JP2001264970A - Pattern forming resist and pattern forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pattern forming resist having high sensitivity to UV and ionizing radiation and also having high resolution. SOLUTION: The pattern forming resist contains (a) a compound having an acid decomposable substituent, (b1) a compound which generates a strong acid when irradiated with light and (b2) a compound which generates a weak acid when irradiated with light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist for forming a pattern and a method for forming a pattern used for fine processing of a semiconductor device, particularly, a large-scale semiconductor integrated circuit (LSI).

[0002]

2. Description of the Related Art In the process of manufacturing a semiconductor device such as an LSI,
Fine processing technology by photolithography is employed. Such a technique, for example, a photoresist film is formed on a substrate such as a silicon single crystal wafer by a spin coating method or the like, and after pattern exposure of the resist film, development, rinsing or the like is performed to form a resist pattern, Further, a method of forming fine lines and windows by etching the exposed substrate using the resist pattern as an etching mask.

In the manufacture of the above-mentioned LSI, finer processing technology is required with the increase in integration of the LSI. In response to such demands, attempts have been made to shorten the wavelength of an exposure light source. Specifically, a lithography technique using deep UV light such as a KrF excimer laser or an ArF excimer laser as a light source is known.

However, since the conventional resist has a large absorption for light of a short wavelength, the light sufficiently reaches a portion distant from the surface of the resist film, for example, a portion on the substrate side covered with the resist film. Can not do. For this reason, the cross-sectional shape of the developed resist pattern becomes an inverted triangle. As a result, when the resist pattern is used as an etching mask for a substrate or the like, there has been a problem that the pattern cannot be accurately transferred to the substrate or the like.

As a resist that solves such a problem, a chemically amplified resist has been proposed. The chemically amplified resist includes a compound that generates a strong acid upon irradiation with light (photoacid generator) and a compound that decomposes a hydrophobic group by an acid to change the group into a hydrophilic substance. Specifically, H. It
o, C, G, Wilson, J .; M. J. Franch
et, U.S.A. S. Patent 4,491,628 (1
No. 985) discloses a positive resist containing a polymer obtained by blocking a hydroxyl group of poly (p-hydroxystyrene) with a butoxycarbonyl group and an onium salt which is a compound capable of generating an acid upon irradiation with light. Also, M. J. O'B
Rien, J. et al. V. Crivello, SPIE Vo
1,920, Advances in Resist
Technology and Processin
g, p42, (1988), m-cresol novolak resin and naphthalene-2-carboxylic acid-tert.
-Positive resists containing butyl esters and triphenylsulfonium salts have been published. Furthermore, H. It
o, SPIE Vol, 920, Advances i
n Resist Technology and P
processing, p33, (1988)
A positive resist containing 2,2-bis (4-tert-butoxycarbonyloxyphenyl) propane, polyphthalaldehyde and an onium salt has been disclosed.

[0006] Since the photoacid generator acts as a catalyst,
Reacts efficiently even in small amounts. Therefore, when the resist film is irradiated with light, the reaction sufficiently proceeds even in the interior where the light is hard to reach compared to the surface. As a result, a resist pattern having a steep side surface can be formed by the development processing.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to have high sensitivity and high resolution to ultraviolet rays and ionizing radiation,
An object of the present invention is to provide a resist for pattern formation suitable for an ultrafine processing step in the manufacture of a semiconductor device.

Another object of the present invention is to provide a method capable of forming a fine pattern having a rectangular cross section.

[0009]

The resist for pattern formation according to the present invention comprises (a) a compound having a substituent capable of being decomposed by an acid, (b1) a compound capable of generating a strong acid upon irradiation with light, and (b2) a compound capable of generating a strong acid upon irradiation with light. And a compound that generates a weak acid upon irradiation.

The pattern forming method according to the present invention comprises the steps of (a)
A resist for pattern formation containing a compound having a substituent capable of being decomposed by an acid, (b1) a compound generating a strong acid upon irradiation with light, and (b2) a compound generating a weak acid upon irradiation with light, is applied to a substrate. The pattern is exposed, heated, and then developed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The pattern forming resists (1) to (3) according to the present invention will be described in detail below.

Pattern-forming resist (1) This pattern-forming resist comprises (A) a compound having a substituent which is decomposed by an acid represented by the following general formula (I) and (B) light irradiation: And a compound capable of generating an acid.

[0013]

Embedded image

In the formula (I), R ¹ is a monovalent organic group, m is 0 or a positive number of 1 or more, and n is a positive number.

R ¹ introduced into the general formula (I) is 1
The organic group is not particularly limited as long as it is a valent organic group. For example, methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, iso-butyl, sec-butyl, benzyl and the like can be used. In particular, ter
t-Butyl is preferred.

N / (m + n) in the general formula (I)
Is 0.03 to 1, more preferably 0.05 to 0.1.
It is desirably in the range of 70. The reason for this is that n
If the value of / (m + n) is less than 0.03, the dissolution rate difference between the exposed and unexposed areas may be small, and the resolution may be reduced. This is because there is a possibility that the pattern may be formed or the pattern surface may be roughened.

The compound represented by formula (I) desirably has a molecular weight of 1,000 or more from the viewpoint of improving heat resistance.

As the compound (B) which generates an acid (strong acid) upon irradiation with light, various known compounds and mixtures can be used. For example, diazonium salts,
C of phosphonium salt, sulfonium salt and iodonium salt
F ₃ SO ₃ ⁻ , p-CH ₃ PhSO ₃ ⁻ , p-NO ₂ P
Examples thereof include salts such as hSO ₃ ⁻ (where Ph is a phenyl group), organic halogen compounds, orthoquinone-diazidosulfonyl chloride, and sulfonic acid esters. The organic halogen compound is a compound that forms hydrohalic acid, and such a compound is disclosed in US Pat.
No. 5,552, U.S. Pat. No. 3,536,489, U.S. Pat. No. 3,779,778 and West German Patent Publication No. 2243.
621. Compounds which generate an acid upon irradiation with another light as described above are described in JP-A-54-7.
4728, JP-A-55-24113, JP-A-55-24113
77742, JP-A-60-3626, JP-A-60-60
No. 138,539, JP-A-56-17345 and JP-A-50-36209.

Specific examples of such compounds include:
Di (p-tert-butylphenyl) iodonium trifluoromethanesulfonate, diphenyliodonium trifluoromethanesulfonate, benzoin tosylate, orthonitrobenzyl paratoluenesulfonate, triphenylsulfonium trifluoromethanesulfonate, tri (tert-butylphenyl) sulfonium trifluoromethanesulfonate, Benzenediazonium paratoluenesulfonate, 4- (di-n-propylamino) -bensonium tetrafluoroborate, 4
-P-tolyl-mercapto-2,5-diethoxy-benzenediazonium hexafluorophosphate, tetrafluoroborate, 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-quinoline, 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-anthracy-1) -Yl) -4,6-bis-trichloromethyl-S-triazine, 2- (phenanthine-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, p-toluenesulfonic acid-o-nitrobenzyl ester, p-toluenesulfonic acid-2,6-dinitrobenzyl ester and the like. Can be mentioned.

As the component (B), which is a compound which generates an acid upon irradiation with light, it is particularly preferable to use an o-quinonediazide compound. The o-quinonediazide compound is not particularly limited, but is preferably an ester of o-quinonediazidesulfonic acid and a phenol compound. o-
An ester of quinonediazidesulfonic acid and a phenol compound can be obtained by reacting o-quinonediazidesulfonic acid chloride with a phenol compound according to a conventional method. Examples of the o-quinonediazidesulfonic acid chloride include 1-benzophenone-2-diazo-4-sulfonic acid chloride, 1-naphthoquinone-2-diazo-5-sulfonic acid chloride,
Naphthoquinone-2-diazo-4-sulfonic acid chloride and the like can be used. Examples of the phenol compound 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, dintrile p-hydroxybenzylidenemalonate, cyanophenol, nitrophenol, nitrosophenol, hydroxyacetophenone, methyl trihydroxybenzoate, polyvinylphenol, novolak resin, etc. it can. Such o-quinonediazide compounds are specifically exemplified in Tables 1 to 5 below.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

[Table 3]

[0024]

[Table 4]

[0025]

[Table 5]

Among the o-quinonediazide compounds, 1-naphthoquinone-2-diazo-4-sulfonic acid ester is particularly preferred. Such esters are described in J. Grun
Wald, C, Gal, S, Eidelman, SPI
E Vol, 1262, Advances in Re
sist Technology and Process
As disclosed in ssingVII, p444, (1990), it is known that light irradiation produces carboxylic acids and sulfonic acids, which are stronger acids than carboxylic acids, and is particularly effective because of its large catalytic activity.

The compound capable of generating an acid (strong acid) upon irradiation with light contains 0.1% of the total solid component in the resist for pattern formation.
It is desirable that the content be 1 to 30% by weight, more preferably 0.5 to 20% by weight. This is for the following reason. When the compounding amount of the compound is less than 0.1% by weight, it becomes difficult to obtain sufficient photosensitive characteristics. On the other hand, if the compounding amount of the compound exceeds 30% by weight, it may be difficult to form a uniform resist film, or residues may be generated during removal after development or etching.

The resist for forming a pattern is allowed to contain a carboxylic acid as a third component in addition to the components (A) and (B). Such a carboxylic acid is blended to increase the dissolution rate in an alkaline aqueous solution and to reduce eaves generated on the pattern surface. The carboxylic acid is not particularly limited as long as it is uniformly mixed in the resist for pattern formation. Specifically, formic acid, acetic acid, propionic acid, butyric acid, 2-methylpropanoic acid, valeric acid, isovaleric acid, α-methylbutyric acid, trimethylacetic acid, hexanoic acid, 4-methylpentanoic acid, 2-methylbutanoic acid, 2, 2
-Dimethylbutanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, eiconic acid, docosanoic acid, hexacosanoic acid, triaconic acid, oxalic acid, Malonic acid, succinic acid, glutanic acid,
Adipic acid, pimelic acid, suberic acid, azelaic acid,
Sebacic acid, ascorbic acid, tridencanedioic acid, methylmalonic acid, ethylmalonic acid, dimethylmalonic acid, methylsuccinic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylsuccinic acid, tetramethylsuccinic acid, 1,2,2 3-propanetricarboxylic acid, 1,2,3-propenetricarboxylic acid, 2,3-dimethylbutane-1,2,3-tricarboxylic acid, fluoroacetic acid, trifluoroacetic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, bromoacetic acid Iodoacetic acid, 2-chloropropionic acid, 3-chloropropionic acid, 2-bromopropionic acid, 3-bromopropionic acid, 2-iodopropionic acid, 2,3-dichloropropionic acid, chlorosuccinic acid, bromosuccinic acid, 2, 3-dibromosuccinic acid, hydroxyacetic acid, lactic acid, 2-hydroxybutyric acid, 2-hydric Carboxymethyl-2-methylpropanesulfonic acid, 2-
Hydroxy-4-methylpentanoic acid, 3-hydroxy-
3-pentanecarboxylic acid, 3-hydroxypropionic acid, 10-hydroxyoctanedecanoic acid, 3,3,3-
Trichloro-2-hydroxypropionic acid, 2- (lactoyloxy) propionic acid, glyceric acid, 8,9-
Dihydroxyoctadecanoic acid, tartronic acid, malic acid, acetoxysuccinic acid, 2-hydroxy-2-methylbutanedioic acid, 3-hydroxypentanedioic acid, tartaric acid, d
-Ethyl bitartrate, tetrahydroxysuccinic acid, citric acid, 1,2-dihydroxy-1,1,2-ethane-tricarboxylic acid, ethoxyacetic acid, 2,2'-oxydiacetic acid, 2,3-epoxypropionic acid, Pyruvic acid, 2-
Oxobutyric acid, acetoacetic acid, 4-oxovaleric acid 9,10-
Dioxooctadecanoic acid, mesooxalic acid, oxaloacetic acid, 3-oxoglutanic acid, 4-oxoheptanediacid,
Benzoic acid, toluic acid, ethylbenzoic acid, p-isopropylbenzoic acid, 2,3-dimethylbenzoic acid, 2,4-dimethylbenzoic acid, 2,5-dimethylbenzoic acid, 3,5-
Dimethylbenzoic acid, 2,4,5-trimethylbenzoic acid,
Phthalic acid, isophthalic acid, terephthalic acid, 5-methylisophthalic acid, 1,2,3-benzenetricarboxylic acid,
1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, 1,2,3,4-benzenetetracarboxylic acid, 1,2,3,5-benzenetetracarboxylic acid, 1,2,2 4,5-benzenetetracarboxylic acid, benzenepentacarboxylic acid, benzenehexacarboxylic acid,
Fluorobenzoic acid, chlorobenzoic acid, dichlorobenzoic acid, trichlorobenzoic acid, bromobenzoic acid, dibromobenzoic acid, iodobenzoic acid, chlorophthalic acid, dichloroflutic acid, tetrachlorophthalic acid, nitrosobenzoic acid, o
-Nitrobenzoic acid, p-nitrobenzoic acid, 2,4-dinitrobenzoic acid, 2,4,6-trinitrobenzoic acid, 3-
Nitrobenzoic acid, 5-nitroisophthalic acid, 2-nitroterephthalic acid, p-hydroxybenzoic acid, salicylic acid,
5-chlorosalicylic acid, 3,5-dichlorosalicylic acid,
3-nitrosalicylic acid, 3,5-dinitrosalicylic acid,
2,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid, 2,3,4-tri Hydroxybenzoic acid, 2,4
6-trihydroxybenzoic acid, 6-hydroxy-2-toluic acid, 2-hydroxy-3-toluic acid, 6-hydroxy-3-toluic acid, 2-hydroxy-4-toluic acid, 2-hydroxy-3-isopropyl -6-methylbenzoic acid, 4-hydroxy-5-isopropyl-2-methylbenzoic acid, 2,4-dihydroxy-6-methylbenzoic acid, 2-hydroxyphthalic acid, 4-hydroxyisophthalic acid, 2-hydroxyterephthalic acid 3,4-dihydroxyphthalic acid, 2,5-dihydroxyphthalic acid, 2-
Hydroxy-1,3,5-benzenetricarboxylic acid,
(Hydroxymethyl) benzoic acid, (1-hydroxy-1
-Methylethyl) benzoic acid, anisic acid, vanillic acid, 3
-Hydroxy-4-methoxybenzoic acid, 3,4-dimethoxybenzoic acid, 3,4-methylenedioxybenzoic acid,
3,4,5-trimethoxybenzoic acid, 3,4-dimethoxyphthalic acid, o-phenoxybenzoic acid, o-acetoxybenzoic acid, 3-o-galloyl gallic acid, p-acetylbenzoic acid, p-benzoylbenzoic acid, 4,4'-carbonyldibenzoic acid, p-acetamidobenzoic acid, o-benzoamidobenzoic acid, phthalanilic acid, phenylacetic acid, 2-
Phenylpropionic acid, 3-phenylpropionic acid, 4
-Phenylbutyric acid, p-hydroxyphenylacetic acid, 2,5
-Dihydroxyphenylacetic acid, 3- (o-hydroxyphenyl) propionic acid, 2,3-dibromo-phenylpropionic acid, α-hydroxyphenylacetic acid, 2-hydroxy-2-phenylpropionic acid, 2-hydroxy-3
-Phenylpropionic acid, 3-hydroxy-2-phenylpropionic acid, 3-hydroxy-3-phenylpropionic acid, 2,3-epoxy-3-phenylpropionic acid, phenylsuccinic acid, o-carboxyphenylacetic acid,
1,2-benzenediacetic acid, phenylglyoxylic acid, o
-Carboxyglyoxylic acid, phenylpyruvic acid,
Benzoylacetic acid, 3-benzoylpropionic acid, phenoxyacetic acid, benzoyloxyacetic acid, 2-benzoyloxypropionic acid, succinanilic acid, carbanilic acid, oxanilic acid, o-carboxyoxanilic acid, 4-biphenylcarboxylic acid, 2,2′- Biphenyldicarboxylic acid,
Benzylbenzoic acid, diphenylacetic acid, α-hydroxydiphenylacetic acid, o-benzhydrinbenzoic acid, phenolphthalein, triphenylacetic acid, uvic acid, 5-methyl-2-furancarboxylic acid, 2-furancarboxylic acid, furic acid, paracone Acids, terenic acid, terpenylic acid, aconic acid, coumaric acid, comic acid, comenic acid, kelidonic acid, meconic acid and the like can be mentioned.

