JP2009093011A - Positive resist composition and pattern forming method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive resist composition improved in pattern collapse performance and focus margin even in the formation of a fine pattern of ≤100 nm and having good exposure latitude, and a pattern forming method using the same. <P>SOLUTION: The positive resist composition comprises: (A) a resin which has an acid-decomposable repeating unit having a specific tertiary ester structure and whose solubility in an alkali developer increases by the action of an acid; (B) a compound capable of generating an acid upon irradiation with actinic rays or radiation; and (C) a compound capable of generating a compound having a proton accepting functional group of a specific structure upon irradiation with actinic rays or radiation. The pattern forming method using the same is also provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a positive resist composition whose properties change upon reaction with actinic rays or radiation, and a pattern forming method using the same. More specifically, a positive resist composition used in a semiconductor manufacturing process such as an IC, a circuit board such as a liquid crystal or a thermal head, a further photofabrication process, a lithographic printing plate, an acid curable composition, and the like. The present invention relates to the pattern forming method used.

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

  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.

  The alicyclic hydrocarbon structure is described in Patent Document 1 (Japanese Patent Laid-Open No. 2002-131897), Patent Document 2 (Japanese Patent Laid-Open No. 2003-149812), and Patent Document 3 (Japanese Patent Laid-Open No. 11-501909). As described above, norbornene skeleton and adamantane skeleton exhibiting high transparency and high dry etching resistance are used.

  In Patent Document 4 (Japanese Patent Application Laid-Open No. 2005-331918) and Patent Document 5 (Japanese Patent Application Laid-Open No. 2004-184737), in a repeating unit having an alicyclic acid-decomposable group, a spacer is interposed between the main chain and the acid-decomposable group. Various properties have been improved by introducing repeating units having a moiety.

  However, from the viewpoint of overall performance as a resist, it is actually difficult to find an appropriate combination of resin, photoacid generator, additive, solvent, etc. to be used, and the line width is 100 nm or less. When forming such fine patterns, it is extremely difficult to satisfy multiple performances such as resolution performance represented by exposure latitude and good pattern collapse performance at the same time, and improvements are required. It was.

In addition, the alicyclic skeleton generally has a low polarity, and the deprotection reactivity in the resin is greatly reduced compared to that in poly (hydroxystyrene). Therefore, a highly acidic acid is required for image formation. For example, in Patent Document 1 and Patent Document 2, a specific fluorinated organic sulfonic acid is used. Patent Document 3 describes a composition containing a photoacid generator composed of an imide anion that generates a highly acidic imide upon irradiation with actinic rays or radiation. Regarding a chemically amplified resist composition, Patent Document 6 (Japanese Patent Application Laid-Open No. 5-181263) describes a resist composition containing a specific amide compound. Patent Document 7 (Japanese Patent Laid-Open No. 2006-330098) describes a resist composition containing a compound that generates a specific aminoimidic acid.

JP 2002-131897 A JP 2003-149812 A Japanese National Patent Publication No. 11-501909 JP 2005-331918 A Japanese Patent Laid-Open No. 2004-184637 JP-A-5-181263 JP 2006-330098 A

  However, there are still many insufficient points, and improvements such as exposure latitude, focus margin, and good pattern collapse performance are required.

  An object of the present invention is to provide a positive resist composition having improved pattern collapse performance and focus margin and having good exposure latitude even in the formation of a fine pattern of 100 nm or less, and a pattern forming method using the same. There is.

  The present invention is as follows.

  (1) (A) Resin having an acid-decomposable repeating unit represented by the following general formula (I) and having increased solubility in an alkali developer by the action of an acid; (B) By irradiation with actinic rays or radiation A positive resist composition comprising a compound capable of generating an acid and (C) a compound capable of generating a compound represented by the following general formula (II) upon irradiation with actinic rays or radiation.

In general formula (I),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
Ry _{1 to} Ry ₃ each independently represents an alkyl group or a cycloalkyl group. At least two members out of Ry _{1 to} Ry ₃ may be bonded to form a ring structure.
Z represents a divalent linking group.

In general formula (II):
Q ₁ and Q ₂ each independently represents a monovalent organic group. However, either Q ₁ or Q ₂ has a proton acceptor functional group. Q ₁ and Q ₂ may combine to form a ring, and the formed ring may have a proton acceptor functional group.
X ₁ and X ₂ each independently represent —CO— or —SO ₂ —.

  (2) The positive resist composition as described in (1), wherein in the general formula (I), Z is a divalent chain hydrocarbon group or a divalent cyclic hydrocarbon group.

  (3) The positive resist composition as described in (1) or (2), wherein the compound represented by the general formula (II) is represented by the following general formula (III).

In general formula (III):
Q ₁ and Q ₃ each independently represents a monovalent organic group. However, _one of Q ₁ and Q ₃ has a proton acceptor functional group. Q ₁ and Q ₃ may combine to form a ring, and the formed ring may have a proton acceptor functional group.
X ₁ , X ₂ and X ₃ each independently represent —CO— or —SO ₂ —.
A represents a divalent linking group.
B represents a single bond, an oxygen atom, or —N (Qx) —.
Qx represents a hydrogen atom or a monovalent organic group.
When B is —N (Qx) —, Q ₃ and Qx may combine to form a ring.
n represents 0 or 1.

  (4) The compound that generates the compound represented by the general formula (II) or the general formula (III) upon irradiation with actinic rays or radiation is a sulfonium compound represented by the general formula (II) or the general formula (III). The positive resist composition as described in any one of (1) to (3), which is a salt or an iodonium salt of a compound represented by the general formula (II) or the general formula (III).

  (5) A pattern forming method comprising a step of forming a film from the positive resist composition according to any one of (1) to (4), exposing the film, and developing the film.

  According to the present invention, it is possible to provide a positive resist composition having improved pattern collapse, improved focus margin and good exposure latitude even in the formation of a fine pattern of 100 nm or less, and a pattern forming method using the same. .

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

(A) Resin whose solubility in an alkaline developer is increased by the action of an acid The resin whose solubility in an alkaline developer is increased by the action of an acid used in the positive resist composition of the present invention is represented by the following general formula (I ) Represented by the general formula (1)) (hereinafter also referred to as “resin of component (A)”).

In general formula (I),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
Ry _{1 to} Ry ₃ each independently represents an alkyl group or a cycloalkyl group. At least two members out of Ry _{1 to} Ry ₃ may be bonded to form a monocyclic or polycyclic hydrocarbon structure.
Z represents a divalent linking group.

In general formula (I), the alkyl group of Xa ₁ is preferably an alkyl group having 1 to 5 carbon atoms, and examples thereof include a methyl group and an ethyl group. The alkyl group of Xa ₁ may be substituted with a hydroxyl group, a halogen atom or the like.
Xa ₁ is preferably a hydrogen atom or a methyl group.
The alkyl group of Ry _{1 to} Ry ₃ may be either a linear alkyl group or a branched alkyl group, and may have a substituent. Preferred linear and branched alkyl groups have 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms, and include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and t-butyl groups. And preferably a methyl group or an ethyl group.
The cycloalkyl group of Ry ₁ to Ry _3, for example, a monocyclic cycloalkyl group having 3 to 8 carbon atoms may be a cycloalkyl group polycyclic 7-14 carbon atoms, optionally substituted Also good. Preferred examples of the monocyclic cycloalkyl group include a cyclopentyl group, a cyclohexyl group, and a cyclopropyl group. Preferred examples of the polycyclic cycloalkyl group include an adamantyl group, a norbornane group, a tetracyclododecanyl group, a tricyclodecanyl group, and a diamantyl group.

As the monocyclic hydrocarbon structure formed by combining at least two members out of Ry _{1 to} Ry ₃ , a cyclopentyl group and a cyclohexyl group are preferable. As the polycyclic hydrocarbon structure formed by bonding at least two of Ry _{1 to} Ry ₃ , an adamantyl group, a norbornyl group, and a tetracyclododecanyl group are preferable.
Z is preferably a divalent linking group having 1 to 20 carbon atoms, more preferably a divalent chain hydrocarbon group having 1 to 20 carbon atoms, or a divalent cyclic hydrocarbon group having 3 to 20 carbon atoms. Even more preferably, it is a group in which a chain alkylene group having 1 to 4 carbon atoms, a cyclic alkylene group having 5 to 20 carbon atoms or a chain alkylene group, a cyclic alkylene group, an oxy group, a carbonyl group and the like are combined.
Examples of the chain alkylene group having 1 to 4 carbon atoms include a methylene group, an ethylene group, a propylene group, and a butylene group, which may be linear or branched. A methylene group is preferred.
Examples of the cyclic alkylene group having 5 to 20 carbon atoms include monocyclic cyclic alkylene groups such as cyclopentylene group and cyclohexylene group, and polycyclic cyclic alkylene groups such as norbornylene group and adamantylene group. An adamantylene group is preferred.

  The polymerizable compound for forming the repeating unit represented by the general formula (I) can be easily synthesized by a known method. For example, using a method similar to the method described in JP-A-2005-331918, as shown in the following formula, an alcohol and a carboxylic acid halide compound are reacted under basic conditions, and then this and a carboxylic acid compound are converted into a base. It can be synthesized by reacting under sexual conditions.

  Preferred specific examples of the repeating unit represented by formula (I) are shown below, but the present invention is not limited thereto.

  The repeating unit represented by the general formula (I) is decomposed by the action of an acid to generate a carboxyl group, and the solubility in an alkali developer increases.

In addition to the acid-decomposable repeating unit represented by the general formula (I), the resin as the component (A) may further have a repeating unit having another acid-decomposable group.
The repeating unit having another acid-decomposable group other than the acid-decomposable repeating unit represented by the general formula (I) is preferably a repeating unit represented by the following general formula (IV).

In general formula (IV),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom, and is the same as Xa ₁ in the general formula (I).
Rx _{1 to} Rx ₃ each independently represents an alkyl group or a cycloalkyl group. At least two of Rx _{1 to} Rx ₃ may be bonded to form a cycloalkyl group.

