JP4742156B2 - Positive resist composition and pattern forming method using the same - Google Patents

Description

  The present invention relates to a positive resist composition used in an ultramicrolithography process such as the manufacture of VLSI and high-capacity microchips and other photofabrication processes. More specifically, the present invention relates to a positive resist composition in which a resist pattern having an excellent pattern profile is formed after exposure and development with high resolution and high sensitivity.

In recent years, the degree of integration of integrated circuits has increased further, and in the manufacture of semiconductor substrates such as VLSI, processing of ultra-fine patterns having a line width of less than half a micron has been required. In order to satisfy this need, the wavelength used by exposure apparatuses used in photolithography has become increasingly shorter, and now it is considered to use excimer laser light (XeCl, KrF, ArF, etc.) having a short wavelength among far ultraviolet rays. It is becoming.
A chemical amplification type resist is used for lithography pattern formation in this wavelength region.

  In general, chemically amplified resists can be broadly classified into three types, commonly called two-component systems, 2.5-component systems, and three-component systems. The two-component system combines a compound that generates an acid by photolysis (hereinafter referred to as a photoacid generator) and a binder resin. The binder resin is a resin having in its molecule a group (also referred to as an acid-decomposable group) that decomposes by the action of an acid and increases the solubility of the resin in an alkaline developer. The 2.5 component system further contains a low molecular weight compound having an acid-decomposable group in the two component system. A three-component system contains a photoacid generator, an alkali-soluble resin, and the low molecular weight compound.

  The chemical amplification resist is suitable as a photoresist for irradiation with ultraviolet rays or far ultraviolet rays, but among them, it is necessary to cope with the required characteristics in use. As a photoresist composition for an ArF light source, a photoresist composition in which a (meth) acrylic resin that absorbs less light than a partially hydroxylated styrene resin is combined with a compound that generates an acid by light is proposed. ing. For example, there are Patent Documents 1 and 2. In particular, Patent Document 3 discloses a resin in which a tertiary carbon organic group is ester-bonded to oxygen of a carboxyl group of acrylic acid.

  Further, Patent Document 4 discloses an acid-decomposable resin having an acrylic ester or a fumarate ester as a repeating structural unit, but the actual situation is that the pattern profile is not good and satisfactory performance is not obtained.

Furthermore, a resin having an alicyclic hydrocarbon moiety introduced for the purpose of imparting dry etching resistance has been proposed.
Patent Documents 5 to 7 use an acid-sensitive compound containing an alkali-soluble group protected with a structure containing an alicyclic group and a structural unit that makes the alkali-soluble group detachable with an acid and makes it alkali-soluble. The resist material that was found is described.

In addition, lithography processes for device manufacturing in which the wavelength of exposure radiation is in the conventional ultraviolet (UV) or deep UV region (ie, about 240 nm to about 370 nm) have ethylenic or aromatic unsaturation. A resist material containing a polymer (polymer) is generally used. However, such resist materials are often unsuitable for processes with exposure radiation of 193 nm. The reason is that the carbon-carbon double bond absorbs radiation at this wavelength. As a result, resist materials used in lithography processes where the wavelength of exposure radiation is 248 nm or greater are generally not used in processes that use exposure radiation at a wavelength of 193 nm. Lithographic processes that produce devices using 0.18 μm and 0.13 μm design rules often use light with a wavelength of 193 nm as exposure radiation, so resist polymers that do not contain much ethylenic unsaturation are desired. .
In Patent Documents 8 and 9, although transparency with respect to a wavelength of 193 nm is improved, it cannot necessarily be said to be highly sensitive, and the resolution is insufficient when considering lithography of 0.13 μm or later.
Patent Documents 6 and 10 to 12 describe resist compositions containing an acid-decomposable resin having a specific lactone structure.

  In the chemically amplified photoresist for ArF exposure, various resins containing acid-decomposable groups have been studied as described above, but there is still room for improvement. That is, sufficient sensitivity and resolution for radiation with a wavelength of 193 nm are required. Furthermore, there is a need for a chemically amplified photoresist that can provide excellent resolution and pattern profile even after considerable time elapses after exposure until post-heating, that is, high process tolerance.

Japanese Unexamined Patent Publication No. 7-199467 JP 7-252324 A JP-A-6-289615 JP-A-7-234511 JP-A-9-73173 JP-A-9-90637 JP-A-10-161313 Japanese Patent Laid-Open No. 10-10739 JP-A-10-307401 JP-A-10-207069 JP-A-10-274852 Japanese Patent Laid-Open No. 11-12326

  Therefore, the object of the present invention is to solve the above-mentioned problems of the performance improvement technology inherent in microphotofabrication using far ultraviolet light, particularly ArF excimer laser light (wavelength 193 nm). An object of the present invention is to provide a positive resist composition having sufficient sensitivity and resolution for exposure at a wavelength of 193 nm, and capable of obtaining an excellent resolution and pattern profile even if a considerable amount of time elapses after the exposure until post-heating.

As a result of earnestly examining the constituent materials of the positive chemical amplification resist composition, the present inventors have used a photoacid generator having a specific structure together with an acid-decomposable resin having a repeating structural unit having a specific structure. Knowing that the object of the present invention has been achieved, the present invention has been achieved.
That is, the above object is achieved by the following configuration.
(1) (A) It contains a repeating structural unit represented by the following general formula (I) and a repeating structural unit represented by the following general formula (II), and the dissolution rate in an alkali developer is increased by the action of an acid. A positive electrode comprising a resin, (B) a compound represented by the following general formula (I ′) that generates sulfonic acid upon irradiation with actinic rays or radiation, and a fluorine-based and / or silicon-based surfactant. Type resist composition.

