JP4360957B2 - Positive resist composition and pattern forming method using the same - Google Patents

Description

  The present invention relates to a positive resist composition used in a semiconductor manufacturing process such as an IC, a circuit board such as a liquid crystal or a thermal head, and other photofabrication processes, and a pattern forming method using the same. . More specifically, the present invention relates to a positive resist composition suitable for use as an exposure light source such as far ultraviolet rays of 250 nm or less and an irradiation source using an electron beam, and a pattern forming method using the same.

  The chemically amplified positive resist composition generates an acid in the exposed area by irradiation with radiation such as far ultraviolet light, and dissolves in the developing solution of the active radiation irradiated area and the non-irradiated area by a reaction using this acid as a catalyst. It is a pattern forming material that changes the properties and forms the pattern on the substrate.

  When a KrF excimer laser is used as an exposure light source, a resin having a basic skeleton of poly (hydroxystyrene) having a small absorption mainly in the region of 248 nm is used as a main component. A pattern is formed, which is a better system than the conventional naphthoquinone diazide / novolak resin system.

  On the other hand, when a further short wavelength light source, for example, an ArF excimer laser (193 nm) is used as an exposure light source, the compound having an aromatic group exhibits a large absorption in the 193 nm region. It wasn't.

For this reason, an ArF excimer laser resist containing a resin having an alicyclic hydrocarbon structure has been developed.
Patent Document 1 (Japanese Patent Laid-Open No. 10-254139) provides a radiation-sensitive resin composition excellent in radiation transparency, dry etching resistance, film thickness uniformity, substrate adhesion, sensitivity, resolution, developability, and the like. Therefore, the use of a solvent comprising a mixture of a linear ketone and at least one selected from the group of cyclic ketone, propylene glycol monoalkyl ether acetate and alkyl 2-hydroxypropionate is described.
Patent Document 2 (Japanese Patent Application Laid-Open No. 2002-229192) is a radiation-sensitive acid generator in order to provide a radiation-sensitive resin composition that has high transparency to deep ultraviolet light and is excellent in sensitivity, resolution, pattern shape, and the like. It proposes the use of certain compounds having a cyclic sulfonium structure and a benzene ring or naphthalene ring.
Patent Document 3 (Japanese Patent Laid-Open No. 2001-142212) describes a specific resin having an alicyclic structure and propylene glycol monomethyl ether acetate as a resist composition with improved sensitivity, resolution, adhesion to a substrate, and edge roughness of a pattern. A composition containing the following specific solvents is disclosed.

Various resists have been proposed in this way, but further improvement in performance has been desired for line edge roughness and common defocus latitude of isolated lines, dense lines, and isolated trenches.
Line edge roughness means that the resist line pattern and the edge of the substrate interface exhibit irregularly varying shapes in a direction perpendicular to the line direction due to the characteristics of the resist. When this pattern is observed from directly above, the edges appear to be uneven (approximately ± several tens of nm). Since the unevenness is transferred to the substrate by an etching process, if the unevenness is large, an electrical characteristic defect is caused and the yield is lowered. With the miniaturization of the pattern size, there is an increasing demand for improvement in line edge roughness.
The defocus latitude is the tolerance of defocus during exposure, and it is desirable that the same size pattern be obtained even if the focus fluctuates to some extent. The common defocus latitude of isolated lines, dense lines, and isolated trenches is a focus shift that can be allowed at the same time for the three different types of fine patterns, and is different from a single one. In other words, the resist compositions disclosed so far can improve the performance of one or two of the above-mentioned patterns, but it is difficult to increase the focus shift that allows the three patterns simultaneously, It has been desired to improve the common defocus latitude of isolated lines, dense lines, and isolated trenches.

Japanese Patent Laid-Open No. 10-254139 JP 2002-229192 A JP 2001-142212 A

  Accordingly, an object of the present invention is to use a positive resist composition that has a small line edge roughness even in the formation of a fine pattern and a wide defocus latitude in various patterns such as a sparse or dense pattern, a line or a trench pattern, and the like. Another object of the present invention is to provide a pattern forming method.

  The present invention is a positive resist composition having the following constitution and a pattern forming method using the same, whereby the above object of the present invention is achieved.

(1) (A) A repeating unit containing at least one acrylic ester derivative repeating unit represented by general formula (IV) and groups represented by general formulas (V-1) to (V-4) The solubility in an alkali developer is increased by the action of an acid having a glass transition temperature of 70 to 155 ° C., which contains at least one selected from repeating units having a repeating unit represented by formula (AII) Resin,
(B) a compound that generates an acid upon irradiation with actinic rays or radiation, and
(C) at least one selected from propylene glycol monoalkyl ether carboxylate, alkyl lactate and linear ketone, and selected from cyclopentanone, 3-methylcyclopentanone, cyclohexanone, 2-methylcyclohexanone and 2,6-dimethylcyclohexanone A positive resist composition comprising a mixed solvent containing at least one cyclic ketone .

In the general formula (IV), R ₁ a 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.
Ra ₁ , Rb ₁ , Rc ₁ , Rd ₁ and Re ₁ 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 = 2 to 6.

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 general formula (AII), R _1c represents a hydrogen atom or a methyl group.
R _{2c to} R _4c each independently represents a hydrogen atom or a hydroxyl group. However, at least one of R _{2c to} R _4c represents a hydroxyl group.

(1 ′) The resist composition as described in (1) above, wherein the cyclic ketone contained in the mixed solvent is at least one selected from cyclopentanone, cyclohexanone and 2-methylcyclohexanone.
(2) The resist composition as described in (1) or (1 ′) above, wherein 10 to 90 mol% of the repeating units constituting the resin (A) are derived from an acrylate monomer.

(3) The resist composition as described in any one of (1) to (2) above, wherein 50 to 75 mol% of the repeating units constituting the resin (A) are derived from an acrylate monomer.

(4) The resist composition as described in any one of (1) to (3) above, wherein the compound (B) is a triphenylsulfonium salt.

(5) The resist composition as described in any one of (1) to (3) above, wherein the compound (B) is a phenacylsulfonium salt.

Further preferred embodiments include the following configurations.
(6) The resist composition as described in any one of (1) to (5) above, wherein the organic solvent (C) contains a cyclic ketone in an amount of 20 to 70% by mass of the total organic solvent.

(7) The resist composition as described in any one of (1) to (5) above, wherein the organic solvent (C) contains a cyclic ketone in an amount of 30 to 60% by mass of the total organic solvent.

