JP3249194B2 - Photosensitive resist composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive composition suitable as a resist for fine processing in a process for manufacturing a semiconductor device, particularly, a large-scale integrated circuit (LSI).

[0002]

2. Description of the Related Art In the manufacture of various electronic components such as semiconductor integrated circuits, a fine processing technique by photolithography is employed. Such techniques are specifically
It is implemented as the following process. That is, first, a photoresist film is formed on a semiconductor substrate such as a silicon wafer by a spin coating method or the like. Next, after subjecting the resist film to pattern exposure, development processing, rinsing processing, and the like are performed to form a desired resist pattern. Further, using this resist pattern as an etching resistant mask, the exposed substrate portion is etched to form fine lines and openings.

In particular, in recent years, in order to achieve high-density integration in accordance with high-density electronic components, in the above-described process,
It is required to form a finer resist pattern. In response to such demands, attempts have been made to shorten the wavelength of a radiation source used for exposure. For example, deep UV such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), other electron beams,
A lithography technique using X-rays or the like has been studied.

[0004] However, the conventional resist has a large absorption for the short-wavelength light described above, so that such light cannot sufficiently reach the deep portion of the resist film.
That is, in a region deep from the surface of the resist film, the chemical change due to exposure does not sufficiently proceed. As a result, the formed resist pattern has a triangular cross-sectional shape in a positive resist and an inverted triangular shape in a negative resist. When used as an etching-resistant mask, a fine pattern is accurately transferred to a substrate. There was a problem that it was not possible.

In order to solve such a problem, a resist called a chemically amplified type has been proposed. The chemically amplified resist contains, for example, a compound that generates a strong acid upon irradiation with light, that is, a photoacid generator and a compound in which a hydrophobic group is decomposed by the generated acid to change into a hydrophilic substance. It is a photosensitive composition. Specifically, H. It
o, C, G, Wilson, J .; M. J, Freche
t, U.S. Pat. No. 4,491,628 (1985) discloses a polymer in which hydroxyl groups of poly (p-hydroxystyrene) are blocked with butoxycarbonyl groups and a positive resist containing an onium salt as a photoacid generator. Have been. Also, M. J. O'Brien, J. et al. V. Criv
cell, SPIE Vol, 920, Advance
s in Resist Technology an
d Processing, p42, (1988) discloses a positive resist containing m-cresol novolak resin, naphthalene-2-carboxylic acid-tert-butyl ester, and a triphenylsulfonium salt as a photoacid generator. Further, H. Ito, SPIE Vol, 92
0, Advances in Resist Tech
noology and Processing, p3
3, (1988) discloses a positive resist containing 2,2-bis (4-tert-butoxycarbonyloxyphenyl) propane or polyphthalaldehyde and an onium salt as a photoacid generator.

[0006] In these chemically amplified resists, the acid generated from the photoacid generator acts as a catalyst, so that even a trace amount of the resist effectively causes a chemical change inside the resist. As a result, when the resist film is irradiated with radiation, the reaction sufficiently proceeds even in the inside of the film where the radiation is hard to reach compared to the film surface. As a result, a resist pattern having a steep side surface of the line portion can be formed by the development processing.

However, since the above-mentioned chemically amplified resist has high sensitivity, it is easily affected by oxygen, moisture and other trace components in the process atmosphere. In particular, the acid generated by light irradiation near the surface of the resist film is deactivated by a basic substance such as NH ₃ in the atmosphere, and the dissolution rate of the hardly-soluble layer on the film surface, that is, the developing solution is extremely low. This hardly-solubilized layer, which forms a layer, remains on the surface of the pattern formed after the exposure and development processes in an eaves-like manner.

FIG. 2 shows an example of a cross-sectional shape of a pattern formed using a conventional chemically amplified resist. As shown in the figure, a resist pattern 2 formed on a substrate 21 is formed.
In No. 2, the eaves are formed on the surface due to the above reason, and the lines and spaces having a desired width are not resolved.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a photosensitive composition suitable as a resist material applied to fine processing of a semiconductor device. It is highly sensitive to exposure to short-wavelength ultraviolet rays, X-rays, electron beams, etc., exhibits high resolution, and stably forms a fine pattern with a rectangular cross-section without generating eaves on the surface. It is to provide a photosensitive composition that can be used.

[0010]

Means for Solving the Problems and Functions of the Invention
The resist composition is represented by (a) any one of the following chemical formulas.
A compound having a substituent which can be decomposed by an acid compounded as a main component , and (b) 0.1 to 30 wt.
% UV, X-ray, electron beam, or
A compound that generates an acid by irradiation with an ion beam ;
(C) moles of the acid-generating compound as component (b)
An amine compound containing silicon compounded in a range of 1 to 200% or less with respect to the concentration is contained as an essential component.

