JP2008222840A - Manufacturing method of resin exhibiting increased alkali solubility by action of acid, positive photosensitive composition comprising resin, and pattern-forming method using positive photosensitive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a resin exhibiting increased alkali solubility by an action of an acid that exhibits improved LER and causes very few defects at the time of resist film formation, a positive photosensitive composition comprising the resin, and a pattern-forming method using the positive photosensitive composition. <P>SOLUTION: The manufacturing method of the resin exhibiting increased alkali solubility by an action of an acid comprises dissolving a monomer bearing an acid-dissociable dissolution-inhibiting group in a polymerization solvent and polymerizing the monomer using a polymerization initiator, where the polymerization is carried out by using at least two kinds of polymerization initiators. The positive photosensitive composition comprises (A) the resin exhibiting increased alkali solubility by an action of an acid obtained by the manufacturing method above and (B) a photo-acid generating agent generating an acid by irradiation with active rays or radiation. The pattern-forming method comprises using the positive photosensitive composition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a resin whose alkali solubility is increased by the action of an acid, which is used in the production of semiconductors such as ICs, the production of circuit boards such as liquid crystals and thermal heads, and other photofabrication processes. The present invention relates to a positive photosensitive composition containing a resin and a pattern forming method using the positive photosensitive composition. More specifically, a method for producing a resin whose alkali solubility is increased by the action of an acid, which is suitable for use as an exposure light source such as far ultraviolet light of 250 nm or less, preferably 220 nm or less, and an irradiation source using an electron beam, and the like. The present invention relates to a positive photosensitive composition and a pattern forming method using the positive photosensitive composition.

  The chemically amplified photosensitive composition generates an acid in the exposed area by irradiation with radiation such as far ultraviolet light, and the acid-catalyzed reaction causes the solubility of the active radiation irradiated area and non-irradiated area in the developer. This is a pattern forming material for changing the pattern to form a pattern on the substrate.

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

On the other hand, when a further short wavelength light source, for example, an ArF excimer laser (193 nm) is used as an exposure light source, the compound having an aromatic group exhibits a large absorption in the 193 nm region. It wasn't.
For this reason, an ArF excimer laser resist containing a resin having an alicyclic hydrocarbon structure has been developed. JP-A-2003-167347 (Patent Document 1) and JP-A-2003-223001 (Patent Document 2) describe a composition containing a resin having a polycyclic acid-decomposing repeating unit and a non-acid-decomposing repeating unit. Is described. These resins are chemically amplified resists that have an acid-labile protecting group that is dissociated by an acid, but sufficient resist performance can be obtained while further miniaturization of the resist pattern is required. Has become difficult. One of the most regarded problems among them is LER (Line Edge Roughness). LER is uneven unevenness seen on the side wall of the line when the resist pattern is formed. When the size of the unevenness (LER) is constant, the LER relative to the line width decreases as the line width decreases. The ratio of size is high. That is, as the size of the resist pattern becomes finer, LER becomes relatively important. Since LER greatly affects the performance, reliability, yield, and the like of semiconductor devices, improvement of LER is an important issue.
A general method for improving LER is to increase the diffusion length of the acid. It is also conceivable to control the mixing and dispersion of the low molecular weight polymer.
However, these methods involve a decrease in resolution, and there is a problem that they cannot be used when a fine resolution is required.
Japanese Patent Application Laid-Open No. 2006-098708 (Patent Document 3) shows that LER is improved by mixing resins polymerized with different polymerization initiators, but this is not sufficient.

JP 2003-167347 A Japanese Patent Laid-Open No. 2003-223001 JP 2006-098708 A

  The present invention has been made in view of the above-mentioned background, and its purpose is to contain a resin in which different terminal structures are introduced into the polymer main chain by performing polymerization using at least two polymerization initiators. , A process for producing a resin with improved LER and very few defects at the time of resist film formation, and increased alkali solubility by the action of an acid, a positive photosensitive composition containing the resin, and the positive photosensitive It is providing the pattern formation method using a composition.

  The present invention is as follows.

  (1) When producing a resin whose alkali solubility is increased by the action of an acid by dissolving at least a monomer having an acid dissociable, dissolution inhibiting group in a polymerization solvent and polymerizing using a polymerization initiator, polymerization is performed. A method for producing a resin in which alkali solubility is increased by the action of an acid, wherein polymerization is performed using at least two kinds of initiators.

  (2) At least (a′1) a (meth) acrylic acid ester having an acid dissociable, dissolution inhibiting group and (a′2) a (meth) acrylic acid ester having a lactone unit are dissolved in a polymerization solvent and polymerized. When producing a resin whose alkali solubility is increased by the action of an acid by polymerizing using an initiator, the resin is polymerized using at least two kinds of polymerization initiators. A method for producing a resin with increased properties.

  (3) The polymerization according to (1) or (2), wherein polymerization is performed by using at least one kind of a polymerization initiator having a cyano group and an initiator having an ester group as a polymerization initiator. Production method.

(4) (A) Resin that is produced by the production method according to any one of (1) to (3) and has increased alkali solubility by the action of an acid, and (B) an acid by irradiation with actinic rays or radiation. A positive photosensitive composition comprising a generated photoacid generator.

  (5) A pattern forming method comprising the steps of: forming a photosensitive film from the positive photosensitive composition as described in (4); and exposing and developing the photosensitive film.

  According to the present invention, a resin in which different terminal structures are introduced into the polymer main chain can be produced, and by using the resin, aggregation of the resin in the resist solvent is suppressed and the resin is uniformly dissolved in the resist solvent. Can do. Therefore, by using the resin produced by the production method of the present invention, it is possible to produce a positive photosensitive composition having a small LER and very few defects when forming a resist film.

Hereinafter, the best mode for carrying out the present invention will be described.
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) Resin whose alkali solubility is increased by the action of an acid In the present invention, at least a monomer having an acid dissociable, dissolution inhibiting group is dissolved in a polymerization solvent and polymerized using a polymerization initiator, When producing a resin whose alkali solubility is increased by the action of an acid (hereinafter, also referred to as “resin (A)”), at least two polymerization initiators are used.

The polymerization initiator is not particularly limited as long as it is generally used as a radical generator. For example, a polymerization initiator having a cyano group, a polymerization initiator having an ester group, a polymerization initiator having a carboxylic acid group, an amide group And a polymerization initiator having an organic peroxide.
Examples of the polymerization initiator having a cyano group include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (cyclohexane-1- Carbonitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), and the like.
Examples of the polymerization initiator having an ester group include dimethyl 2,2′-azobisisobutyrate, diethyl dimethyl 2,2′-azobisisobutyrate, dipropyl dimethyl 2,2′-azobisisobutyrate, and dimethyl 2,2′-azobisisobutyric acid. Diisopropyl, dimethyl 2,2′-azobisisobutyrate dibutyl, dimethyl 2,2′-azobisisobutyrate diisobutyl, dimethyl 2,2′-azobisisobutyrate di (2-hydroxyethyl), dimethyl 2,2′-azobisisobutyrate dibenzyl, dimethyl 2 , 2′-azobisisobutyrate diphenethyl, methyl-ethyl-2,2′-azobisisobutyrate dimethyl, methyl-phenethyl-2,2′-azobisisobutyrate dimethyl, methyl-t-butyl-2,2′-azobisisobutyrate dimethyl, etc. Can be mentioned.
Examples of the polymerization initiator having a carboxylic acid group include 4,4′-azobis (4-cyanovaleric acid).
Examples of the polymerization initiator having an amide group include 2,2′-azobis (2-methyl-N- (1,1-bis (hydroxymethyl) -2-hydroxyethyl) propionamide), 2,2′-. Azobis (2-methyl-N- (2- (1-hydroxybutyl)) propionamide), 2,2′-azobis (2-methyl-N- (2-hydroxyethyl)) propionamide), 2,2 ′ -Azobis (N- (2-propyl) -2-methylpropionamide), 2,2'-azobis (N-butyl-2-methylpropionamide), 2,2'-azobis (N-cyclohexyl-2-methyl) Propionamide) and the like.
Examples of the organic peroxide polymerization initiator include decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, bis (3,5,5-trimethylhexanoyl) peroxide, succinic acid peroxide, and t-butyl peroxide. And oxy-2-ethylhexanoate.