In the above general formula (I):
R ₀₁ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
R ₀₂ represents an alkyl group having 1 to 4 carbon atoms.
In the above general formula (II):
R ₀₁ each independently represents a hydrogen atom or a methyl group.
W represents a single bond.
Rb, Rc, Rd, Re, and Rf in Lc each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, but the number of alkyl groups having 1 to 4 carbon atoms is at most three.
Ra represents a single bond and is bonded to W.
m and n each independently represents an integer of 0 to 2, and m + n is 2.

In the above general formula (I ′):
R _{1 to} R ₁₅ are the same or different and are a hydrogen atom, linear, branched or cyclic alkyl group, linear, branched or cyclic alkoxy group, hydroxyl group, halogen atom, or —S—R ₃₈ group. Represents. _R38 represents a linear, branched or cyclic alkyl group or an aryl group.
Two or more of R _{1 to} R ₁₅ may be bonded to form a ring containing one or more selected from a single bond, carbon, oxygen, sulfur, and nitrogen.
X ^- is, R ^F SO ₃ ^- represents a. Here, R ^F is a fluorine-substituted linear alkyl group represented by CF ₃ (CF ₂ ) y (where y is an integer of 1 to 9).
(2) The positive resist composition as described in (1) above, wherein y is an integer of 1 to 7.
(3) The positive resist composition as described in (1) above, wherein y is an integer of 1 to 4.
(4) The above-mentioned (1) to (3 ), wherein 0.001 to 2% by mass of fluorine-based and / or silicon-based surfactant is contained based on the total solid content of the positive resist composition. the positive resist composition according to any one of).
(5) The positive resist composition as described in any one of (1) to (4) above, which further contains a nitrogen-containing basic compound.
(6) A pattern forming method comprising: forming a resist film from the positive resist composition according to any one of (1) to (5 ) above; and exposing and developing the resist film.
Although this invention is invention of the said (1)-(6), below, it describes also including another matter.

  The positive resist composition of the present invention is suitable for far-ultraviolet light, particularly ArF excimer laser light having a wavelength of 193 nm, and has a high sensitivity and an excellent resolution enough to resolve a 0.18 μm line. In addition, even if the elapsed time from exposure to post-heating is considerable, the resolution and resist profile hardly change, and the process tolerance is excellent. Therefore, it is suitably used for lithography using far ultraviolet rays such as ArF excimer laser exposure.

Hereinafter, the components used in the present invention will be described in detail.
[1] (A) A resin whose rate of dissolution in an alkaline developer is increased by the action of an acid (hereinafter also referred to as “acid-decomposable resin”).
In the general formulas (I) and (II) showing the repeating structural units of the acid-decomposable resin, R ₀₁ , R ₀₂ , Ra to Rf are alkyl groups having 1 to 4 carbon atoms, such as methyl, ethyl and propyl groups. Isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group and the like.

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

  The acid-decomposable resin can contain repeating structural units represented by the following general formulas (III-a) to (III-d).

In the above general formulas (III-a) to (III-d):
R ₁ represents a hydrogen atom or a methyl group.
R _{3 to} R ₁₀ each independently represents a hydrogen atom or an alkyl group which may have a substituent.
R represents a hydrogen atom or an alkyl group, cyclic alkyl group, aryl group or aralkyl group which may have a substituent.
m represents an integer of 1 to 10.
X is a single bond, an alkylene group which may have a substituent, a cyclic alkylene group which may have a substituent, an arylene group which may have a substituent, an ether group, a thioether group, a carbonyl Represents a divalent group that is not decomposed by the action of an acid, a group, an ester group, an amide group, a sulfonamide group, a urethane group, a urea group, or a combination thereof.
Z represents a single bond, an ether group, an ester group, an amide group, an alkylene group, or a divalent group obtained by combining these.
R ₁₁ represents a single bond, an alkylene group, an arylene group, or a divalent group obtained by combining these.
R ₁₂ represents an alkyl group which may have a substituent, a cyclic alkyl group which may have a substituent, an aryl group which may have a substituent, or an aralkyl which may have a substituent. Represents a group.
R ₁₃ represents an alkylene group, an arylene group, or a divalent group obtained by combining these.
R ₁₄ may have a hydrogen atom, a substituent, an alkyl group that may have a substituent, a cyclic alkyl group that may have a substituent, or a substituent. It represents a good alkenyl group, an aryl group which may have a substituent, or an aralkyl group which may have a substituent.
A represents any of the functional groups shown below.

In the general formulas (III-a) to (III-d), the alkyl groups of R _{3 to} R ₁₀ , R, R ₁₂ , and R ₁₄ may be either linear or branched and have a substituent. It may be. The linear or branched alkyl group is preferably one having 1 to 12 carbon atoms, more preferably one having 1 to 10 carbon atoms, specifically a methyl group, an ethyl group, a propyl group, an isopropyl group, Preferred examples include n-butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group and decyl group.
Examples of the cyclic alkyl group represented by R, R ₁₂ and R ₁₄ include those having 3 to 30 carbon atoms, specifically, cyclopropyl group, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group, boronyl group, Examples thereof include a tricyclodecanyl group, a dicyclopentenyl group, a nobornane epoxy group, a menthyl group, an isomenthyl group, a neomenthyl group, a tetracyclododecanyl group, and a steroid residue.

Examples of the aryl group for R, R ₁₂ and R ₁₄ include those having 6 to 20 carbon atoms, which may have a substituent. Specifically, a phenyl group, a tolyl group, a naphthyl group, etc. are mentioned.
Examples of the aralkyl group for R, R ₁₂ , and R ₁₄ include those having 7 to 20 carbon atoms, which may have a substituent. Specific examples include a benzyl group, a phenethyl group, and a cumyl group.
Examples of the alkenyl group for R ₁₄ include alkenyl groups having 2 to 6 carbon atoms, specifically vinyl, propenyl, allyl, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, A 3-oxocyclohexenyl group, a 3-oxocyclopentenyl group, a 3-oxoindenyl group and the like can be mentioned. Of these, the cyclic alkenyl group may contain an oxygen atom.