The alkyl group of Rx _{1 to} Rx ₃ is linear or branched having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and t-butyl group. The shape is preferred.
The cycloalkyl group rx ₁ to Rx _3, cyclopentyl group, a monocyclic cycloalkyl group having 3 to 8 carbon atoms such as a cyclohexyl group, a norbornyl group, tetra tricyclodecanyl group, tetracyclododecanyl group, adamantyl group And a polycyclic cycloalkyl group having 7 to 14 carbon atoms is preferred.
At least two rx ₁ to Rx ₃ is formed by bonding, the cycloalkyl group, a cyclopentyl group, a monocyclic cycloalkyl group having 3 to 8 carbon atoms such as a cyclohexyl group, a norbornyl group, tetra tricyclodecanyl group And a polycyclic cycloalkyl group having 7 to 14 carbon atoms such as a tetracyclododecanyl group and an adamantyl group.
It is preferable that Rx ₁ is a methyl group or an ethyl group, and Rx ₂ and Rx ₃ are bonded to each other to bond the above monocyclic or polycyclic cycloalkyl group.

  The repeating unit represented by the general formula (IV) is decomposed by the action of an acid to generate a carboxyl group, and the solubility in an alkali developer is increased.

  Although the specific example of the repeating unit which has a preferable acid-decomposable group is shown below, this invention is not limited to this.

  Preferred repeating units represented by the general formula (IV) are 1, 2, 10, 11, 12, 13, and 14 repeating units in the above specific examples.

  When the acid-decomposable repeating unit represented by the general formula (I) and a repeating unit having another acid-decomposable group (preferably a repeating unit represented by the general formula (IV)) are used in combination, the general formula ( The ratio of the acid-decomposable repeating unit represented by I) and the repeating unit having another acid-decomposable group is preferably 90:10 to 10:90, more preferably 80:20 to 20 in terms of molar ratio. : 80.

  (A) As for content of the repeating unit which has all the acid-decomposable groups in resin of a component, 20-50 mol% is preferable with respect to all the repeating units in a polymer, More preferably, it is 25-45 mol%.

  The resin of component (A) preferably further has a repeating unit having at least one group selected from a lactone group, a hydroxyl group, a cyano group, and an alkali-soluble group.

The resin of component (A) preferably has a repeating unit having a lactone structure.
Any lactone structure can be used as long as it has a lactone structure, but a 5- to 7-membered lactone structure is preferable, and a bicyclo structure or a spiro structure is formed in the 5- to 7-membered ring lactone structure. The other ring structure is preferably condensed. It is more preferable to have a repeating unit having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16). The lactone structure may be directly bonded to the main chain. Preferred lactone structures are those represented by the general formulas (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), and (LC1-14). Yes, 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. More preferably, they are a C1-C4 alkyl group, a cyano group, and an acid-decomposable group. 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.

  Examples of the repeating unit having a lactone structure represented by any one of the general formulas (LC1-1) to (LC1-16) include 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 (preferably 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, or a divalent linking group obtained by combining these. Preferably a single bond, -Ab ₁ -CO ₂ - is a divalent linking group represented by. Ab ₁ is a linear or branched alkylene group or a monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group or a norbornylene 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 lactone structure are given below, but the present invention is not limited thereto.

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

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

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 remaining is a hydrogen atom. In general formula (VIIa), more preferably, _two of R ₂ c to R ₄ c are hydroxyl groups and the remaining are hydrogen atoms.

  Examples of the repeating unit having a partial structure represented by the general formulas (VIIa) to (VIId) include the repeating units represented by the following general formulas (AIIa) to (AIId).

In the general formulas (AIIa) to (AIIb),
R ₁ c represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.
R ₂ c to R ₄ c are in the general formula (VIIa) ~ (VIIc), same meanings as R ₂ c~R ₄ c.

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

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

  The resin of component (A) 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 (for example, hexafluoroisopropanol group) substituted with an electron-attracting group at the α-position. It is more preferable to have a repeating unit. 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 and 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.

  As the repeating unit having at least one group selected from a lactone group, a hydroxyl group, a cyano group and an alkali-soluble group, more preferably, a repeating unit having at least two groups selected from a lactone group, a hydroxyl group, a cyano group and an alkali-soluble group Preferably, it is a repeating unit having a cyano group and a lactone group. Particularly preferred is a repeating unit having a structure in which a cyano group is substituted on the lactone structure of the above general formula (LCI-4).

The resin of component (A) 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 a repeating unit of 1-adamantyl (meth) acrylate, diamantyl (meth) acrylate, tricyclodecanyl (meth) acrylate, and cyclohexyl (meth) acrylate.

  In addition to the above repeating structural unit, the resin of component (A) includes dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general required properties of resist, such as resolution, heat resistance, and sensitivity. It can have various repeating units for the purpose of adjusting the.

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

Thereby, the performance required for the resin of component (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 units may be copolymerized.

  In the resin of component (A), the molar ratio of each repeating structural unit is the resist dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general resist performance required for resolving power and heat resistance. In order to adjust the sensitivity and the like, it is set as appropriate.

  When the positive photosensitive composition of the present invention is for ArF exposure, the resin of component (A) preferably has no aromatic group from the viewpoint of transparency to ArF light.

  As the resin of component (A), preferably, all of the repeating units are composed of (meth) acrylate-based repeating units. In this case, all of the repeating units are methacrylate repeating units, all of the repeating units are acrylate repeating units, or all of the repeating units are methacrylate repeating units and acrylate repeating units. Although it can be used, the acrylate-based repeating unit is preferably 50 mol% or less of the total repeating units. More preferably, the (meth) acrylate repeating unit having an acid-decomposable group represented by the general formula (I) is 20 to 50 mol%, the (meth) acrylate repeating unit having a lactone structure is 20 to 50 mol%, It is a copolymer having 5 to 30 mol% of (meth) acrylate-based repeating units having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group, and further containing 0 to 20 mol% of other (meth) acrylate-based repeating units. .

The resin of component (A) can be synthesized by, for example, radical polymerization according to a conventional method. For example, as a general synthesis method, a monomer type and a polymerization initiator are dissolved in a solvent, and a batch polymerization method in which polymerization is carried out by heating.
Examples include a dropping polymerization method that is added dropwise over 0 hours, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, the polymerization is performed using the same solvent as the solvent used in the positive resist composition of the present invention. Thereby, the generation of particles during storage can be suppressed.
The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. If desired, a polymerization initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery. The concentration of the reaction is 5 to 50% by mass, preferably 10 to 30% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.
The weight average molecular weight of the component (A) resin is preferably from 1,000 to 200,000, more preferably from 3,000 to 20,000, and most preferably from 5,000 to 200 in terms of polystyrene by GPC method. 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 degree of dispersion (molecular weight distribution) is usually from 1 to 5, preferably from 1 to 3, more preferably from 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.

  When the resin of component (A) is used for a positive resist composition that irradiates KrF excimer laser light, electron beam, X-ray, high energy light (EUV, etc.) having a wavelength of 50 nm or less, resin of component (A) Preferably has a repeating unit of the general formula (I) and a repeating unit having a hydroxystyrene structure. Examples of the repeating unit having a hydroxystyrene structure include o-, m-, p-hydroxystyrene and / or hydroxystyrene protected with an acid-decomposable group. The hydroxystyrene repeating unit protected with an acid-decomposable group is preferably 1-alkoxyethoxystyrene or t-butylcarbonyloxystyrene. In addition to the repeating unit represented by the general formula (I) and the repeating unit having a hydroxystyrene structure, it may further have a repeating unit represented by the general formula (IV).

Specific examples of the resin having a repeating unit having a hydroxystyrene structure and a repeating unit represented by formula (I) used in the present invention are shown below, but the present invention is not limited thereto. In specific examples, Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.

In the positive resist composition of the present invention, the blending amount of the resin as the component (A) in the whole composition is preferably 50 to 99.99% by mass, more preferably 60 to 99.0% by mass in the total solid content. It is.
In the present invention, the resin of component (A) may be used alone or in combination.

(B) Compound that generates an acid upon irradiation with actinic rays or radiation A compound that generates an acid upon irradiation with actinic rays or radiation (hereinafter referred to as “acid generator”) used in the positive resist composition of the present invention. Is described below.
The acid generator used in the present invention can be selected from compounds generally used as an acid generator.
In other words, photoinitiators for photocationic polymerization, photoinitiators for radical photopolymerization, photodecolorants for dyes, photochromic agents, or active rays or radiations such as far ultraviolet rays and X-rays used in micro resists, etc. A known compound that generates an acid by irradiation and a mixture thereof can be appropriately selected and used.

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

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, such as US Pat. No. 3,849,137,
German Patent No. 3914407, JP-A-63-26653, JP-A-55-164824, JP-A-62-69263, JP-A-63-146038, JP-A-63-163452, JP-A-63-163452. The compounds described in JP-A-62-153853 and 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.

  Preferred compounds among the acid generators include compounds represented by the following general formulas (ZI), (ZII), and (ZIII).

In general formula (ZI),
R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
X ⁻ represents a non-nucleophilic anion.

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

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

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

The compound (ZI-1) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (ZI), arylsulfonium compound, i.e., a compound having arylsulfonium as a cation.

In the arylsulfonium compound, all of R _{201 to} R ₂₀₃ may be an aryl group, or a part of R _{201 to} R ₂₀₃ may be an aryl group, and the rest may be 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 a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure having an oxygen atom, a nitrogen atom, a sulfur atom or the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue (a group formed by losing one hydrogen atom from pyrrole) and a furan residue (a group formed by losing one hydrogen atom from furan). Groups), thiophene residues (groups formed by the loss of one hydrogen atom from thiophene), indole residues (groups formed by the loss of one hydrogen atom from indole), benzofuran residues ( A group formed by losing one hydrogen atom from benzofuran), a benzothiophene residue (a group formed by losing one hydrogen atom from benzothiophene), and the like. 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 (e.g., having from 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, a phenylthio group, or the like, as a substituent. Preferred substituents are linear or branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, and alkoxy groups having 1 to 12 carbon atoms, most preferably alkyl having 1 to 4 carbon atoms. Group, 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.