The carboxylic acid is desirably contained at 0.5 to 20% by weight, more preferably 1 to 10% by weight, in all solid components of the resist for pattern formation. This is for the following reason. When the amount of the carboxylic acid is less than 0.5% by weight, it becomes difficult to improve the pattern shape after formation, exposure and development of a resist film. On the other hand, if the amount of the carboxylic acid is more than 20% by weight, the difference in dissolution rate between the exposed and unexposed portions becomes small during the formation of the resist film and the development after the exposure, which may lower the resolution.

The resist for pattern formation is allowed to contain an alkali-soluble polymer as a fourth component in addition to the components (A) and (B).

As the alkali-soluble polymer, a resin containing an aryl group or a carboxy group into which a hydroxy group has been introduced is desirable. Specifically, phenol novolak resin, cresol novolak resin, xylesol novolak resin, vinyl phenol resin, isopropenyl phenol resin, copolymers of vinyl phenol with acrylic acid, methacrylic acid derivative, acrylonitrile, styrene derivative, etc. Copolymer of propenylphenol with acrylic acid, methacrylic acid derivative, acrylonitrile, styrene derivative, etc., copolymer of styrene derivative with acrylic resin, methacrylic resin, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, acrylonitrile, etc. Or a compound containing silicon in these polymers. However, from the viewpoint of resistance during dry etching, a resin containing an aromatic ring is preferable, and examples thereof include a phenol novolak resin and a cresol novolak resin. Specific alkali-soluble polymers are listed in Tables 6, 7, and 8 below. Further, quinone in the phenol resin generated by the oxidation may be reduced to improve the transparency.

[0032]

[Table 6]

[0033]

[Table 7]

[0034]

[Table 8]

When the total amount of the alkali-soluble polymer and the compound having a substituent which is decomposed by an acid is 100 parts by weight, the alkali-soluble polymer is 90 parts by weight or less, more preferably 80 parts by weight or less. It is desirable to do. The reason for this is that if the blending amount of the alkali-soluble polymer exceeds 90 parts by weight, the difference in dissolution rate between the exposed and unexposed parts is small, and the resolution may be reduced.

Further, in addition to the components (A) and (B), the carboxylic acid and the alkali-soluble polymer, a sensitizer, a dye, a surfactant, a dissolution inhibitor may be used, if necessary. Agents are allowed.

The resist for forming a pattern is prepared by dissolving the components (A) and (B), and the carboxylic acid, alkali-soluble polymer, and the like, if necessary, in an organic solvent, followed by filtration. You. Examples of such organic solvents include ketone solvents such as cyclohexanone, acetone, methyl ethyl ketone and methyl isobutyl ketone, methyl cellosolve, methyl cellosolve acetate, and the like.
Cellosolve solvents such as ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, and butyl cellosolve acetate; ester solvents such as ethyl acetate, butyl acetate, isoamyl acetate, ethyl lactate, and methyl lactate;
Methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide and the like can be mentioned. These solvents may be used alone or in the form of a mixture. However, these may contain an appropriate amount of an aliphatic alcohol such as xylene, toluene or isopropyl alcohol.

Pattern-forming resist (2) This pattern-forming resist comprises (a) a compound having a substituent capable of being decomposed by an acid, (b) a compound capable of generating an acid upon irradiation with light, and (c) a carboxylic acid. Is included.

The compound having a substituent which is decomposed by an acid, which is the component (a), is not particularly limited as long as it is decomposed by an acid and changes the solubility in a developing solution. Ethers are preferred. Examples of the phenol compound 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, polyvinylphenol, novolak resin and the like. it can. These hydroxy groups are esterified or etherified using a suitable esterifying or etherifying agent. As the ester or ether to be introduced, 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. In particular, the compound is preferably a compound represented by the general formula (I) which is the component (A) described in the pattern forming resist (1).

As the compound (b), which is a compound which generates an acid upon irradiation with light, the same compound as described in the pattern forming resist (1) can be used. In particular, various known compounds and mixtures can be used as the component (b) by using the carboxylic acid as the component (c) in combination. However, as the compound, o- described in the pattern forming resist (1) is used.
It is preferable to use a quinonediazide compound.
-Naphthoquinone-2-diazo-4-sulfonic acid ester is most preferred.

The compound as the component (b) is contained in the total solid component of the resist for pattern formation in an amount of 0.1 to 30 for the same reason as described for the component (B) of the resist for pattern formation (1). Wt%, more preferably 0.5-20
% By weight.

As the carboxylic acid as the component (c), the same carboxylic acids as those listed as the third component of the pattern forming resist (1) are used. The carboxylic acid is contained in the entire solid component of the resist for pattern formation in an amount of 0.5 to 20% by weight, more preferably 1 to 10% by weight, for the same reason as described in the resist for pattern formation (1). It is desirable.

The resist for pattern formation may further comprise the same alkali-soluble polymer as described for the resist for pattern formation (1) in addition to the components (a), (b) and (c). It is allowed to be blended as a component. When the total amount of the compound having a substituent that is decomposed by an acid and the alkali-soluble polymer is 100 parts by weight, as described in the pattern-forming resist (1), the alkali-soluble polymer is 90 parts by weight. It is desirable that the compounding amount be not more than 80 parts by weight, more preferably not more than 80 parts by weight.
In particular, when neither of the components (a) and (b) takes the form of a polymer, it is preferable to incorporate the alkali-soluble polymer as the fourth component.

Further, the pattern forming resist is allowed to contain a sensitizer, a dye, a surfactant, and a dissolution inhibitor as required.

As the resist for pattern formation, the components (a), (b) and (c), and the alkali-soluble polymer compounded as required, were used in the resist for pattern formation (1). It is prepared by dissolving in the same organic solvent as described above and filtering.

Pattern-forming resist (3) This pattern-forming resist comprises (a) a compound having a substituent which is decomposed by an acid, (b1) a compound which generates a strong acid upon irradiation with light, and (b2) a compound which generates a strong acid upon irradiation with light. And a compound generating a weak acid.

As the compound (a) having a substituent which is decomposed by an acid, which is the component (a), the same compounds as those described for the pattern forming resist (2) can be used. Particularly, the compound represented by the general formula (I) is preferable.

The compound as the component (b1) has a strong acid such as pK (K is the ionization constant of the electrolyte) of 3 when irradiated with light.
It is a compound that generates an acid that is less than. The compound is
The same compound as the component (B) described in the pattern forming resist (1) can be used. In particular, as the compound, it is preferable to use the o-quinonediazide compound described in the pattern forming resist (1), and 1-naphthoquinone-2-diazo-4-sulfonic acid ester is most preferable.

The compound as the component (b1) is desirably contained in an amount of 0.1 to 20% by weight, more preferably 0.5 to 10% by weight, based on all solid components of the resist for pattern formation. This is for the following reason.
When the compounding amount of the compound is less than 0.1% by weight, it becomes difficult to obtain sufficient photosensitive characteristics. On the other hand, if the compounding amount of the compound exceeds 20% by weight, it may be difficult to form a uniform resist film, or residues may be generated during removal after development or etching.

The compound (b2) has a weak acid, for example, pK (K is the ionization constant of the electrolyte) of 3 when irradiated with light.
It is a compound that generates the acid described above. Examples of the compound include 1,2-naphthoquinonediazide-5-sulfonic acid ester, 5-diazomeldrum acid and derivatives thereof, and diazodimedone derivatives.

It is desirable that the compound (b2) be contained in an amount of 1 to 30% by weight, more preferably 5 to 20% by weight, based on all solid components of the resist for pattern formation.
This is for the following reason. If the compounding amount of the compound is less than 1% by weight, it becomes difficult to suppress the formation of a hardly soluble layer on the resist surface. On the other hand, if the compounding amount of the compound exceeds 30% by weight, it may be difficult to form a uniform resist film, or residues may be generated during removal after development or etching.

The resist for forming a pattern comprises, in addition to the components (a), (b1) and (b2), a carboxylic acid similar to that described for the resist for forming a pattern (1), a fourth component, It is permitted to contain an alkali-soluble polymer as the fifth component, respectively. The carboxylic acid is contained in the total solid component of the resist for pattern formation in an amount of 0. 0 for the same reason as described in the resist for pattern formation (1).
It is desirable to contain 5 to 20% by weight, more preferably 1 to 10% by weight. When the total amount of the compound having a substituent that is decomposed by an acid and the alkali-soluble polymer is 100 parts by weight, as described in the pattern-forming resist (1), the alkali-soluble polymer is 90 parts by weight.
It is desirable that the compounding amount be not more than 80 parts by weight, more preferably not more than 80 parts by weight. In particular, the above (a), (b1), (b2)
When none of the components takes the form of a polymer, it is preferable to incorporate the alkali-soluble polymer as the fifth component.

Further, the pattern forming resist is allowed to contain a sensitizer, a dye, a surfactant, and a dissolution inhibitor as required.

The resist for pattern formation is prepared by combining the components (a), (b1), and (b2), and the carboxylic acid, alkali-soluble polymer, and the like blended as necessary. It is prepared by dissolving in the same organic solvent as used in the above and filtering.

Next, a pattern forming method according to the present invention will be described.

First, the resists (1) to (3) for pattern formation are applied on a substrate by a spin coating method or a dipping method, and then dried at 150 ° C. or less, preferably 70 to 120 ° C. to form a resist film. I do. As the substrate used here, for example, a silicon wafer, a silicon wafer having steps on the surface of which various insulating films and electrodes, wirings are formed, a blank mask, a GaAs, an AlGaAs, etc., III-V
Group semiconductor wafers.

Next, pattern exposure is performed by selectively irradiating the resist film with ultraviolet rays (particularly, deep UV) or ionizing radiation through a mask having a desired pattern. At this time, for example, the pattern forming resist (1)
In the resist film consisting of, the compound which generates an acid by light irradiation as the component (B) therein generates an acid by light irradiation, and the acid is decomposed by the acid as the component (A) in the resist film. Reacts with compounds having a substituent. Examples of the ultraviolet light include KrF, ArF, XeF, and XeCl.
Excimer laser such as i-line, h-line, g of mercury lamp
Lines or the like can be used. As the ionizing radiation,
For example, an electron beam, an X-ray, or the like can be used. In the pattern exposure step, pattern exposure may be performed directly on the resist film by scanning the electron beam without using the mask.