As the linking group X, an alkylene group, cyclic alkylene group, arylene group or ether group, thioether group, carbonyl group, ester group, amide group, sulfonamide group, urethane group, urea which may have a substituent Examples thereof include a divalent group selected from the group consisting of groups, or a combination of at least two of these groups and not decomposing by the action of an acid.

Z represents a single bond, an ether group, an ester group, an amide group, an alkylene group, or a divalent group obtained by combining these.
R ₁₁ represents a single bond, an alkylene group, an arylene group, or a divalent group obtained by combining these.
R ₁₃ represents an alkylene group, an arylene group, or a divalent group obtained by combining these.
In X, R ₁₁ and R ₁₃ , examples of the arylene group include those having 6 to 10 carbon atoms, which may have a substituent. Specific examples include a phenylene group, a tolylene group, and a naphthylene group.
Examples of the cyclic alkylene group for X include those in which the aforementioned cyclic alkyl group is divalent.
Examples of the alkylene group in X, Z, R ₁₁ and R ₁₃ include groups represented by the following formulae.
-[C (Rf) (Rg)] r-
In the above formula, Rf and Rg represent a hydrogen atom, an alkyl group, a substituted alkyl group, a halogen atom, a hydroxyl group, or an alkoxy group, and both may be the same or different. The alkyl group is preferably a lower alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, or a butyl group, and more preferably selected from a methyl group, an ethyl group, a propyl group, and an isopropyl group. Examples of the substituent of the substituted alkyl group include a hydroxyl group, a halogen atom, and an alkoxy group. Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Examples of the halogen atom include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom. r is an integer of 1-10.
Specific examples of the linking group X are shown below, but the contents of the present invention are not limited thereto.

As further substituents in the above alkyl group, cyclic alkyl group, alkenyl group, aryl group, aralkyl group, alkylene group, cyclic alkylene group, arylene group, carboxyl group, acyloxy group, cyano group, alkyl group, substituted alkyl group, Examples include a halogen atom, a hydroxyl group, an alkoxy group, an acetylamide group, an alkoxycarbonyl group, and an acyl group.
Examples of the alkyl group include lower alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. Examples of the substituent of the substituted alkyl group include a hydroxyl group, a halogen atom, and an alkoxy group. Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Examples of the acyloxy group include an acetoxy group. Examples of the halogen atom include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom.

  Hereinafter, as specific examples of the structure of the side chain in the general formula (III-b), the structure of the side chain excluding X is shown below, but is not limited thereto.

  Specific examples of the monomer corresponding to the repeating structural unit represented by formula (III-c) are shown below, but are not limited thereto.

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

In general formula (III-b), R _{3 to} R ₁₀ are preferably a hydrogen atom or a methyl group. R is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. m is preferably 1-6.
In the general formula (III-c), R ₁₁ is preferably an alkylene group such as a single bond, a methylene group, an ethylene group, a propylene group, or a butylene group, and R ₁₂ has 1 carbon atom such as a methyl group or an ethyl group. -10 alkyl groups, cyclopropyl groups, cyclohexyl groups, cyclic alkyl groups such as camphor residues, naphthyl groups, and naphthylmethyl groups are preferred. Z is preferably a single bond, an ether bond, an ester bond, an alkylene group having 1 to 6 carbon atoms, or a combination thereof, more preferably a single bond or an ester bond.
In general formula (III-d), R ₁₃ is preferably an alkylene group having 1 to 4 carbon atoms. R ₁₄ may have a substituent, an alkyl group having 1 to 8 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a neopentyl group, or an octyl group, a cyclohexyl group, an adamantyl group Group, norbornyl group, boronyl group, isobornyl group, menthyl group, morpholino group, 4-oxocyclohexyl group, which may have a substituent, phenyl group, toluyl group, mesityl group, naphthyl group, camphor residue is preferable . As these further substituents, a halogen atom such as a fluorine atom, an alkoxy group having 1 to 4 carbon atoms and the like are preferable.

  Among the general formulas (III-a) to (III-d), the repeating structural units represented by the general formula (III-b) and the general formula (III-d) are preferable.

  In addition to the above repeating structural units, the acid-decomposable resin as component (A) includes dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general required characteristics of resist, resolving power and heat resistance. Various repeating structural units can be contained for the purpose of adjusting properties, sensitivity and the like.

Examples of such repeating structural units include, but are not limited to, repeating structural units corresponding to the following monomers.
Thereby, the performance required for the acid-decomposable resin, 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.

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

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

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

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

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

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

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

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

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

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

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

The content of the repeating structural unit represented by formula (I) in the acid-decomposable resin is preferably from 30 to 80 mol%, more preferably from 32 to 75 mol%, still more preferably from 35 to 75 mol% in all repeating structural units. 70 mol%.
In the acid-decomposable resin, the content of the repeating structural unit represented by the general formula (II) is preferably 30 to 70 mol%, more preferably 32 to 68 mol%, still more preferably in all repeating structural units. 35 to 65 mol%.
In the acid-decomposable resin, the content of the repeating structural units represented by the general formulas (III-a) to (III-d) is preferably 0 to 20 mol%, more preferably 0 to 18 in all repeating structural units. It is mol%, More preferably, it is 0-16 mol%.

  Further, the content of the repeating structural unit based on the monomer of the further copolymer component in the resin can be appropriately set according to the performance of the desired resist. Generally, the general formula (I) And 99 mol% or less is preferable with respect to the total mol number which totaled the repeating structural unit shown by (II), More preferably, it is 90 mol% or less, More preferably, it is 80 mol% or less.

  The molecular weight of the acid-decomposable resin as described above is a weight average (Mw: polystyrene conversion value by GPC method), preferably 1,000 to 1,000,000, more preferably 1,500 to 500,000, Preferably, it is in the range of 2,000 to 200,000, more preferably 2,500 to 100,000, and the larger the value, the better the heat resistance and the like, while the developability and the like are lowered, and these are preferable due to the balance. Adjusted to range. The acid-decomposable resin used in the present invention can be synthesized according to a conventional method (for example, radical polymerization).