Examples of the non-nucleophilic anion as X ⁻ include a sulfonate anion, a carboxylate anion, a sulfonylimide anion, a bis (alkylsulfonyl) imide anion, and a tris (alkylsulfonyl) methyl anion.

  A non-nucleophilic anion is an anion that has an extremely low ability to cause a nucleophilic reaction, and is an anion that can suppress degradation over time due to an intramolecular nucleophilic reaction. This improves the temporal stability of the resist.

  Examples of the sulfonate anion include an aliphatic sulfonate anion, an aromatic sulfonate anion, and a camphor sulfonate anion.

  Examples of the carboxylate anion include an aliphatic carboxylate anion, an aromatic carboxylate anion, and an aralkylcarboxylate anion.

  Examples of the aliphatic group in the aliphatic sulfonate anion include, for example, an alkyl group having 1 to 30 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, sec- Butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl And an eicosyl group and a cycloalkyl group having 3 to 30 carbon atoms, specifically, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, a norbornyl group, a boronyl group, and the like.

  The aromatic group in the aromatic sulfonate anion is preferably an aryl group having 6 to 14 carbon atoms, such as a phenyl group, a tolyl group, and a naphthyl group.

  The alkyl group, cycloalkyl group, and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion may have a substituent.

  Examples of such substituents include nitro groups, halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, iodine atoms), carboxyl groups, hydroxyl groups, amino groups, cyano groups, and alkoxy groups (preferably having 1 to 5 carbon atoms). ), A cycloalkyl group (preferably 3 to 15 carbon atoms), an aryl group (preferably 6 to 14 carbon atoms), an alkoxycarbonyl group (preferably 2 to 7 carbon atoms), an acyl group (preferably 2 to 12 carbon atoms). ), An alkoxycarbonyloxy group (preferably having 2 to 7 carbon atoms), an alkylthio group (preferably having 1 to 15 carbon atoms), and the like. About the aryl group and ring structure which each group has, an alkyl group (preferably C1-C15) can further be mentioned as a substituent.

  Examples of the aliphatic group in the aliphatic carboxylate anion include the same aliphatic groups as in the aliphatic sulfonate anion.

  Examples of the aromatic group in the aromatic carboxylate anion include the same aromatic groups as in the aromatic sulfonate anion.

  The aralkyl group in the aralkyl carboxylate anion is preferably an aralkyl group having 6 to 12 carbon atoms, such as a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group, and a naphthylmethyl group.

  The aliphatic group, aromatic group and aralkyl group in the aliphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion may have a substituent. Examples of the substituent include aliphatic sulfonic acid The same halogen atom, alkyl group, cycloalkyl group, alkoxy group, alkylthio group and the like as in the anion can be exemplified.

  Examples of the sulfonylimide anion include saccharin anion.

  The alkyl group in the bis (alkylsulfonyl) imide anion and tris (alkylsulfonyl) methyl anion is preferably an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, An isobutyl group, a sec-butyl group, a pentyl group, a neopentyl group, and the like can be given. These alkyl groups may have a substituent, and examples of the substituent include a halogen atom, an alkyl group substituted with a halogen atom, an alkoxy group, an alkylthio group, and the like, which are substituted with a fluorine atom. Alkyl groups are preferred.

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

Examples of the non-nucleophilic anion of X ⁻ include an aliphatic sulfonate anion in which the α-position of the sulfonic acid is substituted with a fluorine atom, an aromatic sulfonate anion substituted with a fluorine atom or a group having a fluorine atom, and an alkyl group. A bis (alkylsulfonyl) imide anion substituted with a fluorine atom and a tris (alkylsulfonyl) methide anion wherein an alkyl group is substituted with a fluorine atom are preferred. The non-nucleophilic anion is particularly preferably a perfluoroaliphatic sulfonate anion having 4 to 8 carbon atoms, an aromatic sulfonate anion having a fluorine atom, particularly preferably a nonafluorobutane sulfonate anion, a perfluorooctane sulfonate anion, It is a pentafluorobenzenesulfonic acid anion and 3,5-bis (trifluoromethyl) benzenesulfonic acid anion.

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 containing 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, or an alkoxycarbonylmethyl group, particularly preferably Is a linear, branched 2-oxoalkyl group.

The alkyl group as R _{201 to} R ₂₀₃ may be either linear or branched, and is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, or a propyl group. Butyl group, pentyl group and the like. More preferable examples of the alkyl group include a 2-linear or branched oxoalkyl group and an alkoxycarbonylmethyl group.

The cycloalkyl group as R ₂₀₁ to R ₂₀₃ is preferably a cycloalkyl group having 3 to 10 carbon atoms, e.g., cyclopentyl, cyclohexyl group and a norbornyl group. More preferred examples of the cycloalkyl group include a 2-oxocycloalkyl group.

  The 2-oxoalkyl group may be linear, branched or cyclic, and preferably includes a group having> C═O at the 2-position of the above alkyl group or cycloalkyl group.

  The alkoxy group in the alkoxycarbonylmethyl group is preferably an alkoxy group having 1 to 5 carbon atoms (methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group).

R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

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

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

In the general formula (ZI-3), the alkyl group as R _{1c to} R _7c is preferably a linear or branched alkyl group having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, a linear group, or A branched propyl group, a linear or branched butyl group, a linear or branched pentyl group and the like can be mentioned.
The cycloalkyl group as R _{1c to} R _7c is preferably a cycloalkyl group having 3 to 8 carbon atoms, and examples thereof include a cyclopentyl group and a cyclohexyl group.
The alkoxy group as R _1c to R _5c may be linear, branched, or cyclic, e.g., an alkoxy group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms linear or branched alkoxy Group (for example, methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group), cyclic alkoxy group having 3 to 8 carbon atoms (for example, cyclopentyloxy group, cyclohexyloxy) Group).
Preferably any one of R _{1c to} R _5c is a linear or branched alkyl group, a cycloalkyl group, or a linear, branched or cyclic alkoxy group, and more preferably the sum of the carbon number of R _{1c to} R _5c is 2-15. Thereby, solvent solubility improves more and generation | occurrence | production of a particle is suppressed at the time of a preservation | save.

_Examples of the alkyl group and cycloalkyl group as R _x and R _y include the same alkyl groups and cycloalkyl groups as R _{1c to} R _{7c, such} as a 2-oxoalkyl group and a 2-oxocycloalkyl group. An alkoxycarbonylmethyl group is more preferable.
Examples of the 2-oxoalkyl group and 2-oxocycloalkyl group include a group having> C═O at the 2-position of the alkyl group or cycloalkyl group as R _{1c to} R _7c .
Examples of the alkoxy group in the alkoxycarbonylmethyl group include the same alkoxy groups as R _{1c to} R _5c .
R _x and R _y are preferably an alkyl group having 4 or more carbon atoms, more preferably 6 or more, and still more preferably 8 or more.

In the general formulas (ZII) and (ZIII),
R ₂₀₄ to R ₂₀₇ each independently represents an aryl group, an alkyl group or a cycloalkyl group.
X ^- represents a non-nucleophilic anion, in formula (ZI) in, X ^- are those same as the.

Formula (ZII), a phenyl group, a naphthyl group preferably as in, aryl group R ₂₀₄ to R ₂₀₇ in (ZIII), more preferably a phenyl group. Aryl group R ₂₀₄ to R ₂₀₇ represents an oxygen atom, a nitrogen atom, may be an aryl group having a heterocyclic structure having a sulfur atom and the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue (a group formed by losing one hydrogen atom from pyrrole) and a furan residue (a group formed by losing one hydrogen atom from furan). Groups), thiophene residues (groups formed by the loss of one hydrogen atom from thiophene), indole residues (groups formed by the loss of one hydrogen atom from indole), benzofuran residues ( A group formed by losing one hydrogen atom from benzofuran), a benzothiophene residue (a group formed by losing one hydrogen atom from benzothiophene), and the like.
The alkyl group as R ₂₀₄ to R ₂₀₇ is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group.
The cycloalkyl group as R ₂₀₄ to R ₂₀₇ is preferably a cycloalkyl group having 3 to 10 carbon atoms, e.g., cyclopentyl, cyclohexyl group and a norbornyl group.
The R ₂₀₄ to R ₂₀₇ are substituents which may have, for example, an alkyl group (for example, 1 to 15 carbon atoms), 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.

  Preferred examples of the acid generator include compounds represented by the following general formulas (ZIV), (ZV), and (ZVI).

In the general formula (ZIV), Ar ₃ each independently represents an aryl group.
In the general formulas (ZV) and (ZVI), R ₂₀₈ each independently represents an alkyl group, a cycloalkyl group, or an aryl group.
A represents an alkylene group, an alkenylene group or an arylene group.

  Among the acid generators, compounds represented by the general formulas (ZI) to (ZIII) are more preferable.

As the acid generator in the present invention, particularly preferably, an anion structure containing an alkyl group having 4 or less carbon atoms substituted with a fluorine atom, a cycloalkyl group substituted with a fluorine atom, or an aromatic group substituted with a fluorine atom; An acid generator having a triarylsulfonium cation structure. Such acid generators are preferably those represented by the following general formulas (B1) to (B3).

In the general formulas (B1) to (B3),
R ₁ represents an alkyl group, an alicyclic hydrocarbon group, a hydroxyl group, a carboxyl group, an alkoxy group or a halogen atom.
y represents 0 or an integer of 1 to 5 independently of each other. When y is an integer of 2 or more, two or more R _{1 s} may be the same or different.
Q _{1 to} Q ₄ are each independently an alkyl group having 1 to 8 carbon atoms substituted with a fluorine atom, a cycloalkyl group substituted with a fluorine atom, an aryl group substituted with a fluorine atom, or a fluorinated alkyl group. Represents a substituted aryl group.