Next, the resist film after the pattern exposure is heated at, for example, 70 to 160 ° C., preferably 80 to 150 ° C. At this time, the reaction between the acid generated in the resist film and a compound having a substituent decomposed by the acid in the resist film is promoted. The reason for limiting the temperature in the heating step is as follows. When the temperature is lower than 70 ° C., the reaction between the acid from the compound that generates an acid upon irradiation with light and the compound having a substituent that is decomposed by the acid cannot be sufficiently performed. On the other hand, if the temperature exceeds 160 ° C., the exposed portion and the unexposed portion of the resist film are decomposed or cured.

Next, the resist film after the heat treatment is developed with, for example, an aqueous alkali solution to form a desired resist pattern. Examples of the alkaline aqueous solution used here include an inorganic alkaline aqueous solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, sodium silicate, and sodium metasilicate; an organic aqueous solution such as an aqueous tetramethylammonium hydroxide solution and an aqueous trimethylhydroxyethylammonium hydroxide solution. Alkaline aqueous solution,
Alternatively, those to which an alcohol, a surfactant, or the like is added can be used. Then, after the developer is washed away with water, the substrate is dried.

In the pattern forming method according to the present invention, after the development processing, the substrate is gradually heated to perform a step bake for cross-linking the resin component of the resist pattern, or to irradiate deep UV while heating to form a resin for the resist pattern. Allow deep UV curing to crosslink the components. By performing such processing, the heat resistance of the pattern can be improved.

Further, in the pattern forming method according to the present invention, the resist film is allowed to be immersed in a low-concentration aqueous alkali solution before or after exposure, and then subjected to a subsequent development process. By performing such a process, the dissolution rate of the unexposed portion of the resist film can be reduced, and the contrast of the relief image can be improved. In the treatment, the resist film may be immersed in an amine such as trimethylamine, triethanolamine, hexamethylsilazane or the like instead of the alkaline aqueous solution, or may be exposed to the vapor of these amines. After exposing the substrate to an aqueous alkaline solution, heat treatment may be performed as necessary.

Further, in the pattern forming method according to the present invention, it is allowed to perform fog exposure by irradiating the entire surface of the resist film with heating while heating after the pattern exposure. By performing such a process, the dissolving speed of the unexposed portion of the resist film can be reduced to improve the resolution.

Further, when the pattern forming resist (1) is used in the pattern forming method according to the present invention, it is allowed to form a coating layer made of an acidic water-soluble polymer on the surface of the resist film before exposure. I do. The coating layer is prepared by dissolving the acidic water-soluble polymer in pure water to prepare a polymer aqueous solution, and applying the polymer aqueous solution to the surface of the resist film by a spin coating method or a deposition method. , Preferably by drying at 120 ° C or lower. By forming such a coating layer, it is possible to prevent a hardly soluble layer from being formed on the surface of the resist film.

The acidic water-soluble polymer forming the coating layer is preferably a polymer having a carboxy group or a sulfo group as a substituent. Specifically, polyacrylic acid, polymethacrylic acid, polystyrene sulfonic acid, polymaleic acid, polyitaconic acid, ethylene-maleic anhydride copolymer, ethylene-methacrylic acid polymer, methyl vinyl ether-maleic anhydride copolymer, styrene A maleic anhydride copolymer; The acidic water-soluble polymer may be used alone or in the form of a mixture of two or more. When the acidic water-soluble polymer is dissolved in the pure water, for example, when the water-soluble polymer is a copolymer of maleic anhydride, the anhydride bond is cleaved and the carboxylic acid is cleaved. Becomes acidic.

The coating layer is allowed to contain a surfactant as a coating modifier as needed.

The thickness of the coating layer is 10 to 10000 n
m, more preferably in the range of 50 to 500 nm. When the thickness of the coating layer is less than 10 nm, it is difficult to sufficiently achieve the effect of preventing the formation of a hardly-solubilized layer on the surface of the resist film. On the other hand, when the thickness of the coating layer exceeds 1000 nm, the resolution in pattern formation is reduced. May be reduced. The thickness of the coating layer does not depend on the thickness of the resist film, but is appropriately determined depending on the degree of the hardly-solubilized layer.

The resist film on which the coating layer is formed is developed with an aqueous alkali solution after pattern exposure and heat treatment. By this developing treatment, the coating layer is completely removed from the resist film regardless of the exposed portion and the unexposed portion, and further, the exposed portion or the unexposed portion of the resist film thereunder is selectively removed to form a resist pattern. You. However, it is allowed that the coating layer is removed with pure water before the developing treatment, and then the resist film is developed. By removing the coating layer before the development processing in this way, it is possible to avoid that the alkali concentration of the alkaline aqueous solution which is a developing solution is changed by the acidic water-soluble polymer forming the coating layer during the development processing, and it is stable. It is possible to ensure the resolution of the resist pattern.

[0068]

The resist for pattern formation according to the present invention (1)
According to this, the compound (B) in the resist, which generates an acid upon irradiation with light, acts as a dissolution inhibitor in an unexposed portion, while it generates an acid in an exposed portion where light irradiation is performed.
The compound having a substituent decomposed by the acid represented by the general formula (I), which is the component (A) in the resist, is decomposed by the acid generated from the component (B) to generate a carboxylic acid. For this reason, it becomes very easy to dissolve in a developing solution composed of an alkaline aqueous solution. On the other hand, conventionally used compounds having a substituent that can be decomposed by many acids are decomposed by the acid to produce phenol.
As a result, the compound having a substituent that is decomposed by an acid represented by the general formula (I) has a dissolution rate in an exposed portion that is much higher than that of a compound that produces phenol by the acid, and thus the exposed portion and the unexposed portion Can be increased. Therefore, the exposed portion can be preferentially dissolved and removed,
A high-sensitivity and high-resolution resist for pattern formation can be obtained. In addition, even if a compound that generates a relatively weak acid upon irradiation with light is used as the component (B), the dissolution rate ratio between the exposed and unexposed portions can be increased. Can be widened, and a resist can be prepared according to the application.

When an o-quinonediazide compound is used as the component (B), corrosion of the substrate can be suppressed as compared with a conventional onium salt, and handling is facilitated because of low toxicity. In addition, many conventional chemically amplified resists form an eaves-shaped insoluble layer on the surface of the formed pattern. The resist for pattern formation of the present invention in which the o-quinonediazide compound is blended as the component (B) is less prone to eaves than a conventional chemically amplified resist, and enables formation of a fine pattern having a rectangular cross section. Become.

Further, when a carboxylic acid is blended as the third component, the dissolution rate in an alkali developing solution is increased, and the formation of an insolubilized eaves-like layer above the pattern, which is a problem in a chemically amplified resist, is reduced. A fine pattern having a rectangular cross section can be formed with good reproducibility.

Further, by blending an alkali-soluble resin as the fourth component, the solubility of the exposed portion in an alkali developing solution can be controlled, so that the sensitivity and the resolution can be improved.

According to the resist (2) for pattern formation according to the present invention, the compound (b) in the resist, which generates an acid upon irradiation with light, acts as a dissolution inhibitor in the unexposed area, while the resist is irradiated with light. An acid is generated in the exposed area where the heat treatment is performed. The acid reacts with a compound having a substituent that is decomposed by the acid as the component (a) in the resist to decompose the compound. As a result, the exposed portion can be preferentially dissolved and removed by the development processing after the pattern exposure, so that a resist for pattern formation with high sensitivity and high resolution can be obtained.

The carboxylic acid, which is the component (c) in the resist, increases the dissolution rate in an alkali developing solution. And a fine pattern having a rectangular cross section can be formed.

Further, by blending an alkali-soluble resin as the fourth component, the solubility of the exposed portion in an alkali developing solution can be controlled, so that the sensitivity and the resolution can be improved.

According to the resist (3) for pattern formation according to the present invention, the compound (b1) in the resist, which generates a strong acid upon irradiation with light, acts as a dissolution inhibitor in the unexposed area, while the light irradiation. A strong acid is generated in the exposed area where the exposure is performed. This strong acid decomposes the compound by reacting with a compound having a substituent that is decomposed by the acid as the component (a) in the resist. As a result, the exposed portion can be preferentially dissolved and removed by the development process after the pattern exposure, so that a high-sensitivity and high-resolution resist for pattern formation can be obtained.

The compound (b2) in the resist, which generates a weak acid upon irradiation with light, generates a weak acid upon irradiation with light, but has little or no relation to the decomposition of the component (a). . However, the solubility of the resist is changed to facilitate dissolution in the developer. As a result, by blending the component (b2), the formation of the eaves-shaped insoluble layer at the top of the pattern, which is a problem in the chemically amplified resist, is reduced, and a fine pattern having a rectangular cross section is formed. be able to.

Further, the resists (1) to (3) for forming a pattern according to the present invention can be formed by a process adopted for a conventional positive resist containing naphthoquinonediazide, for example, an alkali treatment for improving the contrast of an image, and a pattern-forming resist. Step baking or dee to improve heat resistance
A pUV cure or the like can be employed, and by doing so, the tolerance of process control such as exposure and development can be increased.

According to the pattern forming method of the present invention, a resist film is formed on a substrate using the pattern forming resists (1) to (3), and pattern exposure is performed, as described above. A compound that generates an acid by light irradiation in each pattern forming resist generates an acid by light irradiation, and the acid reacts with a compound having a substituent that is decomposed by the acid in the resist to decompose the compound. By performing a heat treatment at a predetermined temperature after such pattern exposure, the reaction can proceed not only on the surface of the resist film but also in the thickness direction (substrate side).
As a result, by performing the development process after the heat treatment, not only the surface of the exposed portion but also the region reaching the substrate side can be preferentially dissolved and removed, so that a fine pattern having a rectangular cross section can be formed. In particular, in the case of the pattern forming resist (2), the carboxylic acid as the component (c) increases the dissolution rate in an alkali developer, and in the case of the pattern forming resist (3), the carboxylic acid is the component (b2). A weak acid generated from a compound that generates a weak acid by light irradiation increases the dissolution rate in an alkali developer. As a result, it is possible to reduce the formation of the eaves-shaped hardly-solubilized layer above the pattern, which is a problem in the chemically amplified resist. Therefore, a pattern suitable for an ultra-fine processing step in the manufacture of a semiconductor device can be formed.

Further, according to the pattern forming method of the present invention, a resist film is formed on a substrate using the pattern forming resist (1), and a coating layer made of an acidic water-soluble polymer is formed on the resist film. Is formed, pattern exposure is performed, and heating is performed at a predetermined temperature. The acid generated by the pattern exposure and heating as described above reacts with the compound having a substituent that is decomposed by the acid in the resist, and the reaction is caused not only on the surface of the resist film but also in the thickness direction (substrate side). Proceed until: At this time, by forming the coating layer on the resist film, harmful components in the process atmosphere that hinder the reaction can be blocked. As a result, it is possible to prevent the formation of a hardly-solubilized layer on the surface of the resist film, which is a problem in the chemically amplified resist. The coating layer made of an acidic water-soluble polymer can dissolve even if a hardly-solubilized layer is formed in the resist film in contact with the coating layer. Therefore, an extremely fine pattern having a rectangular cross section can be formed by performing development processing after pattern exposure and heat processing.

[0080]

Embodiments of the present invention will be described below in detail.

(Synthesis Example of Compound Decomposed with Acid) First, 200 g of 50 g of polyvinylphenol (manufactured by Maruzen Petrochemical Co .; PHM-C) was placed in a four-necked flask purged with nitrogen.
Was dissolved in acetone, and 17.63 g of potassium carbonate, 8.48 g of potassium iodide and 24.38 g of tert-butyl bromoacetate were added to the solution, and the mixture was refluxed for 7 hours while stirring. Subsequently, after removing insoluble matter by filtration, acetone was distilled off, and 150 ml
In ethanol. This solution was dropped into 1.5 l of water to precipitate a polymer. The polymer collected by filtration was further washed five times with 300 ml of water, and then air-dried for 12 hours. It was again dissolved in 220 ml of ethanol, reprecipitated and purified by the same operation, and dried in a vacuum dryer at 50 ° C. for 24 hours to obtain 52.0 g of a polymer. From the measurement results of the ¹ H-NMR spectrum,
It was found that 35% of the hydroxy groups in the polyvinyl phenol were changed to tert-butoxycarbonyl methyl ether. Such a polymer (compound having an acid-decomposable substituent) is hereinafter referred to as Ba-35.

Polymers having different hydroxy group substitution rates were synthesized in the same manner as described above. These polymers are shown in Table 9 below.

[0083]

[Table 9]

(Components Constituting Resist) In this example, compounds having a substituent decomposable with an acid other than those in Table 9 are shown in Tables 10 to 15 below, and compounds generating an acid (strong acid) upon irradiation with light are shown in Tables 10 to 15. In Tables 16 and 17 below, compounds generating a weak acid upon irradiation with light are listed in Table 18 below, and additives are listed in Table 19 below.

[0085]

[Table 10]

[0086]

[Table 11]

[0087]

[Table 12]

[0088]

[Table 13]

[0089]

[Table 14]

[0090]

[Table 15]

[0091]

[Table 16]

[0092]

[Table 17]

[0093]

[Table 18]

[0094]

[Table 19]

(Preparation Example 1 of Resist) Compound [Ba-35] having an acid-decomposable substituent described in Table 9 above
2.0 g, 0.44 g of the o-quinonediazide compound [QD-4] (in which the average number of introduced X is 3 in one molecule) described in Table 1 and 2.0 g of polyvinylphenol, were mixed with ethyl cellosolve acetate. Dissolved in 13.8 g;
A resist [RE-1] was prepared by filtration using a 2 μm filter.

