JP2000250220A - Radiation sensitive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a radiation sensitive composition having low edge roughness, a large depth of a focus and high resolution adaptable to quarter-micron lithography by using a resin containing a specified structure as a constituent component. SOLUTION: The radiation sensitive composition contains a resin obtained by protecting part of phenolic hydroxyl groups in the same molecular chain of an alkali-soluble resin having phenolic hydroxyl groups with two or more mutually different protective groups and a photo-acid generating agent. Groups of formulae I and II are contained as the protective groups and the protection rate (Pa mol%) with the groups of the formula I is higher than the protection rate (Pb mol%) with the groups of the formula II. In the formula I, R1 and R2 are each H or optionally substituted 1-6C alkyl, R1 and R2 may bond to each other to form a ring, R3 is 1-12C optionally substituted alkyl and R2 and R3 may bond to each other to form a ring. In the formula II, R4 is 1-3C alkyl or alkoxy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a radiation-sensitive composition sensitive to radiation, and more particularly to a radiation-sensitive composition suitable as a resist for forming a lithographic printing plate or a semiconductor integrated circuit. In particular, wavelength 2
The present invention relates to a radiation-sensitive composition suitable for deep ultraviolet exposure of 00 to 300 nm.

[0002]

2. Description of the Related Art As the degree of integration of semiconductor integrated circuits increases, for example, dynamic random access memories (D
Taking RAM as an example, full-scale production of a memory having a storage capacity of 64 Mbits has been started. Photolithography is essential for integrated circuit production
The demands on technology are increasing year after year. For example, the production of a 64 Mbit DRAM requires a lithography technique of a 0.25 μm level, and a 256 M DRAM with a higher degree of integration requires a lithography technique of a level of 0.20 μm or less. Along with this, development of a resist that can correspond to each lithography level has been eagerly desired.

Lithography below the 0.25 μm level
It has become necessary to use a KrF excimer laser light (248 nm) or ArF excimer laser light (193 nm) light source shorter than the wavelength of the i-line (365 nm) of the conventionally used mercury lamp. As a positive resist suitable for such short-wavelength exposure, various chemically amplified positive photoresists suitable for high sensitivity have been proposed. The chemically amplified resist controls the solubility of a radiation-irradiated portion in a developing solution by a catalytic action of an acid generated by irradiation of radiation (ultraviolet rays, far-ultraviolet rays, X-rays, charged particle beams such as electron beams, etc.). It is a resist and contains a compound that increases the solubility in an alkali developer by an acid-catalyzed reaction with a photoacid generator, and high sensitivity can be realized by this acid-catalyzed reaction.

[0004] For example, Japanese Patent Application Laid-Open Nos.
No.-48826 discloses that by mixing polyhydroxystyrene having an acetal-type protecting group such as an ethoxyethyl group and polyhydroxystyrene having a carbonate-type protecting group such as a t-butoxycarbonyloxy group,
A resist excellent in heat resistance and the like is disclosed. Specifically, Japanese Patent Application Laid-Open No. 8-15864 describes that when polyvinylphenol having an ethoxyethyl group and polyvinylphenol having a t-butyloxycarbonyloxy group are combined, heat resistance is improved. or,
Japanese Patent Application Laid-Open No. 10-48826 also discloses that a high-resolution pattern can be formed by using resins having different protecting groups in combination, and examples of variously changing acetal type and carbonate type protecting groups are shown. In addition, while an example of using a copolymer type resin in which a resin used in combination has different protecting groups in the molecular chain is shown, it is said that the pattern shape is insufficient when the copolymer type resin alone is used.

According to the study of the present inventors, it has been found that these materials have a rough surface or side surface of a resist pattern and an insufficient depth of focus. When the surface or side surface of the resist pattern is rough, that is, when the so-called edge roughness is large, it causes scum, and the etching performed after the formation of the resist pattern is not uniform, so that etching as designed becomes difficult.

On the other hand, JP-A-9-31452 discloses a copolymer type polyvinylphenol having an acetal-type protecting group such as an ethoxyethyl group and a t-butyloxycarbonyloxy group in the same molecular chain.
It is shown that the balance of characteristics such as resolution, pattern shape and heat resistance is good, but as a result of examination, as the depth of focus shifts from the optimal focus, the T-top shape and undercut become remarkable, It was found that the required resist performance was insufficient.

[0007] Depth of focus
s: hereinafter abbreviated as DOF) means a margin from an optimum focal length when forming a resist pattern on a wafer, and refers to a range in which there is no problem compared to a transferred image at an optimum focus. In the manufacture of LSI, the wafer may be uneven or warped on the wafer substrate, or the wafer may bend or deform due to various processes such as high-temperature processing. In some cases, the pattern shape significantly deteriorates, and a wide DOF is required to increase the yield of semiconductor manufacturing.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to reduce edge roughness,
An object of the present invention is to provide a radiation-sensitive composition having a wide depth of focus and a high resolution capable of supporting quarter-micron lithography. In particular, it is an object of the present invention to provide a radiation-sensitive composition in which the pattern shape hardly becomes a shape such as T-top or undercut even when defocused.