  A preferred combination of polymerization initiators includes a combination of a polymerization initiator having a cyano group and an initiator having an ester group.

  As a preferable combination of polymerization initiators, a combination of polymerization initiators in which the difference in temperature at which the amount of the polymerization initiator is halved when heated in the same solvent for 10 hours is within 10 ° C. can be exemplified. When the decomposition amount of the polymerization initiator is greatly different, the terminal structure introduced at the polymer terminal is constant, which is not preferable. The temperature and decomposition amount of the selected polymerization initiator in the solvent are described in, for example, Wako Pure Chemical Industries Azo Polymerization Initiators (third edition).

Although there is no restriction | limiting in the mixing ratio of a polymerization initiator, It is the ratio of 40: 60-60: 40 within 20 mol% with respect to the number-of-moles of a 1st polymerization initiator, for example, when using 2 types. More preferably, it is preferably within 10 mol%, particularly preferably equimolar.

  The addition amount of the polymerization initiator can be appropriately adjusted depending on the molecular weight of the target polymer, but is preferably 0.5 mol% to 30 mol%, more preferably 1 mol% to the total monomer. It is preferable that it is 20 mol%, More preferably, it is 2 mol%-15 mol%.

In the present invention, at least a monomer having an acid dissociable, dissolution inhibiting group is used as the monomer.
Examples of the repeating unit of the monomer having an acid dissociable, dissolution inhibiting group in the resin (A) include a repeating unit represented by the following general formula (II-AB).

In general 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).
However, Z ′ has a group (also referred to as “acid-dissociable, dissolution-inhibiting group” or “acid-decomposable group”) that is dissociated by the action of at least one acid to increase the solubility in an alkali developer.

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

In general formulas (II-AB1) and (II-AB2),
R ₁₃ ′ to R ₁₆ ′ each independently represents a hydrogen atom, a halogen atom, a cyano group, —COOH, —COOR ₅ , an acid-decomposable group, —C (═O) —XA′—R ₁₇ ′, Represents an alkyl group or a cycloalkyl group; However, at least one of R ₁₃ ′ to R ₁₆ ′ represents an acid-decomposable 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 formula (II-AB), examples of the halogen atom represented by R ₁₁ ′ and R ₁₂ ′ include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom.

Examples of the alkyl group for R ₁₁ ′ and R ₁₂ ′ include linear or branched alkyl groups 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 the resin, and in particular, a bridged alicyclic ring An atomic group for forming a bridged alicyclic structure forming a repeating unit of the formula hydrocarbon is preferred.

Examples of the skeleton of the alicyclic hydrocarbon formed include those similar to the cycloalkyl groups of R _{12 to} R _{25 in} the general formulas (pI) to (pV) described later.

The atomic group for forming the alicyclic structure of Z ′ has at least one acid-decomposable group.
Examples of the acid-decomposable group include a group in which a hydrogen atom of an alkali-soluble group such as a carboxyl group or a hydroxyl group is protected with a group capable of leaving by the action of an acid.
Examples of the group capable of leaving by the action of an acid include —C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ), —C (R ₀₁ ) ( R ₀₂ ) (OR ₃₉ ) and the like.
In the formula, R _{36 to} R ₃₉ each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R ₃₆ and R ₃₇ may be bonded to each other to form a ring.
R _{01 and} R ₀₂ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group.

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 resin (A), the acid-decomposable repeating unit is a repeating unit having a partial structure containing an alicyclic hydrocarbon represented by the following general formula (pI) to general formula (pV), a general formula (II-AB). ) And at least one repeating unit among the repeating units of the copolymerization component described below.
One acid-decomposable repeating unit may be used, but it is preferable to use two or more acid-decomposable repeating units having different numbers of carbon atoms in the acid leaving group. Thereby, the balance between the resolution and the exposure latitude is improved.

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 the 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 repeating unit is preferably a repeating unit having a monocyclic alicyclic hydrocarbon group.

(A′1) (Meth) acrylic acid ester having acid dissociable dissolution inhibiting group The monomer having an acid dissociable dissolution inhibiting group is preferably a (meth) acrylic acid ester having an acid dissociable dissolution inhibiting group.
The (meth) acrylic acid ester having an acid dissociable, dissolution inhibiting group preferably has a partial structure containing an alicyclic hydrocarbon represented by the following general formula (pI) to general formula (pV).

In general formulas (pI) to (pV),
R ₁₁ represents an alkyl group.
Z represents an atomic group necessary for forming a cycloalkyl group together with a carbon atom.
R _{12 to} R ₁₆ each independently represents an alkyl group or a cycloalkyl group.
R _{17 to} R ₂₁ each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group.
R _{22 to} R ₂₅ each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group. R ₂₃ and R ₂₄ may be bonded to each other to form a ring.

In the general formulas (pI) to (pV), the alkyl group in R _{11 to} R ₂₅ is preferably a linear or branched alkyl group having 1 to 4 carbon atoms.

The cycloalkyl group represented by R _{12 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.

  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, a cyclododecanyl group, etc. can be mentioned. More preferable examples include an adamantyl group, norbornyl group, cyclohexyl group, cyclopentyl group, tetracyclododecanyl group, and tricyclodecanyl group.

The above alkyl group and cycloalkyl group may have a substituent.
As a substituent of an alkyl group or a cycloalkyl group, an alkyl group (1 to 4 carbon atoms), a halogen atom, a hydroxyl group, an alkoxy group (1 to 4 carbon atoms), a carboxyl group, an alkoxycarbonyl group (2 to 6 carbon atoms) Is mentioned. 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 acid dissociable, dissolution inhibiting group in the present invention can be used for protecting an alkali-soluble group depending on the structure represented by the general formulas (pI) to (pV). Examples of the alkali-soluble group include various groups known in this technical field.

  Specific examples include a structure in which a hydrogen atom of a carboxylic acid group, a sulfonic acid group, a phenol group, or a thiol group is substituted with a structure represented by the general formulas (pI) to (pV), preferably a carboxylic acid Group, a hydrogen atom of a sulfonic acid group is substituted with a structure represented by general formulas (pI) to (pV).

  The repeating unit having an alkali-soluble group protected with a structure represented by the general formulas (pI) to (pV) is an acid-decomposable repeating unit, and 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 one of the general formulas (pI) to (pV).