(Preparation Examples 2 to 10 of Resists) Compounds having a substituent decomposable with an acid described in Table 9 above, an o-quinonediazide compound described in Tables 1, 3 to 5, and polyvinyl phenol were used. Nine types of resists for pattern formation were blended at the ratios shown in Tables 20 and 21 below, dissolved in solvents of the types and amounts shown in Tables 20 and 21, and filtered using a 0.2 μm filter. Was prepared.
Table 20 below also shows the composition of the resist of Preparation Example 1 described above.

[0097]

[Table 20]

[0098]

[Table 21]

Example 1 The resist [RE-1] described in Table 20 was spin-coated on a 6-inch silicon wafer and prebaked on a hot plate at 90 ° C. for 10 minutes to obtain a thickness of 1. A 0 μm resist film was formed.
Subsequently, after performing a pattern exposure on the resist film with a KrF excimer laser stepper (NA 0.45), 12
Baking was performed on a hot plate at 0 ° C. for 5 minutes. Then
It was immersed in a 1.59% aqueous solution of tetramethylammonium hydroxide (hereinafter abbreviated as TMAH aqueous solution) for 20 seconds, developed, washed with water and dried to form a pattern.

(Examples 2 to 15) A plurality of resists described in Tables 20 and 21 were spin-coated on a 6-inch silicon wafer and prebaked under the conditions shown in Tables 22 and 23 below. Fourteen kinds of resist films having a thickness of 1.0 μm were formed. Subsequently, K is applied to each of the resist films.
After pattern exposure with an rF excimer laser stepper, baking and development were performed under the conditions shown in Tables 22 and 23 below, followed by washing and drying to form 14 types of patterns.

For each of the patterns obtained in Examples 1 to 15, the cross-sectional shape was examined for the width (resolution) of lines and spaces using a scanning electron microscope. Further, the exposure amount at such a resolution was measured. Tables 22 and 23 show these results.
It was also described in.

[0102]

[Table 22]

[0103]

[Table 23]

Example 16 The resist [RE-1] described in Table 20 was spin-coated on a 6-inch silicon wafer, and prebaked on a hot plate at 90 ° C. for 10 minutes to obtain a thickness of 1. A 0 μm resist film was formed. Subsequently, after performing pattern exposure on the resist film with a KrF excimer laser stepper (NA 0.45),
Baking was performed on a hot plate at 120 ° C. for 5 minutes. Subsequently, the film was immersed in a 1.59% TMAH aqueous solution for 45 seconds for development, washed with water, and dried. Thereafter, a step bake was performed in which the temperature was raised from 120 ° C. to 180 ° C. over 10 minutes on a hot plate.

With respect to the pattern obtained in Example 16,
When the cross-sectional shape was observed using a scanning electron microscope,
It was found that the 0.35 μm line and space pattern was resolved. The exposure amount at this time is 40 mJ /
cm ² .

The patterns obtained in Examples 1 and 16 were heated on a hot plate at 180 ° C. for 5 minutes and the shape of the 5 μm pattern was observed using a scanning electron microscope. As a result, it was found that the pattern of Example 1 had a semi-cylindrical shape, but the pattern of Example 16 retained the original shape.

(Example 17) The resist [RE-1] described in Table 20 was spin-coated on a 6-inch silicon wafer, and prebaked on a hot plate at 90 ° C for 10 minutes to obtain a thickness of 1. A 0 μm resist film was formed. Subsequently, after performing pattern exposure on the resist film with a KrF excimer laser stepper (NA 0.45),
Baking was performed on a hot plate at 120 ° C. for 5 minutes. Subsequently, the film was immersed in a 1.59% TMAH aqueous solution for 45 seconds for development, washed with water, and dried. Thereafter, while heating to 110 ° C. on a hot plate under a nitrogen gas atmosphere, light of 290 to 310 nm was irradiated for 2 minutes through a filter of a mercury lamp.

With respect to the pattern obtained in Example 17,
When the cross-sectional shape was observed using a scanning electron microscope,
It was found that the 0.35 μm line and space pattern was resolved. The exposure amount at this time is 40 mJ /
cm ² .

The patterns obtained in Examples 1 and 17 were heated on a hot plate at 180 ° C. for 5 minutes, and the shape of the 5 μm pattern was observed using a scanning electron microscope. As a result, it was found that the pattern of Example 1 had a semi-cylindrical shape, but the pattern of Example 17 had the original shape.

Example 18 The resist [RE-1] described in Table 20 was spin-coated on a 6-inch silicon wafer and prebaked on a hot plate at 90 ° C. for 10 minutes to obtain a thickness of 1. A 0 μm resist film was formed. Subsequently, after performing pattern exposure on the resist film with a KrF excimer laser stepper (NA 0.45),
Baking was performed on a hot plate at 120 ° C. for 5 minutes. Subsequently, the film was developed by immersing it in a 1.59% aqueous solution of TMAH for 15 seconds, washed with water and dried. In addition, 1.59%
Immersed in a TMAH aqueous solution for 15 seconds for development,
Washed and dried.

With respect to the pattern obtained in Example 18,
When the cross-sectional shape was observed using a scanning electron microscope,
It was found that a 0.30 μm line and space pattern was resolved. The exposure amount at this time is 50 mJ /
cm ² .

(Example 19) The resist [RE-1] described in Table 20 was spin-coated on a 6-inch silicon wafer, and prebaked on a hot plate at 90 ° C for 10 minutes to obtain a thickness of 1. A 0 μm resist film was formed. Subsequently, after performing pattern exposure on the resist film with a KrF excimer laser stepper (NA 0.45),
290-31 through a mercury lamp filter while heating to 110 ° C. on a hot plate under a nitrogen gas atmosphere.
Light of 0 nm was irradiated for 5 minutes. 1.59% continued
Immersed in TMAH aqueous solution for 45 seconds and developed,
Washed and dried.

With respect to the pattern obtained in Example 19,
When the cross-sectional shape was observed using a scanning electron microscope,
It was found that a 0.30 μm line and space pattern was resolved. The exposure amount at this time is 55 mJ /
cm ² .

(Preparation Example 11 of Resist) Compound [Ba-20] having an acid-decomposable substituent described in Table 9 above
5.0 g and 0.025 g of the compound [C-1] which generates an acid by light irradiation described in Table 16 above are dissolved in 15.8 g of ethyl cellosolve acetate, and the solution is filtered using a 0.2 μm filter. To prepare a resist [RE-11] for pattern formation.

(Resist Preparation Examples 12 to 19) Table 9
A compound having a substituent capable of decomposing with an acid described in the above, and a compound capable of generating an acid by light irradiation described in the above Table 16,
The alkali-soluble polymer (which may not be blended) was blended in the proportions shown in Tables 24 and 25 below.
Were dissolved in a solvent of the type and amount shown in (1) and filtered using a 0.2 μm filter to prepare eight types of resists for pattern formation. Table 24 below also shows the composition of the resist of Preparation Example 11 described above.

[0116]

[Table 24]

[0117]

[Table 25]

(Example 20) The resist [RE-11] described in Table 24 was spin-coated on a 6-inch silicon wafer, and prebaked on a hot plate at 95 ° C for 90 seconds to obtain a thickness of 1. A 0 μm resist film was formed. Subsequently, an acidic water-soluble polymer solution containing a methyl vinyl ether-maleic anhydride copolymer was spin-coated on the resist film, and the solution was coated on a hot plate at 90 ° C. for 60 minutes.
The coating was baked for seconds to form a coating layer having a thickness of 0.15 μm.
Subsequently, the resist film on which the coating layer was formed was subjected to pattern exposure using a KrF excimer laser stepper (NA 0.45), and then baked on a hot plate at 95 ° C. for 90 seconds. Next, the coating layer was dissolved and removed by washing with pure water, immersed in a 0.14 N aqueous TMAH solution for 90 seconds, developed, washed with water and dried to form a pattern.

(Examples 21 to 24) A plurality of resists described in Table 24 were spin-coated on a 6-inch silicon wafer, and prebaked under the conditions shown in Table 26 below to form a 1.0 μm-thick resist. Four types of resist films were formed. Subsequently, each of the resist films was spin-coated with the same acidic water-soluble polymer solution as in Example 20, and baked on a hot plate at 90 ° C. for 60 seconds to form a coating layer. However, in Examples 21, 23 and 24, a coating layer having a thickness of 0.15 μm was used, and in Example 22, a thickness of 2.15 μm was used.
A coating layer of 0 μm was formed. Subsequently, after performing the pattern exposure, baking, and development processing on the respective resist films on which the coating layer was formed under the conditions shown in Table 26 below,
After washing with water and drying, four types of patterns were formed.

For each of the patterns obtained in Examples 20 to 24, the cross-sectional shape was examined for the width (resolution) of lines and spaces using a scanning electron microscope. Further, the exposure amount at such a resolution was measured. Table 26 also shows these results. In addition, each of the patterns obtained in Examples 20 to 24 had a rectangular cross-sectional shape, and no eaves were formed above the pattern.

[0121]

[Table 26]

(Example 25) A positive resist (trade name; OFPR8, manufactured by Tokyo Ohkasha Co., Ltd.) on a 6-inch silicon wafer
00) was spin-coated and heated on a hot plate at 200 ° C. for 30 minutes to form a positive resist film having a thickness of 2.0 μm. Subsequently, the resist [RE-16] described in Table 25 was spin-coated on the positive resist film to form a resist film having a thickness of 0.5 μm. Subsequently, the same acidic water-soluble polymer solution as in Example 20 was spin-coated on the resist film, and baked on a hot plate at 90 ° C. for 60 seconds to form a coating layer having a thickness of 0.15 μm.

Next, a KrF excimer laser stepper (NA 0.5) was formed on the resist film on which the coating layer was formed.
After performing pattern exposure under the condition of 25 mJ / cm ² by using the method (0), the resultant was baked on a hot plate at 100 ° C. for 180 seconds. Subsequently, the coating layer was dissolved and removed by washing with pure water, immersed in a 2.38% TMAH aqueous solution for 40 seconds, developed, washed with water and dried to form a pattern.

Next, the silicon wafer on which the pattern was formed was placed in a dry etching apparatus (trade name: HiRRIE, manufactured by Tokuda Seisakusho Co., Ltd.), and the silicon wafer exposed from the pattern was exposed to O _{2 at} 100 sccm, a pressure of 6 Pa, and an output of 300 W. The mold resist film was etched.

The cross section of the obtained resist was observed using a scanning electron microscope. As a result, 0.28
It was confirmed that the pattern had a steep pattern having a line and space width of μm.

Example 26 The resist [RE-17] described in Table 25 was spin-coated on a 6-inch silicon wafer and dried on a hot plate at 90 ° C. for 180 hours.
Prebaking was performed for 2 seconds to form a resist film having a thickness of 1.0 μm. Subsequently, the same acidic water-soluble polymer solution as in Example 20 was spin-coated on the resist film,
Bake on a hot plate for 60 seconds to a thickness of 0.15
A μm coating layer was formed. Subsequently, the resist film on which the coating layer was formed was subjected to pattern exposure using a KrF excimer laser stepper (NA 0.45), and then to 120
Baking was performed on a hot plate at 120 ° C. for 120 seconds. Then
After dissolving and removing the coating layer by washing with pure water, 2.38
After immersing in a 30% aqueous solution of TMAH for 30 seconds to develop, it was washed with water and dried to form a pattern.

(Examples 27 to 30) Tables 24 and 25
Were spin-coated on a 6-inch silicon wafer, and prebaked under the conditions shown in Table 27 below to form four types of resist films having a thickness of 1.0 μm. Subsequently, the same acidic water-soluble polymer solution as in Example 20 was spin-coated on each of the resist films, and baked on a hot plate at 90 ° C. for 60 seconds to form a coating layer having a thickness of 0.15 μm. did. Subsequently, each of the resist films on which the coating layer was formed was subjected to pattern exposure, baking, and developing treatments under the conditions shown in Table 27 below, followed by washing with water and drying to form four types of patterns.

For each of the patterns obtained in Examples 26 to 30, the cross-sectional shape was examined for the width (resolution) of lines and spaces by using a scanning electron microscope. Further, the exposure amount at such a resolution was measured. Table 27 also shows these results. In addition, each of the patterns obtained in Examples 26 to 30 had a rectangular cross-sectional shape, and no eaves were formed on the pattern.

[0129]

[Table 27]

(Examples 31 to 34) Compounds having an acid-decomposable substituent shown in Table 28 below, an o-quinonediazide compound, and an alkali-soluble polymer were blended in the proportions shown in Table 28. The resist was dissolved in the amount of ethyl cellosolve acetate shown in No. 28 and filtered using a 0.2 μm filter to prepare four types of resists.

[0131]

[Table 28]

Next, each of the resists was spin-coated on a 6-inch silicon wafer, and prebaked under the conditions shown in Table 29 below to form four types of resist films having a thickness of 1.0 μm. Subsequently, Kr is applied to each of the resist films.
After pattern exposure using an F excimer laser stepper (NA 0.45), baking and development were performed under the conditions shown in Table 29 below, followed by washing with water and drying to form four types of patterns.

For each of the patterns obtained in Examples 31 to 34, the cross-sectional shape was examined for the width (resolution) of lines and spaces by using a scanning electron microscope. Further, the exposure amount at such a resolution was measured. Table 29 also shows these results.

