JPH11109630A - Positive photoresist composition for exposure with far ultraviolet ray - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photoresist compsn. having low absorbance to an ArF excimer laser light source and excellent in adhesion to a substrate, excellent in standard developing and a pattern profile by combining a resin contg. a specified acetal structure as an acid decomposable group with a photo-acid generating agent. SOLUTION: A photoresist compsn. contains a resin which is decomposed by the action of an acid and increases its alkali solubility and a compd. which generates the acid by irradiating active light beams or radiation. The resin contains a monomer as repeating units in which a partial structure represented by formula is linked directly to a polymerizable carbon-carbon double bond or through a divalent org. combining group. In the formula, R1 is an H atom or an alkyl group, R2 is an alkyl group substd. so that an inorg. numerical value in an org. conceptional diagram becomes >=100 and this substituent R2 is preferably 1-12C an alkyl group.

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 The degree of integration of integrated circuits is increasing, and in the manufacture of semiconductor substrates such as VLSI, processing of ultrafine patterns having a line width of less than half a micron is required. Have been. In order to meet this need, the wavelength of an exposure apparatus used for photolithography is becoming shorter and shorter, and now excimer laser light (XeCl, KrF, ArF, etc.) having a short wavelength even in far ultraviolet rays is used.
The use of is being considered. In lithography pattern formation in this wavelength region,
Since novolak and naphthoquinonediazide have a strong absorption in the deep ultraviolet region, light hardly reaches the bottom of the resist, and only a low-sensitivity, tapered pattern can be obtained. It is enough.

One of the means for solving this problem is a chemically amplified resist composition described in US Pat. No. 4,491,628, European Patent No. 249,139 and the like. 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 the developer. 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 a combination of a photoacid generator and a resin for the above-described two-component or 2.5-component system whose solubility is changed by an acid, a combination of an acetal or an O, N-acetal compound ( JP-A-48-89003), a combination with an orthoester or an amide acetal compound (JP-A-51-120714), a combination with a polymer having an acetal or ketal group in the main chain (JP-A-53-1)
No. 33429), a combination with an enol ether compound (JP-A-55-12995), 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), and a combination with a silyl ester compound (JP-A-60-10247).
Tertiary or secondary carbon (for example, t-butyl, 2-cyclohexenyl) or a combination thereof with a carbonate compound (JP-A-63-250542, Polym. Eng. Sci., 2).
Volume 3, page 1012 (1983); ACS.Sym. 242, page 11 (198
4); Semiconductor World 1987, November, p. 91; Mac
romolecules, 21, 21475 (1988); SPIE, 920, 42
(1988)) and a combination with a silyl ether compound (JP-A-60-37549, JP-A-60-12144).
No. 6). These have high photosensitivity because the quantum yield exceeds 1 in principle.

As described above, a chemically amplified resist is suitable for a photoresist for irradiation with ultraviolet rays or salt ultraviolet rays.
Among them, it is necessary to further cope with required characteristics in use. For example, when using KrF excimer laser light of 248 nm, 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 low light absorption is proposed. Have been. JP-A-2-141636, JP-A-2-1984
7, JP-A-4-219775, JP-A-5-281745
For example, Japanese Unexamined Patent Publication (Kokai) No. H10 is an example. In addition, a similar composition having a t-butoxycarbonyloxy group or a p-tetrahydropyranyloxy group as an acid-decomposable group is disclosed in JP-A-2-20997.
7, JP-A-3-206458, JP-A-2-19847, etc.). These are suitable when using a KrF excimer laser at 248 nm, but have low sensitivity when using an ArF excimer laser as a light source, because the absorbance is still still essentially 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.

[0007] 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.

Further, in Japanese Patent Application Laid-Open No. 7-234511,
There is disclosed a technique for improving adhesion by introducing an alcoholic hydroxyl group such as 2-hydroxyethyl (meth) acrylate or acrylonitrile or a cyano group into a (meth) acrylic resin for an rF light source. Also, Journal of Photopoly
mer Science and Technology, Vol.10, 1997, p545-550
And Journal of Photopolymer Science and Technolog
y, Vol. 9, 1996, p509-522, focuses on lactone structures such as mevalonic lactone for the purpose of improving substrate adhesion. However, in order to impart standard developer suitability (the property of being able to develop to a satisfactory performance with a 2.38% aqueous solution of tetramethylammonium hydroxide, which is a standard developer commonly and widely used internationally), The problem is that an overcoat layer is required, and the substrate adhesion is also insufficient.

