JP2000292917A - Positive type resist composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure excellent sensitivity and to form a fine resist pattern having no roundish top and excellent in squareness by using a positive type resist composition containing a mixture of a specified triphenylsulfonium salt and a specified sulfonium salt in a specified ratio. SOLUTION: The positive type resist composition contains a polymer (A) having an acid dissociable group having alkali dissolution inhibiting capability and substituted for the hydrogen atom of a carboxyl group and a compound (B) which generates an acid when irradiated with a radiation. The solubility of polymer A to an aqueous alkali solution increases when the acid dissociable group is dissociated by the action of the acid generated by exposure. The compound B is a mixture of a triphenylsulfonium salt (b-1) having an optionally substituted benzene nucleus and a sulfonium salt (b-2) of the formula, wherein Ar is aryl and X is a 1-15C fluoroalkylsulfonate ion. The amount of the salt b-1 is 5-25 wt.% of b-2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemically amplified positive resist composition.

[0002]

2. Description of the Related Art At present, a chemically amplified resist for a KrF (248 nm) excimer laser has already been put to practical use for forming a resist pattern of 0.30 μm or less. On the other hand, lithography processes using an ArF (193 nm) excimer laser of 0.15 μm or less have been actively developed, and many proposals have been made on resists for ArF. For example, JP-A-9-230595,
JP-A-9-244247 proposes a resist composition using a polycyclic polyolefin resin having an acid dissociable group such as a tert-butyloxycarbonyl group or a 1-methyl-1-cyclohexyloxycarbonyl group. ing. Further, WO97 / 33198, JP-A-10-107
No. 39 and Japanese Patent Application Laid-Open No.
A resist using a resin obtained by copolymerizing norbornene having an acid-dissociable group such as an rt-butyloxycarbonyl group or a 1-methyl-1-cyclohexyloxycarbonyl group with maleic anhydride has been proposed. Furthermore, Japanese Patent Laid-Open No.
0-130340, JP-A-10-153864, JP-A-10-198035, JP-A-10-108
JP-A-207058, JP-A-10-207070, JP-A-10-218941, JP-A-10-2
JP-A-18947 also proposes a positive resist for ArF. As proposed in these publications, Ar
As the acid generator for the positive type resist for F, there are listed many onium salts such as iodonium salts and sulfonium salts, as well as halogen-containing organic compounds, diazoketone compounds, sulfone compounds and sulfonic acid compounds. Above all, onium salts such as triphenylsulfonium trifluoromethanesulfonate are particularly preferably used because the generated acid has high strength and excellent sensitivity.

[0003]

However, in the positive resist composition for ArF using such an onium salt as an acid generator, the top portion of a fine resist pattern of 0.15 μm or less is rounded and rectangular. There is a problem that it is inferior. On the other hand, an onium salt represented by the general formula (I) of the present invention is also described in JP-A-10-282573. However, there is a problem that the onium salt is inferior in sensitivity. Accordingly, an object of the present invention is to provide a positive resist composition for ArF, which has excellent sensitivity, does not have a rounded top portion of a fine resist pattern of 0.15 μm or less, and has excellent rectangularity of the resist pattern.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have been able to solve the above-mentioned conventional problems by mixing a specific heterogeneous acid generator at a predetermined ratio. . The invention of claim 1 is characterized in that (A) a hydrogen atom of a carboxyl group is replaced by an acid dissociable group having alkali dissolution inhibiting ability, and the acid dissociable group dissociates by the action of an acid generated by exposure to form an alkaline aqueous solution. In a positive resist composition comprising a polymer having increased solubility and (B) a compound capable of generating an acid upon irradiation with radiation, (B)
A mixture of (b-1) a triphenylsulfonium salt having a substituted or unsubstituted benzene nucleus and (b-2) a sulfonium salt represented by the following general formula (I),
5% to 25% by weight of (b-1) based on (b-2)
A positive resist composition characterized by being mixed in the range of

[0005]

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(Wherein, Ar represents an aryl group, and X ⁻ represents a fluoroalkylsulfonate ion having 1 to 15 carbon atoms.) The invention according to claim 2, wherein the component (A) comprises at least (a-
2. The positive resist composition according to claim 1, wherein the composition is a copolymer containing 1) a unit derived from a polycyclic olefin having an acid-dissociable group and (a-2) a unit derived from maleic anhydride. Is provided. The invention of claim 3 is
The positive resist composition according to claim 2, wherein the component (A) is a copolymer containing a unit represented by the following general formula (II).