[0009]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that, as a resin, at least a part of the phenolic hydroxyl group of an alkali-soluble resin having a phenolic hydroxyl group is protected by a different protecting group, and an acetal type structure is obtained. And a copolymer type resin having a carbonate type structure, wherein the number of carbon atoms in the protective group of the carbonate type structure is small, and the proportion of the acetal type structure is larger than the proportion of the carbonate type structure, We have found that the above objective is achieved.

That is, the gist of the present invention is to provide an alkali-soluble resin having a phenolic hydroxyl group, wherein at least a part of the phenolic hydroxyl group in the same molecular chain is protected by two or more different protecting groups. And a radiation-sensitive composition containing a photoacid generator (b), wherein the resin (a) contains a group represented by the following general formula (1) and a group represented by the following general formula (2) as a protective group, and Protection ratio (Pa) by the group of the general formula (1)
(Mol%) is larger than the protection ratio (Pb mol%) by the group of the general formula (2).

[0011]

Embedded image

(Where R₁And R_TwoAre hydrogen sources
C or an optionally substituted C₁~ C ₆The alkyl group of
And R₁And R_TwoMay combine to form a ring. R_Three
Is C₁~ C₁₂Is an optionally substituted alkyl group
R_TwoAnd R_ThreeMay combine to form a ring. R_FourIs
C₁~ C_ThreeRepresents an alkyl group or an alkoxy group. )
Exists.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
In the resin (a) of the present invention, at least a part of the phenolic hydroxyl group in the same molecular chain of an alkali-soluble resin having a phenolic hydroxyl group (hereinafter, sometimes referred to as a base resin) is represented by the general formula (1). It is a resin having a structure protected by a protecting group and a protecting group represented by the general formula (2). That is, it has a structure in which the groups represented by general formulas (1) and (2) are respectively bonded to the oxygen atom of the phenolic hydroxyl group.

The alkali-soluble resin having a phenolic hydroxyl group is a novolak resin or polyvinylphenol or a derivative thereof. Considering the wavelength of a KrF excimer laser already used in the manufacture of semiconductors, polyvinylphenol or a derivative thereof having a low absorbance at that wavelength is preferred. Derivatives of polyvinyl phenol include, for example, resins obtained by polymerization of hydroxystyrenes alone or copolymerization of hydroxystyrene with various vinyl monomers. As vinyl monomers copolymerized with hydroxystyrene, styrene,
Acrylic acid, vinyl alcohol or derivatives thereof are used.

As the polyvinylphenol and its derivatives, specifically, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (o-hydroxyphenyl) propylene, 2- (m-hydroxyphenyl) A) A resin obtained by polymerizing one or more hydroxystyrenes such as propylene and 2- (p-hydroxyphenyl) propylene in the presence of a radical polymerization initiator, an anionic polymerization initiator or a cationic polymerization initiator is used. Further, a resin which has been subjected to hydrogenation in order to reduce the absorbance of the resin after polymerization may be used, or a halogen atom, a nitro group, an ester group, or the like in the aromatic compound monomer as long as it does not adversely affect the present invention. It may have a substituent.

The hydroxy aromatic compound may have a substituent such as a halogen atom, a nitro group or an ester group as long as it does not adversely affect the present invention. If necessary, these resins may be further reduced with hydrogen or the like to reduce the absorbance in the short wavelength region. The weight average molecular weight of the base resin is usually from 1,000 to 50,000 in terms of polystyrene by gel permeation chromatography (GPC), and preferably from 2,000 to 30,000 in terms of coating properties.

In the present invention, at least a part of the phenolic hydroxyl group in the same molecular chain of the base resin as described above is protected, and is protected by the protecting group of the above formula (1) and the protecting group of the above formula (2). Must contain protected resin. That is, it is necessary to include a copolymer type resin having a structural unit derived from hydroxystyrene having a protective group represented by the formula (1) and a structural unit derived from hydroxystyrene having a protective group represented by the formula (2). .

The protecting group represented by the formula (1) may be present alone in the same molecular chain may coexist different groups from each other represented by the formula (1), wherein, R ₁ and R ₂ is independently a hydrogen atom or an optionally substituted C ₁ -C
_And R ₁ and R ₂ may combine to form a ring. R ₃ is a C _{1 to} C ₁₂ optionally substituted alkyl group, and R ₂ and R ₃ may combine to form a ring.

R ₁ and R ₂ are each independently preferably a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, and R ₃ is preferably an alkyl group having 1 to 1 carbon atoms.
An alkyl group of 0 is preferred. Incidentally, the alkyl group is a straight-chain,
It may be branched or cyclic. Further, the alkyl group is
It is preferably unsubstituted in terms of synthesis. Specific examples represented by the formula (1) include an ethoxymethyl group, an ethoxyethyl group, an ethoxypropyl group, a propoxyethyl group, an n-butoxyethyl group, an iso-butoxyethyl group, a sec-butoxyethyl group, a t- Examples include, but are not limited to, butoxyethyl, cyclohexyloxymethyl, cyclohexyloxyethyl, menthyloxyethyl, isobornyloxyethyl, tetrahydrofuranyl, tetrahydropyranyl, and the like. Among them, an ethoxyethyl group, an n-propoxyethyl group, an isobutoxyethyl group, an ethoxypropyl group, and a cyclohexyloxyethyl group are preferable, and an ethoxyethyl group is particularly preferable.