Further, Journal of Photopolymer Scienc
e and Technology, Vol. 10, 1997, pp. 561-570, reports an attempt to achieve both dry etching resistance and substrate adhesion by using a monomer with a pendant carboxylic acid group at the side chain alicyclic moiety. However, this partially protected polymer has a problem in suitability for a standard developer, and although a part of the polymer is replaced with a monomer having an alcoholic hydroxyl group in a molecule to provide the suitability for a standard developer, it is still insufficient. . Meanwhile, Journal of Photopolymer Science and Te
chnology, Vol. 10, 1997, p529-534 and Journal of Ph
otopolymer Science and Technology, Vol.10, 1997, p5
In 21-528, an alicyclic moiety is introduced into the polymer main chain for the purpose of imparting dry etching resistance, and an alcoholic hydroxyl group is introduced into the alicyclic moiety from the viewpoint of providing substrate adhesion. However, the substrate adhesion was still insufficient, and the profile still had problems.

As described above, the photoresist composition for an ArF light source has high transparency with respect to active light and high sensitivity. However, its weak points, that is, insufficient substrate adhesion and standard development suitability, are not sufficient. Intensive development efforts have been made to address the accompanying dissatisfaction with the pattern profile. However, a technique for solving all of the weak points of the (meth) acrylic resin for the ArF light source has not yet been found.

[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. It is an object of the present invention to develop a resist composition that satisfies necessary characteristics such as substrate adhesion, standard development suitability, and pattern profile for use of a short wavelength light source. Among them, it is an object of the present invention to develop a photoresist composition which has a low absorbance especially for an ArF excimer laser light source, and has excellent substrate adhesion, standard developability and pattern profile.

[0012]

Means for Solving the Problems The present inventors diligently studied constituent materials of a resist composition in a positive-type chemical amplification system, and found that an acetal structure having a specific structure appropriately imparted hydrophilicity was used as an acid-decomposable group. The inventors have found that the object can be achieved by the combination of the resin and the photoacid generator, and have accomplished the present invention. That is, the above object is achieved by a positive photoresist composition having the following constitution.

1. In a positive photoresist composition for deep-ultraviolet light exposure containing a resin that decomposes by the action of an acid to increase solubility in alkali and a compound that generates an acid by irradiation with actinic rays or radiation, The resin having increased solubility contains, as a repeating unit, a monomer in which a partial structure represented by the following general formula [I] is directly or via a divalent organic linking group to a polymerizable carbon-carbon double bond. A positive photoresist composition for deep ultraviolet exposure.

[0014]

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In the formula, R ₁ represents a hydrogen atom or an alkyl group, and R ₂ represents an inorganic compound having a numerical value of 10
Represents an alkyl group substituted to be 0 or more.

2. The positive photoresist composition for deep ultraviolet exposure according to the above item 1, wherein the substituent R ₂ in the partial structure represented by the general formula [I] is an alkyl group having 1 to 12 carbon atoms. .

3. The partial structure represented by the general formula [I] is
3. The positive photoresist composition for deep UV exposure according to the above item 1 or 2, which is represented by the following general formula [II].

[0018]

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Wherein R ₃ , R ₄ and R ₅ are a hydrogen atom,
Alkyl group, cycloalkyl group, hydroxyalkyl group, alkoxyaskill group, hydroxyalkoxyalkyl group, acylaminoalkyl group, sulfoaminoalkyl group, carboxyl group, carboxyalkyl group, acylamino group, sulfamino group, sulfamoyl group, sulfoaminosulfo Represents an alkyl group, a carbamoyl group, an alkoxy group, an acyl group, a hydroxyl group or a cyano group.

4. Wherein the wavelength of the actinic ray or radiation to be exposed is 170 to 220 nm.
4. The positive photoresist composition for deep ultraviolet exposure according to 3. 5. 5. The positive for ultraviolet ray exposure according to any one of the above items 1 to 4, wherein a transmission optical density per 1 micron of the thickness of the coated article with respect to an actinic ray having a wavelength of 193 nm is 1.0 or less. -Type photoresist composition.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the constitution of the positive photoresist composition of the present invention will be described in detail. First, the partial structure represented by the general formula [I] of the resin of the present invention, which is decomposed by the action of an acid and increases the solubility in an alkaline developer, will be described. In the general formula [I], R
₁ represents a hydrogen atom or an alkyl group, and in the case of an alkyl group, is preferably a straight-chain or branched alkyl having 1 to 12 carbon atoms, and more preferably a straight-chain or branched alkyl having 1 to 4 carbon atoms. Particularly preferred R ₁ is a hydrogen atom or a methyl group. R ₂ represents an alkyl group having an inorganic value of 100 or more in the organic conceptual diagram (that is, an alkyl group having a sum of the inorganic values of each substituent that is substituted on the alkyl group is 100 or more). The organic conceptual diagram is a diagram conceptually displaying the size and balance of the organic and inorganic properties of the substituent by numerically expressing the size of the organic and inorganic properties of the substituent. The first of "Organic Conceptual Map" (Sankyo Shuppansha, first edition published in 1983)
See Chapter (pages 1-31). An inorganic value of 100 or more in the organic conceptual diagram means that the organic compound has relatively high hydrophilicity. In order to improve the substrate adhesion, the present inventor requires that a group that decomposes by the action of an acid and increases solubility in an alkaline developer (hereinafter referred to as an acid-decomposable group) is somewhat hydrophilic. It was found necessary, and as a result of examination, it was found that the value of the inorganicity of R ₂ was 100 or more.

