JP2000137327A - Chemically amplified positive resist composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photoresist composition good in sensitivity and resolution and especially high in adhesion to substrate by incorporating a resin having 2 kinds of specified polymerization units and an acid generator. SOLUTION: The photoresist composition contains the polymer having polymerization units each represented by the formula derived from a monomer of 2-alkyl-2-adamantyl (meth)acrylate and further polymerization units selected from 3-hydroxy-1-adamantyl (meth)acrylate and (meth)acrylonitrile monomers, and the acid generator. In the formula, R1 is H atom or methyl group; and R2 is an alkyl group. This resin is a copolymer of a 30-80 mol% 2-alkyl-2- adamantyl (meth)acrylate monomer and 20-70 mol% monomer selected from 3-hydroxy-1-adamantyl (meth)acrylate and (meth)acrylonitrile monomers.

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 used for fine processing of semiconductors.

[0002]

2. Description of the Related Art A lithography process using a resist composition is usually employed for fine processing of a semiconductor.
In lithography, the shorter the exposure wavelength, the higher the resolution in principle, as expressed by the Rayleigh diffraction limit equation. Exposure light sources for lithography used in the manufacture of semiconductors have become shorter each year, such as g-line with a wavelength of 436 nm, i-line with a wavelength of 365 nm, and a KrF excimer laser with a wavelength of 248 nm. ArF excimer laser is promising.

Since the life of a lens used in an ArF excimer laser exposure machine is shorter than that of a lens for a conventional exposure light source, it is desirable that exposure time to an ArF excimer laser beam be as short as possible. For this purpose, since it is necessary to increase the sensitivity of the resist, a so-called chemically amplified resist containing a resin having a group that is cleaved by the acid utilizing the catalytic action of an acid generated by exposure is used.

The resin used for the resist for ArF excimer laser exposure does not have an aromatic ring in order to secure the transmittance of the resist, and has an alicyclic ring instead of the aromatic ring in order to have dry etching resistance. Things are known to be good. Until now, such a resin
DC Hofer, Journal of Photopolymer Science andTec
Various resins are known as described in hnology, Vol. 9, No. 3, 387-398 (1996). However, conventionally known resins have a problem in that when the polarity is insufficient, development peeling is likely to occur due to insufficient adhesiveness during development.

[0005] S. Takechi et al, Journal of Photopoly
mer Science and Technology, Vol.9, No.3, 475-487
(1996) and JP-A-9-73173 disclose methacrylic acid 2
When a polymer or copolymer of -methyl-2-adamantyl is used as a resin for a chemically amplified resist, 2-methyl-2-adamantyl is cleaved by the action of an acid to act positively, It is reported that high dry etching resistance, high resolution and good adhesion to a substrate are obtained.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a chemically amplified positive resist composition containing a resin component and an acid generator and suitable for excimer laser lithography such as ArF or KrF. Another object of the present invention is to provide a resist having excellent resist performance such as resolution and resolution, and particularly having excellent adhesiveness to a substrate.

The present inventors have previously used a resin having a butyrolactone residue in a part of polymerization units as a resin constituting a chemically amplified positive resist composition, It has been found that by using a polymer having a polymerized unit of alkyl-2-adamantyl and a polymerized unit of maleic anhydride, the adhesiveness to a substrate is improved.
A patent application has been filed as 10-191559. As a result of further research based on these findings, we found that a resin having a certain type of highly polymerized unit together with an adamantane-based polymerized unit having a specific structure is effective in improving the adhesion to substrates. Thus, the present invention has been completed.

[0008]

That is, the present invention has a polymerized unit of 2-alkyl-2-adamantyl (meth) acrylate, and further comprises 3-hydroxy-1-adamantyl (meth) acrylate and (meth) acrylate. An object of the present invention is to provide a chemically amplified positive resist composition containing a resin having a polymerized unit of a monomer selected from acrylonitrile and an acid generator.

The polymerized unit of 2-alkyl-2-adamantyl (meth) acrylate referred to herein is 2-alkyl-2-adamantyl acrylate.
In alkyl-2-adamantyl or 2-alkyl-2-adamantyl methacrylate, it means a unit formed by opening a double bond of a (meth) acrylic acid moiety, and is a unit of 3-hydroxy-1-adamantyl (meth) acrylate. The polymerized unit means a unit formed by opening a double bond of a (meth) acrylic acid portion in 3-hydroxy-1-adamantyl acrylate or 3-hydroxy-1-adamantyl methacrylate, and ) The polymerization unit of acrylonitrile means a unit formed by opening a double bond of acrylonitrile or methacrylonitrile,
They are represented by the following formulas (I) to (III), respectively.

[0010]

[0011] In the formula, R ¹ represents hydrogen or methyl, R ²
Represents alkyl.

[0012]

In the formula, R ³ represents hydrogen or methyl.

[0014]

In the formula, R ⁴ represents hydrogen or methyl.

Accordingly, this resin has essentially one or both of the unit of the above formula (II) and the unit of the above formula (III) together with the unit of the above formula (I). The resin may also have other units, for example, polymerized units of α-methacryloyloxy-γ-butyrolactone or maleic anhydride. The polymerization unit of α-methacryloyloxy-γ-butyrolactone referred to here means a unit formed by opening a double bond of a methacrylic acid portion in α-methacryloyloxy-γ-butyrolactone,
The polymerized unit of maleic anhydride means a unit formed by opening a double bond of maleic anhydride, and is represented by the following formulas (IV) and (V), respectively.

[0017]

(Meth) acrylic acid 2 of the formula (I)
Among the polymerized units of -alkyl-2-adamantyl,
Wherein R ¹ is methyl and R ² is ethyl;
That is, the polymerization unit of 2-ethyl-2-adamantyl methacrylate represented by the following formula (Ia) is important.

