In the resin (A), the content of the repeating unit represented by the general formula (I) is preferably 5 to 45 mol%, more preferably 10 to 40 mol%, still more preferably 15 to 35 in all repeating units. Mol%.
In the resin (A), the content of the repeating unit having an acid-decomposable group is preferably 20 to 70 mol%, more preferably 24 to 65 mol%, still more preferably 28 to 60 mol% in all repeating units. is there.
In the resin (A), the content of the repeating unit represented by the general formula (II) is preferably 24 to 55 mol%, more preferably 26 to 50 mol%, still more preferably 28 to 45 in all repeating units. Mol%.

In the resin (A), the content of the repeating unit having an alicyclic lactone structure is preferably 5 to 60 mol%, more preferably 10 to 55 mol%, still more preferably 15 to 50 mol% in all repeating units. .
In the resin (A), the content of the repeating unit having a lactone structure in the side chain represented by the general formula (V) is preferably 5 to 60 mol%, more preferably 10 to 50 mol% in all repeating units. More preferably, it is 15-45 mol%.
In the resin (A), the content of the repeating unit having a lactone structure in the side chain represented by the general formula (VI) is preferably 5 to 60 mol%, more preferably 10 to 50 mol% in all repeating units. More preferably, it is 15-45 mol%.
In the resin (A), the content of the repeating unit having a lactone structure in the side chain represented by the general formula (IV) is preferably 5 to 60 mol%, more preferably 10 to 50 mol% in all repeating units. More preferably, it is 15-45 mol%.
When the composition of the present invention is for ArF exposure, the resin preferably does not have an aromatic group from the viewpoint of transparency to ArF light.

The resin used in the present invention can be synthesized by radical polymerization according to a conventional method. In addition, as a method of synthesizing a resin having a low degree of dispersion, a living radical polymerization method or the like can be exemplified.
As a general synthesis method, monomer species are charged into a reaction vessel in a batch or in the course of reaction, and dissolved in a solvent capable of dissolving various monomers as necessary, and then uniform, and then an inert gas atmosphere such as nitrogen or argon Under the heating, polymerization is started using a commercially available radical initiator (azo initiator, peroxide, etc.) as necessary. 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.

  In the polymerization, preferred solvents include, for example, amide solvents such as N, N-dimethylacetamide, glycol ether solvents such as propylene glycol monomethyl ether and diethylene glycol dimethyl ether, alkyl lactate solvents such as ethyl lactate, ketone solvents such as methyl ethyl ketone, tetrahydrofuran and the like. And cyclic ether solvents, lactone solvents such as γ-butyrolactone, carbonate solvents such as propylene carbonate, propylene glycol monomethyl ether monoalkyl ether ester solvents such as propylene glycol monomethyl ether acetate, and nitrile solvents such as acetonitrile and butyronitrile. The solvent species can be used alone or as a mixed solvent.

The reaction temperature is preferably 80 ° C to 170 ° C, more preferably 90 ° C to 150 ° C, still more preferably 100 ° C to 130 ° C. If the reaction temperature is too high, it is not efficient such as decomposition of the monomer and conversely a decrease in reaction conversion. In addition, since the reaction temperature affects the molecular weight, it is preferably managed at the target temperature ± 3 ° C., more preferably at the target temperature ± 1 ° C.
The reaction concentration is 22% by mass or less, preferably 20% by mass or less, and more preferably 15% by mass or less.

As the polymerization method, a drop polymerization method is suitable. The dropping polymerization method is a method in which a reaction solution is divided into an initial tension side (initial tension solution) and a dropping side (dropping solution), and the dropwise solution is added while dropping into the initial tension solution. A method for this is a batch polymerization method in which a reaction solution is first charged into a reaction apparatus and an initiator is added. Among the dropping polymerization methods, it is desirable to add more reactive monomer species to the dropping solution side. Moreover, the method of adding a radical initiator also to the dripping solution side is desirable. Of course, the monomer species and the radical initiator may be separate solutions.
A longer dropping time is preferred. Preferably it is 3 hours or more, preferably 4 hours or more, more preferably 6 hours or more. However, if it is too long, it is not efficient in terms of work.

  Next, narrowing the degree of dispersion in the purification step is a method in which the reaction solution is poured into a poor solvent or a crystallization step in which a poor solvent is added to the reaction solution, a solution in which the reaction solution is replaced with another good solvent, or crystallization. Examples thereof include a method in which a later powder, a solution obtained by dissolving a wet cake in a good solvent is added to a poor solvent, or by fractional reprecipitation in which a poor solvent is added to this solution. Examples of the good solvent include the reaction solvents described above. Examples of the poor solvent include distilled water and hydrocarbon solvents such as methanol, ethanol, isopropanol, hexane, heptane, and toluene.

  The weight average molecular weight of the resin (A) according to the present invention is preferably from 3,000 to 30,000, more preferably from 4500 to 15,000, particularly preferably from 4,000 to 8 as a polystyrene-converted value by the GPC method. , 000. Such a molecular weight range is preferable in terms of improving sensitivity and preventing scum. Further, if the weight average molecular weight is less than 3,000, deterioration of heat resistance and dry etching resistance is observed, which is not preferable.