Hydrophilic substituents that can be included in R ₂ include alcoholic hydroxyl groups, lactone rings, COOH
Group, amide group, sulfonamide group, imide group, N-sulfonylamide group, N, N-disulfonylamino group and the like, and one or more of these may be included. When containing a plurality of hydrophilic groups, the substituents are ether groups, chain ester groups, carbonyl groups, sulfonyl groups, sulfonate groups, cyano groups, etc., each of which is combined with a plurality or the above-described hydrophilic groups. I have.

R ₂ is an alkyl group containing the above-mentioned hydrophilic group as a substituent, specifically, an alkyl group having a primary, secondary, or tertiary alcoholic hydroxyl group;
A 5- to 7-membered lactone ring or an alkyl group containing the lactone ring, an alkyl group having a primary, secondary, or tertiary COOH group;
Amide group, sulfonamide group, imide group, N-sulfonylamido group, substituted alkyl group containing N, N-disulfonylamino group, polyethylene glycol group, etc. An alkyl group containing a plurality of ether groups, an ether group,
Alkyl group, ether group, chain ester group having a chain ester group, carbonyl group, sulfonyl group, sulfonate group, cyano group as a substituent and having a primary, secondary, or tertiary alcoholic hydroxyl group , A lactone ring having a 5- to 7-membered ring or an alkyl group containing the same, an ether group, a chain ester group, a carbonyl group, a sulfonyl group having a carbonyl group, a sulfonyl group, a sulfonate group, or a cyano group as a substituent. Group, a sulfonate group or a cyano group as a substituent, and 1
An alkyl group, ether group, chain ester group, carbonyl group, sulfonyl group, sulfonate group, cyano group having a secondary or secondary COOH group as a substituent, and an oxygen atom and an alkylene group Combine
An amide group, a sulfonamide group, an imide group, an N- group sandwiched between linear or branched, cyclic alkyl groups having 1 to 8 carbon atoms;
It is a substituted alkyl group containing a sulfonylamide group and an N, N-disulfonylamino group.

The inventor of the present invention has proposed an R which satisfies all excellent substrate adhesion, standard developer suitability and pattern profile.
As a result of further study of the conditions of ₂ , the inorganic value was 100
In addition to the above, I have learned that an appropriate balance between organic and inorganic properties is also necessary. From these results, the preferred carbon number of R ₂ is 1 to 12. Inorganic value is 10
Preferred R ₂ having 0 or more and 1 to 12 carbon atoms is
An alkyl group represented by the general formula [II].

In the general formula [II], R ₃ , R ₄ and R
₅ is hydrogen atom, methyl group, ethyl group, i-propyl group, n-propyl group, i-butyl group, n-butyl group, t
Alkyl groups such as -butyl group, cyclohexyl group, cycloalkyl group such as cyclopentyl group, ethoxyethyl group, propoxyethyl group, alkoxyalkyl group such as ethoxyethoxyethyl group, hydroxyethyl group, hydroxypropyl group, hydroxybutyl group and the like. Hydroxyalkyl group, hydroxyethoxyethyl group, hydroxyethoxypropyl group, hydroxyalkoxyalkyl group such as hydroxypropoxyethyl group, acetylaminomethyl group, N-methylacetylaminomethyl group, acetylaminoethyl group, propionoylaminomethyl group, Acylaminoalkyl groups such as propionoylaminoethyl group and butyroylaminoethyl group, methylsulfaminoaminoethyl group, methylsulfaminoaminoethyl group, t-butylsulfamino Butyl group, N- methyl sulfonium sulfo aminoalkyl group such as aminoethyl group, a carboxyl group, a carboxymethyl group, a carboxyethyl group,
Carboxyalkyl groups such as 2-carboxypropyl group and 3-carboxypropyl group; acylamino groups such as acetylamino group and propionoylamino group; methylsulfoamino group; ethylsulfoamino group; i-propylsulfoamino group; Sulfoamino groups such as propylsulfoamino group, carbamoyl groups such as methylaminocarbonyl group and butylaminocarbonyl group, N-methylmethylsulfoaminosulfomethyl group, N-methylethylsulfoaminosulfomethyl group, N-methylmethylsulfoaminosulfo group A sulfoaminosulfoalkyl group such as an ethyl group, N
-Methylaminosulfonyl group, N- (n-butyl) aminosulfonyl group, sulfamoyl group such as N, N-dimethylaminosulfonyl group, alkoxy group such as methoxy group and ethoxy group, and acyl group such as acetyl group and propionoyl group. , A hydroxyl group or a cyano group.