[0019]

The polymerized unit is a polymerized unit of 3-hydroxy-1-adamantyl (meth) acrylate represented by the formula (II), a polymerized unit of (meth) acrylonitrile represented by the formula (III), It can be used in combination with at least one of the polymerized unit of α-methacryloyloxy-γ-butyrolactone represented by (IV) and the polymerized unit of maleic anhydride represented by the formula (V). Therefore, the present invention also has a polymerized unit of 2-ethyl-2-adamantyl methacrylate, and further has 3-hydroxy-1-adamantyl (meth) acrylate, (meth) acrylonitrile, α-methacryloyloxy-γ-butyrolactone. And a resin having a polymerization unit of a monomer selected from maleic anhydride and maleic anhydride, and a chemically amplified positive resist composition containing an acid generator. This resin therefore comprises one or more of the units of the formula (II), the units of the formula (III), the units of the formula (IV) and the units of the formula (V) together with the units of the formula (Ia). Is essential.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The resin specified in the first aspect of the present invention has a polymerized unit of 2-alkyl-2-adamantyl (meth) acrylate represented by the above formula (I), It has one or both of a polymerized unit of 3-hydroxy-1-adamantyl (meth) acrylate represented by the formula (II) and a polymerized unit of (meth) acrylonitrile represented by the formula (III). Also optionally, it may have a polymerized unit of α-methacryloyloxy-γ-butyrolactone represented by the formula (IV) and / or a polymerized unit of maleic anhydride represented by the formula (V). Therefore, this resin uses 2-alkyl-2-adamantyl (meth) acrylate as one monomer, and further comprises 3-hydroxy-1- (meth) acrylate.
It can be produced by copolymerizing adamantyl and / or (meth) acrylonitrile as another monomer and, if necessary, α-methacryloyloxy-γ-butyrolactone and / or maleic anhydride as another monomer.

Among these monomers, 2-alkyl-2-adamantyl (meth) acrylate can be usually produced by reacting 2-alkyl-2-adamantanol or a metal salt thereof with acrylic acid halide or methacrylic acid halide. . 3-hydroxy-1 (meth) acrylate
-Adamantly can be produced by hydrolyzing 1,3-dibromoadamantane to 1,3-dihydroxyadamantane and reacting it with acrylic acid, methacrylic acid or a halide thereof.

(Meth) acrylic acid 2 of the formula (I)
The polymerization unit of -alkyl-2-adamantyl secures the transmittance of the resist and contributes to the improvement of dry etching resistance due to the presence of the adamantane ring which is an alicyclic ring. Further, the 2-alkyl-2-adamantyl in this unit is cleaved by the action of an acid, and thus this unit contributes to increasing the alkali solubility of the resist film after exposure. R ² in the formula (I) is an alkyl, and this alkyl can have, for example, about 1 to 8 carbon atoms, and is usually preferably straight-chain. It may be branched. Specific examples of R ² include methyl, ethyl, n-propyl, isopropyl, n-butyl and the like. Among them, those in which R ² is methyl or ethyl, particularly ethyl, are advantageous for improving the adhesion between the resist and the substrate and improving the resolution. In the formula (I), R ¹
When R is methyl and R ² is ethyl, resists containing it exhibit particularly high adhesion to substrates.

Therefore, in the present invention, the resin specified from the second aspect is a methacrylic acid 2-amino compound represented by the above formula (Ia).
It has a polymerized unit of ethyl-2-adamantyl, and further has a polymerized unit of 3-hydroxy-1-adamantyl (meth) acrylate represented by the formula (II) and a (meth) acrylonitrile represented by the formula (III). It has one or more of a polymerized unit, a polymerized unit of α-methacryloyloxy-γ-butyrolactone represented by the formula (IV) and a polymerized unit of maleic anhydride represented by the formula (V). . Therefore, this resin uses 2-ethyl-2-adamantyl methacrylate as one monomer, and further comprises 3-hydroxy-1-adamantyl (meth) acrylate, (meth) acrylonitrile, α-methacryloyloxy-γ-butyrolactone and anhydrous It can be produced by copolymerizing one or more of maleic acid as another monomer.

Of these monomers, methacrylic acid 2
-Ethyl-2-adamantyl can be produced by reacting 2-ethyl-2-adamantanol or a metal salt thereof with methacrylic halide. For example, when ethyl lithium is allowed to act on 2-adamantanone, lithium 2-ethyl-2-adamantanolate is produced. By condensing this with methacrylic acid halide, 2-ethyl-2-adamantyl methacrylate is produced. can get.

(Meth) acrylic acid 3 represented by the formula (II)
-Hydroxy-1-adamantyl polymerized unit, formula (III)
The polymerized unit of (meth) acrylonitrile represented by the formula, the polymerized unit of α-methacryloyloxy-γ-butyrolactone represented by the formula (IV), and the polymerized unit of maleic anhydride represented by the formula (V) are all polar. And the presence of any of them in the resin contributes to the improvement of the adhesiveness of the resist containing it to the substrate. Above all,
The polymerized unit of α-methacryloyloxy-γ-butyrolactone is excellent in the effect of improving adhesion, and the effect is remarkable in combination with the polymerized unit of 2-ethyl-2-adamantyl methacrylate represented by the formula (Ia). Further, even in the case of a polymerized unit of 2-alkyl-2-adamantyl (meth) acrylate represented by the formula (I), a polymerized unit of 3-hydroxy-1-adamantyl (meth) acrylate or (meth) The effect is remarkable in combination with the polymerized unit of acrylonitrile. Further, among the above units, a polymerized unit of 3-hydroxy-1-adamantyl (meth) acrylate, a polymerized unit of (meth) acrylonitrile, and a polymerized unit of maleic anhydride also contribute to improvement in dry etching resistance of the resist. And (meth) acrylic acid 3
The polymerized unit of -hydroxy-1-adamantyl and the polymerized unit of α-methacryloyloxy-γ-butyrolactone are
It also contributes to improving the resolution of the resist.