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

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

(A′2) (Meth) acrylic acid ester having lactone unit The resin (A) produced by the production method of the present invention preferably has a repeating unit of a monomer having a lactone unit, and has a lactone unit ( It is more preferable to have a repeating unit based on (meth) acrylic acid ester. As the lactone unit, any group can be used as long as it contains a lactone structure, but preferably a group containing a 5- to 7-membered ring lactone structure, and a bicyclo structure in the 5- to 7-membered ring lactone structure, Those in which other ring structures are condensed to form a spiro structure are preferred. It is more preferable to have a repeating unit having a group having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16). 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 a specific lactone structure, 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. n2 represents an integer of 0 to 4. When n2 is 2 or more, a plurality of substituents (Rb ₂ ) may be the same or different, and a plurality of substituents (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),
Rb ₀ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms. Preferred substituents that the alkyl group represented by 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. To express. A linking group represented by a single bond or —Ab ₁ —CO ₂ — is preferable. Ab ₁ represents a linear or branched alkylene group or a 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 having a structure 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.

  The content of the repeating unit having a lactone structure is preferably from 15 to 60 mol%, more preferably from 20 to 50 mol%, still more preferably from 30 to 50 mol%, based on all repeating units in the polymer.

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

  Particularly preferred repeating units having a lactone group include the following repeating units. By selecting the optimum lactone structure, the pattern profile and the density dependence become good.

  The resin (A) produced by the production method of the present invention preferably further has a repeating unit having an alicyclic hydrocarbon structure substituted with a polar group. This improves the substrate adhesion and developer compatibility. The alicyclic hydrocarbon structure of the alicyclic hydrocarbon structure substituted with a polar group is preferably an adamantyl group, a diamantyl group, or a norbornane group. The polar group is preferably a hydroxyl group or a cyano group. As the alicyclic hydrocarbon structure substituted with a preferable polar group, partial structures represented by the following general formulas (VIIa) to (VIId) are preferable.

In general formulas (VIIa) to (VIIc),
R ₂ c to R ₄ c each independently represents a hydrogen atom, a hydroxyl group or a cyano group. However, at least one of R ₂ c to R ₄ c represents a hydroxyl group or a cyano group. Preferably, one or two of R ₂ c to R ₄ c are a hydroxyl group and the rest are hydrogen atoms. In general formula (VIIa), it is more preferable that _two of R ₂ c to R ₄ c are a hydroxyl group and the remaining is a hydrogen atom.

As the repeating unit having a group represented by the general formulas (VIIa) to (VIId), at least one of R ₁₃ ′ to R ₁₆ ′ in the general formula (II-AB1) or (II-AB) 2 is Those having groups represented by general formulas (VIIa) to (VIId) (for example, R _{5 in} —COOR ₅ represents groups represented by general formulas (VIIa) to (VIId)), or the following general formula (AIIa) ) To (AIId).

In general formulas (AIIa) to (AIId),
R ₁ c represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.
R ₂ c to R ₄ c each independently represents a hydrogen atom, a hydroxyl group or a cyano group. However, at least one of R ₂ c to R ₄ c represents a hydroxyl group or a cyano group. R ₂ c to R ₄ c is a general formula (VIIa) ~ same meanings as in R ₂ c to R ₄ c to (VIIc).

  The content of the repeating unit having an alicyclic hydrocarbon structure substituted with a polar group is preferably 5 to 40 mol%, more preferably 5 to 30 mol%, still more preferably 10 to 25 mol based on all repeating units in the polymer. %.

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

  The resin (A) produced by the production method of the present invention may have a repeating unit represented by the following general formula (VIII).

In 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.
The present invention is not limited to these.

  The resin (A) produced by the production method of the present invention preferably has a repeating unit having an alkali-soluble group. Examples of the alkali-soluble group include a carboxyl group, a sulfonamide group, a sulfonylimide group, a bisulsulfonylimide group, and an aliphatic alcohol in which the α-position is substituted with an electron-withdrawing group (preferably a structure represented by the following general formula (F1) It is more preferable to have a repeating unit having a carboxyl group or a sulfonamide group.

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. All of R _{50 to} R ₅₅ are preferably fluorine atoms.

  By having a repeating unit having an alkali-soluble group, the resolution in contact hole applications is increased. The repeating unit having an alkali-soluble group 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 an alkali in the main chain of the resin through a linking group. Either a repeating unit to which a soluble group is bonded, or a polymerization initiator or chain transfer agent having an alkali-soluble group is used at the time of polymerization and introduced at the end of the polymer chain, and the linking group is monocyclic or polycyclic. It may have a cyclic hydrocarbon structure. Particularly preferred are repeating units of acrylic acid or methacrylic acid.

  As for content of the repeating unit which has an alkali-soluble group, 1-20 mol% is preferable with respect to all the repeating units in a polymer, More preferably, it is 3-15 mol%, More preferably, it is 5-10 mol%.

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

  The resin (A) produced by the production method of the present invention may further have a repeating unit that has an alicyclic hydrocarbon structure and does not exhibit acid decomposability. This can reduce the elution of low molecular components from the resist film to the immersion liquid during immersion exposure. Examples of such a repeating unit include 1-adamantyl (meth) acrylate, tricyclodecanyl (meth) acrylate, and cyclohexyl (meth) acrylate.

  The resin (A) produced by the production method of the present invention has, in addition to the above repeating structural units, dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general necessary characteristics of the resist. Various repeating structural units can be included for the purpose of adjusting the resolution, heat resistance, sensitivity, and the like.

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

Thereby, the performance required for the resin (A), in particular,
(1) Solubility in coating solvent,
(2) Film formability (glass transition point),
(3) Alkali developability,
(4) Membrane slip (hydrophobic, alkali-soluble group selection),
(5) Adhesion of unexposed part to substrate,
(6) Dry etching resistance,
Etc. can be finely adjusted.

  As such a monomer, for example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. Etc.

  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 the resin (A) produced by the production method of the present invention, the content molar ratio of each repeating structural unit is the resist dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general resist requirements. It is appropriately set in order to adjust the resolution, heat resistance, sensitivity, etc., which are performance.

The following are mentioned as a preferable aspect of resin (A) manufactured by the manufacturing method of this invention.
(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).
Those having a (meth) acrylate repeating unit preferably having a structure of (pI) to (pV).
(2) One having 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 the general formula (II-AB), a repeating unit by a maleic anhydride derivative and a repeating unit by (meth) acrylate (hybrid type).

  In the resin (A) produced by the production method of the present invention, the content of the acid-decomposable repeating unit is preferably 10 to 60 mol%, more preferably 20 to 50 mol%, still more preferably in all repeating structural units. It is 25-40 mol%.

  In the resin (A) produced by the production method of the present invention, the content of the repeating unit having a partial structure containing an alicyclic hydrocarbon represented by the general formulas (pI) to (pV) is the total repeating structural unit. 20-70 mol% is preferable, More preferably, it is 20-50 mol%, More preferably, it is 25-40 mol%.

  In the resin (A) produced by the production method of the present invention, the content of the repeating unit represented by the general formula (II-AB) is preferably 10 to 60 mol%, more preferably 15 in all repeating structural units. It is -55 mol%, More preferably, it is 20-50 mol%.