[0007]

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(Wherein, R represents a hydrogen atom or a lower alkyl group, Y represents an acid dissociable group, and n is 0 or 1). The invention according to claim 4, wherein Y is a tertiary alkyl group or 4. A positive resist composition according to claim 3, which is an alkoxyalkyl group. The invention of claim 5 provides the positive resist composition according to claim 4, wherein Y is a 1-ethyl-1-cyclohexyl group. The invention according to claim 6 is the composition according to any one of claims 3 to 5, wherein (A) is a copolymer containing units represented by at least the general formula (II) and the following general formula (III). It is intended to provide a positive resist composition.

[0009]

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[0010] (wherein, R is as defined in the, R ¹ represents an alkyl group having at least one hydroxyl group, m is 0 or 1) The invention of claim 7, R ¹ is a lower of The positive resist composition according to claim 6, which is a monohydroxyalkyl group or a lower dihydroxyalkyl group. The invention of claim 8 provides the positive resist composition according to claim 7, wherein R ¹ is a 2-hydroxypropyl group or a 2,3-dihydroxybutyl group. The invention of claim 9 further comprises adding an organic carboxylic acid or an oxo acid of phosphorus or a derivative thereof to (A) in 0.01%.
9. The method according to claim 1, wherein the composition is contained in an amount of from 5 to 5% by weight.
The present invention provides a positive resist composition as described in the above item. The invention of claim 10 further comprises 0.01 to 5% by weight of an organic amine based on (A).
The present invention provides a positive resist composition according to any one of the above. The invention of claim 11 further comprises a bile acid ester having an acid-dissociable group in an amount of 1 to 10 relative to (A).
11. The method according to claim 1, wherein 0% by weight is blended.
The present invention provides a positive resist composition as described in the above item. The invention according to claim 12 is the positive resist composition according to claim 11, wherein the ester of bile acid is a tert-butyl ester of bile acid selected from the group consisting of cholic acid, deoxycholic acid, ursocholic acid and lithocholic acid. Is provided.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Component (A) Component (A) is a base resin component of a positive resist composition, in which a hydrogen atom of a carboxyl group is replaced by an acid-dissociable group having an alkali dissolution inhibiting ability. Is a polymer in which the acid dissociable group is dissociated by the action of an acid generated by the reaction, and the solubility in an aqueous alkaline solution is increased. Many such polymers have been proposed so far as described in the prior art,
Although not particularly limited, preferred polymers include copolymers containing at least (a-1) a unit derived from a polycyclic olefin having an acid-dissociable group and (a-2) a unit derived from maleic anhydride. Polymers.

As the acid dissociable group, those which have been known as the acid dissociable groups in the positive type resist for KrF and the positive type resist for ArF can be used without any particular limitation.
For example, a tertiary alkyloxycarbonyl group in which all alkyl groups such as a tert-butyloxycarbonyl group and a tert-amyloxycarbonyl group are aliphatic linear hydrocarbon groups; a 1-methyl-1-cyclohexyloxycarbonyl group Tertiary alkyl wherein an alkyl group such as a 1-ethyl-1-cyclohexyloxycarbonyl group, a 2-methyl-2-adamantyloxycarbonyl group is an aliphatic linear hydrocarbon group and an aliphatic cyclic hydrocarbon group; An oxycarbonyl group; a tetrahydrofuranyloxycarbonyl group,
Examples thereof include a cyclic or linear alkoxyalkyloxycarbonyl group such as a tetrahydropyranyloxycarbonyl group and a 1-ethoxyethyloxycarbonyl group.

