JP2001042531A - Positive type radiation sensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a positive type radiation sensitive resin composition having high sensitivity and high resolving power and not causing a dimensional change due to PED (post exposure time delay). SOLUTION: Thus positive type radiation sensitive resin composition contains (a) a polymer obtained by reacting a polymer having phenolic hydroxyl groups with an alkyl vinyl ether compound and an alcohol compound under the presence of an acidic catalyst, (b) a compound which generates an acid when being irradiated with active light or radiation and (c) a solvent. The polymer (a) is decomposed by the action of the generated acid and increases its solubility to an alkali developing solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive-type radiation-sensitive resin composition which can be suitably used for manufacturing semiconductor integrated circuit elements, masks for manufacturing integrated circuits, printed wiring boards, liquid crystal panels and the like.

[0002]

2. Description of the Related Art As a positive radiation-sensitive resin composition, there is a chemically amplified resist composition described in US Pat. No. 4,491,628, European Patent No. 29,139 and the like. The chemically amplified positive resist composition generates an acid in the exposed area by irradiation with radiation such as far ultraviolet light, and the acid-catalyzed reaction causes the active and non-irradiated parts of the active radiation to dissolve in the developing solution. Is a pattern forming material for forming a pattern on a substrate by changing the pattern.

[0003] Examples of such a combination include a combination of a compound that generates an acid by photolysis with an acetal or an O, N-acetal compound (JP-A-48-89003), a combination of an orthoester or an amide acetal compound ( JP-A-51-120714), combination with a polymer having an acetal or ketal group in the main chain (JP-A-53-133429), combination with an enol ether compound (JP-A-55-12995), Combination with an acylimino carbonate compound (JP-A-55-12623)
6), 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).
Gazette), a combination with a silyl ester compound (JP-A-60
-10247) and a combination with a silyl ether compound (JP-A-60-37549, JP-A-60-12)
1446). 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 to solubilize 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-63-362
40, JP-A-63-250642, Polym.Eng.
Sce., 23, 12 (1983); ACS. Sym. 242, 11 (198
4); Semiconductor World 1987, November, p. 91; M
acromolecules, 21, 21475 (1988); SPIE, 920, 42
Page (1988) and the like, a compound capable of generating an acid upon exposure to light and a tertiary or secondary carbon (for example, t-butyl, 2-
(Cyclohexenyl) in combination with an ester or carbonate compound. These systems also have high sensitivity and have a lower absorption in the Deep-UV region than the naphthoquinonediazide / novolak resin system, and thus can be effective systems for shortening the wavelength of the light source.

Japanese Patent Application Laid-Open No. Hei 2-19847 discloses poly (p
(Hydroxystyrene) is disclosed which contains a resin in which the phenolic hydroxyl group of the compound is completely or partially protected by a tetrahydropyranyl group. Japanese Patent Application Laid-Open No. 219957/1992 also discloses a photoresist composition characterized by containing a resin in which 20 to 70% of the phenolic hydroxyl groups of poly (p-hydroxystyrene) are substituted with acetal groups. Have been. Further, JP-A-5-24968
JP-A No. 2 also discloses a photoresist composition using a similar acetal-protected resin.

Further, JP-A-8-123032 discloses a photoresist composition using a terpolymer containing a group substituted with an acetal group. Further, Japanese Patent Application Laid-Open
-113667, JP-A-6-266112, JP-A-6-289608, JP-A-7-209
No. 868 discloses a photoresist composition comprising a hydroxystyrene and a (meth) acrylate copolymer. Also, JP-A-9-297396 discloses that
It contains a polymer having a group decomposable by an acid, a radiation-sensitive acid generator, a compound obtained by acetalizing a hydrogen atom of a phenolic hydroxyl group in a compound having a molecular weight of less than 1000 having a phenolic hydroxyl group, and an acid diffusion controlling material. A radiation-sensitive resin composition is described. It is described that this composition is excellent in resolving power, cross-sectional shape and focus tolerance of a contact hole.

On the other hand, J. A. Photopolym. Sci.
Tech. , 11 (3) 431 (1998). It has been reported that a desired acetal group can be introduced into an alkali-soluble resin by using the acetal exchange method of Malik et al. The acetal exchange method has an advantage that various acetal groups can be introduced by selecting an alcohol species.

[0008]

However, according to the findings of the present inventors, when an alkali-soluble resin having an acetal group introduced by the acetal exchange method is used in a positive radiation-sensitive resin composition, PED ( Post Exposure T
ime De1ay) caused dimensional fluctuations and became a problem. An object of the present invention is to use PED (Post Exposu) using an acid-decomposable polymer obtained by an acetal exchange method.
An object of the present invention is to provide a positive-type radiation-sensitive resin composition having a high resolution without causing a dimensional change due to re time delay.

[0009]

Means for Solving the Problems In view of the present situation, the present inventors have conducted intensive studies. As a result, a low-molecular-weight acetal compound is by-produced by the acetal exchange method, and this low-molecular-weight acetal compound causes dimensional fluctuation due to PED. By reducing the number of by-product low molecular acetal compounds having a molecular weight of 1000 or less, PE
The present inventors have found that a stable positive-type radiation-sensitive resin composition with reduced dimensional fluctuation due to D can be provided, and have completed the present invention. That is, the positive radiation-sensitive resin composition according to the present invention has the following constitution.

(1) (a) A polymer having a phenolic hydroxyl group, an alkyl vinyl ether compound, and an alcohol compound are reacted in the presence of an acidic catalyst, and a low-molecular-weight acetal compound having a molecular weight of 1,000 or less produced by the reaction is removed. It contains the obtained polymer which is decomposed by the action of an acid to increase the solubility in an alkali developer, (b) a compound which generates an acid upon irradiation with actinic rays or radiation, and (c) a solvent. Positive radiation-sensitive resin composition.