On the other hand, the protecting group represented by the above formula (2)
Same molecule Formula be present alone in the chain may coexist different groups from each other represented by (2), R ₄ is C ₁ -C ₃
Is an alkyl group or an alkoxy group. That is, in the present invention, it is necessary to use a substituent (R ₄ ) having a carbon number of less than 4 as a substituent (R ₄ ) of the protective group represented by the formula (2) that forms the carbonyloxy skeleton. The alkyl group or the alkoxy group represented by R ₄ preferably has 2 carbon atoms.
~ 3. Specific examples include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group and the like, and preferably an alkoxy group. And particularly preferably an ethoxy group. When the number of carbon atoms is 4 or more, the hydrophobicity becomes too high, and when the focal length is shifted from the optimum focus (hereinafter, defocused), the shape is significantly deteriorated.

Further, in the present invention, the protection ratio (Pa mol%) of the base resin (that is, the resin before the protective group is introduced) by the group of the general formula (1) is also the same as that of the general formula (2). Must be greater than the protection ratio (Pb mol%). When this relationship is reversed, the solubility in the developer becomes insufficient, and a sufficient resolving power cannot be obtained.

Therefore, in consideration of image forming ability and heat resistance, the protection ratio by the protecting group (1) is usually from 10 to 60 mol% based on the total amount of the phenolic hydroxyl groups.
A more preferred introduction rate is 10 to 50 mol%.
More preferably, it is 10 to 40 mol%. The protecting group is eliminated by the action of an acid generated from a photoacid generator described later, and contributes to improving the solubility of the radiation-sensitive composition in a developer.

The protection ratio of the protecting group (2) is usually 5 to 45 mol% based on the total amount of the phenolic hydroxyl group in consideration of the image forming ability, particularly, the residual film property and the rectangularity. More preferably, it is 5 to 40 mol%, and still more preferably 5 to 30 mol%. Among them, the ratio of the protection rate by the protecting group of the formula (2) to the total protection rate by the protecting group of the formula (1) and the protecting group of the formula (2) [Pb × 100
/ (Pa + Pb)] is preferably 5% or more and less than 50%,
In particular, it is preferably from 10 mol% to 40 mol%. Furthermore,
When Pa and Pb satisfy the relationship of the following expression (3), it is particularly preferable in terms of the performance of the present invention.

[0024]

(3) 0.2 ≦ (Pa + Pb) /100≦0.6 (3)

The lower limit of the equation (3) is preferably 0.25, and the upper limit is 0.5. The weight-average molecular weight of the resin (a) varies depending on the introduction ratio of the protecting group and is larger than that of the base resin. However, even in this case, the weight-average molecular weight is usually expressed in terms of polystyrene (measured by gel permeation chromatography). Those having a molecular weight of 1,000 to 50,000, preferably 2,000 to 30,000, and more preferably 5,000 to 25,000 are used.
If the molecular weight is smaller than this range, a sufficient coating film as a resist cannot be obtained, and the heat resistance deteriorates. If the molecular weight is larger than this range, the solubility of the exposed portion in an alkali developing solution decreases, and the pattern of the resist decreases. Cannot be obtained.

Further, the resin (a) of the present invention preferably has a narrow molecular weight distribution (Mw / Mn). If the molecular weight distribution is wide, low molecular weight or high molecular weight polymers are present, heat resistance may be reduced if many low molecular weight polymers are present, and it is difficult to dissolve in alkali when many high molecular weight polymers are present. And may cause footing after pattern formation. Further, when a resin having a wide molecular weight distribution is protected by an acid-decomposable group, the solubility varies, and the development contrast between exposed and unexposed portions is reduced, so that it is difficult to obtain high resolution. Therefore, in order to obtain a resist material suitably used for fine pattern dimensions,
The molecular weight distribution of the resin (a) is 1.0 to 1.6, particularly 1.1.
It is preferable to have a narrow dispersion of ~ 1.4.

The resin (a) can be produced, for example, as follows. An alkali-soluble resin having a phenolic hydroxyl group such as polyvinyl phenol is dissolved in a solvent such as tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane or the like which dissolves the resin, and p-toluenesulfonic acid, hydrochloric acid, p-toluenesulfone is dissolved. In the presence of an acid catalyst such as an acid pyridinium salt, ethyl vinyl ether, ethyl-1-propenyl ether, a compound such as cyclohexyl vinyl ether is reacted with a part of the hydroxyl groups of the resin to etherify the product.
The resin (a) can be produced by reacting with diethyl carbonate, di (t-butyl) carbonate or isopropyloxycarbonyl chloride in the presence of a basic compound such as triethylamine. Resin (a)
Represents a hydroxyl group of a phenolic compound represented by the general formula (1),
Polymerizing a monomer containing a structure protected by the general formula (2),
It can also be manufactured by partial decomposition.