The resin for a chemically amplified positive resist is generally insoluble or hardly soluble in alkali by itself.
Some groups are cleaved by the action of an acid and become alkali-soluble after the cleaving. In the resin specified in the present invention, 2-alkyl-2-adamantyl in the formula (I) or the formula 2-Ethyl-2-adamantyl in (Ia) is cleaved by the action of an acid. Therefore, by having the polymerized unit of the formula (I) or the formula (Ia), the resist composition containing this resin acts positively.
It may contain another polymerized unit having a group that is cleaved by the action of an acid.

As other groups which are cleaved by the action of an acid, specifically, various esters of carboxylic acids, for example, tert-
Alkyl ester represented by butyl ester, methoxymethyl ester, ethoxymethyl ester, 1-ethoxyethyl ester, 1-isobutoxyethyl ester, 1-isopropoxyethyl ester, 1-ethoxypropyl ester, 1- (2-methoxyethoxy ester ) Ethyl ester, 1- (2-acetoxyethoxy) ethyl ester, 1- [2- (1-adamantyloxy) ethoxy] ethyl ester, 1- [2- (1-adamantanecarbonyloxy) ethoxy] ethyl ester, tetrahydro- Acetal type esters such as 2-furyl ester and tetrahydro-2-pyranyl ester; alicyclic esters such as isobornyl ester; The monomer leading to the polymerization unit having such a carboxylic acid ester may be an acrylic monomer such as a methacrylic acid ester or an acrylic acid ester, or a norbornene carboxylic acid ester, a tricyclodecene carboxylic acid ester, or a tetracyclodecene carboxylic acid. Like an ester, a carboxylic acid ester group bonded to an alicyclic monomer may be used.

The resin used in the present invention varies depending on the type of radiation for patterning exposure and the type of a group which can be cleaved by the action of an acid, but generally, a polymerized unit having a group which is cleaved by the action of an acid. Is preferably contained in the range of 30 to 80 mol%. Particularly, as a group which is cleaved by the action of an acid, a polymerized unit of 2-alkyl-2-adamantyl (meth) acrylate represented by the formula (I), preferably a polymerized unit of 2-ethyl-2-adamantyl methacrylate Is preferably at least 20 mol% of the whole resin. Of course, a resin having a polymerized unit of 2-ethyl-2-adamantyl methacrylate is represented by the formula (I) together with this unit,
Although it may have a polymerized unit of a monomer other than adamantyl, in this case, 2-ethyl-2-methacrylate is used.
It is preferable that the amount of the adamantyl polymerized unit be 20 mol% or more of the whole resin, and the total of the polymerized unit represented by the formula (I) including this unit is 30 to 80 mol% of the whole resin.

(Meth) acrylic acid 3 represented by the formula (II)
-Hydroxy-1-adamantyl polymerized unit, formula (III)
The polymerized unit of (meth) acrylonitrile represented by the formula, the polymerized unit of α-methacryloyloxy-γ-butyrolactone represented by the formula (IV), and the polymerized unit of maleic anhydride represented by the formula (V) are contained in the resin. 20-70 mol% in total
Is preferably present in the range. 2-alkyl-2- (meth) acrylate specified from the first aspect in the present invention
In the case of a resin having a polymerized unit of adamantyl and further having a polymerized unit of 3-hydroxy-1-adamantyl (meth) acrylate and / or a polymerized unit of (meth) acrylonitrile, 3-hydroxy (meth) acrylate- 1-
It is preferable that the total amount of the adamantyl polymer units and / or the (meth) acrylonitrile polymer units is 20 mol% or more, and optionally α-methacryloyloxy-γ.
-When a polymerization unit of butyrolactone and / or a polymerization unit of maleic anhydride is introduced, (meth) acrylic acid 3-
The total of polymerized units of hydroxy-1-adamantyl and / or polymerized units of (meth) acrylonitrile, polymerized units of α-methacryloyloxy-γ-butyrolactone and / or polymerized units of maleic anhydride is 70 mol% or less. It is preferred that Any of the resins specified from the first aspect and the second aspect may contain other polymerized units, for example, polymerized units having a free carboxylic acid group, as long as the effects of the present invention are not impaired. it can.

Another component, an acid generator, is added to the substance itself or to a resist composition containing the substance.
When a radiation such as light or an electron beam is applied, the substance is decomposed to generate an acid. The acid generated from the acid generator acts on the resin to cleave the group that is cleaved by the action of the acid present in the resin. Such acid generators include, for example, onium salt compounds, organic halogen compounds, sulfone compounds, sulfonate compounds and the like. Specifically, the following compounds can be mentioned.

Diphenyliodonium trifluoromethanesulfonate, 4-methoxyphenylphenyliodonium hexafluoroantimonate, 4-methoxyphenylphenyliodonium trifluoromethanesulfonate, bis (4-tert-butylphenyl) iodonium tetrafluoroborate, bis (4-tert
-Butylphenyl) iodonium hexafluorophosphate, bis (4-tert-butylphenyl) iodonium hexafluoroantimonate, bis (4-tert
-Butylphenyl) iodonium trifluoromethanesulfonate,

Triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium trifluoromethanesulfonate, 4-methoxyphenyldiphenylsulfonium hexafluoroantimonate, 4-methoxyphenyldiphenylsulfonium trifluoromethanesulfonate, p-tolyldiphenyl Sulfonium trifluoromethanesulfonate, p-
Tolyldiphenylsulfonium perfluorooctanesulfonate, 2,4,6-trimethylphenyldiphenylsulfonium trifluoromethanesulfonate,
4-tert-butylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-phenylthiophenyldiphenylsulfonium hexafluorophosphate, 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate, 1- (2-naphthoylmethyl) thiolanium hexafluoroantimonate, 1- (2-naphthoylmethyl) thiolanium
Trifluoromethanesulfonate, 4-hydroxy-1
-Naphthyldimethylsulfonium hexafluoroantimonate, 4-hydroxy-1-naphthyldimethylsulfonium trifluoromethanesulfonate,