  Further, the content of the repeating structural unit based on the monomer of the further copolymer component in the resin can be appropriately set according to the performance of the desired resist. Generally, the general formula (pI) 99 mol% or less based on 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). More preferably, it is 90 mol% or less, More preferably, it is 80 mol% or less.

  When the positive photosensitive composition of the present invention is for ArF exposure, the resin preferably does not have an aromatic group from the viewpoint of transparency to ArF light.

The resin (A) produced by the production method of the present invention is preferably one in which all repeating units are composed of (meth) acrylate 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, as the resin (A) produced by the production method of the present invention, 20 to 50 mol% of a repeating unit having a partial structure containing an alicyclic hydrocarbon represented by general formulas (pI) to (pV), 20 to 50 mol% of repeating units having a lactone structure, a copolymer having 5 to 30 mol% of repeating units having an alicyclic hydrocarbon structure substituted with a polar group, or 0 to 20 mol% of other repeating units Copolymer.

Particularly preferred resins (A) include 20-50 mol% of acid-decomposable repeating units represented by the following general formulas (ARA-1) to (ARA-5), and the following general formulas (ARL-1) to (ARL- 6) Repeat unit having an alicyclic hydrocarbon structure substituted with a polar group represented by the following general formulas (ARH-1) to (ARH-3): 20-50 mol% having a lactone group represented by 6) A copolymer having 5 to 30 mol% of units, or further a repeating unit having a structure represented by a carboxyl group or general formula (F1), a repeating unit having an alicyclic hydrocarbon structure and not exhibiting acid decomposability It is a copolymer having 5 to 20 mol%.
In the formula, Rxy ₁ represents a hydrogen atom or a methyl group, and Rxa ₁ and Rxb ₁ each independently represents a methyl group or an ethyl group.

  In the case where the positive photosensitive composition of the present invention is irradiated with KrF excimer laser light, electron beam, X-ray, or high energy light beam (EUV, etc.) having a wavelength of 50 nm or less, the resin (A) is a hydroxystyrene repeating unit. An acid-decomposable resin (hereinafter also referred to as “hydroxystyrene-based acid-decomposable resin”) is preferred. The hydroxystyrene-based acid-decomposable resin is preferably a hydroxystyrene copolymer protected with a group capable of leaving by the action of hydroxystyrene / acid, a hydroxystyrene / (meth) acrylic acid tertiary alkyl ester copolymer, hydroxy Hydroxystyrene / (meth) acrylic acid tertiary alkyl ester copolymer protected with a group capable of leaving by the action of styrene / acid, hydroxystyrene / styrene copolymer protected with a group capable of leaving by the action of hydroxystyrene / acid Polymer, hydroxystyrene / (meth) acrylic acid tertiary alkyl ester / styrene copolymer, hydroxystyrene / hydroxystyrene / (meth) acrylic acid tertiary alkyl ester / styrene protected by a group capable of leaving by the action of acid A copolymer etc. can be mentioned.

  In the hydroxystyrene-based acid-decomposable resin, the content of acid-decomposable groups is determined by the number of acid-decomposable groups in the resin (B) and the number of alkali-soluble groups that are not protected by groups that are eliminated by the action of acid. With a number (S), it is expressed as B / (B + S). The content is preferably 0.01 to 0.7, more preferably 0.05 to 0.50, and still more preferably 0.05 to 0.40.

The resin (A) of the present invention can be polymerized by, for example, radical polymerization according to a conventional method. For example, as a general polymerization method, a monomer type, a thiol compound and a polymerization initiator are dissolved in a solvent, and a batch polymerization method in which polymerization is performed by heating, a solution of the monomer type, thiol compound and polymerization initiator is added to the heating solvent. Examples thereof include a dropping polymerization method which is added dropwise over 1 to 10 hours, and the dropping polymerization method is preferred. 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 the solvent used in the positive photosensitive composition of the present invention. Thereby, generation | occurrence | production of the particle at the time of a preservation | save can be suppressed.
The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon.
After the completion of the reaction, the desired resin (A) is recovered by introducing it into a solvent and recovering the powder or solid. 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 60-100 ° C.

The weight average molecular weight of the resin (A) according to the present invention is preferably 1,000 to 200,000, more preferably 3,000 to 20,000, most preferably 5, as a polystyrene conversion value by GPC method. 000 to 15,000. By setting the weight average molecular weight to 1,000 to 200,000, deterioration of heat resistance and dry etching resistance can be prevented, developability is deteriorated, and viscosity is increased, resulting in deterioration of film forming property. Can be prevented.
The molecular weight distribution is usually 1 to 5, preferably 1 to 3, more preferably 1 to 2. The smaller the molecular weight distribution, the better the resolution and the resist shape, and the smoother the side wall of the resist pattern, the better the roughness.

In the positive photosensitive composition of the present invention, the blending amount of all the resins (A) according to the present invention in the entire composition is preferably 60 to 99% by mass, more preferably 80 to 98% by mass in the total solid content. %.
In the present invention, the resin (A) may be used alone or in combination.

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

The resin (A) produced by the production method of the present invention is suitably used for a positive photosensitive composition.
Hereinafter, components other than the resin (A) of the present invention used for the positive photosensitive composition will be described.

Compound that generates acid upon irradiation with actinic rays or radiation The positive photosensitive composition of the present invention contains a compound that generates an acid upon irradiation with actinic rays or radiation (also referred to as a “photoacid generator”).
Examples of such photoacid generators include photoinitiators for photocationic polymerization, photoinitiators for photoradical polymerization, photodecolorants for dyes, photochromic agents, actinic rays used in microresists, etc. Known compounds that generate an acid upon irradiation with radiation and mixtures 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 generate an acid upon irradiation with actinic rays or radiation, compounds represented by the following general formula (ZI), (ZII) or (ZIII) can be exemplified.

In 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. An organic anion having a carbon atom is preferable.

  Preferred organic anions include organic anions represented by the following general formulas (AN1) to (AN4).

In general formulas (AN1) and (AN2):
Rc ₁ represents an organic group.

Formula (AN1) ~ (AN2), examples of the organic group in Rc _1, include those having 1 to 30 carbon atoms, preferably an alkyl group which may be substituted, cycloalkyl group, aryl group, or a mixture, A plurality are a single bond, —O—, —CO ₂ —, —S—, —SO ₃ —, —SO _2.
And a group linked by a linking group such as N (Rd ₁ ) —. Rd ₁ represents a hydrogen atom or an alkyl group, and may form a ring structure with a bonded alkyl group, cycloalkyl group, or aryl group.
More preferred as the organic group for Rc ₁ is 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. When Rc ₁ has 5 or more carbon atoms, it is preferable that at least one carbon atom has a hydrogen atom, not all hydrogen atoms are substituted with fluorine atoms, and the number of hydrogen atoms is fluorine. More preferably than atoms. By not having a perfluoroalkyl group having 5 or more carbon atoms, ecotoxicity is reduced.

As a particularly preferred embodiment of Rc ₁ , groups represented by the following general formula can be exemplified.