Examples of the polycyclic olefin include bicyclo [2.2.1] -2-heptene (norbornene) and tetracyclo [4.4.0.1 ^2,5 . Examples thereof include polycyclic compounds having an ethylenic double bond such as [ ^17,10 ] -3-dodecene, but the present invention is not limited thereto. Preferably, the component (A) is at least a unit represented by the following general formula (II), or a copolymer containing this unit and a unit represented by the following general formula (III).

[0014]

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(Wherein, R represents a hydrogen atom or a lower alkyl group (for example, having 1 to 3 carbon atoms), Y represents an acid dissociable group, and n is 0 or 1)

[0016]

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Wherein R is the same as above, R ¹ is an alkyl group having at least one hydroxy, and m is 0 or 1.

In the general formula (II), Y is the above-mentioned acid dissociable group except for an ester moiety, and is particularly preferably a tert-butyl group, a 1-methyl-1-cyclohexyl group, a 1-ethyl group. A tertiary alkyl group such as -1-cyclohexyl group; an alkoxyalkyl group such as tetrahydropyranyl group;
An ethyl-1-cyclohexyl group is preferred because it has high sensitivity and can be easily synthesized at low cost.

In the general formula (III), R ¹ is a functional group for improving the adhesion between the silicon wafer or the silicon wafer provided with the inorganic film and the resist layer, and is an alkyl group having at least one hydroxyl group. In this case, although not particularly limited, for example, a lower monohydroxyalkyl group or a lower dihydroxyalkyl group having 1 to 10 carbon atoms and having one or two hydroxy groups is preferable. Specifically, a hydroxymethyl group,
A hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group, a dihydroxybutyl group, a hydroxypentyl group, etc .;
-Dihydroxybutyl groups are preferred. The unit represented by the general formula (II) or (III) is a product obtained by performing a Diels-Alder reaction between an acid-dissociable group-containing ester of acrylic acid or methacrylic acid and cyclopentadiene or dicyclopentadiene to obtain maleic anhydride. And a radical polymerization initiator such as benzoyl peroxide, 2,2'-azobisisobutyronitrile, acetyl peroxide, lauryl peroxide, and the like. Can be obtained. In this case, when cyclopentadiene is used, n and m correspond to 0, and when dicyclopentadiene is used, n and m correspond to 1.

The copolymerization ratio of maleic anhydride and polycyclic olefin monomer having an acid dissociable group in the general formula (II) or (III) is theoretically 50 mol% each.
However, in actuality, copolymerization between maleic anhydride and polycyclic olefin monomers also occurs. Therefore, the actual copolymerization ratio is 40 to 60 mol% of units derived from maleic anhydride, Derived unit 4
0 to 60 mol%. In addition, general formulas (II) and (III)
In the case of the copolymer represented by the general formula (II), 40 to 90 mol%, preferably 50 to 80 mol% of the unit of the general formula (II), and 10 to 60 mol%, preferably 20 to 50 mol% of the unit of the general formula (III) is there. When the unit of the general formula (II) is less than these ranges, the sensitivity is lowered, and when it is too large, the adhesion to the substrate is poor.
In addition, other than the unit represented by the general formula (II) or (III), a known monomer for the base resin of the conventional positive resist for ArF may be copolymerized as necessary. The weight average molecular weight of the component (A) of the present invention is 2,000.
〜15,000, preferably 3,000-6,000.

The compound that generates an acid upon irradiation with the component (B) is usually called an acid generator, and many compounds have been proposed as described in the prior art. In the present invention, as the acid generator, (b-1) a triphenylsulfonium salt having a substituted or unsubstituted benzene nucleus;
2) A mixture with a sulfonium salt represented by the following general formula (I), wherein (b-1) is 5% by weight based on (b-2).
The greatest feature is that the mixture is in the range of 25% by weight.

(B-1): The triphenylsulfonium salt having a substituted or unsubstituted benzene nucleus includes, for example, methyl, ethyl, propyl, butyl, tert-
Whether the benzene nucleus is substituted with a substituent such as a lower alkyl group such as a butyl group; a lower alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, or a tert-butoxy group; a halogen atom such as fluorine or chlorine; Or an unsubstituted triphenylsulfonium salt. The anion is not particularly limited,
Fluoroalkylsulfonic acid ions having 1 to 15 carbon atoms are preferred because of their strong acid strength.