(2) The acidic catalyst used in the reaction is neutralized with an organic base before or after removing the low molecular weight acetal compound having a molecular weight of 1,000 or less, which is a by-product of the polymer (a). The positive-type radiation-sensitive resin composition according to the above (1), wherein the composition is prepared.

(3) A method of removing the low molecular acetal compound by mixing a solution in which the polymer (a) is dissolved and a poor solvent for the polymer (a) to precipitate or separate the polymer (a). The positive-type radiation-sensitive resin composition according to the above (1) or (2), wherein

(4) The content of the low molecular weight acetal compound having a molecular weight of 1,000 or less contained in the polymer (a) is 2% by weight or less based on the total weight of the polymer (a). The positive-type radiation-sensitive resin composition according to any one of (1) to (3).

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The positive-type radiation-sensitive resin composition of the present invention comprises an acid-decomposable polymer (a) prepared by the above method, a compound (b) that generates an acid upon irradiation with actinic rays or radiation, and a solvent (c).
At least. Hereinafter, each component blended in the positive-type radiation-sensitive resin composition of the present invention will be described.

(A) A polymer which is decomposed by the action of an acid to increase the solubility in an alkali developing solution (hereinafter, also referred to as “acid-decomposable polymer (a)”). It is a polymer that is decomposed by the acid generated from the photoacid generator upon irradiation with radiation and solubilized in an alkaline developer. The acid-decomposable polymer (a) is preferably a polymer having an alkali-soluble group, in which the alkali-soluble group is protected by a group capable of decomposing by the action of an acid.

The acid-decomposable polymer (a) of the present invention is obtained by dissolving a polymer having a phenolic hydroxyl group, preferably in an organic solvent, and dehydrating the water in the system by azeotropic distillation or the like. An acetal exchange reaction can be carried out by adding an alkyl vinyl ether and an acid catalyst to introduce a desired acetal group into a phenolic hydroxyl group. The polymer having a phenolic hydroxyl group is preferably a polymer of hydroxystyrenes, and may be a copolymer with an acid-decomposable (meth) acrylate such as t-butyl acrylate or t-butyl methacrylate.

For the purpose of adjusting the alkali solubility of the acid-decomposable polymer (a), a non-acid-decomposable group can be introduced into the polymer having a phenolic hydroxyl group. Examples of the method of introducing a non-acid-decomposable group include a method of copolymerizing styrenes, non-acid-decomposable (meth) acrylic esters, and non-acid-decomposable (meth) acrylic amides, and a method of introducing hydroxystyrenes. A method of protecting a hydroxyl group with a non-acid-decomposable substituent is preferred. As the substituent of the non-acid-decomposable group,
An acetyl group, a mesyl group, a toluenesulfonyl group and the like are preferable, but not limited thereto.

The styrenes include styrene, chlorostyrene, dichlorostyrene, bromostyrene, dibromostyrene, iodostyrene, methylstyrene, dimethylstyrene, ethylstyrene, isopropylstyrene, methoxystyrene, ethoxystyrene, phenylstyrene, and t-butyl. Styrene, t-butoxystyrene and the like can be mentioned, but styrene, methylstyrene, t-butylstyrene and t-butoxystyrene are particularly preferred. Examples of the non-acid-decomposable (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, allyl (meth) acrylate, and glycidyl (meth) acrylate. Benzyl (meth) acrylate, hydroxyethyl (meth) acrylate and the like. Non-acid-decomposable (meth) acrylamides include (meth) acrylamide, (meth) acrylamide
Acrylic acid phenylamide, (meth) acrylic acid isopropylamide and the like can be mentioned.

Further, examples of the copolymerizable monomer include maleic acid derivatives, maleic anhydride derivatives, (meth) acrylonitrile, vinylpyrrolidone, vinylpyridine, vinyl acetate and the like.

As described above, the acid-decomposable polymer (a)
It is possible to introduce a copolymer component and / or a non-acid-decomposable group into the polymer having a phenolic hydroxyl group as long as the alkali solubility of the polymer is adjusted and the alkali developability is not impaired. It is desirable from the viewpoint of dry etching resistance and sensitivity that the hydroxystyrene component accounts for 60 mol% or more, preferably 70 mol% or more of the components constituting the polymer having a phenolic hydroxyl group.
The weight average molecular weight of the trunk polymer (polymer having a phenolic hydroxyl group) can be measured by gel permeation chromatography (GPC) as a molecular weight (Mw) in terms of polystyrene.
00 to 200,000 and 2,500 to 30,00
0 is particularly preferred. If the molecular weight exceeds 200,000, the solubility tends to be poor and the resolving power tends to decrease.

As the alkyl vinyl ether compound used for acetal exchange, a compound represented by the following general formula (I) is desirable. R ₁ —O—CH ＝ CH ₂ General formula (I) In the formula, R ₁ is a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms which may have a substituent. Examples of the linear, branched or cyclic alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, t-butyl group and hexyl. And alkyl groups such as a 2-ethylhexyl group, an octyl group, a cyclopropyl group, a cyclopentyl group and a cyclohexyl group.

Specific examples of the compound represented by the general formula (I) include ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, t-butyl vinyl ether, cyclohexyl vinyl ether, n-hexyl vinyl ether and the like. However, any one may be used as long as it substantially causes an acetal exchange reaction between the alcohol and the phenolic hydroxyl group in the polymer, and is not limited to the above. Among the above, t-butyl vinyl ether, isopropyl vinyl ether, and cyclohexyl vinyl ether are preferred,
-Butyl vinyl ether is more preferred.