In the above general formula,
Rc ₆ is substituted with a perfluoroalkylene group having 4 or less carbon atoms, more preferably 2 to 4 carbon atoms, more preferably 2 to 3 carbon atoms, 1 to 4 fluorine atoms and / or 1 to 3 fluoroalkyl groups. Represents a phenylene group.
Ax represents a single bond or a divalent linking group (preferably —O—, —CO ₂ —, —S—, —SO ₃ —, —SO ₂ N (Rd ₁ ) —). Rd ₁ represents a hydrogen atom or an alkyl group, and may combine with Rc ₇ to form a ring structure.
Rc ₇ represents a hydrogen atom, a fluorine atom, a linear or branched, monocyclic or polycyclic cycloalkyl group or aryl group which may be substituted. The optionally substituted alkyl group, cycloalkyl group and aryl group preferably do not have a fluorine atom as a substituent.

In the general formulas (AN3) and (AN4),
Rc ₃ , Rc ₄ and Rc ₅ each independently represents an organic group.
Rc ₃ and Rc ₄ may combine to form a ring.

As the organic groups of Rc ₃ , Rc ₄ and Rc _{5 in} the general formulas (AN3) and (AN4),
Preferable examples are the same as the preferable organic groups in Rc ₁ .
When Rc ₃ and Rc ₄ are combined to form a ring, examples of the group formed by combining Rc ₃ and Rc ₄ include an alkylene group and an arylene group. A perfluoroalkylene group having 2 to 4 carbon atoms is preferred. By combining Rc ₃ and Rc ₄ to form a ring, the acidity of the acid generated by light irradiation is increased, and the sensitivity is improved, which is preferable.

In the general formula (ZI), the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.
Two members out of R _{201 to} R ₂₀₃ may combine to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).

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) corresponding groups.

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

  Further preferred examples of the component (Z1) 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, aryldicycloalkylsulfonium compounds, and the like.
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 linear or branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, and linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, and more preferably , An alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. 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.
The compound (ZI-2) is, R ₂₀₁ to R ₂₀₃ in formula (ZI) each independently is a compound when it represents an organic group having no aromatic ring. Here, the aromatic ring includes an aromatic ring having a hetero atom.
The aromatic ring-free organic group 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, an alkoxycarbonylmethyl group, particularly A linear or branched 2-oxoalkyl group is preferred.

The alkyl group as R ₂₀₁ to R ₂₀₃ may be linear, 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 alkyl group as R ₂₀₁ to R ₂₀₃ is
It is more preferably a linear or branched 2-oxoalkyl group or an alkoxymethyl 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 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, a pentoxy 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 ₁ c to R ₅ c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, or a halogen atom.
R ₆ c and R ₇ c 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.
R ₁ c to R ₇ Any two or more of c, and Rx and Ry may combine with 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. R ₁ c to R ₇ Any two or more of c, and as the group Rx and Ry are formed by combined include a butylene group and a pentylene group.
X ^- represents a non-nucleophilic anion, in formula (ZI) in, X ^- are those same as the.

The alkyl group as R ₁ c to R ₇ c may be either linear or branched, for example, an alkyl group having 1 to 20 carbon atoms, preferably a linear chain having 1 to 12 carbon atoms and A 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) can be exemplified.
Preferable examples of the cycloalkyl group as R ₁ c to R ₇ c include a cycloalkyl group having 3 to 8 carbon atoms (for example, a cyclopentyl group and a cyclohexyl group).
The alkoxy group as R ₁ c to R ₅ c may be linear, branched or cyclic, for example, an alkoxy group having 1 to 10 carbon atoms, preferably a linear or branched chain having 1 to 5 carbon atoms. Alkoxy groups (for example, methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group), cyclic alkoxy groups having 3 to 8 carbon atoms (for example, cyclopentyloxy group, cyclohexyl) Oxy group).
Preferably any of R ₁ c to R ₅ c is a linear or branched alkyl group, a cycloalkyl group or a linear, branched or cyclic alkoxy group, more preferably the R ₁ c to R ₅ c atoms The sum of the numbers is 2-15. Thereby, solvent solubility improves more and generation | occurrence | production of a particle is suppressed at the time of a preservation | save.

The alkyl group as Rx and Ry, there can be mentioned the same alkyl groups as R ₁ c~R ₇ c. The alkyl group as Rx and Ry is more preferably a linear or branched 2-oxoalkyl group or an alkoxymethyl group.
The cycloalkyl group as Rx and Ry may be the same as the cycloalkyl group of R ₁ c~R ₇ c. The cycloalkyl group as Rx and Ry is more 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 ₁ c to R ₇ c.
The alkoxy group in the alkoxycarbonylmethyl group may be the same as the alkoxy group as R ₁ c~R ₅ c.
Rx and Ry are preferably alkyl groups having 4 or more carbon atoms, more preferably 6 or more, and still more preferably 8 or more.

In the general formulas (ZII) and (ZIII),
R ₂₀₄ to R ₂₀₇ each independently represents an aryl group, an alkyl group or a cycloalkyl group.
The aryl group of R ₂₀₄ to R _207, a phenyl group, a naphthyl group, 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 non-nucleophilic anion as X ^{− in} formula (ZI).

  Among the compounds that generate an acid upon irradiation with actinic rays or radiation, 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, an aryl group, or an electron-withdrawing group. R ₂₀₇ is preferably an aryl group. R ₂₀₈ is preferably an electron-withdrawing group, and more preferably a cyano group or a fluoroalkyl group.
A represents an alkylene group, a cycloalkylene group, an alkenylene group or an arylene group.

Among the compounds that generate an acid upon irradiation with actinic rays or radiation, more preferred are compounds represented by the general formulas (ZI) to (ZIII), and still more preferred are compounds represented by (ZI). Even more preferred are compounds represented by (ZI-1) to (ZI-3).
Furthermore, the compound which generate | occur | produces the acid represented by the following general formula (AC1)-(AC3) by irradiation of actinic light or a radiation is preferable.

That is, as a particularly preferred embodiment of the photoacid generator, in the structure represented by the general formula (ZI), X ⁻ is an anion selected from the general formulas (AN1), (AN3), and (AN4). A compound can be mentioned.

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

  A photo-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 photoacid generator in the composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and still more preferably, based on the total solid content of the positive photosensitive composition. 1 to 7% by mass.

Resin having no group decomposable by the action of an acid The positive photosensitive composition of the present invention may contain a resin having no group decomposable by the action of an acid.
“No acid-decomposable group” means that there is no or very little decomposability due to the action of an acid in an image forming process in which the positive photosensitive composition of the present invention is usually used. It has no group that contributes to image formation by decomposition. Examples of such a resin include a resin having an alkali-soluble group and a resin having a group that is decomposed by the action of an alkali and improves the solubility in an alkali developer.
As the resin having no group capable of decomposing by the action of an acid, a resin having at least one repeating unit derived from a (meth) acrylic acid derivative and / or an alicyclic olefin derivative is preferable.
Alkali-soluble groups contained in a resin that does not have a group decomposable by the action of an acid include a carboxyl group, a phenolic hydroxyl group, an aliphatic hydroxyl group substituted at the 1- or 2-position with an electron-withdrawing group, and electron-withdrawing properties. An amino group substituted with a group (for example, a sulfonamide group, a sulfonimide group, a bissulfonylimide group), a methylene group substituted with an electron-withdrawing group, or a methine group (for example, a ketone group or an ester group). A substituted methylene group and methine group) are preferred.
The group that decomposes by the action of an alkali contained in a resin that does not have a group that decomposes by the action of an acid and increases the solubility in an alkali developer is preferably a lactone group or an acid anhydride group, more preferably Lactone group.
The resin that does not have a group capable of decomposing by the action of an acid may have a repeating unit having a functional group other than the above. As the repeating unit having another functional group, an appropriate functional group can be introduced in consideration of dry etching resistance, hydrophilicity / hydrophobicity, interaction property and the like. Other repeating units include structural units having a polar functional group such as a hydroxyl group, a cyano group, a carbonyl group, and an ester group, a repeating unit having a monocyclic or polycyclic hydrocarbon structure, a silicon atom, a halogen atom, and a fluoroalkyl. A repeating unit having a group or a repeating unit having a plurality of these functional groups.

