JPH112903A - Chemically sensitizable positive resist composition and copolymer for same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the chemically sensitizable positive resist composition adapted to an ArF or the like excimer laser lithography and good in various kinds of resist performances, such as sensitivity and resolution, and especially, to enhance adhesion to a substrate by incorporating a resin having plural kinds of specified structural units and an acid generator. SOLUTION: The positive resist composition contains the acid generator and the resin comprising the structural units each represented by formula I and formula II in which each of R<1> and R<2> is, independently, an H atom or an alkyl group optionally substituted by a hydroxy group or a hydroxy group or a -COOCH(CH3 )OC2 H4 -R<3> group or the like or each may combine with each other to form a carboxyl anhydride; R<3> is an H atom or an alkyl or -OCOR<4> group; R<4> is an alicyclic group; R<5> is an H atom or a methyl group; R<6> is an alicyclic group; X is a simple bond or a 1-4C alkylene or cyclohexylene group; and each of (m) and (n) is, independently, 0 or 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a chemically amplified positive resist composition suitably used for fine processing of semiconductors, and a copolymer useful as a resin component thereof.

[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. Such resins include DCH
ofer et al., Journal of Photopolymer Science andTe
A methacrylic ester-based resin containing an alicyclic ring, as summarized in Chnology, Vol. 9, No. 3 (1996) 387-398, is known. In addition, S. Iwasa etal., Jour
nal of Photopolymer Science and Technology, Vol. 9,
No. 3 (1996) 447-456 discloses a resin in which an alicyclic group is introduced into a group (protecting group) that is cleaved by an acid. In addition to methacrylic resin, TI
Also known are resins containing alternating copolymers of 2-norbornene and maleic anhydride, as shown in Wallow et al., Proc. SPIE 1996, 2724, 355-364. However,
Conventionally known types of resins have a sufficient amount of alicyclic ring to increase dry etching resistance, and it is difficult to obtain good resolution and sensitivity with sufficient adhesion to a substrate.

[0005]

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 performances such as sensitivity and resolution, and particularly having excellent adhesiveness to a substrate. Another object of the present invention is to provide a copolymer useful as a resin component of such a resist composition.

The present inventors have found a copolymer having a specific structural unit, and have found that by using the copolymer as a resin component of a resist composition, the adhesion to a substrate is improved. Thus, the present invention has been completed.

[0007]

That is, the present invention provides a chemically amplified positive resist composition comprising a resin having each structural unit represented by the following formulas (I) and (II) together with an acid generator. Is provided.

[0008]

In the formula, R ¹ and R ² are each independently hydrogen, alkyl which may have a hydroxyl group, a hydroxyl group or a group.
-COOCH (CH ₃ ) OC ₂ H ₄ -R ³ represents, or R ¹ and R ² together form a carboxylic anhydride residue, or a group -COOCH (CH ₃ ) OC ₂ Forming a divalent aliphatic or cycloaliphatic hydrocarbon residue optionally having H ₄ —R ³ , wherein R ³
Represents hydrogen, alkyl or —OCOR ⁴ , wherein R ⁴ represents an alicyclic group.

[0010]

In the formula, R ⁵ represents hydrogen or methyl;
⁶ represents an alicyclic group, X represents a direct bond, alkylene having 1 to 4 carbon atoms or cyclohexylene, and m and n independently represent 0 or 1.

Further, the present invention relates to the above-mentioned formulas (I) and (I)
There is also provided a copolymer having each structural unit represented by I).

The above resin or copolymer has the formula (I)
It can also have structural units other than and (II), and in particular it is advantageous to have units of the following formula (III) derived from maleic anhydride.

[0014]

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The resin constituting the positive resist composition of the present invention and the copolymer according to the present invention essentially contain the structural units represented by the above formulas (I) and (II). , Optionally further having a structural unit represented by the above formula (III).

R ¹ and R ² in the formula (I) are
Hydrogen, alkyl, alkyl having a hydroxyl group, a hydroxyl group or a group -COOCH (CH ₃ ) OC ₂ H ₄ -R ³ , wherein R ³ is hydrogen, alkyl or a group -OCOR ⁴ , wherein R ⁴ is an alicyclic group. R ¹ and R ² may together form a carboxylic anhydride residue or a divalent aliphatic or alicyclic hydrocarbon residue. When R ¹ and / or R ² is an alkyl optionally having a hydroxyl group, the number of carbon atoms can be about 1 to 4. The carboxylic anhydride residue formed by R ¹ and R ² means the following divalent group.