(8) The resist composition as described in any one of (1) to (7) above, wherein the resin (A) has an alkali-soluble group protected by a 1-adamantyl-1-alkyl group.
(9) A pattern forming method comprising: forming a resist film from the resist composition according to any one of (1) to (8) above; and exposing and developing the resist film.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a positive resist composition having a good performance capable of dealing with various patterns with a small edge roughness, a large defocus latitude, and a pattern forming method using the same.

Hereinafter, the compounds used in the present invention will be described in detail. The present invention relates to the above (1) to (9), but will be described below including other matters for reference.

[1] Resin that increases the solubility in an alkaline developer by the action of an acid (component A)
Resin (A) contains at least one repeating unit of an acrylate derivative, a repeating unit represented by general formula (IV) and groups represented by general formulas (V-1) to (V-4) The solubility in an alkali developer is increased by the action of an acid having a glass transition temperature of 70 to 155 ° C., which contains at least one selected from repeating units having a repeating unit represented by formula (AII) Resin (acid-decomposable resin).
The resin (A) may contain a repeating unit derived from a methacrylic ester derivative as long as it contains a repeating unit derived from at least one acrylate derivative. In the present invention, the repeating unit derived from the acrylate derivative also includes a repeating unit derived from acrylic acid itself.

  The repeating unit derived from the acrylate derivative contained in the resin (A) may be any repeating unit constituting the resin (A). The repeating unit represented by the general formula (IV) is represented by the general formula (V The repeating unit which has group represented by -1)-(V-4), and the repeating unit represented by general formula (AII) may be sufficient.

Resin (A) is a repeating unit having a lactone structure selected from repeating units represented by general formula (IV) and repeating units having groups represented by general formulas (V-1) to (V-4). Contains at least one.
First, the repeating unit represented by the general formula (IV) will be described.

In general formula (IV), R ₁ a 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.
Ra ₁ , Rb ₁ , Rc ₁ , Rd ₁ and Re ₁ 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 Ra _{1 to} Re ₁ 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 for 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.

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

In the specific example of the general formula (IV), (IV-17) to (IV-36) are preferable because the exposure margin becomes better.
Further, as the structure of the general formula (IV), those having an acrylate structure are preferable from the viewpoint that the edge roughness becomes good.

  Next, the repeating unit having a group represented by any one of the general formulas (V-1) to (V-4) will be described.

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, cycloalkyl group, or alkenyl group as R _{1b to} R _5b includes those each having a substituent.
Examples of the alkyl group in R _{1b to} R _5b include linear and branched alkyl groups, including those having a substituent. 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. 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 It is a 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 (AI).

In general formula (AI), R _b0 represents a hydrogen atom, a halogen atom, or a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms. As a preferable substituent which the alkyl group of R _b0 may have, as a preferable substituent which the alkyl group as R _1b in the general formulas (V-1) to (V-4) may have. What was illustrated previously is mentioned.
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 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.

  Although the specific example of the repeating unit represented by general formula (AI) is given to the following, the content of this invention is not limited to these.

  The resin (A) further contains a repeating unit represented by the following general formula (AII).

In general formula (AII), R _1c represents a hydrogen atom or a methyl group.
R _{2c to} R _4c each independently represents a hydrogen atom or a hydroxyl group. However, at least one of R _{2c to} R _4c represents a hydroxyl group.
Two of R _{2c to} R _4c are preferably hydroxyl groups.

  Although the specific example of the repeating unit which has a structure represented by general formula (AII) below is given, it is not limited to these.

Resin (A) is a resin whose solubility in an alkaline developer is increased by the action of an acid (hereinafter also referred to as “acid-decomposable resin”), and is insoluble or hardly soluble in an alkali developer. Contains a repeating unit having a group (acid-decomposable group) that is decomposed by alkali to become alkali-soluble.
The resin (A) particularly preferably contains a repeating unit having a partial structure containing an alicyclic hydrocarbon represented by the following general formula (pI) to general formula (pVI) as an acid-decomposable group.

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 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.
Further, the further substituent of the alkyl group includes 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 _{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 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. To express. 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.

The structures represented by the general formulas (pI) to (pVI) in the resin can be used for protecting alkali-soluble groups. Examples of the alkali-soluble group include various groups known in this technical field.
Specific examples include a carboxylic acid group, a sulfonic acid group, a phenol group, and a thiol group, and a carboxylic acid group and a sulfonic acid group are preferable.
As the alkali-soluble group (acid-decomposable group) protected by the structure represented by the general formulas (pI) to (pVI) in the resin, groups represented by the following general formulas (pVII) to (pXI) are preferable. Can be mentioned.

Here, R _{11 to} R ₂₅ and Z are the same as defined above.
In the resin, the repeating unit having an alkali-soluble group protected by the structure represented by the general formulas (pI) to (pVI) is preferably a repeating unit represented by the following general formula (pA).

Here, R represents a hydrogen atom, a halogen atom, or a substituted or unsubstituted linear or branched alkyl group having 1 to 4 carbon atoms. A plurality of R may be the same or different.
A is a single bond, an alkylene group, a substituted alkylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a sulfonamide group, a urethane group, or a urea group. Represents a combination of groups.
Ra represents any group of the above formulas (pI) to (pVI).

  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 1-adamantyl-1-alkyl group, and the 1-adamantyl-1-alkyl group It is more preferable to have a protected alkali-soluble group.

  The resin (A) may have an acid-decomposable group as a partial structure containing the alicyclic hydrocarbon represented by the general formula (pI) to the general formula (pVI), or a repeating copolymer component described later. You may have in at least 1 type of repeating unit among units.

As the structure of the acid-decomposable group, in addition to the alkali-soluble group (acid-decomposable group) protected by the structure represented by the general formulas (pI) to (pVI), for example, —C (═O) — it can be exemplified those represented by X ₁ -R _0.
In the formula, R ₀ is a tertiary alkyl group such as t-butyl group or 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, 3-oxoalkyl group, tetrahydropyranyl group, tetrahydrofuranyl group, trialkylsilyl ester group, 3- Examples include an oxocyclohexyl ester group, a 2-methyl-2-adamantyl group, a mevalonic lactone residue, and the like. X ₁ represents an oxygen atom, a sulfur atom, -NH -, - NHSO ₂ - or an -NHSO ₂ NH-.