  In the positive resist composition of the present invention, the compounding amount of the acid-decomposable resin in the entire resist composition is preferably 40 to 99.99% by mass, more preferably 50 to 99.97% by mass in the total solid content. is there.

  Below, the preferable specific example of the combination of the repeating structural unit of the acid-decomposable resin which is (A) component is shown.

[2] (B) Compound that generates acid upon irradiation with actinic ray or radiation (photoacid generator)
In the present invention, at least a compound represented by the general formula (I ′) among the compounds represented by the general formulas (I ′) to (III ′) is used as the photoacid generator.

In the general formulas (I ′) to (III ′):
R _{1 to} R ₃₇ are the same or different and each represents a hydrogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, a hydroxyl group, a halogen atom, or a —S—R ₃₈ group. Represents. _R38 represents a linear, branched or cyclic alkyl group or an aryl group. Also, one or two selected from R _{1 to} R ₁₅ , R _{16 to} R ₂₇ , R _{28 to} R ₃₇ are bonded to each other to form a single bond, carbon, oxygen, sulfur, and nitrogen. A ring including the above may be formed.
In the general formulas (I ′) to (III ′), the linear or branched alkyl group represented by R _{1 to} R ₃₈ may have a substituent, such as a methyl group, an ethyl group, a propyl group, n- Examples thereof include those having 1 to 4 carbon atoms such as a butyl group, a sec-butyl group, and a t-butyl group. Examples of the cyclic alkyl group include those having 3 to 8 carbon atoms, such as a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group, which may have a substituent.
Examples of the linear or branched alkoxy group represented by R _{1 to} R ₃₇ include a methoxy group, an ethoxy group, a hydroxyethoxy group, a propoxy group, an n-butoxy group, an isobutoxy group, a sec-butoxy group, and a t-butoxy group. Such a thing with 1-4 carbon atoms is mentioned.
Examples of the cyclic alkoxy group include a cyclopentyloxy group such as a cyclopentyloxy group and a cyclohexyloxy group.
Examples of the halogen atom represented by R _{1 to} R ₃₇ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the aryl group for R ₃₈ include those having 6 to 14 carbon atoms which may have a substituent such as a phenyl group, a tolyl group, a methoxyphenyl group, and a naphthyl group.
These substituents are preferably an alkoxy group having 1 to 4 carbon atoms, a halogen atom (fluorine atom, chlorine atom, iodine atom), an aryl group having 6 to 10 carbon atoms, and an alkenyl group having 2 to 6 carbon atoms. , Cyano group, hydroxy group, carboxy group, alkoxycarbonyl group, nitro group and the like.
One or more selected from a single bond, carbon, oxygen, sulfur, and nitrogen formed by combining two or more of R _{1 to} R ₁₅ , R _{16 to} R ₂₇ , and R _{28 to} R ₃₇ , or Examples of the ring containing two or more types include a furan ring, a dihydrofuran ring, a pyran ring, a trihydropyran ring, a thiophene ring, and a pyrrole ring.

In the general formula (I ′), X ⁻ is an anion represented by R ^F SO ₃ ^— . Here, R ^F is a fluorine-substituted linear alkyl group having 2 or more carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 8 carbon atoms, and more preferably 2 to 5 carbon atoms.
In the general formula (II ′) or (III ′), X ⁻ is an anion represented by R ^F SO ₃ ^— . Here, R ^F is a fluorine-substituted linear, branched or cyclic group having 2 or more carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 8 carbon atoms, more preferably 2 to 5 carbon atoms. It is an alkyl group.
Preferred R ^F is a fluorine-substituted linear alkyl group represented by CF ₃ (CF ₂ ) y, wherein y is an integer of 1 to 9, more preferably y is an integer of 1 to 7, more preferably y is an integer of 1 to 4 fluorine-substituted linear alkyl group. By using these fluorine-substituted linear alkyl groups [CF ₃ (CF ₂ ) y], the balance between sensitivity and resolving power is excellent, and the change in performance is reduced with time from exposure to post-heating.
Specifically, as R ^F , CF ₃ CF ₂ —, CF ₃ (CF ₂ ) ₂ —, CF ₃ (CF ₂ ) ₃ —, CF ₃ (CF ₂ ) ₄ —, CF ₃ (CF ₂ ) _{5 -, CF 3 (CF 2)} 6 -, CF 3 (CF 2) 7 -, CF 3 (CF 2) 8 -, CF 3 (CF 2) 9 - a preferably exemplified, more preferably CF ₃ (CF ₂ ) ₃ −, CF ₃ (CF ₂ ) ₇ —, and most preferably CF ₃ (CF ₂ ) ₃ —.

A particularly preferred photoacid generator is a compound represented by the general formula (I ′) and X ⁻ is CF ₃ (CF ₂ ) ₃ SO ₃ ^— .

  Such a compound represented by the general formula (I ′) composed of a sulfonate anion having an alkyl group substituted with a fluorine atom is used as a photoacid generator, and the resin component (A ), The positive resist composition of the present invention has sufficient sensitivity and resolution for exposure to far ultraviolet light, particularly ArF excimer laser light (wavelength 193 nm), and is excellent with respect to time after exposure. Maintain the pattern profile and resolution.

  Specific examples of the photoacid generators represented by the general formulas (I ′) to (III ′) include the following compounds (I-1) to (I-32), (II-1) to (II-11) , (III-1) to (III-22).

