JPH10239848A - Positive photoresist composition for exposure to far ultraviolet rays - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the positive photosensitive composition satisfying necessary characteristics, such as sensitivity and resolution and pattern profiles in using it for exposure to far ultraviolet rays, especially, excimer laser beams by using a combination of a specified acrylic resin with a photo-acid-generator. SOLUTION: This positive photoresist composition for exposure to far ultraviolet rays contains the resin having repeating units derived from a monomer represented by the formula in which R1 is an H atom or a methyl group; each of R2 -R4 is an H atom or an alkyl group; each of R5 and R6 is an H atom or an alkyl or XR7 group; R7 is an H atom or an alkyl group; X is an O or S atom; A is a simple bond or one group selected from an optionally substituted alkylene group and the like and >=2 combinations of them; (m) is 1, 2, or 3; (n) is 0, 1, or 2; and m+n=3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a super microlithography process such as the manufacture of a super LSI and a high capacity micro chip, and other photofabrication processes. More specifically, excimer laser
The present invention relates to a positive photoresist composition capable of forming a high-definition pattern using a far ultraviolet region including light.

[0002]

2. Description of the Related Art In a photofabrication process such as lithographic printing, manufacture of semiconductors such as ICs, and manufacture of circuit boards such as thermal heads, spin coating is performed on a substrate such as a semiconductor wafer, glass, ceramic, or metal. Alternatively, apply a photoresist to a thickness of 0.5 to 2.5 μm by a roller coating method, heat it, dry it, bake a circuit pattern or the like with an active light such as ultraviolet rays through an exposure mask, and after exposing as necessary. After baking, development is performed to form a resist image. Further, pattern processing on the substrate can be performed by etching using this image as a mask. In many cases, an alkali-soluble resin and a photosensitive material are generally used in combination as a positive photoresist composition, and in particular, a composition containing a combination of a novolak phenol resin and a naphthoquinonediazide compound is used. Positive photoresist composed of novolak resin and quinonediazide compound has high resistance to plasma etching, inhibition of dissolution of naphthoquinonediazide compound, disappearance of dissolution inhibition ability due to carboxylic acid by light irradiation, and consequent alkali of novolak resin. Numerous developments and commercializations have been made for the advantageous property of improving the solubility, and sufficient results have been achieved in line width processing down to about 0.8 μm to 2 μm.

[0003] However, the degree of integration of integrated circuits is increasing more and more, and in the manufacture of semiconductor substrates such as VLSI, processing of ultrafine patterns having a line width of less than half a micron is required. Have been. In order to meet the need, the wavelength used in an exposure apparatus used for photolithography is becoming shorter and shorter, and now it is considered to use excimer laser light (XeCl, KrF, ArF, etc.) having a short wavelength among far ultraviolet rays. Up to now.
In lithography pattern formation in this wavelength region, light is difficult to reach the bottom of the resist due to strong absorption of novolak and naphthoquinonediazide in the far ultraviolet region, and only a low-sensitivity, tapered pattern can be obtained. Novolak naphthoquinonediazide compound resists are not sufficient.

One of the means for solving this problem is a chemically amplified resist composition described in US Pat. No. 4,491,628 and European Patent No. 249,139. The chemically amplified positive resist composition generates an acid in the exposed area by irradiation with actinic light such as far ultraviolet rays, and the reaction using the acid as a catalyst dissolves the actinic light irradiation area and the non-irradiation area in a developing solution. A composition designed to change the properties and form a pattern on a substrate.

In general, chemically amplified resists can be broadly classified into three types: so-called two-component, 2.5-component and three-component resists. 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 a group (also referred to as an acid-decomposable group) which decomposes under the action of an acid to increase the solubility of the resin in an alkaline developer in the molecule. The 2.5-component system further contains a low-molecular compound having an acid-decomposable group in such a two-component system. The three-component system contains a photoacid generator, an alkali-soluble resin, and the above low molecular compound.

As an example of such a combination of a photoacid generator and a resin whose solubility is changed by an acid, a combination of an acetal or an O, N-acetal compound (Japanese Patent Laid-Open No.
No. 8-89003), a combination with an orthoester or an amide acetal compound (JP-A-5120714).
), A combination with a polymer having an acetal or ketal group in the main chain (JP-A-53-133429), a combination with an enol ether compound (JP-A-55-12995).
No. 5), a combination with an N-acyliminocarbonate compound (JP-A-55-126236), a combination with a polymer having an orthoester group in the main chain (JP-A-56-17345).
), A combination with a tertiary alkyl ester compound (JP-A-60-3625), a combination with a silyl ester compound (JP-A-60-10247), and a combination with a silyl ether compound (JP-A-60-6060). -37549, JP-A-60-112446) and the like. These have high photosensitivity because the quantum yield exceeds 1 in principle.

Similarly, systems which are stable under aging at room temperature, but are decomposed by heating in the presence of an acid and solubilized in alkali are disclosed in, for example, JP-A-59-45439 and JP-A-60-3625. JP-A-62-229242, JP-A-63-27829, JP-A-63-36240,
JP-A-63-250542, Polym.Eng.Sce., Vol. 23,
1012 (1983); ACS.Sym. 242, 11 (1984); Semi
conductor World 1987, November, p. 91; Macromolecul
es, Volume 21, p. 1475 (1988); SPIE, Volume 920, p. 42 (1988)
And the like, and a combination of a photoacid generator described above and an ester or carbonate compound of a tertiary or secondary carbon (for example, t-butyl, 2-cyclohexenyl). These systems also have high sensitivity and have naphthoquinonediazide /
Since the absorption in the far ultraviolet region is smaller than that of the novolak resin system, it can be an effective system for shortening the wavelength of the light source.

In particular, KrF excimer laser 248
A resist composition using a polymer in which an acetal group or a ketal group is introduced as a protective group into a hydroxystyrene-based polymer having a small light absorption when using light of nm is proposed. For example, JP-A-2-141636, JP-A-2-19847, JP-A-4-219957, and JP-A-5
Japanese Patent Publication No. -281745 is an example thereof. In addition, similar compositions using a t-butoxycarbonyloxy group or a p-tetrahydropyranyloxy group as an acid-decomposable group are disclosed in JP-A-2-209977, JP-A-3-206458,
And the like, but when using an ArF excimer laser as a light source, their sensitivity is low because the absorbance is still too large. In addition, there are other disadvantages associated therewith, such as deterioration of resolution, deterioration of focus tolerance, deterioration of pattern profile, and the like, and many points still need improvement.