2-methyl-4,6-bis (trichloromethyl) -1,3,5-triazine, 2,4,6-tris (trichloromethyl) -1,3,5-triazine, 2-
Phenyl-4,6-bis (trichloromethyl) -1,3,
5-triazine, 2- (4-chlorophenyl) -4,6
-Bis (trichloromethyl) -1,3,5-triazine, 2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4
-Methoxy-1-naphthyl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (benzo [d] [1,3] dioxolan-5-yl) -4,6-
Bis (trichloromethyl) -1,3,5-triazine,
2- (4-methoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (3
4,5-trimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (3
4-dimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (2,4-dimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5 -Triazine, 2- (2-methoxystyryl) -4,6-bis (trichloromethyl) -1,3,
5-triazine, 2- (4-butoxystyryl) -4,
6-bis (trichloromethyl) -1,3,5-triazine, 2- (4-pentyloxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,

1-benzoyl-1-phenylmethyl p
-Toluenesulfonate (commonly called benzoin tosylate), 2-benzoyl-2-hydroxy-2-phenylethyl p-toluenesulfonate (commonly called α-methylol benzoin tosylate), 1,2,3-benzenetriyl trismethanesulfonate, , 6-Dinitrobenzyl p-toluenesulfonate, 2-nitrobenzyl p-toluenesulfonate, 4-nitrobenzyl
p-toluenesulfonate,

Diphenyl disulfone, di-p-tolyl disulfone, bis (phenylsulfonyl) diazomethane, bis (4-chlorophenylsulfonyl) diazomethane, bis (p-tolylsulfonyl) diazomethane, bis (4-tert-butylphenylsulfonyl) diazomethane, Bis (2,4-xylylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane,
(Benzoyl) (phenylsulfonyl) diazomethane,

N- (phenylsulfonyloxy) succinimide, N- (trifluoromethylsulfonyloxy) succinimide, N- (trifluoromethylsulfonyloxy) phthalimide, N- (trifluoromethylsulfonyloxy) -5-norbornene-2, 3-dicarboximide, N- (trifluoromethylsulfonyloxy) naphthalimide, N- (10-camphorsulfonyloxy) naphthalimide and the like.

In general, in a chemically amplified positive resist composition, a basic compound, particularly a basic nitrogen-containing organic compound, for example, an amine is added as a quencher to thereby form an acid accompanying the withdrawal after exposure. It is known that the deterioration of performance due to deactivation can be improved. In the present invention, it is preferable to blend such a basic compound. Specific examples of the basic compound used for the quencher include those represented by the following formulas.

[0039]

In the formula, R ¹¹ , R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ independently represent hydrogen, alkyl, cycloalkyl, aryl or alkoxy which may be substituted by a hydroxyl group;
A represents alkylene, carbonyl or imino. Here, the alkyl and alkoxy represented by R ^{11 to} R ¹⁵ are
The cycloalkyl can have about 1 to 6 carbon atoms, the cycloalkyl can have about 5 to 10 carbon atoms, and the aryl can have about 6 to 10 carbon atoms. Further, the alkylene represented by A can have about 1 to 6 carbon atoms, and may be linear or branched.

The resist composition of the present invention preferably contains the resin in the range of 80 to 99.9% by weight and the acid generator in the range of 0.1 to 20% by weight based on the total solid weight. . When a basic compound is used as the quencher, the content is preferably 0.001 to 0.1% by weight based on the total solid content of the resist composition. The composition may also contain small amounts of various additives such as sensitizers, dissolution inhibitors, other resins, surfactants, stabilizers, and dyes, if necessary.

The resist composition of the present invention usually becomes a resist solution in a state where each of the above components is dissolved in a solvent, and is applied onto a substrate such as a silicon wafer. The solvent used here may be any as long as it dissolves each component, has an appropriate drying rate, and gives a uniform and smooth coating film after the solvent evaporates. A solvent generally used in this field is used. Can. For example, glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate, ethers such as diethylene glycol dimethyl ether, ethyl lactate, butyl acetate, esters such as amyl acetate and ethyl pyruvate, acetone , Methyl isobutyl ketone, ketones such as 2-heptanone and cyclohexanone, and cyclic esters such as γ-butyrolactone. These solvents can be used alone or in combination of two or more.

The resist film applied on the substrate and dried is subjected to an exposure treatment for patterning, and then to a heat treatment for accelerating the deprotection reaction, and then developed with an alkali developing solution. You. The alkaline developer used here can be various alkaline aqueous solutions used in this field, but generally, aqueous solutions of tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly known as choline) are used. Often used.

[0044]

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. Parts in the examples are by weight unless otherwise specified. The weight average molecular weight is a value determined by gel permeation chromatography using polystyrene as a standard.

Synthesis Example 1 of Monomer (Synthesis of 2-methyl-2-adamantyl methacrylate) 83.1 g of 2-methyl-2-adamantanol and 101 g of triethylamine were charged, and 200 g of methyl isobutyl ketone was added to prepare a solution. Thereto, 78.4 g of methacrylic acid chloride (1.5 mol times based on 2-methyl-2-adamantanol) was added dropwise, followed by stirring at room temperature for about 10 hours. After filtration, the organic layer was washed with a 5% by weight aqueous sodium bicarbonate solution, and then twice with water. After the organic layer was concentrated, the residue was distilled under reduced pressure to obtain 2-methyl-2-adamantyl methacrylate represented by the following formula in a yield of 75%.