[0017]

When R ¹ and R ² form a divalent hydrocarbon residue, an aliphatic divalent group such as trimethylene or tetramethylene, particularly an alkylene, is formed, and R ¹ and R ² are bonded to each other. Can form a simple alicyclic ring together with the carbon atom of the above, and each carbon atom forming an alicyclic divalent group such as cyclopentane-1,3-diyl and bonding R ¹ and R ² A bridged alicyclic ring may be formed together with the atom. The portion formed by R ¹ and R ² in these alicyclic rings can have about 3 to 10 carbon atoms, preferably about 3 to 8 carbon atoms. Thus, R ¹ and R ²
And to form a divalent aliphatic or alicyclic hydrocarbon residue, the divalent aliphatic or alicyclic hydrocarbon residue has a group -COOCH (CH ₃ ) OC ₂ H ₄ -R ³ may be further combined,
Here, R ³ represents the above-mentioned meaning.

R ¹ or R ² is a group —COOCH (CH ₃ ) OC ₂ H ₄ —R ³
And R ¹ and R ² together form a divalent aliphatic or cycloaliphatic hydrocarbon residue, in which the group —COOCH (CH ₃ ) OC ₂ H
₄ If -R ³ are attached can alkyls represented by R ³ in these groups are also approximately 1 to 4 carbon atoms, R ³ is a group
Alicyclic group represented by R ⁴ in the case -OCOR is ^4, can also be a simple ring, such as cyclopentane ring and cyclohexane ring, bornane ring or norbornane ring, tricyclodecane ring, tetra It is preferably a bridged polycyclic ring such as a cyclododecane ring or an adamantane ring. Therefore, the alicyclic group represented by R ⁴ can have about 5 to 16 carbon atoms, and specifically, cyclopentyl, cyclohexyl, isobornyl, norbornyl, tricyclodecyl, tetracyclodecyl, 1-adamantyl, 2-methyl-2-adamantyl, 2-adamantyl and the like. Among them, 1-adamantyl, 2-methyl-2-
An adamantane ring such as adamantyl and 2-adamantyl, particularly 1-adamantyl is preferred.

In the structural unit represented by the formula (I), R
Those wherein ¹ and R ² are hydrogen, or a group -COOCH (CH ₃ )
Those having the formula (Ia) or (Ib) having OC ₂ H ₄ —R ³ are advantageous.

[0021]

In the formula, R ³ has the above-mentioned meaning. R ³ is
Advantageously hydrogen or bridged polycyclic cycloaliphatic carbonyloxy, especially hydrogen or 1-adamantyl carbonyloxy.

As can be seen from the above description, the structural unit of the formula (I) is 2-norbornene, a 5- and / or 6-substituted product thereof, or a compound in which the 5- and 6-positions are bonded, that is, Derived from an alicyclic unsaturated compound represented by the following formula (Ic).

[0024]

In the formula, R ¹ and R ² have the above-mentioned meanings.

Specific examples of the alicyclic unsaturated compound of the formula (Ic) include 2-norbornene, 5-norbornene-2,
3-dicarboxylic anhydride, 5-norbornene-2-methanol, 2-hydroxy-5-norbornene, tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodec-4-ene (also known as 1,2,3,4,4a, 5,8,8a-octahydro-1,4-methano-5,8-methanonaphthalene) and the above-mentioned 2- Norbornene or tetracyclo [6.
2.1.1 ^3,6 . 0 ^2,7 ] dodec-4-ene based on -COOCH (C
H ₃ ) Compounds to which OC ₂ H ₄ —R ³ (where R ³ represents the above-mentioned meaning) are bonded.

Formula (Ic) having the group -COOCH (CH ₃ ) OC ₂ H ₄ -R ³
An alicyclic unsaturated compound of the formula (I)
The monomer compound for leading to the structural unit of a) or (Ib) is represented by the following formula (Id) or (Ie).

[0028]

In the formula, R ³ has the above-mentioned meaning.