Each of these substituents further comprises an alkyl group,
A hydroxyl group, a hydroxyalkyl group, an acyl group, a cyclohexyl group that may be substituted with an alkylsulfo group, or a hydroxy group or a cyclohexyl group that may be substituted with a hydroxyalkyl group, or an alkyl group; Although it may be substituted directly with a 7-membered lactone or via an ether oxygen or a carbonyl group,
The total number of carbon atoms of R ₃ , R ₄ and R ₅ is 12 or less.

The resin of the present invention is characterized in that it contains an acetal-type acid-decomposable group having a substituent having a specific structure represented by R ₂ described above, whereby the pattern profile, substrate adhesion, and standard development A photoresist composition for deep ultraviolet exposure that satisfies the required properties such as suitability can be obtained. Specific examples of substituents of the specific structure represented by the R ₂ are shown below, R ₂ is not limited thereto.

[0028]

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[0029]

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[0030]

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[0031]

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In the resin of the present invention, which is decomposed by the action of an acid to increase the solubility in an alkaline developer, the partial structure represented by the above general formula [I] or [II] has the following structural formula As shown in (a), it is directly bonded to the main chain via a linking group A as shown in the following structural formula (b) to form a repeating structural unit.

[0033]

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In the above structural formula, A represents a single bond, an alkylene group, a substituted alkylene group, a cyclic alkylene group, an ether group, a thioether group, a carbonyl group, an ester group,
A divalent group selected from the group consisting of an amide group, a sulfonamide group, a urethane group, and a urea group;
Represents a divalent group obtained by combining two or more. Also, R ₁ , R
₂ has the same meaning as in general formula (I).

More specifically, the alkylene group and the substituted alkylene group include the following groups. -[C (R _e ) (R _f )] _q-wherein R _e and R _{f each} represent a hydrogen atom, an alkyl group, a substituted alkyl group, a halogen atom, a hydroxyl group, or an alkoxy group. 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, and more preferably selected from the group consisting of a methyl group, an ethyl group, a propyl group and an isopropyl group. Represents a substituent. 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. q represents an integer of 1 to 10. Further, the cyclic alkylene group is a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, a 2-methyl-2-adamantyl group, a norbornyl group, a boronyl group, an isobornyl group, a tricyclodecanyl group, a tetracyclododecanyl group, It is a divalent group having a second linking bond at an arbitrary site of each monocyclic or polycyclic group such as a dicyclopentenyl group, a nobornane epoxy group, a menthyl group, an isomenthyl group, and a neomenthyl group.

The above resin in the positive photoresist composition of the present invention comprises a repeating structural unit having a partial structure represented by the above general formula [I] and a repeating structural unit having an aliphatic cyclic hydrocarbon moiety in the molecule. Can be included. 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 [A] or [B].

[0037]

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[0038]

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R ₄₁ in the general formula [A] is a monovalent aliphatic cyclic hydrocarbon group. Specifically, an adamantyl group, 2-
Methyl-2-adamantyl, norbornyl, boronyl, isobornyl, tricyclodecanyl, tetracyclododecanyl, dicyclopentenyl, nobornane epoxy, menthyl, isomenthyl, neomenthyl, etc. Can be. In the general formula [B], R ₄₂
Is a linking group having a divalent aliphatic cyclic hydrocarbon site. G is -COOH, -OH, -COOR ₄₃ or -O
Representing the R _43. R ₄₃ represents a tertiary alkyl group, tetrahydropyranyl group, tetrahydrofuranyl group, a -CH ₂ OR ₄₄ or -CH (CH ₃₎ OR _44. R ₄₄ represents an alkyl group. R ₄₀ represents a hydrogen atom or a methyl group. Examples of the aliphatic cyclic hydrocarbon moiety contained in the linking group R _42, for example, or a divalent tetracyclododecanyl group include the following structure.