  Further, the degree of dispersion (Mw / Mn) of the resin according to the present invention is preferably 1.8 or less, more preferably 1.3 to 1.8, and particularly preferably 1.5 to 1.8. Such a range of the degree of dispersion is preferable in terms of density dependence.

  The blending amount of all the resins according to the present invention in the whole composition is preferably 40 to 99.99% by mass, more preferably 50 to 99.97% by mass in the total resist solid content.

  [2] An oxime sulfonate compound that generates an acid upon irradiation with an actinic ray or radiation represented by the general formula (1)

In general formula (1), R ₁ and R ₂ each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, or a cyano group. R ₁ and R ₂ may combine to form a ring. R ₃ represents an alkyl group, a cycloalkyl group or an aryl group having a fluorine atom.
R ₁ and R ₂ may be bonded to R ₁ or R ₂ of another compound represented by the general formula (1) through a single bond or a linking group.

Each group as R ₁ and R ₂ preferably has _{1 to} 16 carbon atoms and may have a substituent.
Each group as R ₃ preferably has 1 to 16 carbon atoms, more preferably 2 to 12 carbon atoms, and may have a substituent.
The alkyl group as R ₁ and R ₂ may be linear or branched, and is preferably an alkyl group having 1 to 16 carbon atoms. As the alkyl group, for example, methyl group, ethyl group, propyl group, i-propyl group, butyl group, i-butyl group, t-butyl group, t-amyl group, n-hexyl group, n-octyl group, i -Alkyl groups such as octyl group, n-decyl group, undecyl group, dodecyl group, hexadecyl group, trifluoromethyl group, perfluoropropyl group, perfluorobutyl group, perfluoro-t-butyl group, perfluorooctyl group, perfluoroundecyl group 1,1-bistrifluoromethylethyl group and the like.
The cycloalkyl group as R ₁ and R ₂ preferably has 3 to 8 carbon atoms, and examples thereof include a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group.

The alkenyl group as R ₁ and R ₂ may be linear, branched or cyclic, and is preferably an alkenyl group having 2 to 16 carbon atoms. Examples of the linear or branched alkenyl group include allyl group, methallyl group, vinyl group, methylallyl group, 1-butenyl group, 3-butenyl group, 2-butenyl group, 1,3-pentadienyl group, and 5-hexenyl group. 2-oxo-3-pentenyl group, decapentaenyl group, 7-octenyl group and the like.
Examples of the cyclic alkenyl group include a cyclobutenyl group, a cyclohexenyl group, a cyclopentadienyl group, a bicyclo [4.2.4] dodeca-3,7-dien-5-yl group, and the like.

The alkynyl group as R ₁ and R ₂ preferably has 2 to 16 carbon atoms, for example, ethynyl group, propargyl group, 2-butynyl group, 4-hexynyl group, 2-octynyl group, phenylethynyl group, cyclohexylethynyl group and the like. Is mentioned.

The aryl group as R ₁ and R ₂ preferably has 5 to 16 carbon atoms, and more preferably has 6 to 14 carbon atoms such as phenyl group, tolyl group, methoxyphenyl group and naphthyl group. It is done.
The heterocyclic group preferably has 5 to 16 carbon atoms, and examples thereof include those in which the ring-constituting atoms of the aryl group are replaced with heteroatoms, such as thiophenefuryl group and thienyl group. .

When R ₁ and R ₂ combine to form a ring, for example, an alkylene group, an alkenylene group, an alkynylene group, —O—, —S—, —N—, —CO—, or a combination of at least two of these Can form a 5- to 10-membered ring.

The alkyl group having a fluorine atom as R ₃ is a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and an alkyl group having 1 to 16 carbon atoms is preferable. .
For example, trifluoromethyl group, perfluoropropyl group, perfluorobutyl group, perfluoro-t-butyl group, perfluorooctyl group, perfluoroundecyl group, 1,
Examples thereof include a 1-bistrifluoromethylethyl group.
The cycloalkyl group having a fluorine atom as R ₃ is a cycloalkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and a cycloalkyl group having 3 to 16 carbon atoms is preferable.

The aryl group having a fluorine atom as R ₃ is an aryl group in which at least one hydrogen atom is substituted with a fluorine atom, and may be an aryl group having a fluorine atom in the substituent.
Preferably, it is an aryl group having 5 to 16 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, and more preferably, a phenyl group, a tolyl group, in which at least one hydrogen atom is substituted with a fluorine atom, Examples thereof include aryl groups having 6 to 14 carbon atoms such as methoxyphenyl group and naphthyl group.