[0046]

Synthesis Example 2 of Monomer (Synthesis of 2-ethyl-2-adamantyl methacrylate) 31.1 g of 2-adamantanone and 50 g of diethyl ether
Was added to the solution, and 200 ml of a diethyl ether solution containing 1.14 mol / L of ethyllithium was added dropwise thereto while maintaining the temperature of the solution not to exceed 10 ° C. After stirring at 0 ° C. for 2 hours, methacrylic acid chloride 26.2 was maintained while maintaining the temperature at not higher than 10 ° C.
g (1.2 mol times based on 2-adamantanone) was added dropwise. After completion of the dropwise addition, the mixture was stirred at room temperature for about 12 hours. afterwards,
The precipitated inorganic salt was separated by filtration, and the organic layer was washed with a 5% by weight aqueous solution of sodium bicarbonate, and then washed twice with water. After the organic layer was concentrated, the residue was distilled under reduced pressure to obtain 2-ethyl-2-adamantyl methacrylate represented by the following formula in a yield of 60%.

[0048]

Monomer Synthesis Example 3 (Synthesis of α-methacryloyloxy-γ-butyrolactone) 100 g of α-bromo-γ-butyrolactone and 104.4 g of methacrylic acid (2.0 mol times based on α-bromo-γ-butyrolactone) ) Was added, and methylisobutyl ketone (3 times by weight of α-bromo-γ-butyrolactone) was added to obtain a solution. 183.6 g of triethylamine (3.0 mol times based on α-bromo-γ-butyrolactone) was added dropwise thereto, and the mixture was stirred at room temperature for about 10 hours. After filtration, the organic layer was washed with a 5% by weight aqueous sodium bicarbonate solution, and then washed twice with water. The organic layer was concentrated to obtain α-methacryloyloxy-γ-butyrolactone represented by the following formula in a yield of 8
Obtained at 5%.

[0050]

Resin Synthesis Example 1 (Synthesis of Resin A) 2-Methyl-2-adamantyl methacrylate, 3-hydroxy-1-adamantyl methacrylate and α-methacryloyloxy-γ-butyrolactone were mixed in a ratio of 5: 2.5: 2. The mixture was charged at a molar ratio of 0.5 (20.0 g: 10.1 g: 7.8 g), and a solution was prepared by adding methyl isobutyl ketone twice the weight of all monomers. Thereto, azobisisobutyronitrile was added as an initiator in an amount of 2 mol% based on the total amount of monomers, and 85 ° C.
For about 8 hours. Thereafter, an operation of pouring the reaction solution into a large amount of heptane to precipitate was performed three times, and purification was performed. As a result, it is represented by the following formula, and the composition molar ratio of each unit is 50: 2.
At a ratio of 5:25, a copolymer having a weight average molecular weight of about 4,500 was obtained. This is designated as resin A.

[0052]

Resin Synthesis Example 2 (Synthesis of Resin B) 2-Methyl-2-adamantyl methacrylate, methacrylonitrile and maleic anhydride were mixed at a molar ratio of 5: 2.5: 2.5 (20.0 g: 3.0. 1 g: 4.5 g), and tetrahydrofuran was added in an amount of 2 times the weight of all monomers to form a solution.
Thereto, azobisisobutyronitrile was added as an initiator in an amount of 2 mol% based on the total amount of the monomers, and at 60 ° C., about 12%.
Heated for hours. Thereafter, an operation of pouring the reaction solution into a large amount of heptane and causing precipitation was performed three times to purify the reaction solution. As a result, it is represented by the following formula, and the composition molar ratio of each unit is 50:25:25.
Thus, a copolymer having a weight average molecular weight of about 8,000 was obtained. This is called resin B.

[0054]

Similarly, by copolymerizing 2-methyl-2-adamantyl methacrylate, methacrylonitrile and α-methacryloyloxy-γ-butyrolactone, a terpolymer having respective polymerized units can be obtained. .

Resin Synthesis Example 3 (Synthesis of Resin C) 2-ethyl-2-adamantyl methacrylate, 3-hydroxy-1-adamantyl methacrylate and α-methacryloyloxy-γ-butyrolactone were mixed in a ratio of 5: 2.5: 2. The same operation as in Resin Synthesis Example 1 was performed except that the mixture was charged at a molar ratio of 0.5 (20.0 g: 9.5 g: 7.3 g). As a result, a copolymer represented by the following formula and having a composition molar ratio of each unit of 50:25:25 and a weight average molecular weight of about 9,200 was obtained. This is called resin C.

[0057]

Resin Synthesis Example 4 (Synthesis of Resin D) 2-ethyl-2-adamantyl methacrylate, 3-hydroxy-1-adamantyl methacrylate and maleic anhydride were mixed at a molar ratio of 5: 2.5: 2.5 ( 20.0 g: 9.5 g:
The same operation as in Resin Synthesis Example 2 was carried out except for charging in 4.2 g). As a result, a copolymer represented by the following formula and having a composition molar ratio of each unit of 50:25:25 and a weight average molecular weight of about 17,000 was obtained. This is designated as resin D.

[0059]

Resin Synthesis Example 5 (Synthesis of Resin E) 2-Ethyl-2-adamantyl methacrylate, methacrylonitrile and maleic anhydride in a molar ratio of 5: 2.5: 2.5 (20.0 g: 2.0. 9 g: 4.2 g), except that the operation was the same as in Resin Synthesis Example 2. As a result, a copolymer represented by the following formula and having a composition molar ratio of each unit of 50:25:25 and a weight average molecular weight of about 3,400 was obtained. This is designated as resin E.

[0061]

Resin Synthesis Example 6 (Synthesis of Resin F) 2-ethyl-2-adamantyl methacrylate, methacrylonitrile, and α-methacryloyloxy-γ-butyrolactone in a molar ratio of 5: 2.5: 2.5 ( 20.0 g: 2.9 g:
7.3 g), except that the operation was the same as in Resin Synthesis Example 1. As a result, a copolymer represented by the following formula and having a composition molar ratio of each unit of 50:25:25 and a weight average molecular weight of about 6,000 was obtained. This is designated as resin F.