[0040]

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Further, the linking group in R ₄₂ 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.

-COOR₄₃Group or -OR₄₃In the base
R₄₃Is 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.

The content of the repeating structural unit having an aliphatic cyclic hydrocarbon moiety in the resin in the resin is preferably 70 mol% or less, more preferably 50 mol% or less, and still more preferably all the repeating units. 30 mol% or less. Further, the content of the acid-decomposable group of the general formula [I] in the resin is preferably at least 30 mol%, more preferably at least 40 mol%, even more preferably 5 mol% based on all repeating units.
0 mol% or more. The constitution of the resin of the present invention is sufficiently high in the transmittance for far ultraviolet light, the effect of light reaches the bottom of the resist composition, and a good resist pattern can be formed. The transmission density is preferably 1.0 or less per 1 micron thickness of the resist film.

The resin according to the present invention is further decomposed 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. (Also referred to as an acid-decomposable group). As such an acid-decomposable group, the above-mentioned —COOR ₄₃ , —OR ₄₃ , 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, 3-oxocyclohexyl acrylate, 3-
Oxocyclohexyl methacrylate, 2-oxocyclohexyl acrylate, 2-oxocyclohexyl methacrylate and the like can be mentioned.

In the above resin, the content of the repeating structural unit based on such a monomer having an acid-decomposable group is preferably not more than 50 mol%, more preferably not more than 50 mol%, based on all repeating units. 30 mol% or less. If the value exceeds 50 mol%, the dry etching resistance tends to deteriorate, and the effect of the present invention is not sufficiently exhibited, which 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 acrylic esters, methacrylic esters,
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, acrylates 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, for example, alkyl (preferably having 1 to 10 carbon atoms in the alkyl group) methacrylate (for example, 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, (alkyl having 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 (alkyl having 1 to 10 carbon atoms, for example, methyl, ethyl, t-butyl, ethylhexyl, hydroxyethyl, cyclohexyl) 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 fumaric acid (eg, dibutyl fumarate, etc.) or monoalkyl esters;
Acrylic acid, methacrylic acid, crotonic acid, itaconic acid,
Examples include maleic anhydride, maleimide, acrylonitrile, methacrylonitrile, maleilenitrile, and the like.

In addition, any addition-polymerizable unsaturated compound copolymerizable with the repeating unit having the partial structure represented by the general formula [I] may be added as a monomer component for copolymerization. The content of the repeating unit in the resin by the monomer to be further added is 9 to the total number of moles of the repeating structural unit containing the partial structure represented by the general formula [I].
It is preferably at most 9 mol%, more preferably at most 90 mol%, further preferably at most 80 mol%. 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.

The resin containing a repeating structural unit having a partial structure represented by the above-mentioned general formula [I] can be obtained by radical polymerization according to a conventional method using a radical initiator such as an azo compound with respect to a polymerization reaction. The acetal esterification reaction can be obtained by reacting the corresponding carboxylic acid compound with an alkoxymethyl halide under basic conditions, or by reacting the corresponding carboxylic acid compound with vinyl ethers under acidic conditions.

As described above, the resin according to the present invention has improved adhesion to the substrate, and has a strong light-absorbing group in the far ultraviolet region such as ArF light in both the main chain and the side chain. Therefore, the irradiation light sufficiently spreads also near the substrate surface of the coating film, which results in high sensitivity and an excellent 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 satisfies such requirements. Meets

The positive photoresist composition of the present invention comprises
It mainly contains the resin as described above 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), etc., and sulfonium salts represented by the following general formula [III], disulfones represented by the following general formula [IV], and the following general formula The compound represented by [V] can be mentioned.

[0063]

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Here, R _{100 to} R ₁₀₃ each represent an alkyl group or a cyclic alkyl group. These may be the same or different from each other. Further, N- represented by the following general formula [VI]
Hydroxymaleimide sulphonates are also suitable.

[0065]

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Here, R ₁₀₄ and R ₁₀₅ 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 ₁₀₄ and R ₁₀₅ may be bonded via an alkylene group to form a ring. R
₁₀₆ 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.

R ₁₀₄ and R ₁₀₅ in the above general formula [VI]
Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group. Can be. 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
Examples of a case where ₁₀₄ and R ₁₀₅ form 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 ₁₀₆ , a straight-chain carbon group having 1 to 2 carbon atoms, such as a methyl group, an ethyl group and a propyl group.
0 alkyl groups, isopropyl groups, isobutyl groups,
Examples include a branched alkyl group having 1 to 20 carbon atoms such as a 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 together 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, etc.