The proportion of the resin (a) in the radiation-sensitive composition of the present invention is based on 100 parts by weight of the solid content of the composition.
Usually 80 to 99.9 parts by weight, preferably 90 to 99.5
Parts by weight. In the radiation-sensitive composition of the present invention, in addition to the resin (a), some of the hydroxyl groups of the base resin and the base resin are protected with an acid-decomposable protecting group other than those described above, insofar as the performance of the composition is not impaired. It may contain other resins such as the above-mentioned resin.

The photoacid generator (b) of the present invention means a substance which generates an acid by the action of radiation such as light or electron beam used for exposure, and any substance having such an action can be used. Specifically, for example, triphenylsulfonium methanesulfonate,
Sulfonium salts such as triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroarsenate, triphenylsulfonium hexafluorophosphonate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium p -Toluenesulfonate, di (4-tertbutylphenyl) iodonium p-toluenesulfonate,
Iodonium salts such as di (4-tertbutylphenyl) iodonium camphorsulfonate, diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluoroarsenate, diphenyliodonium hexafluorophosphonate, methyl p-toluenesulfonate, ethyl p-toluenesulfonate, p -Butyl toluenesulfonate, phenyl p-toluenesulfonate, 1,2,3-tri (p-toluenesulfonyloxy) benzene, p-toluenesulfonic acid benzoin ester, methyl methanesulfonate, ethyl methanesulfonate, methanesulfonic acid Butyl, 1,2,3-tri (methanesulfonyloxy) benzene, phenyl methanesulfonate, benzoin methanesulfonate, trifluoromethanesulfonate Methyl, ethyl trifluoromethanesulfonate, butyl trifluoromethanesulfonate,
Sulfonates such as 1,2,3-tri (trifluoromethanesulfonyloxy) benzene, phenyl trifluoromethanesulfonate and benzoin trifluoromethanesulfonate, and o-nitrobenzyl such as o-nitrobenzyl-p-toluenesulfonate Esters, oxime sulfonates such as α- (4-nitrobenzenesulfonyloxyimino) -phenylacetonitrile, α- (p-toluenesulfonyloxyimino) -phenylacetonitrile, sulfones such as N, N′-di (phenylsulfonyl) hydrazide Hydrazides, disulfones such as diphenyldisulfone, bis (phenylsulfonyl) methane, bissulfonylmethanes such as bis (cyclohexylsulfonyl) methane, bis (phenylsulfonyl) Examples include bissulfonyldiazomethanes such as diazomethane and bis (cyclohexylsulfonyl) diazomethane. In particular, from the viewpoint of storage stability, bissulfonyldiazomethanes having a bissulfonyldiazomethane skeleton are preferred, and specifically, JP-A-9-5990, JP-A-4-219957, JP-A-5-249682 and JP-A-4-210960. And cyclohexylsulfonyl- (o-
(Methoxyphenylsulfonyl) diazomethane, cyclohexylsulfonyl- (p-methoxyphenylsulfonyl) diazomethane, cyclopentylsulfonyl- (o-
(Methoxyphenylsulfonyl) diazomethane, cyclopentylsulfonyl- (p-methoxyphenylsulfonyl) diazomethane, cyclohexylsulfonyl- (o-
(Fluorophenylsulfonyl) diazomethane, cyclohexylsulfonyl- (p-fluorophenylsulfonyl) diazomethane, cyclopentylsulfonyl- (o-
Fluorophenylsulfonyl) diazomethane, cyclopentylsulfonyl- (p-fluorophenylsulfonyl) diazomethane, cyclohexylsulfonyl- (o-
(Chlorophenylsulfonyl) diazomethane, cyclohexylsulfonyl- (p-chlorophenylsulfonyl) diazomethane, cyclopentylsulfonyl- (o-chlorophenylsulfonyl) diazomethane, cyclopentylsulfonyl- (p-chlorophenylsulfonyl) diazomethane, cyclohexylsulfonyl- (o-trifluoromethylphenylsulfonyl) Diazomethane, cyclohexylsulfonyl- (p-trifluoromethylphenylsulfonyl) diazomethane, cyclopentylsulfonyl-
(O-trifluoromethylphenylsulfonyl) diazomethane, cyclopentylsulfonyl- (p-trifluoromethylphenylsulfonyl) diazomethane, cyclohexylsulfonyl- (o-trifluoromethoxyphenylsulfonyl) diazomethane, cyclohexylsulfonyl- (p-trifluoromethoxyphenylsulfonyl )
Diazomethane, cyclopentylsulfonyl- (o-trifluoromethoxyphenylsulfonyl) diazomethane,
Cyclopentylsulfonyl- (p-trifluoromethoxyphenylsulfonyl) diazomethane, cyclohexylsulfonyl- (2,4,6-trimethylphenylsulfonyl) diazomethane, cyclohexylsulfonyl-
(2,3,4-trimethylphenylsulfonyl) diazomethane, cyclohexylsulfonyl- (2,4,6-triethylphenylsulfonyl) diazomethane, cyclohexylsulfonyl- (2,3,4-triethylphenylsulfonyl) diazomethane, cyclopentylsulfonyl- (2 , 4,6-Trimethylphenylsulfonyl) diazomethane, cyclopentylsulfonyl- (2,3,4-
Trimethylphenylsulfonyl) diazomethane, cyclopentylsulfonyl- (2,4,6-triethylphenylsulfonyl) diazomethane, cyclopentylsulfonyl- (2,3,4-triethylphenylsulfonyl) diazomethane, t-butylsulfonyl (2,4,6-trimethyl) Phenylsulfonyl) diazomethane, phenylsulfonyl (p-methoxyphenylsulfonyl) diazomethane, bis (o-methoxyphenylsulfonyl) diazomethane, bis (p-methoxyphenylsulfonyl) diazomethane, phenylsulfonyl- (2,4,6-trimethylphenylsulfonyl) Diazomethane, phenylsulfonyl- (2,3,4-trimethylphenylsulfonyl) diazomethane, phenylsulfonyl- (2,4,6
-Triethylphenylsulfonyl) diazomethane, phenylsulfonyl- (2,3,4-triethylphenylsulfonyl) diazomethane, 2,4-dimethylphenylsulfonyl- (2,4,6-trimethylphenylsulfonyl) diazomethane, 2,4-dimethylphenyl Sulfonyl- (2,3,4-trimethylphenylsulfonyl) diazomethane, phenylsulfonyl (o-fluorophenylsulfonyl) diazomethane, phenylsulfonyl (p
-Fluorophenylsulfonyl) diazomethane, cyclohexylsulfonyl- (β-naphthylsulfonyl) diazomethane, cyclopentylsulfonyl- (β-naphthylsulfonyl) diazomethane and the like.