Accordingly, a photoresist composition for an ArF light source is a photoresist composition in which a (meth) acrylic resin having a lower absorption than a partially hydroxylated styrene resin is combined with a compound capable of generating an acid by light. Resist compositions have been proposed. For example, JP-A-7-1
No. 99467 and No. 7-252324. Among them, JP-A-6-289615 discloses a resin in which a tertiary carbon organic group is ester-bonded to oxygen of a carboxyl group of acrylic acid, and JP-A-7-234511 discloses a resin in which dimethyl is substituted by oxygen of a carboxyl group of acrylic acid. A copolymer resin of a structural unit having an ester bond of a secondary carbon group and a structural unit having an ester bond of an alicyclic group is disclosed. These have light absorbing aryl groups in the carbon substituents and are poor in acid decomposability even if they are improved in light transmission to an ArF light source, and are still sufficiently satisfactory for the purpose. A material exhibiting excellent characteristics has not been obtained.

Here, the photo-acid generator used in the above-mentioned positive type chemically amplified resist will also be described with reference to the prior art. Known photoacid generators include N-imidosulfonate, N-oximesulfonate, o-nitrobenzylsulfonate, trismethanesulfonate of pyrogallol, and the like. Further, sulfonium, iodonium and the like are known as having high photolytic efficiency and excellent image forming properties. The their pairs salts PF ₆ ^-, A
sF ₆ ^-, SbF ₆ ^- perfluoro Lewis acid salt or the like, is trifluoromethanesulfonic acid anion, toluenesulfonic acid anion are known. Further, benzenesulfonic acid, naphthalenesulfonic acid or anthracenesulfonic acid having one linear alkyl group or one alkoxy group is also disclosed from the viewpoint of improving the solvent solubility. However, none of them is sufficient to solve the drawbacks such as contamination by a counter anion element and thinning of the resist pattern with the passage of time from exposure to heat treatment, and further improvement in sensitivity and resolution is desired.

[0011]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the problem of the performance improvement technology inherent in microphotofabrication using far ultraviolet light, particularly excimer laser light. An object of the present invention is to develop a resist composition which satisfies required characteristics such as sensitivity, resolution, and pattern profile for use of a short wavelength light source. Among them, the main object of the present invention is to develop a photoresist composition which has a low absorbance particularly to an ArF excimer laser light source and therefore has high sensitivity, and also has excellent resolution and pattern profile.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on constituent materials of a resist composition in a positive-type chemical amplification system, and as a result, they have found that a structural unit having a specific structure and having an acid-decomposable substituent is contained (meta-type). ) We have found that the object can be achieved by the combination of an acrylic resin and a photoacid generator, leading to the present invention. That is, the above object is achieved by a method having the following configuration.

1. In a positive photoresist composition containing a resin that decomposes under the action of an acid to increase the solubility in alkali and a compound that generates an acid by irradiation with actinic rays or radiation, the solubility in an alkali decomposes under the action of the acid. A positive photoresist composition for deep ultraviolet exposure, wherein the increasing resin is a polymer containing a monomer represented by the following general formula [I] as one of the repeating units.

Embedded image (Wherein, R ₁ represents a hydrogen atom or a methyl group, and R _{2 to} R
₄ may be the same or different and represents a hydrogen atom or an alkyl group. R ₅ and R ₆ may be the same or different and represent a hydrogen atom, an alkyl group or an XR ₇ group, wherein R ₇ is a hydrogen atom or an alkyl group, and X is an oxygen atom or a sulfur atom. A is a single bond, an alkylene group, a substituted alkylene group,
Ether group, ester group, thioether group, carbonyl group, amide group, sulfonamide group. It represents one group selected from the group consisting of a urethane group and a urea group, or a group obtained by combining two or more thereof. m represents 1, 2 or 3, n represents 0, 1 or 2, and the sum of m and n represents 3. ) 2. A resin which is decomposed by the action of an acid to increase the solubility in alkali is a copolymer having a repeating unit of a monomer represented by the general formula [I] and a monomer having an aliphatic cyclic hydrocarbon moiety in the molecule Wherein 1. 4. The positive photoresist composition for deep ultraviolet exposure according to item 1. 3. The wavelength of the actinic ray or radiation to be exposed is 170 to 2
3. The positive photoresist composition for deep ultraviolet exposure according to 1 or 2, wherein the thickness is 20 nm. 4. (1) The resin as described in (1) above, wherein the resin further contains a repeating structural unit having a group that is decomposed by the action of an acid to increase the solubility in an alkaline developer. Or 2. 4. The positive photoresist composition for deep ultraviolet exposure according to item 1. 5. 3. The positive for ultraviolet ray exposure according to any one of the above-mentioned items 1 to 3, wherein the optical density per 1 micron of the thickness of the coating is 1.0 or less with respect to actinic light having a wavelength of 193 nm. -Type photoresist composition.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The compounds used in the present invention are described below.
This will be described in detail. First, it is decomposed by the action of acid,
Resins that increase solubility in alkaline developers, ie
General formula (I) is included as one of the repeating structural units
Will be described. In the general formula (I), R₁
Represents a hydrogen atom or a methyl group;_Two~ R _FourIs the same
It may be different and represents a hydrogen atom or an alkyl group. Also,
R_FiveAnd R ₆May be the same or different,
Kill group or XR₇R represents a group₇Is a hydrogen atom or alk
X is an oxygen or sulfur atom R_Two~ R
₇Examples of the alkyl group represented by are a methyl group, an ethyl group,
Propyl group, isopropyl group, butyl group, isobutyl group,
Lower alkyl groups such as sec-butyl group are preferred, and more preferred.
Or methyl, ethyl, propyl, isopropyl
Group, butyl group, more preferably methyl group, ethyl
Group. m is 1, 2 or 3, n is 0, 1 or
2, the sum of m and n represents 3. A is a single bond, alkylene
Group, substituted alkylene group, ether group, ester group,
And a sulfonamide group. Urethane and urea groups
One group selected from the group consisting of
Represents a group combining the above. An alkylene group of A,
Examples of the alkylene group include groups shown below.
it can.

[0015]

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R and R 'each represent a hydrogen atom, an alkyl group, a substituted alkyl group, a halogen atom, a hydroxyl group or an alkoxy group, and they may be the same or different. Here, the alkyl group is preferably a lower alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group,
More preferably, they are a methyl group, an ethyl group, a propyl group, or 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. a represents an integer of 1 to 10.

A represents a single bond or
One group selected from an alkylene group, a substituted alkylene group, an ether group, an amide group, a urea group, a urethane group, and an ester group, or a group obtained by combining two or more groups is particularly preferable. Here, the alkylene group and the substituted alkylene group are preferably an alkylene group having 1 to 4 carbon atoms, specifically, a methylene group, an ethylene group, a propylene group, a butylene group, a methyl-substituted methylene group, a dimethyl-substituted methylene group,
Examples include a methyl-substituted ethylene group, a dimethyl-substituted ethylene group, a methyl-substituted propylene group, and a dimethyl-substituted propylene group. Preferred examples of the monomer represented by the general formula [I] below include monomers represented by the general formulas [IA] to [IK].

