JP2007304545A - Positive resist composition and pattern-forming method using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive resist composition that is not only excellent in line edge roughness but also excellent in water following performance, and to provide a pattern-forming method using the same. <P>SOLUTION: A positive resist composition comprises (A) a resin in which its solubility in an alkali developer is increased by action of an acid and which does not contain a silicon atom, (B) a compound that generates an acid upon irradiation with actinic ray or radiation, (C) a silicon atom-containing resin having at least one group selected from groups (X) to (Z), and (D) a solvent, wherein: (X) is an alkali-soluble group; (Y) is a group capable of decomposing by action of an alkali developer to increase the solubility of resin (C) in an alkali developer; and (Z) is a group capable of decomposing by action of an acid to increase the solubility of resin (C) in an alkali developer. The pattern forming method using the same is also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

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 also in a lithography process for other photo applications, and a pattern forming method using the same. It is. In particular, the present invention relates to a positive resist composition for immersion exposure suitable for exposure by an immersion projection exposure apparatus using far ultraviolet light having a wavelength of 300 nm or less as a light source, and a pattern forming method using the same.

Along with the miniaturization of semiconductor elements, the wavelength of the exposure light source has been shortened and the numerical aperture (high NA) of the projection lens has been increased. Currently, an NAF 0.8 light source using an ArF excimer laser having a wavelength of 193 nm is used.
Four exposure machines have been developed. These can be expressed by the following equations as is generally well known.
(Resolving power) = k ₁ · (λ / NA)
(Depth of focus) = ± k ₂ · λ / NA ²
Where λ is the wavelength of the exposure light source, NA is the numerical aperture of the projection lens, and k ₁ and k ₂ are coefficients related to the process.

An exposure machine using a F ₂ excimer laser having a wavelength of 157 nm as a light source has been studied for higher resolution by further shortening the wavelength. Lens materials and resists used in the exposure apparatus for shorter wavelength have been studied. Because the materials used in the process are very limited, it is very difficult to stabilize the manufacturing cost and quality of the apparatus and materials, and the exposure apparatus and resist that have sufficient performance and stability within the required period are not in time. The possibility is coming out.

As a technique for increasing the resolving power in an optical microscope, a so-called immersion method in which a high refractive index liquid (hereinafter also referred to as “immersion liquid”) is filled between a projection lens and a sample is known.
This “immersion effect” means that when λ ₀ is the wavelength of the exposure light in the air, n is the refractive index of the immersion liquid with respect to air, θ is the convergence angle of the light beam, and NA ₀ = sin θ. The above-described resolving power and depth of focus can be expressed by the following equations.
(Resolving power) = k ₁ · (λ ₀ / n) / NA ₀
(Depth of focus) = ± k ₂ · (λ ₀ / n) / NA ₀ ²
That is, the immersion effect is equivalent to using an exposure wavelength having a wavelength of 1 / n. In other words, in the case of a projection optical system with the same NA, the depth of focus can be increased n times by immersion. This is effective for all pattern shapes, and can be combined with a super-resolution technique such as a phase shift method and a modified illumination method which are currently being studied.

Examples of apparatuses in which this effect is applied to the transfer of a fine image pattern of a semiconductor element are introduced in Patent Document 1 (Japanese Patent Laid-Open No. 57-153433), Patent Document 2 (Japanese Patent Laid-Open No. 7-220990), and the like. Yes.
Recent progress in immersion exposure technology is described in Non-Patent Document 1 (SPIE Proc 4688, 11 (2002)), Non-Patent Document 2
(J. Vac. Sci. Tecnol. B 17 (1999)), Non-Patent Document 3 (SPIE Proc 3999, 2 (2000)), Patent Document 3 (International Publication WO 2004-077158 Pamphlet) and the like. In the case of using an ArF excimer laser as a light source, pure water (refractive index of 1.44 at 193 nm) is considered to be most promising as an immersion liquid in terms of handling safety, transmittance at 193 nm, and refractive index. When an F ₂ excimer laser is used as a light source, a solution containing fluorine has been studied from the balance between transmittance and refractive index at 157 nm. However, a sufficient product has not yet been seen in terms of environmental safety and refractive index. It has not been issued. From the degree of immersion effect and the degree of completeness of the resist, the immersion exposure technique is considered to be installed in the ArF exposure machine earliest.

Since the resist for KrF excimer laser (248 nm), an image forming method called chemical amplification has been used as an image forming method for a resist in order to compensate for sensitivity reduction due to light absorption. An example of a positive-type chemical amplification image forming method will be described. When exposed, the acid generator in the exposed area decomposes to generate an acid, and the acid generated in the exposure bake (PEB) is a reaction catalyst. Is used to change an alkali-insoluble group to an alkali-soluble group, and an exposed portion is removed by alkali development.
Although the resist for ArF excimer laser (wavelength 193 nm) using this chemical amplification mechanism is becoming mainstream at present, it is necessary to improve the line edge roughness in the case of immersion exposure.

In addition, when a chemically amplified resist is applied to immersion exposure, the resist layer comes into contact with the immersion liquid at the time of exposure, so that the resist layer is altered and components that adversely affect the immersion liquid are leached from the resist layer. Has been pointed out. Patent Document 4 (International Publication WO 2004-068242 Pamphlet) describes an example in which resist performance changes by immersing a resist for ArF exposure in water before and after exposure, and points to a problem in immersion exposure. .
In the immersion exposure process, when exposure is performed using a scanning immersion exposure machine, the exposure speed decreases unless the immersion liquid moves following the movement of the lens. Concerned about giving. In the case where the immersion liquid is water, it is desirable that the resist film be hydrophobic so that water followability is better.

JP-A-57-153433 JP-A-7-220990 International Publication WO2004-077158 Pamphlet International Publication WO 2004-068242 Pamphlet Proc. SPIE, 2002, Vol. 4688, p. 11 J.Vac.Sci.Tecnol.B 17 (1999) Proc. SPIE, 2000, Vol. 3999, p. 2

  An object of the present invention is to provide a positive resist composition having improved line edge roughness. Also provided are a positive resist composition suitable for immersion exposure, and a pattern formation method using the same, which has a good pattern profile in immersion exposure as well as normal exposure and good followability to immersion liquid. It is to be.

  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 resin having no silicon atom whose solubility in an alkaline developer is increased by the action of an acid;
(B) a compound that generates an acid upon irradiation with an actinic ray or radiation,
(C) a silicon atom-containing resin having at least one group selected from the following groups (X) to (Z), and
(X) an alkali-soluble group (Y) a group that decomposes by the action of an alkali developer and increases the solubility of the resin (C) in the alkali developer; and (Z) a group that decomposes by the action of an acid and decomposes the resin (C) in the alkali developer. A group that increases solubility,
(D) A positive resist composition containing a solvent.

  (2) The positive resist composition as described in (1) above, wherein the resin (A) has a monocyclic or polycyclic alicyclic hydrocarbon structure.

(3) The silicon atom-containing resin (C) is a silicon atom-containing resin that is alkali-soluble and / or has increased solubility in an alkali developer due to the action of an acid, as described in (1) or (2) above A positive resist composition.

  (4) The silicon atom-containing resin (C) is a resin that is alkali-soluble and does not increase the solubility in an alkali developer due to the action of an acid, according to any one of the above (1) to (3) The positive resist composition as described.

  (5) The positive resist composition as described in any one of (1) to (3) above, wherein the silicon atom-containing resin (C) has at least one repeating unit having a lactone group.

  (6) The silicon atom-containing resin (C) is a resin that is insoluble in alkali and has increased solubility in an alkali developer due to the action of an acid, according to any one of the above (1) to (3) The positive resist composition as described.

  (7) The positive resist composition as described in any one of (1) to (6) above, which is exposed to vacuum ultraviolet light having a wavelength of 200 nm or less.

  (8) The positive resist composition as described in any one of (1) to (7) above, wherein the silicon atom-containing resin (C) has a weight average molecular weight of 1,000 to 100,000.

  (9) The positive resist composition as described in any one of (1) to (8) above, wherein the silicon atom-containing resin (C) further has a fluorine atom.

  (10) Any one of (1) to (9) above, wherein the addition amount of the silicon atom-containing resin (C) is 0.1 to 5% by mass relative to the total solid content in the composition. The positive resist composition as described in 1. above.

  (11) The positive resist according to any one of (1) to (10) above, wherein the resin (A) has a repeating unit having an alicyclic hydrocarbon group substituted with a hydroxyl group or a cyano group. Composition.

  (12) A pattern forming method comprising a step of forming a resist film from the resist composition according to any one of (1) to (11), and exposing and developing the resist film.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a positive resist composition suitable for immersion exposure having good line edge roughness and excellent followability to immersion liquid, and a pattern forming method using the same.

Hereinafter, the present invention will be described in detail.
In addition, in the description of the group (atomic group) in this specification, the description which does not describe substitution and non-substitution includes what does not have a substituent and what has a substituent. . For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

(A) A resin having no silicon atom, whose solubility in an alkaline developer is increased by the action of an acid.
The resin used in the resist composition of the present invention is a resin (acid-decomposable resin) that does not have a silicon atom that decomposes by the action of an acid and increases the solubility in an alkaline developer, and is the main chain or side chain of the resin. Or a resin having a group (hereinafter also referred to as “acid-decomposable group”) that decomposes by the action of an acid to generate an alkali-soluble group (hereinafter also referred to as “acid-decomposable group”) in both the main chain and the side chain (hereinafter referred to as “acid-decomposable resin, Resin (A) is also called).

  Specific examples of the resin (A) include poly (hydroxystyrene) derivatives containing a meta, para, or ortho-substituted product as shown below.

Alkali-soluble groups include phenolic hydroxyl groups, carboxylic acid groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, (alkylsulfonyl) (alkylcarbonyl) Imido group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) methylene group A group having
Preferred alkali-soluble groups include carboxylic acid groups, fluorinated alcohol groups (preferably hexafluoroisopropanol), and sulfonic acid groups.
A preferred group as an acid-decomposable group (acid-decomposable group) is a group obtained by substituting the hydrogen atom of these alkali-soluble groups with a group capable of leaving with an acid.
The acid-decomposable group is preferably a cumyl ester group, an enol ester group, an acetal ester group, a tertiary alkyl ester group or the like. More preferably, it is a tertiary alkyl ester group.

The resin (A) preferably has a monocyclic or polycyclic alicyclic hydrocarbon structure.
The resin (A) includes a repeating unit having a partial structure containing an alicyclic hydrocarbon represented by the following general formula (pI) to general formula (pV) and a repeating unit represented by the following general formula (II-AB). A resin containing at least one selected from the group (hereinafter also referred to as an alicyclic hydrocarbon-based acid-decomposable resin) is preferable.

In general formulas (pI) to (pV),
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 is an atom necessary for forming a cycloalkyl group together with a carbon atom. Represents a group.
R _{12 to} R ₁₆ each independently represents a linear or branched alkyl group or cycloalkyl group having 1 to 4 carbon atoms, provided that at least one of R _{12 to} R ₁₄ , or R ₁₅ , Any of R ₁₆ represents a cycloalkyl 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 a cycloalkyl group, provided that at least one of R _{17 to} R ₂₁ is cyclo Represents an alkyl group. Further, either R ₁₉ or R ₂₁ represents a linear or branched alkyl group or cycloalkyl 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 a cycloalkyl group, provided that at least one of R _{22 to} R ₂₅ is cyclo Represents an alkyl group. R ₂₃ and R ₂₄ may be bonded to each other to form a ring.