The alcohol compound used in the acetal exchange reaction may be any of primary, secondary and tertiary alcohols, but primary and secondary alcohols are more preferred. In addition, two or more hydroxyl groups may be present in one molecule, but when a plurality of hydroxyl groups are present, crosslinking is introduced between the polymers. These alcohols may be used as a mixture of two or more as necessary.

As the monohydric alcohol, methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, n-amyl alcohol, isoamyl alcohol, hexyl alcohol, heptyl alcohol Alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, tridecyl alcohol, myristyl alcohol, pendadecyl alcohol, cetyl alcohol, heptadecyl alcohol, aliphatic saturated alcohols such as stearyl alcohol, allyl alcohol, crotyl Aliphatic unsaturated alcohols such as alcohol, propapyl alcohol, and hydroxyethyl (meth) acrylate Lumpur, cyclopentanol, cyclohexanol, cyclohexane methanol, cyclohexane ethanol, adamantyl ethyl alcohol,
Alicyclic group-containing alcohols such as norbornene methanol,
Examples thereof include aromatic alcohols such as benzyl alcohol, phenethyl alcohol and cinnamyl alcohol, and heterocyclic alcohols such as furfuryl alcohol. As the dihydric alcohol compound, ethylene glycol, 1,3
-Propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 3 , 3-dimethyl-1,
2-butanediol, 1,5-pentanediol, 1,
4-pentanediol, 2,4-pentanediol,
1,6-hexanediol, 1,5-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,2-cyclopentanediol, 1,3-cyclopentanediol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanediol, dicyclohexyl-4,4′-diol, 1,4-cyclooctanediol, binanediol, 1,5-decalindiol,
2-cyclohexene-1,4-diol and the like.

The amount of the alkyl vinyl ether compound and the alcohol compound used in the reaction is preferably 5 mol% to 95 mol%, more preferably 5 mol% to the phenolic hydroxyl group in the polymer having a phenolic hydroxyl group. Is from 10 mol% to 60 mol%, more preferably from 15 mol% to 50 mol%. Further, the usage ratio (weight) of the alcohol compound to the alkyl vinyl ether compound is preferably 70% to 130%.

The organic solvent used in the reaction is not particularly limited as long as it is an inert solvent. Propylene glycol methyl ether acetate (PGMEA), 2-heptanone, ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, tetrahydrofuran And the like. Among them, PGMEA and 2-heptanone are preferred. The reaction solvent is usually 100 to 100 parts by weight based on 100 parts by weight of the polymer having a phenolic hydroxyl group.
0 parts by weight are used.

The acetal exchange reaction proceeds according to the following scheme.

[0028]

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At this time, a low molecular acetal represented by the above formula (II) is by-produced. The low-molecular acetal represented by the above formula (II) is composed of R ₁ in vinyl ether and R _{2 in} alcohol.
Are by-products formed by acetalization by acetal exchange reaction. For example, the following low molecular acetal is by-produced from t-butyl vinyl ether and benzyl alcohol.

[0030]

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By removing or reducing the low molecular acetal compound represented by the formula (II), the PED stability of the positive radiation-sensitive resin composition of the present invention is improved.

As a method for removing the low molecular acetal, a poor solvent for the acid-decomposable polymer (a) is added to the reaction solution containing the acid-decomposable polymer (a) formed after the reaction, and the supernatant is decanted. A method of removing by a method or the like is preferable. By this method, low-molecular-weight acetal with a molecular weight of 1000 or less can be reduced.

As the poor solvent, acid-decomposable polymer (a)
Is appropriately selected depending on the type of the solvent, but non-polar solvents such as hexane, heptane, xylene, and toluene are preferably used. The amount of the poor solvent used is preferably 3 to 30 times the total weight of the acid-decomposable polymer (a).

In this solvent separation, the low molecular weight component of the acid-decomposable polymer (a) may be removed simultaneously with the low molecular weight acetal, and the degree of dispersion (molecular weight distribution) of the polymer is reduced (narrowed). This is preferable because the resolution is further improved.

As a method for removing low molecular acetal, a liquid-liquid extraction method, a column separation method, a membrane separation method and the like are similarly effective.

The removal of the low molecular weight acetal compound having a molecular weight of 1,000 or less needs to be reduced to the extent that PED is substantially improved. Generally, the amount contained in the acid-decomposable polymer (a) is as follows: 2% by weight or less, especially 1%
Preferably, it is reduced to not more than% by weight. The residual amount of the low molecular acetal can be easily quantified by measurement such as HPLC and GPC.

The acid-decomposable polymer (a) can be used alone or in combination of two or more. Further, a combination of an acid-decomposable polymer (a) synthesized from two or more kinds of polymers having phenolic hydroxyl groups having different molecular weights and composition ratios of a polymer having a phenolic hydroxyl group, and two or more kinds of acid decomposition having different acetal protection rates Combinations of conductive polymers can also be selected to exhibit sensitivity, resolution, profile and other resist properties.

The acid-decomposable polymer (a) is synthesized by dissolving a polymer having a phenolic hydroxyl group in the organic solvent (solvent inert to the acetalization reaction) shown above,
If necessary, water in the system is removed by distillation under reduced pressure or the like, and a vinyl ether compound and an alcohol compound are added. The acetal exchange reaction proceeds by the addition of an acidic catalyst. As the acidic catalyst, either an inorganic acid or an organic acid can be used. Organic acids are preferred because they have no residual metal impurities,
More preferred are p-toluenesulfonic acid and pyridinium p-toluenesulfonic acid. For the purpose of stopping the acetal exchange reaction, it is preferable to carry out neutralization with a base compound. If this neutralization is not carried out, the acid may remain and the storage stability of the resist may be impaired. The base compound to be used is not particularly limited as long as the acid as a catalyst added is neutralized and a salt is removed in a water washing step. Among them, organic base compounds are preferable because there are no residual metal impurities,
Specific examples include triethylamine, trimethylamine, pyridine, aminopyridine, piperazine, imidazole and the like, and triethylamine and pyridine are particularly preferred. After the acetal exchange reaction is completed and neutralized, it is preferable to remove salts remaining in the system using ultrapure water or the like. This operation may be performed before or after removing the low molecular weight acetal compound having a molecular weight of 1000 or less.