  The addition amount of the (B) photoacid generator represented by the general formula (I ′) is usually used in a range of 0.001 to 40% by mass, preferably 0 based on the solid content in the composition. 0.01 to 20% by mass, more preferably 0.1 to 5% by mass. If the addition amount of the photoacid generator is less than 0.001% by mass, the sensitivity is lowered, and if the addition amount is more than 40% by mass, the light absorption of the resist becomes too high, resulting in deterioration of the profile and process (especially baking). ) Margin becomes narrow, which is not preferable.

In the positive resist composition of the present invention, a photoacid generator other than the compound represented by the general formula (I ′) can be used in combination.
Examples of photoacid generators that can be used in combination include photocationic photoinitiators, photoinitiators of radical photopolymerization, photodecolorants of dyes, photochromic agents, and known photoresists. Acid (400-200 nm ultraviolet light, far ultraviolet light, particularly preferably g-line, h-line, i-line, KrF excimer laser beam), ArF excimer laser beam, electron beam, X-ray, molecular beam or ion beam. The generated compounds and mixtures thereof can be appropriately selected and used.

Examples of other photoacid generators that can be used in combination include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, onium salts such as arsonium salts, organic halogen compounds, and organic metal / organic halides. , Photoacid generators having an o-nitrobenzyl-type protecting group, compounds such as iminosulfonates, which generate photosulfonic acids by photolysis, disulfone compounds, diazoketosulfones, diazodisulfone compounds, and the like. .
A group in which an acid is generated by these lights, or a compound in which a compound is introduced into the main chain or side chain of the polymer can also be used in combination.

Furthermore, VNRPillai, Synthesis, (1), 1 (1980), A. Abad etal, Tetrahedron Lett., (47) 4555 (1971), DHR Barton etal, J. Chem. Soc., (C), 329 (1970), Compounds that generate an acid by light as described in US Pat. No. 3,779,778, European Patent 126,712 and the like can also be used in combination.
Among the compounds that decompose by irradiation with actinic rays or radiation to generate an acid, the following general formula (PAG3), general formula (PAG4), general formula (PAG6), or general formula ( And compounds represented by PAG7).

In general formulas (PAG3) and (PAG4), Ar ¹ and Ar ² are the same or different and each represents a substituted or unsubstituted aryl group. Preferable substituents include an alkyl group, a haloalkyl group, a cycloalkyl group, an aryl group, an alkoxy group, a nitro group, a carboxyl group, an alkoxycarbonyl group, a hydroxy group, a mercapto group, and a halogen atom.
R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ are the same or different and each represents a substituted or unsubstituted alkyl group or aryl group. Preferred are aryl groups having 6 to 14 carbon atoms, alkyl groups having 1 to 8 carbon atoms, and substituted derivatives thereof. Preferred substituents are an aryl group having 1 to 8 carbon atoms, an alkyl group having 1 to 8 carbon atoms, a nitro group, a carboxyl group, a hydroxy group, and a halogen atom. An alkoxy group having 1 to 8 carbon atoms, a carboxyl group, and an alkoxycarbonyl group;

Z ⁻ represents a counter anion, such as BF ₄ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , SiF ₆ ²⁻ , ClO ₄ ⁻ , optionally substituted alkanesulfonic acid, perfluoroalkanesulfonic acid, substituted Examples thereof include, but are not limited to, benzenesulfonic acid, naphthalenesulfonic acid, anthracenesulfonic acid, camphorsulfonic acid and the like. Alkanesulfonic acid, perfluoroalkanesulfonic acid, alkyl-substituted benzenesulfonic acid, and pentafluorobenzenesulfonic acid are preferable.
Two of R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ and Ar ¹ and Ar ² may be bonded via a single bond or a substituent.

In the general formulas (PAG6) and (PAG7), R ²⁰⁶ represents a substituted or unsubstituted alkyl group or aryl group. A represents a substituted or unsubstituted alkylene group, alkenylene group, or arylene group. R represents a linear, branched or cyclic alkyl group, or an aryl group which may be substituted.
Specific examples of these include, but are not limited to, the following compounds.

  These photoacid generators that can be used in combination are used in a range of 5% by mass or less, preferably in a range of 2% by mass or less, based on the solid content in the composition.

[3] Other components The positive resist composition of the present invention may further include an acid-decomposable dissolution inhibiting compound, a dye, a plasticizer, a surfactant, a photosensitizer, an organic basic compound, and a development, if necessary. A compound or the like that promotes solubility in the liquid can be contained.

The positive resist composition of the present invention contains a fluorine-based and / or silicon-based surfactant.
The positive resist composition of the present invention contains any one of fluorine surfactants, silicon surfactants and surfactants containing both fluorine atoms and silicon atoms, or two or more thereof.
When the positive resist composition of the present invention contains the above-described surfactant together with the above components, it is particularly effective when the pattern line width is narrower, development defects are further improved, and contact hole resolution is improved. Become better.
As these surfactants, for example, JP-A-62-36663, JP-A-61-226746, JP-A-61-226745, JP-A-62-170950, JP-A-63-34540, JP-A-63-34540 Surfactants described in JP-A-7-230165, JP-A-8-62834, JP-A-9-54432 and JP-A-9-5988 can be mentioned, and the following commercially available surfactants can also be used as they are.
Examples of commercially available surfactants that can be used include F-top EF301 and EF303 (made by Shin-Akita Kasei Co., Ltd.), Florard FC430 and 431 (made by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189, and R08. (Dainippon Ink Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.) A surfactant or a silicon-based surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon surfactant.

The compounding quantity of the said surfactant is 0.001 mass%-2 mass% normally on the basis of solid content in the composition of this invention, Preferably it is 0.01 mass%-1 mass%. These surfactants may be added alone or in some combination.
Specific examples of surfactants that can be used other than the above include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether. , Polyoxyethylene alkyl allyl ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan Sorbitan fatty acid esters such as monooleate, sorbitan trioleate, sorbitan tristearate, polyoxyethylene sorbitan Nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as laurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tristearate Etc.
The amount of these other surfactants is usually 2 parts by mass or less, preferably 1 part by mass or less per 100 parts by mass of the solid content in the composition of the present invention.