Embedded image (Wherein, R ¹ represents a monovalent organic group, and m is an integer of 0 or more.
And n represents a positive integer. ) Photosensitive resist of the present invention
The composition corresponds to a so-called positive type chemically amplified resist. That is, in the resist film formed using the composition, the component (b) generates an acid in the exposed portion, and the acid functions as a catalyst to decompose the substituent of the component (a). As a result, a difference occurs in the dissolution rate of the exposed portion and the unexposed portion in a predetermined developing solution, and the exposed portion is selectively dissolved and removed by the treatment with the developing solution, thereby forming a resist pattern.

The composition of the present invention is most characteristic in that a component (c) comprising an amine compound containing silicon is added to the components (a) and (b). In the exposed part of the resist film made of the composition, the acid is prevented from being excessively deactivated near the surface by the component (c),
Since the acid concentration distribution in the film thickness direction becomes uniform, the decomposition reaction of the component (a) by the acid proceeds uniformly from the interface with the substrate to the surface, and no hardly soluble layer is formed particularly on the surface. . Further, in the unexposed portion of the resist film, excessive diffusion of the acid from the exposed portion is suppressed, and the decomposition reaction of the component (a) hardly occurs. Therefore, according to the photosensitive composition, the contrast between the exposed and unexposed portions is high, and a fine resist pattern having a rectangular cross section can be obtained.

FIG. 1 shows an example of a cross-sectional shape of a resist pattern that can be formed by the composition of the present invention. As shown in the figure, a pattern 12 having a rectangular cross section in which lines and spaces having a constant width are secured in the film thickness direction is formed on a substrate 11. Hereinafter, each component contained in the composition of the present invention will be described in detail.

The compound having a substituent which can be decomposed by an acid, which is the component (a), is not particularly limited as long as it is a compound which can be decomposed by an acid and change the solubility in a predetermined developing solution. Esters or ethers based on compounds are mentioned. Such esters and ethers are, specifically, esterified or etherified to a hydroxyl group (phenolic hydroxyl group) in a phenol compound with an appropriate esterifying agent or etherifying agent, that is, by introducing an ester bond or an ether bond, The alkali affinity is suppressed. still,
The esters and ethers are insoluble in an alkali solution when not exposed, but when exposed, the component (b)
It is decomposed by the acid generated from, and changes to a compound exhibiting alkali solubility. Therefore, when the composition of the present invention contains the ester and the ether as the component (a), development using an alkali solution can be performed.

Examples of the phenol compound serving as the base of the ester or ether include phenol, cresol, xylenol, bisphenol A, bisphenol S, hydroxybenzophenone, phenolphthalein, phenol novolak resin, cresol novolak resin, xylenol novolak resin, and polyvinyl phenol. , Isopropenylphenol resin, copolymer of vinylphenol with acrylic acid, methacrylic acid derivative, acrylonitrile, styrene derivative, etc., copolymer of isopropenylphenol with acrylic acid, methacrylic acid derivative, acrylonitrile, styrene derivative, etc., styrene Derivatives and acrylic resin, methacrylic resin, acrylic acid,
Copolymers with methacrylic acid, maleic acid, maleic anhydride, acrylonitrile, and the like, or compounds containing silicon in the structure of these polymers can be given.

The ester or ether to be introduced includes, for example, methyl ester, ethyl ester, n-
Propyl ester, iso-propyl ester, tert-butyl ester, n-butyl ester, iso-butyl ester,
Benzyl ester, tetrahydropyranyl ether, benzyl ether, methyl ether, ethyl ether, n-
Propyl ether, iso-propyl ether, tert-butyl ether, allyl ether, methoxymethyl ether, p-bromophenacif ether, trimethylsilyl ether, benzyloxycarbonyl ether, tert-butoxycarbonyl ether, tert-butyl acetate,
4-tert-butylbenzyl ether and the like can be mentioned.

Particularly, as the component (a), a polymer represented by the following general formula (I) among the above-mentioned compounds is preferable.

[0017]

Embedded image

(Wherein, R ¹ represents a monovalent organic group, m represents an integer of 0 or more, and n represents a positive integer.) The monovalent organic group introduced into the general formula (I) Examples of the group R ¹ include methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, iso-butyl, sec-butyl, benzyl and the like. Of these, especially tert
-Butyl is preferred.

In the polymer of the general formula (I), n / (m
+ N) is preferably in the range of about 0.03-1, more preferably 0.05-0.70. The reason is that n
If the value of / (m + n) is less than 0.03, the difference in dissolution rate between the exposed part and the unexposed part of the photosensitive composition (resist film) becomes small, and the resolution of the formed pattern may be reduced. Because there is.