(B) Compound that generates an acid upon irradiation with actinic rays or radiation (hereinafter, also referred to as "photoacid generator (b)") The photoacid generator (b) used in the present invention includes light Photoinitiators for cationic polymerization, photoinitiators for photoradical polymerization, photodecolorants for dyes, photochromic agents, or known light used in microresist and the like (ultraviolet rays of 400 to 200 nm, far ultraviolet rays, especially Preferably, g line, h line, i line, K
rF excimer laser light), an ArF excimer laser light, an electron beam, an X-ray, a compound generating an acid by a molecular beam or an ion beam, and a mixture thereof can be appropriately selected and used.

Other compounds which generate an acid upon irradiation with actinic rays or radiation used in the present invention include, for example, diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, arsonium salts and the like. Onium salts, organic halogen compounds, organometallic / organic halides, photoacid generators having o-nitrobenzyl-type protecting groups, iminosulfone-
And the like, a compound which generates sulfonic acid by photolysis, such as diazotosulfone, diazoketosulfone, and diazodisulfone compound. Further, a group in which an acid is generated by such light or a compound in which a compound is introduced into a main chain or a side chain of a polymer can be used.

Further, VN.R.Pillai, Synthesis, (1), 1 (19
80), A. Abad etal, Tetrahedron Lett., (47) 4555 (197
1), DHR Barton et al., J. Chem. Soc., (C), 329 (1970),
Compounds that generate an acid by light described in U.S. Pat. No. 3,779,778 and European Patent 126,712 can also be used.

Among the compounds capable of decomposing upon irradiation with actinic rays or radiation to generate an acid, those which are used particularly effectively 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).

[0043]

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

[0045]

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[0046]

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

[0048]

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Here, the formulas Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aryl group. R ²⁰³ , R ²⁰⁴ , R
²⁰⁵ is each independently a substituted or unsubstituted alkyl group,
Indicates an aryl group.

Z ⁻ represents a counter anion, for example, BF ₄ ⁻ ,
_{^{AsF 6 -, PF 6 -,}} SbF 6 -, SiF 6 2-, ClO 4 -,
CF ₃ SO ₃ ^-, etc. perfluoroalkane sulfonate anion, pentafluorobenzenesulfonic acid anion, condensed polynuclear aromatic sulfonic acid anion such as naphthalene-1-sulfonic acid anion, anthraquinone sulfonic acid anion, a sulfonic acid group-containing dyes Examples include, but are not limited to:

Further, two of R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ and Ar ¹ and Ar ² may be bonded through a single bond or a substituent.

Specific examples include the following compounds, but are not limited thereto.

[0053]

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[0054]

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[0055]

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[0056]

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[0057]

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[0058]

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The above onium salts represented by the general formulas (PAG3) and (PAG4) are known, for example, JWKnapczyk
etal, J. Am. Chem. Soc., 91, 145 (1969), ALMaycok eta
l, J. Org. Chem., 35, 2532, (1970), E. Goethas et al., Bul
l. Soc. Chem. Belg., 73,546, (1964), HM Leicester J.
Ame.Chem.Soc., 51,3587 (1929), JVCrivello etal, JP
olym.Chem.Ed., 18,2677 (1980), U.S. Pat.No. 2,807,648
No. 4,247,473, JP-A-53-101,331 and the like.

(3) Disulfone derivatives represented by the following formula (PAG5) or iminosulfonate derivatives represented by the following formula (PAG6).

[0061]

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Where Ar^Three, Ar^FourAre each independently substituted
Or an unsubstituted aryl group. R ²⁰⁶Is replaced or
It represents an unsubstituted alkyl group or aryl group. A is a substitution
Or unsubstituted alkylene, alkenylene, arylene
Shows a substituent group. Specific examples include the compounds shown below.
However, the present invention is not limited to these.

[0063]

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[0064]

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[0065]

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(4) A diazodisulfone derivative represented by the following general formula (PAG7).

[0067]

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Here, R represents a linear, branched or cyclic alkyl group or an optionally substituted aryl group.
Specific examples include the following compounds, but are not limited thereto.

[0069]

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The amount of the compound which decomposes upon irradiation with actinic rays or radiation to generate an acid is usually in the range of 0.001 to 40% by weight based on the solid content in the composition, and is preferably used. Is used in the range of 0.01 to 20% by weight, more preferably 0.1 to 5% by weight. If the amount of the compound that decomposes upon irradiation with actinic rays or radiation to generate an acid is less than 0.001% by weight, the sensitivity is low, and if the amount is more than 40% by weight, the light absorption of the resist is high. This is not preferable because the profile is deteriorated and the process (especially baking) margin is narrowed.

(C) Solvent Component The composition of the present invention is dissolved in a solvent that dissolves the above-described components and optional components described below, and coated on a support. As the solvent used here, ethylene dichloride, cyclohexanone, cyclopentanone, 2-heptanone, γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl ether acetate , Propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, toluene, ethyl acetate,
Methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate,
Preferred are ethyl pyruvate, propyl pyruvate, N, N-dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, tetrahydrofuran and the like. These solvents can be used alone or in combination of two or more.

Among the above, preferred solvents are 2-
Heptanone, γ-butyrolactone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate , N-methylpyrrolidone and tetrahydrofuran.