  The resin (A) can further contain a 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 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 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.
In the general formula (VI), examples of the cycloalkylene group represented by A ₆ 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 ₆ 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 ( For example, propylcarbonyloxy group, benzoyloxy group), alkyl group (preferably having 1 to 4 carbon atoms), carboxyl group, hydroxyl group, alkylsulfonylsulfamoyl group (-
CONHSO ₂ CH ₃ etc.). 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.

  Resin (A) adjusts dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general required properties of resist, such as resolution, heat resistance, and sensitivity, in addition to the above repeating units. Various repeating units can be contained for the purpose.

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

Specifically, the following monomers can be mentioned.
Acrylic acid esters (preferably alkyl acrylates having an alkyl group with 1 to 10 carbon atoms):
Methyl acrylate, ethyl acrylate, propyl acrylate, amyl acrylate, cyclohexyl acrylate, ethyl hexyl acrylate, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate 2,2-dimethylhydroxy Propyl acrylate, 5-hydroxypentyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, and the like.

Methacrylic acid esters (preferably alkyl methacrylate having 1 to 10 carbon atoms in the alkyl group):
Methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, chlorobenzyl methacrylate, octyl methacrylate, 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 2 , 2-dimethyl-3-hydroxypropyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate and the like.

Acrylamides:
Acrylamide, N-alkylacrylamide (alkyl group having 1 to 10 carbon atoms, such as methyl group, ethyl group, propyl group, butyl group, t-butyl group, heptyl group, octyl group, cyclohexyl group, hydroxyethyl group, etc. N, N-dialkylacrylamide (alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, butyl, isobutyl, ethylhexyl, cyclohexyl, etc.), N-hydroxy Ethyl-N-methylacrylamide, N-2-acetamidoethyl-N-acetylacrylamide and the like.

Methacrylamide:
Methacrylamide, N-alkylmethacrylamide (alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, t-butyl, ethylhexyl, hydroxyethyl, cyclohexyl, etc.), N, N -Dialkylmethacrylamide (there are alkyl groups such as ethyl group, propyl group, butyl group), N-hydroxyethyl-N-methylmethacrylamide and the like.

Allyl compounds:
Allyl esters (for example, allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, etc.), allyloxyethanol and the like.

Vinyl ethers:
Alkyl vinyl ethers (eg hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethyl hexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether, hydroxyethyl vinyl ether, Diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether and the like.

Vinyl esters:
Vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valerate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, vinyl butoxyacetate, vinyl acetoacetate, vinyl lactate, vinyl -Β-phenylbutyrate, vinylcyclohexylcarboxylate and the like.

Dialkyl itaconates:
Dimethyl itaconate, diethyl itaconate, dibutyl itaconate, etc.
Dialkyl esters or monoalkyl esters of fumaric acid; dibutyl fumarate and the like.

  Others include crotonic acid, itaconic acid, maleic anhydride, maleimide, acrylonitrile, methacrylonitrile, maleilonitrile and the like.

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

  In acid-decomposable resins, the molar ratio of each repeating unit is the resist dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general resist performance required for resolution, heat resistance, sensitivity, etc. It is set appropriately to adjust.

The content of the repeating unit represented by the general formula (IV) is preferably 20 to 70 mol%, and more preferably 25 to 60 mol%, based on all repeating units.
The content of the repeating unit having a group represented by formulas (V-1) to (V-4) is preferably 20 to 70 mol%, more preferably 25 to 60 mol%, based on all repeating units. .
The content of the repeating unit represented by formula (AII) is preferably from 5 to 50 mol%, more preferably from 10 to 40 mol%, still more preferably from 15 to 35 mol%, based on all repeating units. .
The content of the repeating unit derived from the acrylate ester is usually preferably from 10 to 90 mol%, from 20 to 90 mol%, more preferably from 40 to 80 mol%, still more preferably from 50 to 75, based on all repeating units. Mol%.

As for content of the repeating unit which has an acid-decomposable group, 20-60 mol% is preferable with respect to all the repeating units, More preferably, it is 25-55 mol%, More preferably, it is 30-50 mol%.
The content of the repeating unit having a partial structure containing an alicyclic hydrocarbon represented by the general formulas (pI) to (pVI) is preferably 30 to 70 mol%, more preferably 35, based on all repeating units. It is -65 mol%, More preferably, it is 40-60 mol%.

  When the composition of the present invention is for ArF exposure, the 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, A ketone such as methyl isobutyl ketone, an ester solvent such as ethyl acetate, and the composition of the present invention such as propylene glycol monomethyl ether acetate described below are dissolved in a solvent that dissolves uniformly and then nitrogen, argon, etc. Polymerization is started using a commercially available radical initiator (azo initiator, peroxide, etc.) as necessary under an inert gas atmosphere. If desired, an initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery.
The concentration of the reaction is 20% by mass or more, preferably 30% by mass or more, and more preferably 40% by mass or more. The reaction temperature is 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 50-100 ° C.

The repeating structural units represented by the above specific examples may be used singly or in combination.
In the present invention, the resins may be used alone or in combination.

The weight average molecular weight of the resin according to the present invention is preferably 1,000 to 200,000, more preferably 3,000 to 20,000, as a polystyrene converted value by the GPC method. When the weight average molecular weight is less than 1,000, heat resistance and dry etching resistance are deteriorated, which is not preferable. When the weight average molecular weight exceeds 200,000, developability is deteriorated, and the viscosity is extremely high, so that the film forming property is deteriorated. Produces less favorable results.
The dispersity (Mw / Mn) is usually 1 to 10, preferably 1 to 5, more preferably 1 to 4. The smaller the degree of dispersion, the smoother the resolution, resist shape, and resist pattern side walls, and the better the roughness.

The resin used in the present invention contains the specific repeating unit described above, and has a glass transition temperature of 70 to 155 ° C, preferably 70 to 150 ° C, more preferably 80 to 140 ° C, still more preferably 100 to 130 ° C. is there.
The glass transition temperature (Tg) can be measured by differential scanning calorimeter.
In order to obtain a resin containing the above repeating unit and having a glass transition temperature of 70 to 155 ° C., for example, there are the following methods.

In order to control the glass transition point within the specific range, it is necessary not only to introduce the repeating unit having the specific alicyclic structure but also to control the molecular weight and the degree of dispersion (Mw / Mn).
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.
When the weight average molecular weight is less than 5000 or the degree of dispersion exceeds 3.5, the Tg may be lowered and the performance may be lowered in terms of density dependence and side lobe margin.
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 4000 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 composition of this invention contains the compound (photo-acid generator) which generate | occur | produces an acid by irradiation of actinic light or a radiation.
As such a photoacid generator, used as a photoinitiator for photocationic polymerization, a photoinitiator for photoradical polymerization, a photodecolorant for dyes, a photochromic agent, or a microresist, for example, KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (157 nm), known compounds that generate acids upon irradiation with actinic rays or radiation such as X-rays and electron beams, and mixtures thereof are appropriately used. You can select and use.