These photoacid generators may be used alone or as a mixture of two or more of them. The total content of the photoacid generator is from 0.1 to 20 parts by weight, more preferably from 0.1 to 20 parts by weight, where the solid content of the radiation-sensitive composition is 100 parts by weight.
Used in 5 to 10 parts by weight. If the amount of the acid generator is less than this range, the sensitivity is inferior.If the amount of the acid generator is more than this range, the resist pattern becomes trapezoidal due to a decrease in the solubility of the resist film due to the acid generator, resulting in a decrease in resolution. May cause.

Additives can be added to the radiation-sensitive composition of the present invention to such an extent that the effects of the present invention are not impaired. Examples of the additive include a dissolution inhibitor, a nitrogen-containing compound, a surfactant, a dye, and a sensitizer. The dissolution inhibitor is a compound that controls the solubility of the unexposed portion of the resin (a) in an alkali developing solution, and may be a low-molecular compound or a high-molecular resin as long as it has a group that is eliminated by acid catalysis. .
Preferred are compounds in which a hydrogen atom of an acidic functional group such as a phenolic hydroxyl group or a carboxyl group is protected by a group capable of leaving by an acid catalyst. Specifically, Japanese Patent Application Laid-Open No. 9-6200
6, JP-A-9-278699, JP-A-9-50127,
Examples include compounds described in JP-A-9-166873 and JP-A-10-97075.