In the formula (II-AB),
R ₁₁ ′ and R ₁₂ ′ each independently represents a hydrogen atom, a cyano group, a halogen atom or an alkyl group.
Z ′ represents an atomic group for forming an alicyclic structure containing two bonded carbon atoms (C—C).

  The general formula (II-AB) is more preferably the following general formula (II-AB1) or general formula (II-AB2).

In the formula (II-AB1) (II-AB2),
R ₁₃ ′ to R ₁₆ ′ each independently represents a hydrogen atom, a halogen atom, a cyano group, —COOH, —COOR ₅ , a group that decomposes by the action of an acid, —C (═O) —XA′—R. ₁₇ ′ represents an alkyl group or a cycloalkyl group. At least two of R ₁₃ ′ to R ₁₆ ′ may combine to form a ring.
Here, R ₅ represents an alkyl group, a cycloalkyl group, or a group having a lactone structure.
X represents an oxygen atom, a sulfur atom, -NH -, - NHSO ₂ - or an -NHSO ₂ NH-.
A ′ represents a single bond or a divalent linking group.
R ₁₇ ′ represents —COOH, —COOR ₅ , —CN, a hydroxyl group, an alkoxy group, —CO—NH—R ₆ , —CO—NH—SO ₂ —R ₆ or a group having a lactone structure.
R ₆ represents an alkyl group or a cycloalkyl group.
n represents 0 or 1.

In the general formulas (pI) to (pV), the alkyl group in R _{12 to} R ₂₅ represents a linear or branched alkyl group having 1 to 4 carbon atoms.

The cycloalkyl group in R _{11 to} R ₂₅ or the cycloalkyl group formed by Z and the 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 cycloalkyl groups may have a substituent.

  Preferred cycloalkyl groups include adamantyl group, noradamantyl group, decalin residue, tricyclodecanyl group, tetracyclododecanyl group, norbornyl group, cedrol group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, A cyclodecanyl group and a cyclododecanyl group can be mentioned. More preferable examples include an adamantyl group, norbornyl group, cyclohexyl group, cyclopentyl group, tetracyclododecanyl group, and tricyclodecanyl group.

  These alkyl groups and cycloalkyl groups may further have a substituent. Examples of further substituents include an alkyl group (1 to 4 carbon atoms), a halogen atom, a hydroxyl group, and an alkoxy group (1 to 4 carbon atoms). ), A carboxyl group, and an alkoxycarbonyl group (having 2 to 6 carbon atoms). Examples of the substituent that the alkyl group, alkoxy group, alkoxycarbonyl group and the like may further have include a hydroxyl group, a halogen atom, and an alkoxy group.

  The structures represented by the general formulas (pI) to (pV) in the resin can be used for protecting alkali-soluble groups.

As the repeating unit having an alkali-soluble group protected by the structure represented by the general formulas (pI) to (pV), a repeating unit represented by the following general formula (pA) is preferable.

In general formula (pA),
R represents a hydrogen atom, a halogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. A plurality of R may be the same or different.
A represents a single bond, an 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, or a combination of two or more groups. Represents. A single bond is preferable.
Rp ₁ represents any group of the above formulas (pI) to (pV).

  The repeating unit represented by the general formula (pA) is most preferably a repeating unit of 2-alkyl-2-adamantyl (meth) acrylate and dialkyl (1-adamantyl) methyl (meth) acrylate.

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

Examples of the halogen atom in R ₁₁ ′ and R ₁₂ ′ include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom.

Examples of the alkyl group in R ₁₁ ′ and R ₁₂ ′ include a linear or branched alkyl group having 1 to 10 carbon atoms.

The atomic group for forming the alicyclic structure of Z ′ is an atomic group that forms a repeating unit of an alicyclic hydrocarbon which may have a substituent in a resin, and among them, a bridged type alicyclic group. An atomic group for forming a bridged alicyclic structure forming a cyclic hydrocarbon repeating unit is preferred.

Examples of the alicyclic hydrocarbon skeleton to be formed include the same alicyclic hydrocarbon groups as R _{11 to} R _{25 in} the general formulas (pI) to (pV).

The alicyclic hydrocarbon skeleton may have a substituent. Examples of such a substituent include R ₁₃ ′ to R ₁₆ ′ in the general formula (II-AB1) or (II-AB2).

  In the alicyclic hydrocarbon-based acid-decomposable resin according to the present invention, the group decomposed by the action of an acid has a partial structure containing the alicyclic hydrocarbon represented by the general formula (pI) to the general formula (pV). It can be contained in at least one kind of repeating unit among the repeating unit having, the repeating unit represented by formula (II-AB), and the repeating unit of the copolymerization component described later.

Various substituents of R ₁₃ ′ to R ₁₆ ′ in the general formula (II-AB1) or the general formula (II-AB2) are atomic groups for forming an alicyclic structure in the general formula (II-AB). It can also be a substituent of the atomic group Z for forming a bridged alicyclic structure.

  Specific examples of the repeating unit represented by the general formula (II-AB1) or (II-AB2) include the following specific examples, but the present invention is not limited to these specific examples.

  The alicyclic hydrocarbon-based acid-decomposable resin of the present invention preferably has a group having a lactone ring. As the group having a lactone ring, any group having a lactone ring can be used, but a group having a 5- to 7-membered ring lactone structure is preferred. A structure in which another ring structure is condensed to form a structure or a spiro structure is preferable. A group having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16) is more preferable. Further, a group having a lactone structure may be directly bonded to the main chain. Preferred lactone structures are (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), and (LC1-14). Edge roughness and development defects are improved.

The lactone structure moiety may or may not have a substituent (Rb ₂ ). Preferred substituents (Rb ₂ ) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, and a carboxyl group. , Halogen atom, hydroxyl group, cyano group, acid-decomposable group and the like. n ₂ is 0 to
Represents an integer of 4. When n ₂ is 2 or more, a plurality of Rb ₂ may be the same or different, or a plurality of Rb ₂ may be bonded to form a ring.

As the repeating unit having a group having a lactone structure represented by any of the general formulas (LC1-1) to (LC1-16), R _{13 in the} above general formula (II-AB1) or (II-AB2) may be used. Wherein at least one of 'to R ₁₆ ' has a group represented by the general formulas (LC1-1) to (LC1-16) (for example, R _{5 of} -COOR ₅ is represented by the general formulas (LC1-1) to (LC1) -16) or a repeating unit represented by the following general formula (AI).

In general formula (AI),
R _b0 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms. Preferable substituents that the alkyl group for R _b0 may have include a hydroxyl group and a halogen atom.
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 or a methyl group.
A _b is an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, a single bond, an ether group, an ester group, a carbonyl group, a carboxyl group, or a divalent group obtained by combining these. Represents. Preferably a single bond, -Ab ₁ -CO ₂ - is a linking group represented by.
Ab ₁ is a linear, branched alkylene group, monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexyl group, an adamantyl group, or a norbornyl group.
V represents a group represented by any one of the general formulas (LC1-1) to (LC1-16).

The repeating unit having a lactone structure usually has an optical isomer, but any optical isomer may be used. One optical isomer may be used alone, or a plurality of optical isomers may be mixed and used. When one kind of optical isomer is mainly used, the optical purity (ee) thereof is preferably 90 or more, more preferably 95 or more.
Specific examples of the repeating unit having a group having a lactone structure are given below, but the present invention is not limited thereto.

The resin (A) of the present invention preferably contains a repeating unit having an alicyclic hydrocarbon structure substituted with a polar group. This improves the substrate adhesion and developer compatibility. The polar group is preferably a hydroxyl group or a cyano group.
Preferred examples of the alicyclic hydrocarbon structure substituted with a polar group include structures represented by general formulas (VIIa) and (VIIb).

In general formula (VIIa), R _{2c to} R _4c each independently represents a hydrogen atom, a hydroxyl group, or a cyano group. However, at least one of R _{2c to} R _4c represents a hydroxyl group or a cyano group. Preferably, one or two of R _{2c to} R _4c are a hydroxyl group and the remaining is a hydrogen atom, more preferably two of R _{2c to} R _4c are a hydroxyl group and the remaining is a hydrogen atom.

  The group represented by the general formula (VIIa) or (VIIb) is preferably a dihydroxy form or a monohydroxy form, and more preferably a dihydroxy form.

As the repeating unit having a group represented by the general formula (VIIa) or (VIIb), at least one of R ₁₃ ′ to R ₁₆ ′ in the general formula (II-AB1) or (II-AB2) is the above. Those having a group represented by the general formula (VIIa) or (VIIb) (for example, R _{5 in} —COOR ₅ represents a group represented by the general formula (VIIa) or (VIIb)), or the following general formula (AIIa ) Or (AIIb).

In general formulas (AIIa) and (AIIb), R _{1c to} R _4c each independently represent a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.

  Specific examples of the repeating unit having a structure represented by the general formulas (AIIa) and (AIIb) are given below, but the present invention is not limited thereto.

  The alicyclic hydrocarbon-based acid-decomposable resin of the present invention may contain a repeating unit represented by the following general formula (VIII).

In the general formula (VIII), Z ₂ represents —O— or —N (R ₄₁ ) —. R ₄₁ represents a hydrogen atom, a hydroxyl group, an alkyl group, or —OSO ₂ —R ₄₂ . R ₄₂ represents an alkyl group, a cycloalkyl group or a camphor residue. The alkyl group of R ₄₁ and R ₄₂ may be substituted with a halogen atom (preferably a fluorine atom) or the like.

  Examples of the repeating unit represented by the general formula (VIII) include the following specific examples, but the present invention is not limited thereto.

  The alicyclic hydrocarbon-based acid-decomposable resin of the present invention preferably has a repeating unit having an alkali-soluble group, and more preferably has a repeating unit having a carboxyl group. By containing this, the resolution in contact hole applications increases. The repeating unit having a carboxyl group includes a repeating unit in which a carboxyl group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or a carboxyl group in the main chain of the resin through a linking group. Any of the bonded repeating units is preferable, and the linking group may have a monocyclic or polycyclic hydrocarbon structure. Most preferred are acrylic acid and methacrylic acid.

  The alicyclic hydrocarbon-based acid-decomposable resin of the present invention may further have a repeating unit having 1 to 3 groups represented by the general formula (F1). This improves line edge roughness performance.

In general formula (F1),
R _{50 to} R ₅₅ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{50 to} R ₅₅ represents a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom.
Rx represents a hydrogen atom or an organic group (preferably an acid-decomposable protecting group, an alkyl group, a cycloalkyl group, an acyl group, or an alkoxycarbonyl group).

The alkyl group of R _{50 to} R ₅₅ may be substituted with a halogen atom such as a fluorine atom, a cyano group, etc., preferably an alkyl group having 1 to 3 carbon atoms, such as a methyl group or a trifluoromethyl group. be able to. R _{50 to} R ₅₅ are preferably all fluorine atoms.

Examples of the organic group represented by Rx include an acid-decomposable protective group and an optionally substituted alkyl group, cycloalkyl group, acyl group, alkylcarbonyl group, alkoxycarbonyl group, alkoxycarbonylmethyl group, alkoxymethyl group. , 1-alkoxyethyl group is preferable.

  The repeating unit having the general formula (F1) is preferably a repeating unit represented by the following general formula (F2).

In the formula, Rx represents a hydrogen atom, a halogen atom, or an alkyl group. Preferable substituents that the alkyl group of Rx may have include a hydroxyl group and a halogen atom.
Fa represents a single bond or a linear or branched alkylene group, preferably a single bond.
Fb represents a monocyclic or polycyclic hydrocarbon group.
Fc represents a single bond or a linear or branched alkylene group (preferably a single bond or a methylene group).
F ₁ represents a group represented by the general formula (F1).
p ₁ is an integer of 1 to 3.
The cyclic hydrocarbon group for Fb is preferably a cyclopentyl group, a cyclohexyl group, or a norbornyl group.