  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 disulfone compounds and compounds that generate photosulfonic acid by photolysis, such as agents and iminosulfonates.

  Further, a group which generates an acid upon irradiation with these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, for example, US Pat. No. 3,849,137, German Patent No. 3914407, JP 63-26653, JP 55-164824, JP 62-69263, JP 63-146038, JP 63-163452, JP 62-153853, JP 63- The compounds described in No. 146029 and the like can be used.

  Furthermore, compounds capable of generating an acid by light described in US Pat. No. 3,779,778, European Patent 126,712 and the like can also be used.

  Examples of the photoacid generator include the following.

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

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

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

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

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

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

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

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

In the formula, Ar ³ and Ar ⁴ each independently represent a substituted or unsubstituted aryl group.
R ²⁰⁶ represents a substituted or unsubstituted alkyl group or aryl group. A represents a substituted or unsubstituted alkylene group, alkenylene group, or 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 represents a linear, branched or cyclic alkyl group, or an aryl group which may be substituted.
Specific examples include the following compounds, but are not limited thereto.

(B1) Triarylsulfonium Salt In the present invention, a triarylsulfonium salt (B1 component) is particularly preferable as the photoacid generator.

The triarylsulfonium salt is a salt having triarylsulfonium as a cation.
The aryl group of the triarylsulfonium cation is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The three aryl groups of the triarylsulfonium cation may be the same or different.
Each aryl group may have an alkyl group (for example, 1 to 15 carbon atoms), an alkoxy group (for example, 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio group as a substituent. Preferred substituents are alkyl groups having 1 to 8 carbon atoms and alkoxy groups having 1 to 8 carbon atoms, and most preferred are methyl groups, butyl groups, t-butyl groups, and alkoxy groups having 1 to 4 carbon atoms. . The substituent may be substituted with any one of the three aryl groups, or may be substituted with all three. The substituent is preferably substituted at the p-position of the aryl group.
The anion of the triarylsulfonium salt is, for example, a sulfonate anion, preferably an alkane sulfonate anion substituted with a fluorine atom at the 1-position, or a benzene sulfonate substituted with an electron-withdrawing group, more preferably carbon. A perfluoroalkanesulfonic acid anion having a number of 1 to 8, most preferably a perfluorobutanesulfonic acid anion or a perfluorooctanesulfonic acid anion. By using these, the decomposition rate of the acid-decomposable group is improved, the sensitivity is excellent, the diffusibility of the generated acid is controlled, and the resolution is improved.
The triarylsulfonium structure may have a plurality of triarylsulfonium structures bonded to another triarylsulfonium structure through a linking group such as -S-.
Examples of the electron withdrawing group include a fluorine atom, a chlorine atom, a bromine atom, a nitro group, a cyano group, an alkoxycarbonyl group, an acyloxy group, and an acyl group.
Specific examples of the triarylsulfonium salt that can be used in the present invention are shown below, but are not limited thereto.

  Furthermore, the following compounds can be mentioned.

(B2) Moreover, the compound (B2 component) represented by the following general formula (PAG6) is also preferable as a photoacid generator.

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, 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 a substituted or unsubstituted 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, and a propyl group. Group, 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 a substituted or unsubstituted alkoxy group, preferably an alkoxy group having 1 to 5 carbon atoms. Methoxy group, ethoxy group, propoxy group, butoxy group and the like.
The aryl group of R _{1 to} R ₇ , Y ₁ , and Y ₂ is a substituted or unsubstituted aryl group, preferably an aryl group having 6 to 14 carbon atoms. As the unsubstituted aryl group, for example, phenyl Group, tolyl group, naphthyl group and the like.
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 of Y ₁ and Y ₂ is a substituted or unsubstituted alkyl group, preferably an alkyl group having 1 to 30 carbon atoms. Examples of the unsubstituted alkyl group include linear or branched alkyl groups such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, and a t-butyl group, and a cyclopropyl group, Examples thereof include cyclic alkyl groups such as 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 a substituted or unsubstituted aralkyl group, preferably an aralkyl group having 7 to 12 carbon atoms. Examples of the unsubstituted aralkyl group include benzyl group, phenethyl group, cumyl group Groups and the like.

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 substituted or unsubstituted hetero atom. Examples of the unsubstituted group include furan, thiophene, pyrrole, pyridine, and indole. And the heterocyclic aromatic 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 alkyl group, alkoxy group, alkoxycarbonyl group, aryl group, and aralkyl group is, for example, a nitro group, a halogen atom, a carboxyl group, a hydroxyl group, an amino group, a cyano group, or an alkoxy group (preferably having 1 to 5 carbon atoms). ) And the like. Further, the aryl group and aralkyl group may be substituted with an alkyl group (preferably having 1 to 5 carbon atoms).
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 optionally substituted alkylene group, alkenylene group, —O—, —S—, —CO—, —CONR—. (R is hydrogen, an alkyl group, or an acyl group.) And a linking group that may include two or more of these are 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, such as a methylthio group, an ethylthio group, a propylthio group, an isopropylthio group, an n-butylthio group, an isobutylthio group, a sec-butylthio group, a 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 aralkyl carboxylate anion is preferably an aralkyl group having 6 to 12 carbon atoms, such as a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group, and a naphthylmethyl group.

  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 specific example of the acid generator represented by the general formula (PAG6), (PAG6A-1) to (PAG6A-30) and (PAG6B-1) to (PAG6B-12) are more preferable.

  It is particularly preferable to use the component (B1) and the component (B2) in combination, and the ratio in this case is preferably 97/3 to 5/95, more preferably (B1) / (B2) (mass ratio). 90/10 to 10/90, particularly preferably 30/70 to 70/30.

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

  In the present invention, the photoacid generator is particularly preferably a compound that generates perfluorobutanesulfonic acid or perfluorooctanesulfonic acid.

  A photo-acid generator can be used individually by 1 type or in combination of 2 or more types.

  The total amount of the photoacid generator in the positive resist composition of the present invention is preferably 0.1 to 20% by mass, more preferably 0.5 to 20% by mass, and still more preferably, based on the solid content of the composition. Is 1 to 15% by mass.