(Other Components Used in the Present Invention) The positive radiation-sensitive resin composition of the present invention does not contain an acid-decomposable group other than the acid-decomposable polymer (a) as a resin component. An alkali-soluble resin can be blended, whereby the sensitivity is improved. An alkali-soluble resin containing no acid-decomposable group (hereinafter, simply referred to as “alkali-soluble resin”) is a resin that is soluble in alkali, and preferably includes polyhydroxystyrene, novolak resin, and derivatives thereof. A copolymer resin containing a p-hydroxystyrene unit can also be used as long as it is alkali-soluble. Among them, poly (p-hydroxystyrene), poly (p- / m-hydroxystyrene) copolymer, poly (p- / o-hydroxystyrene) copolymer, poly (p-hydroxystyrene / styrene) copolymer Coalescing is preferably used. Furthermore, poly (4-hydroxy-3)
-Methylstyrene), poly (4-hydroxy-3,5-)
Poly (alkyl-substituted hydroxystyrene) resins such as dimethylstyrene) and resins in which some of the phenolic hydroxyl groups of the above resins are alkylated or acetylated are also preferably used as long as they are alkali-soluble.

Further, when a part of the phenol nucleus of the resin (30 mol% or less of all phenol nuclei) is hydrogenated, the transparency of the resin is improved, and the sensitivity, the resolution, and the rectangular formation of the profile are improved. preferable. In the present invention,
The amount of the alkali-soluble resin not containing the acid-decomposable group in the composition is preferably 2 to 60% by weight, more preferably 5 to 30% by weight, based on the total weight of the solid content of the composition. %.

The positive-type radiation-sensitive resin composition of the present invention may further contain an acid-decomposable dissolution-promoting compound, a dye,
A plasticizer, a surfactant, a photosensitizer, an organic basic compound, a compound that promotes solubility in a developer, and the like can be contained. The positive-type radiation-sensitive resin composition of the present invention includes a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant, silicon-based surfactant and surfactant containing both fluorine atom and silicon atom). Can be contained. As these surfactants, for example, JP-A-62-36663, JP-A-61-226746, JP-A-61-2267
No. 45, JP-A-62-170950, JP-A-63-34540, JP-A-7
Surfactants described in JP-A-230165, JP-A-8-62834, JP-A-9-54432 and JP-A-9-5988, and the following commercially available surfactants can be used as they are.

Examples of commercially available surfactants that can be used include, for example, F-Top EF301 and EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florado FC430 and 431 (manufactured by Sumitomo 3M Limited), Megafac F171, F173, and F176. F189, R08 (Dainippon Ink Co., Ltd.)
Manufactured), Surflon S-382, SC101, 102, 103, 104, 10
5, 106 (manufactured by Asahi Glass Co., Ltd.) and the like. In addition, polysiloxane polymer KP-341 (Shin-Etsu Chemical Co., Ltd.)
Can also be used as a silicon-based surfactant. The amount of the surfactant is usually 0.01% by weight to 2% by weight per 100% by weight of the solid content in the composition of the present invention,
Preferably it is 0.01 to 1% by weight. These surfactants can be used alone or in combination of two or more.

An organic basic compound can be used in the composition of the present invention. This is preferable because the storage stability is improved and the line width change due to PED is reduced. Preferred organic basic compounds that can be used in the present invention are compounds that are more basic than phenol. Among them, a nitrogen-containing basic compound is preferable. Preferred chemical environments include the structures of the following formulas (A) to (E).

[0078]

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Here, R ²⁵⁰ , R ²⁵¹ and R ²⁵² are the same or different and each represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms,
An aminoalkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, wherein R ²⁵¹ and R ²⁵² are bonded to each other to form a ring; It may be formed.

[0080]

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Wherein R ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R
²⁵⁶ is the same or different and represents an alkyl group having 1 to 6 carbon atoms.) A more preferred compound is a nitrogen-containing cyclic compound or a nitrogen-containing basic compound having two or more nitrogen atoms having different chemical environments in one molecule. is there. The nitrogen-containing cyclic compound more preferably has a polycyclic structure. Preferred specific examples of the nitrogen-containing polycyclic compound include a compound represented by the following general formula (F).

[0082]

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In the formula (F), Y and Z each independently represent a linear, branched or cyclic alkylene group which may contain a hetero atom and may be substituted. Here, examples of the hetero atom include a nitrogen atom, a sulfur atom, and an oxygen atom. The alkylene group preferably has 2 to 10 carbon atoms, and more preferably has 2 to 5 carbon atoms. Examples of the substituent of the alkylene group include an alkyl group having 1 to 6 carbon atoms, an aryl group, an alkenyl group, a halogen atom, and a halogen-substituted alkyl group. Further, specific examples of the compound represented by the general formula (F) include the following compounds.

[0084]

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Of the above, 1,8-diazabicyclo [5.4.0] undec-7-ene and 1,5-diazabicyclo [4.3.0] non-5-ene are particularly preferred.