  Hereinafter, although the specific example of the repeating unit which has a structure of general formula (F1) is shown, this invention is not limited to this.

  In addition to the above repeating structural units, the alicyclic hydrocarbon-based acid-decomposable resin of the present invention has a dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and resolving power that is a general necessary characteristic of a resist. Various repeating structural units can be contained for the purpose of adjusting heat resistance, sensitivity, and the like.

  Examples of such a repeating structural unit include, but are not limited to, repeating structural units corresponding to the following monomers.

  As a result, performance required for the alicyclic hydrocarbon-based acid-decomposable resin, in particular, (1) solubility in coating solvents, (2) film-forming properties (glass transition point), (3) alkali developability, (4 Fine adjustments such as :) film slippage (selection of hydrophilicity / hydrophobicity, alkali-soluble group), (5) adhesion of unexposed part to substrate, (6) dry etching resistance, etc. are possible.

  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.

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

  In alicyclic hydrocarbon-based acid-decomposable resins, the molar ratio of each repeating structural unit is the resist's dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and resolution that is a general required performance of resists. In order to adjust heat resistance, sensitivity, etc., it is set appropriately.

Preferred embodiments of the alicyclic hydrocarbon-based acid-decomposable resin of the present invention include the following.
(1) What contains the repeating unit which has a partial structure containing the alicyclic hydrocarbon represented by said general formula (pI)-(pV) (side chain type).
Preferably those containing (meth) acrylate repeating units having a structure of (pI) to (pV).
(2) Containing a repeating unit represented by the general formula (II-AB) (main chain type).
However, in (2), for example, the following can be further mentioned.
(3) Those having a repeating unit represented by formula (II-AB), a maleic anhydride derivative and a (meth) acrylate structure (hybrid type).

  In the alicyclic hydrocarbon-based acid-decomposable resin, the content of the repeating unit having an acid-decomposable group is preferably 10 to 60 mol%, more preferably 20 to 50 mol%, still more preferably 25 in all repeating structural units. -40 mol%.

  In the alicyclic hydrocarbon-based acid-decomposable resin, the content of the repeating unit having a partial structure containing the alicyclic hydrocarbon represented by the general formulas (pI) to (pV) is 25 to 70 in all the repeating structural units. The mol% is preferable, more preferably 35 to 65 mol%, and still more preferably 40 to 60 mol%.

  In the alicyclic hydrocarbon-based acid-decomposable resin, the content of the repeating unit represented by the general formula (II-AB) is preferably 10 to 60 mol%, more preferably 15 to 55 mol% in all repeating structural units. More preferably, it is 20-50 mol%.

  In the resin (A), the content of the repeating unit having an acid-decomposable group is preferably 5 to 50 mol%, more preferably 10 to 40 mol%, still more preferably 15 to 35 mol% in all repeating structural units. is there.

  In the resin (A), the content of the repeating unit having a monocyclic or polycyclic alicyclic hydrocarbon structure is preferably from 25 to 70 mol%, more preferably from 35 to 65 mol%, further preferably from all repeating structural units. Is 40 to 60 mol%.

  In the resin (A), the content of the repeating unit having an alicyclic hydrocarbon group substituted with a polar group is preferably from 5 to 50 mol%, more preferably from 5 to 40 mol%, even more preferably from all repeating structural units. Is 10-30 mol%.

  In addition, the content of the repeating structural unit based on the monomer of the further copolymer component in the resin can also be appropriately set according to the performance of the desired resist. ) To 99 p% with respect to the total number of moles of the repeating structural unit having a partial structure containing an alicyclic hydrocarbon represented by (pV) and the repeating unit represented by the general formula (II-AB). The following is preferable, More preferably, it is 90 mol% or less, More preferably, it is 80 mol% or less.

When the composition of the present invention is for ArF exposure, the resin (A) preferably has no aromatic group from the viewpoint of transparency to ArF light.
The alicyclic hydrocarbon-based acid-decomposable resin used in the present invention is preferably one in which all of the repeating units are composed of (meth) acrylate-based repeating units. In this case, all of the repeating units may be methacrylate repeating units, all of the repeating units may be acrylate repeating units, or a mixture of methacrylate repeating units / acrylate repeating units, but all of the acrylate repeating units may be used. It is preferable that it is 50 mol% or less of a repeating unit. More preferably, the (meth) acrylate-based repeating unit having a partial structure containing an alicyclic hydrocarbon represented by the general formulas (pI) to (pV) is contained in an amount of 25 to 50 mol%, and the (meth) acrylate-based repeating unit having a lactone structure. A terpolymer having 5 to 30 mol% of a (meth) acrylate-based repeating unit having an alicyclic hydrocarbon structure substituted with 25 to 50 mol% of a polar group, or a carboxyl group, or a general formula (F1) It is a quaternary copolymer containing 5 to 20 mol% of a (meth) acrylate-based repeating unit containing a structure represented by:

  The resin (A) used in the present invention is preferably in the range of a weight average molecular weight of 1500 to 100,000, more preferably in the range of 2000 to 70000, and particularly preferably in the range of 3000 to 50000.

The resin (A) used in the present invention can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and the polymerization is performed by heating, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, the polymerization is performed using the same solvent as that used in the resist composition of the present invention. Thereby, the generation of particles during storage can be suppressed.
The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. 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 5 to 50% by mass, preferably 10 to 30% by mass.
The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 50 to 100 ° C.

  In the present invention, the addition amount of the resin (A) in the positive resist composition is 50 to 99.7%, preferably 70 to 99.5%, based on the total solid content. Here, the total solid content refers to all components excluding the solvent (D) in the components constituting the resist composition. In addition to the resin in the present invention, other resins can be used as necessary. In the composition of the present invention, the preferred range of use of the other resin is 70 parts by mass or less, particularly preferably 50 parts by mass or less, per 100 parts by mass of the resin (A) in the present invention.

(B) Compound that generates acid upon irradiation with actinic ray or radiation The positive resist composition of the present invention contains a compound that generates acid upon irradiation with actinic ray or radiation.
Examples of such an acid generator include a photoinitiator for photocationic polymerization, a photoinitiator for photoradical polymerization, a photodecolorant for dyes, a photochromic agent, or an actinic ray or radiation used for a microresist. A known compound that generates an acid by irradiation and a mixture thereof can be appropriately selected and used.

  Examples thereof include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonates.

  Further, a group that generates an acid upon irradiation with these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, 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, The compounds described in JP-A 63-146029 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.

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

In the general formula (ZI),
R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
X ⁻ represents a non-nucleophilic anion, preferably sulfonate anion, carboxylate anion, bis (alkylsulfonyl) amide anion, tris (alkylsulfonyl) methide anion, BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ^{− and the} like. Preferably, it is an organic anion containing a carbon atom.

  Preferable organic anions include organic anions represented by the following formula.

In the formula, Rc ₁ represents an organic group.
Examples of the organic group in Rc ₁ include those having _{1 to} 30 carbon atoms, and preferably an alkyl group, a cycloalkyl group, an aryl group, or a plurality thereof, which may be substituted, is a single bond, —O—, —CO. _{2 -, - S -, -} SO 3 -, - SO 2 N (Rd 1) - it can be exemplified linked group a linking group such as. Rd ₁ represents a hydrogen atom or an alkyl group.
Rc ₃ , Rc ₄ and Rc ₅ represent an organic group. Preferred examples of the organic group for Rc ₃ , Rc ₄ , and Rc ₅ include the same organic groups as those for Rc _1, and a perfluoroalkyl group having 1 to 4 carbon atoms is most preferred.
Rc ₃ and Rc ₄ may combine to form a ring.
Examples of the group formed by combining Rc ₃ and Rc ₄ include an alkylene group and an arylene group. Preferably, it is a C2-C4 perfluoroalkylene group.
The organic group of Rc ₁ and Rc _{3 to} Rc ₅ is most preferably an alkyl group substituted at the 1-position with a fluorine atom or a fluoroalkyl group, or a phenyl group substituted with a fluorine atom or a fluoroalkyl group. By having a fluorine atom or a fluoroalkyl group, the acidity of the acid generated by light irradiation is increased and the sensitivity is improved. Further, when Rc ₃ and Rc ₄ are combined to form a ring, the acidity of the acid generated by light irradiation is increased, and the sensitivity is improved.

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

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

  More preferable (ZI) components include compounds (ZI-1), (ZI-2), and (ZI-3) described below.

The compound (ZI-1) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (ZI), arylsulfonium compound, i.e., a compound having arylsulfonium as a cation.
In the arylsulfonium compound, all of R _{201 to} R ₂₀₃ may be an aryl group, or R ₂₀₁
Some of to R ₂₀₃ is an aryl group with the remaining being an alkyl group or a cycloalkyl group.
Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, aryldialkylsulfonium compounds, diarylcycloalkylsulfonium compounds, and aryldicycloalkylsulfonium compounds.
The aryl group of the arylsulfonium compound is preferably an aryl group such as a phenyl group or a naphthyl group, or a heteroaryl group such as an indole residue or a pyrrole residue, more preferably a phenyl group or an indole residue. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.
The alkyl group that the arylsulfonium compound has as necessary is preferably a linear or branched alkyl group having 1 to 15 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, sec- Examples thereof include a butyl group and a t-butyl group.
The cycloalkyl group that the arylsulfonium compound has as necessary is preferably a cycloalkyl group having 3 to 15 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.
Aryl group, alkyl group of R ₂₀₁ to R _203, cycloalkyl group, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (for example, 6 to 14 carbon atoms) , An alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio group may be substituted. Preferred substituents are straight chain, branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, straight chain, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, and most preferably They are a C1-C4 alkyl group and a C1-C4 alkoxy group. The substituent may be substituted with any one of the three R _{201 to} R ₂₀₃ , or may be substituted with all three. When R _{201 to} R ₂₀₃ are an aryl group, the substituent is preferably substituted at the p-position of the aryl group.

Next, the compound (ZI-2) will be described.
Compound (ZI-2) is a compound in the case where R _{201 to} R ₂₀₃ in formula (ZI) each independently represents an organic group containing no aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.
The organic group having no aromatic ring as R ₂₀₁ to R ₂₀₃ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.
R _{201 to} R ₂₀₃ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear, branched, cyclic 2-oxoalkyl group, or an alkoxycarbonylmethyl group, most preferably Is a linear, branched 2-oxoalkyl group.

The alkyl group as R ₂₀₁ to R ₂₀₃ may be either straight-chain, branched, preferably a straight-chain or branched alkyl group (e.g., methyl group, an ethyl group having 1 to 10 carbon atoms, a propyl group Butyl group, pentyl group). The alkyl group as R ₂₀₁ to R ₂₀₃ may be linear, branched 2-oxoalkyl group is preferably an alkoxycarbonyl methyl group.
The cycloalkyl group as R ₂₀₁ to R ₂₀₃ is preferably, and a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, norbornyl). The cycloalkyl group as R ₂₀₁ to R ₂₀₃ is preferably a cyclic 2-oxoalkyl group.
The 2-oxoalkyl group as R _{201 to} R ₂₀₃ may be linear, branched or cyclic, and preferably a group having> C═O at the 2-position of the above alkyl group or cycloalkyl group Can be mentioned.
The alkoxy group in the alkoxycarbonylmethyl group as R ₂₀₁ to R _203, preferably may be mentioned alkoxy groups having 1 to 5 carbon atoms (a methoxy group, an ethoxy group, a propoxy group, a butoxy group, pentoxyl group).
R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (eg, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

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

In general formula (ZI-3),
R _{1c to} R _5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, or a halogen atom.
R _6c and R _7c each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group.
Rx and Ry each independently represents an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group.
Any two or more of R _1c to R _7c, and R _x and R _y may be bonded to each other to form a ring structure, the ring structure may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond May be included. Examples of the group formed by combining any two or more of R _{1c to} R _7c and R _x and R _y include a butylene group and a pentylene group.
X ⁻ represents a non-nucleophilic anion, and examples thereof include the same non-nucleophilic anion as X ^{− in} formula (ZI).