[3] Organic solvent (component C)
The resist composition of the present invention is obtained by dissolving the above-described components in an organic solvent.
The organic solvent used in the present invention is an organic solvent obtained by mixing a cyclic ketone with at least one selected from propylene glycol monoalkyl ether carboxylate, alkyl lactate and linear ketone.

  With respect to at least one selected from propylene glycol monoalkyl ether carboxylate, alkyl lactate and linear ketone and cyclic ketone, the ratio of addition amount (mass ratio) is preferably 10/90 to 90/10, more preferably 20/80. -80/20, more preferably 30 / 70-70 / 30. The content of the cyclic ketone is preferably 20 to 70% by mass and more preferably 30 to 60% by mass with respect to the total solvent.

Preferred propylene glycol monoalkyl ether carboxylates include propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether acetate, propylene glycol monoethyl ether propionate, and propylene glycol Monomethyl ether acetate is particularly preferred.
As the alkyl lactate, methyl lactate and ethyl lactate are preferable.
Examples of the linear ketone include methyl ethyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, and preferably 2-heptanone.
Examples of cyclic ketones include cyclopentanone, 3-methylcyclopentone, cyclohexanone, 2-methylcyclohexanone, 2,6-dimethylcyclohexanone, isophorone, cycloheptane, 1,3-cycloheptadione, and γ-butyrolactone. Cyclopentanone, 3-methylcyclopentanone, cyclohexanone and cycloheptanone are preferred, and cyclopentanone and cyclohexanone are particularly preferred.

  Furthermore, other organic solvents may be used in combination in the range of usually 10% by mass or less with respect to the specific mixed solvent. Examples of such other organic solvents include ethylene carbonate, propylene carbonate, ethylene dichloride, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, Examples include toluene, ethyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and tetrahydrofuran.

  Using these mixed solvents, a resist composition having a solid content concentration of usually 3 to 25% by mass, preferably 5 to 22% by mass, and more preferably 7 to 20% by mass is prepared.

The positive resist composition of the present invention preferably further contains a nitrogen-containing basic compound.
As the nitrogen-containing basic compound, an organic amine, a basic ammonium salt, a basic sulfonium salt, or the like is used, as long as it does not deteriorate sublimation or resist performance.
Among these nitrogen-containing basic compounds, organic amines are preferred because of excellent image performance. For example, JP-A-63-149640, JP-A-5-249662, JP-A-5-127369, JP-A-5-289322, JP-A-5-249683, JP-A-5-289340, JP-A-5-232706 JP-A-5-257282, JP-A-62-242605, JP-A-6-242606, JP-A-6-266100, JP-A-6-266110, JP-A-6-317902, JP-A-7-120929, JP-A-7-65558, JP-A-7-319163, JP-A-7-508840, JP-A-7-333844, JP-A-7-219217, JP-A-7-92678, JP-A-7-28247, Special Kaihei 8-22120, JP-A-811038, JP-A-8-1223030, JP-A-9-274312, JP-A-9-66871, JP-A-9-292708, JP-A-9-325496, Special table Flat 7-508840, USP5525453, USP5629134, US
The basic compounds described in P5667938 and the like can be used.

 Specific examples of the nitrogen-containing basic compound include structures of the following formulas (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, an aminoalkyl group having 1 to 20 carbon atoms, or 1 to 20 carbon atoms. Or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, wherein R ²⁵¹ and R ²⁵² may combine with each other to form a ring.
R ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R ²⁵⁶ may be the same or different and each represents an alkyl group having 1 to 10 carbon atoms.
Further preferred compounds are nitrogen-containing basic compounds having two or more nitrogen atoms having different chemical environments in one molecule, or aliphatic tertiary amines.

As the nitrogen-containing basic compound, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,4-diazabicyclo is preferable. [2.2.2] Octane, 4-dimethylaminopyridine, 1-naphthylamine, piperidines, hexamethylenetetramine, imidazoles, hydroxypyridines, pyridines, anilines, hydroxyalkylanilines, 4,4′-diamino Diphenyl ether, pyridinium p-toluenesulfonate, 2,4,6-trimethylpyridinium p-toluenesulfonate, tetramethylammonium p-toluenesulfonate, and tetrabutylammonium lactate, triethylamine, tributylamine, tripentylamine, tri-n -Oct And ruamine, tri-i-octylamine, tris (ethylhexyl) amine, tridecylamine, and tridodecylamine.
Among these, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,4-diazabicyclo [2.2.2] Octane, 4-dimethylaminopyridine, 1-naphthylamine, piperidine, 4-hydroxypiperidine, 2,2,6,6-tetramethyl-4-hydroxypiperidine, hexamethylenetetramine, imidazoles, hydroxypyridines, pyridines, aniline 4,4′-diaminodiphenyl ether, triethylamine, tributylamine, tripentylamine, tri-n-octylamine, tris (ethylhexyl) amine, tridodecylamine, N, N-di-hydroxyethylaniline, N-hydroxyethyl Organic amines such as -N-ethylaniline are preferred Yes.

  The use ratio of the acid generator and the nitrogen-containing basic compound in the positive resist composition is usually (acid generator) / (nitrogen-containing basic compound) (molar ratio) = 2.5 to 300, preferably Is 5.0 to 200, more preferably 7.0 to 150.

  In the positive resist composition of the present invention, a low-molecular acid-decomposable compound, a surfactant, a dissolution-promoting compound for a developer, an antihalation agent, a plasticizer, a photosensitizer, and a surfactant, if necessary. , An adhesion assistant, a crosslinking agent, a photobase generator, and the like can be contained.

The positive resist composition of the present invention has a low molecular acid decomposability, which has a molecular weight of 2000 or less, if necessary, has a group that can be decomposed by the action of an acid, and alkali solubility increases by the action of an acid. Compounds can be included.
For example, described in Proc. SPIE, 2724, 355 (1996), JP-A-8-15865, USP5310619, USP-5372912, J. Photopolym. Sci., Tech., Vol. 10, No. 3, 511 (1997)). Containing an acid-decomposable group, an alicyclic compound such as a cholic acid derivative, a dehydrocholic acid derivative, a deoxycholic acid derivative, a lithocholic acid derivative, a ursocholic acid derivative or an abietic acid derivative, or an acid-decomposable group Aromatic compounds such as naphthalene derivatives 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 reflection 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.