Specifically, trifluoromethanesulfonate, nonafluorobutanesulfonate, heptadecafluorooctylsulfonate, camphorsulfonate and naphthalenesulfonate of triphenylsulfonium; trifluoromethanesulfonate, nonafluorobutanesulfonate of tri (4-methylphenyl) sulfonium , Heptadecafluorooctylsulfonate,
Camphorsulfonate and naphthalenesulfonate; 4-methylphenylbis (4-ethoxyphenyl)
Trifluoromethanesulfonate, nonafluorobutanesulfonate, heptadecafluorooctylsulfonate, camphorsulfonate and naphthalenesulfonate of sulfonium; 4-methoxyphenylbis (4-
Chlorophenyl) sulfonium trifluoromethanesulfonate, nonafluorobutanesulfonate, heptadecafluorooctylsulfonate, camphorsulfonate and naphthalenesulfonate.

(B-2) is represented by the following general formula:

[0025]

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(Wherein, Ar represents an aryl group, and X ⁻ represents a fluoroalkylsulfonic acid ion having 1 to 15 carbon atoms)

Examples of the aryl group include a substituted or unsubstituted phenyl group and a naphthyl group. Specifically, those represented by the following structural formulas are exemplified.

[0028]

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X ^- includes trifluoromethanesulfonate, nonafluorobutanesulfonate, heptadecafluorooctylsulfonate and the like.

The mixing ratio of (b-1) and (b-2) is
It is necessary to mix (b-1) in the range of 5% by weight to 25% by weight with respect to (b-2). Preferably, 10% by weight or more
20% by weight is good. If (b-1) is less than 5% by weight, the effect of improving sensitivity will be insufficient, and if it exceeds 25% by weight, the top of the resist pattern will be rounded and poor in rectangularity.

The onium salts (b-1) and (b-2) may be used as a mixture of two or more of them, to the extent that the object of the present invention is not impaired. Further, similarly, known acid generators may be mixed and used to such an extent that the object of the present invention is not impaired.

The component (B) is 0.1% of the component (A).
-20% by weight, preferably 1-10% by weight.

Various additives can be added to the composition of the present invention, if necessary. Examples of the additives include organic carboxylic acids, oxo acids of phosphorus or derivatives thereof, organic amines, esters of bile acids having an acid-dissociable group, and the like.

Examples of the organic carboxylic acid include, but are not particularly limited to, organic carboxylic acids such as saturated or unsaturated aliphatic carboxylic acids, alicyclic carboxylic acids, and aromatic carboxylic acids. Examples of the saturated aliphatic carboxylic acid include monovalent or polyvalent carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, and adipic acid. Examples of the unsaturated aliphatic carboxylic acid include acrylic acid, crotonic acid, isocrotonic acid, 3-butenoic acid, methacrylic acid, 4-pentenoic acid, propiolic acid, 2-butyric acid, maleic acid, fumaric acid, acetylene carboxylic acid, and the like. No. Examples of the alicyclic carboxylic acid include 1,1-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, and 1,3-cyclohexanedicarboxylic acid.
Cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,1-cyclohexyldiacetic acid and the like can be mentioned. As the aromatic carboxylic acid, p-hydroxybenzoic acid, o-hydroxybenzoic acid, 2-hydroxy-3
-Aromatic carboxylic acids having a substituent such as a hydroxyl group such as nitrobenzoic acid, phthalic acid, terephthalic acid and isophthalic acid, a nitro group and a carboxyl group.

As the oxo acid of phosphorus or its derivative, specifically, phosphoric acid such as phosphoric acid, phosphorous acid, di-n-butyl phosphate, diphenyl phosphate or the like or phosphoric acid or an ester thereof. Derivatives, phosphonic acid, phosphonic acid dimethyl ester, phosphonic acid di-n
Derivatives such as butyl esters, phenylphosphonic acids, phosphonic acid diphenyl esters, phosphonic acid dibenzyl esters and the like, and derivatives thereof such as phosphinic acids, phenylphosphinic acid and the like; Examples include, but are not limited to:

Of these, saturated aliphatic carboxylic acids such as malonic acid and succinic acid are preferable because of their high transmittance to ArF laser light and excellent resolution.