  Although the specific example of resin which does not have the group decomposed | disassembled by the effect | action of a preferable acid is shown below, this invention is not limited to this.

  The addition amount of the resin having no group that decomposes by the action of an acid is 0 to 30% by mass, preferably 0 to 20% by mass, and more preferably 0 to 15% by mass with respect to the resin (A).

Dissolution control compound having a molecular weight of 3000 or less, having at least one selected from an alkali-soluble group, a hydrophilic group, and an acid-decomposable group. A dissolution controlling compound having a molecular weight of 3000 or less (hereinafter also referred to as “solubility controlling compound”) having at least one selected from
Examples of the dissolution control compound include a carboxyl group, a sulfonylimide group, a compound having an alkali-soluble group such as a hydroxyl group substituted at the α-position with a fluoroalkyl group, a hydroxyl group, a lactone group, a cyano group, an amide group, a pyrrolidone group, a sulfone group. A compound having a hydrophilic group such as an amide group or a compound containing a group capable of decomposing by the action of an acid to release an alkali-soluble group or a hydrophilic group is preferable. The group capable of decomposing by the action of an acid to release an alkali-soluble group or a hydrophilic group is preferably a group in which a carboxyl group or a hydroxyl group is protected with an acid-decomposable group. In order not to lower the permeability of 220 nm or less as the dissolution control compound, it is preferable to use a compound that does not contain an aromatic ring, or to use a compound having an aromatic ring in an amount of 20 wt% or less based on the solid content of the composition.
Preferred dissolution control compounds include carboxylic acid compounds having an alicyclic hydrocarbon structure such as adamantane (di) carboxylic acid, norbornane carboxylic acid, and cholic acid, or compounds in which the carboxylic acid is protected with an acid-decomposable group, and polyols such as saccharides. Or a compound having its hydroxyl group protected with an acid-decomposable group is preferred.

  The molecular weight of the dissolution controlling compound in the present invention is 3000 or less, preferably 300 to 3000, and more preferably 500 to 2500.

  The addition amount of the dissolution control compound is preferably 3 to 40% by mass, more preferably 5 to 20% by mass, based on the solid content of the positive photosensitive composition.

  Specific examples of the dissolution control compound are shown below, but the present invention is not limited thereto.

Basic Compound The positive photosensitive composition of the present invention contains a basic compound in order to reduce the change in performance over time from exposure to heating or to control the diffusibility of the acid generated by exposure in the film. Is preferred.

  Examples of basic compounds include nitrogen-containing basic compounds and onium salt compounds. Preferable nitrogen-containing basic compound structures include compounds having partial structures represented by the following general formulas (A) to (E).

In general formula (A),
R ²⁵⁰ , R ²⁵¹ and R ²⁵² are each independently a hydrogen atom, an alkyl having 1 to 20 carbons, a cycloalkyl group having 3 to 20 carbons or an aryl group having 6 to 20 carbons, wherein R ²⁵⁰ And R ²⁵¹ may combine with each other to form a ring. These may have a substituent. Examples of the alkyl group and cycloalkyl group having a substituent include an aminoalkyl group having 1 to 20 carbon atoms, an aminocycloalkyl group having 3 to 20 carbon atoms, and 1 to 1 carbon atoms. A 20 hydroxyalkyl group or a C 3-20 hydroxycycloalkyl group is preferred. These may contain an oxygen atom, a sulfur atom, or a nitrogen atom in the alkyl chain.
In general formula (E),
R ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R ²⁵⁶ each independently represent an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms.

  Preferable compounds include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, and piperidine, and may have a substituent. More preferred compounds include compounds having an imidazole structure, diazabicyclo structure, onium hydroxide structure, onium carboxylate structure, trialkylamine structure, aniline structure or pyridine structure, alkylamine derivatives having a hydroxyl group and / or an ether bond, hydroxyl groups and / or Or the aniline derivative which has an ether bond etc. can be mentioned.

  Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, benzimidazole, and the like. 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. ] Undec-7-ene. 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. The compound having an onium carboxylate structure is a compound having an onium hydroxide structure in which the anion moiety 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 aniline compounds include 2,6-diisopropylaniline and N, N-dimethylaniline. 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 based on solid content of a positive photosensitive composition, Preferably it is 0.01-5 mass%. In order to obtain a sufficient addition effect, 0.001% by mass or more is preferable, and 10% by mass or less is preferable in terms of sensitivity and developability of the non-exposed area.

Fluorine and / or silicon-based surfactant The positive photosensitive composition of the present invention further comprises a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant and silicon-based surfactant, fluorine atom and silicon atom It is preferable to contain any one of these, or two or more of them.

  When the positive photosensitive composition of the present invention contains fluorine and / or a silicon-based surfactant, adhesion and development with good sensitivity and resolution when using an exposure light source of 250 nm or less, particularly 220 nm or less. A resist pattern with few defects can be provided.

  Examples of these fluorine and / or silicon surfactants 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 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189, R08 (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.), etc. Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

  In addition to the known surfactants described above, surfactants are derived from fluoroaliphatic compounds produced by the telomerization method (also referred to as the telomer method) or the oligomerization method (also referred to as the oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.

  As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. It 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 ₆ F ₁₃ group and (poly (oxy) (Ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate) copolymer, acrylate (or methacrylate) and (poly (oxyalkylene)) acrylate having C ₈ F ₁₇ groups (or Copolymer of acrylate (or methacrylate), (poly (oxyethylene)) acrylate (or methacrylate), and (poly (oxypropylene)) acrylate (or methacrylate) having a C ₈ F ₁₇ group Coalesce, etc. Can.

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

Surface Hydrophobized Resin The positive photosensitive composition of the present invention can contain a surface hydrophobized resin.
When the resist film made of the positive resist composition of the present invention is exposed through immersion water, a surface hydrophobic resin can be further added to the positive resist composition as necessary. Thereby, the receding contact angle on the resist film surface can be improved and the immersion water followability can be improved. As the surface hydrophobizing resin, any resin can be used as long as the receding contact angle of the surface can be improved by addition, but a resin having at least one of fluorine atom and silicon atom is preferable. The addition amount can be adjusted as appropriate so that the receding contact angle of the resist film is 60 ° to 80 °, but preferably 0.1 to 5% by mass.

Organic Solvent The positive photosensitive composition of the present invention is used by dissolving the above components in a predetermined organic solvent.

  Examples of the organic solvent that can be used include ethylene dichloride, cyclohexanone, cyclopentanone, 2-heptanone, γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl. Ether acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, toluene, ethyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N, N -Dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofuran, etc.