  A preferred organic basic compound that can be used in the present invention is a compound that is more basic than phenol. Of these, nitrogen-containing basic compounds having structures represented by the following (A) to (E) are preferred. By using the nitrogen-containing basic compound, the change in performance is small over time from exposure to post-heating.

Here, R ²⁵⁰ , R ²⁵¹ and R ²⁵² are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aminoalkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms, or carbon. A substituted or unsubstituted aryl group of formula 6 to 20, wherein R ²⁵¹ and R ²⁵² may be bonded to each other to form a ring.

(Wherein R ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R ²⁵⁶ are the same or different and represent an alkyl group having 1 to 6 carbon atoms).
Preferred examples include substituted or unsubstituted guanidine, substituted or unsubstituted aminopyridine, substituted or unsubstituted aminoalkylpyridine, substituted or unsubstituted aminopyrrolidine, substituted or unsubstituted indazole, substituted or unsubstituted Pyrazole, substituted or unsubstituted pyrazine, substituted or unsubstituted pyrimidine, substituted or unsubstituted purine, substituted or unsubstituted imidazoline, substituted or unsubstituted pyrazoline, substituted or unsubstituted piperazine, substituted or unsubstituted amino Examples include morpholine, substituted or unsubstituted aminoalkylmorpholine, and mono, di, trialkylamine, substituted or unsubstituted aniline, substituted or unsubstituted piperidine, mono, or diethanolamine. Preferred substituents are amino group, aminoalkyl group, alkylamino group, aminoaryl group, arylamino group, alkyl group, alkoxy group, acyl group, acyloxy group, aryl group, aryloxy group, nitro group, hydroxyl group, cyano group It is.

Preferred compounds include guanidine, 1,1-dimethylguanidine, 1,1,3,3-tetramethylguanidine, 2-aminopyridine, 3-aminopyridine, 4-aminopyridine, 2-dimethylaminopyridine, 4-dimethyl. Aminopyridine, 2-diethylaminopyridine, 2- (aminomethyl) pyridine, 2-amino-3-methylpyridine, 2-amino-4-methylpyridine, 2-amino-5-methylpyridine, 2-amino-6-methyl Pyridine, 3-aminoethylpyridine, 4-aminoethylpyridine, 3-aminopyrrolidine, piperazine, N- (2-aminoethyl) piperazine, N- (2-aminoethyl) piperidine, 4-amino-2,2,6 , 6-tetramethylpiperidine, 4-piperidinopiperidine, 2-iminopiperidine, 1 (2-aminoethyl) pyrrolidine, pyrazole, 3-amino-5-methylpyrazole, 5-amino-3-methyl-1-p-tolylpyrazole, pyrazine, 2- (aminomethyl) -5-methylpyrazine, pyrimidine, 2,4-diaminopyrimidine, 4,6-dihydroxypyrimidine, 2-pyrazoline, 3-pyrazoline, N-aminomorpholine, N- (2-aminoethyl) morpholine, 1,5-diazabicyclo [4,3,0 Nona-5-ene, 1,8-diazabicyclo [5,4,0] undec-7-ene, 2,4,5-triphenylimidazole, tri (n-butyl) amine, tri (n-octyl) amine N-phenyldiethanolamine, N-hydroxyethylpiperidine, 2,6-diisopropylaniline, N-cyclohexyl-N ′ Morpholinoethyl thiourea, but like N- hydroxyethyl morpholine not limited thereto.

Among these, particularly preferred compounds include 1,5-diazabicyclo [4,3,0] non-5-ene, 1,8-diazabicyclo [5,4,0] undec-7-ene, 2,4,5 -Triphenylimidazole, tri (n-butyl) amine, tri (n-octyl) amine, N-phenyldiethanolamine, N-hydroxyethylpiperidine, 2,6-diisopropylaniline, N-cyclohexyl-N'-morpholinoethylthiourea N-hydroxyethylmorpholine.
These nitrogen-containing basic compounds are used alone or in combination of two or more. The usage-amount of a nitrogen-containing basic compound is 0.001-10 mass% normally based on solid content of a composition, Preferably it is 0.01-5 mass%. If it is less than 0.001% by mass, the effect of adding the nitrogen-containing basic compound cannot be obtained. On the other hand, if it exceeds 10% by mass, the sensitivity tends to decrease and the developability of the unexposed area tends to deteriorate.

[4] Method of Using Positive Resist Composition The positive resist composition of the present invention is dissolved in a solvent that dissolves each of the above components and coated on a support. Solvents used here include ethylene dichloride, cyclohexanone, cyclopentanone, 2-heptanone, γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl ether acetate , Propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, toluene, ethyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N, N-dimethyl Formamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofuran, and the like are preferable. Or mixed to use.

  Among these, preferable solvents include 2-heptanone, γ-butyrolactone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, methyl lactate, ethyl lactate , Methyl methoxypropionate, ethyl ethoxypropionate, N-methylpyrrolidone, and tetrahydrofuran.

  Such a positive resist composition of the present invention is applied onto a substrate to form a thin film. The film thickness of this coating film is preferably 0.2 to 1.2 μm. In the present invention, a commercially available inorganic or organic antireflection film can be used if necessary.

As the antireflection film, an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, α-silicon, and an organic film type made of a light absorber and a polymer material can be used. The former requires equipment such as a vacuum deposition apparatus, a CVD apparatus, and a sputtering apparatus for film formation. Examples of the organic antireflection film include a condensate of a diphenylamine derivative and a formaldehyde-modified melamine resin described in JP-B-7-69611, an alkali-soluble resin, a light absorber, and maleic anhydride copolymer described in US Pat. No. 5,294,680. A reaction product of a coalescence and a diamine type light absorbing agent, a resin binder described in JP-A-6-186863 and a methylolmelamine thermal crosslinking agent, a carboxylic acid group, an epoxy group and a light-absorbing group described in JP-A-6-118656. An acrylic resin-type antireflection film in the same molecule, a composition comprising methylol melamine and a benzophenone-based light absorber described in JP-A-8-87115, and a low-molecular light absorber added to a polyvinyl alcohol resin described in JP-A-8-179509 And the like.
Further, as the organic antireflection film, DUV30 series, DUV-40 series manufactured by Brewer Science, AC-2, AC-3 manufactured by Shipley, etc. can be used.