Examples of the substituent that each of the above groups may have include, for example, an alkoxy group (preferably having 1 to 4 carbon atoms, for example, a methoxy group, an ethoxy group, a hydroxyethoxy group, a straight or branched propoxy group, a straight chain or Branched butoxy group), halogen atom (for example, fluorine atom, chlorine atom, iodine atom), cyano group, hydroxy group, carboxy group, nitro group, aryloxy group (preferably having 6 to 14 carbon atoms), alkylthio group (preferably 1 to 4 carbon atoms), an aryl group (similar to the aryl group as R ₁ ), an aralkyl group (preferably 6 to 14 carbon atoms such as a benzyl group or a naphthylmethyl group), or the following general formula (1A) Group etc. which are shown by these, etc. are mentioned.
As for the aryl group and heterocyclic group, examples of the substituent further include an alkyl group (for example, the same as the alkyl group as R ₁ , preferably 1 to 4 carbon atoms).

In the above formula, R ₁ and R ₂ have the same meanings as R ₁ and R ₂ in the general formula (1).

  Specific examples of the compound represented by the general formula (1) are shown below, but the present invention is not limited thereto.

The compound represented by the general formula (1) is, for example, SRSandler & W. Karo, Organic Functional
Group Preparations, Vol. 3, Academic Press), for example, by reacting ketones with hydroxylamine or its salts, or by nitrosating an "active" methylene group with nitrous acid or alkylbinitrate It can be obtained by reacting the oxime compound with the desired acid halide. Reference can also be made to the method described in JP-A No. 2000-314956.

  The addition amount of the compound represented by the general formula (1) is usually 0.1 to 10% by mass, preferably 0.5 to 5% by mass, based on the solid content in the composition.

  In this invention, you may use together the compound (photo-acid generator) which generate | occur | produces an acid by irradiation of other active rays or a radiation with the compound represented by General formula (1).

  As the photoacid generator that may be used in combination, a photoinitiator for photocationic polymerization, a photoinitiator for radical photopolymerization, a photodecolorant for dyes, a photochromic agent, or a well-known photo-acid generator Of 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 A compound that generates an acid upon irradiation with light or radiation and a mixture thereof can be appropriately selected and used.

For example, diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, onium salts such as arsonium salts, organic halogen compounds, organic metal / organic halides, photoacid generators having o-nitrobenzyl type protecting groups Examples thereof include a compound capable of generating a sulfonic acid by photolysis represented by an agent, iminosulfonate, a disulfone compound, a diazoketosulfone, a diazodisulfone compound, and the like.
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), DHRBarton et al, J. Chem. Soc., (C), 329 (1970), US Pat. No. 3,779,778, European Patent 126,712, and the like, compounds that generate an acid by light can also be used.

  In the present invention, as the photoacid generator used in combination with the compound of the general formula (1), a sulfonium salt compound is particularly preferable.

  The amount of the compound represented by the general formula (1) and the other photoacid generator used is usually a molar ratio (as the compound represented by the general formula (1) / other acid generator, usually 90/10 to 10 / 90, preferably 90/10 to 25/75, more preferably 80/20 to 40/60.

  Other photoacid generators will be described more specifically below.

  (1) An iodonium salt represented by the following general formula (PAG1) or a sulfonium salt represented by the general formula (PAG2).

Ar ¹ and Ar ² each independently represents an aryl group.
Examples of the substituent that the aryl group may have include an alkyl group (particularly a haloalkyl group as the substituted alkyl), a cycloalkyl group, an aryl group, an alkoxy group, a nitro group, a carboxyl group, an alkoxycarbonyl group, a hydroxy group, a mercapto group. Group, a halogen atom, and the like.

R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ each independently represents an alkyl group, a cycloalkyl group or an aryl group. Preferred are an aryl group having 6 to 14 carbon atoms, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, and substituted derivatives thereof.
Preferable substituents are an aryl group having 1 to 8 carbon atoms, an alkyl group having 1 to 8 carbon atoms, a nitro group, a carboxyl group, a hydroxy group, and a halogen atom, and an alkyl group and a cycloalkyl group. Is an alkoxy group having 1 to 8 carbon atoms, a carboxyl group, or an alkoxycarbonyl group.

Z ⁻ represents a counter anion, for example, a perfluoroalkanesulfonic acid anion such as BF ₄ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , Si F 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.

  The above onium salts represented by the general formula (PAG1) or (PAG2) are known and can be synthesized, for example, by the methods described in U.S. Pat. Nos. 2,807,648 and 4,247,473, JP-A-53-101,331, and the like.

  (2) A disulfone derivative represented by the following general formula (PAG3) or an iminosulfonate derivative represented by the general formula (PAG4).

In the formula, Ar ³ and Ar ⁴ each independently represent an aryl group.
R ²⁰⁶ represents an alkyl group, a cycloalkyl 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.

  (3) A diazodisulfone derivative represented by the following general formula (PAG5).

  Here, R independently represents an alkyl group, a cycloalkyl group, or an aryl group. Specific examples include the following compounds, but are not limited thereto.

  In addition to the above compounds, compounds represented by the following general formula (PAG6) are also effectively used.