The alkyl group as R _{1c to} R _7c may be either linear or branched, for example, a linear or branched alkyl group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. And a linear or branched alkyl group (for example, a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched butyl group, a linear or branched pentyl group).
Examples of the cycloalkyl group as R _{1c to} R _7c include a cycloalkyl group having 3 to 8 carbon atoms (for example, a cyclopentyl group and a cyclohexyl group).
The alkoxy group as R _{1c to} R _{5c may} be linear, branched or cyclic, for example, an alkoxy group having 1 to 10 carbon atoms, preferably a linear or branched alkoxy group having 1 to 5 carbon atoms. (For example, methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group), C3-C8 cyclic alkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group) ).
Preferably, any one of R _{1c to} R _5c is a linear or branched alkyl group, a cycloalkyl group, or a linear, branched or cyclic alkoxy group, and more preferably the sum of the carbon number of R _{1c to} R _5c is 2 ~ 15. Thereby, solvent solubility improves more and generation | occurrence | production of a particle is suppressed at the time of a preservation | save.

_Examples of the alkyl group as R _x and R _y include the same alkyl groups as R _{1c to} R _7c . The alkyl group as R _x and R _y is preferably a linear or branched 2-oxoalkyl group or an alkoxycarbonylmethyl group.
The cycloalkyl group as R _x and R _y may be the same as the cycloalkyl group as R _1c to R _7c. The cycloalkyl group as R _x and R _y is preferably a cyclic 2-oxoalkyl group.
Examples of the linear, branched or cyclic 2-oxoalkyl group include a group having> C═O at the 2-position of the alkyl group or cycloalkyl group as R _{1c to} R _7c .
Examples of the alkoxy group in the alkoxycarbonylmethyl group include the same alkoxy groups as R _{1c to} R _5c .
R _x and R _y are preferably an alkyl group having 4 or more carbon atoms, more preferably 6 or more, and still more preferably 8 or more.

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

  Among the compounds that decompose upon irradiation with actinic rays or radiation to generate acids, compounds represented by the following general formulas (ZIV), (ZV), and (ZVI) can be further exemplified.

In general formulas (ZIV) to (ZVI),
Ar ₃ and Ar ₄ each independently represents an aryl group.
R ₂₀₆ represents an alkyl group, a cycloalkyl group or an aryl group.
R ₂₀₇ and R ₂₀₈ each independently represents an alkyl group, a cycloalkyl group or an aryl group, or an electron-withdrawing group. R ₂₀₇ is preferably an aryl group. R ₂₀₈ is preferably an electron-withdrawing group, more preferably a cyano group or a fluoroalkyl group.
A represents an alkylene group, an alkenylene group or an arylene group.

  Of the compounds that decompose upon irradiation with actinic rays or radiation to generate an acid, compounds represented by general formulas (ZI) to (ZIII) are more preferable.

  Among the compounds that generate an acid upon irradiation with actinic rays or radiation, examples of particularly preferable compounds are listed below, but the present invention is not limited thereto.

An acid generator can be used individually by 1 type or in combination of 2 or more types. When two or more types are used in combination, it is preferable to combine two types of compounds that generate two types of organic acids that differ in the total number of atoms excluding hydrogen atoms by two or more.
The content of the acid generator in the composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and still more preferably 1 to 7% by mass, based on the total solid content of the resist composition. %.

(C) Silicon atom-containing resin The positive resist composition of the present invention has a silicon atom-containing resin (referred to as “resin (C)”) having at least one group selected from the following groups (X) to (Z). Contain).
(X) an alkali-soluble group,
(Y) a group that decomposes by the action of an alkali developer and increases the solubility of the resin (C) in the alkali developer (hereinafter sometimes referred to as “alkali hydrolyzable group”); and (Z) a group that decomposes by the action of an acid. And a group that increases the solubility of the resin (C) in an alkaline developer (hereinafter sometimes referred to as “acid-decomposable group”).

  (X) Alkali-soluble group means that the solubility of the silicon atom-containing resin (C) in a 2.38% tetramethylammonium hydroxide aqueous solution at 23 ° C. is increased as compared with the case where (X) the alkali-soluble group is not included. The acid group is preferably an acid group having a pKa of 0.0 to 15.0, more preferably 3.0 to 12.0.

(X) Alkali-soluble groups include phenolic hydroxyl groups, carboxylic acid groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, (alkylsulfonyl) ( Alkylcarbonyl) imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) ) A group having a methylene group is a preferred example.
More preferable (X) alkali-soluble groups include carboxylic acid groups, fluorinated alcohol groups (preferably hexafluoroisopropanol), and sulfonylimide groups.

The repeating unit having an alkali-soluble group (X) includes a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or a main group of the resin via a linking group. It is preferable to use a repeating unit in which an alkali-soluble group is bonded to the chain, and further introduce a polymerization initiator or chain transfer agent having an alkali-soluble group at the end of the polymer chain at the time of polymerization.
As for content of the repeating unit which has alkali-soluble group (X), 1-50 mol% is preferable with respect to all the repeating units in resin (C), More preferably, it is 3-35 mol%, More preferably, it is 5-20 mol%. is there.

  Specific examples of the repeating unit having an alkali-soluble group (X) are shown below, but the present invention is not limited thereto.

  (Y) A group (alkali hydrolyzable group) which decomposes by the action of an alkali developer and increases the solubility of the resin (C) in the alkali developer (an alkali hydrolyzable group) refers to the above-mentioned (X ) Refers to a group that is converted to an alkali-soluble group.

  Examples of the (Y) alkali hydrolyzable group include a lactone group, an ester group, a sulfonamide group, an acid anhydride, and an acid imide group. More preferred examples include a lactone group, a sulfonamide group, and an acid imide. It is a group.

As the repeating unit having an alkali hydrolyzable group, a repeating unit in which an alkali hydrolyzable group is bonded to the main chain of the resin via a linking group, such as a repeating unit by an acrylic ester or a methacrylic ester, or It is preferable to use a polymerization initiator or a chain transfer agent having an alkali hydrolyzable group (Y) introduced at the terminal of the resin (C) during polymerization.
The content of the repeating unit having an alkali hydrolyzable group (Y) is preferably from 1 to 40 mol%, more preferably from 3 to 30 mol%, still more preferably from 5 to 15 mol, based on all repeating units in the resin (C). %.

  (Y) Particularly preferred as the alkali hydrolyzable group is a lactone group. Although any group having a lactone ring can be used as the lactone group, it is preferably a group having a 5- to 7-membered ring lactone structure, and forms a bicyclo structure or a spiro structure in the 5- to 7-membered ring lactone structure. The other ring structure is preferably condensed. A group having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16) is more preferable. Further, a group having a lactone structure may be directly bonded to the main chain. Preferred lactone structures are (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), and (LC1-14). By using these lactone structures, Line edge roughness and development defects are improved.

The lactone structure moiety may or may not have a substituent (Rb ₂ ). Preferred substituents (Rb ₂ ) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, and a carboxyl group. , Halogen atom, hydroxyl group, cyano group, acid-decomposable group and the like. n ₂ is 0 to
Represents an integer of 4. When n ₂ is 2 or more, a plurality of Rb ₂ may be the same or different, and a plurality of Rb ₂ may be bonded to form a ring.

  As the repeating unit having a group having a lactone structure represented by any of the general formulas (LC1-1) to (LC1-16), the following general formula (Lc-AB1), general formula (Lc-AB2), or The repeating unit represented by general formula (LcI) can be mentioned.

In the general formulas (Lc-AB1) and (Lc-AB2),
R ₁₃ ′ to R ₁₆ ′ each independently represent —COOR ₅ or —C (═O) —XA′—R ₁₇ ′.
Here, R ₅ represents a group having a lactone structure of any one of the general formulas (LC1-1) to (LC1-16).
X represents an oxygen atom, a sulfur atom, -NH -, - NHSO ₂ - or an -NHSO ₂ NH-.
A ′ represents a single bond or a divalent linking group.
R ₁₇ ′ represents —COOR ₅ or a group having a lactone structure of any one of the general formulas (LC1-1) to (LC1-16).
In the general formula (LcI),
Rb ₀ represents a hydrogen atom, a halogen atom or an alkyl group. Preferable substituents that the alkyl group of Rb ₀ may have include a hydroxyl group and a halogen atom.
Examples of the halogen atom for Rb ₀ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Rb ₀ is preferably a hydrogen atom or a methyl group.
Ab represents a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, a carboxyl group, or a divalent group obtained by combining these. . Preferably a single bond, -Ab ₁ -CO ₂ - is a linking group represented by. Ab ₁ is a linear, branched alkylene group, monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexyl group, an adamantyl group, or a norbornyl group.
V represents a group represented by any one of the general formulas (LC1-1) to (LC1-16).

  The repeating unit having a lactone ring is preferably a repeating unit represented by the above general formula (LcI).

  The repeating unit having a lactone structure usually has an optical isomer, but any optical isomer may be used. One optical isomer may be used alone, or a plurality of optical isomers may be mixed and used. When one kind of optical isomer is mainly used, the optical purity (ee) thereof is preferably 90 or more, more preferably 95 or more.

  Specific examples of the repeating unit having a group having a lactone structure are given below, but the present invention is not limited thereto.

  (Z) A group (acid-decomposable group) that decomposes by the action of an acid and increases the solubility of the resin (C) in an alkaline developer (acid-decomposable group) is a post-exposure heating step (usually included in a general resist pattern formation process (Exposure Bake = PEB) is a group that undergoes a decomposition reaction using the acid generated in the exposed area as a catalyst and is converted to the above-mentioned (X) alkali-soluble group.

  Examples of the (Z) acid-decomposable group include the same acid-decomposable groups as mentioned in the above-mentioned resin (A).

  The content of the repeating unit having an acid-decomposable group (Z) is preferably from 1 to 80 mol%, more preferably from 10 to 80 mol%, still more preferably from 20 to 60 mol%, based on all repeating units in the resin (C). It is.

  When the silicon atom-containing resin (C) has either (X) an alkali-soluble group or (Y) an alkali-hydrolyzable group (or both), the (Z) acid-decomposable group may not be included. preferable.

  Further, when the silicon atom-containing resin (C) has (Z) an acid-decomposable group, it is preferable that neither (X) an alkali-soluble group nor (Y) an alkali-hydrolyzable group is contained.