[0018]

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[0019]

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In the above general formula, R _{2 to} R ₇ , R,
R ′, n, m, and a have the same meanings as above. b is 1
Represents the number 3. Specific examples of the monomer represented by the general formula [I] are shown below. However, these do not limit the content of the present invention.

[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

Embedded image The monomer represented by the general formula [I] is composed of a carboxylic acid having a radically polymerizable carbon-carbon double bond in the molecule and a 2-carboxylic acid.
Hydroxylactones were converted to Angew. Chem. Int.Ed. Eng.
l., 1978, 17,522, by esterification or by reacting the corresponding carboxylic acid chloride with 2-hydroxylactones under basic conditions.

The resin in the positive photoresist composition of the present invention may contain a group represented by the above general formula [I],
It is preferable to include a repeating structural unit having an aliphatic cyclic hydrocarbon site in the molecule. Thereby, the dry etching resistance of the positive photoresist can be increased. Examples of the repeating structural unit having an aliphatic cyclic hydrocarbon moiety in the molecule include a repeating structural unit represented by the following general formula [III] or [IV].

[0029]

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[0030]

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R ₈ in the general formula [III] is a monovalent aliphatic cyclic hydrocarbon group. Specifically, an adamantyl group, 2-
A methyl-2-adamantyl group, a norbornyl group, a boronyl group, an isobornyl group, a tricyclodecanyl group, a dicyclopentenyl group, a nobornane epoxy group, a menthyl group,
Examples include an isomenthyl group and a neomenthyl group. R ₉ is a hydrogen atom or a methyl group. General formula (I
V], R ₁₀ is a linking group having a divalent aliphatic cyclic hydrocarbon site. G is -COOH, -OH, -COOR
₁₁ or an -OR _11. R ₁₁ is a tertiary alkyl group, a tetrahydropyranyl group, a tetrahydrofuranyl group, —CH ₂
OR ₁₂ or an -CH (CH ₃₎ OR _12. R ₁₂ represents an alkyl group. Examples of the aliphatic cyclic hydrocarbon moiety contained in the linking group of R ₁₀ include the following structures.

[0032]

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Further, the linking group in R ₁₀ that connects the alicyclic hydrocarbon moiety and an ester group or the alicyclic hydrocarbon moiety and G groups may be a single bond, an alkylene group, an ether group, a thioether group , Carbonyl group,
Examples thereof include one group selected from an ester group, an amide group, a sulfonamide group, and the like, or a group obtained by combining two or more groups.

-COOR₁₁Group or -OR₁₁In the base
R₁₁Is a tertiary alkyl such as a t-butyl group and a t-amyl group.
Group, tetrahydropyranyl group, tetrahydrofuranyl
Group, -CH (CH_Three) OCH_TwoCH_ThreeGroup, -CH (CH
_Three) OCH_TwoCH (CH_Three) _Two1-alkoxy groups such as
Chill group, -CH_TwoOCH_ThreeGroup, -CH_TwoOCH_TwoCH _Three
Decomposes by the action of acids such as alkoxymethyl groups
Represents a substituent.

In the above resin, the content of the repeating structural unit containing the group represented by the general formula [I] is preferably from 5 mol% to 80 mol%, more preferably from 10 mol% to 70 mol%, based on all repeating units. Mol%. When the amount is less than 5 mol%, the effects of the present invention are hardly exhibited, which is not preferable. 80 mol%
Exceeding the range is undesirable because the dry etching resistance tends to deteriorate. The content of the repeating structural unit having an aliphatic cyclic hydrocarbon moiety in the molecule in the resin is preferably from 95 to 20 mol%, more preferably from 90 to 30 mol%, based on all repeating units.

The resin according to the present invention further decomposes by the action of an acid in addition to the group represented by the general formula [I] and the repeating structural unit having an aliphatic cyclic hydrocarbon moiety, and is soluble in an alkali developing solution. It is preferable to contain a group (also referred to as an acid-decomposable group) that increases the value. Thereby, the effect of improving the sensitivity becomes more remarkable. As such an acid-decomposable group, the above-mentioned —COOR ₁₁ , —OR ₁₁ , 3-oxocyclohexyl group or 2-oxocyclohexyl group is preferable. Specific examples include the following repeating structural units corresponding to existing monomers.

For example, t-butyl acrylate, t-butyl methacrylate, t-amyl acrylate, t-amyl methacrylate, tetrahydrofuranyl acrylate, tetrahydrofuranyl methacrylate, tetrahydropyranyl acrylate, tetrahydropyranyl methacrylate, alkoxymethyl acrylate, alkoxymethyl methacrylate , 1-alkoxyethyl methacrylate, and the like.

In the above resin, the content of the repeating structural unit based on such a monomer having an acid-decomposable group is determined by the total mole of the repeating structural unit having the group represented by the above general formula [I]. It is preferably at most 99 mol%, more preferably at most 90 mol%, even more preferably at most 80 mol%, based on the number. If it exceeds 99 mol%, the effect of the present invention is not sufficiently exhibited, so that it is not preferable.

Such a resin can be copolymerized as a repeating unit with the following monomers as long as the effects of the present invention can be effectively obtained, but are not limited thereto. . Thereby, the performance required for the resin, particularly (1) solubility in a coating solvent, (2) film-forming property (glass transition point), (3) alkali developability, (4)
Fine adjustment of film loss (hydrophilic / hydrophobic, alkali-soluble group selection), (5) adhesiveness of the unexposed portion to the substrate, and (6) dry etching resistance can be performed.

Examples of such a comonomer include acrylates, methacrylates, and the like.
Examples thereof include compounds having one addition-polymerizable unsaturated bond selected from acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, and the like.

Specifically, for example, acrylic esters such as alkyl (the alkyl group has 1 to 1 carbon atoms)
Acrylates (for example, methyl acrylate, ethyl acrylate, propyl acrylate, amyl acrylate, cyclohexyl acrylate, ethylhexyl acrylate, octyl acrylate, acrylate-
t-octyl, chloroethyl acrylate, 2-hydroxyethyl acrylate 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, Tetrahydrofurfuryl acrylate, etc.);

Methacrylic esters such as alkyl (preferably having 1 to 10 carbon atoms in the alkyl group) methacrylate (eg, 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, etc.);

Acrylamides, for example, acrylamide, N-alkylacrylamide, wherein the alkyl group has 1 to 10 carbon atoms, for example, methyl, ethyl, propyl, butyl, t-butyl, heptyl, octyl Group, cyclohexyl group, hydroxyethyl group, etc.), N, N-dialkylacrylamide (alkyl group having 1 to 10 carbon atoms, for example, methyl group, ethyl group, butyl group, isobutyl group, ethylhexyl group, Cyclohexyl group, etc.), N-
Hydroxyethyl-N-methylacrylamide, N-2
-Acetamidoethyl-N-acetylacrylamide and the like;