The positive resist composition of the present invention comprises a surfactant, particularly a fluorine-based and / or silicon-based surfactant (a fluorine-based surfactant and a silicon-based surfactant, a surface activity containing both fluorine atoms and silicon atoms). It is preferable to contain any one of these, or two or more.
When the positive resist composition of the present invention contains a fluorine-based and / or silicon-based surfactant, adhesion and development defects are obtained with good sensitivity and resolution when using an exposure light source of 250 nm or less, particularly 220 nm or less. It is possible to provide a resist pattern with less.
As these surfactants, for example, JP-A-62-36663, JP-A-61-22
JP 6746, JP 61-226745, JP 62-170950, JP 63-34540, JP 7-230165, JP 8-62834, JP 9-9 -54432, JP-A-9-5988, JP-A 2002-277862, U.S. Pat. Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330, and 5436098. The surfactants described in the specification, Nos. 5576143, 5294511, and 5824451 can be mentioned, and the following commercially available surfactants can also be used as they are.
Examples of commercially available surfactants that can be used include EFTOP EF301 and EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430 and 431 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189, and R08. (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.), etc. Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

In addition to the known surfactants described above, the surfactant is derived from a fluoroaliphatic compound produced by a telomerization method (also called telomer method) or an oligomerization method (also called oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.
As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. 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) A copolymer of (ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate), C ₈ F ₁
Copolymer of acrylate (or methacrylate) having ₇ groups and (poly (oxyalkylene)) acrylate (or methacrylate), acrylate (or methacrylate) having C ₈ F ₁₇ groups and (poly (oxyethylene)) acrylate ( Or a copolymer of (poly (oxypropylene)) acrylate (or methacrylate), and the like.

  The amount of the surfactant used is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, based on the total amount of the positive resist composition (excluding the solvent).

≪How to use≫
The positive 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 positive resist composition is applied onto a substrate (eg, silicon / silicon dioxide coating) used for manufacturing a precision integrated circuit element by an appropriate application method such as a spinner or a coater.
After coating, exposure is performed through a predetermined mask, baking and development are performed. In this way, a good 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 alkali developer for the positive resist composition include inorganic hydroxides 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 Alkaline aqueous solutions (usually 0.1-10 mass%), such as quaternary ammonium salts, such as 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.
In the following synthesis examples, unless otherwise specified, the ratio and% are mass ratio and mass%.

Synthesis Example (1) Synthesis of Resin (1-1) 2-Norbornyl-2-propyl methacrylate, 3,5-dihydroxy-1-adamantane methacrylate, and cyclohexanelactone acrylate were charged at a ratio of 40/20/40 (molar ratio). Then, it was dissolved in propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether = 60/40 to prepare 450 g of a solution having a solid content concentration of 22%. 1 mol% of a polymerization initiator V-601 manufactured by Wako Pure Chemical Industries, Ltd. was added to this solution, and this was heated to 100 ° 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. The reaction liquid was stirred for 2 hours after completion | finish of dripping. 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 (1-1). did.
^The polymer composition ratio (molar ratio) determined from ¹³ CNMR was a / b / c = 43/19/38. Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 9200, and dispersion degree was 2.1. Moreover, as a result of measuring by the differential scanning calorimeter (DSC), the glass transition point of resin (1-1) was 148 degreeC.

Synthesis Example (2) Synthesis of Resin (2-1) Polymerization was performed in the same manner as in Synthesis Example (1) to obtain the target resin (2-1). ^The polymer composition ratio (molar ratio) determined from ¹³ CNMR was a / b / c = 38/22/40. Moreover, the standard polystyrene conversion weight average molecular weight calculated | required by GPC measurement was 8330, and dispersion degree was 2.1. Moreover, as a result of performing DSC measurement, the glass transition point of resin (2-1) was 131 degreeC.

Synthesis Example (3) Synthesis of Resin (3-1) 2-Adamantyl-2-propyl methacrylate, dihydroxyadamantane methacrylate and norbornane lactone acrylate were charged at a ratio of 40/20/40 (molar ratio), and propylene glycol monomethyl ether acetate / 3-Methoxy-1-butanol was dissolved in 60/40 to prepare 450 g of a solution having a solid content concentration of 22%. 8 mol% of a polymerization initiator V-601 manufactured by Wako Pure Chemical Industries, Ltd. was added to this solution, and this was heated to 120 ° C. over 6 hours in a nitrogen atmosphere, propylene glycol monomethyl ether acetate / 3-methoxy-1-butanol = 60 / It was dripped at 50 g of 40 mixed solutions. The reaction liquid was stirred for 2 hours after completion | finish of dripping. 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 (3-1). did.
^The polymer composition ratio (molar ratio) determined from ¹³ CNMR was a / b / c = 36/23/41. Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 3270, and dispersion degree was 1.5. Moreover, as a result of performing DSC measurement, the glass transition point of resin (3-1) was 119 degreeC.

Synthesis Example (4) Synthesis of Resin (3-2) 2-Adamantyl-2-propyl methacrylate, dihydroxyadamantane methacrylate and norbornane lactone acrylate were charged at a ratio of 40/20/40 (molar ratio), and propylene glycol monomethyl ether acetate / 3-Methoxy-1-butanol was dissolved in 60/40 to prepare 450 g of a solution having a solid content concentration of 22%. To this solution, 6 mol% of Wako Pure Chemical Industries, Ltd. polymerization initiator V-601 was added, and this was heated to 120 ° C. over 6 hours in a nitrogen atmosphere, propylene glycol monomethyl ether acetate / 3-methoxy-1-butanol = 60 / It was dripped at 50 g of 40 mixed solutions. The reaction liquid was stirred for 2 hours after completion | finish of dripping. 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, the precipitated white powder was collected by filtration, and the target resin (3-2) was recovered. did.
^The polymer composition ratio (molar ratio) determined from ¹³ CNMR was a / b / c = 36/23/41. Moreover, the standard polystyrene conversion weight average molecular weight calculated | required by GPC measurement was 4100, and dispersion degree was 1.6. Moreover, as a result of performing DSC measurement, the glass transition point of resin (3-2) was 139 degreeC.

Synthesis Example (5) Synthesis of Resin (4-1) Polymerization was performed in the same manner as in Synthesis Example (1) to obtain the desired resin (4-1). ^The polymer composition ratio (molar ratio) determined from ¹³ CNMR was a / b / c = 37/22/41. Moreover, the standard polystyrene conversion weight average molecular weight calculated | required by GPC measurement was 7760, and dispersion degree was 2.3. Moreover, as a result of performing DSC measurement, the glass transition point of resin (4-1) was 133 degreeC.