Examples of the organic amine include, but are not limited to, aliphatic amines, aromatic amines, and heterocyclic amines. As aliphatic amines,
Diethylamine, triethylamine, n-propylamine, di-n-propylamine, tri-n-propylamine, triisopropanolamine, isopropylamine, tributylamine, tripentylamine, triethanolamine, dipropanolamine, tripropanolamine, etc. No. As the aromatic amine, benzylamine, aniline, N-methylaniline, N, N-
Examples include dimethylaniline, o-methylaniline, m-methylaniline, p-methylaniline, N, N-diethylaniline, diphenylamine, di-p-tolylamine and the like. Examples of the heterocyclic amine include pyridine, o-methylpyridine, o-ethylpyridine, 2,3-dimethylpyridine, 4-ethyl-2-methylpyridine, 3-ethyl-4-methylpyridine and the like. Among these,
Aliphatic amines such as tripentylamine are preferable because of their high transmittance to ArF laser light and excellent resist pattern shape.

The mixing ratio of the organic carboxylic acid or the oxo acid of phosphorus or a derivative thereof is 0.01% with respect to the component (A).
-5% by weight, preferably 0.02-0.2% by weight. Within this range, the resolution and sensitivity are improved, which is preferable. The mixing ratio of the organic amine to the component (A)
It is in the range of 0.01 to 5% by weight, preferably 0.02 to 0.2% by weight. Within this range, the resist pattern shape and sensitivity are improved, which is preferable.

The ester of a bile acid having an acid dissociable group is A
Known as a dissolution inhibitor for a positive resist for rF,
It is not particularly limited. The ester includes, but is not limited to, tert-butyl ester, bile acid, tetrahydropyranyl ester, ethoxyethyl ester and the like of bile acids selected from cholic acid, deoxycholic acid, ursocholic acid, lithocholic acid and the like. Preferred is the tert-butyl ester of the bile acid. The ester is A
Since it shows high permeability to rF excimer laser and the acid dissociable group is dissociated by the action of the acid generated from the acid generator, it is used as needed to improve the contrast of the resist pattern. The mixing ratio is 1 to 100% by weight, preferably 5 to 20% by weight, based on the component (A).

The composition of the present invention may further contain, if necessary, compatible additives such as an antihalation agent and a surfactant.

The positive photoresist composition of the present invention is preferably used in the form of a solution obtained by dissolving the above-mentioned components in an appropriate solvent. Examples of such a solvent include solvents used in conventional positive photoresist compositions, for example, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone and 2-heptanone; ethylene glycol, propylene glycol , Diethylene glycol, ethylene glycol monoacetate, propylene glycol monoacetate, diethylene glycol monoacetate, or polyhydric alcohols such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof; such as dioxane Cyclic ethers; and ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate,
Esters such as ethyl pyruvate, methyl methoxypropionate and ethyl ethoxypropionate can be mentioned. These may be used alone or as a mixture of two or more.

An example of a preferred method of using the composition of the present invention is as follows. First, on a substrate such as a silicon wafer,
Apply the solution of the positive resist composition with a spinner or the like,
Dry to form a photosensitive layer, and then expose through a patterned photomask. Next, this is heated after exposure (PEB), and then developed with a developing solution, for example, an alkaline aqueous solution such as an aqueous solution of 1 to 10% by weight of tetramethylammonium hydroxide (TMAH). A faithful image (resist pattern) can be obtained. In order to further improve the resolution of the resist pattern, an inorganic or organic antireflection film may be interposed between the substrate and the photosensitive layer obtained by using the composition of the present invention. In addition, the effect of the present invention can be particularly enjoyed with the isolated pattern than with the line and space pattern.