Methacrylamides, for example, methacrylamide, N-alkyl methacrylamide (the alkyl group having 1 to 10 carbon atoms, for example, methyl, ethyl, t-butyl, ethylhexyl, hydroxyethyl, cycloethyl) Groups, etc.), N, N-dialkylmethacrylamide (an alkyl group includes an ethyl group, a propyl group, a butyl group, etc.), N-hydroxyethyl-N-methylmethacrylamide and the like;

Allyl compounds such as allyl esters (eg, allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate), allyloxy Ethanol, etc .;

Vinyl ethers such as alkyl vinyl ethers (eg, hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethylhexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethyl Butyl vinyl ether, hydroxyethyl vinyl ether, diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, etc.);

Vinyl esters such as vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxy acetate, vinyl butoxy acetate, Vinyl acetoacetate, vinyl lactate, vinyl-β-phenylbutyrate, vinylcyclohexylcarboxylate and the like;

Dialkyl itaconates (eg, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, etc.); dialkyl esters of maleic acid or fumaric acid (eg, dimethyl maleate, dibutyl fumarate, etc.) or monoalkyl esters; acrylics acid,
Examples include methacrylic acid, crotonic acid, itaconic acid, maleic anhydride, maleimide, acrylonitrile, methacrylonitrile, maleilenitrile, and the like. In addition, any addition-polymerizable unsaturated compound copolymerizable with the repeating unit containing the group represented by the general formula [I] may be used. The content of the repeating unit based on the additional monomer in the resin is based on the total number of moles of the repeating structural unit represented by the general formula [I] and the repeating structural unit having an aliphatic cyclic hydrocarbon site. Is preferably 99 mol% or less, more preferably 9 mol% or less.
0 mol% or less, more preferably 80 mol% or less. If it exceeds 99 mol%, the effect of the present invention is not sufficiently exhibited, so that it is not preferable.

The weight average molecular weight of the resin according to the present invention is preferably from 2,000 to 200,000. When the weight average molecular weight is less than 2,000, heat resistance and dry etching resistance are deteriorated.
If it exceeds 000, a very unfavorable result such as deterioration of the developability and an extremely high viscosity will result in deterioration of the film-forming property.

As described above, the resin according to the present invention has substantially no light-absorbing group in the far ultraviolet region in both the main chain and the side chain. Irradiating light, which results in high sensitivity and a good pattern profile. Low transmission density is a necessary condition, which does not immediately lead to excellent resist properties, and it is needless to say that other influencing factors are involved, but the resin according to the present invention meets this requirement. Meets

The resin according to the present invention can be synthesized by an ordinary method such as radical polymerization using an azo compound or the like as an initiator. The positive photoresist composition of the present invention mainly contains the above resin and a photoacid generator. The addition amount of the above resin in the entire composition is 40 to 99% by weight, preferably 50 to 97% by weight, based on the whole resist solids.

Next, the photoacid generator in the positive photoresist composition of the present invention will be described. The photoacid generator needs to satisfy two properties. That is,
(1) transparency to exposure light (provided that there is no light bleaching property); and (2) sufficient photodegradability to ensure resist sensitivity. However, at present, there is no clear guideline for molecular design that satisfies such contradictory requirements. For example, the following examples can be given. That is, JP-A-7-25846 and JP-A-7-2823
7, JP-A-7-92675, JP-A-8-2
Aliphatic alkulfonium salts having a 2-oxocyclohexyl group described in JP-A-7102, and N-
Hydroxysuccinimide sulfonates and the like can be mentioned. Furthermore, J. Photopolym. Sci. Techn
ol., Vol 7, No. 3, p 423 (1994) and the like, and sulfonium salts represented by the following general formula (VI), disulfones represented by the following general formula (VII), and the following general formula The compound represented by (VIII) can be mentioned.

[0053]

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Here, R _{12 to} R ₁₅ each represent an alkyl group or a cyclic alkyl group. These may be the same or different from each other. Further, N-hydroxymaleimide sulphonates represented by the following general formula (IX) are also suitable.

[0055]

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Here, R ₁₆ and R ₁₇ may be the same or different and represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group. R ₁₆ and R ₁₇ may be bonded via an alkylene group to form a ring. R ₁₈ represents an alkyl group, a perfluoroalkyl group, a cycloalkyl group or a substituted camphor. Such N-hydroxymaleimide sulphonates are particularly preferred in terms of photosensitivity.

The alkyl group having 1 to 6 carbon atoms for R ₁₆ and R ₁₇ in the general formula (IX) includes a methyl group,
Ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group,
An n-hexyl group can be mentioned. Among them, preferred are a methyl group, an ethyl group and a propyl group, and a methyl group and an ethyl group are more preferred. Examples of the cycloalkyl group having 6 or less carbon atoms include a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group. Preferably, they are a cyclopentyl group and a cyclohexyl group. R ₁₆ ,
Examples of the case where R ₁₇ forms a ring with each other by an alkylene chain include a case where a cyclohexyl group, a norbornyl group, and a tricyclodecanyl group are formed.

As the alkyl group for R ₁₈ , a straight-chain C 1-20 group such as a methyl group, an ethyl group or a propyl group may be used.
Alkyl groups, isopropyl groups, isobutyl groups, t
Examples thereof include a branched alkyl group having 1 to 20 carbon atoms such as an tert-butyl group and a neopentyl group. It is preferably a linear or branched alkyl group having 1 to 16 carbon atoms, and more preferably 4 to 15 carbon atoms.
Linear or branched alkyl groups. Examples of the perfluoroalkyl group include a trifluoromethyl group, a pentafluoroethyl group and other straight-chain carbon atoms having 1 to 20 carbon atoms.
And a branched perfluoroalkyl group having 1 to 20 carbon atoms such as a perfluoroalkyl group, a heptafluoroisopropyl group, and a nonafluoro tert-butyl group. Preferably, it is a linear or branched perfluoroalkyl group having 1 to 16 carbon atoms. As the cyclic alkyl group, a monocyclic cyclic alkyl group such as a cyclopentyl group and a cyclohexyl group, a decalyl group,
Examples thereof include a plurality of cyclic alkyl groups such as a norbornyl group and a tricyclodecanyl group.

The amount of such a photoacid generator added to the composition is 0.1 to 0.1% of the total solid content of the positive photoresist composition.
To 20% by weight, more preferably 0.5 to 15% by weight.
%, More preferably 1 to 10% by weight.

In the positive photoresist composition of the present invention, the following photoacid generator may be used in addition to the above photoacid generator.