式（ＰＡＧ６）中、
Ｒ₁〜Ｒ₅は、水素原子、アルキル基、アルコキシ基、ニトロ基、ハロゲン原子、アルキルオキシカルボニル基又はアリール基を表し、Ｒ₁〜Ｒ₅のうち少なくとも２つ以上が結合して環構造を形成してもよい。
Ｒ₆及びＲ₇は、水素原子、アルキル基、シアノ基又はアリール基を表す。
Ｙ₁及びＹ₂は、アルキル基、シクロアルキル基、アリール基、アラルキル基又はヘテロ原子を含む芳香族基を表し、Ｙ₁とＹ₂とが結合して環を形成してもよい。
Ｙ₃は、単結合または２価の連結基を表す。
Ｘ^-は、非求核性アニオンを表す。
但し、Ｒ₁からＲ₅の少なくとも１つとＹ₁又はＹ₂の少なくとも一つが結合して環を形成するか、若しくは、Ｒ₁からＲ₅の少なくとも１つとＲ₆又はＲ₇の少なくとも１つが結合し
て環を形成する。
尚、Ｒ₁からＲ₇のいずれか、若しくは、Ｙ₁又はＹ₂のいずれかの位置で、連結基を介して結合し、式（ＰＡＧ６）の構造を２つ以上有していてもよい。

In the formula (PAG6),
R _{1 to} R ₅ 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 _{1 to} R ₅ are bonded to form a ring structure. It may be formed.
R ₆ and R ₇ represent a hydrogen atom, an alkyl group, a cyano group, or an aryl group.
Y ₁ and Y ₂ represent an alkyl group, a cycloalkyl 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.
Provided that at least one of R ₁ to R ₅ and at least one of Y ₁ or Y ₂ are bonded to form a ring, or at least one of R ₁ to R ₅ and at least one of R ₆ or R ₇ are bonded. To form a ring.
In addition, it may be bonded via a linking group at any position of R ₁ to R ₇ or at any position of Y ₁ or Y ₂ and may have two or more structures of the formula (PAG6).

The alkyl group represented by R _{1 to} R ₇ is an alkyl group, preferably an alkyl group having 1 to 5 carbon atoms. Examples of the unsubstituted alkyl group include a methyl group, an ethyl group, a propyl group, and n-butyl. Group, sec-butyl group, t-butyl group and the like.
The alkoxy group in R _{1 to} R ₅ and the alkyloxycarbonyl group is preferably an alkoxy group having 1 to 5 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. .
The aryl group of R _{1 to} R ₇ , Y ₁ and Y ₂ is an aryl group, preferably an aryl group having 6 to 14 carbon atoms, and examples thereof include a phenyl group, a tolyl group, and a naphthyl group. .
Examples of the halogen atom represented by R _{1 to} R ₅ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The alkyl group as Y ₁ and Y ₂ is preferably an alkyl group having 1 to 30 carbon atoms, such as methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group, t-butyl group, etc. Can be mentioned.
The cycloalkyl group as Y ₁ and Y ₂ preferably has 3 to 30 carbon atoms, and examples thereof include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, a norbornyl group, and a boronyl group.

The aralkyl group of Y ₁ and Y ₂ is preferably an aralkyl group having 7 to 12 carbon atoms, and examples of the unsubstituted aralkyl group include a benzyl group, a phenethyl group, and a cumyl group.

The aromatic group containing a hetero atom represents a group having a hetero atom, for example, a nitrogen atom, an oxygen atom, a sulfur atom, etc. in an aromatic group such as an aryl group having 6 to 14 carbon atoms.
The aromatic group containing a hetero atom of Y ₁ and Y ₂ is an aromatic group containing a hetero atom, and examples of the unsubstituted group include heterocyclic aromatics such as furan, thiophene, pyrrole, pyridine, and indole. Group hydrocarbon group.

Y ₁ and Y ₂ may combine to form a ring together with S ⁺ in formula (PAG6).
In this case, examples of the group formed by combining Y ₁ and Y ₂ include an alkylene group having 4 to 10 carbon atoms, preferably a butylene group, a pentylene group, and a hexylene group, and particularly preferably a butylene group and a pentylene group. Can be mentioned.
In addition, a ring formed by combining Y ₁ and Y ₂ together with S ⁺ in formula (PAG6) may contain a hetero atom.

  Each of the above alkyl group, cycloalkyl group, alkoxy group, alkoxycarbonyl group, aryl group, and aralkyl group is, for example, nitro group, halogen atom, carboxyl group, hydroxyl group, amino group, cyano group, alkoxy group (preferably carbon It may be substituted with formulas 1 to 5). Furthermore, the ring structure in a cycloalkyl group, an aryl group, and an aralkyl group can further include an alkyl group (preferably having 1 to 5 carbon atoms) as a substituent. Moreover, as a substituent of an alkyl group, a halogen atom is preferable.

Y ₃ represents a single bond or a divalent linking group, and examples of the divalent linking group include an alkylene group, an alkenylene group, —O—, —S—, —CO—, —CONR— (R represents a hydrogen atom And a linking group that may contain two or more of them is preferable.