Synthesis Example (6) Synthesis of Resin (5-1) Polymerization was performed in the same manner as in Synthesis Example (1) to obtain the target resin (5-1). ^The polymer composition ratio (molar ratio) determined from ¹³ CNMR was a / b / c = 35/32/33. Moreover, the standard polystyrene conversion weight average molecular weight calculated | required by GPC measurement was 9910, and dispersion degree was 2.2. Moreover, as a result of performing DSC measurement, the glass transition point of resin (5-1) was 122 degreeC.

Synthesis Example (7) Synthesis of Resin (6-1) Polymerization was performed in the same manner as in Synthesis Example (4) to obtain the desired resin (6-1).
^The polymer composition ratio (molar ratio) determined from ¹³ CNMR was a / b / c / d = 30/22/39/9. Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 3890, and dispersion degree was 1.6. Moreover, as a result of performing DSC measurement, the glass transition point of resin (6-1) was 134 degreeC.

Synthesis Example (8) Synthesis of Resin (7-1) 2-adamantyl-2-propyl methacrylate, 2-adamantyl-2-propyl acrylate, dihydroxyadamantane methacrylate, norbornane lactone acrylate in 20/20/20/40 (molar ratio) Was dissolved in propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether = 60/40 to prepare 450 g of a solution having a solid content concentration of 22%. 9 mol% of a polymerization initiator V-601 manufactured by Wako Pure Chemical Industries, Ltd. was added to this solution, and this mixture was heated to 80 ° C. over 6 hours in a nitrogen atmosphere and mixed with propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether = 60/40 It was dripped at 50g of solutions. The reaction liquid was stirred for 2 hours after completion | finish of dripping. 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 (7-1). did.
^The polymer composition ratio (molar ratio) determined from ¹³ CNMR was a / b / c / d = 20/20/21/39. Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 7980, and dispersion degree was 2.3. Moreover, as a result of performing DSC measurement, the glass transition point of resin (7-1) was 155 degreeC.

Synthesis Example (9) Synthesis of Resin (7-2) 2-adamantyl-2-propyl methacrylate, 2-adamantyl-2-propyl acrylate, dihydroxyadamantane methacrylate, norbornane lactone acrylate in 20/20/20/40 (molar ratio) Was dissolved in propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether = 60/40 to prepare 450 g of a solution having a solid content concentration of 22%. 5 mol% of Wako Pure Chemical Industries, Ltd. polymerization initiator V-601 was added to this solution, 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. The reaction liquid was stirred for 2 hours after completion | finish of dripping. 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 (7-2). did.
^The polymer composition ratio (molar ratio) determined from ¹³ CNMR was a / b / c / d = 20/20/21/39. Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 9370, and dispersion degree was 2.2. Moreover, as a result of performing DSC measurement, the glass transition point of resin (7-2) was 161 degreeC.

Synthesis Example (10) Synthesis of Resin (8-1) Hydroxyl tetrascrododecanyl carboxylic acid t-butyl ester acrylic acid ester, hydroxy tetrascrododecanyl carboxylic acid methacrylate ester, norbornane lactone acrylate 44/6/50 The mixture was charged at a ratio of (molar ratio) and dissolved in propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether = 60/40 to prepare 450 g of a solution having a solid content concentration of 22%. To this solution, 2.5 mol% of Wako Pure Chemical Industries, Ltd. polymerization initiator V-601 was added, and this was heated at 80 ° C. for 6 hours under a nitrogen atmosphere. Propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether = 60/40 The solution was added dropwise to 50 g of the mixed solution. The reaction liquid was stirred for 2 hours after completion | finish of dripping. 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 (8-1). did.
^The polymer composition ratio (molar ratio) determined from ¹³ CNMR was a / b / c = 45/7/48. Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 10370, and dispersion degree was 2.2. Moreover, as a result of performing DSC measurement, the glass transition point of resin (11-2) was 136 degreeC.

Synthesis Example (11) Synthesis of Resin (9-1) Polymerization was performed in the same manner as in Synthesis Example (1) to obtain the desired resin (9-1). ^The polymer composition ratio (molar ratio) determined from ¹³ CNMR was a / b / c = 45/28/27. Moreover, the standard polystyrene conversion weight average molecular weight calculated | required by GPC measurement was 10180, and dispersion degree was 2.3. Moreover, as a result of performing DSC measurement, the glass transition point of resin (9-1) was 144 degreeC.

Synthesis Example (12) Synthesis of Resin (10-1) Polymerization was performed in the same manner as in Synthesis Example (1) to obtain the target resin (10-1).
^The polymer composition ratio (molar ratio) determined from ¹³ CNMR was a / b / c / d = 35/19/5/41. Moreover, the standard polystyrene conversion weight average molecular weight calculated | required by GPC measurement was 7630, and dispersion degree was 2.0. Moreover, as a result of performing DSC measurement, the glass transition point of resin (10-1) was 139 degreeC.

Synthesis Example (13) Synthesis of Resin (11-1) Polymerization was performed in the same manner as in Synthesis Example (1) to obtain the desired resin (11-1).
^The polymer composition ratio (molar ratio) determined from ¹³ CNMR was a / b / c / d = 37/19/39/5. Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 7560, and dispersion degree was 1.9. Moreover, as a result of performing DSC measurement, the glass transition point of resin (11-1) was 139 degreeC.

Synthesis Example (14) Synthesis of Resin (12-1) Polymerization was performed in the same manner as in Synthesis Example (1) to obtain the target resin (12-1).
^The polymer composition ratio (molar ratio) determined from ¹³ CNMR was a / b / c / d = 39/16/40/5. Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 8670, and dispersion degree was 2.2. Moreover, as a result of performing DSC measurement, the glass transition point of resin (12-1) was 147 degreeC.

Synthesis Example (1) Synthesis of Comparative Resin (R1) 2-Ethyl-2-adamantyl methacrylate and butyrolactone methacrylate were charged at a ratio of 55/45 (molar ratio) and dissolved in methyl ethyl ketone / tetrahydrofuran = 5/5 to obtain a solid concentration of 20 100 mL of a mass% solution was prepared. To this solution, 2 mol% of a polymerization initiator V-65 manufactured by Wako Pure Chemical Industries, Ltd. was added and 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 a resin (R1), which was a white powder crystallized and precipitated in 3 L of a mixed solvent of distilled water / isopropyl alcohol = 1/1, was collected.
The polymer composition ratio (molar ratio) determined from C ¹³ NMR was 46/54. Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 10700.