The silicon atom-containing resin (C) is a resin having at least one group selected from the group of (X) to (Z) described above and having increased solubility in an alkali developer due to alkali solubility and / or acid action. It may be.
The alkali-soluble in the resin (C) means that the resin (C) is soluble in an alkali developer as described later (usually an alkaline aqueous solution of pH 10.0 to 15.0, 23 ° C.).
When the resin (C) is an alkali-soluble resin, the resin (C) has an alkali-soluble group (X) and / or a group (Y) that is solubilized by hydrolysis with an alkali developer. Specific examples include the aforementioned alkali-soluble groups and alkali-hydrolyzable groups.
The acid decomposability in the resin (C) means that the solubility in an alkali developer is increased by the action of an acid.
When the resin (C) is a resin whose solubility in an alkaline developer is increased by the action of an acid, the resin (C) is a group (Z) (acid-decomposable group) that is decomposed by the action of an acid to generate an alkali-soluble group. That is, it has a group in which an alkali-soluble group is protected. Specifically, what has the group similar to the acid-decomposable group in resin (A) is mentioned.
When the resin (C) is alkali-soluble, it is preferably a resin that is alkali-soluble and does not increase the solubility in an alkali developer due to the action of an acid.
In the case where the resin (C) is a resin whose solubility in an alkaline developer is increased by the action of an acid, the solubility in an alkali developer is increased by the action of an acid, and the unexposed portion is preferably alkali-insoluble.

  Resin (C) contains a silicon atom, which is bonded together in the above repeating unit containing (X) alkali-soluble group, (Y) alkali-hydrolyzable group, and (Z) acid-decomposable group. It may be contained, or may be contained in a repeating unit different from the repeating unit containing the groups (X) to (Z).

  The group having a silicon atom contained in the resin (C) is not particularly limited as long as it is a group containing at least one silicon atom, but silyl ether, siloxane, alkylsilane and the like are preferable, and in particular, cyclic siloxane or the following general formula The group represented by (I) is more preferable.

In general formula (I):
A ₁ represents a single bond, an alkylene group, or — (CH ₂ O) n—.
R ₄ each independently represents a hydrogen atom, an alkyl group or an alkoxy group.
R ₅ each independently represents a hydrogen atom, an alkyl group or an alkoxy group. Two R _{5 's} may be linked to each other to form a ring structure.
n represents the integer of 0-5 each independently.

Specific examples of the cyclic siloxane that is preferably contained in the resin (C) are shown below.
The present invention is not limited to these.

In the above formula,
R represents an alkyl group.
A ₁ represents a single bond, an alkylene group, or — (CH ₂ O) n—.

  Preferred specific examples of the silicon-containing group represented by the general formula (I) are shown below, but the present invention is not limited to these.

  The resin (C) preferably has a silicon atom in the form of any one of the repeating units represented by the following general formulas (C1) and (C2).

In the general formulas (C1) and (C2),
X ₁₁ represents an oxygen atom or —N (R ₁₃ ) —. R ₁₃ represents a hydrogen atom, an alkyl group, or a cycloalkyl group. The alkyl group may be linear or branched, and may have a substituent such as a halogen atom.
R ₁₁ represents a hydrogen atom, a halogen atom, an alkyl group, or a cycloalkyl group. The alkyl group may be linear or branched, and may have a substituent such as a halogen atom.
R ₁₂ and R ₂₁ each independently represents an organic group having at least one silicon atom. Specifically, it is preferable to use the silicon-containing group described above.
The alkyl group represented by R ₁₁ and R ₁₃ preferably has 1 to 5 carbon atoms, and examples thereof include a methyl group, an ethyl group, and a t-butyl group. The cycloalkyl group represented by R ₁₁ and R ₁₃ preferably has 3 to 10 carbon atoms, and examples thereof include a cyclohexyl group and a cyclooctyl group.

  Specific examples of the repeating unit having silicon in the resin (C) are shown below, but are not limited thereto.

  The silicon atom-containing resin (C) contained in the positive resist composition of the present invention may further contain a fluorine atom.

When the silicon atom-containing resin (C) contains a fluorine atom, the fluorine atom is preferably contained as a group selected from the following groups (Fa) to (Fc).
(Fa) an alkyl group having 1 to 4 carbon atoms having a fluorine atom,
(Fb) a cycloalkyl group having a fluorine atom and (Fc) an aryl group having a fluorine atom.

(F-a) The C1-C4 alkyl group which has a fluorine atom is a C1-C4 linear or branched alkyl group which the at least 1 fluorine atom substituted, and also has another substituent. You may do it.
(Fb) The cycloalkyl group having a fluorine atom is a monocyclic or polycyclic cycloalkyl group substituted with at least one fluorine atom, and may further have another substituent.
(Fc) The aryl group having a fluorine atom includes an aryl group such as a phenyl group or a naphthyl group substituted with at least one fluorine atom, and may further have another substituent.

  When the silicon atom-containing resin (C) contains a fluorine atom, the fluorine atom may be in the main chain or the side chain of the resin, but is preferably in the side chain.

  When the silicon-containing resin (C) contains a fluorine atom, (X) an alkali-soluble group, (Y) an alkali-hydrolyzable group, and (Z) an acid-decomposable group contained in the resin (C) Can be included. Specifically, a fluorinated alcohol group such as a hexafluoroisopropanol group can be contained as the (X) alkali-soluble group.

When the silicon-containing resin (C) contains a fluorine atom, as described above, it is included together in a repeating unit containing (X) an alkali-soluble group, (Y) an alkali-hydrolyzable group, and (Z) an acid-decomposable group. Or may be contained in a repeating unit different from the repeating unit containing the groups (X) to (Z).

  Specifically, it is preferable that a fluorine atom is contained in any of the repeating units represented by the following general formulas (C3) and (C4).

In general formulas (C3) and (C4),
X ₃₁ represents an oxygen atom or —N (R ₃₃ ) —. R ₃₃ represents a hydrogen atom, an alkyl group, or a cycloalkyl group. The alkyl group may be linear or branched, and may have a substituent such as a halogen atom.
R ₃₁ represents a hydrogen atom, a halogen atom, an alkyl group, or a cycloalkyl group. The alkyl group may be linear or branched, and may have a substituent such as a halogen atom.
R ₃₂ and R ₄₁ represent an organic group having at least one fluorine atom.
The alkyl group represented by R ₃₁ and R ₃₃ preferably has 1 to 5 carbon atoms, and examples thereof include a methyl group, an ethyl group, and a t-butyl group. The cycloalkyl group represented by R ₃₁ and R ₃₃ preferably has 3 to 10 carbon atoms, and examples thereof include a cyclohexyl group and a cyclooctyl group.

  When the silicon-containing resin (C) has a fluorine atom, specific examples of the repeating unit having a fluorine atom are listed below, but the invention is not limited thereto.

  Although the specific example of resin (C) is given to the following, it is not limited to these.

The resin (C) is preferably a resin selected from the following (C-1) to (C-12). More preferred is a resin selected from (C-1) to (C-4) and (C-8) to (C-13).
(C-1) A resin having a repeating unit (a) having a group having a silicon atom and a repeating unit (x) having an alkali-soluble group (X). More preferably, a copolymer resin of the repeating unit (a) and the repeating unit (x).
(C-2) a repeating unit (a) having a group having a silicon atom, and a repeating unit (y) having a group (Y) that decomposes by the action of an alkali developer and increases the solubility in the alkali developer. Having a resin. More preferably, a copolymer resin of the repeating unit (a) and the repeating unit (y).
(C-3) A resin having a repeating unit (a) having a group having a silicon atom and a repeating unit (z) having a group (Z) that is decomposed by the action of an acid. More preferably, a copolymer resin of the repeating unit (a) and the repeating unit (z).
(C-4) The repeating unit (a) having a group having a silicon atom, the repeating unit (x) having an alkali-soluble group (X), and the solubility in an alkali developer by being decomposed by the action of an alkali developer. And a repeating unit (y) having a group (Y) that increases. More preferably, a copolymer resin of the repeating unit (a), the repeating unit (x), and the repeating unit (y).
(C-5) a repeating unit (a) having a group having a silicon atom, a repeating unit (x) having an alkali-soluble group (X), and a repeating unit (z) having a group (Z) decomposed by the action of an acid ). More preferably, a copolymer resin of the repeating unit (a), the repeating unit (x) and the repeating unit (z).
(C-6) a repeating unit (a) having a group having a silicon atom, a repeating unit (y) having a group (Y) which decomposes by the action of an alkali developer and increases the solubility in the alkali developer, And a resin having a repeating unit (z) having a group (Z) that decomposes by the action of an acid. More preferably, a copolymer resin of the repeating unit (a), the repeating unit (y), and the repeating unit (z).
(C-7) The repeating unit (a) having a group having a silicon atom, the repeating unit (x) having an alkali-soluble group (X), and the solubility in an alkali developer by being decomposed by the action of an alkali developer. A resin having a repeating unit (y) having a group (Y) that increases and a repeating unit (z) containing a group (Z) that decomposes under the action of an acid. More preferably, a copolymer resin of the repeating unit (a), the repeating unit (y), and the repeating unit (z).
(C-8) A resin having a repeating unit (aX) having both an alkali-soluble group (X) and a group having a silicon atom, more preferably a resin having only a repeating unit (ax).
(C-9) a resin having a repeating unit (ay) having both a group (Y) that decomposes by the action of an alkali developer and increases the solubility in the alkali developer and a group having a silicon atom, more preferably , A resin having only repeating units (ay).
(C-10) A repeating unit (ax) having both an alkali-soluble group (X) and a group having a silicon atom, and a group (Y) that decomposes by the action of an alkali developer and increases the solubility in an alkali developer. A resin having a repeating unit (y) having a repeating unit, more preferably a copolymer resin of a repeating unit (ax) and a repeating unit (y).
(C-11) a resin having a repeating unit (ax) having both an alkali-soluble group (X) and a group having a silicon atom, and a repeating unit (z) having a group (Z) decomposed by the action of an acid, and more Preferably, a copolymer resin of a repeating unit (ax) and a repeating unit (z).
(C-12) a resin having a repeating unit (a) having a group having a silicon atom, and a repeating unit (ax) containing both an alkali-soluble group (X) and a group having a silicon atom, more preferably a repeating unit Copolymer resin of unit (a) and repeating unit (ax).
(C-13) A repeating unit (a) having a group having a silicon atom, a group (Y) which decomposes by the action of an alkali developer and increases the solubility in the alkali developer, and a group having a silicon atom A resin having a repeating unit (ay), more preferably a copolymer resin of the repeating unit (a) and the repeating unit (ay).
In the resins (C-1), (C-2) and (C-4), the introduction amount of the repeating unit (a) is preferably 40 to 99 mol%, more preferably 60 to 80%. preferable.
In the resin (C-10), the introduction amount of the repeating unit (ax) is preferably 40 to 99 mol%, and more preferably 60 to 90 mol%.

When the silicon atom-containing resin (C) contains (X) an alkali-soluble group and / or (Y) an alkali-hydrolyzable group, (X) an alkali-soluble group (acid group) or (Y) an alkali-hydrolyzable group ( The amount of acid groups generated by alkali hydrolysis is preferably 2 to 10 meq / g, more preferably 2 to 8 meq / g, as the acid value of the resin (C). The acid value is a measurement of the amount (mg) of potassium hydroxide required to neutralize the compound.
When the resin (C) contains a (Z) acid-decomposable group, the amount is preferably 5 to 100%, more preferably 10 to 100%, as the mol% of the repeating unit having an acid-decomposable group. .

The silicon atom contained in the silicon-containing resin (C) is preferably 2 to 50% by mass and more preferably 2 to 30% by mass with respect to the molecular weight of the resin (C). Moreover, it is preferable that the repeating unit containing a silicon atom is 10-100 mass% in resin (C), and is 20-20.
More preferably, it is 100 mass%.

  The weight average molecular weight of the silicon-containing resin (C) is preferably 1000 to 100,000, more preferably 1000 to 50,000.