Examples of the non-nucleophilic anion X ⁻ include a sulfonate anion and a carboxylate anion.
A non-nucleophilic anion is an anion that has an extremely low ability to cause a nucleophilic reaction and is an anion that can suppress degradation over time due to an intramolecular nucleophilic reaction. This improves the temporal stability of the resist.
Examples of the sulfonate anion include an alkyl sulfonate anion, an aryl sulfonate anion, and a camphor sulfonate anion.
Examples of the carboxylate anion include an alkylcarboxylate anion, an arylcarboxylate anion, and an aralkylcarboxylate anion.

The alkyl group in the alkylsulfonate anion is preferably an alkyl group having 1 to 30 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, or a pentyl group. , Neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, cyclo Examples thereof include a propyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, a norbornyl group, and a boronyl group.
The aryl group in the aryl sulfonate anion is preferably an aryl group having 6 to 14 carbon atoms, such as a phenyl group, a tolyl group, and a naphthyl group.

The alkyl group and aryl group in the alkyl sulfonate anion and aryl sulfonate anion may have a substituent.
Examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, and an alkylthio group.

Examples of the halogen atom include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom.
As the alkyl group, for example, preferably an alkyl group having 1 to 15 carbon atoms, for example, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, pentyl group, neopentyl group Hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, etc. it can.
As an alkoxy group, Preferably a C1-C5 alkoxy group, for example, a methoxy group, an ethoxy group, a propoxy group, a butoxy group etc. can be mentioned, for example.
As the alkylthio group, for example, preferably an alkylthio group having 1 to 15 carbon atoms, for example, methylthio group, ethylthio group, propylthio group, isopropylthio group, n-butylthio group, isobutylthio group, sec-butylthio group, pentylthio group, Neopentylthio group, hexylthio group, heptylthio group, octylthio group, nonylthio group, decylthio group, undecylthio group, dodecylthio group, tridecylthio group, tetradecylthio group, pentadecylthio group, hexadecylthio group, heptadecylthio group, octadecylthio group, nonadecylthio group Group, eicosylthio group and the like. The alkyl group, alkoxy group, and alkylthio group may be further substituted with a halogen atom (preferably a fluorine atom).

Examples of the alkyl group in the alkylcarboxylate anion include the same alkyl groups as in the alkylsulfonate anion.
Examples of the aryl group in the arylcarboxylate anion include the same aryl groups as in the arylsulfonate anion.
The aralkyl group in the aralkylcarboxylate anion is preferably 6 to 6 carbon atoms.
12 aralkyl groups such as benzyl group, phenethyl group, naphthylmethyl group, naphthylethyl group, naphthylmethyl group and the like can be mentioned.

  The alkyl group, aryl group and aralkyl group in the alkylcarboxylate anion, arylcarboxylate anion and aralkylcarboxylate anion may have a substituent. Examples of the substituent are the same as those in the arylsulfonate anion. A halogen atom, an alkyl group, an alkoxy group, an alkylthio group, etc. can be mentioned.

  Examples of other non-nucleophilic anions include fluorinated phosphorus, fluorinated boron, and fluorinated antimony.

In the formula (PAG6) of the present invention, at least one of R ₁ to R ₅ and at least one of Y ₁ or Y ₂ are bonded to form a ring, or at least one of R ₁ to R ₅ At least one of R _{6 and} R ₇ is bonded to form a ring. The compound represented by the formula (PAG6) has a three-dimensional structure and improves optical resolution by forming a ring.
In addition, it may be bonded via a linking group at any position of R ₁ to R ₇ , or any position of Y ₁ or Y ₂ , and may have two or more structures of the formula (PAG6).

  Specific examples of the compound represented by the above formula (PAG6) are shown below, but are not limited thereto.

In the present invention, as a compound that generates an acid upon irradiation with an actinic ray or radiation, an onium salt compound represented by the general formula (PAG1) or (PAG2) and other non-onium salt compounds are used. It is preferable to use together.
In the present invention, it is preferable to use two or more compounds having different transmittances for exposure at a wavelength of 193 nm as a compound that generates an acid upon irradiation with actinic rays or radiation.
In the present invention, as the compound that generates an acid upon irradiation with actinic rays or radiation, it is preferable to use in combination two or more compounds having different carbon chain lengths of the acid generated upon irradiation with actinic rays or radiation.
In the present invention, it is preferable to use two or more kinds of compounds having different acid strengths generated by irradiation with actinic rays or radiation in combination as the compounds generating acid upon irradiation with actinic rays or radiation.

  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 20% by mass, and further preferably 1 to 15% by mass based on the total solid content of the resist composition.

  Among the acid generators used in the present invention, examples of particularly preferable ones are listed below.

[3] (D) Organic Basic Compound A preferred organic basic compound that can be used in the present invention is a compound that is more basic 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 are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, Here, R ²⁵¹ and R ²⁵² may combine with each other to form a ring.
^Examples of the substituent that each group as R ²⁵⁰ , R ²⁵¹ and R ²⁵² may have include an amino group and a hydroxyl group.