Appropriate use of the resist solution on a substrate (eg, silicon / silicon dioxide coating) used for the manufacture of precision integrated circuit elements (on a substrate provided with the antireflection film if necessary), spinner, coater, etc. A good resist pattern can be obtained by applying through a predetermined coating method, exposing through a predetermined mask, baking and developing. Here, the exposure light is preferably light having a wavelength of 150 nm to 250 nm. Specific examples include a KrF excimer laser (248 nm), an ArF excimer laser (193 nm), an F ₂ excimer laser (157 nm), an X-ray, and an electron beam.

  Examples of the developer include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, primary amines such as ethylamine and n-propylamine, diethylamine, and di-n. -Secondary amines such as butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide. An alkaline aqueous solution of cyclic amines such as pyrrole and pihelidine can be used. Furthermore, an appropriate amount of alcohol or surfactant may be added to the alkaline aqueous solution.

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

<Resin synthesis>
Synthesis Example (1) [Synthesis of Resin 1 as Component (A)]
2-Ethyl-2-adamantyl methacrylate, butyrolactone methacrylate, charged at a ratio (molar ratio) of 40/60, and dissolved in tetrahydrofuran to prepare 100 mL of a 20% solid content solution. To this solution, 2 mol% of V-65 (trade name, manufactured by Wako Pure Chemical Industries, Ltd.) was added to the total number of moles of monomers, and this was added dropwise to 10 mL of tetrahydrofuran heated to 55 ° C. over 2 hours in a nitrogen atmosphere. After completion of dropping, the reaction solution was heated and stirred for 6 hours. After completion of the reaction, the reaction solution was cooled to room temperature, and crystallized and precipitated white powder was collected in 3 L of distilled water.
The composition of the resin determined from C ¹³ NMR was 41/59 (2-ethyl-2-adamantyl methacrylate / butyrolactone methacrylate) in molar ratio. Moreover, the weight average molecular weight of polystyrene conversion calculated | required by GPC measurement was 12700.

Synthesis Examples (4), (5), (8) to (15) [Synthesis of the resin 4, 5, 8-15 as the component (A)]
Resins 4, 5, and 8 to 15 were synthesized in the same manner as in Synthesis Example 1. The composition ratio and weight average molecular weight of the resin are shown in Table 1. The repeating structural units 1, 2, and 3 in Table 1 represent structural units corresponding to the order from the left of the structural unit of each resin described above.

<Synthesis of Photoacid Generator as Component (B)>
The compound of the general formulas (I ′) and (II ′) is prepared by reacting an aryl Grignard reagent such as arylmagnesium bromide with a substituted or unsubstituted phenyl sulfoxide, and converting the resulting triarylsulfonium halide into the corresponding sulfone. A method of salt exchange with an acid, a method of condensation or salt exchange of a substituted or unsubstituted phenyl sulfoxide and a corresponding aromatic compound using an acid catalyst such as methanesulfonic acid / diphosphorus pentoxide or aluminum chloride, and diaryl The iodonium salt and diaryl sulfide can be synthesized by a method such as condensation and salt exchange using a catalyst such as copper acetate.
The sulfonic acid or sulfonate used for the above salt exchange can be obtained by hydrolysis of a commercially available sulfonic acid halide. Hereinafter, synthesis examples 2 and 3 of the photoacid generator as the component (B) are shown. Other photoacid generators used in the following Table 2 can be prepared by the same method or the general method described above. The synthesized one or a commercially available one was used (triphenylsulfonium perfluoro-n-butanesulfonate (I-2) manufactured by Midori Chemical Co., Ltd.).

Synthesis Example (16) [Synthesis of triphenylsulfonium perfluoro-n-octane sulfonate (I-4)]
50 g of diphenyl sulfoxide was dissolved in 800 ml of benzene, and 200 g of aluminum chloride was added thereto and refluxed for 24 hours. The reaction solution was slowly poured into 2 L of water, 400 ml of concentrated hydrochloric acid was added thereto, and the mixture was heated at 70 ° C. for 10 minutes. This aqueous solution was washed with 500 ml of ethyl acetate and filtered, and then 200 g of ammonium iodide dissolved in 400 ml of water was added. The precipitated powder was filtered, washed with water, washed with ethyl acetate, and dried to obtain 70 g of triphenylsulfonium iodide.
17.6 g of triphenylsulfonium iodide was dissolved in 1000 ml of methanol, 12.5 g of silver oxide was added to this solution, and the mixture was stirred at room temperature for 4 hours. The solution was filtered, and a methanol solution containing 25 g of perfluoro-n-octanesulfonic acid was added thereto. The reaction solution was concentrated, and the precipitated oil was dissolved in ethyl acetate, washed with water, dried and concentrated to obtain 20.5 g of the desired product.

Synthesis Example (17) [Synthesis of tri (t-butylphenyl) sulfonium perfluoro-n-butanesulfonate (I-7)]
A mixture of di (t-butylphenyl) sulfide (80 mmol), di (t-butylphenyl) iodonium perfluoro-n-butanesulfonate (20 mmol), and copper benzoate (4 mmol) was stirred at 130 ° C. for 4 hours under a nitrogen stream. . The reaction solution was allowed to cool, 100 ml of ethanol was added thereto, and the precipitate was removed. When the filtrate was concentrated and 200 ml of ether was added thereto, a powder precipitated. This was collected by filtration, washed with ether, and dried to obtain the desired product.