The nitrogen-containing basic compound having two or more nitrogen atoms having different chemical environments in one molecule is particularly preferably a compound containing both a substituted or unsubstituted amino group and a ring structure containing a nitrogen atom. Or a compound having an alkylamino group. As particularly preferred compounds, guanidine, 1,1-dimethylguanidine, 1,1,3,
3, -tetramethylguanidine, 2-aminopyridine,
3-aminopyridine, 4-aminopyridine, 2-dimethylaminopyridine, 4-dimethylaminopyridine, 2-
Diethylaminopyridine, 2- (aminomethyl) pyridine, 2-amino-3-methylpyridine, 2-amino-4
-Methylpyridine, 2-amino-5-methylpyridine,
2-amino-6-methylpyridine, 3-aminoethylpyridine, 4-aminoethylpyridine, 3-aminopyrrolidine, piperazine, N- (2-aminoethyl) piperazine, N- (2-aminoethyl) piperidine, 4- Amino-2,2,6,6-tetramethylpiperidine, 4-piperidinopiperidine, 2-iminopiperidine, 1- (2-
Aminoethyl) pyrrolidine, pyrazole, 3-amino-
5-methylpyrazole, 5-amino-3-methyl-1-
p-tolylpyrazole, pyrazine, 2- (aminomethyl) -5-methylpyrazine, pyrimidine, 2,4-diaminopyrimidine, 4,6-dihydroxypyrimidine,
-Pyrazoline, 3-pyrazolin, N-aminomorpholine, N- (2-aminoethyl) morpholine, trimethylimidazole, triphenylimidazole, methyldiphenylimidazole, and the like, but are not limited thereto.

These nitrogen-containing basic compounds are used alone or in combination of two or more. The amount of the nitrogen-containing basic compound to be used is generally 0.001 to 10 parts by weight, preferably 0.01 to 5 parts by weight, per 100 parts by weight of the composition (solid content).
Parts by weight. If the amount is less than 0.001 part by weight, the above effects cannot be obtained. On the other hand, if it exceeds 10 parts by weight, the sensitivity tends to decrease and the developability of the unexposed part tends to deteriorate.

The compound capable of accelerating dissolution in a developer that can be used in the present invention includes two or more phenolic hydroxyl groups.
Or a molecular weight of 1,000 having at least one carboxy group
These are the following low molecular compounds. When it has a carboxy group, an alicyclic or aliphatic compound is preferable for the same reason as described above. The preferable addition amount of these dissolution promoting compounds is 2 to 50% by weight, more preferably 5 to 30% by weight, based on the polymer in the present invention. An addition amount exceeding 50% by weight is not preferable because new development defects such as development residue deterioration and pattern deformation during development occur.

Such phenol compounds having a molecular weight of 1,000 or less can be prepared by those skilled in the art by referring to the methods described in, for example, JP-A-4-122938, JP-A-2-28531, US Pat. No. 4,916,210, and EP 219294. It can be easily synthesized at Specific examples of the phenol compound are shown below, but the compounds that can be used in the present invention are not limited to these.

Resorcin, phloroglucin, 2, 3, 4
-Trihydroxybenzophenone, 2,3,4,4'-
Tetrahydroxybenzophenone, 2,3,4,3 ',
4 ', 5'-hexahydroxybenzophenone, acetone-pyrogallol condensation resin, fluoroglucoside,
4,2 ', 4'-biphenyltetrol, 4,4'-thiobis (1,3-dihydroxy) benzene, 2,2',
4,4'-tetrahydroxydiphenyl ether, 2,
2 ', 4,4'-tetrahydroxydiphenylsulfoxide, 2,2', 4,4'-tetrahydroxydiphenylsulfone, tris (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) Cyclohexane, 4,4- (α-methylbenzylidene) bisphenol, α, α ′, α ″ -tris (4-hydroxyphenyl) -1,3,5-triisopropylbenzene,
α, α ', α "-tris (4-hydroxyphenyl)-
1-ethyl-4-isopropylbenzene, 1,2,2-
Tris (hydroxyphenyl) propane, 1,1,2-
Tris (3,5-dimethyl-4-hydroxyphenyl)
Propane, 2,2,5,5-tetrakis (4-hydroxyphenyl) hexane, 1,2-tetrakis (4-hydroxyphenyl) ethane, 1,1,3-tris (hydroxyphenyl) butane, para [α, α , Α ', α'-tetrakis (4-hydroxyphenyl)]-xylene.

Suitable dyes include oil dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 60
3. Oil black BY, oil black BS, oil black T-505 (all manufactured by Orient Chemical Co., Ltd.), crystal violet (CI42555), methyl violet (CI42535), rhodamine B
(CI45170B), malachite green (CI42
000), methylene blue (CI52015) and the like.

In order to improve the acid generation rate by exposure, a photosensitizer as described below can be further added. Examples of suitable photosensitizers include benzophenone, p, p'-tetramethyldiaminobenzophenone,
p, p'-tetraethylethylaminobenzophenone,
2-chlorothioxanthone, anthrone, 9-ethoxyanthracene, anthracene, pyrene, perylene, phenothiazine, benzyl, acridine orange, benzoflavin, setoflavin-T, 9,10-diphenylanthracene, 9-fluorenone, acetophenone, phenanthrene, 2-nitro Fluorene, 5-nitroacenaphthene, benzoquinone, 2-chloro-4-nitroaniline, N-acetyl-p-nitroaniline, p-nitroaniline, N-acetyl-4-nitro-1-naphthylamine, picramide, anthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone 1,2-benzanthraquinone, 3-methyl-1,3-diaza-
1,9-benzanthrone, dibenzalacetone, 1,
2-naphthoquinone, 3,3′-carbonyl-bis (5,
7-dimethoxycarbonylcoumarin) and coronene, but are not limited thereto. These photosensitizers can also be used as a light absorbing agent for far ultraviolet light as a light source. In this case, the light absorbing agent exerts the effect of improving the standing wave by reducing the reflected light from the substrate and reducing the influence of multiple reflection in the resist film.

In the present invention, a surfactant other than the above-mentioned fluorine-based and / or silicon-based surfactants can be added. Specifically, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether,
Polyoxyethylene alkyl ethers such as polyoxyethylene cetyl ether and polyoxyethylene oleyl ether; polyoxyethylene alkyl allyl ethers such as polyoxyethylene octyl phenol ether and polyoxyethylene nonyl phenol ether; polyoxyethylene / polyoxypropylene block copolymer Sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan fatty acid esters such as sorbitan tristearate,
Polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tristearate, etc. Nonionic surfactants and the like. The amount of these surfactants is
Per 100% by weight of solids in the composition of the present invention,
It is at most 2% by weight, preferably at most 1% by weight. These surfactants may be added alone or in some combination.