The molecular weight of the polymer of the general formula (I) is preferably at least about 3,000 from the viewpoint of improving heat resistance, because the compatibility between the polymer and other components and the development of the photosensitive composition can be improved. It is preferably about 15,000 or less from the viewpoint of improving the properties. Further, the value of the ratio Mw / Mn of the weight average molecular weight Mw and the number average molecular weight Mn of the polymer is preferably about 1.5 or more.

The component (b) which is a compound capable of generating an acid upon irradiation with light, ie, a photoacid generator, is not particularly limited, and various known compounds and mixtures can be used. For example, onium salts, organic halogen compounds,
Orthoquinone-diazide sulfonic acid chloride, sulfonic acid esters and the like can be mentioned. Examples of the onium _{salts, CF 3 SO 3 -, p} -CH 3 PhSO 3 -,
Examples thereof include diazonium salts, phosphonium salts, sulfonium salts, and iodonium salts having p-NO ₂ PhSO ₃ — or the like as a counter anion.

The organic halogen compound is a compound that forms hydrohalic acid, and is disclosed in, for example, US Pat. No. 3,515,552, US Pat. No. 3,536,489, US Pat. No. 3,779,778, and West German Patent Publication No. 2,243,621. Examples include: Other photoacid generators other than those described above include, for example,
4-74728, JP-A-55-24113, JP-A-55-77742, JP-A-60-3626, JP-A-60-138439, JP-A-56-17345, and JP-A-50-50 No. 36209.

Specific examples of such compounds include:
Diphenyliodonium trifluoromethanesulfone
DOO, benzoin tosylate, ortho-nitrobenzyl p-toluenesulfonate, triphenylsulfonium trifluoromethanesulfonate, tri (tert-butylphenyl) sulfonium trifluoromethane sulfonate, diazonium p-toluenesulfonate, 4- (di-n- propylamino) - Benzoniumu Tetrafluoroborate, 4-p-tolyl-mercapto-
2,5-diethoxy-benzenediazonium hexafluorophosphate , diphenylamine-4-diazonium sulfate, 4-methyl-6-trichloromethyl-
2-pyrone, 4- (3,4,5-trimethoxy-styryl) -6-trichloromethyl-2-pyrone, 4- (4-
(Methoxy-styryl) -6- (3,3,3-trichloro-propenyl) -2-pyrone, 2-trichloromethyl-
Benzimidazole, 2-tribromomethyl-quinolone, 2,4-dimethyl-1-tribromoacetyl-benzene, 4-dibromoacetyl-benzoic acid, 1,4-bis-dibromomethyl-benzene, tris-dibromomethyl-S -Triazine, 2- (6-methoxy-naphthyl-2)
-Yl) -4,6-bis-trichloromethyl-S-triazine, 2- (naphthyl-1-yl) -4,6-bis-
Trichloromethyl-S-triazine, 2- (naphthyl-
2-yl) -4,6-bis-trichloromethyl-S-triazine, 2- (4-ethoxyethyl-naphthyl-1-
Yl) -4,6-bis-trichloromethyl-S-triazine, 2- (benzopyran-3-yl) -4,6-bis-trichloromethyl-S-triazine, 2- (4-methoxy-anthrac-1-) Yl) -4,6-bis-trichloromethyl-S-triazine, 2- (phenanth-9-
Yl) -4,6-bis-trichloromethyl-S-triazine, o-naphthoquinonediazide-4-sulfonic acid chloride and the like.

Examples of the sulfonic acid ester include naphthoquinonediazide-4-sulfonic acid ester, naphthoquinonediazide-5-sulfonic acid ester and p-toluenesulfonic acid-
o-nitrobenzyl ester, p-toluenesulfonic acid -2,
6-dinitrobenzyl ester and the like can be mentioned.
Examples of the sulfonic acid ester include o-quinonediazidesulfonic acid ester, and for example, an ester of o-quinonediazidesulfonic acid and a phenol compound is preferable. The ester can be synthesized by reacting o-quinonediazidesulfonic acid chloride with a phenol compound in a conventional manner. Here, as o-quinonediazide sulfonic acid chloride, for example, 1-benzoquinone
2-diazo-4-sulfonic acid chloride, 1-naphthoquinone-
2-diazo-4-sulfonic acid chloride, 1-naphthoquinone-2-
Diazo-4-sulfonic acid chloride. On the other hand, phenolic compounds include phenol, cresol, xylenol, bisphenol A, bisphenol S, hydroxybenzophenone, 3,3,3,3-tetramethyl-1,1-spirobiindane-5,6,7,5,6,7 -Hexanol, phenolphthalein, dimethyl p-hydroxybenzylidenemalonate, dinitrile p-hydroxybenzylidenemalonate, cyanophenol, nitrophenol, nitrosophenol, hydroxyacetophenone, methyl trihydroxybenzoate, polyvinylphenol, novolak resin, etc. . Among these, an ester of 1-naphthoquinone-2-diazo-4-sulfonic acid and 2,3,4-trihydroxybenzophenone or 2,3,4,4-tetrahydroxybenzophenone is particularly preferable.