The compounds of formulas (Id) and (Ie)
For example, it can be manufactured as follows. First, R ³
Is a compound of the formula CH ₂ = CHOC ₂ H ₄
Alkyl vinyl ether corresponding to -R ³ and 2-norbornenecarboxylic acid or tetracyclo [6.2.1.1.
^3,6 . [ ^2,7 ] dodec-4-enecarboxylic acid in a suitable solvent under acidic conditions. The compound in which R ³ is a group —OCOR ⁴ is prepared by reacting an alicyclic carboxylic acid chloride corresponding to the formula R ⁴ COCl with ethylene glycol monovinyl ether in a suitable solvent under basic conditions to obtain an alicyclic carboxylic acid. Of 2-norbornenecarboxylic acid or tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] Dodeca-4
It can be produced by reacting enecarboxylic acid with an appropriate solvent under an acidic condition. As a solvent in each reaction, acetone, methyl isobutyl ketone, toluene, 1,4-dioxane, tetrahydrofuran, or the like can be used. The conditions for these reactions are as follows: normal pressure, a temperature from room temperature to about 60 ° C., 1 to 1 ° C.
It can be selected from each range of about 20 hours.

The structural unit of the formula (II) is derived from an unsaturated carboxylic acid ester compound represented by the following formula (IIa).

[0032]

In the formula, R ⁵ , R ⁶ , X, m and n have the above-mentioned meanings.

The unsaturated carboxylic acid ester compound of the formula (IIa) is a 1-cycloaliphatic carbonyloxyethyl ester of acrylic acid or methacrylic acid (when m = n = 0),
1- (ω-alicyclic carbonyloxy alkoxy) ethyl ester (when m = 1, n = 0), 1- (1-alicyclic carbonyloxy ethoxy) ethyl ester (m = 0, n =
1) or 1- [ω- (1-alicyclic carbonyloxyethoxy) alkoxy] ethyl ester (m = n = 1
Case). Therefore, this unsaturated carboxylic acid ester compound can be prepared according to the case where m = n = 0, the case where m = 1 and n = 0, the case where m = 0 and n = 1, and the case where m = n = 1. The following formulas (IIb), (IIc), (IId) or (I
Ie).

[0035]

In the formula, R ⁵ , R ⁶ and X have the same meaning as described above.

Formulas (II), (IIa), (IIb), (IIc), (II
In d) and (IIe), the alicyclic group represented by R ⁶ is obtained by removing a carboxyl group from an alicyclic carboxylic acid, and may have about 5 to 16 carbon atoms. The type is not particularly limited, but a crosslinked polycyclic one is particularly preferable. Specific examples include a bornane ring, a norbornane ring, a tricyclodecane ring, a tetracyclododecane ring, an adamantane ring, and more specifically, isobornyl, norbornyl, tricyclodecyl,
Tetracyclodecyl, 1-adamantyl, 2-methyl-
2-adamantyl, 2-adamantyl and the like. Among them, an adamantane ring such as 1-adamantyl, 2-methyl-2-adamantyl and 2-adamantyl, particularly 1-adamantyl is preferable. X is
It is a direct bond, alkylene having 1 to 4 carbon atoms or cyclohexylene, and the position of the bond of cyclohexylene is arbitrary. Those in which X is a direct bond are advantageous as raw materials.

The compound of the formula (IIb) is, for example, of the formula R ⁶ COOH
Can be produced by reacting an alicyclic carboxylic acid corresponding to the above with a vinyl ester and then reacting it with acrylic acid or methacrylic acid in a suitable solvent under acidic conditions. The formula (I
The compound of the formula Ic) can be obtained, for example, by reacting an alicyclic carboxylic acid chloride corresponding to the formula R ⁶ COCl with an alkylene glycol monovinyl ether in a suitable solvent under basic conditions to give a vinyloxyalkyl of an alicyclic carboxylic acid. The ester can be produced by reacting it with acrylic acid or methacrylic acid in an appropriate solvent under acidic conditions. Further, the compounds of the formulas (IId) and (IIe) are each, for example, a divinyl ether or an alkylene glycol divinyl ether corresponding to the formula CH ₂ = CH (OCH ₂ -X-CH ₂ ) _m OCH = CH ₂ It can be prepared by reacting acrylic acid or methacrylic acid and an alicyclic carboxylic acid corresponding to the formula R ⁶ COOH in a solvent in any order under acidic conditions. As a solvent in each reaction, acetone, methyl isobutyl ketone, toluene, 1,4-dioxane, tetrahydrofuran, or the like can be used. Conditions for these reactions can be selected from a range of around normal pressure, a temperature from room temperature to about 60 ° C., and a time of about 1 to 20 hours.