JVCrivello etal, 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, JP-A-2-150,848, JP-A-2-296,514
Salt, JVCrivello etal, Poly
mer J. 17, 73 (1985), JVCrivello et al. J. Org. Chem.,
43,3055 (1978), WRWatt et al, J. Polymer Sci., Polym
er Chem. Ed., 22, 1789 (1984), JVCrivello etal, Poly
mer Bull., 14,279 (1985), JVCrivello etal, Macromor
ecules, 14 (5), 1141 (1981), JVCrivello et al, J. Poly
merSci., Polymer Chem. Ed., 17, 2877 (1979), European Patent No.
370,693, 3,902,114, 233,567, 297,44
Nos. 3,297,442; U.S. Pat.Nos. 4,933,377, 161,
811, 410,201, 339,049, 4,760,013
No. 4,734,444, No. 2,833,827, Dokoku Patent No. 2,90
Nos. 4,626, 3,604,580, 3,604,581, etc., sulfonium salts, JVCrivello et al., Macromorecules, 1
0 (6), 1307 (1977), JVCrivello etal, J.PolymerSci.,
Selenonium salts described in Polymer Chem.Ed., 17, 1047 (1979), etc., CSWen et al., Teh, Proc. Conf. Rad. Curing ASI
A, p478 Tokyo, Oct (1988) etc. onium salts such as arsonium salts,

US Pat. No. 3,905,815, JP-B-46-4605
No., JP-A-48-36281, JP-A-55-32070, JP-A-60-2
39736, JP-A-61-169835, JP-A-61-169837,
JP-A-62-58241, JP-A-62-212401, JP-A-63-702
No. 43, organic halogen compounds described in JP-A-63-298339, etc., K. Meier et al., J. Rad.Curing, 13 (4), 26 (1986), TP
Gill et al., Inorg.Chem., 19,3007 (1980), D. Astruc, Ac
c. Chem. Res., 19 (12), 377 (1896), organometallics / organic halides described in JP-A-2-14145 and the like,

S. Hayase et al., J. Polymer Sci., 25, 753 (1
987), E. Reichmanis et al., J. Pholimer Sci., Polymer Ch.
em.Ed., 23,1 (1985), QQZhu et al., J.Photochem., 36,8
5,39,317 (1987), B. Amit etal, Tetrahedron Lett., (24)
2205 (1973), DHR Barton et al., J. Chem Soc., 3571 (196
5), PMCollins et al., J. Chem.SoC., Perkin I, 1695 (197
5), M. Rudinstein et al., Tetrahedron Lett., (17), 1445
(1975), JWWalker etal J. Am. Chem. Soc., 110, 7170 (198
8), SCBusman et al., J. Imaging Technol., 11 (4), 191 (1
985), HM Houlihan et al, Macormolecules, 21, 2001 (198
8), PMCollins et al., J. Chem. Soc., Chem. Commun., 532 (1
972), S. Hayase et al, Macromolecules, 18, 1799 (1985),
E. Reichmanis etal, J. Electrochem. Soc., Solid State S
ci.Technol., 130 (6), FMHoulihan et al, Macromolcule
s, 21, 2001 (1988), European Patent Nos. 0290,750 and 046,083
Nos. 156,535, 271,851, 0,388,343, U.S. Pat.Nos. 3,901,710 and 4,181,531, JP-A-60-198
No. 538, JP-A-53-133022 and the like, a photoacid generator having an o-nitrobenzyl-type protecting group,

M. TUNOOKA etal, Polymer Preprints Japa
n, 35 (8), G.Berner et al., J.Rad.Curing, 13 (4), WJMijs
etal, Coating Technol., 55 (697), 45 (1983), Akzo, HA
dachi etal, Polymer Preprints, Japan, 37 (3), European Patent Nos. 0199,672, 84515, 199,672, 044,115
No. 0101122, U.S. Pat.Nos. 618,564, 4,371,60
No. 5, 4,431,774, JP-A-64-18143, JP-A 2-24
Compounds that generate sulfonic acid upon photolysis, such as iminosulfonates described in JP-A-5756 and Japanese Patent Application No. 3-140109, and disulfone compounds described in JP-A-61-166544. Can be.

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 compounds which can be used together and which decompose upon irradiation with actinic rays or radiation to generate an acid, 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).

[0079]

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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.

[0081]

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[0082]

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[0083]

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

[0085]

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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. .

[0088] 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.

[0089]

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[0090]

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[0091]

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[0092]

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[0093]

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[0094]

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[0095]

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[0096]

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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).