  The silicon-containing resin (C) preferably has a residual monomer amount of 0 to 10% by mass, and more preferably 0 to 5% by mass. Further, from the viewpoint of resolution, resist shape, resist pattern side wall, roughness, etc., the molecular weight distribution (Mw / Mn, also referred to as dispersity) is preferably from 1 to 5, more preferably from 1 to 3. The

  The addition amount of the resin (C) in the positive resist composition is preferably 0.1 to 30% by mass, more preferably 0.1 to 10% by mass, and still more preferably based on the total solid content of the resist composition. Is 0.1-5 mass%.

  The silicon atom-containing resin (C) may be used alone or in combination.

  As with the resin (A), the silicon-containing resin (C) is naturally free of impurities such as metals, and the residual monomer and oligomer components are not more than predetermined values, for example, 0.1% by mass or the like by HPLC. It is preferable that not only the sensitivity, resolution, process stability, pattern shape, etc. as a resist can be further improved, but also a resist composition that is excellent in terms of changes over time such as foreign matter in liquid and sensitivity can be obtained. .

As the silicon-containing resin (C), various commercially available products can be used or synthesized by a conventional method. For example, in the case of a resin, it can be obtained by radical polymerization as in the synthesis of the acid-decomposable resin (A) described above and general purification.
As a polymerization initiator, V601, V60, V65 (made by Wako Pure Chemical Industries, Ltd.) etc. can be used, for example. Moreover, a polymerization reaction can be controlled using a chain transfer agent.

(D) Organic solvent Solvents that can be used when preparing the positive resist composition by dissolving the above components include, for example, alkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, and lactate alkyl ester. Alkoxypropionate alkyl, cyclic lactone having 4 to 10 carbon atoms, monoketone compound having 4 to 10 carbon atoms which may contain a ring, alkylene carbonate, alkyl alkoxyacetate, alkyl pyruvate and the like.

Examples of the alkylene glycol monoalkyl ether carboxylate include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl Preferred examples include ether propionate, ethylene glycol monomethyl ether acetate, and ethylene glycol monoethyl ether acetate.
Preferred examples of the alkylene glycol monoalkyl ether include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether.

Preferred examples of the alkyl lactate include methyl lactate, ethyl lactate, propyl lactate and butyl lactate.
Preferable examples of the alkyl alkoxypropionate include ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl 3-methoxypropionate.

  Examples of the cyclic lactone having 4 to 10 carbon atoms include β-propiolactone, β-butyrolactone, γ-butyrolactone, α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone, γ- Caprolactone, γ-octanoic lactone, and α-hydroxy-γ-butyrolactone are preferred.

  Examples of the monoketone compound having 4 to 10 carbon atoms which may contain a ring include 2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone, 3-methyl-2-pentanone, 4- Methyl-2-pentanone, 2-methyl-3-pentanone, 4,4-dimethyl-2-pentanone, 2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2 -Hexanone, 3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4 -Heptanone, 2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone, 5-he Sen-2-one, 3-penten-2-one, cyclopentanone, 2-methylcyclopentanone, 3-methylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopenta Non, cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, 2,2-dimethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone, 2-methylcyclo Preferred are heptanone and 3-methylcycloheptanone.

Preferred examples of the alkylene carbonate include propylene carbonate, vinylene carbonate, ethylene carbonate, and butylene carbonate.
Examples of the alkyl alkoxyacetate include 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2- (2-ethoxyethoxy) ethyl acetate, 3-methoxy-3-methylbutyl acetate, and 1-methoxy-acetate. 2-propyl is preferred.
Preferred examples of the alkyl pyruvate include methyl pyruvate, ethyl pyruvate, and propyl pyruvate.
As a solvent which can be preferably used, a solvent having a boiling point of 130 ° C. or higher under normal temperature and normal pressure can be mentioned. Specifically, cyclopentanone, γ-butyrolactone, cyclohexanone, ethyl lactate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, ethyl 3-ethoxypropionate, ethyl pyruvate, 2-ethoxyethyl acetate, acetic acid -2- (2-ethoxyethoxy) ethyl and propylene carbonate are mentioned.
In the present invention, the above solvents may be used alone or in combination of two or more.

In this invention, you may use the mixed solvent which mixed the solvent which contains a hydroxyl group in a structure, and the solvent which does not contain a hydroxyl group as an organic solvent.
Examples of the solvent containing a hydroxyl group include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethyl lactate, and the like. Particularly preferred are propylene glycol monomethyl ether and ethyl lactate.
Examples of the solvent not containing a hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide and the like. Among these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are particularly preferable, and propylene glycol monomethyl ether acetate, ethyl ethoxypropionate. 2-heptanone is most preferred.
The mixing ratio (mass) of the solvent containing a hydroxyl group and the solvent not containing a hydroxyl group is 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 60/40. . A mixed solvent containing 50% by mass or more of a solvent not containing a hydroxyl group is particularly preferred from the viewpoint of coating uniformity.

(E) Basic compound The positive resist composition of the present invention preferably contains (E) a basic compound in order to reduce a change in performance over time from exposure to heating.
Preferred examples of the basic compound include compounds having structures represented by the following formulas (A) to (E).

In general formulas (A) to (E),
R ²⁰⁰ , R ²⁰¹ and R ²⁰² may be the same or different and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms. Here, R ²⁰¹ and R ²⁰² may combine with each other to form a ring.

The alkyl group may be unsubstituted or may have a substituent. Examples of the alkyl group having a substituent include an aminoalkyl group having 1 to 20 carbon atoms, a hydroxyalkyl group having 1 to 20 carbon atoms, Or a C1-C20 cyanoalkyl group is preferable.
R ²⁰³ , R ²⁰⁴ , R ²⁰⁵ and R ²⁰⁶ may be the same or different and each represents an alkyl group having 1 to 20 carbon atoms.
The alkyl groups in these general formulas (A) to (E) are more preferably unsubstituted.

  Preferred compounds include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, piperidine and the like, and more preferred compounds include imidazole structure, diazabicyclo structure, onium hydroxide structure, onium carboxylate Examples thereof include a compound having a structure, a trialkylamine structure, an aniline structure or a pyridine structure, an alkylamine derivative having a hydroxyl group and / or an ether bond, and an aniline derivative having a hydroxyl group and / or an ether bond.

Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, and benzimidazole. Examples of the compound having a diazabicyclo structure include 1,4-diazabicyclo [2,2,2] octane, 1,5-diazabicyclo [4,3,0] non-5-ene, and 1,8-diazabicyclo [5,4,0. ] Undecar 7-ene etc. are mentioned. Examples of the compound having an onium hydroxide structure include triarylsulfonium hydroxide, phenacylsulfonium hydroxide, sulfonium hydroxide having a 2-oxoalkyl group, specifically triphenylsulfonium hydroxide, tris (t-butylphenyl) sulfonium. Examples thereof include hydroxide, bis (t-butylphenyl) iodonium hydroxide, phenacylthiophenium hydroxide, and 2-oxopropylthiophenium hydroxide. As the compound having an onium carboxylate structure, an anion portion of the compound having an onium hydroxide structure is converted to a carboxylate, and examples thereof include acetate, adamantane-1-carboxylate, and perfluoroalkylcarboxylate. Examples of the compound having a trialkylamine structure include tri (n-butyl) amine and tri (n-octyl) amine. Examples of the aniline compound include 2,6-diisopropylaniline, N, N-dimethylaniline, N, N-dibutylaniline, N, N-dihexylaniline and the like. Examples of the alkylamine derivative having a hydroxyl group and / or an ether bond include ethanolamine, diethanolamine, triethanolamine, and tris (methoxyethoxyethyl) amine. Examples of aniline derivatives having a hydroxyl group and / or an ether bond include N, N-bis (hydroxyethyl) aniline.
These basic compounds are used alone or in combination of two or more.

  The usage-amount of a basic compound is 0.001-10 mass% normally on the basis of solid content of a positive resist composition, Preferably it is 0.01-5 mass%.

  The use ratio of the acid generator and the basic compound in the composition is preferably acid generator / basic compound (molar ratio) = 2.5 to 300. In other words, the molar ratio is preferably 2.5 or more from the viewpoint of sensitivity and resolution, and is preferably 300 or less from the viewpoint of suppressing the reduction in resolution due to the thickening of the resist pattern over time until post-exposure heat treatment. The acid generator / basic compound (molar ratio) is more preferably 5.0 to 200, still more preferably 7.0 to 150.

(F) Surfactant The positive resist composition of the present invention preferably further contains (F) a surfactant, and is a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant, silicon-based interface). It is more preferable to contain any one or two or more of an activator and a surfactant having both a fluorine atom and a silicon atom.

When the positive resist composition of the present invention contains the surfactant (F), a resist having good sensitivity and resolution and less adhesion and development defects when using an exposure light source of 250 nm or less, particularly 220 nm or less. A pattern can be given.
Examples of the fluorine-based and / or silicon-based surfactant include, for example, JP-A No. 62-36663, JP-A No. 61-226746, JP-A No. 61-226745, JP-A No. 62-170950, JP 63-34540 A, JP 7-230165 A, JP 8-62834 A, JP 9-54432 A, JP 9-5988 A, JP 2002-277862 A, US Patent Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511, 5,824,451 Surfactant can be mentioned, The following commercially available surfactant can also be used as it is.
Examples of commercially available surfactants that can be used include F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431, 4430 (manufactured by Sumitomo 3M Co., Ltd.),
Megafuck F171, F173, F176, F189, F113, F110, F177, F120, R08 (manufactured by Dainippon Ink and Chemicals), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass ( Co., Ltd.), Troisol S-366 (manufactured by Troy Chemical Co., Ltd.), GF-300, GF-150 (manufactured by Toagosei Co., Ltd.), Surflon S-393 (manufactured by Seimi Chemical Co., Ltd.), Ftop EF121, EF122A, EF122B, RF122C, EF125M, EF135M, EF351, 352, EF801, EF802, EF601 (manufactured by Gemco), PF636, PF656, PF6320, PF6520 (manufactured by OMNIVA), FTX-18204, 208, 230G, 204 , Mention may be made of 208D, 212D, the fluorine-based surfactant or silicone-based surfactants such as 218D and 222D ((KK) Neos). 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). A unit having different chain lengths in the same chain length, such as a block link) or poly (block link of oxyethylene and oxypropylene) may be used. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates).

Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₃ F ₇ group and (poly (oxy) And a copolymer of (ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate).

  In the present invention, other surfactants other than fluorine-based and / or silicon-based surfactants can also be used. Specifically, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether, etc. Sorbitans such as polyoxyethylene alkyl allyl ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate Fatty acid esters, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopal Te - DOO, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, may be mentioned polyoxyethylene sorbitan tristearate nonionic surfactants of polyoxyethylene sorbitan fatty acid esters such as such.

These surfactants may be used alone or in several combinations.

  (F) The usage-amount of surfactant becomes like this. Preferably it is 0.01-10 mass% with respect to positive resist composition whole quantity (except a solvent), More preferably, it is 0.1-5 mass%.

(H) Carboxylic acid onium salt The positive resist composition in the present invention may contain (H) a carboxylic acid onium salt. Examples of the carboxylic acid onium salt include a carboxylic acid sulfonium salt, a carboxylic acid iodonium salt, and a carboxylic acid ammonium salt. In particular, the (H) carboxylic acid onium salt is preferably an iodonium salt or a sulfonium salt. Furthermore, it is preferable that the carboxylate residue of the (H) carboxylic acid onium salt of the present invention does not contain an aromatic group or a carbon-carbon double bond. As a particularly preferable anion moiety, a linear, branched, monocyclic or polycyclic alkylcarboxylic acid anion having 1 to 30 carbon atoms is preferable. More preferably, an anion of a carboxylic acid in which some or all of these alkyl groups are fluorine-substituted is preferable. The alkyl chain may contain an oxygen atom. This ensures transparency with respect to light of 220 nm or less, improves sensitivity and resolution, and improves density dependency and exposure margin.