The unsaturated carboxylic acid ester compounds of the formula (IIa), ie, the compounds of the formulas (IIb), (IIc), (IId) and (IIe)
Specifically, for example, the following compounds can be mentioned.

1-methacryloyloxyethyl 2-norbornanecarboxylate, tetracyclo [6.2.1.
^13-6 . 0 ^2,7 ] 1-methacryloyloxyethyl dodecane-4-carboxylate, 1-methacryloyloxyethyl 1-adamantanecarboxylate, 2- (1-methacryloyloxyethoxy) ethyl 2-norbornanecarboxylate, tetracyclo [6 2.2.1.1 ^3,6 . 0 ^2,7 ] dodecane-4-carboxylate 2- (1-methacryloyloxyethoxy) ethyl, 1-adamantanecarboxylate 2- (1-methacryloyloxyethoxy) ethyl, 2-methyl-2-adamantanecarboxylate 2 -(1-methacryloyloxyethoxy) ethyl, 2- (1-methacryloyloxyethoxy) ethyl 2-adamantanecarboxylate, 1- (1-methacryloyloxyethoxy) ethyl 1-adamantanecarboxylate, 1-adamantanecarboxylic acid 1- [2- (1-methacryloyloxyethoxy) ethoxy] ethyl, 1- [4- (1-methacryloyloxyethoxy) butoxy] ethyl 1-adamantanecarboxylate, 1- [4- (1-adamantanecarboxylate) 1-methacryloyloxyethoxymethyl) cyclohexylmethoxy] ethyl and the like.

2-norbornene or a derivative thereof as a unit of the formula (I), an unsaturated carboxylic acid ester compound of the formula (IIa) as a unit of the formula (II), and optionally an anhydride of a unit of the formula (III) The copolymerization using maleic acid can be carried out by dissolving each monomer in an appropriate solvent at a predetermined ratio, and by a usual solution polymerization method. Examples of the solvent include methyl isobutyl ketone, tetrahydrofuran,
1,4-dioxane and the like can be mentioned. This reaction is usually performed in the presence of a polymerization initiator such as azobisisobutyronitrile or benzoyl peroxide at a temperature of about 50 to 100 ° C. for about 1 to 10 hours.

The copolymer or resin according to the present invention essentially contains the structural units represented by the formulas (I) and (II), and the proportion of each is based on the formula (I) based on the entire copolymer. The structural unit of the formula (II) is preferably about 10 to 70 mol%, and the structural unit of the formula (II) is preferably about 30 to 90 mol%. When the structural unit of the formula (III) is introduced as the third component, its amount is preferably about 35 mol% or less based on the whole copolymer. In particular, when the copolymer has the structural unit of the formula (III), the structural unit of the formula (I) is about 10 to 35 mol% and the structural unit of the formula (II) is about 30 mol% based on the whole copolymer.
About 80 mol%, and the structural unit of the formula (III) is
It is preferably about 35 mol%. In addition, other structural units may be provided as long as the effects of the present invention are not impaired. However, each of the structural units of the formulas (I), (II) and (III) is a total based on the entire copolymer. It is preferably at least 70 mol%. The weight average molecular weight of the copolymer or resin is preferably about 4,000 to 30,000.

The copolymer or resin containing the structural units of the formulas (I) and (II) and optionally the structural unit of the formula (III) according to the present invention is insoluble or hardly soluble in alkali by itself. there is, by the action of an acid cleaved in structural units of formula (II), also structural units groups -COOCH (CH ₃₎ of formula (I) OC
_{When it has 2} H ₄ —R ³ , it is cleaved even in the group, and becomes alkali-soluble after cleaving. Therefore, the resist composition of the present invention contains an acid generator in addition to the above resin. The acid generator is a substance that is decomposed to generate an acid by causing radiation such as light or an electron beam to act on the substance itself or a resist composition containing the substance. The acid generated from the acid generator acts on the resin to cleave the easily cleavable group (protecting group) 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 exemplified.

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, 2,
4,6-trimethylphenyldiphenylsulfonium
Trifluoromethanesulfonate, 4-tert-butylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-phenylthiophenyldiphenylsulfonium hexafluorophosphate, 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate, 1- (2-naphthoylmethyl) thiolanium hexa Fluoroantimonate, 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, so that the acid accompanying withdrawal after exposure is exposed. 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.