[0043]

The most important feature of the present invention resides in that a specific heterogeneous onium salt is mixed at a predetermined ratio as an acid generator of a positive resist composition. In the prior art, there is no idea that a specific heterogeneous acid generator is positively mixed and used. For example, in the examples of the above-mentioned patent publication relating to the positive resist, the acid generator is almost solely compounded. In Example 8 of JP-A-10-218947,
A mixture of triphenylsulfonium triflate and dibutylnaphthylsulfonium triflate is described, but the mixing ratio and the like of both are not specifically described. The acid generator in the positive resist composition of the present invention comprises (b-1) a triphenylsulfonium salt having a substituted or unsubstituted benzene nucleus, and (b-2) a sulfonium represented by the above general formula (I). A mixture with salt,
5% to 25% by weight of (b-1) based on (b-2)
Are mixed in the range. (B-1) and (b-
2) is a known component, and for example, (b-2) is a component disclosed in
0-282673. However, when (b-1) is used alone, there is a problem that although the sensitivity is excellent, the top part of a fine resist pattern of 0.15 μm or less is rounded and is inferior in rectangularity. ) Alone has the problem that the sensitivity is inferior, although the rectangularity is excellent. According to the present invention, by mixing (b-1) and (b-2) at a specific ratio, it is possible to obtain only the advantages without expressing the disadvantages of both, that is, the sensitivity is reduced. It was possible to obtain a positive resist composition for ArF, which was excellent and had a fine resist pattern of 0.15 μm or less without a rounded top portion and excellent rectangularity of the resist pattern.

[0044]

The present invention will be further described below with reference to examples and comparative examples. Production Example 1 (Synthesis of polycyclic olefin monomer) 128 g of 1-ethyl-1-hydroxycyclohexane and 120 g of triethylamine were added to tetrahydrofuran 600
The mixture was stirred while cooling in an ice bath, and 91 g of acrylic acid chloride was added dropwise thereto over 10 minutes. Then, the temperature was slowly returned to room temperature, and the mixture was further stirred for 24 hours.
After thoroughly washing the reaction solution with water until neutral, tetrahydrofuran is removed with a rotary evaporator,
95 g of 1-ethyl 1-cyclohexyl acrylate (52% yield) was obtained. Next, 91 g of the obtained 1-ethyl-1-cyclohexyl acrylate was stirred while cooling in an ice bath, and 35 g of cyclopentadiene obtained by heating and thermally decomposing dicyclopentadiene at 40 ° C. was added to the mixture.
It was added dropwise over a period of minutes. After completion of the dropwise addition, the mixture was further stirred for 12 hours. This reaction solution is 1 mmHg, 115-117 ° C.
The compound having the following chemical formula was obtained by distillation under reduced pressure under the following conditions.

[0045]

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Et represents an ethyl group. The yield was 119 g (96% yield).

The analysis data of the proton MNR is: proton NMR; 0.8 ppm, 1.2 to 1.7 pp
m, 1.9 ppm, 2.2 ppm, 2.9 ppm, 3.
2 ppm, 6.0 ppm, 6.2 ppm; FTIR analysis data: 2972 cm^-1, 2936c
m^-1, 2863cm^-1, 2726cm^-1, 1449cm ^-1,
1336cm^-1, 1271cm^-1The compound was identified from the above analysis data.

Production Example 2 (Synthesis of Copolymer 1) In the same manner as in the Diels-Alder reaction of Production Example 1, 24.8 g of the polycyclic monomer obtained in Production Example 1, 2-hydroxypropyl acrylate was cycloadded. Pentadiene and Diels-Alder
13.0 g of the polycyclic monomer and 16.3 g of maleic anhydride obtained by the reaction were dissolved in 54.1 g of dioxane, and azobisisobutyronitrile was used as a reaction initiator.
4 g was added, and a polymerization reaction was performed at 70 ° C. for 24 hours. After completion of the reaction, the operation of pouring the reaction product into 1 liter of n-heptane to precipitate a polymer was repeated twice. The obtained copolymer was dried under reduced pressure at room temperature. Thus, a compound having the following chemical formula was obtained.

[0049]

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The yield of this copolymer was 26 g, the weight average molecular weight was 4,700, and the degree of dispersion was 1.8. In addition, x and y were 60 mol% and 40 mol%, respectively.