[0098]

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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.

[0100]

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[0101]

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[0102]

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[0103]

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[0104]

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The positive photoresist composition is suitable for the purpose of improving the alkali solubility of the system, adjusting the glass transition temperature of the system, and preventing 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.

[0108]

(Synthesis example)

(1) Synthesis of Monomer a After dicyclopentadiene was thermally decomposed at 170 to 180 ° C., cyclopentadiene was distilled out. 21 g of the obtained cyclopentadiene and t-butyl acrylate 4
1 g was mixed and heated and stirred at 40 ° C. for 12 hours. The obtained reaction mixture was distilled under reduced pressure to synthesize 50 g of the desired t-butoxycarbonylnorbornene. Next, after reacting t-butoxycarbonylnorbornene and methacrylic acid by the method described in JP-A-8-333304,
The t-butyl ester moiety was acid-hydrolyzed to obtain the desired monomer a.

(2) Synthesis of Monomer b Monomer a synthesized in the above synthesis example (1) and excess 2-hydroxyethyl vinyl ether were dissolved in methyl isobutyl ketone, and a small amount of 2-ethylhexyl phosphoric acid was added. The mixture was stirred for 24 hours under a nitrogen atmosphere. After completion of the reaction, the mixture was washed with aqueous sodium bicarbonate, excess 2-hydroxyethyl vinyl ether was distilled off under reduced pressure, dissolved again in ethyl acetate, and further dissolved in 5% NaO 3.
Washed with an aqueous H solution and washed with saturated brine until the water became neutral, and the resulting oil layer was concentrated to obtain the target monomer b. The following monomers c to i were synthesized in the same manner.

[0110]

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(3) Synthesis of Monomer j Monomer a synthesized in the above synthesis example (1) was previously reacted with triethylamine to form an ammonium salt, which was dissolved in dimethylformamide to give chloromethyl-2 -Hydroxyethyl ether is slowly added dropwise,
Stirred at room temperature for hours. The obtained reaction solution was concentrated, and dimethylformamide was distilled off. It was dissolved again in ethyl acetate, washed with aqueous sodium bicarbonate, concentrated again, and purified by silica gel column chromatography to synthesize the desired monomer j.

The following monomers k to r were synthesized in the same manner. The sum of the inorganic values in the organic conceptual diagrams of the monomers b to r according to the present invention and the monomers s to u for comparison is as follows:
Each is as follows. b, 100, c; 100, d; 100, e; 140, f; 200, g; 200, h; 240, i; 175, j; 100, k; 100, l; 100, m; 140, n; 200, o; 200, p; 240, q; 240, r; 175, s; 85, t; 20, u;

[0113]

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(4) Synthesis of Resin B 10 g of a mixture of monomers a and b in a 4/6 molar ratio was dissolved in 30 g of tetrahydrofuran, and the mixture was heated to 60 ° C. under a nitrogen atmosphere. 200 V-65
mg was added in five portions every 1 hour, and the mixture was further stirred for 3 hours. The obtained reaction mixture is mixed with tetrahydrofuran 1
After diluting with 00 g, crystallization in 1.5 L of distilled water, and the precipitated white powder were separated by filtration to collect the target resin B. GPC measurement of the obtained resin B showed that the weight average molecular weight in terms of standard polystyrene was 12,100. Thereafter, resins C to R, which are copolymers of the monomer a and the monomers cr (the molar ratio thereof is 4/6), were synthesized in the same manner.

[0115]

[Table 1]

(5) Synthesis of Comparative Resins S, T and U The same general radicals as in Synthesis Example (4) were obtained by using monomers s, t and u represented by the following formulas and monomer a as raw materials. Comparative resins S, T and U were synthesized by a polymerization method. The obtained resin S,
When GPC measurement of T and U was performed, the weight average molecular weights in terms of standard polystyrene were 11400 and 10400, respectively.
200, 9900.

[0117]

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(6) Synthesis of Comparative Resins V and W Journal of Photopolymer Science and Technology, Vo
l.10, 1997, p545-550, the following resin V
nal of photopolymer Science and Technology, Vol.1
A resin W containing an alcohol monomer was synthesized by the method described in J. P. No. 0, 1997, p561-570.

[0119]

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(7) Synthesis of Comparative Resins X and Y Resins described in Examples 10 and 17 of JP-A-7-234511 were synthesized according to the method described in the patent to obtain corresponding resins X and Y.