[0051]

Wherein R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵
Each independently represents hydrogen, alkyl, cycloalkyl, aryl or alkoxy which may be substituted by a hydroxyl group, and A represents alkylene, carbonyl or imino.
Here, the alkyl and alkoxy represented by R ²¹ to R ²⁵ can have about 1 to 6 carbon atoms, the cycloalkyl can have about 5 to 10 carbon atoms, and the aryl has The number can be on the order of 6-10. 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 weight of the total solid content. . When a basic compound is used as the quencher, the content is preferably 0.001 to 1% by weight based on the total solid weight 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 solvent that dissolves the respective components, has an appropriate drying rate, and gives a uniform and smooth coating film after the solvent is evaporated, and is commonly used in this field. be able to. For example, glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate, esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate, acetone, methyl isobutyl ketone, 2-heptanone And ketones such as 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, tetramethylammonium hydroxide or (2-hydroxyethyl) trimethylammonium hydroxide (commonly known as choline) is used. Aqueous solutions are often used.

[0056]

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.

Synthesis Example 1 (Synthesis of Monomer) 55.1 g of 1-adamantane carbonyl chloride and 44 g of pyridine were charged, and methylisobutyl ketone was added by 2 times the weight of 1-adamantane carbonyl chloride to form a solution. There ethylene glycol monovinyl ether 3
7.2 g (1.5 mol times based on 1-adamantane carbonyl chloride) was added dropwise, 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 solution of sodium bicarbonate, and then washed twice with water. After concentrating the organic layer, 3 weight times 1,4-dioxane was added to form a solution,
An appropriate amount of p-toluenesulfonic acid monohydrate and 36 g of methacrylic acid were charged therein and stirred at room temperature for about 10 hours. Thereafter, the organic layer was washed with a 5% by weight aqueous solution of sodium bicarbonate, and then washed twice with water. The organic layer was concentrated to obtain 2- (1-methacryloyloxyethoxy) ethyl 1-adamantanecarboxylate represented by the following formula.

[0058]

Synthesis Example 2 (Synthesis of Resin A1) 2-norbornene, maleic anhydride and 2- (1-methacryloyloxyethoxy) ethyl 1-adamantanecarboxylate obtained in Synthesis Example 1 were mixed with 3: 3: 4 (18.8 g: 19.6 g: 89.9 g), and a solution was prepared by adding methyl isobutyl ketone twice the weight of all monomers. Thereto, azobisisobutyronitrile as an initiator was added at 2 mol% based on the total amount of monomers, and the mixture was heated at 80 ° C. for about 8 hours. Thereafter, an operation of pouring the reaction solution into a large amount of heptane to cause precipitation was performed twice, and purification was performed. as a result,
It is represented by the following formula, and the composition molar ratio of each unit is 30:30:40.
Thus, a copolymer having a weight average molecular weight of about 10,000 was obtained.

[0060]

Synthesis Example 3 (Synthesis of Resin A2) In Synthesis Example 2, the molar ratio of 2-norbornene, maleic anhydride and 2- (1-methacryloyloxyethoxy) ethyl 1-adamantanecarboxylate was 2: 2: 6.
Synthesis Example 2 except that (3.7 g: 3.9 g: 40.0 g) was used.
The same operation as described above was performed. As a result, a copolymer represented by the following formula and having a composition molar ratio of each unit of 20:20:60 and a weight average molecular weight of about 10,000 was obtained.

[0062]

Synthesis Example 4 (Synthesis of Monomer) 90.8 g of 5-norbornene-2-carboxylic acid obtained from cyclopentadiene and acrylic acid and 130 g of dicyclopentadiene were charged and reacted at 150 ° C. for 10 hours. Extracted at pH 10 using aqueous solution. To the aqueous layer was added 100 cc of diethyl ether, extracted with hydrochloric acid at pH 2.0, and the ether layer was washed with water and concentrated under reduced pressure to obtain tetracyclo [6.2.1.1 ^{3,6 represented} by the following formula. . [0 ^2,7 ] dodec-4-enecarboxylic acid was obtained in a yield of 27.2%.