Further, the dissolution inhibitors used in the present invention can be used alone or in combination of two or more. When a dissolution inhibitor is added, the addition amount is usually 50 parts by weight or less, preferably 1 to 50 parts by weight, particularly preferably 5 to 3 parts by weight, based on 100 parts by weight of the solid component of the radiation-sensitive composition.
It is used in a proportion of 0 parts by weight. A nitrogen-containing compound is a compound that acts as a base with respect to an acid, and is used for sensitivity adjustment, or during the period from exposure to baking after exposure, an acid generated during prebaking or an acid generated from an acid generator during exposure. This is effective for preventing the resist pattern from moving and causing a dimensional change. Therefore, the compound is not particularly limited as long as it can neutralize the acid generated from the acid generator as described above, and examples thereof include an organic amide compound and an organic amine compound. Specifically, for example, pyrimidine, 2-aminopyrimidine, 4-aminopyrimidine, 5-aminopyrimidine, 2,4-diaminopyrimidine, 2,5-diaminopyrimidine, 4,5-diaminopyrimidine, 4,6-diamino Pyrimidine, 2,4,5-triaminopyrimidine,
2,4,6-triaminopyrimidine, 4,5,6-triaminopyrimidine, 2,4,5,6-tetraaminopyrimidine, 2-hydroxypyrimidine, 4-hydroxypyrimidine, 5-hydroxypyrimidine, 2,4 -Dihydroxypyrimidine, 2,5-dihydroxypyrimidine,
4,5-dihydroxypyrimidine, 4,6-dihydroxypyrimidine, 2,4,5-trihydroxypyrimidine, 2,4,6-trihydroxypyrimidine, 4,5
6-trihydroxypyrimidine, 2,4,5,6-tetrahydroxypyrimidine, 2-amino-4-hydroxypyrimidine, 2-amino-5-hydroxypyrimidine,
2-amino-4,5-dihydroxypyrimidine, 2-amino-4,6-dihydroxypyrimidine, 4-amino-
2,5-dihydroxypyrimidine, 4-amino-2,6
-Dihydroxypyrimidine, 2-amino-4-methylpyrimidine, 2-amino-5-methylpyrimidine, 2-amino-4,5-dimethylpyrimidine, 2-amino-4,
6-dimethylpyrimidine, 4-amino-2,5-dimethylpyrimidine, 4-amino-2,6-dimethylpyrimidine, 2-amino-4-methoxypyrimidine, 2-amino-5-methoxypyrimidine, 2-amino-4 , 5-Dimethoxypyrimidine, 2-amino-4,6-dimethoxypyrimidine, 4-amino-2,5-dimethoxypyrimidine, 4-amino-2,6-dimethoxypyrimidine, 2-
Hydroxy-4-methylpyrimidine, 2-hydroxy-
5-methylpyrimidine, 2-hydroxy-4,5-dimethylpyrimidine, 2-hydroxy-4,6-dimethylpyrimidine, 4-hydroxy-2,5-dimethylpyrimidine, 4-hydroxy-2,6-dimethylpyrimidine,
-Hydroxy-4-methoxypyrimidine, 2-hydroxy-4-methoxypyrimidine, 2-hydroxy-5-methoxypyrimidine, 2-hydroxy-4,5-dimethoxypyrimidine, 2-hydroxy-4,6-dimethoxypyrimidine, 4- Pyrimidine compounds such as hydroxy-2,5-dimethoxypyrimidine and 4-hydroxy-2,6-dimethoxypyrimidine; pyridine compounds such as pyridine, methylpyridine, N, N-dimethylaminopyridine and 2,6-dimethylpyridine; An alcohol substituted with a hydroxyalkyl group having 1 to 4 carbon atoms such as diethanolamine, triethanolamine, triisopropanolamine, tris (hydroxymethyl) aminomethane, and bis (2-hydroxyethyl) iminotris (hydroxymethyl) methane Amides, such as aminophenols such as 2-aminophenol, 3-aminophenol, and 4-aminophenol, and amides such as diethanolamide acetate, diethanolamide laurate, and diisopropanolamide stearate, which have a hydroxy group. Nitrogen-containing compounds are preferred, and amines or amides having a plurality of hydroxy groups in one molecule are particularly preferred. The content of the nitrogen-containing compound is usually appropriately selected from the range of 0.1 to 300 mol% based on the photoacid generator, but the content of the amines is based on the content of the photoacid generator. Thus, the content is preferably 0.1 to 100 mol%, more preferably 1 to 50 mol%. The content of the amide is 5 to 300 mol% based on the content of the photoacid generator.
Is more preferable, and more preferably 10 to 200 mol%. Other additives include a light absorbing agent described in JP-A-9-5990 and a carboxylic acid compound described in JP-A-9-6002 and 9-6003.

The radiation-sensitive composition of the present invention is used by dissolving it in a suitable solvent capable of dissolving the above-mentioned components such as the resin (a), photoacid generator, dissolution inhibitor and nitrogen-containing compound. Preferred solvents are cellosolve solvents such as methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, diethyl oxalate, ethyl pyruvate, ethyl-2-hydroxybutyrate, ethyl acetoacetate, butyl acetate,
Ester solvents such as amyl acetate, ethyl butyrate, butyl butyrate, methyl lactate, ethyl lactate, methyl 3-methoxypropionate, methyl 2-hydroxy-2-methylpropionate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene Propylene glycol solvents such as glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate, and dipropylene glycol dimethyl ether;
Examples thereof include ketone solvents such as cyclohexanone, methyl amyl ketone, and 2-heptanone, a mixed solvent thereof, and a solvent to which an aromatic hydrocarbon is further added. The ratio of the solvent used is desirably in the range of 1 to 20 times by weight based on the total amount of the solid content of the radiation-sensitive composition.

In the case of forming a resist pattern on a semiconductor substrate using the radiation-sensitive composition of the present invention, usually,
The radiation-sensitive composition of the present invention dissolved in a solvent as described above is applied on a semiconductor substrate, and can be used as a photoresist through each step of pre-baking, pattern transfer by exposure, baking after exposure, and development. . The semiconductor substrate is
Usually, it is used as a substrate for semiconductor manufacturing, such as a silicon substrate or a gallium arsenide substrate. still,
If necessary, various known antireflection films can be used on the substrate and the resist film.

For example, see JP-A-6-148896 and JP-A-6-148896.
-118630, 6-148896, 5-24
No. 1332, US Pat. No. 5,688,987, 569,369
No. 1, No. 536889, No. 5234990, No. 5
The antireflection film described in No. 110697 can be used. A spin coater is usually used for coating, and light having a wavelength of 200 to 300 nm, such as light of 157 nm, 193 nm, 222 nm, or 248 nm, or an electron beam using a low-pressure mercury lamp of 254 nm or an excimer laser as a light source is preferably used for exposure. In particular, it is advantageous to use an excimer laser as a light source. Light at the time of exposure may be broad instead of monochromatic light. Exposure using a phase shift method or modified illumination is also applicable.