[0134]

[Table 29]

Examples 35 to 39 Compounds having an acid-decomposable substituent shown in Table 30 below, an o-quinonediazide compound, and an alkali-soluble polymer were blended in the proportions shown in Table 30 below. The resist was dissolved in a solvent of the type and amount shown in No. 30 and filtered using a 0.2 μm filter to prepare five types of resists.

[0136]

[Table 30]

Next, each of the resists was spin-coated on a 6-inch silicon wafer, and prebaked under the conditions shown in Table 31 below to form five types of resist films having a thickness of 1.0 μm. Subsequently, Kr is applied to each of the resist films.
After pattern exposure using an F excimer laser stepper (NA 0.45), baking and development were performed under the conditions shown in Table 31 below, followed by washing with water and drying to form five types of patterns.

For each of the patterns obtained in Examples 35 to 39, the cross-sectional shape was examined for the width (resolution) of lines and spaces using a scanning electron microscope. Further, the exposure amount at such a resolution was measured. Table 31 also shows these results.

[0139]

[Table 31]

(Examples 40 to 42) Compounds having a substituent capable of decomposing with an acid shown in Table 32 below, a compound generating an acid by light irradiation, and an alkali-soluble polymer (which may not be blended) are the same. They were blended in the proportions shown in Table 32, dissolved in the amount of ethyl cellosolve acetate shown in Table 32, and filtered using a 0.2 μm filter to prepare three types of photosensitive resin compositions.

[0141]

[Table 32]

Next, each of the resists was spin-coated on a 6-inch silicon wafer, and prebaked under the conditions shown in Table 33 below to form three types of resist films having a thickness of 1.0 μm. Subsequently, Kr is applied to each of the resist films.
After pattern exposure with an F excimer laser stepper (NA 0.45), baking and development were performed under the conditions shown in Table 33 below, followed by washing with water and drying to form three types of patterns.

For each of the patterns obtained in Examples 40 to 42, the cross-sectional shape was examined for the width (resolution) of lines and spaces using a scanning electron microscope. Further, the exposure amount at such a resolution was measured. Table 33 also shows these results.

[0144]

[Table 33]

(Examples 43 to 46) Compounds having an acid-decomposable substituent shown in Table 34 below, compounds generating an acid upon irradiation with light, an alkali-soluble polymer and an additive (the polymer and the additive) Are mixed in the proportions shown in Table 34, dissolved in the amount of ethyl cellosolve acetate shown in Table 34, and filtered using a 0.2 μm filter to obtain four types of resists. Prepared.

[0146]

[Table 34]

Next, each of the resists was spin-coated on a 6-inch silicon wafer, and prebaked under the conditions shown in Table 35 below to form four types of resist films having a thickness of 1.0 μm. Subsequently, Kr is applied to each of the resist films.
After pattern exposure with an F excimer laser stepper (NA 0.45), baking and development were performed under the conditions shown in Table 35 below, followed by washing with water and drying to form four types of patterns.

For each of the patterns obtained in Examples 43 to 46, the cross-sectional shape was examined for the width of lines and spaces (resolution) using a scanning electron microscope. Further, the exposure amount at such a resolution was measured. Table 35 also shows these results.

[0149]

[Table 35]

Example 47 9.5 g of the compound [Ba-25] having a substituent capable of decomposing with an acid described in Table 9 above
And 0.5 g of 1-naphthoquinone-2-diazo-4-sulfonic acid ester of p-cyanophthalate in ethyl-3-
A resist was prepared by dissolving in 40 g of ethoxypropionate and filtering using a 0.2 μm filter.

The resist was spin-coated on a 6-inch silicon wafer and dried on a hot plate at 90 ° C. for 3 hours.
After prebaking for a minute, a resist film (resist film) for pattern formation having a thickness of 1.0 μm was formed. Subsequently, the resist film was subjected to pattern exposure using an i-line stepper (NA 0.50), and baked on a hot plate at 110 ° C. for 2 minutes. Then, 3% aqueous solution of 2.38% TMAH was added.
After immersion for 0 second and development, washing and drying were performed to form a pattern.

When the cross-sectional shape of the obtained pattern was observed using a scanning electron microscope, a pattern having 0.40 μm lines and spaces was resolved at an exposure dose of 50 mJ / cm ² .

Example 48 4.0 g of a compound [Ba-25] having a substituent capable of decomposing with an acid described in Table 9 above
And 4,4′-dihydroxydiphenyl sulfide
0.21 g of naphthoquinone-2-diazo-4-sulfonic acid ester (having one ester per molecule) was dissolved in 12.6 g of ethyl-3-ethoxypropionate. Then, a resist was prepared by filtration. Example 47 using this resist
A pattern was formed in the same manner as described above.

Observation of the cross-sectional shape of the obtained pattern using a scanning electron microscope revealed that a pattern having 0.40 μm lines and spaces was resolved at an exposure dose of 65 mJ / cm ² .

(Example 49) 4.0 g of a compound [Ba-30] having a substituent capable of decomposing with an acid described in Table 9 above
And 0.21 g of 1-naphthoquinone-2-diazo-4-sulfonic acid ester of 2,4-dihydroxyacetophenone (the number of introduced esters is 1.5 per molecule) was dissolved in 12.5 g of ethyl cellosolve acetate. , 0.2μ
The resist was prepared by filtering using a filter of m.

The resist was spin-coated on a 6-inch silicon wafer, and dried on a hot plate at 90 ° C. for 3 hours.
After prebaking for a minute, a resist film (resist film) for pattern formation having a thickness of 1.0 μm was formed. Subsequently, a KrF excimer laser stepper (NA 0.4) is formed on the resist film.
After performing the pattern exposure in 5), it was baked on a hot plate at 120 ° C. for 2 minutes. Then, 2.38% concentration of T
After developing by immersing in MAH aqueous solution for 30 seconds, it was washed with water and dried to form a pattern.

Observation of the cross-sectional shape of the obtained pattern using a scanning electron microscope revealed that a pattern having 0.35 μm lines and spaces was resolved at an exposure dose of 75 mJ / cm ² .

Example 50 4.0 g of a compound [Ba-25] having a substituent capable of decomposing with an acid described in Table 9 above
And 1- of methyl 3,4,5-trihydroxybenzoate
A resist was prepared by dissolving 0.20 g of naphthoquinone-2-diazo-4-sulfonic acid ester (the number of introduced esters was 2 per molecule) in 12.5 g of ethyl lactate and filtering with a 0.2 μm filter. Was prepared. Using this pattern forming resist, a pattern was formed in the same manner as in Example 49.

When the cross-sectional shape of the obtained pattern was observed using a scanning electron microscope, a pattern having 0.35 μm lines and spaces was resolved at an exposure of 85 mJ / cm ² .

Example 51 4.0 g of a compound [Ba-25] having a substituent capable of decomposing with an acid described in Table 9 above
And the o-quinone cyanide compound [Q described in Table 1 above.
D-4] and [QD-5] (each having an ester introduction number of 1
The resist was prepared by dissolving 0.22 g of each (three in the molecule) in 13.5 g of ethyl cellosolve acetate and filtering through a 0.2 μm filter.

The resist was spin-coated on a 6-inch silicon wafer and dried on a hot plate at 90 ° C. for 3 hours.
After pre-baking for 1 minute, a resist film having a thickness of 1.0 μm was formed. Subsequently, an i-line stepper (NA) is formed on the resist film.
0.50), and baked on a hot plate at 110 ° C. for 90 seconds. Then 2.38%
Immersed in a TMAH aqueous solution for 30 seconds and developed,
After washing with water and drying, a pattern was formed.

When the cross-sectional shape of the obtained pattern was observed using a scanning electron microscope, a pattern having 0.35 μm lines and spaces was resolved at an exposure of 100 mJ / cm ² .

(Example 52) 4.0 g of a compound [Ba-35] having a substituent capable of decomposing with an acid described in Table 9 above
0.20 g of diphenyliodonium trifluoromethanesulfonate (Ph ₂ I ⁺ CF ₃ SO ₃ ⁻ );
0.13 g of -hydroxybenzoic acid was dissolved in 13 g of ethyl cellosolve acetate, and the solution was filtered using a 0.2 µm filter to prepare a resist.

The resist was spin-coated on a 6-inch silicon wafer and dried on a hot plate at 90 ° C. for 5 minutes.
After prebaking for a minute, a resist film (resist film) for pattern formation having a thickness of 1.0 μm was formed. Subsequently, a KrF excimer laser stepper (NA0.
After performing pattern exposure in step 42), it was baked on a hot plate at 100 ° C. for 3 minutes. Then, after immersing in a 2.38% concentration TMAH aqueous solution for 30 seconds to develop, washing with water,
Dry to form a pattern.

Observation of the cross-sectional shape of the obtained pattern using a scanning electron microscope revealed that a pattern having 0.35 μm lines and spaces was resolved at an exposure dose of 30 mJ / cm ² .

Further, as shown in FIG.
No eaves-like hardly-solubilized layer was formed on the upper part of the pattern 2 at all, and it was confirmed that the pattern had a good pattern shape.

(Comparative Example) 5 g of [B-12] in Table 14 which is a compound capable of decomposing with an acid and 0.05 g of [C-2] in Table 16 which is a compound which generates an acid upon irradiation with light were used. Dissolve in 15 g of ethyl cellosolve acetate and add 0.2 μ
The resist was prepared by filtering using a filter of m. Using the resist, a pattern was formed in the same manner as in Example 52.

Observation of the cross-sectional shape of the obtained pattern using a scanning electron microscope revealed that a pattern having a line and space of 0.40 μm was resolved at an exposure of 25 mJ / cm ² . However, as shown in FIG. 2, an eaves-shaped hardly-solubilized layer 3 remained above the pattern 2 on the silicon wafer 1.

(Example 53) 3.0 g of a compound [Ba-25] having a substituent capable of decomposing with an acid described in Table 9 above
And o-quinonediazide [QD-
4] (the average number of introduced X is 3 per molecule) 0.44
g, polyvinyl phenol 1.0 g, and acetic acid 0.25
g was dissolved in 13.3 g of ethyl cellosolve acetate, and filtered using a 0.2 μm filter to prepare a resist.

The resist was spin-coated on a 6-inch silicon wafer and dried on a hot plate at 90 ° C. for 3 hours.
After pre-baking for 1 minute, a resist film having a thickness of 1.0 μm was formed. Subsequently, the resist film was subjected to pattern exposure using a KrF excimer laser stepper (NA 0.42), and baked on a hot plate at 120 ° C. for 2 minutes. Next, the film was immersed in a 2.38% aqueous solution of TMAH for 30 seconds for development, washed with water and dried to form a pattern.

When the cross-sectional shape of the obtained pattern was observed using a scanning electron microscope, a pattern having 0.30 μm lines and spaces was resolved at an exposure dose of 50 mJ / cm ² .

(Example 54) A resist similar to that in Example 53 was spin-coated on a 6-inch silicon wafer.
Prebaking was performed on a hot plate at 90 ° C. for 3 minutes to form a 1.0 μm thick resist film. Subsequently, the resist film was subjected to pattern exposure using an i-line stepper having a NA of 0.50 (trade name: 1505i7A, manufactured by Nikon Corporation).
It was baked on a hot plate at 20 ° C. for 1 minute. Then
After immersing in a 2.38% aqueous solution of TMAH for 30 seconds for development, washing and drying were performed to form a pattern.

When the cross-sectional shape of the obtained pattern was observed using a scanning electron microscope, a pattern having lines and spaces of 0.40 μm was resolved. At this time, the light irradiation time was 10 msec.

(Examples 55 to 58) Compounds having an acid-decomposable substituent shown in Table 36 below, a compound capable of generating an acid upon irradiation with light, an alkali-soluble polymer (sometimes not compounded), An acid was mixed in the proportions shown in Table 36, dissolved in the amount of ethyl cellosolve acetate shown in Table 36, and filtered using a 0.2 μm filter to prepare four types of resists.

[0175]

[Table 36]

Then, each of the resists was spin-coated on a 6-inch silicon wafer, and prebaked under the conditions shown in Table 37 below to form four types of resist films having a thickness of 1.0 μm. Subsequently, after pattern exposure was performed on each of the resist films with a KrF excimer laser stepper (NA 0.45), baking and development were performed under the conditions shown in Table 37 below, followed by washing with water and drying to obtain four types of patterns. Formed.

For each of the patterns obtained in Examples 55 to 58, the cross-sectional shape was examined for the minimum line and space width (resolution) resolved using a scanning electron microscope. Further, the exposure amount at such a resolution was measured. Table 37 also shows these results.

[0178]

[Table 37]

(Examples 59 to 62) Compounds having an acid-decomposable substituent shown in Table 38 below, compounds generating an acid upon irradiation with light, an alkali-soluble polymer (sometimes not compounded), An acid was mixed in the proportions shown in Table 38, dissolved in solvents of the types and amounts shown in Table 38, and filtered using a 0.2 μm filter to prepare four types of photosensitive resin compositions. .

[0180]

[Table 38]

Next, each of the resists was spin-coated on a 6-inch silicon wafer, and prebaked under the conditions shown in Table 39 below to form four types of resist films having a thickness of 1.0 μm. Subsequently, after pattern exposure was performed on each of the resist films with a KrF excimer laser stepper (NA 0.45), baking and development were performed under the conditions shown in Table 39 below, followed by washing with water and drying to obtain four types of patterns. Formed.

For each of the patterns obtained in Examples 59 to 62, the cross-sectional shape was examined for the minimum line and space width (resolution) resolved using a scanning electron microscope. Further, the exposure amount at such a resolution was measured. Table 39 also shows these results.