As the alkyl group for R ₁ , a linear or branched alkyl group having 1 to 15 carbon atoms is preferable, and examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, and a t-butyl group. Can be mentioned.
The alicyclic hydrocarbon group for R ₁ is preferably a cycloalkyl group having 3 to 15 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, and the like.
The alkyl group substituted with a fluorine atom Q ₁ to Q _4, for _{example, -CF 3, -C 2 F 5} , -n-C 3 F 7, -n-C 4 F 9, -n-C 8 _{F 17, -CF (CF 3)} 2, -CH (CF 3) 2, - (CF 2) 2 OCF 2 CF 3, - (CF 2) 2 O (CH 2) 3 CH 3, - (CF 2) _{2 O (CH 2) 13 CH} 3, - (CF 2) 2 O (CF 2) 2 (CH 2) 3 CH 3 and the like. The alkyl group having 4 or less carbon atoms substituted with a fluorine atom of Q _{1 to} Q ₄ may further have a substituent such as an alkoxy group or a fluoroalkoxy group.
Examples of the aryl group substituted with a fluorine atom of Q _{1 to} Q ₄ include 2,3,4,5,6-pentafluorophenyl group, 2,3,4-trifluorophenyl group, and 2,4-difluoro. A phenyl group, 4-fluorophenyl group, 4-undecanyloxy-2,3,5,6-tetrafluorophenyl group and the like can be mentioned.
Examples of the aryl group substituted with a fluorinated alkyl group of Q _{1 to} Q ₄ include a 3-trifluoromethylphenyl group, a 3,5-bis (trifluoromethyl) phenyl group, a 4-trifluoromethylphenyl group, And 4-n-nonafluorobutylphenyl group.
In particular, in the general formula (B2), Q ₂ and Q _{3 which} are bonded to form a ring structure are preferable from the viewpoint of improving exposure latitude.

  Examples of particularly preferable acid generators are given below.

An acid generator can be used individually by 1 type or in combination of 2 or more types.
The content of the acid generator in the positive resist composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, based on the total solid content of the positive resist composition. Preferably it is 1-7 mass%.

(C) Compound that generates compound represented by general formula (II) upon irradiation with actinic ray or radiation The positive resist composition of the present invention is represented by the following general formula (II) upon irradiation with actinic ray or radiation. A compound that generates a compound (hereinafter also referred to as “compound (C)”).

In general formula (II):
Q ₁ and Q ₂ each independently represents a monovalent organic group. However, either Q ₁ or Q ₂ has a proton acceptor functional group. Q ₁ and Q ₂ may combine to form a ring, and the formed ring may have a proton acceptor functional group.
X ₁ and X ₂ each independently represent —CO— or —SO ₂ —.

The monovalent organic group as Q ₁ and Q _{2 in the} general formula (II) preferably has 1 to 40 carbon atoms, such as an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and an alkenyl group. And so on.

The alkyl group in Q ₁ and Q ₂ may further have a substituent, preferably a linear or branched alkyl group having 1 to 30 carbon atoms, and an oxygen atom, sulfur atom, nitrogen in the alkyl chain You may have an atom. Specifically, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-dodecyl group, n-tetradecyl group, n-octadecyl group, etc. And a branched alkyl group such as isopropyl group, isopropyl group, isobutyl group, t-butyl group, neopentyl group, 2-ethylhexyl group.
The cycloalkyl group in Q ₁ and Q ₂ may further have a substituent, preferably a cycloalkyl group having 3 to 20 carbon atoms, and has an oxygen atom and a nitrogen atom in the ring. Also good. Specific examples include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, and the like.
The aryl group in Q ₁ and Q ₂ may further have a substituent, preferably an aryl group having 6 to 14 carbon atoms, and examples thereof include a phenyl group and a naphthyl group.
The aralkyl group in Q ₁ and Q ₂ may further have a substituent, and preferably an aralkyl group having 7 to 20 carbon atoms, such as benzyl group, phenethyl group, naphthylmethyl group, naphthylethyl. Groups.
The alkenyl group in Q ₁ and Q ₂ may further have a substituent, and examples thereof include a group having a double bond at an arbitrary position of the alkyl group.
Examples of further substituents that each of the above groups may have include, for example, a halogen atom, a hydroxyl group, a nitro group, a cyano group, a carboxy group, a carbonyl group, a cycloalkyl group (preferably having 3 to 10 carbon atoms), and an aryl group. (Preferably 6 to 14 carbon atoms), alkoxy group (preferably 1 to 10 carbon atoms), acyl group (preferably 2 to 20 carbon atoms), acyloxy group (preferably 2 to 10 carbon atoms), alkoxycarbonyl group ( Preferably, it has 2 to 20 carbon atoms, and an aminoacyl group (preferably 2 to 10 carbon atoms).
As for the cyclic structure in the aryl group, cycloalkyl group and the like, examples of the substituent further include an alkyl group (preferably having 1 to 10 carbon atoms). As for the aminoacyl group, examples of the substituent further include an alkyl group (preferably having a carbon number of 1 to 10). Examples of the alkyl group having a substituent include perfluoroalkyl groups such as a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, and a perfluorobutyl group.

One of the monovalent organic groups of Q ₁ and Q ₂ has a proton acceptor functional group. The proton acceptor functional group is a group that can electrostatically interact with a proton or a functional group having a lone pair of electrons, such as a functional group having a macrocyclic structure such as a cyclic polyether, or π A functional group having a nitrogen atom having a lone electron pair with little conjugation contribution can be given. Examples of the nitrogen atom having a lone electron pair with little contribution of π conjugation include a nitrogen atom having a partial structure represented by the following general formula.

Preferable partial structures of the proton acceptor functional group include, for example, crown ether, azacrown ether, tertiary amine, secondary amine, primary amine, pyridine, imidazole, pyrazine, aniline structure and the like. The number of carbon atoms is preferably 4 to 30, and examples of the group having such a structure include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and an alkenyl group. The alkyl group, cycloalkyl group, aryl group, aralkyl group and alkenyl group are the same as those mentioned above.
These groups may further have a substituent.

  Examples of further substituents that each of the above groups may have include, for example, a halogen atom, a hydroxyl group, a nitro group, a cyano group, a carboxy group, a carbonyl group, a cycloalkyl group (preferably having 3 to 10 carbon atoms), and an aryl group. (Preferably 6 to 14 carbon atoms), alkoxy group (preferably 1 to 10 carbon atoms), acyl group (preferably 2 to 20 carbon atoms), acyloxy group (preferably 2 to 10 carbon atoms), alkoxycarbonyl group ( Preferably, it has 2 to 20 carbon atoms, and an aminoacyl group (preferably 2 to 20 carbon atoms). As for the cyclic structure in the aryl group, cycloalkyl group and the like, examples of the substituent further include an alkyl group (preferably having a carbon number of 1 to 20). As for the aminoacyl group, examples of the substituent further include an alkyl group (preferably having 1 to 20 carbon atoms).

The proton acceptor functional group may be substituted with an organic group having a bond that is cleaved by an acid. Examples of the organic group having a bond that can be cleaved by an acid include an amide group, an ester group (preferably a tertiary alkyloxycarbonyl group), an acetal group (preferably a 1-alkyloxy-alkyloxy group), and carbamoyl. Group, carbonate group and the like.
Examples of the structure in which Q ₁ and Q ₂ are bonded to form a ring and the formed ring has a proton acceptor functional group include, for example, an organic group of Q ₁ and Q ₂ is further an alkylene group, an oxy group And a structure bonded with an imino group or the like.

In the general formula (II), it is preferable that at least one of X ₁ and X ₂ is —SO ₂ —.

  The compound represented by the general formula (II) is preferably represented by the following general formula (III).

In general formula (III):
Q ₁ and Q ₃ each independently represents a monovalent organic group. However, _one of Q ₁ and Q ₃ has a proton acceptor functional group. Q ₁ and Q ₃ may combine to form a ring, and the formed ring may have a proton acceptor functional group.
X ₁ , X ₂ and X ₃ each independently represent —CO— or —SO ₂ —.
A represents a divalent linking group.
B represents a single bond, an oxygen atom, or —N (Qx) —.
Qx represents a hydrogen atom or a monovalent organic group.
When B is —N (Qx) —, Q ₃ and Qx may combine to form a ring.
n represents 0 or 1.

In formula (III), Q ₁ has the same meaning as Q ₁ in formula (I).
Examples of the organic group for Q ₃ include the same organic groups as Q ₁ and Q ₂ in formula (I).
The divalent linking group for A is preferably a divalent linking group having a fluorine atom having 1 to 8 carbon atoms, such as 1 to 8 carbon atoms, preferably 2 to 6 carbon atoms, more preferably carbon. Examples thereof include an alkylene group having 2 to 4 fluorine atoms and a phenylene group having fluorine atoms. More preferred is an alkylene group having a fluorine atom. The alkylene chain may have a linking group such as an oxygen atom or a sulfur atom. The alkylene group is preferably an alkylene group in which 30 to 100% of the number of hydrogen atoms are substituted with fluorine atoms, more preferably a perfluoroalkylene group, and particularly preferably a perfluoroethylene group, a perfluoropropylene group, or a perfluorobutylene group. .
The monovalent organic group in Qx is preferably an organic group having 4 to 30 carbon atoms, and examples thereof include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and an alkenyl group. Examples of the alkyl group, cycloalkyl group, aryl group, aralkyl group, and alkenyl group are the same as those for Q ₁ and Q ₂ .

In the general formula (III), X ₁ , X ₂ and X ₃ are preferably —SO ₂ —.

  Hereinafter, although the specific example of a compound represented by general formula (II) is shown, this invention is not limited to this.