The developer of the radiation-sensitive composition of the present invention includes:
Sodium hydroxide, potassium hydroxide, sodium carbonate,
Inorganic alkalis such as sodium silicate, sodium metasilicate, aqueous ammonia, primary amines such as ethylamine and n-propylamine, diethylamine, di-n
Secondary amines such as -propylamine; tertiary amines such as triethylamine and N, N-diethylmethylamine; quaternary ammonium salts such as tetramethylammonium hydroxide and trimethylhydroxyethylammonium hydroxide; To which alcohol, a surfactant and the like are added.

The radiation-sensitive composition of the present invention is useful not only for the production of VLSI but also for the production of general ICs, masks, images, liquid crystal screens, color filters or lithographic printing. is there. In particular, it is useful for making semiconductor integrated circuits and for deep ultraviolet exposure at a wavelength of 200 to 300 nm.

[0038]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited by the examples unless it exceeds the gist thereof.

Synthesis Example 1 Polyvinylphenol (weight average molecular weight 1500) was placed in a 1 L four-necked flask equipped with a nitrogen inlet tube, a stirrer, and a thermometer.
0) 90 g and 450 mL of 1,3-dioxolane were added and dissolved, and then 35.5 g of ethyl vinyl ether was added, followed by stirring for a while to obtain a uniform solution. 35%
0.15 ml of hydrochloric acid was added, the mixture was heated to 40 ° C. in a water bath, and stirring was continued for 2 hours. Thereafter, 28
2.5 mL of aqueous ammonia was added and stirred for 30 minutes. This reaction solution was dropped into 9 L of pure water, and the resulting precipitate was collected by filtration. Further, the precipitate was dissolved in acetone, and the solution was dropped into pure water to cause precipitation, thereby recovering a target resin. The collected resin was dried under vacuum to obtain 88 g of 1-ethoxyethylated polyvinyl phenol. In a 1 L four-necked flask equipped with a nitrogen inlet tube, a stirrer, and a thermometer, 10 g of the resin synthesized by the above method and 0.005 g of N, N
After adding and dissolving 45 mL of dimethylaminopyridine and acetone, 0.91 g of diethyl dicarbonate was added dropwise. The mixture was heated to 40 ° C. in a water bath and stirred overnight. The reaction solution was dropped into 1 L of pure water, and the obtained precipitate was collected by filtration. Further, the precipitate was dissolved in acetone, and the solution was dropped into pure water to cause precipitation, thereby recovering a target resin. The recovered resin is dried under vacuum and
g of resin were obtained. The weight average molecular weight of the obtained resin is 19
000. The obtained resin was dissolved in deuterated acetone, the proton NMR spectrum was measured, and the δ value was 6.2.
Aromatic-hydrogen signal of 7.0 and a δ value of 5.2-5.5
Of acetalumethine hydrogen and δ values of 4.1 to 4.
From the area ratio with the methylene hydrogen signal of 5, the introduction rates of the ethoxyethyl group (corresponding to the group of the general formula (1)) and the ethoxycarbonyl group (corresponding to the group of the general formula (2)) are 33%, 8%. The structure of the obtained resin is as follows. The degree of dispersion of the resin is 1.5.

[0040]

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Synthesis Example 2 10 g of a resin was obtained in the same manner as in Synthesis Example 1 except that the amount of ethyl vinyl ether was 34.0 g and the amount of diethyl dicarbonate was 1.3 g. The weight average molecular weight of the obtained resin was 19,000. The obtained resin was dissolved in deuterated acetone, and the proton NMR spectrum was measured. A signal of an aromatic hydrogen having a δ value of 6.2 to 7.0 and an acetal-methine hydrogen having a δ value of 5.2 to 5.5 were obtained. Signal and δ
Based on the area ratio of the signal of methylene hydrogen having a value of 4.1 to 4.5, the introduction ratio of an ethoxyethyl group (corresponding to the group of the general formula (1)) and an ethoxycarbonyl group (corresponding to the group of the general formula (2)) Was 28% and 12% respectively. The structure of the obtained resin is as follows. The degree of dispersion of the resin is 1.4.

[0042]

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Synthesis Example 3 9.5 g of a resin was obtained in the same manner as in Synthesis Example 1 except that di-t-butyl dicarbonate (1.5 g) was used instead of diethyl dicarbonate. The weight average molecular weight of the obtained resin was 20,000. The obtained resin is dissolved in deuterated acetone, ¹³ C-NMR spectrum is measured, and the introduction ratio of ethoxyethyl group (corresponding to the group of the general formula (1)) and t-butoxycarbonyl group is determined from the area ratio. And 28% and 10%, respectively. The structure of the obtained resin is as follows. The degree of dispersion of the resin is 1.4.