In the photosensitive composition of the present invention, the content of the photoacid generator as the component (b) is preferably about 0.1 to 30% by weight based on the total solid content of the composition (resist).
More preferably, it is in the range of 0.5 to 20% by weight. If the amount of the photoacid generator is less than 0.1% by weight, sufficient photosensitivity may not be obtained. On the other hand, 30% by weight
If it exceeds 300, it may be difficult to form a uniform resist film, or residues may be generated on the substrate surface when the resist film is removed after the pattern formation and etching steps.

The silicon-containing amine compound as the component (c) is not particularly limited, and examples thereof include the following compounds. That is, N- (3-acryloxy-2-hydroxypropyl) -3-aminopropyltriethoxysilane, 4-aminobutyldimethylmethoxysilane, 4-aminobutyltriethoxysilane, N- (2-aminoethyl) -3- Aminopropylmethyldimethoxysilane, N- (2-aminomethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltris (2-ethylhexoxy) silane, 6- (aminohexylamino Propyl) trimethoxysilane, p-aminophenyltrimethoxysilane, 3- (1-aminopropoxy) -3,3-dimethyl-1-propenyltrimethoxysilane, 1,3-bis (4-aminobutyl)
Tetramethyldisiloxane, bis (p-aminephenoxy) dimethylsilane, 1,3-bis (3-aminopropyl) tetramethyldisiloxane, 1,4-bis (3-aminopropyldimethylsilyl) benzene, 1,3- Bis (3-aminopropyl) -1,3-dimethyl-1,3-diethoxydisiloxane, (aminoethylaminomethyl) phenethyltrimethoxysilane, 3-aminopropyldiethylmethylsilane, N-benzyl-trimethylsilylmethylaminoacetonitrile , Bis (dimethylamino) diphenylsilane, bis (diethylamino) dimethylsilane, bis (dimethylamino) methylphenylsilane, bis (dimethylamino) methylvinylsilane, bis (mono-n-butylamino) dimethylsilane, bis (monoethylamino) ) Dimethylsilane, bis [3- (triethoxysilyl) propyl ] Amine, N-6,9-
Bis (trimethylsilyl) adenine, bis (trimethylsilyl) cytosine, bis (trimethylsilyl) hypoxanthine bis-N, N- (trimethylsilyl) piperazine, bis (o-trimethylsilyl) thymine, t-butylaminotriethylsilane, t-butyldimethylsilylimidazole ,
t-butyldimethylsilylimidazole, t-butyldimethylsilylpyrrole, (N, N-diethyl-3-aminopropyl) trimethoxysilane and the like.

Particularly, as the amine compound containing silicon as the component (c), a siloxane compound represented by the following general formula (II) is preferable.

[0028]

Embedded image

(In the formula, R ² and R ³ represent a divalent organic group, R ^{4 to} R ⁷ represent a monovalent organic group, and L represents a positive integer.) The general formula (II) Examples of the divalent organic groups R ² and R ³ to be introduced into m are methylene, ethylene, propylene, butylene, pentylene, phenylene and the like. Examples of the monovalent organic groups R ^{4 to} R ⁷ include methyl, ethyl, n-propyl, tert-butyl, iso-butyl, sec-butyl, n-hexyl, cyclohexyl, phenyl and the like.

As the component (c), the compound represented by the general formula (II)
Of the compounds represented by the formula, 1,3-bis (4-aminobutyl)
Most preferred are tetramethyldisiloxane and 1,3-bis (3-aminobutyl) tetramethyldisiloxane. In the photosensitive composition of the present invention, the compounding amount of the amine compound containing silicon as the component (c) is based on the molar concentration of the photoacid generator as the component (b) in the composition (resist).
The molar concentration of the amine compound is preferably about 1-20.
0%, particularly preferably in the range of about 10-100%. When the amount of the amine compound is such that the molar concentration is less than 1%, the formation of the hardly-solubilized layer on the resist film surface may not be sufficiently suppressed. If the amount is more than 200%, sufficient photosensitive performance may not be obtained.