[0063]

Resin Synthesis Example 7 (Synthesis of Resin G) 2-Ethyl-2-adamantyl methacrylate and α-methacryloyloxy-γ-butyrolactone were charged at a molar ratio of 5: 5 (40.0 g: 29.3 g). Otherwise, the procedure was the same as in Resin Synthesis Example 1. As a result, as shown in the following formula, the composition molar ratio of each unit is 50:50, and the weight average molecular weight is about
5,600 copolymers were obtained. This is designated as resin G.

[0065]

Resin Synthesis Example 8 (Synthesis of Resin H) 2-ethyl-2-adamantyl methacrylate, 3-hydroxy-1-adamantyl methacrylate, and methacrylonitrile in a molar ratio of 5: 2.5: 2.5 ( 20.0 g: 9.5
g: 2.9 g), and tetrahydrofuran was added in an amount 2 times the weight of all monomers to form a solution. Thereto, azobisisobutyronitrile as an initiator was added at 2 mol% based on the total amount of monomers, and the mixture was heated at 65 ° C. for about 12 hours. Thereafter, an operation of pouring the reaction solution into a large amount of heptane and causing precipitation was performed three times to purify the reaction solution. As a result, a copolymer represented by the following formula and having a composition molar ratio of each unit of 50:25:25 and a weight average molecular weight of about 14,000 was obtained. This is designated as resin H.

[0067]

Resin Synthesis Example 9 (Synthesis of Resin I) 2-Ethyl-2-adamantyl methacrylate, 2-methyl-2-adamantyl methacrylate and α-methacryloxy-γ-butyrolactone were mixed at 2.5: 2.5: 5. At a molar ratio of (10.6 g: 10.0 g: 15.6 g), and methylisobutyl ketone was added at twice the weight of all monomers to form a solution. Thereto, azobisisobutyronitrile as an initiator was added at 2 mol% based on the total amount of monomers, and the mixture was heated at 85 ° C. for about 6 hours. Thereafter, an operation of pouring the reaction solution into a large amount of heptane and causing precipitation was performed three times to purify the reaction solution. As a result, it is represented by the following formula, and the composition molar ratio of each unit is 25:25:
At 50, a copolymer having a weight average molecular weight of about 9,000 was obtained.
This is called resin I.

[0069]

Resin Synthesis Example 10 (Synthesis of Resin J) 2-ethyl-2-adamantyl methacrylate, 3-hydroxy-1-adamantyl acrylate and α-methacryloyloxy-γ-butyrolactone were mixed in a ratio of 5: 2.5: 2. The mixture was charged at a molar ratio of 2.5 (20.0 g: 8.9 g: 6.8 g), and methylisobutyl ketone was added in an amount of 2 times the weight of all monomers to form a solution. Thereto, azobisisobutyronitrile as an initiator was added at 2 mol% based on the total amount of monomers, and the mixture was heated to 85 ° C. and stirred for about 5 hours. After cooling the reaction mass, an operation of pouring into a large amount of heptane and precipitating was performed three times for purification. As a result, as shown in the following formula, the composition molar ratio of each unit is 5
At a ratio of 0:25:25, a copolymer having a weight average molecular weight of about 7,500 was obtained. This is designated as resin J.

[0071]

Resin Synthesis Example 11 (Synthesis of Resin K) 2-Ethyl-2-adamantyl methacrylate and 3-hydroxy-1-adamantyl methacrylate were mixed at a molar ratio of 5: 5 (20.0 g: 19.1 g). Then, 1,4-dioxane of the same weight as the total of these monomers was added to form a solution. Thereto, azobisisobutyronitrile as an initiator was added in an amount of 3 mol% based on the total amount of monomers, and a chain transfer agent was added with 5 mol% based on the total amount of 2-ethylhexyl 3-mercaptopropionate. Was charged into a dropping funnel. Separately, 50 g of 1,4-dioxane was added to a flask kept at 70 ° C., and the above monomer solution was placed in a flask.
The mixture was added dropwise over a period of time, and then stirring was continued for about 6 hours. After cooling the reaction mass, an operation of pouring into a large amount of heptane and precipitating was performed three times for purification. As a result, a copolymer represented by the following formula and having a composition molar ratio of each unit of 50:50 and a weight average molecular weight of about 3,500 was obtained. This is referred to as resin K.

[0073]

Resin Synthesis Example 12 (Synthesis of Resin X: for comparison) 2-methyl-2-adamantyl methacrylate and α-methacryloyloxy-γ-butyrolactone were mixed at a molar ratio of 5: 5 (15.0 g: 11.7 g). ) Except that the operation was carried out in the same manner as in Resin Synthesis Example 1. As a result, as shown in the following formula, the composition molar ratio of each unit is 50:50, and the weight average molecular weight is about 1
0,000 copolymers were obtained. This is designated as resin X.

[0075]

Examples 1 and 2 10 parts of resin D or resin E (both containing maleic anhydride units) and p-tolyldiphenylsulfonium trifluoromethanesulfonate (manufactured by Midori Kagaku KK) as an acid generator 0.2 part of MDS-205 ") and 0.06 of 2,6-diisopropylaniline as quencher.
Using 15 parts thereof, these were dissolved in 45 parts of 2-heptanone, and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist solution. The resist solution prepared above was dried on a silicon wafer (contact angle of water: 50 °) treated with hexamethyldisilazane at 23 ° C. for 20 seconds or a silicon wafer coated with an organic anti-reflection film. It was applied to a thickness of 0.5 μm. The organic anti-reflection film was formed by applying “DUV-42” manufactured by Brewer to a thickness of 570 ° under a baking condition of 215 ° C. and 60 seconds. Pre-baking after applying the resist solution is performed at 120 ° C, 6
The test was performed on a direct hot plate under the condition of 0 second.