[0064]

The tetracyclo [6.2.1.
^13-6 . [0 ^2,7 ] dodeca-4-enecarboxylic acid (34.5 g) was dissolved in 1,4-dioxane (100 g), and p-toluenesulfonic acid (0.1 g) and ethyl vinyl ether (25.0 g) were dissolved therein.
After reacting at room temperature for 2 hours, the organic layer was extracted with water and further concentrated to obtain tetracyclo [6.2.1.1 ^3,6 . [0 ^2,7 ] 1-ethoxyethyl dodeca-4-enecarboxylate was obtained in a yield of 85.0%.

[0066]

Synthesis Example 5 (Synthesis of Resin A3) Tetracyclo [6.2.1.
^13-6 . [0 ^2,7 ] 1-ethoxyethyl dodeca-4-enecarboxylate, maleic anhydride and 2- (1-methacryloyloxyethoxy) ethyl 1-adamantanecarboxylate obtained in the same manner as in Synthesis Example 1. : 2: 6 molar ratio (10.9 g: 3.9 g: 40.0 g), and tetrahydrofuran 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 at 63 ° C. for about 12 hours. Thereafter, an operation of pouring the reaction solution into a large amount of heptane to cause precipitation was performed twice, and purification was performed. As a result, it is represented by the following formula, and the composition molar ratio of each unit is 20:20:60.
Thus, a copolymer having a weight average molecular weight of about 10,000 was obtained.

[0068]

Synthesis Example 6 (Synthesis of Monomer) 1-adamantanecarbonyl chloride and ethylene glycol monovinyl ether were reacted in the same manner as in the first half of Synthesis Example 1. Next, the reaction solution was extracted with toluene, the organic layer was washed with an aqueous sodium bicarbonate solution, washed with water, and then the organic layer was concentrated to obtain 2-vinyloxyethyl 1-adamantanecarboxylate represented by the following formula.

[0070]

5-norbornene-2-carboxylic acid 35.8
8 g and the 1-adamantanecarboxylic acid 2 obtained above
50.0 g of vinyloxyethyl was charged, and 150 g of 1,4-dioxane was added to form a solution. Thereto was added 0.1 g of p-toluenesulfonic acid, and the mixture was stirred at 50 ° C for 5 hours.
After cooling to room temperature, washing with an aqueous potassium carbonate solution and washing with water were performed. The organic layer is concentrated under reduced pressure to give 5-norbornene-2-carboxylic acid 1- [2
-(1-Adamantylcarbonyloxy) ethoxy] ethyl was obtained.

[0072]

Synthesis Example 7 (Synthesis of Resin A4) 1- [2- (1-Adamantylcarbonyloxy) ethoxy] ethyl 5-norbornene-2-carboxylate obtained in Synthesis Example 6, maleic anhydride and Synthesis Example 2- (1-methacryloyloxyethoxy) ethyl 1-adamantanecarboxylate obtained in the same manner as in Example 1 was charged in a molar ratio of 3: 3: 4 (34.6 g: 8.7 g: 40.0 g), A solution was prepared by adding tetrahydrofuran twice the weight of all monomers.
Thereto, azobisisobutyronitrile as an initiator was added at 2 mol% based on the total amount of monomers, and the mixture was heated at 63 ° C. for about 12 hours. Thereafter, an operation of pouring the reaction solution into a large amount of heptane to cause precipitation was performed twice, and purification was performed. As a result, it is represented by the following formula, and the composition molar ratio of each unit is 30:30:40,
A copolymer having a weight average molecular weight of about 10,000 was obtained.

[0074]

Synthesis Example 8 (Synthesis of Resin A5) 2-norbornene and 2- (1-methacryloyloxyethoxy) ethyl 1-adamantanecarboxylate obtained in the same manner as in Synthesis Example 1 were in a molar ratio of 4: 6 ( 7.5g: 4
0.0g), and tetrahydrofuran 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 at 63 ° C. for about 12 hours. Thereafter, an operation of pouring the reaction solution into a large amount of heptane to cause precipitation was performed twice, and purification was performed. As a result, a copolymer represented by the following formula and having a composition molar ratio of each unit of 40:60 and a weight average molecular weight of about 10,000 was obtained.