The amount of the photoacid generator which can be used in combination as described below in the composition is 2% by weight or less, more preferably 1% by weight in the solid content of the whole positive photoresist composition.
The following is good. For example, SISchlesinger, Photogr.Sci.E
ng., 18,387 (1974), TSBal etal, Polymer, 21,423 (198
0) etc., U.S. Pat.No.4,069,055
No. 4,069,056, Re 27,992, Japanese Patent Application No. 3-140,14
Ammonium salts described in No. 0 etc., DCNecker etal, Macr
omolecules, 17, 2468 (1984), CSwen et al, Teh, Proc. Co.
nf.Rad.Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat.Nos. 4,069,055, 4,069,056, phosphonium salts described in JVCrivello et al., Macromorecules, 10 (6), 1307.
(1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, U.S. Patent No. 339,049, No. 410,201.
No., JP-A-2-150,848, iodonium salts described in JP-A-2-296,514, etc., JVCrivello et al., Polymer J. 17,7
3 (1985), JVCrivello et al. J. Org.Chem., 43, 3055 (19
78), WRWatt et al, J. Polymer Sci., Polymer Chem. E
d., 22, 1789 (1984), JVCrivello etal, Polymer Bul
l., 14,279 (1985), JVCrivello etal, Macromorecules,
14 (5), 1141 (1981), JVCrivelloetal, J. PolymerSci.,
Polymer Chem.Ed., 17,2877 (1979), EP 370,693
No. 3,902,114, No. 233,567, No. 297,443, No.
Nos. 297,442; U.S. Pat.Nos. 4,933,377; 161,811;
No. 410,201, No. 339,049, No. 4,760,013, No. 4,73
No. 4,444, No. 2,833,827, Dokoku Patent No. 2,904,626,
The sulfonium salts described in JP-A-3,604,580 and JP-A-3,604,581, etc., JVCrivello et al., Macromorecules, 10 (6), 1307
(1977), JVCrivello et al., J. PolymerSci., Polymer C
hem.Ed., 17,1047 (1979) and the like,
CSWen etal, Teh, Proc.Conf.Rad.Curing ASIA, p478 To
kyo, Oct (1988) and the like, onium salts such as arsonium salts, U.S. Patent No. 3,905,815, JP-B-46-4605, JP-A-48-36281, JP-A-55-32070, JP-A-60 -239736
No., JP-A-61-169835, JP-A-61-169837, JP-A-61-169837
No. 62-58241, JP-A-62-212401, JP-A-63-70243,
Organic halogen compounds described in JP-A-63-298339, etc.
Meier et al., J. Rad. Curing, 13 (4), 26 (1986), TPGillet
al, Inorg.Chem., 19, 3007 (1980), D. Astruc, Acc.
s., 19 (12), 377 (1896), and organometallic / organic halides described in JP-A-2-14145, S. Hayase et al., J. Polymer
Sci., 25, 753 (1987), E. Reichmanis et al., J. Pholimer S
ci., PolymerChem. Ed., 23, 1 (1985), QQZhu et al., J. Pho
tochem., 36, 85, 39, 317 (1987), B. Amit etal, Tetrahedro
n Lett., (24) 2205 (1973), DHR Barton et al., J. Chem So
c., 3571 (1965), PMCollins et al., J. Chem.SoC., Perkin
I, 1695 (1975), M. Rudinsteinetal, Tetrahedron Lett.,
(17), 1445 (1975), JWWalker etal J. Am. Chem. Soc., 11
0,7170 (1988), SCBusman et al., J. Imaging Technol., 1
1 (4), 191 (1985), HMHoulihan et al, Macormolecules, 2
1,2001 (1988), PMCollins et al., J. Chem. Soc., Chem. Com
mun., 532 (1972), S. Hayase et al, Macromolecules, 18, 179.
9 (1985), E. Reichmanis et al., J. Electrochem. Soc., Soli
d State Sci.Technol., 130 (6), FMHoulihan et al, Mac
romolcules, 21, 2001 (1988), European Patent No. 0290,750, ibid.
46,083, 156,535, 271,851, 0,388,343
No. 3,901,710, 4,181,531, JP-A-60-198538, JP-A-53-133022, etc., a photoacid generator having an o-nitrobenzyl-type protecting group, M.TUNOOKA
etal, Polymer Preprints Japan, 35 (8), G. Berner etal,
J.Rad.Curing, 13 (4), WJMijs etal, Coating Techno
l., 55 (697), 45 (1983), Akzo, H. Adachi et al, Polymer
Preprints, Japan, 37 (3), European Patent Nos. 0199,672 and 8451
No. 5, No. 199,672, No. 044,115, No. 0101,122, U.S. Pat.Nos. 618,564, 4,371,605, 4,431,774
No., JP-A-64-18143, JP-A-2-245756, Japanese Patent Application No. 3-14
Compounds which generate sulfonic acid upon photolysis, such as iminosulfonate described in JP-A No. 61-166.
And the disulfone compound described in JP-A-544.

Further, a group that generates an acid by these lights,
Alternatively, a compound having a compound introduced into a main chain or a side chain of a polymer, for example, MEWoodhouse et al., J. Am. Chem.
c., 104, 5586 (1982), SPPappas et al, J. Imaging Sc
i., 30 (5), 218 (1986), S. Kondoetal, Makromol.Chem., Ra
pid Commun., 9,625 (1988), Y.Yamada et al., Makromol.C
hem., 152, 153, 163 (1972), JVCrivello etal, J. Polym
erSci., Polymer Chem. Ed., 17,3845 (1979), U.S. Patent No. 3,849,137, Dokoku Patent No. 3,914,407, JP-A-63-266.
No. 53, JP-A-55-164824, JP-A-62-69263, JP-A-Showa
63-146038, JP-A-63-163452, JP-A-62-153853
And the compounds described in JP-A-63-146029 and the like can be used.

Further, VNRPillai, Synthesis, (1), 1 (198
0), A. Abad etal, Tetrahedron Lett., (47) 4555 (1971),
DHR Barton et al., J. Chem. Soc., (C), 329 (1970), U.S. Pat. No. 3,779,778, EP 126,712, and the like, can also be used compounds which generate an acid by light.

Among the above compounds which can be used together and which generate an acid by being decomposed by irradiation with actinic rays or radiation, those which are particularly effectively used are described below. (1) The following general formula (PAG) substituted with a trihalomethyl group
The oxazole derivative represented by 1) or the general formula (PA)
An S-triazine derivative represented by G2).

[0065]

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In the formula, R ²⁰¹ represents a substituted or unsubstituted aryl group or alkenyl group, and R ²⁰² represents a substituted or unsubstituted aryl group, alkenyl group, alkyl group or —C (Y) ₃ . Y represents a chlorine atom or a bromine atom. Specific examples include the following compounds, but the present invention is not limited thereto.

[0067]

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[0068]

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[0069]

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(2) An iodonium salt represented by the following formula (PAG3) or a sulfonium salt represented by the following formula (PAG4).

[0071]

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In the formula, Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aryl group. Here, preferred 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,
And mercapto groups and halogen atoms.