  Fluoro-substituted carboxylic acid anions include fluoroacetic acid, difluoroacetic acid, trifluoroacetic acid, pentafluoropropionic acid, heptafluorobutyric acid, nonafluoropentanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorocyclohexanecarboxylic acid, 2 , 2-bistrifluoromethylpropionic acid anion and the like.

  These (H) carboxylic acid onium salts can be synthesized by reacting sulfonium hydroxide, iodonium hydroxide, ammonium hydroxide and carboxylic acid with silver oxide in a suitable solvent.

  The content of (H) carboxylic acid onium salt in the composition is suitably from 0.1 to 20% by weight, preferably from 0.5 to 10% by weight, more preferably 1%, based on the total solid content of the composition. -7% by mass.

Other Additives The positive resist composition of the present invention further promotes solubility in dyes, plasticizers, photosensitizers, light absorbers, alkali-soluble resins, dissolution inhibitors and developers as necessary. A compound (for example, a phenol compound having a molecular weight of 1000 or less, an alicyclic compound having a carboxyl group, or an aliphatic compound) and the like can be contained.

Such phenolic compounds having a molecular weight of 1000 or less can be obtained by referring to, for example, the methods described in JP-A-4-1222938, JP-A-2-28531, US Pat. No. 4,916,210, European Patent 219294, etc. It can be easily synthesized by those skilled in the art.
Specific examples of alicyclic or aliphatic compounds having a carboxyl group include carboxylic acid derivatives having a steroid structure such as cholic acid, deoxycholic acid, lithocholic acid, adamantane carboxylic acid derivatives, adamantane dicarboxylic acid, cyclohexane carboxylic acid, cyclohexane Examples thereof include, but are not limited to, dicarboxylic acids.

[Physical properties of resist composition]
The positive resist composition of the present invention is preferably used at a film thickness of 30 to 250 nm, more preferably at a film thickness of 30 to 200 nm, from the viewpoint of improving resolution. Such a film thickness can be obtained by setting the solid content concentration in the positive resist composition to an appropriate range to give an appropriate viscosity and improving the coating property and film forming property.
The total solid concentration in the positive resist composition is generally 1 to 10% by mass, more preferably 1 to 8% by mass, and still more preferably 1.0 to 7.0% by mass.

[Pattern formation method]
The positive resist composition of the present invention is used by dissolving the above components in a predetermined organic solvent, preferably the mixed solvent, filtering the solution, and then applying the solution on a predetermined support as follows. The filter used for filter filtration is preferably made of polytetrafluoroethylene, polyethylene, or nylon of 0.1 microns or less, more preferably 0.05 microns or less, and still more preferably 0.03 microns or less.

For example, a positive resist composition is coated on a substrate (eg, silicon / silicon dioxide coating) used in the manufacture of precision integrated circuit elements by a suitable coating method such as a spinner or a coater, and dried to form a photosensitive film. Form.
The photosensitive film is irradiated with actinic rays or radiation through a predetermined mask, preferably baked (heated), developed and rinsed. Thereby, a good pattern can be obtained.

Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, etc., preferably 250 nm or less, more preferably 220 nm or less, and even more preferably 200 nm or less. Vacuum ultraviolet light having a wavelength of, specifically, KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (157 nm), X-ray, electron beam, etc., ArF excimer laser, F ₂ excimer Laser, EUV (13 nm) and electron beam are preferred.

Before forming the photosensitive film, an antireflection film may be coated on the substrate in advance.
As the antireflection film, any of an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, and amorphous silicon, and an organic film type made of a light absorber and a polymer material can be used. In addition, as the organic antireflection film, commercially available organic antireflection films such as DUV30 series, DUV-40 series manufactured by Brewer Science, and AR-2, AR-3, AR-5 manufactured by Shipley may be used. it can.

In the development step, an alkaline developer is used as follows. As an alkaline developer of the resist composition, inorganic hydroxides such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, primary amines such as ethylamine and n-propylamine, Secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide and the like Alkaline aqueous solutions such as quaternary ammonium salts, cyclic amines such as pyrrole and pihelidine can be used.
Furthermore, alcohols and surfactants can be added in appropriate amounts to the alkaline developer.
The alkali concentration of the alkali developer is usually from 0.1 to 20% by mass.
The pH of the alkali developer is usually from 10.0 to 15.0.
Furthermore, alcohols and surfactants can be added in appropriate amounts to the alkaline aqueous solution.
As a developing method, for example, a developing solution is supplied onto a resist film provided on the substrate, and a paddle is formed on the resist film to form a paddle with the developing solution, or the substrate is stationary, or the substrate is rotated at a low speed. Alternatively, a developing method may be used in which a developing solution is supplied onto a resist film provided on the substrate and the substrate is rotated at high speed without forming a paddle of the developing solution on the resist film.
As the rinsing liquid, pure water can be used, and an appropriate amount of a surfactant can be added.
Further, after the development process or the rinsing process, a process of removing the developer or the rinsing liquid adhering to the pattern with a supercritical fluid can be performed.

Exposure (immersion exposure) may be performed by filling a liquid (immersion medium) having a higher refractive index than air between the resist film and the lens during irradiation with actinic rays or radiation. Thereby, resolution can be improved. As the immersion medium to be used, any liquid can be used as long as it has a higher refractive index than air, but pure water is preferred. Further, an overcoat layer may be further provided on the photosensitive film so that the immersion medium and the photosensitive film do not come into direct contact with each other during the immersion exposure. Thereby, the elution of the composition from the photosensitive film to the immersion medium is suppressed, and development defects are reduced.
Before or after the immersion exposure process (or both), the surface of the resist film can be cleaned with a cleaning liquid. The cleaning liquid may be aqueous or organic, but is preferably water or a water-miscible organic solvent such as methanol, ethanol, or isopropyl alcohol. By performing a cleaning process before and after the immersion exposure process, dust and particles on the surface of the resist film can be reduced and defect performance can be improved.

The immersion liquid used for the immersion exposure will be described below.
The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has a refractive index temperature coefficient as small as possible so as to minimize distortion of the optical image projected onto the resist. In the case of an ArF excimer laser (wavelength: 193 nm), it is preferable to use water from the viewpoints of availability and ease of handling in addition to the above-described viewpoints.
Further, a medium having a refractive index of 1.5 or more can be used in that the refractive index can be further improved. This medium may be an aqueous solution or an organic solvent.

  When water is used as the immersion liquid, the surface tension of the water is decreased and the surface activity is increased, so that the resist layer on the wafer is not dissolved and the influence on the optical coating on the lower surface of the lens element can be ignored. An additive (liquid) may be added in a small proportion. The additive is preferably an aliphatic alcohol having a refractive index substantially equal to that of water, and specifically includes methyl alcohol, ethyl alcohol, isopropyl alcohol and the like. By adding an alcohol having a refractive index substantially equal to that of water, even if the alcohol component in water evaporates and the content concentration changes, an advantage that the change in the refractive index of the entire liquid can be made extremely small can be obtained. On the other hand, when an opaque substance or impurities whose refractive index is significantly different from that of water are mixed with respect to 193 nm light, the optical image projected on the resist is distorted. Therefore, distilled water is preferable as the water to be used. Further, pure water filtered through an ion exchange filter or the like may be used.

The electrical resistance of water is desirably 18.3 MQcm or more, the TOC (organic substance concentration) is desirably 20 ppb or less, and deaeration treatment is desirably performed.
Moreover, it is possible to improve lithography performance by increasing the refractive index of the immersion liquid. From such a viewpoint, an additive for increasing the refractive index may be added to water, or heavy water (D ₂ O) may be used instead of water.

Since the resist film is not directly brought into contact with the immersion liquid between the resist film of the positive resist composition of the present invention and the immersion liquid, it is also referred to as an “immersion liquid hardly soluble film” (hereinafter referred to as “topcoat”). ) May be provided. The necessary functions for the top coat are suitability for application to the upper layer of the resist, radiation, especially transparency to 193 nm, and poor immersion liquid solubility. It is preferable that the top coat is not mixed with the resist and can be uniformly applied to the resist upper layer.
From the viewpoint of 193 nm transparency, the topcoat is preferably a polymer that does not contain an aromatic, and specifically, a hydrocarbon polymer, an acrylate polymer, a polymethacrylic acid, a polyacrylic acid, a polyvinyl ether, a silicon-containing polymer, And fluorine-containing polymers. From the viewpoint of contaminating the optical lens when impurities are eluted from the top coat into the immersion liquid, it is preferable that the residual monomer component of the polymer contained in the top coat is small.

When peeling the top coat, a developer may be used, or a separate release agent may be used. As the release agent, a solvent having a small penetration into the resist is preferable. It is preferable that the peeling process can be performed with an alkali developer in that the peeling process can be performed simultaneously with the resist development process. From the viewpoint of peeling with an alkaline developer, the topcoat is preferably acidic, but may be neutral or alkaline from the viewpoint of non-intermixability with the resist.
The resolution is improved when there is no difference in refractive index between the top coat and the immersion liquid. In the case of using water as the immersion liquid in an ArF excimer laser (wavelength: 193 nm), the top coat for ArF immersion exposure is preferably close to the refractive index of the immersion liquid. From the viewpoint of making the refractive index close to the immersion liquid, it is preferable to have fluorine atoms in the topcoat. A thin film is more preferable from the viewpoint of transparency and refractive index.

  It is preferred that the top coat is not mixed with the resist and further not mixed with the immersion liquid. From this viewpoint, when the immersion liquid is water, the topcoat solvent is preferably a resist solvent hardly soluble and water-insoluble medium. Furthermore, when the immersion liquid is an organic solvent, the topcoat may be water-soluble or water-insoluble.

  When the resist composition of the present invention is used as a resist film, the receding contact angle of water with respect to the resist film is preferably 65 ° or more. In particular, it is preferably 65 to 80 °. Moreover, it is preferable that the receding contact angle of water with respect to the resin film which consists only of resin (C) is 70-110 degrees. Here, the receding contact angle is at normal temperature and pressure. The receding contact angle is a contact angle when the droplet interface recedes from the surface of the resist film.

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

Examples 1 to 74 and Comparative Examples 1 to 3
The structure, composition (molar ratio, corresponding to each repeating unit in order from the left), weight average molecular weight (Mw), and dispersity (Mw / Mn) of the resin (A) used in Examples and Comparative Examples are shown below.

Synthesis Example (1) Synthesis of Resin (C-1) Methyl methacrylate (trimethylsilyl) methyl and methacrylic acid were charged at a ratio of 50/50 and dissolved in propylene glycol monomethyl ether acetate to prepare 450 g of a solution having a solid content concentration of 22%. did. To this solution, 5 mol% of a polymerization initiator V-601 manufactured by Wako Pure Chemical Industries, Ltd. was added, and this was added dropwise to 50 mL of propylene glycol monomethyl ether acetate heated to 80 ° C. over 2 hours in a nitrogen atmosphere. After completion of dropping, the reaction solution was stirred for 2 hours to obtain a reaction solution (C-1). After completion of the reaction, the reaction solution (C-1) is cooled to room temperature, crystallized in a mixed solvent of 10 times the amount of hexane / ethyl acetate = 90/10, and the precipitated white powder is collected by filtration to obtain the desired product. Resin (C-1) was recovered.
^The polymer composition ratio determined from ¹³ CNMR and acid value titration was 50/50. Moreover, the standard polystyrene conversion weight average molecular weight calculated | required by GPC measurement was 13200, and dispersion degree was 2.2.