The wafer on which the resist film was formed in this manner was provided with a KrF excimer stepper [“NSR” manufactured by Nikon Corporation.
2205 EX12B ", NA = 0.55, σ = 0.8], and the line-and-space pattern was exposed by changing the exposure stepwise. The exposure of the line-and-space pattern consisted of a reticle (mask) of a dark field pattern and a bright The field pattern reticles (masks) were used, in which the dark field pattern reticles were defined as a glass pattern only in the space portion of the resist pattern and a chrome surface in all other portions. Therefore, after exposure and development, the entire periphery of the line and space pattern is given as a resist layer, and the reticle of the bright field pattern is a chrome outer frame and a glass surface inside the frame. As the line part of the resist pattern is patterned with a chrome layer, After exposure and development, the resist layer around the line-and-space pattern is removed, and a resist layer corresponding to the outer frame remains outside the pattern. After 60 seconds of post-exposure baking (PEB) at 60 ° C., paddle development was performed with a 2.38 wt% aqueous solution of tetramethylammonium hydroxide for 60 seconds, and the developed pattern was observed with a scanning electron microscope. Then, the pattern obtained from the resist film provided on the organic antireflection film substrate was examined for the effective sensitivity and resolution by the following method.

Effective Sensitivity: In the case of using a reticle of a dark field pattern and the case of using a reticle of a bright field pattern, the display was performed at an exposure amount at which a 0.3 μm line and space pattern became 1: 1.

Resolution: In the case of using the reticle of the dark field pattern and the case of using the reticle of the bright field pattern, the resolution is indicated by the minimum size of the line and space pattern separated by the exposure amount of the effective sensitivity.

The adhesiveness of the pattern on the substrate on which the organic antireflection film was not provided was evaluated. That is, the resist film formed on the substrate without the organic anti-reflection film is exposed with the effective sensitivity obtained on the organic anti-reflection film, the pattern after development is observed, and the outer frame of the bright field pattern is observed. A part of the resist remained and adhered according to the pattern of the reticle was indicated by ○, and a part of the resist in the outer frame part was peeled off and chipped was indicated by ×. The results are shown in Table 1 together with the type of resin used.

[0081]

[Table 1] 例 Example No. Resin PEB Effective sensitivity Resolution Adhesion (mJ / cm ² ) (μm ) WORK LIGHT WORK LIGHT ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example 1 D 120 ℃ 22 22 0.22 0.21 ○ 〃 2E 100 ℃ 46 44 0.19 0.18 ○ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Examples 3 to 8 and Comparative Examples 1 and 2 Ten parts of the resins shown in Table 2 (which do not contain maleic anhydride units) were used, and the solvent was 47.5 parts of propylene glycol monomethyl ether acetate. A resist solution was prepared in the same manner as in Examples 1 and 2, except that the mixed solvent was changed to 2.5 parts of γ-butyrolactone. Using these resist solutions, the procedures of Examples 1 and 2 are basically repeated, but the formation of the organic antireflection film is performed in the same manner as Examples 1 and 2 for Examples 3, 5 and 6 and Comparative Example 1. Br
"DUV-42" manufactured by Ewer Co., Ltd. was applied to a thickness of 570 ° under a baking condition of 215 ° C. and 60 seconds, and the remaining Examples 4, 7 and 8 and Comparative Example 2 were subjected to Brewer
"DUV-30-16" (manufactured by Co., Ltd.) was applied to a thickness of 1600 ° under a baking condition of 215 ° C. and 60 seconds, and PEB was carried out at a temperature shown in Table 2. Table 2 shows the obtained results together with the types of the resins used.

[0083]

[Table 2] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example No. Resin Anti-reflective coating PEB Effective sensitivity Resolution Adhesion Properties (mJ / cm ² ) (μm) WORK WORK WORK WORK WORK EXAMPLE 3 A DUV-42 120 ° C 38 36 0.24 0.21 ○ 〃 4 C DUV-30-16 120 ° C 20 20 0.22 0.21 ○ ５ 5 F DUV-42 100 ° C 42 44 0.22 0.18 ○ 〃 6 G DUV-42 80 ° C 24 24 0.20 0.20 ○ 〃 7 H DUV-30-16 120 ° C 32 30 0.21 0.19 ○ 9 8 I DUV-30-16 110 ° C 22 22 0.22 0.21 ○ ─────────────────比較 Comparative Example 1 X DUV-42 120 ° C 26 28 0.24 0.21 × 〃 2 X DUV-30-16 120 ° C 24 24 0.24 0.21 × ━━━━ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

As shown in Tables 1 and 2, a resist using the resin specified in the present invention does not cause development peeling and has excellent adhesiveness to a substrate. Further, the resolution is also good. In particular, the resists of Examples 1, 2 and 4 to 8 using a resin having a unit of 2-ethyl-2-adamantyl methacrylate have improved resolution as compared with Comparative Examples. The resist of the present invention does not significantly impair the sensitivity and has good dry etching resistance.

Examples 9 to 11 and Comparative Example 3 10 parts of the resin shown in Table 3, 0.2 part of p-tolyldiphenylsulfonium perfluorooctanesulfonate as an acid generator, and 2,6-diisopropylaniline as a quencher 0.075 parts, and these were mixed with propylene glycol monomethyl ether acetate 57.
And 3 parts of γ-butyrolactone, dissolved in a mixed solvent, and filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist solution.