R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ each independently represent a substituted or unsubstituted alkyl group or aryl group. Preferably, an aryl group having 6 to 14 carbon atoms, 1 to 8 carbon atoms
And substituted derivatives thereof. Preferred substituents are those having 1 to 8 carbon atoms for the aryl group.
And an alkyl group having 1 to 8 carbon atoms, a nitro group, a carboxyl group, a hydroxy group and a halogen atom, and an alkyl group is an alkoxy group having 1 to 8 carbon atoms, a carboxyl group and an alkoxycarbonyl group. .

[0074] Z ^- represents a counter anion, CF ₃ SO ₃ ^-
And the like, such as perfluoroalkanesulfonic acid anions and pentafluorobenzenesulfonic acid anions. Also R
Two of ²⁰³ , R ²⁰⁴ and R ²⁰⁵ and Ar ¹ and Ar
² may be bonded via each single bond or a substituent. Specific examples include the following compounds, but are not limited thereto.

[0075]

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[0076]

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[0077]

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[0078]

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[0079]

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[0080]

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[0081]

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[0082]

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The above onium salts represented by the general formulas (PAG3) and (PAG4) are known, for example, JWKnapcz
yk etal, J. Am. Chem. Soc., 91, 145 (1969), ALMaycoke
tal, J. Org.Chem., 35, 2532, (1970), E. Goethas et al, Bu
ll.Soc.Chem.Belg., 73,546, (1964), HM Leicester,
J. Ame. Chem. Soc., 51, 3587 (1929), JVCrivello etal,
J. Polym. Chem. Ed., 18,2677 (1980), U.S. Pat.
It can be synthesized by the methods described in JP-A Nos. 8 and 4,247,473 and JP-A-53-101,331. (3) Disulfone derivatives represented by the following general formula (PAG5) or iminosulfonate derivatives represented by the following general formula (PAG6).

[0084]

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

[0086]

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[0087]

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[0088]

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[0089]

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[0090]

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The positive photoresist composition is suitably used for the purpose of improving the alkali solubility of the system and for adjusting the glass transition temperature of the system to prevent the film from becoming brittle and from deteriorating the heat resistance. An alkali-soluble low molecular weight compound may be added. Examples of the alkali-soluble low molecular weight compound include a dialkyl sulfonamide compound, a dialkyl sulfonyl imide (—SO ₂ —NH—CO—) compound, and a dialkyl disulfonyl imide (—SO ₂ —NH
Compounds containing an acidic group in the molecule, such as —SO ₂ —) compounds, may be mentioned. The content of the alkali-soluble low molecular compound is 4 to the binder resin.
The content is preferably 0% by weight or less, more preferably 30% by weight or less, and further preferably 25% by weight or less.

The composition according to the present invention may be used after being dissolved in a specific solvent. As such a solvent, any solvent may be used as long as the solid components are sufficiently dissolved and the solution is an organic solvent capable of forming a uniform coating film by a method such as a spin coating method. In addition, 2
More than one kind may be mixed and used. Specifically, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, tert-butyl alcohol, methyl cellosolve acetate, ethyl cellosolve acetate,
Propylene glycol monoethyl ether acetate,
Methyl lactate, ethyl lactate, 2-methoxybutyl acetate, 2-ethoxyethyl acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, N-methyl-2-pyrrolidinone, cyclohexanone, Cyclopentanone, cyclohexanol, methyl ethyl ketone, 1,4-dioxane,
Ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, 2-
Examples include heptanone, but are not limited thereto.

The positive photoresist composition of the present invention may further contain other components such as a surfactant, a dye, a stabilizer, a coating improver, and a dye, if necessary. Such a positive photoresist composition of the present invention is applied on a substrate to form a thin film. The thickness of this coating film is preferably from 0.4 to 1.5 μm. As the exposure means, A
Preferably, the exposure wavelength is in the range of 170 to 220 nm, such as rF excimer laser stepper exposure,
Particularly preferred is an ArF excimer laser stepper.

[0094]

EXAMPLES The present invention will be described below in more detail with reference to Examples, but it should not be construed that the present invention is limited thereto. Synthesis Example (1) Synthesis of Monomer [IA-1] 1-methoxy-2-methyl-2-propanol was synthesized from 1-chloro-2-methyl-2-propanol and sodium methoxide. Next, 72 g of acrylic acid was dissolved in 500 mL of dichloromethane, and 10 g of 4-dimethylaminopyridine was added. Further, 90 g of 1-methoxy-2-methyl-2-propanol was gently added. This was cooled in an ice bath, and dicyclohexylcarbodiimide 25 was further added.
g was added slowly. After stirring for 30 minutes as it was, the ice bath was removed, the temperature was naturally raised to room temperature, and the mixture was stirred at room temperature for 3 hours. After completion of the reaction, the precipitated powder was separated by filtration, and the obtained filtrate was extracted with 10% aqueous hydrochloric acid, washed with aqueous sodium bicarbonate, washed with saturated saline, and the obtained oil layer was concentrated. This was purified using silica gel column chromatography to obtain 125 g of the desired monomer [IA-1].

Synthesis Example (2) Synthesis of Monomer [IA-7] Monomer [I-A-7] was prepared in the same manner as in Synthesis Example (1) except that sodium methyl methoxide was used instead of sodium methoxide. A-7] was synthesized.

Synthesis Example (3) Synthesis of Monomer [IC-1] The same procedure as Synthesis Example (1) was repeated except that the following carboxylic acid monomer was used instead of acrylic acid. -1]
Was synthesized.

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Synthesis Example (4) Synthesis of Monomer [ID-1] Toa Gosei Aronix M-560 was used instead of acrylic acid.
0 in the same manner as in Synthesis Example (1) except that monomer [I
-D-1].

Synthesis Example (5) Synthesis of Monomer [IF-2] Terminal carboxylic acid synthesized by reacting 3-hydroxypropionic acid with Karenz MOI manufactured by Showa Denko instead of acrylic acid in Synthesis Example (1) A monomer [IF-2] was synthesized in the same manner except that methacrylate was used.

Synthesis Example (6) Synthesis of Resin A Tricyclodecanyl methacrylate 22.0 g Monomer [IA-1] 12.7 g Acrylic acid 1.4 g After dissolving 55 g of THF, nitrogen was added for 30 minutes. Blow in the reaction solution
Heated to 5 ° C. As a polymerization initiator, 100 mg of V-65 (manufactured by Wako Pure Chemical Industries, Ltd.) was added in five divided portions every hour.
After adding the final initiator, the mixture was heated and stirred for 4 hours. After the completion of heating, the reaction solution is returned to room temperature, and THF 100 g
Was added, and the reaction solution was diluted and reprecipitated in a mixed solvent of 2 L of distilled water / 2 L of methanol to recover the target resin A as a white powder. GPC analysis of the obtained copolymer showed that the weight average molecular weight was 32,000 in terms of standard polystyrene.