The above composition is applied on a substrate (eg, silicon / silicon dioxide coating) used for the production of precision integrated circuit devices by an appropriate application method such as a spinner, a coater or the like, followed by pre-baking, and By exposing through a mask, performing post-baking and developing, a good resist pattern can be obtained. Here, the exposure light is preferably far ultraviolet light having a wavelength of 250 nm or less. Specifically, a KrF excimer laser (248n
m), an ArF excimer laser (193 nm), an F ₂ excimer laser (157 nm), X-rays, an electron beam, and the like.

Examples of the developer for the photosensitive composition of the present invention include:
Sodium hydroxide, potassium hydroxide, sodium carbonate,
Inorganic alkalis such as sodium silicate, sodium metasilicate and aqueous ammonia, primary amines such as ethylamine and n-propylamine, secondary amines such as diethylamine and di-n-butylamine, and triethylamine and methyldiethylamine Use alkaline aqueous solutions such as triamines, alcoholamines such as dimethylethanolamine and triethanolamine, quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide, and cyclic amines such as pyrrole and pichelidine. be able to. Further, an appropriate amount of an alcohol or a surfactant may be added to the above alkaline aqueous solution.

[0096]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples.

Synthetic Example 1 (Synthesis of polymer having phenolic hydroxyl group: resin R-1) 32.4 g (0.2 mol) of p-acetoxystyrene was dissolved in 120 ml of methanol, and the mixture was stirred under a stream of nitrogen.
Azobisisobutylnitrile (AIBN) 0.0
33 g was added, and stirring was continued for 12 hours to carry out polymerization.
Dilute hydrochloric acid was added to the reaction solution to cut off the acetoxy group, and then volatiles were distilled off under reduced pressure. The obtained resin was dissolved again in 150 ml of methanol and added to a large amount of water to obtain a white polymer. The operation of dissolving the polymer in methanol again and adding it to a large amount of water was repeated three times, and the obtained resin was dried in a vacuum dryer at 60 ° C. for 24 hours to obtain poly (p).
-Hydroxystyrene) (resin R-1). The weight average molecular weight of the obtained resin was 15,000.

Synthesis Example 2 (Synthesis of polymer having phenolic hydroxyl group: resin R-2) According to a conventional method, 35.25 g (0.2 mol) of p-tert-butoxystyrene monomer dehydrated and purified by distillation and p-tert- 2.42 g of butylstyrene (0.015
1 mol) was dissolved in 100 ml of tetrahydrofuran.
Under a nitrogen stream and stirring, at 33 ° C., 0.033 g of azobisisobutylnitrile (AIBN) was added three times every three hours, and finally, stirring was continued for another six hours to carry out a polymerization reaction. The reaction solution was poured into 1200 ml of hexane to precipitate a white resin. After drying the obtained resin,
It was dissolved in 150 ml of tetrahydrofuran. This is 4N
Hydrochloric acid was added, and the mixture was hydrolyzed by heating and refluxing for 6 hours, then reprecipitated in 5 L of ultrapure water, and the resin was separated by filtration.
Washed and dried. Further, the resultant was dissolved in 200 ml of tetrahydrofuran and dropped and reprecipitated in 5 L of ultrapure water with vigorous stirring. This reprecipitation operation was repeated three times. The obtained resin was dried in a vacuum dryer at 60 ° C. for 24 hours to obtain a poly (p).
-Hydroxystyrene / p-tert-butylstyrene) copolymer (resin R-2). The weight average molecular weight of the obtained resin was 10,000.

Synthesis Example 3 (Synthesis of polymer having phenolic hydroxyl group: resin R-3) 40 g (0.33 mol) of p-hydroxystyrene, 10.7 g (0.08 mol) of tert-butyl acrylate and 50 g of dioxane And 8 g of azobisisobutylnitrile (AIBN) was added, and the mixture was heated and stirred at 60 ° C. for 8 hours under a nitrogen stream. The reaction solution was poured into 1200 ml of hexane to precipitate a white resin. The resulting resin was dried, dissolved in acetone, dropped into 5 L of ultrapure water with vigorous stirring, and reprecipitated. This reprecipitation operation was repeated three times. The obtained resin was dried in a vacuum dryer at 60 ° C. for 24 hours to obtain a poly (p-hydroxystyrene / tert-butyl acrylate) copolymer (Resin R-3). The weight average molecular weight of the obtained resin was 21,000.

Synthesis Example 4 (acid-decomposable polymer (a): B-
1 / Synthesis of polymer C-1 before purification) Poly (p-hydroxystyrene) manufactured by Nippon Soda Co., Ltd.
(Resin R-4) 70 g of (molecular weight 8,000) propylene glycol methyl ether acetate (PGMEA)
The solution was dissolved in 320 g, and the pressure of the solution was reduced to 60 mm and 20 mmHg, and about 40 g of the solvent was distilled off together with the water remaining in the system. The solution was cooled to 20 ° C., and a solution of 23.36 g of t-butyl vinyl ether and 0.35 g of p-toluenesulfonic acid viridinium salt dissolved in 25.22 g of benzyl alcohol was added. After stirring was continued at 20 ° C. for 2 hours, 0.28 g of triethylamine was added to stop the reaction. 280 ml of ethyl acetate was added to the reaction mixture, and 140 ml of water and 12 ml of acetone were further added to perform an extraction operation. After repeating the washing extraction operation three times, 60
Distillation was performed at 20 ° C. and 20 mmHg to remove water in the system. When the low-molecular acetal in this solution was quantified by HPLC, 7% by weight of the low-molecular acetal based on the solid content of the polymer was found to remain. This polymer before purification is referred to as an acid-decomposable polymer (C-1). The concentration of this solution was adjusted to 20% with PGMEA, and 910 ml of xylene was added dropwise at 20 ° C. After stirring for 15 minutes, 30
After standing still, the upper layer was removed by decantation. Thereafter, 100 ml of acetone and 200 ml of PGMEA were added and dissolved, and the mixture was concentrated at 60 ° C. and 20 mmHg. The low-molecular acetal in the PGMEA solution of the obtained acid-decomposable polymer (B-1) was 0.5% by weight based on the solid content of the polymer.