Synthesis Example (18) [Synthesis of a mixture containing (I-27) and (II-1) as main components]
To an aqueous solution of 45% triphenylsulfonium chloride (content is a triarylsulfonium chloride mixture) manufactured by Fluka, 1.1 equivalent of an aqueous solution of tetramethylammonium perfluoro-n-butanesulfonate was added. The precipitated oil was washed with water and dried to obtain the desired product.

[Examples 1, 4, 5, 8-11, 16, 20-23, and Comparative Examples 1-2]
(Preparation and evaluation of positive photoresist composition)
2.0 g of the resin shown in Table 1 synthesized in the above synthesis example, 0.02 g of a photoacid generator shown in Table 2, 0.001 g of an organic basic compound (amine), and 0.004 g of a surfactant were blended. And dissolved in propylene glycol monoethyl ether acetate at a solid content of 14% by mass, respectively, and then filtered through a 0.1 μm microfilter to obtain positive results of Examples 1, 4, 5, 8-11, 16, 20-23. A mold resist composition solution was prepared.
In the case of Comparative Examples 1 and 2, the photoacid generators PAG-A (triphenylsulfonium trifluoromethanesulfonate) and PAG-B (bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate) are used. Prepared positive resist compositions in the same manner as in Examples 1, 4, 5, 8-11, 16, 20-23.

(Evaluation test)
The obtained positive resist composition solution was applied onto a silicon wafer using a spin coater, dried at 135 ° C. for 90 seconds to produce a positive photoresist film of about 0.4 μm, and an ArF excimer laser (wavelength 193 nm). , Using an ISI ArF stepper with NA = 0.6). The heat treatment after the exposure was performed at 120 ° C. for 90 seconds, developed with a 2.38% tetramethylammonium hydroxide aqueous solution, and rinsed with distilled water to obtain a resist pattern profile.
About these, the sensitivity and the resolution were evaluated as follows, and the evaluation results are shown in Table 2.

Sensitivity: Defined with an exposure amount that reproduces a 0.18 μm line and space mask pattern.
Resolution: Defined with the limiting resolution at the above exposure.
Resolving power 1, resolving power 2, shape 1, shape 2: Resolving power when heated and developed immediately after exposure, resist pattern shape as resolving power 1 and shape 1, and after 2 hours after exposure, heating and developing are performed The resolving power and the resist pattern shape at that time were defined as resolving power 2 and shape 2.

(Explanation of Table 2)
<Photo acid generator>
* 1: Mixture containing (I-27) and (II-1) as main components (Synthesis Example 18)
PAG-A; Triphenylsulfonium trifluoromethanesulfonate PAG-B: Bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate <Amine (1) to (4)>
(1): 1,5-diazabicyclo [4.3.0] -5-nonene (2): 2,4,5-triphenylimidazole (3): N-phenyldiethanolamine (4): 2,6-diisopropyl Aniline <Surfactant>
W-1: Megafuck F176 (Dainippon Ink Co., Ltd.) (Fluorine)
W-2: Megafuck R08 (Dainippon Ink Co., Ltd.) (fluorine and silicone)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.)
W-4: Troisol S-366 (manufactured by Troy Chemical Co., Ltd.) (silicon-based)

As is clear from the results in Table 2, the positive resist composition of the present invention has sufficient sensitivity and resolution for exposure at a wavelength of 193 nm, and there is almost no change in performance over time from exposure to post-heating.
On the other hand, Comparative Examples 1 and 2, which do not use the photoacid generator specified in the present invention, are inferior in resolving power as compared with the examples, and have a large performance change with time from exposure to post-heating.

Claims (6)

(A) A resin containing a repeating structural unit represented by the following general formula (I) and a repeating structural unit represented by the following general formula (II), wherein the dissolution rate in an alkali developer is increased by the action of an acid; B) A positive resist composition comprising a compound represented by the following general formula (I ′) that generates sulfonic acid upon irradiation with actinic rays or radiation, and a fluorine-based and / or silicon-based surfactant. object.

In the above general formula (I):
R ₀₁ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
R ₀₂ represents an alkyl group having 1 to 4 carbon atoms.
In the above general formula (II):
R ₀₁ each independently represents a hydrogen atom or a methyl group.
W represents a single bond.
Rb, Rc, Rd, Re, and Rf in Lc each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, but the number of alkyl groups having 1 to 4 carbon atoms is at most three.
Ra represents a single bond and is bonded to W.
m and n each independently represents an integer of 0 to 2, and m + n is 2.

In the above general formula (I ′):
R _{1 to} R ₁₅ are the same or different and are a hydrogen atom, linear, branched or cyclic alkyl group, linear, branched or cyclic alkoxy group, hydroxyl group, halogen atom, or —S—R ₃₈ group. Represents. _R38 represents a linear, branched or cyclic alkyl group or an aryl group.
Two or more of R _{1 to} R ₁₅ may be bonded to form a ring containing one or more selected from a single bond, carbon, oxygen, sulfur, and nitrogen.
X ^- is, R ^F SO ₃ ^- represents a. Here, R ^F is a fluorine-substituted linear alkyl group represented by CF ₃ (CF ₂ ) y (where y is an integer of 1 to 9) . The positive resist composition according to claim 1 , wherein y is an integer of 1 to 7. The positive resist composition according to claim 1 , wherein y is an integer of 1 to 4. The fluorine-containing and / or silicon surfactants, based on the total solids of the positive resist composition, according to claim 1 to 3 any one of which is characterized in that it contains 0.001 mass% The positive resist composition as described in 1. above. The positive resist composition according to any one of claims 1-4, characterized in that it further contains a nitrogen-containing basic compound. The positive resist composition according to any one of claims 1-5, pattern forming method forming a resist film from exposure to the resist film, characterized by development.