In the present invention, the organic solvent may be used alone or in combination, but it is preferable to use a mixed solvent containing two or more solvents having different functional groups. As a result, the solubility of the material is increased, and not only the generation of particles over time can be suppressed, but also a good pattern profile can be obtained. Preferable functional groups contained in the solvent include ester groups, lactone groups, hydroxyl groups, ketone groups, and carbonate groups. As the mixed solvent having different functional groups, the following mixed solvents (S1) to (S5) are preferable.
(S1) a mixed solvent obtained by mixing a solvent containing a hydroxyl group and a solvent not containing a hydroxyl group,
(S2) a mixed solvent obtained by mixing a solvent having an ester structure and a solvent having a ketone structure;
(S3) a mixed solvent obtained by mixing a solvent having an ester structure and a solvent having a lactone structure;
(S4) a mixed solvent obtained by mixing a solvent having an ester structure, a solvent having a lactone structure, and a solvent containing a hydroxyl group;
(S5) A mixed solvent containing a solvent having an ester structure, a solvent having a carbonate structure, and a solvent having a hydroxyl group.
As a result, the generation of particles during storage of the resist solution can be reduced, and the generation of defects during application can be suppressed.

  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. And propylene glycol monomethyl ether and ethyl lactate are more preferred.

  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 more preferable, and propylene glycol monomethyl ether acetate, ethyl ethoxypropionate. 2-heptanone and cyclohexanone are particularly preferred.

Examples of the solvent having a ketone structure include cyclohexanone and 2-heptanone, and cyclohexanone is preferable.
Examples of the solvent having an ester structure include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, and butyl acetate, and propylene glycol monomethyl ether acetate is preferable.
Examples of the solvent having a lactone structure include γ-butyrolactone.
Examples of the solvent having a carbonate structure include propylene carbonate and ethylene carbonate, with propylene carbonate being 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.
The mixing ratio (mass) of the solvent having an ester structure and the solvent having a ketone structure is 1/99 to 99/1, preferably 10/90 to 90/10, and more preferably 40/60 to 80/20. . A mixed solvent containing 50% by mass or more of a solvent having an ester structure is particularly preferable from the viewpoint of coating uniformity.
The mixing ratio (mass) of the solvent having an ester structure and the solvent having a lactone structure is 70/30 to 99/1, preferably 80/20 to 99/1, and more preferably 90/10 to 99/1. . A mixed solvent containing 70% by mass or more of a solvent having an ester structure is particularly preferable from the viewpoint of stability over time. When mixing a solvent having an ester structure, a solvent having a lactone structure, and a solvent containing a hydroxyl group, the solvent having an ester structure is 30 to 80% by mass, the solvent having a lactone structure is 1 to 20% by mass, and the hydroxyl group is contained. It is preferable to contain 10-60 mass% of solvent to do.
When mixing a solvent having an ester structure, a solvent having a carbonate structure, and a solvent containing a hydroxyl group, the solvent having an ester structure is 30 to 80% by mass, the solvent having a carbonate structure is 1 to 20% by mass, and the hydroxyl group is contained. It is preferable to contain 10-60 mass% of solvent to do.

A preferable embodiment of these solvents is a solvent containing an alkylene glycol monoalkyl ether carboxylate (preferably propylene glycol monomethyl ether acetate), more preferably a mixed solvent of an alkylene glycol monoalkyl ether carboxylate and another solvent, The other solvent is at least one selected from a functional group selected from a hydroxyl group, a ketone group, a lactone group, an ester group, an ether group and a carbonate group, or a solvent having a plurality of these functional groups. A particularly preferable mixed solvent is a mixed solvent of at least one selected from ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether, butyl acetate, and cyclohexanone and propylene glycol monomethyl ether acetate.
The development defect performance can be improved by selecting an optimum solvent.

<Other additives>
The positive photosensitive composition of the present invention has further solubility in a dye, a plasticizer, a surfactant other than the fluorine and / or silicon surfactant, a photosensitizer, and a developer as necessary. A compound to be promoted and the like can be contained.

  The dissolution accelerating compound for the developer that can be used in the present invention is a low molecular weight compound having a molecular weight of 1,000 or less and having two or more phenolic OH groups or one or more carboxy groups. When it has a carboxy group, an alicyclic or aliphatic compound is preferable.

  The preferable addition amount of these dissolution promoting compounds is 2 to 50% by mass, more preferably 5 to 30% by mass with respect to the resin (A). The amount is preferably 50% by mass or less from the viewpoint of suppressing development residue and preventing pattern deformation during development.

  Such phenolic compounds having a molecular weight of 1000 or less can be obtained by referring to methods described in, for example, JP-A-4-1222938, JP-A-2-28531, U.S. Pat. No. 4,916,210, European Patent 219294, and the like. Can be easily synthesized.

  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.

  In the present invention, a surfactant other than the fluorine-based and / or silicon-based surfactant may be added. Specifically, nonionic interfaces such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan aliphatic esters, polyoxyethylene sorbitan aliphatic esters, etc. Mention may be made of activators.

  These surfactants may be added alone or in some combination.

(Pattern formation method)
The positive photosensitive 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 photosensitive 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 coater, dried, and photosensitive. A film is formed.
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.
Exposure (immersion exposure) may be performed by filling a liquid (immersion medium) having a higher refractive index than air between the photosensitive 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 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, AR-2, AR-3, AR-5 manufactured by Shipley, etc. may be used. it can.

Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, etc., but preferably far ultraviolet light having a wavelength of 250 nm or less, more preferably 220 nm or less. 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) An electron beam is preferred.

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.

EXAMPLES Next, although an Example is given and this invention is demonstrated, this invention is not limited to these Examples. In addition, the average weight molecular weight (Mw) and dispersion degree (Mw / Mn) of obtained resin (A) were calculated | required from the measurement result of the gel permeation chromatography (GPC).

Synthesis Example 1 (Synthesis of resin (RA-1))
Under a nitrogen stream, 5.7 g of cyclohexanone was placed in a three-necked flask and heated to 80 ° C. To this, 5.38 g of the following monomer (A), 1.51 g of monomer (B), 7.42 g of monomer (C), polymerization initiator (azobisisobutyronitrile (V-60): manufactured by Wako Pure Chemical Industries, Ltd.) 0 394 g of a polymerization initiator (dimethyl 2,2′-azobisisobutyrate dimethyl (V-601): manufactured by Wako Pure Chemical Industries, Ltd.) 0.553 g dissolved in 51.5 g of cyclohexanone was added dropwise over 6 hours. After completion of dropping, the reaction was further carried out at 80 ° C. for 2 hours. The reaction solution was allowed to cool and then added dropwise over 1300 m of methanol over 20 minutes. The precipitated powder was collected by filtration and dried, yielding 11.5 g of resin (RA-1). The weight average molecular weight of the obtained resin (RA-1) was 8300 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.7.

Resins (RA-2) to (RA-17) were synthesized using the same method.
In the resins (RA-1) to (RA-17), the polymerization initiator and its addition amount (mol%), the repeating unit and the composition ratio, the weight average molecular weight (Mw), and the degree of dispersion (Mw / Mn) are shown below. Table 1 shows.