[0183]

[Table 39]

Each of the patterns formed by Examples 55 to 62 described above had a rectangular cross section, and no eaves were formed above the pattern.

(Preparation Example 21 of Resist) Compound [Ba-20] having an acid-decomposable substituent described in Table 9 above
5.0 g, 0.025 g of the compound [C-1] that generates a strong acid upon irradiation with light described in Table 16 and Table 18
Compounds that generate a weak acid upon irradiation with light [D-
2] 0.56 g was dissolved in 16.7 g of ethyl lactate,
A resist [RE-21] was prepared by filtration using a 0.2 μm filter.

(Resist Preparation Examples 22 to 30) Table 9
, A compound that generates a strong acid by light irradiation described in Table 16 above, a compound that generates a weak acid by light irradiation described in Table 18 above, and an alkali-soluble polymer (when not mixed). Are mixed in the proportions shown in Tables 40 and 41 below, dissolved in solvents of the types and amounts shown in Tables 40 and 41, and filtered through a 0.2 μm filter to obtain 9 types. Was prepared. Table 40 below also shows the composition of the resist [RE-21] of Preparation Example 21.

[0187]

[Table 40]

[0188]

[Table 41]

(Example 63) The resist [RE-21] described in Table 40 was spin-coated on a 6-inch silicon wafer, and prebaked on a hot plate at 95 ° C for 90 seconds to form a film having a thickness of 1. A 0 μm resist film was formed. Subsequently, after performing pattern exposure on the resist film with a KrF excimer laser stepper (NA 0.45),
Baking was performed on a hot plate at 95 ° C. for 90 seconds. Next, the film was immersed in a 1.19% aqueous solution of TMAH for 90 seconds for development, washed with water and dried to form a pattern.

(Examples 64-71) Tables 40 and 41
Are coated on a 6-inch silicon wafer by spin coating, respectively.
Pre-baking was performed under the conditions shown in (1) to form eight types of resist films having a thickness of 1.0 μm. Subsequently, pattern exposure, baking, and baking were performed on the respective resist films under the conditions shown in Tables 42 and 43 below.
After the development treatment, the film was washed with water and dried to form eight patterns.

For each of the patterns obtained in Examples 63 to 71, the cross-sectional shape was examined for the width (resolution) of lines and spaces using a scanning electron microscope. Further, the sensitivity (exposure amount) at this resolution was measured. Table 4 shows these results.
2. Also shown in Table 43.

[0192]

[Table 42]

[0193]

[Table 43]

Example 72 Positive resist (trade name; OFPR8, manufactured by Tokyo Ohkasha Co., Ltd.) on a 6-inch silicon wafer
00) was spin-coated and heated on a hot plate at 200 ° C. for 30 minutes to form a positive resist film having a thickness of 2.0 μm. Subsequently, a resist [RE-30] described in Table 41 was spin-coated on the positive resist film to form a resist film having a thickness of 0.5 μm. Subsequently, an i-line stepper (NA 0.5
After pattern exposure was performed under the condition of 45 mJ / cm ² using the method (0), baking was performed on a hot plate at 100 ° C. for 180 seconds. After that, 4% aqueous solution of 2.38% TMAH was added.
After immersion for 0 second and development, washing and drying were performed to form a pattern.

Next, the silicon wafer on which the pattern was formed was set in a dry etching apparatus (trade name: HiRRIE, manufactured by Tokuda Seisakusho Co., Ltd.), and the positive electrode exposed from the pattern under the conditions of O ₂ 100 sccm, pressure 6 Pa, and output 300 W was used. The mold resist film was etched.

The cross section of the obtained pattern was observed using a scanning electron microscope. As a result, 0.35
It was confirmed that the pattern had a steep pattern having a line and space width of μm.

[0197]

As described above in detail, according to the present invention, it is possible to provide a resist for pattern formation having high sensitivity and high resolution to ultraviolet rays (particularly deep UV) and ionizing radiation. Further, according to the present invention, it is possible to provide a method capable of forming a fine pattern with a rectangular cross section, and it is possible to provide a remarkable effect such that the method can be effectively used in an ultrafine processing step in the manufacture of a semiconductor device.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a pattern formed on a silicon wafer according to Example 52.

FIG. 2 is a cross-sectional view showing a pattern formed on a silicon wafer according to a comparative example.

[Explanation of symbols]

 1: silicon wafer, 2: pattern, 3: hardly soluble layer.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 2, 2001 (2001.7.2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

Patent application title: Pattern forming resist and pattern forming method

[Claims]

Embedded image Here, in the formula (I), R ¹ is an alkyl group or a benzyl group, m is 0 or a positive number of 1 or more, and n is a positive number.

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern forming resist and a pattern forming method used for fine processing of a semiconductor device, particularly, a large-scale semiconductor integrated circuit (LSI).

[0002]

2. Description of the Related Art In the process of manufacturing a semiconductor device such as an LSI,
Fine processing technology by photolithography is employed. Such a technique, for example, a photoresist film is formed on a substrate such as a silicon single crystal wafer by a spin coating method or the like, and after pattern exposure of the resist film, development, rinsing or the like is performed to form a resist pattern, Further, a method of forming fine lines and windows by etching the exposed substrate using the resist pattern as an etching mask.

In the manufacture of the above-mentioned LSI, finer processing technology is required with the increase in integration of the LSI. In response to such demands, attempts have been made to shorten the wavelength of an exposure light source. Specifically, a lithography technique using deep UV light such as a KrF excimer laser or an ArF excimer laser as a light source is known.

However, since the conventional resist has a large absorption for light of a short wavelength, the light sufficiently reaches a portion distant from the surface of the resist film, for example, a portion on the substrate side covered with the resist film. Can not do. For this reason, the cross-sectional shape of the developed resist pattern becomes an inverted triangle. As a result, when the resist pattern is used as an etching mask for a substrate or the like, there has been a problem that the pattern cannot be accurately transferred to the substrate or the like.

As a resist that solves such a problem, a chemically amplified resist has been proposed. The chemically amplified resist includes a compound that generates a strong acid upon irradiation with light (photoacid generator) and a compound that decomposes a hydrophobic group by an acid to change the group into a hydrophilic substance. Specifically, H. It
o, C, G, Wilson, J .; M. J. Franch
et, U.S.A. S. Patent 4,491,628 (1
No. 985) discloses a positive resist containing a polymer obtained by blocking a hydroxyl group of poly (p-hydroxystyrene) with a butoxycarbonyl group and an onium salt which is a compound capable of generating an acid upon irradiation with light. Also, M. J. O'B
Rien, J. et al. V. Crivello, SPIE Vo
1,920, Advances in Resist
Technology and Processin
g, p42, (1988), m-cresol novolak resin and naphthalene-2-carboxylic acid-tert.
-Positive resists containing butyl esters and triphenylsulfonium salts have been published. Furthermore, H. It
o, SPIE Vol, 920, Advances i
n Resist Technology and P
processing, p33, (1988)
A positive resist containing 2,2-bis (4-tert-butoxycarbonyloxyphenyl) propane, polyphthalaldehyde and an onium salt has been disclosed.

[0006] Since the photoacid generator acts as a catalyst,
Reacts efficiently even in small amounts. Therefore, when the resist film is irradiated with light, the reaction sufficiently proceeds even in the interior where the light is hard to reach compared to the surface. As a result, a resist pattern having a steep side surface can be formed by the development processing.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to have high sensitivity and high resolution to ultraviolet rays and ionizing radiation,
An object of the present invention is to provide a resist for pattern formation suitable for an ultrafine processing step in the manufacture of a semiconductor device.

Another object of the present invention is to provide a method capable of forming a fine pattern having a rectangular cross section.

[0009]

The resist for pattern formation according to the present invention comprises (a) a compound having a substituent which is decomposed by an acid represented by the following general formula (I):
(B1) a compound that generates a strong acid upon irradiation with light;
2) a compound that generates a weak acid upon irradiation with light.

[0010]

Embedded image

In the formula (I), R ¹ is an alkyl group or a benzyl group, m is 0 or a positive number of 1 or more, and n is a positive number.

The pattern forming method according to the present invention comprises the steps of (a)
For forming a pattern comprising a compound having a substituent decomposed by an acid represented by the general formula (I), (b1) a compound generating a strong acid upon irradiation with light, and (b2) a compound generating a weak acid upon irradiation with light. A resist is applied to a substrate, subjected to desired pattern exposure, heated, and then developed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a resist for pattern formation according to the present invention will be described in detail.

The resist for pattern formation according to the present invention comprises:
(A) a compound having a substituent which is decomposed by an acid represented by the following general formula (I), (b1) a compound which generates a strong acid upon irradiation with light, and (b2) a compound which generates a weak acid upon irradiation with light And a compound to be used.

[0015]

Embedded image

In the formula (I), R ¹ is an alkyl group or a benzyl group, m is 0 or a positive number of 1 or more, and n is a positive number.

The alkyl group introduced into the above-mentioned general formula (I) includes, for example, methyl, ethyl, n-propyl, is
o-propyl, n-butyl, tert-butyl, iso
-Butyl, sec-butyl and the like can be used. In particular, tert-butyl is preferred.

N / (m + n) in the general formula (I)
Is 0.03 to 1, more preferably 0.05 to 0.1.
It is desirably in the range of 70. The reason for this is that n
If the value of / (m + n) is less than 0.03, the dissolution rate difference between the exposed and unexposed areas may be small, and the resolution may be reduced. This is because there is a possibility that the pattern may be formed or the pattern surface may be roughened.

The compound represented by formula (I) desirably has a molecular weight of 1,000 or more from the viewpoint of improving heat resistance.

The compound as the component (b1) is irradiated with light.
The strong acid, for example, pK (K is the ionization constant of the electrolyte) is 3
It is a compound that generates an acid that is less than. This compound
Various known compounds and mixtures can be used.
You. For example, diazonium salts, phosphonium salts, sulfo
Salt, iodonium salt CF_ThreeSO_Three ^-, P-CH
_ThreePhSO_Three ^-, P-NO_TwoPhSO_Three ^-(However, P
h is a salt such as a phenyl group), an organic halogen compound, ortho
Quinone-diazidosulfonyl chloride or sulfonic acid
Esters and the like can be mentioned. The organic halogenation
The compound is a compound that forms hydrohalic acid,
Such compounds are disclosed in U.S. Pat. No. 3,515,552, U.S. Pat.
No. 3,536,489, U.S. Pat. No. 3,779,778 and West.
German Patent Publication No. 2243621
Is included. Generates acid by other light irradiation as described above
Compounds disclosed in JP-A-54-74728 and JP-A-55-74728.
-24113, JP-A-55-77742, JP-A-6
0-3626, JP-A-60-138439, JP-A-60-13839
56-17345 and JP-A-50-36209
It is shown.

Specific examples of such compounds include:
Di (p-tert-butylphenyl) iodonium trifluoromethanesulfonate, diphenyliodonium trifluoromethanesulfonate, benzoin tosylate, orthonitrobenzyl paratoluenesulfonate, triphenylsulfonium trifluoromethanesulfonate, tri (tert-butylphenyl) sulfonium trifluoromethanesulfonate, Benzenediazonium paratoluenesulfonate, 4- (di-n-propylamino) -bensonium 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-quinoline, 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-anthracy-1)
-Yl) -4,6-bis-trichloromethyl-S-triazine, 2- (phenant-9-yl) -4,6-bis-trichloromethyl-S-triazine, o-naphthoquinonediazide-4-sulfonic acid chloride Etc. Examples of the sulfonic acid ester include naphthoquinonediazide-4-sulfonic acid ester, p-toluenesulfonic acid-o-nitrobenzyl ester, and p-toluenesulfonic acid-2,6.
-Dinitrobenzyl ester and the like.

As the component (b1), a compound which generates a strong acid upon irradiation with light, it is particularly preferable to use an o-quinonediazide compound. The o-quinonediazide compound is not particularly limited, but may be o-quinonediazide-.
Esters of 4-sulfonic acid and phenolic compounds are preferred. An ester of o-quinonediazide-4-sulfonic acid and a phenol compound can be obtained by reacting o-quinonediazidesulfonic acid chloride with a phenol compound according to a conventional method. Examples of the o-quinonediazidesulfonic acid chloride include, for example, 1
-Benzophenone-2-diazo-4-sulfonic acid chloride, 1-naphthoquinone-2-diazo-4-sulfonic acid chloride and the like can be used. Examples of the phenol compound 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, p-
Dimethyl hydroxybenzylidenemalonate, gintolyl p-hydroxybenzylidenemalonate, cyanophenol, nitrophenol, nitrosophenol, hydroxyacetophenone, methyl trihydroxybenzoate, polyvinylphenol, novolak resin and the like can be used. Such o-quinonediazide compounds are specifically exemplified in Tables 1 to 5 below.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

[0026]

[Table 4]

[0027]

[Table 5]

Among the o-quinonediazide compounds, 1-naphthoquinone-2-diazo-4-sulfonic acid ester is particularly preferred. Such esters are described in J. Grun
Wald, C, Gal, S, Eidelman, SPI
E Vol, 1262, Advances in Re
sist Technology and Process
As disclosed in ssingVII, p444 (1990), it is known that carboxylic acid and sulfonic acid, which is an acid stronger than carboxylic acid, are generated by light irradiation, and the catalyst has a large catalytic action and is particularly effective.