Synthesis Example (7) Synthesis of Resin B Tricyclodecanyl methacrylate 22.0 g Monomer [IA-9] 13.9 g Acrylic acid 1.4 g After dissolving 57 g of THF, nitrogen was added for 30 minutes. Blow in the reaction solution
Heated to 5 ° C. As a polymerization initiator, 100 mg of V-65 (manufactured by Wako Pure Chemical Industries, Ltd.) was added in five divided portions every hour.
After adding the final initiator, the mixture was heated and stirred for 4 hours. After the completion of heating, the reaction solution is returned to room temperature, and THF 100 g
Was added and the reaction solution was diluted and reprecipitated in a mixed solvent of 2 L of distilled water / 2 L of methanol to recover the target resin B as a white powder. GPC analysis of the obtained copolymer showed that the weight average molecular weight was 33,000 in terms of standard polystyrene.

Synthesis Example (8) Synthesis of Resin C Tricyclodecanyl methacrylate 22.0 g Monomer [IC-1] 24.2 g Acrylic acid 1.4 g After dissolving 70 g of THF, nitrogen was added for 30 minutes. Blow in the reaction solution
Heated to 5 ° C. As a polymerization initiator, 100 mg of V-65 (manufactured by Wako Pure Chemical Industries, Ltd.) was added in five divided portions every hour.
After adding the final initiator, the mixture was heated and stirred for 4 hours. After the completion of heating, the reaction solution is returned to room temperature, and THF 150 g
Was added and the reaction solution was diluted and reprecipitated in a mixed solvent of 3 L of distilled water / 2 L of methanol to recover the target resin C as a white powder. GPC analysis of the obtained copolymer showed that the weight average molecular weight was 35,000 in terms of standard polystyrene.

Synthesis Example (9) Synthesis of Resin D Tricyclodecanyl methacrylate 22.0 g Monomer [ID-1] 20.7 g Acrylic acid 1.4 g After dissolving 66 g of THF, nitrogen was added for 30 minutes. Blow in the reaction solution
Heated to 5 ° C. As a polymerization initiator, 100 mg of V-65 (manufactured by Wako Pure Chemical Industries, Ltd.) was added in five divided portions every hour.
After adding the final initiator, the mixture was heated and stirred for 4 hours. After the completion of heating, the reaction solution is returned to room temperature, and THF 150 g
Was added and the reaction solution was diluted and reprecipitated in a mixed solvent of 3 L of distilled water / 2 L of methanol to recover the target resin D as a white powder. GPC analysis of the obtained copolymer showed that the weight average molecular weight was 34,500 in terms of standard polystyrene.

Synthesis Example (10) Synthesis of Resin E Tricyclodecanyl methacrylate 22.0 g Monomer [IF-2] 26.5 g Acrylic acid 1.4 g After dissolving 80 g of THF, nitrogen was added for 30 minutes. Blow in the reaction solution
Heated to 5 ° C. As a polymerization initiator, 125 mg of V-65 (manufactured by Wako Pure Chemical Industries, Ltd.) was added in five divided portions every one hour.
After adding the final initiator, the mixture was heated and stirred for 4 hours. After the completion of heating, the reaction solution is returned to room temperature, and THF 200 g
Was added, and the reaction solution was diluted and reprecipitated in a mixed solvent of 3 L of distilled water / 3 L of methanol to recover the target resin E as a white powder. GPC analysis of the obtained copolymer showed that the weight average molecular weight was 32,500 in terms of standard polystyrene.

Synthesis Example (11) Synthesis of Comparative Resin F Tricyclodecanyl methacrylate 22.0 g t-butyl acrylate 10.3 g Acrylic acid 1.4 g After dissolving 50 g of THF, nitrogen was blown in for 30 minutes and the reaction solution was dissolved. 6
Heated to 5 ° C. As a polymerization initiator, 100 mg of V-65 (manufactured by Wako Pure Chemical Industries, Ltd.) was added in five divided portions every hour.
After adding the final initiator, the mixture was heated and stirred for 4 hours. After the completion of heating, the reaction solution is returned to room temperature, and THF 100 g
Was added and the reaction solution was diluted and reprecipitated in a mixed solvent of 2 L of distilled water / 2 L of methanol to recover the target resin F as a white powder. GPC analysis of the obtained copolymer showed that the weight average molecular weight was 31,500 in terms of standard polystyrene.

Synthesis Example (12) Synthesis of Comparative Resin G Tricyclodecanyl methacrylate 22.0 g The following monomer a 15.4 g Acrylic acid 1.4 g THF 58 g was dissolved, and then nitrogen was blown in for 30 minutes to react. 6 liquid
Heated to 5 ° C. As a polymerization initiator, 100 mg of V-65 (manufactured by Wako Pure Chemical Industries, Ltd.) was added in five divided portions every hour.
After adding the final initiator, the mixture was heated and stirred for 4 hours. After the completion of heating, the reaction solution is returned to room temperature, and THF 100 g
Was added, and the reaction solution was diluted and reprecipitated in a mixed solvent of 2 L of distilled water / 2 L of methanol to recover the target resin G as a white powder. GPC analysis of the obtained copolymer showed that the weight average molecular weight was 32,300 in terms of standard polystyrene. Monomer a

[0106]

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Synthesis Example (13) Synthesis of Comparative Resin H Tricyclodecanyl methacrylate 22.0 g The following monomer b 11.2 g Acrylic acid 1.4 g THF 58 g was dissolved, and then nitrogen was blown in for 30 minutes to react. 6 liquid
Heated to 5 ° C. As a polymerization initiator, 100 mg of V-65 (manufactured by Wako Pure Chemical Industries, Ltd.) was added in five divided portions every hour.
After adding the final initiator, the mixture was heated and stirred for 4 hours. After the completion of heating, the reaction solution is returned to room temperature, and THF 100 g
Was added and the reaction solution was diluted and reprecipitated in a mixed solvent of 2 L of distilled water / 2 L of methanol to recover the target resin H as a white powder. GPC analysis of the obtained copolymer showed that the weight average molecular weight was 31,000 in terms of standard polystyrene. Monomer b

[0108]

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Synthesis Example (14) Synthesis of Comparative Resin I Tricyclodecanyl methacrylate 22.0 g Monomer c 15.9 g Acrylic acid 1.4 g THF 60 g was dissolved, and then nitrogen was blown in for 30 minutes to react. 6 liquid
Heated to 5 ° C. As a polymerization initiator, 100 mg of V-65 (manufactured by Wako Pure Chemical Industries, Ltd.) was added in five divided portions every hour.
After adding the final initiator, the mixture was heated and stirred for 4 hours. After the completion of heating, the reaction solution is returned to room temperature, and THF 100 g
Was added and the reaction solution was diluted and reprecipitated in a mixed solvent of 2 L of distilled water / 2 L of methanol to recover the target resin I as a white powder. GPC analysis of the obtained copolymer showed that the weight average molecular weight was 32,500 in terms of standard polystyrene. Monomer c

[0110]

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Synthesis Example (15) Synthesis of Photoacid Generator (1) 8 g of sodium hydroxide and 14 g of hydroxyamine hydrochloride
Was dissolved in 200 ml of distilled water, 25 g of dimethylmaleic anhydride was added, and the mixture was stirred at room temperature for 5 hours.
Subsequently, the mixture was heated and stirred at 100 ° C. for 3 hours. After completion of the reaction, aqueous hydrochloric acid was added to the reaction solution, which was further saturated with sodium chloride, and then extracted with ethyl acetate. The operation of concentrating the extracted ethyl acetate solution to 1/3, adding toluene and concentrating again was repeated, and 15 g of N-hydroxymaleimide was isolated.