Synthesis Examples 5 to 16 (Acid-decomposable polymer B-2)
-B-13 / Synthesis of polymers C-2 to C-13 before purification) An acid-decomposable polymer was synthesized in the same manner as in Synthesis Example 4 except that the trunk polymer, vinyl ether and alcohol shown in Table 1 were used. Reprecipitation purification with xylene was performed to reduce low molecular acetal components. Table 1 shows the results. Here, the acid-decomposable polymer before purification was C-2 to C-
It is assumed to be 13.

[0102]

[Table 1]

Synthesis Example 17 (Synthesis of Acid-Degradable Polymer B-14) The acid-decomposable polymer C-4 (before reprecipitation purification) synthesized by the method of Synthesis Example 7 was subjected to silica gel column chromatography (eluent PGM).
EA / hexane) to obtain a solution from which low molecular acetal components had been removed. After concentrating this acid-decomposable polymer solution,
It was dissolved in PGMEA to obtain an acid-decomposable polymer (B-14). The low molecular acetal in the polymer was 1% by weight based on the solid content of the polymer.

The solutions of the acid-decomposable polymers B-1 to B-14 and C-1 to C-13 were adjusted so that the solid content concentration in PGMEA was 20% by weight. Used for comparative examples.

Examples 1 to 14 and Comparative Examples 1 to 13 (Preparation and Evaluation of Photosensitive Composition) The components shown in Table 2 below were dissolved in 8.4 g of PGMEA.
The solution was filtered through a 0.1 μm filter to prepare a resist solution. All acid-decomposable polymers used 11.485 g of a 20% PGMEA solution. This resist solution is
Using a spin coater, apply uniformly on a silicon wafer that has been treated with hexamethyldisilazane,
And heat drying on a hot plate for 90 seconds.
A μm resist film was formed. A KrF excimer laser stepper (NA: 0.6
Using 3), pattern exposure is performed using a halftone contact hole mask having a transmittance of 6%.
Heated on a hot plate at 90 ° C. for 90 seconds. 2.3
The film was developed with an 8% aqueous solution of tetramethylammonium hydroxide at 23 ° C. for 60 seconds, rinsed with pure water for 30 seconds, and dried. Further, after the pattern exposure, the same development, rinsing, and drying were performed after being left for 5 hours to examine the influence of PED. The obtained pattern was observed with a scanning electron microscope, and the performance of the resist was evaluated as described below.

The sensitivity was determined by the minimum exposure energy (minimum exposure amount) at which a contact hole having a diameter of 0.23 μm on the mask gave a pattern having a diameter of 0.18 μm. The resolution is
It was represented by the limit resolution (contact hole diameter) that can be resolved with this minimum exposure. The PED was observed by observing the change in the diameter of the contact hole between the pattern developed immediately after exposure and the pattern developed by heating for 5 hours after exposure. , 1-2% change in diameter was observed.
A sample in which a change of 2 to 3% was recognized was represented by Δ, and a sample in which a change of 3% or more was indicated by X. The results are shown in Table 3.

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[Table 2]

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[0109]

[Table 3]

As shown in Table 3 above, the compositions of Examples of the present invention gave positive photoresists which were excellent in resolving power, were not affected by PED, and had no dimensional change over time. On the other hand, the composition of the comparative example was unsatisfactory because of the influence of PED.

[0111]

The positive radiation-sensitive resin composition of the present invention has a high resolution and the effect of PED is significantly reduced.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2H025 AA00 AA01 AA02 AB15 AB16 AB17 AB20 AC04 AC05 AC06 AC08 AD03 BE00 BG00 BJ10 CB17 CB41 CB45 CC03 FA17

Claims (4)

[Claims] 1. A method comprising: (a) reacting a polymer having a phenolic hydroxyl group, an alkyl vinyl ether compound, and an alcohol compound in the presence of an acidic catalyst, and removing a low-molecular-weight acetal compound having a molecular weight of 1,000 or less by-produced by the reaction. A positive polymer characterized by containing a polymer which is decomposed by the action of an acid to increase the solubility in an alkali developer, (b) a compound which generates an acid upon irradiation with actinic rays or radiation, and (c) a solvent. Type radiation-sensitive resin composition. 2. The polymer (a) is obtained by neutralizing an acidic catalyst used in the reaction with an organic base before or after removing a low-molecular-weight acetal compound having a molecular weight of 1000 or less by-produced by the reaction. The positive-type radiation-sensitive resin composition according to claim 1, wherein 3. The method for removing the low molecular acetal compound,
A solution in which the polymer (a) is dissolved and the polymer (a)
2. The method according to claim 1, wherein the polymer (a) is mixed with a poor solvent to precipitate or separate the polymer (a).
Or the positive radiation-sensitive resin composition according to 2. 4. The method according to claim 1, wherein the content of the low molecular weight acetal compound having a molecular weight of 1000 or less contained in the polymer (a) is 2% by weight or less based on the total weight of the polymer (a). The positive-type radiation-sensitive resin composition according to any one of claims 1 to 3.