It is desirable that the compound (b1) be contained in an amount of 0.1 to 20% by weight, more preferably 0.5 to 10% by weight, based on all solid components of the resist for pattern formation. This is for the following reason.
When the compounding amount of the compound is less than 0.1% by weight, it becomes difficult to obtain sufficient photosensitive characteristics. On the other hand, if the compounding amount of the compound exceeds 20% by weight, it may be difficult to form a uniform resist film, or residues may be generated during removal after development or etching.

The compound (b2) has a weak acid such as pK (K is the ionization constant of the electrolyte) of 3 when irradiated with light.
It is a compound that generates the acid described above. Examples of the compound include 1,2-naphthoquinonediazide-5-sulfonic acid ester, 5-diazomeldrum acid and derivatives thereof, and diazodimedone derivatives.

It is desirable that the compound (b2) be contained in an amount of 1 to 30% by weight, more preferably 5 to 20% by weight, based on all solid components of the resist for pattern formation.
This is for the following reason. If the compounding amount of the compound is less than 1% by weight, it becomes difficult to suppress the formation of a hardly soluble layer on the resist surface. On the other hand, if the compounding amount of the compound exceeds 30% by weight, it may be difficult to form a uniform resist film, or residues may be generated during removal after development or etching.

The resist for pattern formation allows carboxylic acid to be contained as a fourth component in addition to the components (a), (b1) and (b2). Such a carboxylic acid is blended to increase the dissolution rate in an alkaline aqueous solution and to reduce eaves generated on the pattern surface. The carboxylic acid is not particularly limited as long as it is uniformly mixed in the resist for pattern formation. Specifically, formic acid, acetic acid, propionic acid, butyric acid, 2-methylpropanoic acid, valeric acid, isovaleric acid, α-methylbutyric acid, trimethylacetic acid, hexanoic acid, 4-methylpentanoic acid, 2-methylbutanoic acid, 2, 2-dimethylbutanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, eiconic acid, docosanoic acid, hexacosanoic acid, triaconic acid, oxalic acid , Malonic acid, succinic acid, glutanic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, ascorbic acid, tridecanoic acid, methylmalonic acid, ethylmalonic acid, dimethylmalonic acid, methylsuccinic acid, 2,2- Dimethyl succinic acid, 2,3-dimethyl succinic acid, tetramethyl succinic acid, 1,2,2 - propane tricarboxylic acid, 1,2,3
-Propenetricarboxylic acid, 2,3-dimethylbutane-
1,2,3-trifluorocarboxylic acid, fluoroacetic acid, trifluoroacetic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, bromoacetic acid, iodoacetic acid, 2-chloropropionic acid, 3-chloropropionic acid, 2-bromopropionic acid, 3 -Bromopropionic acid, 2-iodopropionic acid, 2,3-dichloropropionic acid, chlorosuccinic acid,
Bromosuccinic acid, 2,3-dibromosuccinic acid, hydroxyacetic acid, lactic acid, 2-hydroxybutyric acid, 2-hydroxy-
2-methylpropanoic acid, 2-hydroxy-4-methylpentanoic acid, 3-hydroxy-3-pentanecarboxylic acid,
3-hydroxypropionic acid, 10-hydroxyoctanedecanoic acid, 3,3,3-trichloro-2-hydroxypropionic acid, 2- (lactoyloxy) propionic acid, glyceric acid, 8,9-dihydroxyoctadecanoic acid, tartronic acid , Malic acid, acetoxysuccinic acid, 2
-Hydroxy-2-methylbutanedioic acid, 3-hydroxypentanedioic acid, tartaric acid, ethyl d-bitartrate, tetrahydroxysuccinic acid, citric acid, 1,2-dihydroxy-1,1,2-ethane-tricarboxylic acid, ethoxy Acetic acid, 2,2′-oxydiacetic acid, 2,3-epoxypropionic acid, pyruvic acid, 2-oxobutyric acid, acetoacetic acid, 4
-Oxovaleric acid 9,10-dioxooctadecanoic acid, mesooxalic acid, oxaloacetic acid, 3-oxoglutanic acid,
-Oxoheptanedioic acid, benzoic acid, toluic acid, ethylbenzoic acid, p-isopropylbenzoic acid, 2,3-dimethylbenzoic acid, 2,4-dimethylbenzoic acid, 2,5-dimethylbenzoic acid, 3,5- Dimethylbenzoic acid, 2,4,5
-Trimethylbenzoic acid, phthalic acid, isophthalic acid, terephthalic acid, 5-methylisophthalic acid, 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, 1,2,
3,4-benzenetetracarboxylic acid, 1,2,3,5-
Benzenetetracarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, benzenepentacarboxylic acid, benzenehexacarboxylic acid, fluorobenzoic acid, chlorobenzoic acid, dichlorobenzoic acid, trichlorobenzoic acid, bromobenzoic acid, dibromobenzoic acid Acid, iodobenzoic acid, chlorophthalic acid, dichlorophthalic acid, tetrachlorophthalic acid, nitrosobenzoic acid, o-nitrobenzoic acid, p-nitrobenzoic acid, 2,4-dinitrobenzoic acid, 2,4,6-trinitrobenzoic acid Acid, 3-nitrobenzoic acid, 5-nitroisophthalic acid, 2-nitroterephthalic acid, p-hydroxybenzoic acid, salicylic acid, 5-chlorosalicylic acid, 3,5-dichlorosalicylic acid, 3-nitrosalicylic acid, 3,5-dinitro Salicylic acid, 2,4-dihydroxybenzoic acid,
3,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,4,5
-Trihydroxybenzoic acid, 2,3,4-trihydroxybenzoic acid, 2,4,6-trihydroxybenzoic acid, 6
-Hydroxy-2-toluic acid, 2-hydroxy-3-
Toluic acid, 6-hydroxy-3-toluic acid, 2-hydroxy-4-toluic acid, 2-hydroxy-3-isopropyl-6-methylbenzoic acid, 4-hydroxy-5
Isopropyl-2-methylbenzoic acid, 2,4-dihydroxy-6-methylbenzoic acid, 2-hydroxyphthalic acid,
4-hydroxyisophthalic acid, 2-hydroxyterephthalic acid, 3,4-dihydroxyphthalic acid, 2,5-dihydroxyphthalic acid, 2-hydroxy-1,3,5-benzenetricarboxylic acid, (hydroxymethyl) benzoic acid,
(1-hydroxy-1-methylethyl) benzoic acid, anisic acid, vanillic acid, 3-hydroxy-4-methoxybenzoic acid, 3,4-dimethoxybenzoic acid, 3,4-methylenedioxybenzoic acid, 3,4 2,5-trimethoxybenzoic acid, 3,4-dimethoxyphthalic acid, o-phenoxybenzoic acid, o-acetoxybenzoic acid, 3-o-galloyl gallic acid, p-acetylbenzoic acid, p-benzoylbenzoic acid, 4,4 '-Carbonyldibenzoic acid, p-acetamidobenzoic acid, o-benzoamidobenzoic acid, phthalanilic acid, phenylacetic acid, 2-phenylpropionic acid, 3-phenylpropionic acid, 4-phenylbutyric acid, p-hydroxyphenylacetic acid, 2, 5-dihydroxyphenylacetic acid,
3- (o-hydroxyphenyl) propionic acid, 2,3
-Dibromo-phenylpropionic acid, α-hydroxyphenylacetic acid, 2-hydroxy-2-phenylpropionic acid, 2-hydroxy-3-phenylpropionic acid, 3-
Hydroxy-2-phenylpropionic acid, 3-hydroxy-3-phenylpropionic acid, 2,3-epoxy-3
-Phenylpropionic acid, phenylsuccinic acid, o-carboxyphenylacetic acid, 1,2-benzenediacetic acid, phenylglyoxylic acid, o-carboxyglyoxylic acid,
Phenylpyruvic acid, benzoylacetic acid, 3-benzoylpropionic acid, phenoxyacetic acid, benzoyloxyacetic acid, 2-benzoyloxypropionic acid, succinanilic acid, carbanilic acid, oxanilic acid, o-carboxyoxanilic acid, 4-biphenylcarboxylic acid, , 2'-biphenyldicarboxylic acid, benzylbenzoic acid, diphenylacetic acid, α-hydroxydiphenylacetic acid, o-benzhydrinbenzoic acid, phenolphthalein, triphenylacetic acid, uvic acid, 5-methyl-2-furancarboxylic acid,
-Furancarboxylic acid, furic acid, paraconic acid, terenic acid, terpenylic acid, aconic acid, coumaric acid, comonic acid,
Comenic acid, kelidonic acid, meconic acid and the like can be mentioned.

The carboxylic acid is desirably contained at 0.5 to 20% by weight, more preferably 1 to 10% by weight, in all solid components of the resist for pattern formation. This is for the following reason. When the amount of the carboxylic acid is less than 0.5% by weight, it becomes difficult to improve the pattern shape after formation, exposure and development of a resist film. On the other hand, if the amount of the carboxylic acid is more than 20% by weight, the difference in dissolution rate between the exposed and unexposed portions becomes small during the formation of the resist film and the development after the exposure, which may lower the resolution.

The resist for forming a pattern is allowed to further contain an alkali-soluble polymer as a fifth component in addition to the components (a), (b1) and (b2).

As the alkali-soluble polymer, a resin containing an aryl group or a carboxy group into which a hydroxy group has been introduced is desirable. Specifically, phenol novolak resin, cresol novolak resin, xylesol novolak resin, vinyl phenol resin, isopropenyl phenol resin, copolymers of vinyl phenol with acrylic acid, methacrylic acid derivative, acrylonitrile, styrene derivative, etc. Copolymer of propenylphenol with acrylic acid, methacrylic acid derivative, acrylonitrile, styrene derivative, etc., copolymer of styrene derivative with acrylic resin, methacrylic resin, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, acrylonitrile, etc. Or a compound containing silicon in these polymers. However, from the viewpoint of resistance during dry etching, a resin containing an aromatic ring is preferable, and examples thereof include a phenol novolak resin and a cresol novolak resin. Specific alkali-soluble polymers are listed in Tables 6, 7, and 8 below. Further, quinone in the phenol resin generated by the oxidation may be reduced to improve the transparency.

[0036]

[Table 6]

[0037]

[Table 7]

[0038]

[Table 8]

When the total amount of the compound having a substituent which is decomposed by an acid and the alkali-soluble polymer is 100 parts by weight, the alkali-soluble polymer is 90 parts by weight or less, more preferably 80 parts by weight or less. It is desirable to do. The reason for this is that if the blending amount of the alkali-soluble polymer exceeds 90 parts by weight, the difference in dissolution rate between the exposed and unexposed parts is small, and the resolution may be reduced.

Further, the resist for pattern formation comprises the components (a), (b1) and (b2), the carboxylic acid,
In addition to the alkali-soluble polymer, a sensitizer, a dye, a surfactant, and a dissolution inhibitor may be contained as necessary.

The resist for pattern formation is prepared by dissolving the components (a), (b1), and (b2), and the carboxylic acid, alkali-soluble polymer, and the like blended as necessary, in an organic solvent, and filtering. It is prepared by Examples of the organic solvent include ketone solvents such as cyclohexanone, acetone, methyl ethyl ketone, and methyl isobutyl ketone, methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, and butyl cellosolve acetate.
And ester solvents such as ethyl acetate, butyl acetate, isoamyl acetate, ethyl lactate and methyl lactate, N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide and the like. These solvents may be used alone or in the form of a mixture. However, these may contain an appropriate amount of an aliphatic alcohol such as xylene, toluene or isopropyl alcohol.

Next, a pattern forming method according to the present invention will be described.

First, the resist for pattern formation is coated on a substrate by a spin coating method or a dipping method.
The resist film is formed by drying at 0 ° C. or lower, preferably 70 to 120 ° C. As the substrate used here, for example, a silicon wafer, a silicon wafer having steps on which various insulating films and electrodes, wirings are formed on the surface, a blank mask,
Examples include a III-V compound semiconductor wafer such as GaAs or AlGaAs.

Next, pattern exposure is performed by selectively irradiating the resist film with ultraviolet rays (particularly deep UV) or ionizing radiation through a mask having a desired pattern. At this time, in the resist film made of the resist for pattern formation, a compound which generates a strong acid and a weak acid by light irradiation, which are the components (b1) and (b2) therein, generates a strong acid and a weak acid by light irradiation. The strong acid therein reacts with a compound having a substituent which is decomposed by the acid as the component (A) in the resist film. As the ultraviolet light, for example, an excimer laser such as KrF, ArF, XeF, or XeCl, or an i-line, an h-line, or a g-line of a mercury lamp can be used. Examples of the ionizing radiation include an electron beam, X
Lines or the like can be used. In the pattern exposure step, pattern exposure may be performed directly on the resist film by scanning the electron beam without using the mask.

Next, the resist film after the pattern exposure is heated at, for example, 70 to 160 ° C., preferably 80 to 150 ° C. At this time, the reaction between the strong acid generated in the resist film and the compound having a substituent decomposed by the acid in the resist film is promoted. The reason for limiting the temperature in the heating step is as follows. When the temperature is lower than 70 ° C., the reaction between the acid from the compound that generates an acid upon irradiation with light and the compound having a substituent that is decomposed by the acid cannot be sufficiently performed. On the other hand, if the temperature exceeds 160 ° C., the exposed portion and the unexposed portion of the resist film are decomposed or cured.