  The compound that generates the compound having the structure represented by the general formula (II) upon irradiation with actinic rays or radiation is a sulfonium salt of the compound represented by the general formula (II) or a compound represented by the general formula (II) The iodonium salt is preferable.

  The compound that generates the compound represented by the general formula (I) upon irradiation with actinic rays or radiation is more preferably a compound represented by the following general formula (C1) or (C2).

In general formula (C1):
R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
X ⁻ represents an anion of the compound represented by the general formula (I).

In formula (C1), the number of carbon atoms of the organic group as R _201, R ₂₀₂ and R ₂₀₃ is preferably 1 to 30, more preferably 1 to 20.
It is also possible to form the two members ring structure of the R ₂₀₁ to R _203, an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).
Specific examples of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include corresponding groups in the compounds (C1a), (C1b) and (C1c) described later.
In addition, the compound which has two or more structures represented by general formula (C1) may be sufficient. For example, at least one of R ₂₀₁ to R ₂₀₃ of the compound represented by formula (C1) is, at least one bond with structure of R ₂₀₁ to R ₂₀₃ of another compound represented by formula (C1) It may be a compound.

  More preferred components (C1) include compounds (C1a), (C1b) and (C1c) described below.

Compound (C1a) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (C1), 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 a part of R _{201 to} R ₂₀₃ may be an aryl group, and the rest may be an alkyl group or a cycloalkyl group.
Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, diarylcycloalkylsulfonium compounds, aryldialkylsulfonium compounds, aryldicycloalkylsulfonium compounds, arylalkylcycloalkylsulfonium compounds, and the like.
The aryl group of the arylsulfonium compound is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure having an oxygen atom, a nitrogen atom, a sulfur atom or the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue (a group formed by losing one hydrogen atom from pyrrole) and a furan residue (a group formed by losing one hydrogen atom from furan). Groups), thiophene residues (groups formed by the loss of one hydrogen atom from thiophene), indole residues (groups formed by the loss of one hydrogen atom from indole), benzofuran residues ( A group formed by losing one hydrogen atom from benzofuran), a benzothiophene residue (a group formed by losing one hydrogen atom from benzothiophene), and the like. 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, most preferably They are a C1-C4 alkyl group and a C1-C4 alkoxy group. The substituent may be substituted on any one of three R ₂₀₁ to R _203, or may be substituted on 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 (C1b) will be described.
The compound (C1b) is a compound in which R _{201 to} R ₂₀₃ in the general formula (C1) each independently 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 or branched 2-oxoalkyl group, 2-oxocycloalkyl group, An alkoxycarbonylmethyl group, particularly preferably a linear or branched 2-oxoalkyl group.
The alkyl group as R ₂₀₁ to R ₂₀₃ may be linear, it may be either branched, preferably a straight-chain or branched alkyl group (e.g., methyl group having 1 to 20 carbon atoms, an ethyl group, a propyl Group, butyl group, pentyl group). The alkyl group as R ₂₀₁ to R ₂₀₃ is a straight-chain or branched 2-oxoalkyl group, an alkoxycarbonylmethyl group are preferred.
The cycloalkyl group as R ₂₀₁ to R ₂₀₃ is preferably, and a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, norbornyl). The cycloalkyl group as R ₂₀₁ to R ₂₀₃ is a 2-oxocycloalkyl group is more preferable.
The linear or branched 2-oxoalkyl group as R _{201 to} R ₂₀₃ may have a double bond in the chain, and preferably has> C═O at the 2-position of the alkyl group. The group can be mentioned.
The 2-oxocycloalkyl group as R _{201 to} R ₂₀₃ may have a double bond in the chain, and preferably includes a group having> C═O at the 2-position of the cycloalkyl group. be able to.
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), an alkoxycarbonyl group (eg, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group. .

  The compound (C1c) is a compound represented by the following general formula (C1c), and is a compound having an arylacylsulfonium salt structure.

In the general formula (C1c),
_R213 represents an aryl group which may have a substituent, and is preferably a phenyl group or a naphthyl group.
Preferred substituents on the R _213, an alkyl group, an alkoxy group, an acyl group, a nitro group, a hydroxyl group, an alkoxycarbonyl group and a carboxy group.
R ₂₁₄ and R ₂₁₅ each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group.
Y ₂₀₁ and Y ₂₀₂ each independently represents an alkyl group, a cycloalkyl group, an aryl group, or a vinyl group.
X ⁻ represents an anion of the compound represented by the general formula (II).
R ₂₁₃ and R ₂₁₄ may be bonded to form a ring structure, R ₂₁₄ and R ₂₁₅ may be bonded to form a ring structure, and Y ₂₀₁ and Y ₂₀₂ are bonded to each other. To form a ring structure. These ring structures may contain an oxygen atom, a sulfur atom, an ester bond, or an amide bond. Examples of the group R ₂₁₃ and R _214, R ₂₁₄ and R _215, Y ₂₀₁ and Y ₂₀₂ are formed by combined include a butylene group and a pentylene group.

The alkyl group as R ₂₁₄ , R ₂₁₅ , Y ₂₀₁ and Y ₂₀₂ is preferably a linear or branched alkyl group having 1 to 20 carbon atoms. The alkyl group as Y ₂₀₁ and Y ₂₀₂ is a 2-oxoalkyl group having> C═O at the 2-position of the alkyl group, an alkoxycarbonylalkyl group (preferably an alkoxy group having 2 to 20 carbon atoms), or a carboxyalkyl group. More preferred.
The cycloalkyl group as R ₂₁₄ , R ₂₁₅ , Y ₂₀₁ and Y ₂₀₂ is preferably a cycloalkyl group having 3 to 20 carbon atoms.
The aryl group as Y ₂₀₁ and Y ₂₀₂ is preferably a phenyl group or a naphthyl group.
Y ₂₀₁ and Y ₂₀₂ are preferably an alkyl group having 4 or more carbon atoms, more preferably an alkyl group having 4 to 6, and further preferably 4 to 12.
In addition, at least one of R ₂₁₄ or R ₂₁₅ is preferably an alkyl group, and more preferably both R ₂₁₄ and R ₂₁₅ are alkyl groups.

In the general formula (C2),
_R204 and _R205 each independently represents an aryl group, an alkyl group or a cycloalkyl group.
X ⁻ represents an anion of the compound represented by the general formula (II).

In formula (C2), the aryl group of R ₂₀₄ and R _205, a phenyl group, a naphthyl group, more preferably a phenyl group. The aryl group of R ₂₀₄ and R ₂₀₅ may be an aryl group having a heterocyclic structure having an oxygen atom, a nitrogen atom, a sulfur atom, or the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue (a group formed by losing one hydrogen atom from pyrrole) and a furan residue (a group formed by losing one hydrogen atom from furan). Groups), thiophene residues (groups formed by the loss of one hydrogen atom from thiophene), indole residues (groups formed by the loss of one hydrogen atom from indole), benzofuran residues ( A group formed by losing one hydrogen atom from benzofuran), a benzothiophene residue (a group formed by losing one hydrogen atom from benzothiophene), and the like.
The alkyl group as _R204 and _R205 may be either linear or branched, and is preferably a linear or branched alkyl group having 1 to 10 carbon atoms (for example, methyl group, ethyl group, propyl group). Group, butyl group, pentyl group).
The cycloalkyl group as R ₂₀₄ and R ₂₀₅ can preferably be mentioned a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, norbornyl).
_R204 and _R205 may have a substituent. Examples of the substituent that R ₂₀₄ and R ₂₀₅ may have include, 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 (for example, 6 to 6 carbon atoms). 15), alkoxy groups (for example, having 1 to 15 carbon atoms), halogen atoms, hydroxyl groups, phenylthio groups and the like.

  The compound (C) is preferably a compound represented by the general formula (C1), and more preferably a compound represented by the general formulas (C1a) to (C1c).

  Hereinafter, although the specific example of a compound (C) is given, this invention is not limited to this.

  You may use a compound (C) individually or in combination of 2 or more types.

  The content of the compound (C) in the positive resist composition of the present invention is preferably 0.1 to 20% by mass, more preferably 0.1 to 10% by mass, based on the solid content of the composition.

Compound (C) can be easily synthesized by using a general sulfonic acid esterification reaction or sulfonamidation reaction. For example, after selectively reacting one sulfonyl halide part of a bissulfonyl halide compound with an amine or alcohol containing a partial structure represented by the general formula (II) to form a sulfonamide bond or a sulfonate ester bond The other sulfonyl halide moiety can be hydrolyzed, or the cyclic sulfonic acid anhydride can be opened by an amine or alcohol containing a partial structure represented by the general formula (I). Amines and alcohols containing a partial structure represented by the general formula (I) are amines, alcohols under basic conditions (R′O ₂ C) ₂ O, anhydrides such as R′O ₂ CCl, and acid chloride compounds. It can synthesize | combine by making it react.

Basic Compound The positive resist composition of the present invention preferably contains a basic compound in order to reduce a change in performance over time from exposure to heating.

  Preferred examples of the basic compound include compounds represented by the following general formulas (A) to (E).

In the general formula ^{(A), R 250, R} 251 and R ²⁵² each independently represents a hydrogen atom, an alkyl having 1 to 20 carbon atoms, 3 to 20 carbon atoms a cycloalkyl group or having 6 to 20 carbon atoms An aryl group. 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 the general formula (E), R ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R ²⁵⁶ each independently represent an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 20 carbon atoms.

  Preferable compounds include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, and piperidine, and may have a substituent. More preferable compounds include compounds having an imidazole structure, a diazabicyclo structure, an onium hydroxide structure, an onium carboxylate structure, a trialkylamine structure, an aniline structure or a pyridine structure, an alkylamine derivative having a hydroxyl group and / or an ether bond, a hydroxyl group 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.