Comparative Synthesis Example 1 (Synthesis of Comparative Resin (CRA-1))
Under a nitrogen stream, 5.7 g of cyclohexanone was placed in a three-necked flask and heated to 80 ° C. To this, 5.38 g of the following monomer (A), 1.51 g of monomer (B), 7.42 g of monomer (C), polymerization initiator (azobisisobutyronitrile (V-60): manufactured by Wako Pure Chemical Industries, Ltd.) 0 A solution prepared by dissolving .788 g in 51.5 g of cyclohexanone was added dropwise over 6 hours. After completion of dropping, the reaction was further carried out at 80 ° C. for 2 hours. The reaction solution was allowed to cool and then added dropwise over 1300 m of methanol over 20 minutes. The precipitated powder was collected by filtration and dried, yielding 11.9 g of resin (CRA-1). The weight average molecular weight of the obtained resin (CRA-1) was 8100 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.8.

  Table 2 below shows the relationship between chemical names and abbreviations of polymerization initiators in Table 1.

  The repeating unit and the composition ratios (A-1) to (A-12) are as follows.

Examples 1-31 and Comparative Examples 1 and 2
<Preparation of positive resist composition>
The components shown in Table 3 below and a surfactant (Troysol S-366 manufactured by Troy Chemical) 0.01 g were dissolved in a 6/4 (mass ratio) mixed solvent of propylene glycol methyl ether acetate / propylene glycol methyl ether to obtain a solid concentration of 8 A mass% solution was prepared, and this was filtered through a 0.03 m polyethylene filter to prepare a positive resist composition. The prepared positive resist composition was evaluated by the following method, and the results are shown in Table 3.

[Line edge roughness evaluation]
ARC29A manufactured by Brewer Science Co., Ltd. was uniformly applied to a silicon wafer with a spin coater at 78 nm, and heat-dried at 205 ° C. for 60 seconds to form an antireflection film. Thereafter, each positive resist composition immediately after preparation was applied by a spin coater and dried (PB) at 115 ° C. for 90 seconds to form a 170 nm resist film.
This resist film is exposed with an ArF excimer laser stepper (PAS5500 / 1100 NA = 0.75 (2/3 annular illumination) manufactured by ASML) through a mask, and immediately after exposure, heated on a hot plate at 120 ° C. for 90 seconds. (PEB). Further, the resist film was developed with an aqueous 2.38 mass% tetramethylammonium hydroxide solution at 23 ° C. for 60 seconds, rinsed with pure water for 30 seconds, and then dried to obtain a resist pattern.
Using a length-measuring scanning electron microscope (SEM), observe an isolated pattern of 120 nm, and measure the distance from the reference line where the edge in the longitudinal direction of the line pattern should be 5 μm. 50 points were measured by Hitachi, Ltd. S-8840), the standard deviation was obtained, and 3σ was calculated. A smaller value indicates better performance.

[Defect evaluation]
Each positive resist composition is directly applied on an 8-inch silicon wafer subjected to hexamethyldisilazane (HMDS) treatment using a spinner, prebaked (PAB) at 105 ° C. for 90 seconds on a hot plate, and dried. As a result, a resist film having a thickness of 220 nm was formed.
Next, an ArF excimer laser (193 nm) is selectively passed through a mask pattern (binary) using an ArF exposure apparatus NSR-S306 (manufactured by Nikon Corporation; NA (numerical aperture) = 0.78, σ = 0.30). Irradiated.
Then, PEB treatment at 110 ° C. for 90 seconds, paddle development with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 60 seconds, conditions of 1000 rotations for 1 second, and then 500 rotations for 15 seconds ( A rinsing solution was added dropwise under a forced condition such that defects are more likely to occur, and dried to form a resist pattern.
In addition, a dense hole pattern (a pattern in which hole patterns with a diameter of 300 nm are arranged at intervals of 300 nm) was formed as the pattern.
Next, the surface defect observation device KLA2351 (product name) manufactured by KLA Tencor was used to measure the number of defects in the wafer.
Similar evaluation was performed once again, and the average value of the number of defects of two wafers was obtained.

  Abbreviations in Table 3 are as follows.

  [Photoacid generator]

[Basic compounds]
TPSA: Triphenylsulfonium acetate
DIA: 2,6-diisopropylaniline
TEA: Triethanolamine
DBA: N, N-dibutylaniline
PBI: 2-phenylbenzimidazole TMEA: Tris (methoxyethoxyethyl) amine
PEA: N-phenyldiethanolamine

[Comparative resin]
CRA-2: a resin having a weight average molecular weight of 8000 and a dispersity of 1.80 produced in the same manner as in Comparative Synthesis Example 1 except that the polymerization initiator is changed to V-601.

  From the results of Table 3, it is clear that the positive resist composition of the present invention has good line edge roughness and development defects (defects) of the line pattern.

Example 32
In Synthesis Example 1, a resin (RA-18) was synthesized in the same manner as in Synthesis Example 1, except that 0.10 g of a monomer corresponding to the following repeating unit was further added. The weight average molecular weight of the resin (RA-18) was 5400, and the degree of dispersion was 1.80. Using the obtained resin (RA-18), a resist was prepared and coated in the same manner as in Example 1 to obtain a resist film. The obtained resist film was subjected to pattern exposure using pure water as an immersion liquid and an ArF excimer laser immersion stepper (Na 0.85) to form a pattern in the same manner as in Example 1. As a result, the LER was 4.9 nm. Thus, it was confirmed that the resin (RA-18) synthesized by the production method of the present invention can be suitably used for pattern formation by ArF excimer laser immersion exposure.

Example 33
Except that the resin was changed to the following resin (RA-19), resist preparation and coating were performed in the same manner as in Example 1 to obtain a resist film. However, the film thickness was 0.40 μm. The resulting resist film was exposed to a 1: 1 L / S pattern having a line width of 150 nm using a KrF excimer laser stepper (FPA3000EX-5 manufactured by Canon Inc., wavelength 248 nm), and the formation of the pattern was confirmed. As a result, LWR was 7.8 nm, and it was confirmed that the resin (RA-19) of the present invention can be suitably used for pattern formation by KrF excimer laser exposure.

Claims (5)

  When producing a resin whose alkali solubility is increased by the action of an acid by dissolving at least a monomer having an acid dissociable, dissolution inhibiting group in a polymerization solvent and polymerizing using a polymerization initiator, a polymerization initiator is used. A method for producing a resin wherein alkali solubility is increased by the action of an acid, wherein at least two types are used for polymerization.   At least (a′1) a (meth) acrylic acid ester having an acid dissociable, dissolution inhibiting group and (a′2) a (meth) acrylic acid ester having a lactone unit are dissolved in a polymerization solvent, and a polymerization initiator is added. It is characterized by polymerizing using at least two kinds of polymerization initiators when producing a resin whose alkali solubility is increased by the action of an acid, and increasing the alkali solubility by the action of an acid. The manufacturing method of resin to do.   The method for producing a resin according to claim 1, wherein the polymerization is performed by using at least one kind of a polymerization initiator having a cyano group and an initiator having an ester group as the polymerization initiator. (A) A resin produced by the production method according to any one of claims 1 to 3 and having an alkali solubility increased by the action of an acid, and (B) a photoacid generator that generates an acid upon irradiation with actinic rays or radiation. A positive photosensitive composition comprising an agent.   A pattern forming method comprising: forming a photosensitive film from the positive photosensitive composition according to claim 4; and exposing and developing the photosensitive film.