(In the formula, R ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R ²⁵⁶ each independently represents an alkyl group or cycloalkyl 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 preferred are compounds containing both an amino group and a ring structure containing a nitrogen atom, or alkylamino A compound having a group. Preferred examples include guanidine, aminopyridine, aminoalkylpyridine, aminopyrrolidine, indazole, pyrazole, pyrazine, pyrimidine, purine, imidazoline, pyrazoline, piperazine, piperidine, aminomorpholine, aminoalkylmorpholine and the like. These may have a substituent, and preferred substituents include amino, aminoalkyl, alkylamino, aminoaryl, arylamino, alkyl, alkoxy, acyl, acyloxy, aryl Group, aryloxy group, nitro group, hydroxyl group, cyano group and the like.

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- Mino piperidine, 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, cyclohexylmorpholinoethylthiourea (CHMETU) Tertiary morpholine derivatives such as hindered armami described in JP-A-11-52575 (For example, those described in the publication [0005]) and the like, but is not limited thereto.

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, And hindered amines such as 2,2,6,6-pentamethyl-4-piperidyl) sebagate.
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 are preferred.

  An organic basic compound is used individually or in combination of 2 or more types. The usage-amount of an organic 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%. In order to obtain a sufficient addition effect, 0.001% by mass or more is preferable, and 10% by mass or less is preferable in terms of sensitivity and developability of the non-exposed area.

[4] Surfactant The resist composition of the present invention comprises a surfactant, particularly a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant and silicon-based surfactant, both fluorine atom and silicon atom). It is preferable to contain any one or two or more surfactants.
When the resist composition of the present invention contains a fluorine-based and / or silicon-based surfactant, when using an exposure light source of 250 nm or less, particularly 220 nm or less, good sensitivity and resolution, and less adhesion and development defects. A resist pattern can be provided.
As these surfactants, for example, JP-A-62-36663, JP-A-61-226746, JP-A-61-226745, JP-A-62-170950, JP-A-63-34540 No. 7, JP-A-7-230165, JP-A-8-62834, JP-A-9-54432, JP-A-9-5988, JP-A 2002-277862, US Pat. No. 5,405,720. , No. 5,360,692, No. 5,529,881, No. 5,296,330, No. 5,543,098, No. 5,576,143, No. 5,294,511, No. 5,824,451. The following commercially available surfactants can also be used as they are.
Examples of commercially available surfactants that can be used include F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189, R08 (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.), etc. Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

In addition to the known surfactants described above, surfactants are derived from fluoroaliphatic compounds produced by the telomerization method (also referred to as the telomer method) or the oligomerization method (also referred to as the oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.
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). It may be 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. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates).
Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxy) Copolymer) of (ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate), 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, based on the total amount of the resist composition (excluding the solvent).

[5] Solvent The resist composition of the present invention is obtained by dissolving the above-described components in a solvent.
In the present invention, a mixed solvent containing at least one of propylene glycol monomethyl ether carboxylate and alkyl lactate and a cyclic ketone solvent (hereinafter, these solvents are also referred to as specific solvents) is used as the solvent.

  Examples of the cyclic ketone include a total carbon number of 5 such as cyclopentanone, 3-methyl-2-cyclopentanone, cyclohexanone, 2-methylcyclohexanone, 2,6-dimethylcyclohexanone, cycloheptanone, cyclooctanone, isophorone and the like. -8 compounds and the like can be mentioned. Cyclohexanone and cycloheptanone are preferable.

  Specific examples of the propylene glycol monoalkyl ether carboxylate include propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether acetate and the like, and examples of the alkyl lactate include methyl lactate and ethyl lactate. Can do.

  The ratio (mass ratio) of the total amount of propylene glycol monomethyl ether carboxylate and alkyl lactate and cyclic ketone is preferably 95/5 to 30/70, more preferably 90/10 to 40/60, and particularly preferably 90/10. 60/40.

Other solvents other than the specific solvent may be contained, and examples of other solvents include propylene glycol monoalkyl ether, alkyl alkoxypropionate, and linear ketone.
Examples of the propylene glycol monoalkyl ether include propylene glycol monomethyl ether and propylene glycol monoethyl ether. Examples of alkyl alkoxypropionate include methyl methoxypropionate, ethyl methoxypropionate, methyl ethoxypropionate, ethyl ethoxypropionate, etc., and examples of linear ketones include methyl ethyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, etc. Can be mentioned.

  In the mixed solvent contained in the resist composition of the present invention, the content of the solvent other than the specific solvent is preferably 20% by mass or less, more preferably 10% by mass or less.

  Using such a mixed solvent, a resist composition having a solid content concentration of usually 3 to 25% by mass, preferably 5 to 22% by mass, and more preferably 5 to 15% by mass is prepared.

  In the resist composition of the present invention, a low-molecular acid decomposable compound, a surfactant, a compound that promotes dissolution in a developer, an antihalation agent, a plasticizer, a photosensitizer, a surfactant, an adhesive, if necessary. An auxiliary agent, a crosslinking agent, a photobase generator and the like can be contained.