The photosensitive composition of the present invention allows the addition of an alkali-soluble polymer in addition to the components (a), (b) and (c). By blending an appropriate amount of such an alkali-soluble polymer, the dissolution rate of the resist film comprising the photosensitive composition in an alkaline solution can be adjusted. As a result, when a development process using an alkaline solution is performed, the resolution of the formed pattern can be further increased.

Examples of the alkali-soluble polymer include phenol novolak resin, cresol novolak resin, xylesol novolak resin, polyvinylphenol, isopropenylphenol resin, vinylphenol and acrylic acid, methacrylic acid derivative, acrylonitrile, styrene derivative and the like. Copolymer of isopropenylphenol with acrylic acid, methacrylic acid derivative, acrylonitrile, styrene derivative, etc .; copolymer of styrene derivative with acrylic acid, methacrylic acid, maleic acid, maleic anhydride, acrylonitrile, etc. Examples thereof include polymers and compounds containing silicon in the structure of these polymers. Among these, a polymer having an aromatic ring is preferred from the viewpoint of improving the dry etching resistance of the resist. Specifically, phenol novolak resin, cresol novolak resin, xylesol novolak resin, polyvinyl phenol, and isopropenyl phenol resin are preferable.

In the composition of the present invention, when the alkali-soluble polymer is blended, the blending amount is determined by the total amount of the compound having a substituent which can be decomposed by an acid as the component (a) and the alkali-soluble polymer. Preferably not more than about 90 parts by weight, more preferably 8 parts by weight, per 100 parts by weight.
0 parts by weight or less. If the blending amount of the alkali-soluble polymer exceeds 90 parts by weight, the difference in the dissolution rate of the exposed part and the unexposed part in the developer in the radiation-sensitive layer becomes small, and the resolution in pattern formation may be reduced.

The composition of the present invention comprises the above component (a),
In addition to (b) and (c), a surfactant as a coating film modifier or a dye as an antireflection agent is allowed as necessary. The photosensitive composition of the present invention is obtained by dissolving the above components (a), (b) and (c), an alkali-soluble polymer and the like, and other additives, if necessary, in a suitable organic solvent. And is prepared in the form of a varnish by filtration. Such organic solvents include, for example, cyclohexanone, acetone, methyl ethyl ketone,
Ketone solvents such as methyl isobutyl ketone, methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve,
Cellosolve solvents such as butyl cellosolve acetate, ethyl acetate, butyl acetate, isoamyl acetate, ethyl lactate,
Examples thereof include ester solvents such as methyl lactate, N-methyl-2-pyrrolidone, dimethylformamide, and dimethyl sulfoxide. These solvents are xylene,
An appropriate amount of an aliphatic alcohol such as toluene or isopropylene alcohol may be contained. These solvents may be used alone or in the form of a mixture.

Hereinafter, an example of a process for forming a resist pattern using the photosensitive composition of the present invention will be described in detail along the steps. First, as a first step, the photosensitive composition of the present invention prepared in the form of a varnish is applied to a substrate by, for example, a spin coating method or a dipping method, and then is applied at about 150 ° C. or lower, preferably 70 to 120 ° C. To form a resist film.

As the substrate, for example, a silicon wafer, a silicon wafer having steps on the surface on which various insulating films, electrodes, and wirings are formed, a blank mask, GaAs,
III-V compound semiconductor wafers such as AlGaAs. Next, as a second step, the resist film is subjected to pattern exposure using ultraviolet light, ionizing radiation, or the like.
In the step, the photoacid generator as the component (b) generates an acid in the exposed portion of the resist film, and the acid reacts with the compound having a substituent which can be decomposed by the acid in the component (a). Decomposes the compound.

The ultraviolet rays used in this step include, for example, i-line, h-line, g-line of a mercury lamp, KrF line and ArF line as an excimer laser, and ionizing radiation includes X-ray and electron beam. And an ion beam.
In this step, when ultraviolet rays are used, the resist film can be exposed through a mask having a desired pattern. On the other hand, when using an electron beam, an ion beam, or the like,
By scanning these radiations without using a mask, pattern drawing (exposure) can be performed directly on the resist film.

Subsequently, the resist film after pattern exposure is
If necessary, baking is generally performed at a temperature of about 70 to 160 ° C., preferably 80 to 150 ° C. to diffuse the acid generated in the exposed portion of the resist film as described above, and the acid and the component (a) Reaction can be promoted. The reason for limiting the temperature in the post-exposure bake is that if the temperature is lower than 70 ° C., it may be difficult to carry out the above reaction sufficiently. This is because the part and the unexposed part may be decomposed or cured.