Synthesis Example (2) Synthesis of Comparative Resin (R2) 2-adamantyl-2-propyl methacrylate, 2-adamantyl-2-propyl acrylate, dihydroxyadamantane methacrylate, norbornane lactone acrylate in 20/20/20/40 (molar ratio) The mixture was charged at a ratio and dissolved in propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether = 60/40 to prepare 450 g of a solution having a solid content concentration of 22% by mass. To this solution, 3.5 mol% of a polymerization initiator V-601 manufactured by Wako Pure Chemical Industries, Ltd. was added, and this was heated to 80 ° C. over 6 hours in a nitrogen atmosphere. Propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether = The solution was added dropwise to 50 g of a 60/40 (mass ratio) mixed solution. The reaction liquid was stirred for 2 hours after completion | finish of dripping. 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 (mass ratio), and the precipitated white powder was collected by filtration to obtain the target resin (R2). Was recovered.
The polymer composition ratio (molar ratio) determined from C ¹³ NMR was 20/20/20/40 corresponding to the order of the above monomers. Moreover, the standard polystyrene conversion weight average molecular weight calculated | required by GPC measurement was 13100, and dispersion degree was 2.1. As a result of DSC measurement, the glass transition point of the resin was 171 ° C.

Examples 1-17 and Comparative Examples 1-4
(Preparation and evaluation of positive resist composition)
1.03 g of resin,
Photoacid generator 0.00035 mol,
Nitrogen-containing basic compound 1.65mg and surfactant 100ppm in total
Were dissolved in the solvent shown in Table 2 so that the solid content was 11% by mass, and then filtered through a 0.1 μm microfilter, and Examples 1 to 17 and Comparative Example 1 were used. -4 positive resist compositions were prepared. In addition, the ratio in the case of using two or more of each component in Table 2 is a mass ratio.

In Table 2, the symbols for the photoacid generator correspond to those exemplified above.
The symbol about a basic compound shows the following.
N-1: 1,5-diazabicyclo [4.3.0] non-5-ene
(DBN)
N-2: Triisodecylamine N-3: Trioctylamine N-4: Triphenylimidazole N-5: Antipyrine N-6: N, N-di-n-butylaniline N-7: Adamantylamine N-8 : Triisooctylamine

The symbol about surfactant shows the following.
W-1: MegaFuck F176 (Dainippon Ink Chemical Co., Ltd.) (Fluorine)
W-2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.) (fluorine and silicone)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.)
W-4: Polyoxyethylene nonylphenyl ether W-5: Troysol S-366 (manufactured by Troy Chemical Co., Ltd.)
Represents.

The symbols for the solvent are as follows.
SL-1: Propylene glycol monomethyl ether acetate SL-2: Ethyl lactate SL-3: Propylene glycol monomethyl ether SL-4: 2-heptanone SL-5: Cyclopentanone SL-6: Cyclohexanone SL-7: 2-Methylcyclohexanone SL-8: Propylene carbonate SL-9: γ-Butyrolactone

[Pattern formation method]
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. Thereafter, each positive resist composition immediately after the preparation was applied by a spin coater and dried at 120 ° C. for 90 seconds to form a 300 nm resist film.
The resist film was exposed with an ArF excimer laser stepper (NA = 0.60 (σ = 0.70) manufactured by ISI) through a mask having a predetermined pattern, and heated on a hot plate at 120 ° C. for 90 seconds immediately after the exposure. Further, the resist film was developed with an aqueous 2.38 mass% tetramethylmonium hydroxide solution at 23 ° C. for 60 seconds, rinsed with pure water for 30 seconds, and then dried to obtain a pattern.

[Line edge roughness (LER)]
The distance from the reference line where the edge should be in a range of 5 μm in the longitudinal direction of the 130 nm isolated trench pattern was measured by 50 points with a length measuring SEM (S-8840 manufactured by Hitachi, Ltd.), and the standard deviation (σ) 3σ (nm) was calculated. A smaller value indicates better performance.

[Defocus latitude (DOF)]
For 130 nm line pattern (line: space = 1: 1), 130 nm isolated line (line: space = 1: 10), and 130 nm isolated trench pattern, the focus variation allowable width is obtained and common focus variation that can be tolerated in all. The width (μm) was determined.
The results are shown in Table 3.

  As is apparent from the results in Table 3, it can be seen that the positive resist composition of the present invention has good performance with low edge roughness and high defocus latitude.

Claims (7)

(A) A repeating unit containing a repeating unit of at least one acrylate derivative and having a repeating unit represented by general formula (IV) and groups represented by general formulas (V-1) to (V-4) A resin containing at least one selected from units and a repeating unit represented by formula (AII) and having increased solubility in an alkali developer by the action of an acid having a glass transition temperature of 70 to 155 ° C.,
(B) a compound that generates an acid upon irradiation with actinic rays or radiation, and
(C) at least one selected from propylene glycol monoalkyl ether carboxylate, alkyl lactate and linear ketone, and selected from cyclopentanone, 3-methylcyclopentanone, cyclohexanone, 2-methylcyclohexanone and 2,6-dimethylcyclohexanone A positive resist composition comprising a mixed solvent containing at least one cyclic ketone .

In the general formula (IV), R ₁ a 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.
Ra ₁ , Rb ₁ , Rc ₁ , Rd ₁ and Re ₁ 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 = 2 to 6.

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 general formula (AII), R _1c represents a hydrogen atom or a methyl group.
R _{2c to} R _4c each independently represents a hydrogen atom or a hydroxyl group. However, at least one of R _{2c to} R _4c represents a hydroxyl group. The resist composition according to claim 1, wherein the cyclic ketone contained in the mixed solvent is at least one selected from cyclopentanone, cyclohexanone, and 2-methylcyclohexanone. The resist composition according to claim 1 or 2 , wherein 10 to 90 mol% of the repeating units constituting the resin (A) are derived from an acrylate monomer. The resist composition according to any one of claims 1 to 3, wherein 50 to 75 mol% of the repeating units constituting the resin (A) are derived from an acrylate monomer. The resist composition according to any one of claims 1 to 4, wherein the compound (B) is a triphenylsulfonium salt. The resist composition according to any one of claims 1 to 4, wherein the compound (B) is a phenacylsulfonium salt. Pattern forming method forming a resist film from the resist composition as described in any one of claims 1 to 6, the resist film, exposure, characterized by development.