Next, the resist film after the heat treatment is developed with, for example, an aqueous alkaline solution to form a desired resist pattern. Examples of the alkaline aqueous solution used here include an inorganic alkaline aqueous solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, sodium silicate, and sodium metasilicate; an organic aqueous solution such as an aqueous tetramethylammonium hydroxide solution and an aqueous trimethylhydroxyethylammonium hydroxide solution. Alkaline aqueous solution,
Alternatively, those to which an alcohol, a surfactant, or the like is added can be used. Then, after the developer is washed away with water, the substrate is dried.

In the pattern forming method according to the present invention, after the development processing, the substrate is gradually heated to carry out a step bake for crosslinking the resin component of the resist pattern, or to irradiate deep UV while heating to cure the resin of the resist pattern. Allow deep UV curing to crosslink the components. By performing such processing, the heat resistance of the pattern can be improved.

Further, in the pattern forming method according to the present invention, the resist film is allowed to be immersed in a low-concentration aqueous alkaline solution before or after the exposure and then subjected to the subsequent development processing. By performing such a process, the dissolution rate of the unexposed portion of the resist film can be reduced, and the contrast of the relief image can be improved. In the treatment, the resist film may be immersed in an amine such as trimethylamine, triethanolamine, hexamethylsilazane or the like instead of the alkaline aqueous solution, or may be exposed to the vapor of these amines. After exposing the substrate to an aqueous alkaline solution, heat treatment may be performed as necessary.

Further, in the pattern forming method according to the present invention, it is allowed to perform fog exposure by irradiating the entire surface of the resist film with heating while heating after the pattern exposure. By performing such a process, the dissolving speed of the unexposed portion of the resist film can be reduced to improve the resolution.

[0050]

According to the resist for pattern formation according to the present invention, the compound (b1) in the resist, which is a compound which generates a strong acid upon irradiation with light, acts as a dissolution inhibitor in unexposed areas, and is irradiated with light. A strong acid is generated in the exposed part.
The compound having a substituent which is decomposed by the acid represented by the general formula (I), which is the component (a) in the resist, is decomposed by the strong acid generated from the component (b1) to generate a carboxylic acid. For this reason, it becomes very easy to dissolve in a developing solution composed of an alkaline aqueous solution. On the other hand, conventionally used compounds having a substituent that can be decomposed by many acids are decomposed by the acid to produce phenol. As a result, the compound having a substituent that is decomposed by an acid represented by the general formula (I) has a dissolution rate in an exposed portion that is much higher than that of a compound that produces phenol by the acid, and thus the exposed portion and the unexposed portion Can be increased.
Therefore, since the exposed portion can be preferentially dissolved and removed, a resist for pattern formation with high sensitivity and high resolution can be obtained.

In many conventional chemically amplified resists, an oversolubilized insoluble layer is formed on the surface of the formed pattern. The resist for pattern formation of the present invention, in which an o-quinonediazide-4-sulfonic acid ester compound is particularly blended as the component (b1), is less prone to eaves than a conventional chemically amplified resist, and has a rectangular cross section. A fine pattern can be formed.

Further, the compound (b2) in the resist, which generates a weak acid upon irradiation with light, generates a weak acid upon irradiation with light, but has little or no relation to the decomposition of the component (a). . However, the solubility of the resist is changed to facilitate dissolution in the developer. As a result, by blending the component (b2), the formation of the eaves-shaped insoluble layer at the top of the pattern, which is a problem in the chemically amplified resist, is reduced, and a fine pattern having a rectangular cross section is formed. be able to.

Further, the resist for forming a pattern according to the present invention is a process used for a conventional positive resist containing naphthoquinonediazide, for example, an alkali treatment for improving image contrast, and a heat treatment for improving heat resistance of a pattern. Step baking, deep UV curing, and the like can be employed, and by performing these steps, the tolerance of process management such as exposure and development can be increased.

Further, if a carboxylic acid is blended as the fourth component, the dissolution rate in an alkali developing solution is increased, and the formation of an eaves-shaped insolubilized layer on the upper portion of the pattern, which is a problem in a chemically amplified resist, is reduced. A fine pattern having a rectangular cross section can be formed with good reproducibility.

Further, by blending an alkali-soluble resin as the fifth component, the solubility of the exposed portion in an alkali developing solution can be controlled, so that sensitivity and resolution can be improved.

According to the method for forming a pattern according to the present invention, a resist film is formed on a substrate by using the resist for forming a pattern, and is subjected to pattern exposure. Upon irradiation, the component (b1) generates a strong acid, and the strong acid reacts with a compound having a substituent that is decomposed by the acid represented by the general formula (I) in the resist to decompose the compound to form a carboxylic acid. Occurs. By performing a heat treatment at a predetermined temperature after such pattern exposure, the reaction can proceed not only on the surface of the resist film but also in the thickness direction (substrate side). As a result, by performing the development process after the heat treatment, not only the surface of the exposed portion but also the region reaching the substrate side can be preferentially dissolved and removed, so that a fine pattern having a rectangular cross section can be formed. In particular, the weak acid generated from the compound that generates a weak acid upon irradiation with light, which is the component (b2), increases the dissolution rate in an alkali developer. As a result, it is possible to reduce the formation of the eaves-shaped hardly-solubilized layer above the pattern, which is a problem in the chemically amplified resist. Therefore, a pattern suitable for an ultra-fine processing step in the manufacture of a semiconductor device can be formed.

[0057]

Embodiments of the present invention will be described below in detail.

(Synthesis Example of Compound Decomposed by Acid) First, 200 g of 50 g of polyvinyl phenol (manufactured by Maruzen Petrochemical Co .; PHM-C) was placed in a nitrogen-substituted four-necked flask.
Was dissolved in acetone, and 17.63 g of potassium carbonate, 8.48 g of potassium iodide and 24.38 g of tert-butyl bromoacetate were added to the solution, and the mixture was refluxed for 7 hours while stirring. Subsequently, after removing insoluble matter by filtration, acetone was distilled off, and 150 ml
In ethanol. This solution was dropped into 1.5 l of water to precipitate a polymer. The polymer collected by filtration was further washed five times with 300 ml of water, and then air-dried for 12 hours. It was again dissolved in 220 ml of ethanol, reprecipitated and purified by the same operation, and dried in a vacuum dryer at 50 ° C. for 24 hours to obtain 52.0 g of a polymer. From the measurement results of the ¹ H-NMR spectrum,
It was found that 35% of the hydroxy groups in the polyvinyl phenol were changed to tert-butoxycarbonyl methyl ether. Such a polymer (compound having an acid-decomposable substituent) is hereinafter referred to as Ba-35.

Polymers having different hydroxy group substitution rates were synthesized in the same manner as described above. These polymers are shown in Table 9 below.

[0060]

[Table 9]

(Components Constituting Resist) In this example, compounds which generate a strong acid upon irradiation with light are shown in Table 1 below.
Compounds that generate a weak acid upon irradiation with light are listed in Table 11 below.

[0062]

[Table 10]

[0063]

[Table 11]

(Preparation Example 1 of Resist) Compound [Ba-20] having an acid-decomposable substituent described in Table 9 above
5.0 g, 0.025 g of the compound [C-1] that generates a strong acid upon irradiation with light described in Table 10 above, and Table 11 above.
Compounds that generate a weak acid upon irradiation with light [D-
2] 0.56 g was dissolved in 16.7 g of ethyl lactate,
A resist [RE-1] was prepared by filtration using a 0.2 μm filter.

(Resist Preparation Examples 2 to 9) Compounds decomposed by an acid described in Table 9 above, compounds capable of generating a strong acid by light irradiation described in Table 10 above, and light irradiation described in Table 11 above Table 1 shows a compound which generates a weak acid by the treatment and an alkali-soluble polymer (which may not be blended).
2. Compounded at the ratios shown in Table 13, dissolved in solvents of the types and amounts shown in Tables 12 and 13, and filtered using a 0.2 μm filter to prepare eight types of resists. Table 12 below shows the resist [R
The composition of E-1] is also described.

[0066]

[Table 12]

[0067]

[Table 13]

Example 1 The resist [RE-1] described in Table 12 was spin-coated on a 6-inch silicon wafer and prebaked on a 95 ° C. hot plate for 90 seconds to obtain a thickness of 1. A 0 μm resist film was formed.
Subsequently, after performing a pattern exposure on the resist film by using a KrF excimer laser stepper (NA 0.45), 95%
Baking was performed on a hot plate at 90 ° C. for 90 seconds. Then
After immersing in a 1.19% aqueous solution of TMAH for 90 seconds for development, it was washed with water and dried to form a pattern.

(Examples 2 to 8) A plurality of resists described in Tables 12 and 13 were spin-coated on a 6-inch silicon wafer, and prebaked under the conditions shown in Tables 14 and 15 below. Eight types of resist films having a thickness of 1.0 μm were formed. Subsequently, each of the resist films was subjected to pattern exposure, baking, and developing treatments under the conditions shown in Tables 20 and 21 below, followed by washing with water and drying to form seven types of patterns.

For each of the patterns obtained in Examples 1 to 8, the cross-sectional shape was examined for the width (resolution) of lines and spaces using a scanning electron microscope. Further, the sensitivity (exposure amount) at this resolution was measured. Table 14 shows the results.
Also shown in Table 15.

[0071]

[Table 14]

[0072]

[Table 15]

Example 9 A positive resist (trade name: OFPR80, manufactured by Tokyo Ohkasha Co., Ltd.) was formed on a 6-inch silicon wafer.
0) was spin-coated and heated on a hot plate at 200 ° C. for 30 minutes to form a positive resist film having a thickness of 2.0 μm. Subsequently, the resist [RE-9] described in Table 13 was spin-coated on the positive resist film to form a resist film having a thickness of 0.5 μm. Subsequently, the resist film was subjected to pattern exposure using an i-line stepper (NA 0.50) under the condition of 45 mJ / cm ² , and baked on a hot plate at 100 ° C. for 180 seconds. Thereafter, the film was immersed in a 2.38% aqueous solution of TMAH for 40 seconds for development, washed with water and dried to form a pattern.

Next, the silicon wafer on which the pattern was formed was set in a dry etching apparatus (trade name: HiRRIE, manufactured by Tokuda Seisakusho Co., Ltd.), and the positive electrode exposed from the pattern under the conditions of O ₂ 100 sccm, pressure 6 Pa, and output 300 W was used. The mold resist film was etched.

The cross-sectional shape of the obtained pattern was observed using a scanning electron microscope. As a result, 0.35
It was confirmed that the pattern had a steep pattern having a line and space width of μm.

Further, as shown in FIG.
No eaves-like hardly-solubilized layer was formed on the upper part of the pattern 2 at all, and it was confirmed that the pattern had a good pattern shape.

(Comparative Example) 5 g of [B-12] of the structural formula shown below, which is a compound decomposable by an acid, and [C-2] 0 of Table 10 which is a compound which generates an acid upon irradiation with light. .
05 g was dissolved in 15 g of ethyl cellosolve acetate, and filtered using a 0.2 μm filter to prepare a resist.

The resist was spin-coated on a 6-inch silicon wafer and dried on a 90 ° C. hot plate.
After prebaking for a minute, a resist film (resist film) for pattern formation having a thickness of 1.0 μm was formed. Subsequently, a KrF excimer laser stepper (NA0.
After performing pattern exposure in step 42), it was baked on a hot plate at 100 ° C. for 3 minutes. Then, after immersing in a 2.38% concentration TMAH aqueous solution for 30 seconds to develop, washing with water,
Dry to form a pattern.

When the cross-sectional shape of the obtained pattern was observed using a scanning electron microscope, it was found that the pattern having lines and spaces of 0.40 μm was resolved at an exposure dose of 25 mJ / cm ² . However, as shown in FIG. 2, an eaves-shaped hardly-solubilized layer 3 remained above the pattern 2 on the silicon wafer 1.

[0080]

Embedded image

[0081]

As described above in detail, according to the present invention, it is possible to provide a resist for pattern formation having high sensitivity and high resolution to ultraviolet rays (particularly deep UV) and ionizing radiation. Further, according to the present invention, it is possible to provide a method capable of forming a fine pattern with a rectangular cross section, and it is possible to provide a remarkable effect such that the method can be effectively used in an ultrafine processing step in the manufacture of a semiconductor device.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a pattern formed on a silicon wafer according to a tenth embodiment.

FIG. 2 is a cross-sectional view showing a pattern formed on a silicon wafer according to a comparative example.

[Description of Signs] 1 ... silicon wafer, 2 ... pattern, 3 ... hardly soluble layer.

Continuing from the front page (72) Inventor Hirokazu Niki 1 Toshiba-cho, Komukai-shi, Saitama-ku, Kawasaki-shi, Kanagawa Prefecture Inside of Toshiba Research Institute, Ltd. Inside Toshiba Research Institute, Inc. (72) Inventor Naohiko Chisato 1 at Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Inside Toshiba Research Institute Inc. (72) Inventor Shuji Hayase Toshiba, Koyuki-ku, Kawasaki-shi, Kanagawa No. 1 town Toshiba Research Institute, Inc. (72) Inventor Kazuo Sato No. 1 Komukai Toshiba Research Center, Koyuki-ku, Kawasaki-shi, Kanagawa Prefecture No. 1, Muko Toshiba, Toshiba Research Institute, Inc.

Claims (2)

[Claims] 1. A method comprising: (a) a compound having a substituent capable of being decomposed by an acid; (b1) a compound generating a strong acid upon irradiation with light; and (b2) a compound generating a weak acid upon irradiation with light. Resist for pattern formation. 2. A pattern forming method, comprising applying the pattern forming resist according to claim 1 to a substrate, performing desired pattern exposure, heating, and developing.