The resist composition of the present invention comprises a low-molecular acid-decomposable compound having a molecular weight of 2000 or less, having a group that can be decomposed by the action of an acid, and having an alkali solubility increased by the action of an acid. Can be included.
For example, Proc. SPIE, 2724, 355 (1996), JP-A-8-15865, U.S. Pat.No. 5310619, U.S. Pat.No. 5372912, J. Photopolym. Sci., Tech., Vol. 10, No. 3, 511 ( 1997)), which contains an acid-decomposable group, alicyclic compounds such as cholic acid derivatives, dehydrocholic acid derivatives, deoxycholic acid derivatives, lithocholic acid derivatives, ursocholic acid derivatives, and abietic acid derivatives, acid decomposition An aromatic compound such as a naphthalene derivative containing a functional group can be used as the low-molecular acid-decomposable compound.
Further, the low-molecular acid-decomposable dissolution inhibiting compounds described in JP-A-6-51519 can also be used in an addition range at a level that does not deteriorate the transmittance at 220 nm, and 1,2-naphthoquinone diazite compounds can also be used.

When the low molecular acid decomposable dissolution inhibiting compound is used in the resist composition of the present invention, the content thereof is usually in the range of 0.5 to 50 parts by mass based on 100 parts by mass (solid content) of the resist composition. Preferably 0.5 to 40 parts by mass, more preferably 0.5 to 30 parts by mass, and particularly preferably 0.5 to 20.0 parts by mass.
Addition of these low molecular acid decomposable dissolution inhibiting compounds not only further improves the development defects, but also improves dry etching resistance.

Examples of the dissolution promoting compound that can be used in the present invention include compounds containing two or more phenolic hydroxyl groups described in JP-A-3-206458, one naphthol such as 1-naphthol, or one carboxyl group. Examples thereof include low molecular compounds having a molecular weight of 1000 or less, such as compounds having the above, carboxylic acid anhydrides, sulfonamide compounds and sulfonylimide compounds.
The blending amount of these dissolution promoting compounds is preferably 30% by mass or less, more preferably 20% by mass or less, based on the total mass (solid content) of the composition.

  As a suitable antihalation agent, a compound that efficiently absorbs irradiated radiation is preferable, and substituted benzenes such as fluorene, 9-fluorenone, and benzophenone; anthracene, anthracene-9-methanol, anthracene-9-carboxyethyl, phenanthrene , Polycyclic aromatic compounds such as perylene and azylene. Of these, polycyclic aromatic compounds are particularly preferred. These antihalation agents exhibit the effect of improving standing waves by reducing the reflected light from the substrate and reducing the influence of multiple reflections in the resist film.

  Moreover, in order to improve the acid generation rate by exposure, a photosensitizer can be added. Suitable photosensitizers include benzophenone, p, p′-tetramethyldiaminobenzophenone, 2-chlorothioxanthone, anthrone, 9-ethoxyanthracene, pyrene, phenothiazine, benzyl, benzoflavine, acetophenone, phenanthrene, benzoquinone, anthraquinone, 1 , 2-naphthoquinone and the like, but are not limited thereto. These photosensitizers can also be used as the antihalation agent.

[6] Pattern Forming Method The resist composition of the present invention is used by dissolving the above components in a solvent, preferably the mixed solvent, and applying the solution on a predetermined support as follows.
That is, the resist composition is applied onto a substrate (eg, silicon / silicon dioxide coating) used in the manufacture of precision integrated circuit elements by an appropriate application method such as a spinner or coater, and dried to form a resist film. To do.
The resist film is exposed through a predetermined mask, preferably baked and developed. In this way, a good positive resist pattern can be obtained. Here, the exposure light is preferably far ultraviolet rays having a wavelength of 250 nm or less, more preferably 220 nm or less. 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 alkaline developer used in development include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, and primary amines such as ethylamine and n-propylamine. Secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide and the like Alkaline aqueous solutions (usually 0.1 to 10% by mass) such as quaternary ammonium salts, cyclic amines such as pyrrole and pihelidine can be used.
Furthermore, alcohols and surfactants can be added in appropriate amounts to the alkaline aqueous solution.

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

Synthesis Example (1) Synthesis of Resin (1) 2-Adamantyl-2-propyl acrylate, butyrolactone methacrylate, and hydroxyadamantane methacrylate were charged at a ratio (molar ratio) of 50/30/20, methyl ethyl ketone / tetrahydrofuran = 5/5 (mass ratio). ) To prepare 100 mL of a solution having a solid content concentration of 20% by mass. To this solution, 2 mol% of a polymerization initiator V-65 manufactured by Wako Pure Chemical Industries, Ltd. was added, and this was added dropwise to 10 mL of methyl ethyl ketone heated to 60 ° C. over 4 hours in a nitrogen atmosphere. After completion of the dropwise addition, the reaction solution was heated for 4 hours, 1 mol% of V-65 was added again, and the mixture was stirred for 4 hours. After completion of the reaction, the reaction solution was cooled to room temperature, and the resin (1), which was a white powder crystallized and precipitated in 3 L of a mixed solvent of distilled water / isopropyl alcohol = 1/1 (mass ratio), was recovered.
The polymer composition ratio (molar ratio) determined from C ¹³ NMR was 45/32/23. Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 10700.
Resins (2) to (10) were synthesized in the same manner as in Synthesis Example (1) except that the monomers and composition ratios shown in Table 1 were used. The repeating units 1, 2, 3, 4 are in order from the left of the structural formula.