[0076]

Synthesis Example 9 (Synthesis of monomer) 86 g of ethylene glycol divinyl ether and 0.1 g of p-toluenesulfonic acid were charged, and 1,4-dioxane 1
50 g was added to make a solution. 43 g of methacrylic acid there
Was added dropwise over 1 hour, and the mixture was further stirred at room temperature for 2 hours.
Next, toluene was added, the toluene was washed with an aqueous sodium bicarbonate solution and water, and the toluene layer was concentrated. By distilling the concentrated residue under reduced pressure, methacrylic acid 1-
(2-Vinyloxyethoxy) ethyl was obtained in a yield of 55%.

65 g of 1- (2-vinyloxyethoxy) ethyl methacrylate obtained above, 70 g of 1-adamantanecarboxylic acid and 0.1 g of p-toluenesulfonic acid were charged, and 100 g of 1,4-dioxane was added thereto. And After stirring at room temperature for 2 hours, toluene was added, the toluene was washed with an aqueous sodium bicarbonate solution and water, and then the toluene layer was concentrated. The concentrated residue was further distilled under reduced pressure to give 1-adamantanecarboxylic acid 1- [2-
(1-methacryloyloxyethoxy) ethoxy] ethyl was obtained in a yield of 85%.

[0079]

Synthesis Example 10 (Synthesis of Resin A6) 2-norbornene, maleic anhydride and 1- [2- (1-methacryloyloxyethoxy) ethoxy] ethyl 1-adamantanecarboxylate obtained in Synthesis Example 9 were 3:
Charged at a molar ratio of 3: 4 (5.0 g: 5.1 g: 26.7 g), 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 monomers, and 6
The temperature was raised to 0 ° C. and reacted for 12 hours. After cooling to room temperature, the operation of pouring the reaction solution into a large amount of heptane and precipitating was performed twice to purify. As a result, as shown in the following formula, the composition molar ratio of each unit is 30:30:40, and the weight average molecular weight is about 10,
000 copolymers were obtained.

[0081]

Synthesis Example 11 (Synthesis of resin AX: for comparison) 8- (1-methacryloyloxyethoxy) ethyl 1-adamantanecarboxylate and methacrylic acid in a molar ratio of 8: 2 (33.7 g: 2.2 g) Except for the preparation, operations were carried out according to Synthesis Example 2. As a result, a copolymer represented by the following formula and having a composition molar ratio of each unit of 80:20 and a weight average molecular weight of about 10,000 was obtained.

[0083]

Examples 1 to 7 In each case, 15 parts of the resin shown in Table 1 and 0.3 part of α-methylol benzoin tosylate (manufactured by Midori Kagaku Co., Ltd.) as an acid generator are shown in Table 1. Using 0.02 parts of the indicated quencher, dissolving them in 60 parts of propylene glycol monomethyl ether acetate, and further adding 0.2 parts of pore diameter
The solution was filtered through a μm fluororesin filter to prepare a resist solution. Hexamethyldisilazane (HMDS)
Silicon wafer (water contact angle 60 °) treated with
Coating was performed so that the film thickness after drying was 0.72 μm. Prebaking after the application of the resist solution was performed on a direct hot plate at 130 ° C. for 60 seconds.

The wafer on which the resist film was formed in this manner was coated with a KrF excimer stepper [“NSR-
The line and space pattern was exposed using 1755 EX8A ", NA = 0.45].
Post-exposure bake at 0 ° C for 60 seconds (P
EB) and paddle development with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 60 seconds. The pattern after development was observed with a scanning electron microscope, and the sensitivity, resolution, and adhesion were examined by the following methods. Table 1 shows the results together with the resist composition.

Sensitivity: The exposure amount (effective sensitivity) at which the 0.5 μm line and space pattern becomes 1: 1 was displayed.

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

Adhesion: The pattern after exposure and development with an exposure amount of 0.5: 1 line-and-space pattern of 1: 1 was adhered to the substrate, and the pattern was slightly peeled off. Was determined to be ×.

[0089]

[Table 1]

(Footnote to Table 1) Quencher C1: 2,2'-dipyridylamine C2: 2,6-diisopropylaniline

As shown in Table 1, according to the present invention, resists using resins A1 to A6, which are binary or ternary copolymers of specific components, do not peel off during development and have excellent adhesion to substrates. ing. Also, the resolution and sensitivity are excellent. The composition used in Examples 1 to 7 was ArF
Exposure with an excimer laser exposure machine also gives a resist pattern with excellent performance.