Next, as a third step, the exposed or baked resist film is developed using, for example, an alkaline aqueous solution. By this process, the exposed portion of the resist film is selectively removed, and a pattern composed of lines and spaces of a predetermined width is formed. Examples of the alkaline aqueous solution that can be used as a developer in this step include, for example, an inorganic alkaline aqueous solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, sodium silicate, and sodium metasilicate; an aqueous tetramethylammonium hydroxide solution; An organic alkali aqueous solution such as an ethylammonium hydroxide aqueous solution, or a solution obtained by adding an alcohol, a surfactant, or the like thereto can be used.

After the development, the developing solution (alkaline aqueous solution) is washed away with water, and the substrate is dried. In addition, after the development processing, the substrate is gradually heated to cross-link the resin component included in the formed pattern, or a step bake is performed. By performing deep UV curing for cross-linking, the heat resistance of the pattern can be improved.

In the pattern formation process as described above, before the second step, ie, before the exposure, the surface of the resist film is exposed to an acidic water-soluble polymer, a neutral water-soluble polymer, or a non-local solvent. A coating layer made of a soluble polymer may be formed. When these coating layers are formed, the underlying resist film is protected from trace components in the atmosphere, so that the formation of a hardly soluble layer on the resist film surface is further suppressed.

Specifically, when an acidic or neutral water-soluble polymer is used, the coating film is dissolved in pure water to prepare an aqueous polymer solution, and is further dissolved in a non-local solvent. When using the obtained polymer, a polymer solution in the solvent is prepared, and the solution is applied on the resist film by a spin coating method or a dipping method, and then dried at about 150 ° C. or lower, preferably 120 ° C. or lower. Can be formed by

Examples of the acidic water-soluble polymer include a polymer having a carboxy group or a sulfo group as a substituent, and a copolymer containing a monomer unit having a carboxy group or a sulfo group. Specific examples include polyacrylic acid, polymethacrylic acid, polystyrene sulfonic acid, polymaleic acid, polyitaconic acid, itaconic acid-acrylic acid copolymer, itaconic acid-methacrylic acid copolymer, ethylene-maleic anhydride copolymer, Ethylene-methacrylic acid polymer, methyl vinyl ether-maleic anhydride copolymer, styrene-maleic anhydride copolymer, isobutylene
-Maleic anhydride copolymers and copolymers obtained by reacting the above-mentioned copolymer containing maleic anhydride as a constituent unit with alcohol to partially esterify the copolymer.
Here, the alcohol used for partial esterification includes methyl alcohol, ethyl alcohol, n-propyl alcohol, and isopropyl alcohol. These acidic water-soluble polymers may be used alone or in the form of a mixture of two or more. Among the acidic water-soluble polymers exemplified above, the copolymer containing maleic anhydride, when dissolved in pure water in the process of forming the coating layer, cleaves the anhydride bond in maleic anhydride to form a carboxylic acid. It changes to acid and becomes acidic.

The coating film made of the acidic water-soluble polymer is subjected to pattern exposure together with the resist film and, if necessary, baking, followed by development with an aqueous alkali solution. Through the portion, it can be dissolved and removed together with the exposed portion of the resist film. Further, the coating film composed of the acidic water-soluble polymer can be dissolved and removed with pure water after exposure and before development. In particular, when the coating layer is removed before the development processing, it is possible to prevent the alkali concentration of the alkaline developer from changing during the development processing due to the influence of the acidic component constituting the coating layer. As a result, a high-resolution pattern can be stably formed.

Examples of the neutral water-soluble polymer include polyvinyl alcohol. The coating layer made of the polymer can be dissolved and removed with pure water after being exposed together with the resist film and, if necessary, subjected to a heat treatment. As the polymer that can be dissolved in the nonpolar solvent,
For example, a rubber-based polymer, polysiloxane and the like can be mentioned. Examples of the non-polar solvent include hexane, heptane, toluene, xylene and the like. The coating layer made of the polymer can be dissolved and removed by the non-polar solvent after being exposed together with the resist film and, if necessary, subjected to a heat treatment.

The coating layer is allowed to contain a surfactant as a coating modifier, if necessary. Nonionic surfactants are suitable for such surfactants. Specific examples thereof include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene polyoxypropylene block copolymer, sorbitan fatty acid ester, fatty acid Examples include alkylolamide, polyoxyethylene lanolin alcohol ether, and polyoxyethylene lanolin fatty acid ester. The coating layer containing such an interface modifier is preferable in that precipitation of a polymer in a subsequent step can be prevented.

The thickness of the coating layer is preferably about 10
１０００1000 nm, more preferably 50-500 nm. When the thickness of the coating layer is less than 10 nm,
There is a possibility that it may be difficult to sufficiently achieve the effect of preventing the formation of the hardly-solubilized layer on the surface of the radiation-sensitive layer. On the other hand, if the thickness of the coating layer exceeds 1000 nm, the resolution of the formed pattern may be reduced. The thickness of the acidic coating layer does not depend on the thickness of the lower radiation-sensitive layer, but can be appropriately determined by assuming the thickness of the hardly-solubilized layer formed on the surface of the radiation-sensitive layer.

[0048]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments. These examples are described for the purpose of facilitating understanding of the present invention, and do not particularly limit the present invention.

Synthesis of Compound Having Substituent Decomposable by Acid In a nitrogen-substituted four-necked flask, 50 g of polyvinylphenol (PHM-C: manufactured by Maruzen Petroleum Co., Ltd.) was added to acetone 20
The resulting solution was added with 17.63 g of potassium carbonate, 8.48 g of potassium iodide and 24.38 g of tert-butyl bromoacetate, and refluxed for 7 hours while stirring. Subsequently, after removing insoluble components by filtration, acetone was distilled off and the residue was dissolved in 150 ml of ethanol. The resulting solution was dropped into 1.5 liters of water to precipitate a polymer. The polymer was washed 5 more times with 300 ml of water and air dried for 12 hours. Air-dried polymer,
Dissolve again in 200 ml of ethanol and reprecipitate by the same operation.
After purification, the polymer was dried in a vacuum dryer at 50 ° C. for 24 hours to obtain 52.0 g of a polymer. When the obtained polymer was analyzed by ¹ H-NMR spectrum, it was confirmed that 20% of the hydroxyl groups in polyvinyl phenol as the base polymer had been changed to tert-butoxycarbonyl ether. Hereinafter, this polymer (a compound having a substituent which can be decomposed by an acid) is referred to as TB
Called CM20.

Further, a compound having a substituent decomposable by the following acid based on polyvinyl phenol was synthesized according to the same method as described above.

[0051]

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Compounds which generate an acid upon irradiation with light The following compounds A1 to A6 were prepared. A1: Trisphenylsulfonyl trifluoromethanesulfonate A2: Diphenyliodonium trifluoromethanesulfonate A3: 2,3,4,4-tetrahydroxybenzophenone and 1,
Ester with 2-naphthoquinonediazide-4-sulfonic acid (esterification ratio 3/4) A4: p-toluenesulfonic acid-2,6-dinitrobenzyl ester A5: bis (phenylsulfonyl) methane A6: bis (phenylsulfonyl) Diazomethane Amine compound containing silicon

The following amine compounds B1 to B4 were prepared. B1: 1,3-bis (3-aminopropyl) tetramethyldisiloxane B2: 1,3-bis (4-aminobutyl) tetramethyldisiloxane B3: bis (p-aminophenoxy) dimethylsilane B4: p-amino Phenyltrimethoxysilane

Preparation of photosensitive composition Compound TBCM20 having a substituent decomposable by an acid
3.0 g of a compound A1 which generates an acid upon irradiation with light
0.093 g and the amine compound B1 containing silicon.
018 g was dissolved in 9 g of 1-acetoxy-2-ethoxyethane (ethyl cellosolve acetate) to give a pore size of 0.2
The photosensitive composition R1 was prepared in the form of a solution (varnish) by filtration using a μm filter.

In the same manner, photosensitive compositions R2 to R10 were prepared in the form of solutions according to the formulations shown in Table 1 below.

[0056]

[Table 1]

Example 1 A solution of the photosensitive composition R1 was spin-coated on 6-inch silicon, and prebaked on a hot plate at 95 ° C. for 90 seconds to form a resist film having a thickness of 1.0 μm. did. Subsequently, pattern exposure was performed on the resist film through a mask having a predetermined pattern using a KrF excimer laser stepper. Exposed resist film 95
Baked on a hot plate at 90 ° C. for 90 seconds, immersed in a 2.38% by weight aqueous solution of tetramethylammonium hydroxide (hereinafter referred to as “TMAH aqueous solution”) for 50 seconds, developed, washed with water and dried, and then resist-patterned. I got Observation of this pattern with an electron microscope revealed that a line and a space having a width of 0.28 μm were resolved at an exposure dose of 50 mJ / cm ² . The cross section of this pattern was rectangular as shown in FIG.

Examples 2 to 10 Each of the solutions of the photosensitive compositions R2 to R10 was spin-coated on a 6-inch silicon wafer, and a resist film was formed by pre-baking under the conditions shown in Table 2 below. After performing a developing process, the product was washed with water and dried to obtain a resist pattern.