[0044]

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Example 1 1.0 g of the resin synthesized in Synthesis Example 1 was used as a photoacid generator.
A mixture of 0.02 g of cyclohexylsulfonyl- (4-methoxyphenylsulfonyl) diazomethane and 5.35 g of propylene glycol monomethyl ether acetate was mixed with bis (2-hydroxyethyl) iminotris (hydroxymethyl) methane as a nitrogen-containing compound. A photosensitizer was prepared by adding 15 mol% of a photoacid generator. This photosensitive liquid is applied on a silicon substrate by using a lower antireflection film (Br).
spin-coated on a wafer coated with DUV42 (Ear Science, Inc.)
The resist was baked at 60 ° C. for 60 seconds to form a resist film having a thickness of 0.72 μm. The resist film on this substrate was exposed using a KrF excimer laser reduction projection exposure apparatus (NA = 0.42) manufactured by Nikon Corporation, and baked on a hot plate at 110 ° C. for 60 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. By observing the resist pattern obtained after the development with a scanning electron microscope, the sensitivity, that is, 0.
30 μm line and space (L / S) is 1:
The exposure amount (hereinafter referred to as E0) and the resolution (limit resolution at the exposure amount E0) resolved to 1 were evaluated. Also,
0.30 μm line and space pattern and 0.2
The DOF of the 0 μm isolated line was evaluated. Sensitivity, resolution,
Table of DOF, pattern shape and edge roughness results
It is shown in FIG.

Example 2 and Comparative Example 1 A liquid was prepared and evaluated in the same manner as in Example 1 except that the resin in the resist photosensitive solution was changed to those shown in Table 1. The results are shown in Table 1. Comparative Example 2 Resin synthesized according to Synthesis Example 1 (weight average molecular weight 190
00, dispersity 1.4, ethoxyethyl group introduction rate 16
%, A resin having an ethoxycarbonyl group introduction rate of 24%) was evaluated in the same manner as in Example 1.
The pattern of / S was not resolved.

As is evident from Table 1, the resist using the resin of the present invention has a performance with lower edge roughness than the comparative example using a resin having a different protecting group or a resin having a different protection rate from the present invention. While maintaining, the pattern profile is good and the DOF is wide. In particular, as compared with the comparative example, even when defocused, the pattern shape does not become a shape such as T-top or undercut. Further, the resists of Examples 1 and 2 showed almost no change in the resist line width with respect to the withdrawal resistance up to exposure heat.

[0048]

[Table 1]

[0049]

According to the radiation-sensitive composition of the present invention, by using a resin having a specific structure as a component thereof,
While maintaining good sensitivity and resolving power, the edge roughness is small, the depth of focus is improved more than before, and a pattern having a good shape can be obtained even during defocusing, which is extremely useful practically in a semiconductor manufacturing process.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/027 H01L 21/30 502R F term (Reference) 2H025 AA00 AA01 AA02 AA03 AB03 AB08 AB13 AB16 AB17 AC04 AC08 AD03 BE00 BE10 BG00 BJ05 CB52 FA03 FA12 FA17 2H048 BA48 4J002 AA051 BC121 CC031 EV216 FD206 GP03

Claims (7)

[Claims] 1. An alkali-based compound having a phenolic hydroxyl group.
Low soluble phenolic hydroxyl groups in the same molecular chain
Trees at least partially protected by two or more different protecting groups
Radiation-sensitive group containing fat (a) and photoacid generator (b)
In the composition, the resin (a) has the following general formula as a protecting group:
A group containing the group of (1) and the group of the following general formula (2);
The protection ratio (Pa mol%) by the group of the general formula (1) is represented by the general formula:
The degree of protection by the group (2) (Pb mol%)
And a radiation-sensitive composition. Embedded image(Where R₁And R_TwoIs a hydrogen atom or
C that may be₁~ C ₆Represents an alkyl group represented by₁When
R_TwoMay combine to form a ring. R_ThreeIs C₁~ C₁₂
Is an optionally substituted alkyl group of_TwoAnd R_Three
May combine to form a ring. R_FourIs C₁~ C_ThreeNo
Represents an alkyl group or an alkoxy group. ) 2. In the general formula (1), R ₁ is a hydrogen atom, R ₂ is a C ₁ -C ₂ unsubstituted alkyl group,
Claim R ₃ is an unsubstituted alkyl group of C ₁ -C ₁₀ 1
The radiation-sensitive composition as described in the above. 3. In the general formula (2), R ₄ is C ₁ -C _3.
The radiation-sensitive composition according to claim 1, which is an unsubstituted alkoxy group. 4. The resin (a) having a degree of dispersion Mw / Mn of 1.0.
The radiation-sensitive composition according to any one of claims 1 to 3, wherein the composition is from 1.6 to 1.6. 5. The radiation-sensitive composition according to claim 1, wherein the photoacid generator (b) is a bissulfonyldiazomethane. 6. The radiation-sensitive composition according to claim 1, wherein Pa and Pb satisfy the following formula (3). (1) 0.20 ≦ (Pa + Pb) /100≦0.6 (3) 7. The radiation-sensitive resin composition according to claim 1, wherein Pa and Pb satisfy the following formula (4). ## EQU2 ## 5 ≦ (Pb × 100) / (Pa + Pb) <50 (4)