  In the positive resist composition of the present invention, the basic compound is used alone or in combination of two or more. The amount of the basic compound used is generally 0.001 to 10% by mass, preferably 0.01 to 5% by mass, based on the solid content of the positive resist composition. 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.

Surfactant The positive resist composition of the present invention preferably contains a surfactant and is a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant and silicon-based surfactant, fluorine atom and silicon). It is more preferable to contain any one or two or more surfactants containing both atoms.

  When the positive resist composition of the present invention contains fluorine and / or a silicon-based surfactant, adhesion and development defects are obtained with good sensitivity and resolution when using an exposure light source of 250 nm or less, particularly 220 nm or less. It is possible to provide a resist pattern with less.

  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, 4430 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189 , F113, F110, F177, F120, R08 (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Manufactured by Troy Chemical Co., Ltd.), GF-300, GF-150 (manufactured by Toagosei Chemical Co., Ltd.), Surflon S-393 (manufactured by Seimi Chemical Co., Ltd.), F-top EF121, EF122A, EF122B, RF122C, EF125M , EF135M, EF351, 352, EF801, EF802, EF 01 (manufactured by Gemco), PF636, PF656, PF6320, PF6520 (manufactured by OMNOVA), FTX-204D, 208G, 218G, 230G, 204D, 208D, 212D, 218, 222D (manufactured by Neos) Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

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

  As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. 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.

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

  Surfactants may be used alone or in several combinations.

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

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 having an acid-decomposable group is preferred. The acid-decomposable group is preferably a group in which a carboxyl group or a hydroxyl group is protected with an acid-decomposable protecting 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 obtained by protecting the carboxylic acid with an acid-decomposable protecting group, such as saccharides. A polyol or a compound having its hydroxyl group protected with an acid-decomposable protecting group is preferred.

  The molecular weight of the dissolution controlling compound 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.

Solvent The positive resist composition of the present invention is used by dissolving each component in a predetermined solvent.
Solvents that can be used include, for example, 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- Examples thereof include dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and tetrahydrofuran.

  In the present invention, the solvent may be used alone or mixed, but it is preferable to use a mixed solvent containing two or more kinds of solvents having different functional groups. As the mixed solvent having different functional groups, a mixed solvent in which a solvent having a hydroxyl group in the structure and a solvent having no hydroxyl group are mixed, or a mixed solvent in which a solvent having an ester structure and a solvent having a ketone structure are mixed. Is preferably used. Thereby, the generation of particles during storage of the resist solution can be reduced.

Examples of the solvent having 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. Propylene glycol monomethyl ether,
More preferred is ethyl lactate.

  Examples of the solvent having no hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide. Of 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 ethoxypropio Nate, 2-heptanone and cyclohexanone are particularly preferred.

  The mixing ratio (mass) of the solvent having a hydroxyl group and the solvent having no hydroxyl group is usually 1/99 to 99/1, preferably 10/90 to 90/10, and more preferably 20/80 to 60/40. is there. A mixed solvent containing 50% by mass or more of a solvent having no hydroxyl group is preferable in terms of coating uniformity.

In a mixed solvent in which a solvent having an ester structure and a solvent having a ketone structure are mixed, 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, γ-butyrolactone, and butyl acetate, with propylene glycol monomethyl ether acetate being preferred.
The mixing ratio (mass) of the solvent having an ester structure and the solvent having a ketone structure is usually 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 60/40. is there. 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.

<Other additives>
If necessary, the positive resist composition of the present invention may further contain a dye, a light absorber, a plasticizer, a photosensitizer, a compound that promotes solubility in a developer, and the like.

  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.

  A preferable addition amount of these dissolution promoting compounds is 2 to 50% by mass, and more preferably 5 to 30% by mass with respect to the resin of the component (A). 50 mass% or less is preferable at the point of development residue suppression and the pattern deformation prevention at the time of image 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.

As the plasticizer, in addition to a commercially available plasticizer, any compound having a molecular weight of 1000 or less that is compatible with the polymer to be used and has an effect of lowering the softening point of the film may be used without particular limitation. From the viewpoint of compatibility, the molecular weight is preferably 750 or less, and the molecular weight is 500 or less. A compound having a normal pressure boiling point of 300 ° C. or higher and a melting point of 20 ° C. or lower is preferable. Specific examples include diisobutyl phthalate, tricresyl phosphate, triethylene glycol diphenyl ether, diethylene glycol dibenzoate, and triethylene glycol diacetate.

  As the light absorber, any compound that has absorption at the exposure wavelength and does not generate an acid upon exposure can be used without particular limitation. When the light source wavelength is 193 nm, a compound containing an aromatic ring is preferred. Specific examples include benzene derivatives, naphthalene derivatives, anthracene derivatives, furan derivatives, thiophene derivatives, indole derivatives, and the like.

  When the resist film made of the positive resist composition of the present invention is exposed through an immersion medium, a hydrophobic resin (HR) can be further added as necessary. As a result, hydrophobic resin (HR) is unevenly distributed on the surface of the resist film, and when the immersion medium is water, the receding contact angle of the resist film surface with respect to the water when the resist film is formed is improved, and the immersion water tracking is improved. Can be made. As the hydrophobic resin (HR), 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 receding contact angle of the resist film is 60 ° to 80 °, preferably 70 ° or more. The addition amount can be adjusted and used as appropriate so that the receding contact angle of the resist film falls within the above range, but is preferably 0.1 to 10% by mass based on the total solid content of the positive resist composition, More preferably, it is 0.1-5 mass%.

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

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

The top coat is preferably not mixed with the resist film and further not mixed with the immersion liquid. From this point of view, when the immersion liquid is water, the solvent used for the top coat is preferably a water-insoluble medium that is hardly soluble in the solvent used for the positive resist composition. Furthermore, when the immersion liquid is an organic solvent, the topcoat may be water-soluble or water-insoluble.

Hydrophobic resin (HR)
The positive resist composition of the present invention may contain a hydrophobic resin (HR) that makes the surface of the resist film hydrophobic.
Such a hydrophobic resin (HR) is preferably a resin having at least one of a fluorine atom and a silicon atom.
Further, the hydrophobic resin (HR) can be suitably used as a top coat.
The fluorine atom or silicon atom in the hydrophobic resin (HR) may be contained in the main chain of the resin or may be substituted on the side chain.

The hydrophobic resin (HR) is preferably a resin having an alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom as a partial structure having a fluorine atom.
The alkyl group having a fluorine atom (preferably having 1 to 10 carbon atoms, more preferably 1 to 4 carbon atoms) is a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, It may have a substituent.
The cycloalkyl group having a fluorine atom is a monocyclic or polycyclic cycloalkyl group (preferably having 3 to 10 carbon atoms) in which at least one hydrogen atom is substituted with a fluorine atom, and further has another substituent. It may be.
Examples of the aryl group having a fluorine atom include those in which at least one hydrogen atom of an aryl group such as a phenyl group or a naphthyl group is substituted with a fluorine atom, and may further have another substituent.

  A general formula of an alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom is shown below, but the present invention is not limited thereto.

In general formulas (F2) to (F4),
R _{57 to} R ₆₈ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{57 to} R ₆₁ , R _{62 to} R ₆₄ and R _{65 to} R ₆₈ is a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom (preferably having a carbon number of 1 ~ 4). R _{57 to} R ₆₁ and R _{65 to} R ₆₇ are preferably all fluorine atoms. R ₆₂ , R
₆₃ and R ₆₈ are preferably an alkyl group (preferably having 1 to 4 carbon atoms) in which at least one hydrogen atom is substituted with a fluorine atom, and more preferably a perfluoroalkyl group having 1 to 4 carbon atoms. R ₆₂ and R ₆₃ may be connected to each other to form a ring.

Specific examples of the group represented by the general formula (F2) include a p-fluorophenyl group, a pentafluorophenyl group, and a 3,5-di (trifluoromethyl) phenyl group.
Specific examples of the group represented by the general formula (F3) include trifluoromethyl group, pentafluoropropyl group, pentafluoroethyl group, heptafluorobutyl group, hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro (2 -Methyl) isopropyl group, nonafluorobutyl group, octafluoroisobutyl group, nonafluorohexyl group, nonafluoro-t-butyl group, perfluoroisopentyl group, perfluorooctyl group, perfluoro (trimethyl) hexyl group, 2,2 1,3,3-tetrafluorocyclobutyl group, perfluorocyclohexyl group and the like. Hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro (2-methyl) isopropyl group, octafluoroisobutyl group, nonafluoro-t-butyl group and perfluoroisopentyl group are preferable, and hexafluoroisopropyl group and heptafluoroisopropyl group are preferable. Further preferred.
Specific examples of the group represented by the general formula (F4) include, for example, —C (CF ₃ ) ₂ OH, —C (C ₂ F ₅ ) ₂ OH, —C (CF ₃ ) (CH ₃ ) OH, -CH (CF ₃₎ OH and the like, -C (CF _{3) 2} OH is preferred.

Hereinafter, the specific example of the repeating unit containing group represented by general formula (F2)-(F4) is shown.
In specific examples, X ₁ represents a hydrogen atom, —CH ₃ , —F or —CF ₃ .
X ₂ represents —F or —CF ₃ .

  The hydrophobic resin (HR) is preferably a resin having an alkylsilyl structure (preferably a trialkylsilyl group) or a cyclic siloxane structure as a partial structure having a silicon atom.

  Specific examples of the alkylsilyl structure or the cyclic siloxane structure include groups represented by the following general formulas (CS-1) to (CS-3).

In general formulas (CS-1) to (CS-3),
R _{12 to} R ₂₆ each independently represents a linear or branched alkyl group (preferably having 1 to 20 carbon atoms) or a cycloalkyl group (preferably having 3 to 20 carbon atoms).
L < ₃ > -L < ₅ > represents a single bond or a bivalent coupling group. The divalent linking group is selected from the group consisting of an alkylene group, a phenylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a urethane group or a urea group, or a combination of two or more groups. Can be mentioned.
n represents an integer of 1 to 5.