These patterns were observed with an electron microscope in the same manner as described above. Table 2 also shows the results of the sensitivity (exposure amount) and the resolution. Further, the cross sections of these patterns were all rectangular as shown in FIG.

[0060]

[Table 2]

Example 11 A solution of the photosensitive composition R1 was spin-coated on 6-inch silicon and prebaked to form a 1.0 μm thick resist film. Subsequently, S is added to this resist film.
Proximity exposure was performed using OR light (synchro-orbital radiation light). After baking the exposed resist film on a hot plate at 95 ° C. for 90 seconds,
It was immersed in a 2.38% by weight aqueous solution of TMAH for 50 seconds for development, washed with water and dried to obtain a resist pattern. Observation of this pattern with an electron microscope revealed that lines and spaces having a width of 0.20 μm were resolved at an exposure dose of 250 mJ / cm ² . The cross section of this pattern was rectangular as shown in FIG.

Example 12 A solution of the photosensitive composition R1 was spin-coated on 6-inch silicon and prebaked to form a 0.5 μm-thick resist film. Subsequently, an electron beam at an acceleration voltage of 20 kV was pattern-drawn (irradiated) on the resist film.
After baking the resist film after the electron beam irradiation on a hot plate at 80 ° C. for 90 seconds, a 2.38% by weight concentration of TMA was obtained.
The resist pattern was obtained by immersing in an H aqueous solution for 50 seconds for development, washing and drying with water. When this pattern was observed with an electron microscope, the exposure amount was 10 μC / cm ² ,
Lines and spaces having a width of 0.20 μm were resolved. The cross section of this pattern was rectangular as shown in FIG.

Comparative Example Compound TBCM20 having an acid-decomposable substituent
3.0 g of a compound A1 which generates an acid upon irradiation with light
0.093 g and 1 g of 1-acetoxy-2-ethoxyethane
And filtered with a filter having a pore size of 0.2 μm to prepare a photosensitive composition Q1 containing no silicon-containing amine compound in a solution (varnish) state.

Using this composition Q1, a resist pattern was formed in the same manner as in Example 1. When the cross section of the obtained pattern was observed with an electron microscope, as shown in FIG. 2, eaves were formed on the upper part of the line, and the desired line and space were not resolved. From the above results, according to the photosensitive composition obtained by adding a compound having a substituent decomposed by an acid and a compound generating an acid by light irradiation to an amine compound containing silicon, a hardly soluble layer is formed on the film surface. Is suppressed, and it is confirmed that a pattern having a rectangular cross section can be formed without generating eaves.

[0065]

As described in detail above, according to the present invention,
Photosensitivity that is highly sensitive to exposure to short-wavelength ultraviolet rays, X-rays, electron beams, etc., exhibits high resolution, and can stably form a fine pattern with a rectangular cross-section without generating eaves on the surface. Composition. Furthermore, it becomes possible to perform etching with high processing accuracy using such a pattern as a mask. Therefore, the composition of the present invention can be effectively applied to an ultra-fine processing process in the production of semiconductor devices such as LSIs, and its industrial value is extremely large.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the shape of a pattern formed using the photosensitive composition of the present invention.

FIG. 2 is a sectional view showing the shape of a pattern formed using a conventional chemically amplified resist.

[Explanation of symbols]

 11, 21 ... substrate, 12, 22 ... resist pattern

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naohiko Chisato 1 Toshiba, Komukai, Kawasaki, Kanagawa Prefecture Inside Toshiba Research Institute, Inc. (72) Inventor Hiromitsu Wakabayashi Toshiba, Komukai, Kawasaki, Kanagawa 1 Toshiba Research Institute, Inc. (56) References JP-A-5-181279 (JP, A) JP-A-4-211258 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) G03F 7/00-7/42 C08F 212/14

Claims (3)

(57) [Claims] (A) represented by any one of the following chemical formulas:
A compound having a substituent that can be decomposed by an acid compounded as a main component , and (b) a compound of 0.1 to 30% by weight based on the total solid content.
A compound that generates an acid by irradiation with deep ultraviolet rays, an X-ray, an electron beam, or an ion beam; and (c) a mole of the compound that generates an acid as the component (b).
A photosensitive resist composition comprising, as an essential component, an amine compound containing silicon blended in a range of 1 to 200% with respect to the concentration . Embedded image (Wherein, R ¹ represents a monovalent organic group, and m is an integer of 0 or more.
And n represents a positive integer. ) 2. The value of n / (m + n) in said chemical formula
The photosensitive material according to claim 1, wherein is in the range of 0.03 to 1.
Resist composition. 3. The value of n / (m + n) in said chemical formula
Is 0.05-0. 2. The method according to claim 1, wherein the value is within the range of 70.
Photosensitive resist composition.