[Examples / Comparative Examples] (1) Preparation of Test Samples Resins B to R of the present invention synthesized in the above Synthesis Examples and Resins S to Y of Comparative Examples 1.2 g each, and a photoacid generator After dissolving 0.25 g of triphenylsulfonium triflate in 2-heptanone at a solid content of 14% by weight,
The solution was filtered through a 0.1 μm microfilter to prepare a positive photoresist composition solution. The obtained positive photoresist composition solution was applied on a silicon wafer using a spin coater, dried at 120 ° C. for 90 seconds, and dried for about 0.5 hour.
μm positive type photoresist film is formed, and ArF
It was exposed with an excimer laser (193 nm). A heat treatment after exposure was performed at 110 ° C. for 90 seconds, developed with a 2.38% aqueous tetramethylammonium hydroxide solution as a standard developer, and rinsed with distilled water to obtain a resist pattern profile.

(2) Evaluation method [Pattern profile]: The resist pattern profile obtained above was observed with a scanning electron microscope. On the contrary, those showing a T-top shape due to poor developability were evaluated as x.

[Adhesion] (Minimum line width of remaining fine line): A resist pattern profile obtained by exposing at this exposure amount with the exposure amount reproducing the line width of 0.35 μm as a sensitivity is observed with a scanning electron microscope. Then, the adhesiveness was evaluated based on the line width of the remaining thinnest line. That is, a pattern having a higher adhesion has a pattern with a finer line width remaining, whereas a pattern having a lower adhesion cannot be adhered to a substrate interface as a smaller line width, and the pattern is peeled off. Adhesion can be evaluated by the line width.

(3) Results The evaluation results are shown in Table 2. As shown in Table 2, the resins B to R of the present invention have excellent adhesion (minimum remaining line width) and pattern profile as compared with Comparative Samples S to Y.
In addition, the sensitivity of these resins had sufficient sensitivity that did not hinder the above test, reflecting that they had sufficient transparency to an ArF excimer laser (193 nm) light source. Samples B to R are different from Comparative Samples S to Y in that the repeating unit contains an acid-decomposable group having an inorganic value of 100 or more in the organic conceptual diagram. Further, since the poorly developed product of the comparative sample has not been developed, only a pattern other than the large pattern has been developed. Therefore, for convenience, the place where the line remains is read.

[0125]

[Table 2]

[0126]

As described above, the resin containing an acetal-type acid-decomposable group represented by the general formula [I] of the present invention is particularly suitable for light in a wavelength region of 170 nm to 220 nm and has good adhesion to a substrate. A positive photoresist composition which is excellent in thermal stability, has standard development suitability, and can obtain a favorable resist pattern profile can be provided.

Claims (5)

[Claims] 1. The action of an acid in a positive photoresist composition for deep ultraviolet light exposure, comprising a resin which decomposes under the action of an acid to increase solubility in alkali and a compound which generates an acid upon irradiation with actinic rays or radiation. A monomer whose partial structure represented by the following general formula [I] is directly or via a divalent organic linking group to a polymerizable carbon-carbon double bond: , As a repeating unit, wherein the composition is a positive photoresist composition for deep ultraviolet exposure. Embedded image In the formula, R ₁ represents a hydrogen atom or an alkyl group, and R ₂ represents
It represents an alkyl group substituted so that the numerical value of inorganicity in the organic conceptual diagram is 100 or more. 2. The far ultraviolet exposure according to claim 1, wherein the substituent R ₂ in the partial structure represented by the general formula [I] is an alkyl group having 1 to 12 carbon atoms. Positive photoresist composition. 3. The positive photoresist composition for deep ultraviolet exposure according to claim 1, wherein the partial structure represented by the general formula [I] is represented by the following general formula [II]. Stuff. Embedded image Wherein R ₃ , R ₄ and R ₅ are a hydrogen atom, an alkyl group,
Cycloalkyl group, hydroxyalkyl group, alkoxyalkyl group, hydroxyalkoxyalkyl group, acylaminoalkyl group, sulfoaminoalkyl group, carboxyl group, carboxyalkyl group, acylamino group, sulfoamino group, sulfamoyl group, sulfoaminosulfoalkyl group, carbamoyl Group, alkoxy group, acyl group,
Represents a hydroxyl group or a cyano group. 4. The method according to claim 1, wherein the wavelength of the actinic ray or radiation to be exposed is 170 to 220 nm.
4. The positive photoresist composition for deep ultraviolet exposure according to 3. 5. An optical system according to claim 1, wherein the transmission optical density per one micron of the thickness of the coating is 1.0 or less for an actinic ray having a wavelength of 193 nm.
5. The positive photoresist composition for deep UV exposure according to item 4.