Hereinafter, although the specific example of the repeating unit which has group represented by general formula (CS-1)-(CS-3) is shown, this invention is not limited to this.
In specific examples, X represents a hydrogen atom, —CH ₃ , —F, or —CF ₃ .

Furthermore, the hydrophobic resin (HR) may contain at least one group selected from the following groups (x) to (z).
(X) an alkali-soluble group,
(Y) a group that decomposes by the action of an alkali developer and increases the solubility in the alkali developer;
(Z) A group that decomposes by the action of an acid.

(X) Alkali-soluble groups include phenolic hydroxyl groups, carboxylic acid groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, (alkylsulfonyl) ( Alkylcarbonyl) imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) And a group having a methylene group.
Preferred alkali-soluble groups include fluorinated alcohol groups (preferably hexafluoroisopropanol), sulfonimide groups, and bis (carbonyl) methylene groups.

  Examples of the repeating unit having an alkali-soluble group (x) include a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or a main group of the resin via a linking group. It is preferable to use a repeating unit in which an alkali-soluble group is bonded to the chain, and further introduce a polymerization initiator or chain transfer agent having an alkali-soluble group at the end of the polymer chain at the time of polymerization.

  The content of the repeating unit having an alkali-soluble group (x) is preferably from 1 to 50 mol%, more preferably from 3 to 35 mol%, still more preferably from 5 to 20 mol%, based on all repeating units in the polymer.

Specific examples of the repeating unit having an alkali-soluble group (x) are shown below, but the present invention is not limited thereto.
In particular, Rx represents H, CH3, CF3, CH2OH.

(Y) Examples of the group that decomposes by the action of an alkali developer and increases the solubility in the alkali developer include a group having a lactone structure, an acid anhydride, an acid imide group, and the like, and preferably a lactone group It is.
The repeating unit having a group (y) that is decomposed by the action of an alkali developer and increases the solubility in the alkali developer includes a resin via a linking group such as a repeating unit of an acrylate ester or a methacrylate ester. Is decomposed by the action of an alkali developer and the repeating unit having a group (y) that increases the solubility in the alkali developer, or decomposed by the action of the alkali developer, and the solubility in the alkali developer is Either a polymerization initiator having an increasing group (y) or a chain transfer agent is introduced at the end of the polymer chain during polymerization.

  The content of the repeating unit having a group (y) that decomposes by the action of the alkali developer and increases the solubility in the alkali developer is preferably from 1 to 40 mol%, more preferably, based on all repeating units in the polymer. Is 3 to 30 mol%, more preferably 5 to 15 mol%.

  Specific examples of the repeating unit having a group (y) that is decomposed by the action of the alkali developer and increases the solubility in the alkali developer are represented by the general formula (AI) mentioned for the resin of the component (A). The same thing as the specific example of the repeating unit which can be mentioned can be mentioned.

  (Z) As a group decomposed | disassembled by the effect | action of an acid, the thing similar to the acid-decomposable group mentioned by resin of (A) component can be mentioned. Examples of the repeating unit (z) having a group capable of decomposing by the action of an acid are the same as the repeating unit having an acid-decomposable group exemplified for the resin of component (A).

  The content of the repeating unit having a group (z) that is decomposed by the action of an acid is preferably from 1 to 80 mol%, more preferably from 10 to 80 mol%, still more preferably from 20 to 60 mol%, based on all repeating units in the polymer. It is.

  Furthermore, the hydrophobic resin (HR) may have a repeating unit represented by the following general formula (V).

In general formula (V),
R ₄ represents a group having an alkyl group, a cycloalkyl group, an alkenyl group, or a cycloalkenyl group.
L ₆ represents a single bond or a divalent linking group.

In general formula (V), the alkyl group represented by R ₄ is preferably a linear or branched alkyl group having 3 to 20 carbon atoms.
The cycloalkyl group is preferably a cycloalkyl group having 3 to 20 carbon atoms.
The alkenyl group is preferably an alkenyl group having 3 to 20 carbon atoms.
The cycloalkenyl group is preferably a cycloalkenyl group having 3 to 20 carbon atoms.
The divalent linking group of L ₆ is preferably an alkylene group (preferably having 1 to 5 carbon atoms) or an oxy group.

  In the hydrophobic resin (HR), the fluorine atom content is preferably 5 to 80% by mass and more preferably 10 to 80% by mass with respect to the molecular weight of the hydrophobic resin (HR). . Moreover, it is preferable that the repeating unit which has a fluorine atom is 10-100 mass% in hydrophobic resin (HR), and it is more preferable that it is 30-100 mass%.

  When the hydrophobic resin (HR) has a silicon atom, the content of the silicon atom is preferably 2 to 50% by mass and preferably 2 to 30% by mass with respect to the molecular weight of the hydrophobic resin (HR). Is more preferable. Moreover, it is preferable that the repeating unit containing a silicon atom is 10-100 mass% in hydrophobic resin (HR), and it is more preferable that it is 20-100 mass%.

  The weight average molecular weight of the hydrophobic resin (HR) in terms of standard polystyrene is preferably 1,000 to 100,000, more preferably 1,000 to 50,000, and even more preferably 2,000 to 15,000. is there.

  The hydrophobic resin (HR), like the resin of the component (A), naturally has few impurities such as metals, and the residual monomer and oligomer components are preferably 0 to 10% by mass, more preferably. Is more preferably 0 to 5% by mass and 0 to 1% by mass. Thereby, a resist having no change over time such as foreign matter in liquid or sensitivity can be obtained. The molecular weight distribution (Mw / Mn, also referred to as dispersity) is preferably 1 to 5, more preferably 1 to 3, in terms of resolution, resist shape, resist pattern side wall, roughness, and the like.

  As the hydrophobic resin (HR), various commercially available products can be used, or they can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method and a polymerization initiator are dissolved in a solvent and the polymerization is carried out by heating, and a solution of the monomer species and the polymerization initiator is added to the heating solvent over 1 to 10 hours. Examples thereof include a dropping polymerization method which is added dropwise, and a dropping polymerization method is preferred. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane and 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 positive resist 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 resist composition of the present invention. Thereby, the generation of particles during storage can be suppressed.

  The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. The concentration of the reaction is 5 to 50% by mass, preferably 30 to 50% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.

  After completion of the reaction, the mixture is allowed to cool to room temperature and purified. Purification can be accomplished by a liquid-liquid extraction method that removes residual monomers and oligomer components by combining water and an appropriate solvent, and a purification method in a solution state such as ultrafiltration that extracts and removes only those having a specific molecular weight or less. , Reprecipitation method that removes residual monomer by coagulating resin in poor solvent by dripping resin solution into poor solvent and purification in solid state such as washing filtered resin slurry with poor solvent A normal method such as a method can be applied. For example, the resin is precipitated as a solid by contacting a solvent (poor solvent) in which the resin is hardly soluble or insoluble in a volume amount of 10 times or less, preferably 10 to 5 times that of the reaction solution.

The solvent (precipitation or reprecipitation solvent) used in the precipitation or reprecipitation operation from the polymer solution may be a poor solvent for the polymer, and may be a hydrocarbon, halogenated hydrocarbon, nitro, depending on the type of polymer. Compound, ether, ketone, ester, carbonate, alcohol,
It can be used by appropriately selecting from carboxylic acid, water, a mixed solvent containing these solvents, and the like. Among these, as a precipitation or reprecipitation solvent, a solvent containing at least an alcohol (particularly methanol or the like) or water is preferable.

  The amount of the precipitation or reprecipitation solvent used can be appropriately selected in consideration of efficiency, yield, and the like, but generally 100 to 10000 parts by mass, preferably 200 to 2000 parts by mass with respect to 100 parts by mass of the polymer solution, More preferably, it is 300-1000 mass parts.

  The temperature for precipitation or reprecipitation can be appropriately selected in consideration of efficiency and operability, but is usually about 0 to 50 ° C., preferably around room temperature (for example, about 20 to 35 ° C.). The precipitation or reprecipitation operation can be performed by a known method such as a batch method or a continuous method using a conventional mixing vessel such as a stirring tank.

  The precipitated or re-precipitated polymer is usually subjected to conventional solid-liquid separation such as filtration and centrifugation, and dried before use. Filtration is performed using a solvent-resistant filter medium, preferably under pressure. Drying is performed at a temperature of about 30 to 100 ° C., preferably about 30 to 50 ° C. under normal pressure or reduced pressure (preferably under reduced pressure).

  The resin may be once deposited and separated, and then dissolved again in a solvent, and the resin may be brought into contact with a hardly soluble or insoluble solvent. That is, after completion of the radical polymerization reaction, a solvent in which the polymer is hardly soluble or insoluble is brought into contact, the resin is precipitated (step a), the resin is separated from the solution (step b), and dissolved again in the solvent. (Step c), and then contact the resin solution A with a solvent in which the resin is hardly soluble or insoluble in a volume amount less than 10 times that of the resin solution A (preferably 5 times or less volume). This may be a method including precipitating a resin solid (step d) and separating the precipitated resin (step e).

  Specific examples of the resin are shown below. Table 1 below shows the molar ratio of the repeating units in each resin (corresponding to each repeating unit in order from the left), the weight average molecular weight, and the degree of dispersion.

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

  For example, a positive resist composition is formed on a substrate (for example, silicon / silicon dioxide coating) used for manufacturing a precision integrated circuit element by an appropriate coating method such as a spinner or a coater to have an arbitrary thickness (usually 50 to 500 nm). ). After application, the resist film is formed by drying by spinning or baking. The baking temperature can be appropriately set, but is usually 60 to 150 ° C, preferably 90 to 130 ° C.

Next, exposure is performed through a mask or the like for pattern formation.
Although an exposure amount can be set suitably, it is 1-100 mJ / cm < ² > normally. After exposure, preferably, spinning or / and baking is performed, development and rinsing are performed to obtain a pattern.