Synthesis of Comparative Resin (R1) Comparative resin (R1) having the following repeating units was synthesized by the same operation as in Synthesis Example (1). Repeat units 1, 2, and 3 are the order from the left of the structural formula.

  The structures of the resins (1) to (10) and the comparative resin (R1) are shown below.

   The following compounds 1 and 2 were used as the compound represented by the general formula (1) (photoacid generator).

[Examples 1 to 19 and Comparative Examples 1 to 4]
(Preparation and evaluation of resist composition)
Each component described in Table 2 is dissolved in a solvent so that the total solid content is 10% by mass in the mass ratio described in the table, and filtered through a microfilter having a pore size of 0.1 μm to prepare a resist composition. did. However, 0.3 parts by mass of the nitrogen-containing basic compound and 100 ppm of the total amount of the resist were used.

[Nitrogen-containing basic compound]
N-1: 1,5-diazabicyclo [4.3.0] non-5ene N-2: trioctylamine N-3: N, N-di-n-butylaniline N-4: adamantylamine N-5 : 2,5-diisopropylaniline

[Surfactant]
W-1: Megafuck F176
(Dainippon Ink & Chemicals, Inc .; fluorinated activator)
W-2: Mega Fuck R08
(Dainippon Ink & Chemicals, Inc .; fluorine / silicone activator)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.)
W-4: Troisol S-366 (manufactured by Troy Chemical Co., Ltd.)
〔solvent〕
S1: Propylene glycol monomethyl ether acetate S2: Cyclohexanone S3: Cyclopentanone

[Formation of resist pattern]
ARC29a manufactured by Brewer Science Co., Ltd. was uniformly applied to a silicon wafer with a spin coater at 780 Å, followed by heating and drying at 205 ° C. for 60 seconds to form an antireflection film. Then, each resist composition immediately after preparation was applied with a spin coater and dried at 115 ° C. for 90 seconds to form a 360 nm resist film.
This resist film was exposed with an ArF excimer laser stepper (NA = 0.6 (3/4 annular illumination) manufactured by ISI) through a mask, and heated on a hot plate at 115 ° C. for 90 seconds immediately after the exposure. The resist line pattern was obtained by developing with a 38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 60 seconds, rinsing with pure water for 30 seconds, and drying.

[sensitivity]
Using a binary mask with a coverage of 50%, the exposure amount for reproducing a 130 nm line pattern (line: space = 1: 1) was defined as sensitivity.

[Mask coverage dependency]
Using two types of binary masks with a coverage of 50% and a coverage of 95%, pattern exposure is performed using an ArF stepper, development is performed as described above, a pattern is formed and observed, and a 130 nm line pattern (line : Space = 1: 1) was calculated for a wafer exposed with two masks having a coverage of 50% and a coverage of 95%. The coverage dependency is a value calculated based on the following equation.
Coverage dependency (mJ / cm ² ) = (Exposure amount when using a mask with a coverage of 95%) − (Exposure amount when using a mask with a coverage of 50%)
The smaller the value of the coverage dependency obtained by the above formula means that the sensitivity change due to the coverage change is small and the performance is good.
The results are shown in Table 2.

  As is apparent from the results in Table 2, it can be seen that the resist composition of the present invention has high sensitivity and small coverage dependency.

Claims (4)

(A) A resin having a repeating unit represented by formula (I), which decomposes by the action of an acid and increases the dissolution rate in an alkaline developer, and (B) generates an acid upon irradiation with actinic rays or radiation. A compound represented by the following general formula (1), and
(C) A resist composition containing a mixed solvent containing at least one of propylene glycol monomethyl ether carboxylate and alkyl lactate and a cyclic ketone solvent.

In general formula (I), R ₃₀ represents a hydrogen atom or a methyl group.
R _{31 to} R ₃₃ each independently represents a hydrogen atom, a hydroxyl group or an alkyl group, provided that at least one represents a hydroxyl group.

In general formula (1), R ₁ and R ₂ each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, or a cyano group. R ₁ and R ₂ may combine to form a ring.
R ₃ represents an alkyl group, a cycloalkyl group or an aryl group having a fluorine atom.
R ₁ and R ₂ may be bonded to R ₁ or R ₂ of another compound represented by the general formula (1) through a single bond or a linking group.   The resist composition according to claim 1, further comprising a nitrogen-containing basic compound.   The resist composition according to claim 1, further comprising a sulfonium salt compound that generates an acid upon irradiation with an actinic ray or radiation.   A pattern forming method comprising: forming a resist film from the resist composition according to claim 1; and exposing and developing the resist film.