Example 1 100 parts by weight of copolymer 1 (component (A)) obtained in Production Example 2; 0.6 parts by weight of triphenylsulfonium trifluoromethanesulfonate (component (b-1)); Having 5 parts by weight of a sulfonium salt (((b-2) component);

[0052]

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As another component, tert-
7 parts by weight of butyl ester; 3 parts by weight of tert-butyl ester of lithocholic acid; 0.025 parts by weight of malonic acid; and 0.1 part by weight of tripentylamine are dissolved in 650 parts by weight of propylene glycol monomethyl ether acetate to form a positive photoresist. A solution was obtained.

Next, this positive photoresist solution was applied on a silicon wafer having a SiON film formed thereon using a spinner, and dried on a hot plate at 140 ° C. for 90 seconds to form a resist layer having a thickness of 0.4 μm. Was formed. Next, after selectively irradiating an ArF excimer laser (193 nm) with an ArF exposure apparatus (manufactured by Nikon Corporation), PEB treatment was performed at 130 ° C. for 90 seconds, and then a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 30 seconds. It was developed with a paddle, washed with water for 30 seconds and dried.

0.16 μm formed by the above operation
Was measured in units of mJ / cm ² (energy amount), and was found to be 50 mJ / cm ² . Also,
Although the resist pattern shape is slightly wider,
It was a good one with no film reduction and roundness in the top part.
Similarly, when the exposure time (sensitivity) for forming a 0.12 μm isolated resist pattern (line and space 1: 3) was measured, it was 36 mJ / cm ² . The shape of the resist pattern was very excellent in verticality, and was excellent in that the top portion had no film reduction and no roundness.

Example 2 In Example 1, (b-1) was added in an amount of 0.3 part by weight ((b-
(B-2) was replaced with the same amount of the following sulfonium salt

[0057]

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A positive photoresist solution was prepared in the same manner as in Example 1 except that the above process was replaced with the procedure of Example 1, and a resist pattern was formed under the same conditions as in Example 1. The exposure time (sensitivity) at which a 0.16 μm line-and-space pattern formed by such an operation is formed 1: 1 is defined as mJ / c.
When measured in m ² (energy amount) unit, 65 mJ
/ Cm ² . The shape of the resist pattern was slightly broader at the bottom, but was favorable without film reduction and roundness at the top portion. Similarly, 0.12 μm
Isolated resist pattern (line and space is 1:
When the exposure time (sensitivity) for forming 3) was measured,
It was 48 mJ / cm ² . The shape of the resist pattern was very excellent in verticality, and was excellent in that the top portion had no film reduction and no roundness.

Example 3 In Example 2, 0.8 part by weight of (b-1) ((b-
A positive resist solution was prepared in the same manner as in Example 2 except that the amount was changed to 16% by weight based on 2).
A resist pattern was formed under the same conditions as described above. The exposure time (sensitivity) at which a 0.16 μm line and space pattern formed by such an operation is formed 1: 1 is defined as m.
When measured in units of J / cm ² (energy amount), 4
It was 5 mJ / cm ² . The shape of the resist pattern was slightly broader at the bottom, but was favorable without film reduction and roundness at the top portion. Similarly, 0.12
The exposure time (sensitivity) for forming a μm isolated resist pattern (line and space 1: 3) was measured and found to be 32 mJ / cm ² . The shape of the resist pattern was slightly excellent in verticality although the top portion was slightly rounded.

Comparative Example 1 A positive resist solution was prepared in the same manner as in Example 2 except that (b-1) was omitted, and then a resist pattern was formed under the same conditions as in Example 1. did. When the exposure time (sensitivity) at which a 0.16 μm line and space pattern formed by such an operation was formed at a ratio of 1: 1 was measured in mJ / cm ² (energy amount), it was 70 mJ / cm ^2. Was. The shape of the resist pattern was slightly broader at the bottom, but was favorable without film reduction and roundness at the top portion. Similarly,
The exposure time (sensitivity) for forming an isolated resist pattern of 0.12 μm (line and space 1: 3) was measured and found to be 64 mJ / cm ² . In addition, the shape of the resist pattern was excellent in perpendicularity, but was defective with a reduced thickness and roundness at the top.