  Exposure (immersion exposure) may be performed by filling a liquid (immersion medium) having a higher refractive index than air between the resist film and the lens during irradiation with actinic rays or radiation. Thereby, resolution can be improved. As the immersion medium to be used, any liquid can be used as long as it has a higher refractive index than air, but pure water is preferred. Further, an overcoat layer may be further provided on the resist film so that the immersion medium and the resist film do not come into direct contact with each other during immersion exposure. Thereby, elution of the composition from the resist film to the immersion medium is suppressed, and development defects are reduced.

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.

Before forming the resist 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.

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.

The positive resist composition of the present invention may be applied to a multilayer resist process (particularly a three-layer resist process). The multilayer resist method includes the following processes.
(a) A lower resist layer made of an organic material is formed on a substrate to be processed.
(b) On the lower resist layer, an intermediate layer and an upper resist layer made of an organic material that crosslinks or decomposes upon irradiation are sequentially laminated.
(c) After forming a predetermined pattern in the upper resist layer, the intermediate layer, the lower layer and the substrate are sequentially etched.
As the intermediate layer, organopolysiloxane (silicone resin) or SiO ₂ coating solution (SOG) is generally used. As the lower layer resist, an appropriate organic polymer film is used, but various known photoresists may be used. For example, the FH series, FHi series manufactured by Fuji Film Arch, or the PFI series manufactured by Sumitomo Chemical can be exemplified.
The film thickness of the lower resist layer is preferably 0.1 to 4.0 μm, more preferably 0.2 to 2.0 μm, and particularly preferably 0.25 to 1.5 μm. A thickness of 0.1 μm or more is preferable from the viewpoint of antireflection and dry etching resistance, and a thickness of 4.0 μm or less is preferable from the viewpoint of aspect ratio and pattern collapse of the formed fine pattern.

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

Synthesis Example 1 (Synthesis of Resin (A-1))
Under a nitrogen stream, 8.8 g of cyclohexanone was placed in a three-necked flask and heated to 80 ° C. To this, 8.5 g of the following monomer (LM-1), 4.7 g of the following monomer (PM-1), 8.8 g of the following monomer (IM-1), and a polymerization initiator V-60 (manufactured by Wako Pure Chemical Industries, Ltd.) A solution in which 13 mol% was dissolved in 79 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 20 minutes to a mixture of methanol 900 m / water 100 ml. The precipitated powder was collected by filtration and dried, yielding 18 g of Resin (A-1). The composition ratio of the obtained resin was 49/11/40, the weight average molecular weight was 6200 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.63.

Resins (A-2) to (A-15) and a comparative resin (Ref-1) were synthesized in the same manner as in Synthesis Example 1.
The structure of the synthesized resin is shown below.

Table 2 below shows the monomers, monomer ratio, weight average molecular weight, and degree of dispersion used in the synthesis for the resins (A-2) to (A-15) and the comparative resin (Ref-1). The monomer ratio corresponds to the order from the left of each monomer.

The monomers listed in Table 2 are shown below.

Examples 1-15 and Comparative Examples 1-2
The components shown in Table 3 below were dissolved in a solvent to prepare a solution having a solid content concentration of 5%, and this was filtered through a 0.1 μm polyethylene filter to prepare a positive resist solution. The prepared positive resist solution was evaluated by the following method.
An antireflective film ARC29A manufactured by Nissan Chemical Industries, Ltd. was uniformly applied to a 78 nm thickness on a silicon substrate with a spin coater, dried on a hot plate at 205 ° C. for 60 seconds, and then cooled to room temperature. Thereafter, each positive resist solution was applied by a spin coater and dried at 120 ° C. for 60 seconds to form a 160 nm resist film.
This resist film is exposed with an ArF excimer laser stepper (SM = NA = 0.75) through an 85 nm 1: 1 line-and-space mask while changing the exposure amount. After heating above, it was cooled to room temperature. Further, the film was developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 30 seconds, rinsed with pure water for 30 seconds, and then dried to obtain a line pattern.
Exposure latitude (EL) evaluation:
The exposure amount that reproduces a line pattern of 85 nm (line / space = 1/1) is the optimum exposure amount, and when the exposure amount is changed, an exposure amount width that allows a pattern size of 85 nm ± 10% is obtained, and this value is obtained. Was divided by the optimum exposure and displayed as a percentage. The larger the value, the smaller the change in performance due to the change in exposure amount, and the better the exposure latitude.
Pattern collapse performance:
The scanning electron microscope (SEM) shows the pattern when the exposure dose is changed to 10 mJ / cm ^-2 on the overexposure side with respect to the exposure dose E1 that reproduces a line pattern of 85 nm (line / space = 1/1). , The case where pattern collapse did not occur was indicated as 起 こ っ, the case where only slight pattern collapse occurred, and the case where pattern collapse occurred as ×.
Focus margin evaluation:
When the focus at the time of exposure is shifted up and down by 0.1 μm with respect to the optimum exposure amount for forming a 1: 1 line and space pattern with a line width of 85 nm, the line width is within a range of ± 10% from the target line width of 90 nm. The maximum value of the defocus in a range that does not deteriorate the pattern shape is taken as the focus margin. The larger the value, the greater the tolerance for defocus.

  The compounds corresponding to the abbreviations in Table 3 are the compounds shown below.

[Basic compounds]
N-1: N, N-dibutylaniline N-2: Trioctylamine N-3: N, N-dihydroxyethylaniline N-4: 2,4,5-triphenylimidazole N-5: 2,6-diisopropyl Aniline N-6: Hydroxyantipyrine N-7: Trismethoxymethoxyethylamine N-8: Triethanolamine

  [Solution control compound]

[Surfactant]
W-1: MegaFuck F176 (Dainippon Ink Chemical Co., Ltd.) (Fluorine)
W-2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.) (fluorine and silicon)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) (silicon-based)
W-4: Troisol S-366 (manufactured by Troy Chemical Co., Ltd.)
W-5: KH-20 (Asahi Kasei Corporation)
W-6: PF6320 (made by OMNOVA)
W-7: PF6520 (made by OMNOVA)

〔solvent〕
Group a SL-1: Propylene glycol monomethyl ether acetate SL-2: Propylene glycol monomethyl ether propionate SL-3: 2-heptanone Group b SL-4: Ethyl lactate SL-5: Propylene glycol monomethyl ether SL-6: Cyclohexanone Group c SL-7: γ-butyrolactone SL-8: Propylene carbonate

  From Table 3, it is clear that the positive resist composition of the present invention is excellent in exposure latitude, focus margin, and pattern collapse performance.

Examples 16-30
The components shown in Table 4 below were dissolved in a solvent to prepare a solution having a solid content concentration of 5%, and this was filtered through a 0.1 μm polyethylene filter to prepare a positive resist solution.
An antireflection film ARC29A (Brewer Science Co., Ltd.) was applied on a silicon wafer, and baked at 205 ° C. for 60 seconds to form a 78 nm antireflection film. A positive resist solution prepared thereon was applied and baked at 120 ° C. for 60 seconds to form a 160 nm-thick resist film. The obtained wafer was subjected to pattern exposure using an ArF excimer laser immersion scanner (NA 0.75). As the immersion liquid, ultrapure water having impurities of 5 ppb or less was used. Thereafter, the mixture was heated at 120 ° C. for 60 seconds, developed with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsed with pure water, and then spin-dried to obtain a line pattern. .
In the same manner as in Example 1, the exposure latitude, focus margin, and pattern collapse performance were evaluated, and the results are shown in Table 4 below.

  From Table 4, it is apparent that the positive resist composition of the present invention is excellent in exposure latitude, focus margin and pattern collapse performance in pattern formation by ArF immersion exposure.

Claims (5)

(A) Resin having an acid-decomposable repeating unit represented by the following general formula (I), which increases the solubility in an alkali developer by the action of an acid, (B) Generates an acid upon irradiation with actinic rays or radiation And a positive resist composition comprising: (C) a compound that generates a compound represented by the following general formula (II) upon irradiation with actinic rays or radiation.

In general formula (I),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
Ry _{1 to} Ry ₃ each independently represents an alkyl group or a cycloalkyl group. At least two members out of Ry _{1 to} Ry ₃ may be bonded to form a ring structure.
Z represents a divalent linking group.

In general formula (II):
Q ₁ and Q ₂ each independently represents a monovalent organic group. However, either Q ₁ or Q ₂ has a proton acceptor functional group. Q ₁ and Q ₂ may combine to form a ring, and the formed ring may have a proton acceptor functional group.
X ₁ and X ₂ each independently represent —CO— or —SO ₂ —.   2. The positive resist composition according to claim 1, wherein in the general formula (I), Z is a divalent chain hydrocarbon group or a divalent cyclic hydrocarbon group. The positive resist composition according to claim 1 or 2, wherein the compound represented by the general formula (II) is represented by the following general formula (III).

In general formula (III):
Q ₁ and Q ₃ each independently represents a monovalent organic group. However, _one of Q ₁ and Q ₃ has a proton acceptor functional group. Q ₁ and Q ₃ may combine to form a ring, and the formed ring may have a proton acceptor functional group.
X ₁ , X ₂ and X ₃ each independently represent —CO— or —SO ₂ —.
A represents a divalent linking group.
B represents a single bond, an oxygen atom, or —N (Qx) —.
Qx represents a hydrogen atom or a monovalent organic group.
When B is —N (Qx) —, Q ₃ and Qx may combine to form a ring.
n represents 0 or 1.   The compound that generates the compound represented by the general formula (II) or the general formula (III) upon irradiation with actinic rays or radiation is a sulfonium salt of the compound represented by the general formula (II) or the general formula (III) The positive resist composition according to claim 1, wherein the positive resist composition is an iodonium salt of a compound represented by the formula (II) or the general formula (III).   A pattern forming method comprising: forming a film with the positive resist composition according to claim 1, exposing the film, and developing the film.