4.2 g of the N-hydroxymaleimide compound thus synthesized was dissolved in dichloromethane, and trifluoromethanesulfonic anhydride was added while cooling with ice.
5 g was added dropwise over 1 hour. Further, 2.8 g of pyridine
Was added dropwise over 2 hours, the ice bath was removed, the temperature was raised to room temperature, and the mixture was stirred for 10 hours. After completion of the reaction, the reaction solution was washed with distilled water or the like, concentrated, crystallized in hexane, and the hexane layer was further concentrated to obtain 10 g of the desired product. The following structure was confirmed by ¹³ CNMR.

[0113]

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Examples and Comparative Examples 1.2 g of each of the resins A to I synthesized in the above synthesis examples, and 0.2 g of the photoacid generator (1).
25 g was dissolved in 2-heptanone at a solid content of 14% by weight, and then filtered through a 0.1 μm microfilter to prepare a positive photoresist composition solution. The formulation is shown in Table 1 below.

(Evaluation Test) The obtained positive photoresist composition solution was applied on a silicon wafer by using a spin coater, dried at 120 ° C. for 90 seconds, and dried at about 0.5 μm.
Was prepared and exposed to an ArF excimer laser (193 nm). A heat treatment after exposure was performed at 110 ° C. for 90 seconds, developed with a 2.38% aqueous solution of tetramethylammonium hydroxide, and rinsed with distilled water to obtain a resist pattern profile.

[Relative sensitivity] : The exposure amount capable of reproducing a 0.5 μm pattern was defined as the sensitivity, the resist sensitivity of Example 1 was defined as 1, and the relative sensitivity of the resists other than Example 1 was obtained by the following equation. That is, sensitivity other than Example 1 / sensitivity of Example 1

[Pattern Profile] : The resist pattern profile obtained above was observed with a scanning electron microscope, and a rectangular pattern was evaluated as 、 and a T-top pattern was evaluated as ×.

[Adhesion] (Minimum line width of remaining fine line) : The resist pattern profile obtained above was observed with a scanning electron microscope, and evaluated based on the line width of the remaining fine line. That is, a pattern having a higher adhesiveness has a pattern with a finer line width remaining, while a pattern having a lower adhesiveness cannot be adhered to a substrate interface with a smaller line width, and the pattern is peeled off. Table 1 shows the results.

[0119]

[Table 1]

[Transmission Density] The same composition as the positive photoresist composition solution applied on the silicon wafer in the above test was applied on a silica plate having no light absorption in the far ultraviolet region using a spin coater. A sample for concentration measurement was prepared. Using a spectrodensitometer, measure the spectral absorption in the far ultraviolet to determine the transmission density at 193 nm,
This was divided by the coating thickness of the sample to determine the transmission density per micron of the coating thickness of the sample. Table 2 shows the results.

[0121]

[Table 2]

In Table 1, each of the comparative examples has problems in terms of relative sensitivity, pattern profile, and adhesion. On the other hand, Examples 1 to 6 relating to the positive photoresist composition of the present invention are all at a satisfactory level. That is, it is suitable for lithography using far ultraviolet rays such as ArF excimer laser exposure.

On the other hand, in Table 2, the samples A to E of the present invention
The transmission density per micron thickness at 193 nm was 0.4 or less in each case, indicating that the light absorption for the exposure for patterning was sufficiently lower than the comparative sample. This means that the light is irradiated to the composition layer side of the substrate without significant attenuation, and this is reflected in the good pattern profile and high relative sensitivity shown in Table 1. Note that, despite the fact that Comparative Examples 1 and 4 use a resin having a low transmission density, the photoresist characteristics in Table 1 show that:
Inferior to the sample of the present invention means that a low transmission density is a necessary condition to have excellent far ultraviolet photoresist properties, but is not a sufficient condition.

[0124]

As described above, the present invention has a
It is possible to provide a positive photoresist composition which is sufficiently suitable for light in a wavelength region of 0 nm to 220 nm, has high sensitivity, excellent adhesion, and can obtain a good resist pattern profile.

Claims (5)

[Claims] 1. A positive photoresist composition containing a resin which decomposes under the action of an acid to increase its solubility in alkali and a compound which generates an acid upon irradiation with actinic rays or radiation. A positive photoresist composition for deep ultraviolet exposure, wherein the resin having increased solubility in alkali is a polymer containing a monomer represented by the following general formula [I] as one of the repeating structural units. Stuff. Embedded image (Wherein, R ₁ represents a hydrogen atom or a methyl group, and R _{2 to} R
₄ may be the same or different and represents a hydrogen atom or an alkyl group. R ₅ and R ₆ may be the same or different and each represents a hydrogen atom, an alkyl group or an XR ₇ group, wherein R ₇ is a hydrogen atom or an alkyl group, and X is an oxygen atom or a sulfur atom. A is a single bond, an alkylene group, a substituted alkylene group,
It represents one group selected from the group consisting of an ether group, an ester group, a thioether group, a carbonyl group, an amide group, a sulfonamide group, a urethane group, and a urea group, or a group obtained by combining two or more thereof. m represents 1, 2 or 3, n represents 0, 1 or 2, and the sum of m and n represents 3. ) 2. A resin which decomposes under the action of an acid to increase its solubility in alkali is a repeating structure of a monomer represented by the general formula [I] and a monomer having an aliphatic cyclic hydrocarbon moiety in the molecule. The positive photoresist composition for deep ultraviolet exposure according to claim 1, which is a copolymer having units. 3. The positive photoresist composition for deep ultraviolet exposure according to claim 1, wherein the wavelength of the actinic ray or radiation to be exposed is 170 to 220 nm. 4. The distant resin according to claim 1, wherein the resin further comprises a repeating structural unit having a group which is further decomposed by the action of an acid to increase the solubility in an alkali developing solution. A positive photoresist composition for UV exposure. 5. The method according to claim 1, wherein an optical density per 1.0 micron of the thickness of the coating is 1.0 or less for an actinic ray having a wavelength of 193 nm. A positive photoresist composition for deep ultraviolet exposure.