Comparative Example 2 A positive resist solution was prepared in the same manner as in Example 2 except that (b-2) was omitted and (b-1) was changed to 5 parts by weight. A resist pattern was formed under the same conditions as described above. The limit of the line-and-space pattern formed by such an operation is 0.20 μm, and the resist pattern shape is such that the top portion has a reduced film thickness and a large roundness, and is a defective shape close to a triangle. Similarly, an isolated resist pattern (line and space is 1:
Also in 3), the limit was 0.13 μm, and the resist pattern shape was such that the top portion was reduced in film thickness and the roundness was large, and the shape was poor like a triangle.

[0062]

According to the present invention, there is provided a positive resist composition for ArF which is excellent in sensitivity, has a fine resist pattern of 0.15 μm or less without being rounded, and has excellent rectangularity in the resist pattern. Is done.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hideo Haneda 150 Nakamaruko Nakahara-ku Kawasaki City Kanagawa Prefecture Inside Tokyo Ohka Kogyo Co., Ltd. F term in the company (reference) 2H025 AA01 AA03 AC04 AC08 AD03 BE07 BG00 CB08 CB10 CB41 CC20 4J038 CG081 CM011 CM021 GA02 JA35 JA55 JB01 JC17 JC22 JC29 NA18 PA17 PB09

Claims (12)

[Claims] (A) A hydrogen atom of a carboxyl group is replaced by an acid dissociable group having an alkali dissolution inhibiting ability, and the acid dissociable group is dissociated by the action of an acid generated by exposure, so that the solubility in an alkaline aqueous solution is reduced. In a positive resist composition comprising an increasing polymer and (B) a compound capable of generating an acid upon irradiation with radiation, the component (B) is (b-1)
A mixture of a triphenylsulfonium salt having a substituted or unsubstituted benzene nucleus and (b-2) a sulfonium salt represented by the following general formula (I), wherein (b-2) and (b-1) A) a positive resist composition, wherein 5) is mixed in a range of 5% by weight to 25% by weight. Embedded image (Wherein, Ar represents an aryl group, and X ⁻ has 1 to 1 carbon atoms.
5 represents a fluoroalkylsulfonic acid ion) 2. The copolymer (A) comprising at least (a-1) a unit derived from a polycyclic olefin having an acid-dissociable group and (a-2) a unit derived from maleic anhydride. The positive resist composition according to claim 1, which is a polymer. 3. The positive resist composition according to claim 2, wherein the component (A) is a copolymer containing a unit represented by the following general formula (II). Embedded image (Wherein, R represents a hydrogen atom or a lower alkyl group;
Represents an acid dissociable group, and n is 0 or 1.) 4. The positive resist composition according to claim 3, wherein Y is a tertiary alkyl group or an alkoxyalkyl group. 5. The positive resist composition according to claim 4, wherein Y is a 1-ethyl-1-cyclohexyl group. 6. The positive type according to claim 3, wherein (A) is a copolymer containing at least units represented by the general formula (II) and the following general formula (III). Resist composition. Embedded image (Wherein, R is as defined above, R ¹ represents an alkyl group having at least one hydroxyl group, and m is 0 or 1) 7. The positive resist composition according to claim 6, wherein R ¹ is a lower monohydroxyalkyl group or a lower dihydroxyalkyl group. 8. The positive resist composition according to claim 7, wherein R ¹ is a 2-hydroxypropyl group or a 2,3-dihydroxybutyl group. 9. The positive resist according to claim 1, further comprising 0.01 to 5% by weight of an organic carboxylic acid or an oxo acid of phosphorus or a derivative thereof based on (A). Composition. 10. An organic amine is added to (A) in an amount of 0.
The positive resist composition according to any one of claims 1 to 9, wherein the composition is contained in an amount of from 0.01 to 5% by weight. 11. The positive resist composition according to claim 1, further comprising a bile acid ester having an acid-dissociable group in an amount of 1 to 100% by weight based on (A). 12. The positive resist composition according to claim 11, wherein the ester of bile acid is a tert-butyl ester of bile acid selected from the group consisting of cholic acid, deoxycholic acid, ursocholic acid and lithocholic acid.