Synthesis Example (2) Synthesis of Resin (C-2) Using the same method as in Synthesis Example (1), Resin (C-2) was synthesized with a charge composition of 30/70. Methanol was used as a solvent for crystallization. ^The polymer composition ratio determined from ¹³ CNMR and acid value titration was 32/68. Moreover, the standard polystyrene conversion weight average molecular weight calculated | required by GPC measurement was 13000, and dispersion degree was 2.1.

Synthesis Example (3) Synthesis of Resin (C-3) Allyltrimethylsilane, maleic anhydride, and t-butyl methacrylate were charged at a ratio of 40/40/20, dissolved in propylene glycol monomethyl ether acetate, and a solid content concentration of 50 450 g of a% solution was prepared. To this solution, 4 mol% of a polymerization initiator V-65 manufactured by Wako Pure Chemical Industries, Ltd. was added and stirred for 5 hours in a nitrogen atmosphere to obtain a reaction solution (C-3). After completion of the reaction, the reaction solution (C-3) is cooled to room temperature, crystallized in a mixed solvent of 5 times amount of methanol, and the precipitated white powder is collected by filtration to obtain the target resin (C-3). It was collected.
^The polymer composition ratio determined from ¹³ CNMR was 35/35/30. Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 8500, and dispersion degree was 1.8.

Synthesis Example (4) Synthesis of Resin (C-4) Allyltrimethylsilane, N-ethylmaleimide and methacrylic acid were charged at a ratio of 35/35/30 and dissolved in tetrahydrofuran to prepare 300 g of a solution having a solid content of 80%. did. To this solution, 5 mol% of a polymerization initiator V-65 manufactured by Wako Pure Chemical Industries, Ltd. was added, and this was added dropwise to 30 mL of tetrahydrofuran heated to 65 ° C. over 4 hours in a nitrogen atmosphere. The reaction liquid was stirred for 2 hours after completion | finish of dripping, and the reaction liquid (C-4) was obtained. After completion of the reaction, the reaction solution (C-4) is cooled to room temperature, crystallized in a mixed solvent of 5 times amount of hexane / ethyl acetate = 90/10, and the precipitated white powder is collected by filtration to obtain the desired product. Resin (C-4) was recovered.
^The polymer composition ratio determined from ¹³ C-NMR and acid value titration was 32/32/36. Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 10000, and dispersion degree was 2.1.

Synthesis Example (5) Synthesis of Resin (C-5) Methacryloxypropylheptaethyl-T8-silsesquioxane and methacrylic acid were charged at a ratio of 40/60, dissolved in tetrahydrofuran, and 450 g of a solution having a solid content of 50%. Was prepared. To this solution, 4 mol% of a polymerization initiator V-65 manufactured by Wako Pure Chemical Industries, Ltd. was added and stirred for 5 hours in a nitrogen atmosphere to obtain a reaction liquid (C-5). After completion of the reaction, the reaction solution (C-5) is cooled to room temperature, crystallized in a mixed solvent of 10 amounts of methanol, and the precipitated white powder is collected by filtration to recover the target resin (C-5). did.
^The polymer composition ratio determined from ¹³ CNMR was 35/65. Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 8500, and dispersion degree was 1.8.

  Furthermore, Resins (C-6) to (C-12) could be obtained by the same method as in this synthesis example. Weight average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement of (C-6) to (C-12), composition ratio (molar ratio, corresponding to each repeating unit in order from the left), dispersity (Mw / Mn ) Are summarized in Table 4 below.

<Resist preparation>
The components shown in Tables 7 to 10 below were dissolved in a solvent, and a solution with a solid content concentration of 7% by mass was prepared for each, and this was filtered through a 0.1 μm polyethylene filter to prepare a positive resist solution. The prepared positive resist composition was evaluated by the following method, and the results are shown in Tables 7 to 10 below. In addition, about each component in Tables 7-10, ratio when using two or more is a mass ratio.

[Image performance test]
(Exposure condition (1))
An organic antireflection film ARC29A (Nissan Chemical Co., Ltd.) was applied on a silicon wafer and baked at 205 ° C. for 60 seconds to form a 78 nm antireflection film. The positive resist composition prepared thereon was applied, and baked at 120 ° C. for 60 seconds to form a 250 nm resist film. The obtained wafer was subjected to pattern exposure using an ArF excimer laser scanner (PAS5500 / 1100, manufactured by ASML, NA0.75, σo / σi = 0.85 / 0.55). Thereafter, heating was performed at 120 ° C. for 60 seconds, followed by development with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsing with pure water, and spin drying to obtain a resist pattern.

(Exposure condition (2))
This condition is to form a resist pattern by an immersion exposure method using pure water.
An organic antireflection film ARC29A (Nissan Chemical Co., Ltd.) was applied on a silicon wafer and baked at 205 ° C. for 60 seconds to form a 78 nm antireflection film. The positive resist composition prepared thereon was applied, and baked at 120 ° C. for 60 seconds to form a 250 nm resist film. The obtained wafer was subjected to pattern exposure using an ArF excimer laser immersion scanner (NA 0.75). As the immersion liquid, ultrapure water having a specific resistivity of 18.0 MΩ or more was used. Thereafter, heating was performed at 120 ° C. for 60 seconds, followed by development with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsing with pure water, and spin drying to obtain a resist pattern.
In addition, about Examples 61-74, the same process was performed on the conditions of following Table 6, and the resist pattern was obtained.

[Profile]
The profile of the obtained pattern was observed and evaluated with a scanning electron microscope (S-9260, manufactured by Hitachi, Ltd.).

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

[Water followability]
The prepared positive resist composition was applied on a silicon wafer and baked at 115 ° C. for 60 seconds to form a 200 nm resist film. Next, as shown in FIG. 2, 15 ml of distilled water was dropped on the center of the obtained wafer 12 coated with the positive resist composition with a pipette. A 10 cm square quartz plate 14 with a string 13 was placed on the distilled water paddle so that the entire gap between the wafer 12 and the quartz plate 14 was filled with distilled water 15.
Next, with the wafer 12 fixed, the string 13 attached to the quartz plate 14 is wound around the rotating portion of the motor 16 that rotates at a speed of 30 cm / second, and the motor 16 is switched on for 0.5 seconds to switch the quartz plate 14. Moved. After the movement of the quartz plate 14, the amount of distilled water remaining under the quartz plate 14 was judged according to the following criteria, and used as an index of water followability.
In FIG. 3, (a) to (d) schematically show various patterns obtained by observing the quartz plate from above after the quartz plate is moved, and the hatched portion 17 indicates the distillation remaining under the quartz plate. In the water region, the blank portion 18 is a region where distilled water cannot follow the movement of the quartz plate and air has entered.
As shown in (a), the case where distilled water remains on the entire surface of the quartz plate after moving the quartz plate is as follows: ○, as shown in (b), the area where air enters is about 10% of the area of the quartz plate As shown in Δ, (c), (d), the area where air enters is 20% or more with respect to the area of the quartz plate.

[Measurement of receding contact angle]
A positive resist composition prepared on a silicon wafer was spin-coated and then baked on a hot plate to form a 200 nm resist film. The receding contact angle of water droplets was measured by the expansion / contraction method of a dynamic contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.). An initial droplet size of 35 μL was sucked at a rate of 6 μL / sec for 5 seconds, and a value with a stable dynamic contact angle during suction was defined as a receding contact angle.
These evaluation results are shown in Tables 7-10.

The symbols in Tables 7 to 10 are as follows.
The acid generator corresponds to that exemplified above.

N-1: N, N-dibutylaniline N-2: N, N-dihexylaniline N-3: 2,6-diisopropylaniline N-4: tri-n-octylamine N-5: N, N-dihydroxyethyl Aniline N-6: 2,4,5-triphenylimidazole N-7: Triethanolamine N-8: Tetrabutylammonium hydroxide N-9: Phenylbenzimidazole

W-1: Megafuck F176 (Dainippon Ink Chemical Co., Ltd.)
(Fluorine)
W-2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.)
(Fluorine and silicon)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.)
(Silicon)
W-4: Troisol S-366 (manufactured by Troy Chemical Co., Ltd.)
W-5: PF656 (manufactured by OMNOVA, fluorine-based)
W-6: PF6320 (manufactured by OMNOVA, fluorine-based)
W-7: PF6520 (manufactured by OMNOVA, fluorine-based)

SL-1: Cyclohexanone SL-2: Propylene glycol monomethyl ether acetate SL-3: Ethyl lactate SL-4: Propylene glycol monomethyl ether SL-5: γ-butyrolactone SL-6: Propylene carbonate

  From these results, it can be seen that the resist composition of the present invention is excellent in line edge roughness and excellent in water followability.

It is the schematic of receding contact angle. It is the schematic which shows the state which is evaluating the water followability to a quartz plate. It is the schematic which shows the water followability to a quartz plate.

Explanation of symbols

12 resist-coated wafer 13 string 14 quartz plate 15 distilled water 16 motor 17 area where distilled water remains under the quartz plate 18 area where air enters under the quartz plate

Claims (12)

(A) a resin having no silicon atom whose solubility in an alkaline developer is increased by the action of an acid;
(B) a compound that generates an acid upon irradiation with an actinic ray or radiation,
(C) a silicon atom-containing resin having at least one group selected from the following groups (X) to (Z), and
(X) an alkali-soluble group,
(Y) a group that decomposes by the action of an alkali developer and increases the solubility of the resin (C) in the alkali developer; and (Z) a group that decomposes by the action of an acid and increases the solubility of the resin (C) in the alkali developer;
(D) A positive resist composition containing a solvent.   2. The positive resist composition according to claim 1, wherein the resin (A) has a monocyclic or polycyclic alicyclic hydrocarbon structure. 3. The positive resist composition according to claim 1, wherein the silicon atom-containing resin (C) is a silicon atom-containing resin that is soluble in alkali and / or has increased solubility in an alkali developer by the action of an acid. object.   4. The positive resist according to claim 1, wherein the silicon atom-containing resin (C) is a resin that is alkali-soluble and does not increase the solubility in an alkali developer due to the action of an acid. Composition.   The positive resist composition according to any one of claims 1 to 3, wherein the silicon atom-containing resin (C) has at least one repeating unit having a lactone group.   4. The positive resist according to claim 1, wherein the silicon atom-containing resin (C) is a resin that is insoluble in alkali and has increased solubility in an alkali developer by the action of an acid. Composition.   The positive resist composition according to claim 1, wherein the positive resist composition is exposed to vacuum ultraviolet light having a wavelength of 200 nm or less.   8. The positive resist composition according to claim 1, wherein the silicon atom-containing resin (C) has a weight average molecular weight of 1,000 to 100,000.   The positive resist composition according to claim 1, wherein the silicon atom-containing resin (C) further has a fluorine atom.   10. The positive resist according to claim 1, wherein the addition amount of the silicon atom-containing resin (C) is 0.1 to 5% by mass with respect to the total solid content in the composition. Composition.   The positive resist composition according to claim 1, wherein the resin (A) contains a repeating unit having an alicyclic hydrocarbon group substituted with a hydroxyl group or a cyano group. A pattern forming method comprising: forming a resist film from the resist composition according to any one of claims 1 to 11; and exposing and developing the resist film.

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