"DUV-30-16", a composition for an organic anti-reflective coating manufactured by Brewer, was applied and baked at 215 ° C. for 60 seconds to form an organic anti-reflective coating having a thickness of 1,600 mm. The resist solution prepared above was spin-coated on the silicon wafer so that the film thickness after drying was 0.39 μm. After the application of the resist solution, prebaking was performed on a direct hot plate at a temperature shown in Table 3 for 60 seconds. An ArF excimer stepper [“NSR ArF” manufactured by Nikon Corporation, NA = 0.55, σ =
0.6], and the line and space pattern was exposed while changing the exposure amount stepwise. After the exposure, post-exposure baking (PEB) was performed on a hot plate at a temperature shown in Table 3 for 60 seconds, and paddle development was performed with a 2.38 wt% aqueous solution of tetramethylammonium hydroxide for 60 seconds. The bright field pattern after development was observed with a scanning electron microscope, and the effective sensitivity and resolution were examined by the following methods. The results are shown in Table 3.

Effective sensitivity: The exposure was such that a 0.18 μm line and space pattern was 1: 1.

Resolution: Displayed with the minimum size of a line and space pattern separated by the exposure amount of the effective sensitivity.

[0089]

[Table 3]

As can be seen from Table 3, when a resist using the resin specified in the present invention is applied to ArF excimer laser exposure, sensitivity and resolution are improved as compared with the comparative example. Further, the compositions used in the above Examples 1 to 8
Exposure with an rF excimer laser exposure machine gives a resist pattern with similarly excellent performance.

[0091]

Industrial Applicability The chemically amplified positive resist composition of the present invention has excellent adhesiveness to a substrate, and also has excellent resist properties such as dry etching resistance, sensitivity and resolution.
Therefore, this composition is suitable for exposure using a KrF excimer laser, an ArF excimer laser, or the like, thereby giving a high-performance resist pattern.

Claims (16)

[Claims] (1) The following formula (I) (Wherein, R ¹ represents hydrogen or methyl, and R ² represents alkyl).
A chemically amplified positive resist composition comprising a resin having a polymerized unit of a monomer selected from 3-hydroxy-1-adamantyl acrylate and (meth) acrylonitrile, and an acid generator. 2. The resin as claimed in claim 1, wherein the resin is 30 to 80 mol% of 2-alkyl-2-adamantyl (meth) acrylate and a monomer selected from 3-hydroxy-1-adamantyl (meth) acrylate and (meth) acrylonitrile. 20
The composition according to claim 1, which is obtained by copolymerization of a monomer mixture containing about 70 mol%. 3. The composition according to claim 1, wherein the resin further has a polymerized unit of a monomer selected from α-methacryloyloxy-γ-butyrolactone and maleic anhydride. 4. The resin according to claim 1, wherein said resin is a 2-alkyl-2-adamantyl (meth) acrylate in an amount of from 30 to 80 mol% and a 3-hydroxy-1-adamantyl (meth) acrylate and (meth) acrylonitrile. One monomer and a second monomer selected from α-methacryloyloxy-γ-butyrolactone and maleic anhydride in total of 2
The composition according to claim 3, which is obtained by copolymerization of a monomer mixture containing 0 to 70 mol%. 5. The polymer according to claim 1, wherein the resin is a polymerized unit represented by the formula (I):
The composition according to claim 3, which has a polymerized unit of 3-hydroxy-1-adamantyl (meth) acrylate and a polymerized unit of α-methacryloyloxy-γ-butyrolactone. 6. The composition according to claim 1, wherein R ¹ is methyl and R ² is ethyl. 7. 3-hydroxy-1- (meth) acrylate
The composition according to any one of claims 1 to 6, wherein the adamantyl is 3-hydroxy-1-adamantyl methacrylate. 8. A polymer having polymerized units of 2-ethyl-2-adamantyl methacrylate, and further comprising 3-hydroxy-1-adamantyl (meth) acrylate, (meth) acrylonitrile, α-methacryloyloxy-γ-butyrolactone and A chemically amplified positive resist composition comprising a resin having a polymerized unit of a monomer selected from maleic anhydride, and an acid generator. 9. The resin according to claim 1, wherein the resin is 2-ethyl-2-methacrylate.
Adamantyl is contained in an amount of 30 to 80 mol%, and a monomer selected from 3-hydroxy-1-adamantyl (meth) acrylate, (meth) acrylonitrile, α-methacryloyloxy-γ-butyrolactone and maleic anhydride is used.
9. The composition according to claim 8, which is obtained by copolymerization of a monomer mixture containing 0 to 70 mol%. 10. The resin according to claim 1, wherein the resin is 2-ethyl-2 methacrylate.
The composition according to claim 8, comprising a polymer unit of adamantyl and a polymer unit of 3-hydroxy-1-adamantyl (meth) acrylate. 11. The method according to claim 11, wherein the resin is 2-ethyl-2 methacrylate.
The composition according to claim 8, comprising a polymer unit of adamantyl and a polymer unit of α-methacryloyloxy-γ-butyrolactone. 12. The method according to claim 12, wherein said resin further comprises (meth) acrylic acid 3
The composition according to claim 11, having a polymerized unit of -hydroxy-1-adamantyl. 13. The resin according to claim 1, further comprising a compound of the formula (I) (Wherein, R ¹ represents hydrogen or methyl, and R ² represents alkyl) (excluding a polymerized unit of 2-ethyl-2-adamantyl methacrylate). Composition. 14. The resin according to claim 1, wherein the resin is 2-ethyl-2 methacrylate.
-20% by mole or more of adamantyl and a total of 30 to 80% by mole of 2-alkyl-2-adamantyl (meth) acrylate containing the same, and 3- (meth) acrylate
The composition according to claim 13, which is obtained by copolymerization of a monomer mixture containing 20 to 70 mol% of a monomer selected from hydroxy-1-adamantyl, (meth) acrylonitrile, α-methacryloyloxy-γ-butyrolactone and maleic anhydride. object. (15) 3-hydroxy-1 (meth) acrylate
-Adamantyl is 3-hydroxy-1-methacrylic acid;
The composition according to claim 8, 9, 10, 12, 13 or 14, which is adamantyl. 16. The composition according to claim 1, further comprising an amine as a quencher.