Comparative Example When the same operation as in Examples 1 and 2 was performed except that the resin AX obtained in Synthesis Example 11 was used instead of the resin A1, the pattern after development was peeled off from the substrate and fell. As a result, sensitivity and resolution could not be measured.

[0093]

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 sensitivity and resolution. In addition, this resist composition has a high hydrophilicity and a good wettability to an alkali developing solution, and thus has a good profile (pattern shape).
give. Therefore, this composition is suitable for exposure using a KrF excimer laser, an ArF excimer laser, or the like, whereby a high-performance resist pattern can be obtained. Further, the copolymer according to the present invention is useful as a resin component of the resist composition.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/027 H01L 21/30 502R

Claims (15)

[Claims] (1) The following formulas (I) and (II) [Wherein, R ¹ and R ² are each independently hydrogen, an alkyl optionally having a hydroxyl group, a hydroxyl group or a group -COOCH (CH
₃ ) represents OC ₂ H ₄ —R ³ or whether R ¹ and R ² together form a carboxylic anhydride residue represented by —C (= O) OC (= O) — , or a group _{-COOCH (CH 3) OC 2 H} 4 -R 3 2 valent may have the form an aliphatic or alicyclic hydrocarbon residues, wherein, R ³ is hydrogen, alkyl or - OCOR ⁴ wherein R ⁴ represents an alicyclic group] [Wherein, R ⁵ represents hydrogen or methyl, R ⁶ represents an alicyclic group, X represents a direct bond, alkylene having 1 to 4 carbon atoms or cyclohexylene, and m and n each independently represent 0. Or a compound having the structural unit represented by formula (1), and an acid generator. 2. The resin further comprises a compound of the formula (III) The composition according to claim 1, which has a structural unit represented by the formula: (3) R ¹ and R ² in the formula (I) are each independently hydrogen, alkyl optionally having a hydroxyl group, or a hydroxyl group, or R ¹ and R ² are Forming a divalent aliphatic or alicyclic hydrocarbon residue, or forming a carboxylic anhydride residue represented by -C (= O) OC (= O)-; 3. The composition according to claim 2, wherein X is a direct bond, m is 0 or 1, and n is 0. (4) the structural unit of the formula (I) is represented by the formula (Ia) or (Ib): Wherein R ³ represents hydrogen, alkyl or —OCOR ⁴ ;
Here, R ⁴ represents an alicyclic group]. 5. The composition according to claim 1, further comprising a basic nitrogen-containing organic compound as a quencher. 6. The following formulas (I) and (II) [Wherein, R ¹ and R ² are each independently hydrogen, an alkyl optionally having a hydroxyl group, a hydroxyl group or a group -COOCH (CH
₃ ) represents OC ₂ H ₄ —R ³ or whether R ¹ and R ² together form a carboxylic anhydride residue represented by —C (= O) OC (= O) — , or a group _{-COOCH (CH 3) OC 2 H} 4 -R 3 2 valent may have the form an aliphatic or alicyclic hydrocarbon residues, wherein, R ³ is hydrogen, alkyl or - OCOR ⁴ wherein R ⁴ represents an alicyclic group] [Wherein, R ⁵ represents hydrogen or methyl, R ⁶ represents an alicyclic group, X represents a direct bond, alkylene having 1 to 4 carbon atoms or cyclohexylene, and m and n each independently represent 0. Or represents 1]. 7. The copolymer according to claim 6, wherein R ¹ and R ² in the formula (I) are hydrogen. 8. The compound represented by the formula (I) is a compound represented by the formula (Ia) or (Ib): Wherein R ³ represents hydrogen, alkyl or —OCOR ⁴ ;
Here, R ⁴ represents an alicyclic group]. 9. The copolymer according to claim 8, wherein R ^{3 in} formulas (Ia) and (Ib) is hydrogen or 1-adamantyl carbonyloxy. 10. The copolymer according to claim 6, wherein m and n in the formula (II) are both 0. 11. The copolymer according to claim 6, wherein X in the formula (II) is a direct bond, m is 1, and n is 0. 12. The copolymer according to claim 6, wherein m in the formula (II) is 0 and n is 1. 13. The copolymer according to claim 6, wherein m and n in the formula (II) are both 1. 14. The copolymer according to claim ⁶ , wherein R ⁶ in the formula (II) is 1-adamantyl. 15. A compound of the formula (III) The copolymer according to any one of claims 6 to 14, which has a structural unit represented by: