JP2000147770A - Positive radiation-sensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive radiation-sensitive resin composition superior in sensitivity and resolution and good in environmental resistance. SOLUTION: The positive radiation-sensitive resin composition comprises (A) an alkali-soluble resin having phenolic hydroxyl groups or at least one part of the above hydroxyl groups being protected with an acid-decomposable protective group, (B) a compound having a partial structure decomposable by an action of an acid and capable of producing a group for giving alkali- solubility upon decomposition and (C) a compound to be decomposed by activated rays or radiation resulting in generating an acid and the compound (B) can be embodied by a compound having, as the partial structure to be decomposed by an acid and to give the alkali solubility, a partial structure of an optionally substituted >=7C alkyl carbonate group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a positive-working radiation-sensitive composition. More specifically, the present invention relates to a positive radiation-sensitive resin composition which is excellent in pattern shape, resolution and environmental resistance and is suitable for a positive resist for producing a semiconductor integrated circuit.

[0002]

2. Description of the Related Art The wave of high integration and high density of semiconductor integrated circuits is remarkably fast, and especially, DRAM (Dynami)
c Random Access Memory) has already started mass production of 16 Mbits,
It is said that the production of those having a storage capacity of 4 Mbits and 256 Mbits will start. 0.50 for 16Mbit
μm line width is 64 Mbit, 256 MbitDR
In AM, the design rules of 0.30 μm and 0.25 μm are applied, and development of a photoresist corresponding to such quarter-micron lithography is urgently required. X-ray lithography, electron beam lithography, and far-ultraviolet lithography represented by a KrF excimer laser are used as lithography corresponding to quarter micron or smaller semiconductor device design rules.

Incidentally, photoresists containing an alkali-soluble novolak resin and a naphthoquinonediazide-based photosensitizer have been known for lithography of g-rays and i-rays. However, exposure using X-rays, electron beams or far ultraviolet rays has been known. In this case, a good pattern profile cannot be obtained, and the resolution is poor. Therefore, a novolak naphthoquinonediazide-based material is unsuitable for lithography smaller than quarter micron. Also, a resist material having higher sensitivity is required in terms of throughput.

[0004] As a high-performance resist free of such disadvantages, H.I. A resist called a chemically amplified type proposed by Ito et al. Has been studied (Polm. En).
g. Sci. , 23, 1012 (1983)). This is a resin that has a photoacid generator that generates an acid upon irradiation with actinic rays or radiation, and a resin that has a functional group that is easily desorbed by the acid, and that changes the dissolution rate in an alkaline developer before and after the desorption of the functional group. Is a positive photosensitive composition.

[0005] As a problem peculiar to such a chemically amplified resist, there is a problem of so-called environmental resistance. In other words, a chemically amplified resist uses the catalytic action of a small amount of acid generated by exposure to light, and is affected by acidic or basic substances that enter the resist film from the surrounding environment, resulting in a change in sensitivity or pattern shape. Is likely to deteriorate.

As a method for solving such a problem,
A method of applying a protective film on a resist film, a method of using a chemical filter that adsorbs basic substances in the environment,
There is known a method of adding a basic substance such as an amine to a resist. However, each of these methods also has advantages and disadvantages.For example, when a protective film is used as an upper layer of a resist film, if a weakly acidic protective film is used to reduce the influence of a basic substance in the air, the surface of the resist film is reduced. However, there is a problem that the surface of the protective film becomes alkali-soluble due to the acid of the protective film and surface roughness occurs.

For example, Japanese Patent Application Laid-Open No. 6-51519 discloses a combination of an alkali-soluble resin and a low-molecular acid-decomposable dissolution-inhibiting compound, which is described as having an effect of improving sensitivity, resolution and pattern profile. ing. This publication describes a specific example in which a tert-butoxycarbonyloxy group is used as an acid-decomposable protecting group. However, in our study, the combination of a low-molecular dissolution inhibitor containing a tert-butoxycarbonyloxy group as an acid-decomposable protecting group with an alkali-soluble resin such as polyvinylphenol,
The result was that the edge roughness of the resist pattern was large.

[0008] The edge roughness referred to here is:
When the resist pattern is observed from above using a scanning electron microscope, irregularities are observed at the edges of the resist, and the resist line width is not constant. When such a phenomenon occurs, a variation in processing dimensions occurs at the time of processing a substrate using a resist as a mask, which is a problem.
This edge roughness is noticeable when the compatibility between the resist base resin and other additive components is poor,
As a result of our examination, we understood.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a positive type resist which maintains resist performance such as sensitivity and depth of focus, improves environmental resistance so as not to be affected by an upper protective film, and has a small edge roughness. An object of the present invention is to provide a radiation-sensitive resin composition.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, a specific component in a chemically amplified photoresist, namely, decomposition by the action of an acid, alkali By using a compound having an alkyl carbonate group having a bulky group having a large number of carbon atoms as a partial structure capable of generating a group that imparts solubility, sensitivity, the influence of the upper protective film while maintaining performance such as depth of focus can be reduced. The present inventors have found that it is possible to improve the environmental resistance so as not to suffer from such damage, to suppress the roughness of the resist film surface, and to reduce the edge roughness.

That is, the gist of the present invention is (A) a phenolic hydroxyl group-containing alkali-soluble resin or a resin in which at least a part of the hydroxyl group is protected by an acid-decomposable protecting group,
Positive radiation-sensitive resin containing (B) a compound having a partial structure capable of generating a group which becomes alkali-soluble by being decomposed by the action of an acid, and (C) a compound which is decomposed by an actinic ray or radiation to generate an acid. In the composition, component (B)
Is a positive-type radiation-sensitive resin composition characterized by having an alkyl carbonate group having 7 or more carbon atoms which may be substituted as a partial structure capable of forming a group imparting alkali solubility. Hereinafter, the present invention will be described in detail.

In the present invention, as the alkali-soluble resin containing a phenolic hydroxyl group as the component (A), any resin which becomes alkali-soluble at the time of development, elutes in an alkali developing solution, and has a uniform resist film forming ability can be used. For example, polyhydroxystyrenes such as a novolak resin, a resin obtained by polymerization of hydroxystyrene alone or a copolymer of hydroxystyrene and various vinyl monomers can be used. here,
Polyhydroxystyrenes may be homopolymerized or copolymerized as long as the polymer has a structure derived from hydroxystyrene as a partial structure, and those having a substituent on a benzene ring or other portions. Including. In the case of the novolak resin, phenol, o-cresol, m-cresol, p-cresol, resorcinol, pyrogallol, xylenol and the like can be used as the phenol component, and formaldehyde, acetaldehyde, benzaldehyde, acetone and the like as the aldehyde or ketone component. Can be used. As the vinyl monomer copolymerized with hydroxystyrene, a compound containing an ethylenically unsaturated double bond such as acrylic acid, vinyl alcohol, or a derivative thereof can be used.

In the case of a resist for exposure to far ultraviolet rays, in particular, in exposure to KrF or ArF excimer laser light, polyhydroxystyrenes can be preferably used. The novolak resin has a large absorbance at the wavelength of the KrF excimer laser beam, and the exposure intensity at the bottom portion of the resist film is weak, so that the resist shape tends to be trapezoidal.

When the phenolic hydroxyl group-containing alkali-soluble resin is a polyhydroxystyrene, specifically,
o-hydroxystyrene, m-hydroxystyrene, p
A radical polymerization initiator comprising one or more hydroxystyrenes such as -hydroxystyrene, 2- (o-hydroxyphenyl) propylene, 2- (m-hydroxyphenyl) propylene and 2- (p-hydroxyphenyl) propylene; A resin polymerized in the presence of an anionic polymerization initiator or a cationic polymerization initiator is used. Also,
After the polymerization, a resin subjected to hydrogenation to reduce the absorbance of the resin may be used. Further, resins in which at least a part of the hydroxyl groups of these phenolic hydroxyl group-containing alkali-soluble resins are protected with an acid-decomposable protecting group can also be used.
Examples of the derivative of the compound having an ethylenically unsaturated double bond copolymerized with hydroxystyrene include a compound in which vinyl hydrogen of the compound is substituted with an alkyl group, and a hydrogen atom of a hydroxyl group or a carboxylic acid group is an alkyl group. And those substituted with an alkoxyalkyl group or an alkoxycarbonyl group.

The acid-decomposable protecting group is one which is eliminated by an acid generated from the component (C) at the time of exposure at room temperature or by heating after exposure (post-exposure bake) to regenerate a phenolic hydroxyl group. Although there is no particular limitation as long as it is present, for example, methoxymethoxy, 1-methoxyethoxy, 1-methoxypropyloxy, 1-methoxybutyloxy, 1-ethoxyethoxy, 1-ethoxypropyloxy, 1-ethoxybutyloxy Group, 1
-(N-butoxy) ethoxy group, 1- (iso-butoxy) ethoxy group, 1- (sec-butoxy) ethoxy group, 1- (tert-butoxy) ethoxy group, 1- (cyclohexyloxy) ethoxy group, tetrahydrofuranyl Acetal groups such as oxy group and tetrahydropyranyloxy group Ketal groups such as -methoxy-1-methylethoxy group,
Methoxycarbonyloxy group, ethoxycarbonyloxy group, n-propyloxycarbonyloxy group, iso
-Propyloxycarbonyloxy group, n-butoxycarbonyloxy group, sec-butoxycarbonyloxy group, iso-butoxycarbonyloxy group, t-butoxycarbonyloxy group, menthyloxycarbonyloxy group, etc. In the detailed description, the acid-decomposable protecting group includes an oxygen atom derived from a phenolic hydroxyl group. Of these, a group represented by the following general formula (I) is particularly preferred.

[0016]

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(Wherein R ¹ and R ² independently represent a hydrogen atom, an optionally substituted alkyl group or an optionally substituted alkoxy group, and R ³ represents an optionally substituted alkyl group R ¹ and R ³ may combine to form a ring.) The alkyl and alkoxy groups represented by R ^{1 to} R ³ preferably have 1 to 1 carbon atoms.
More preferably, it is 1 to 10.

As the component (A), these may be used alone, or a plurality of them may be used as a mixture. In the resin in which the phenolic hydroxyl group is protected by an acid-decomposable protecting group, the acid-decomposable protecting group may be used alone or in combination of two or more. A copolymer having an acid-decomposable protecting group may be used.

As the component (A), when a resin in which the phenolic hydroxyl group is protected with an acid-decomposable protecting group is used, the difference in solubility between the exposed and unexposed portions of the resist becomes larger, This is preferable because the resist shape and resolution after development are improved. The protection ratio of the phenolic hydroxyl group of the alkali-soluble resin by the acid-decomposable protecting group is not particularly limited, but is preferably 5 to 60%, and particularly preferably 10 to 50%. If the protection ratio is lower than the above description, the residual film ratio of the unexposed portion of the resist film tends to decrease, and the resolution tends to decrease. On the other hand, if the protection ratio is too large, the developer may be repelled at the time of development, and development may not be possible.

The weight average molecular weight Mw of the resin used as the component (A) can be used as long as it can form a resist film and can be developed with an alkali developing solution after exposure. Permeation chromatography measurement), usually from 3,000 to 100,000, preferably from 4,000 to 5
6,000 or less, more preferably 6,000 or more,
000 or less are used.

If the weight-average molecular weight of the resin is larger than this range, the solubility of the exposed portion in an alkali developing solution becomes small, and there is a fear that a good resist pattern cannot be obtained. If the weight-average molecular weight of the resin is smaller than this range, a good resist coating may not be obtained. As a method for adjusting the phenolic hydroxyl group-containing alkali-soluble resin to the above range, there are a fractional precipitation method, a fractional dissolution method, a column fractionation method, an ultracentrifugation method and the like, and any of these methods may be used. Further, the molecular weight distribution Mw /
Mn is preferably 1 or more and 1.5 or less from the viewpoint of resolution.

Component (B) (hereinafter referred to as dissolution inhibitor)
Has the effect of decreasing the alkali dissolution rate of the component (A) by adding it to the composition, and improving the solubility of the resist film at room temperature or under heating after exposure, thereby improving the dissolution contrast. A group that is decomposed by the action of an acid to impart alkali solubility, more specifically, a compound having a partial structure that generates a hydroxyl group. In the present invention, the partial structure is a bulky hydrocarbon group, specifically, It must be an alkyl carbonate group having 7 or more carbon atoms which may be substituted. That is, by having a carbonate group having a bulky group having more carbon atoms than the conventionally known t-butoxycarbonyloxy group, particularly the edge roughness is improved. The alkyl carbonate group preferably has 7 to 21 carbon atoms, and more preferably 9 to 17 carbon atoms. In addition, the carbon number includes carbon of carbonyl. Further, from the viewpoint of a bulky group, a secondary or tertiary alkyl carbonate group and a cyclic alkyl carbonate group are preferred. The component (B) is not particularly limited as long as it satisfies the above requirements. Specifically, alcohols such as ethanol, propanol, butanol, cyclohexanol, 1,4-cyclohexanediol, ethylene glycol, propylene glycol, and glycerin; Phenols such as cresol, resorcinol, pyrogallol, o-hydroxybenzophenone, m-hydroxybenzophenone, p-hydroxybenzophenone, 4,4′-dihydroxybenzophenone, 2,3
4-trihydroxybenzophenone, 2,3,4,4 '
-Tetrahydroxybenzophenone, 2,3,4
Hydroxybenzophenones such as 2 ', 4'-pentahydroxybenzophenone or JP-A-6-5151
No. 9, at least a part of the hydroxyl group of a hydroxyl group-containing compound such as a polynuclear phenol obtained by condensing a phenol with an aldehyde or a ketone, etc. The compounds protected by the above alkyl carbonate groups are exemplified.

Of these, at least a part of the hydroxyl group of the polynuclear phenol obtained by condensing the phenol with an aldehyde or ketone is protected by an optionally substituted alkylcarbonate group having 7 or more carbon atoms. Compounds are preferred. More specifically, phenols mean a phenol having 1 to 3 valences which may have a substituent such as an alkyl group. Examples of the aldehyde include substituents such as formaldehyde, acetaldehyde, an alkyl group and / or a hydroxyl group. The C ₁ -C ₁₅ aldehyde such as benzaldehyde which may be possessed as a ketone is a C ₃ -C ₁₅ ketone such as acetophenone which may have a substituent such as acetone, an alkyl group and / or a hydroxyl group. No. As the carbonate group, it is preferable to have a bulky alkyl group, and therefore a branched alkyl group or a cyclic alkyl group is preferable, and more specifically, the following general formula (II)
Or those having the structure represented by (III) are more preferable.

[0024]

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(Wherein, R ⁴ , R ⁵ and R ⁶ independently represent a hydrogen atom or a linear or branched alkyl group which may be substituted, and are bonded to each other to form a ring. Well,
n represents a natural number of 5 or more and 15 or less. )

[0026]

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(R ⁷ , R ⁸ and R ⁹ independently represent an optionally substituted linear or branched alkyl group.
The total number of carbon atoms of ⁷ , R ⁸ and R ⁹ is 5 or more. When R ^{4 to} R ^{9 in the} above formulas (II) and (III) are alkyl groups, the number of carbon atoms is usually 1 to 10, preferably 1 to 6.
R ⁹ in the formula (III) is preferably a hydrogen atom. Specifically, a cyclohexyloxycarbonyloxy group,
A menthyloxycarbonyloxy group represented by the following structural formula (II-
Alicyclic alkyloxycarbonyloxy groups represented by 1), (II-2), (II-3), and (II-4), and a group further having a substituent in their structures, 2- ( n-hexyl) oxycarbonyloxy group, 3,3-dimethyl-2
-Butoxycarbonyloxy group, 3-methyl-2-pentyloxycarbonyloxy group, 2,4-dimethyl-3
Secondary alkyloxycarbonyloxy groups such as -pentyloxycarbonyloxy group and 2,6-dimethyl-4-heptyloxycarbonyloxy group, and groups having further substituents in their structures.

[0028]

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The component (B) is distinguished from the resin of the component (A), and the preferred molecular weight range of the dissolution inhibitor is 200 or more and less than 3,000. When the molecular weight is smaller than this range, a sufficient dissolution inhibiting effect cannot be obtained, and when the molecular weight is larger than this range, the solubility after exposure is reduced, and the resist pattern shape tends to be deteriorated.

In the case of a compound in which at least a part of the hydroxyl group of a polynuclear phenol is protected by the above-mentioned carbonate group, the higher the protection ratio of the phenolic hydroxyl group in one molecule is, the higher the dissolution inhibiting effect becomes. % Or more and 100% or less are preferable. More preferably 60
% To 100%, more preferably 80% to 100%
% Or less.

The amount of the dissolution inhibitor added depends on the amount of the resin component (A).
The dissolution inhibitor is used in a proportion of 1 to 50 parts by weight, preferably 5 to 40 parts by weight, per 100 parts by weight. When the amount of the dissolution inhibitor is used in this range, a sufficient change in the dissolution rate between the exposed portion and the unexposed portion can be obtained, and a particularly good resist pattern can be obtained. If the amount of the dissolution inhibitor is too large, the undissolved dissolution inhibitor after exposure may not dissolve in the developing solution and a residue may remain between the resist patterns.

The component (C) (hereinafter referred to as a photoacid generator) used in the present invention is not particularly limited as long as it generates an acid by actinic rays or radiation used for exposure. Known ones can be used,
Specifically, for example, tris (trichloromethyl) -s
-Triazine, tris (tribromomethyl) -s-triazine, tris (dibromomethyl) -s-triazine,
Halogen-containing s-triazine derivatives such as 2,4-bis (tribromomethyl) -6-p-methoxyphenyl-s-triazine, 1,2,3,4-tetrabromobutane,
Halogen-substituted paraffinic hydrocarbons such as 1,1,2,2-tetrabromoethane, carbon tetrabromide and iodoform;
Halogen-substituted cycloparaffinic hydrocarbons such as hexabromocyclohexane, hexachlorocyclohexane, and hexabromocyclododecane; halogen-containing benzene derivatives such as bis (trichloromethyl) benzene and bis (tribromomethyl) benzene; tribromomethylphenylsulfone; trichloromethyl Phenyl sulfone,
Halogen-containing sulfone compounds such as 2,3-dibromosulfolane, halogen-containing isocyanurate derivatives such as tris (2,3-dibromopropyl) isocyanurate, triphenylsulfonium chloride, triphenylsulfonium methanesulfonate, and triphenylsulfonium trifluoromethylsulfonate , Triphenylsulfonium, p-toluenesulfonate, sulfonium salts such as triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroarsenate, triphenylsulfonium hexafluorophosphonate, diphenyliodonium trifluoromethylsulfonate, diphenyliodonium p-toluenesulfonate , Diphenyliodonium tetrafluoroborate, diphenyl Iodonium salts such as iodonium hexafluoroarsenate, diphenyliodonium hexafluorophosphonate, methyl p-toluenesulfonate, ethyl p-toluenesulfonate, butyl p-toluenesulfonate, phenyl p-toluenesulfonate, 1,2,3- Tri (p-toluenesulfonyloxy) benzene, p-toluenesulfonic acid benzoin ester, methyl methanesulfonate, ethyl methanesulfonate, butyl methanesulfonate, 1,2,3-tri (methanesulfonyloxy) benzene, methanesulfonic acid Phenyl, methanesulfonic acid benzoin ester, methyl trifluoromethanesulfonate, ethyl trifluoromethanesulfonate, butyl trifluoromethanesulfonate,
Sulfonates such as 1,2,3-tri (trifluoromethanesulfonyloxy) benzene, phenyl trifluoromethanesulfonate and benzoin trifluoromethanesulfonate, disulfones such as diphenyldisulfone, and carbonyls such as phenylcarbonylphenylsulfonyldiazomethane Bissulfonylmethanes such as sulfonyldiazomethanes, bis (phenylsulfonyl) methane and bis (cyclohexylsulfonyl) methane; bissulfonyldiazomethanes such as bis (phenylsulfonyl) diazomethane and bis (cyclohexylsulfonyl) diazomethane; o-nitrobenzyl-p O-nitrobenzyl esters such as toluenesulfonate; sulfones such as N, N′-di (phenylsulfonyl) hydrazide Examples include hydrazides, iminosulfonates such as phthaliminotrifluoromethylsulfonate, phthalimino p-toluenesulfonate, and phthaliminocamphorsulfonate. Among these, compounds that generate sulfonic acid after exposure are suitably used, and among them, bisphenylsulfonyldiazomethanes represented by the following general formula (IV) are particularly preferable.

[0033]

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(Provided that R ⁹ and R ¹⁰ independently represent a linear, branched or cyclic alkyl group which may be substituted, an allyl group which may be substituted, an aralkyl group which may be substituted; In the radiation-sensitive composition of the present invention, the resin component (A)
The photoacid generator is used in an amount of 0.001 to 30 parts by weight, preferably 0.05 to 20 parts by weight, based on 100 parts by weight. If the amount of the photoacid generator is less than this range, the sensitivity is inferior. If the amount is larger than this range, the transparency of the resist film due to the photoacid generator may cause the resist pattern to become trapezoidal, causing a reduction in resolution. is there.

Additives can be added to the resist of the present invention, and examples of the additives include organic carboxylic acids, organic bases, surfactants, and light absorbing agents. The organic carboxylic acid is effective in suppressing a decrease in resist performance due to invasion of a basic substance from the environment. Particularly, when used in combination with the dissolution inhibitor (B), edge roughness is further improved, and This is preferable because it has the effect of suppressing the bottom portion of the resist on the basic substrate from having a skirted shape.

Specific examples of the organic carboxylic acids which can be used in the present invention include formic acid, acetic acid, propionic acid, n-butyric acid, iso-butyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, acrylic acid Aliphatic carboxylic acids such as methacrylic acid, maleic acid and fumaric acid, ketocarboxylic acids such as pyruvic acid, benzoic acid, salicylic acid, o-hydroxybenzoic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 2,4- Commercially available as aromatic carboxylic acids such as dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, phthalic acid, terephthalic acid, and isophthalic acid, or trade name SAX (manufactured by Mitsui Toatsu Chemicals). For example, a polymer containing a structural unit of an aromatic carboxylic acid can be used.

The amount of the organic carboxylic acid added is 0.00 0.00 parts by weight of the organic carboxylic acid per 100 parts by weight of the resin component (A).
It is used in an amount of from 0.01 to 10 parts by weight, preferably from 0.001 to 5 parts by weight. When the organic carboxylic acid is used in an amount in the above range, an effect of preventing diffusion of a basic substance which enters from the environment to the exposed portion is obtained, and a favorable resist pattern is obtained, which is preferable. However, an excessive amount is not preferable because the residual film ratio of the unexposed portion of the resist decreases.

The organic base prevents the acid generated from the photoacid generator from diffusing into the unexposed area, and specific examples thereof include alkylamines, arylamines, pyridines, and pyridinium salts. Compounds disclosed in JP-A-5-127369, JP-A-5-232706, JP-A-7-92678, JP-A-9-179300, and JP-A-9-325496 can be used.

The amount of the organic base added depends on the amount of the resin component (A) 10
0.0001 to 5 parts by weight of an organic base relative to 0 parts by weight,
Preferably, it is used in a ratio of 0.001 to 2 parts by weight.
When the organic base is used in an amount in the above range, an effect of preventing sufficient diffusion of the acid to the unexposed portion is obtained, and a favorable resist pattern is obtained, which is preferable. However, an excessive amount is not preferable because the sensitivity of the resist is lowered. The surfactant is added for the purpose of improving the coating properties of the radiation-sensitive resin composition, improving the film thickness uniformity during spin coating, and improving the developability of the radiation-sensitive resin composition.

Examples of the surfactant which can be used for this purpose include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, and polyoxyethylene nonyl phenyl ether. Oxyethylene glycol laurate, polyoxyethylene glycol distearate,
F-top EF301, EF303, EF352 (manufactured by Tochem Products), Megafac F170, F17
1, F172, F173 (Dai Nippon Ink Co., Ltd.), Florade FC430, FC431, FC170C (Sumitomo 3M
Asahi Guard AG710, Surflon S-38
2, SC-101, SC-102, SC-103, SC
-104, SC-105, SC-106 (made by Asahi Glass Co., Ltd.), KP341 (made by Shin-Etsu Chemical Co., Ltd.), Polyflow No.
75, no. 95 (manufactured by Kyoeisha Yushi Kagaku Kogyo) and the like. These surfactants can be used alone or as a mixture of two or more kinds. Usually, the surfactant is used in a proportion of 0.01 part by weight to 3 parts by weight based on 100 parts by weight of the resin component (A). Is done.

When an image of a resist is formed on a substrate having a high reflectance, such as aluminum, a light absorbing agent can be added to prevent deterioration of the resist pattern shape due to reflection of exposure light from the substrate. Examples of the light absorbing agent used for such a purpose include naphthoquinonediazide compounds, benzophenones, and compounds containing a condensed aromatic ring such as naphthalene and anthracene.

Usually, the radiation-sensitive resin composition of the present invention is used by dissolving each of the above components in an appropriate solvent. The solvent is not particularly limited as long as it has a sufficient solubility in the photoacid generator, the additive, and the resin and gives good coating properties, and ketones such as 2-hexanone and cyclohexanone System solvents, cellosolve solvents such as methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, diethyl oxalate, ethyl pyruvate, ethyl-2-hydroxybutyrate, ethyl acetoacetate, butyl acetate, amyl acetate, ethyl butyrate Butyl butyrate, methyl lactate, ethyl lactate, ester solvents such as methyl 3-methoxypropionate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether Propylene glycol solvents such as teracetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol dimethyl ether, cyclohexanone, methyl amyl ketone, ketone solvents such as 2-heptanone, or a mixed solvent thereof, or further Those to which an aromatic hydrocarbon is added are exemplified. The use ratio of the solvent is preferably in the range of 1 to 20 times by weight based on the total amount of solids in the radiation-sensitive resin composition.

When a resist pattern is formed on a semiconductor substrate using the radiation-sensitive resin composition of the present invention, the radiation-sensitive resin composition of the present invention dissolved in a solvent as described above is usually applied to the semiconductor substrate. And then subjected to pre-baking, pattern transfer by exposure, post-exposure baking (post exposure bake; PEB), and development steps to be used as a photoresist. Semiconductor substrates are those that are usually used as semiconductor manufacturing substrates,
For example, a silicon substrate or a gallium arsenide substrate may be used.

A spin coater is usually used for coating.
For exposure, light of 436 nm and 365 nm of a high pressure mercury lamp,
254 nm of a low-pressure mercury lamp, or 157 nm, 193 nm, 222 nm, 2
Light of 48 nm, X-rays, electron beams and the like are preferably used.
Light at the time of exposure may be broad instead of monochromatic light. Exposure by a super-resolution exposure technique such as a phase shift method and an annular illumination is also applicable.

The developer of the radiation-sensitive resin composition of the present invention includes inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, and n-propyl. Primary amines such as amines, secondary amines such as diethylamine and di-n-propylamine, tertiary amines such as triethylamine, N, N-diethylmethylamine, tetramethylammonium hydroxide, trimethylhydroxyl A quaternary ammonium salt such as ethylammonium hydroxide, or a quaternary ammonium salt to which an alcohol, a surfactant or the like is added can be used. The radiation-sensitive resin composition of the present invention has a super LS
For general IC production, mask production,
It is also useful for image formation, liquid crystal screen production, color filter production or offset printing. In particular,
It is useful for KrF and ArF excimer lasers.

[0046]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited by the examples unless it exceeds the gist thereof. Synthesis Example 1 (Synthesis of 1-ethoxyethylated polyhydroxystyrene) Polyhydroxystyrene (produced by Nippon Soda Co., Ltd., weight average molecular weight 15, 900, Mw / Mn 1.12) 30
g and 300 mL of 1,3-dioxolane were added and uniformly dissolved. Then, 15.0 g of ethyl vinyl ether was added, and the mixture was heated to 40 ° C. in a water bath. In addition, 36
0.3% hydrochloric acid was added and stirring was continued for 4 hours. After the reaction,
To this reaction solution, 3 mL of 28% aqueous ammonia was added and stirred for 30 minutes. This reaction solution was dropped into 3 L of pure water, and the resulting precipitate was filtered. Further, the precipitate was dissolved in acetone, and the solution was dropped into pure water to cause precipitation, whereby a target polymer was recovered. The precipitated polymer was dried under vacuum to obtain 37.1 g of 1-ethoxyethylated polyvinylphenol. The obtained polymer was dissolved in deuterated acetone, and the proton NMR spectrum was measured. As a result, a signal of an aromatic hydrogen having a δ value of 6.2 to 7.0 and an acetal methine hydrogen having a δ value of 5.2 to 5.5 were obtained. Area ratio with the signal was 10.2: 1. From this result, the acetalization rate was 39.4%. Synthesis Example 2 (Synthesis of dissolution inhibitor 1) The following structural formula (V) was placed in a 300 mL four-necked flask equipped with a nitrogen inlet tube, a stirrer, and a thermometer.

[0047]

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4.28 g of a compound represented by the formula (Bis-RS3P, manufactured by Honshu Chemical Co., Ltd.) and 1,3-dioxolane 2
0 mL and uniformly dissolved, and then 5.47 g of menthyl chloroformate was added.
Heated to 0 ° C. 2.53 g of triethylamine
5 mL of 1,3-dioxolane solution was added dropwise over 5 minutes,
After completion of the dropwise addition, stirring was continued for 3 hours. After the reaction, this reaction solution was dropped into 400 mL of pure water, and the resulting precipitate was filtered. Further, this precipitate was dissolved in acetone, and the solution was dropped into pure water to cause precipitation, thereby recovering a target substance having a menthyl carbonate group. The precipitated solid was dried under vacuum to obtain 4.89 g of dissolution inhibitor 1.

The obtained dissolution inhibitor 1 was dissolved in deuterated acetone, and the proton NMR spectrum was measured. The signal of aromatic hydrogen having a δ value of 7.0 to 7.4 and the δ value of 4.4 to 4 were measured. The area ratio to the methine hydrogen signal of 0.7 is
2.74: 1. From this result, the protection ratio of the phenolic hydroxyl group by the menthyl carbonate group was 94.9%.

Synthesis Example 3 (Synthesis of Dissolution Inhibitor 2) The compound represented by the above structural formula (V) (Bi) was placed in a 300 mL four-necked flask equipped with a nitrogen inlet tube, a stirrer, and a thermometer.
After adding 4.28 g of s-RS3P (manufactured by Honshu Chemical Co., Ltd.) and 30 mL of acetone and dissolving uniformly, N, N-
0.05 g of dimethylaminopyridine was added, and the mixture was heated to 40 ° C. in a water bath. To this, 11.0 g of di (tert-butyl) dicarbonate was added dropwise over 10 minutes, and stirring was continued for 4 hours after completion of the addition. After the reaction, this reaction solution was dropped into 1 L of pure water, and the resulting precipitate was filtered. Further, the precipitate was dissolved in acetone, and the solution was dropped into pure water to cause precipitation, thereby recovering the target substance. The precipitated solid was dried under vacuum to obtain 9.02 g of dissolution inhibitor 2.

The obtained dissolution inhibitor was dissolved in deuterated acetone, and the proton NMR spectrum was measured.
Signals of aromatic hydrogen having a δ value of 7.0 to 7.4 and a δ value of 1.
The area ratio to the signal of tert-butyl group hydrogen of 3 to 1.7 was 1.96: 6.74. From this result, t
The protection ratio of the phenolic hydroxyl group by the tert-butyl carbonate group was 99.3%.

Synthesis Example 4 (Synthesis of Photoacid Generator) (1) In a 1 L four-necked flask equipped with a nitrogen inlet tube, a stirrer, and a thermometer, 12.1 g of paraformaldehyde and 60 g of toluene were added, stirred, and concentrated. Hydrochloric acid (120 mL) was added, and the mixture was heated to 40 ° C. in a water bath. To this, 60 g of a toluene solution of 35.4 g of cyclohexanethiol was added dropwise over 20 minutes. After completion of the dropwise addition, the reaction solution was stirred while maintaining the temperature at 50 ° C. After confirming the completion of the reaction by TLC, the aqueous layer was discarded and made alkaline with a saturated aqueous sodium carbonate solution to obtain a toluene solution of chloromethylcyclohexyl sulfide.

(2) 4-methoxybenzenethiol7.
4 g was placed in a 200 mL flask, and 45.2 g of a 5 wt% sodium hydroxide solution in ethanol was added and stirred.
While cooling the flask with water, the toluene solution of chloromethylcyclohexyl sulfide obtained in (1) 27.
8 g were added dropwise over 5 minutes. After stirring for 2 hours, the temperature was raised to 70 ° C., and the mixture was further stirred for 1 hour. After adding 500 mg of sodium tungstate to this reaction solution, 25 g of 30% hydrogen peroxide solution was added over 1 hour, and the mixture was stirred for 5 hours. After extraction with toluene and drying over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure to obtain cyclohexylsulfonyl- (4-methoxyphenylsulfonyl) methane.

(3) 3.0 g of cyclohexylsulfonylhexylsulfonyl- (4-methoxyphenylsulfonyl) methane synthesized in (2) was placed in a flask, and 100 mL of ethanol was added and stirred. Further, 8.0 g of a 5 wt% solution of sodium hydroxide in ethanol was added to this solution and stirred. The reaction solution was cooled from -5 ° C to -10 ° C, and 35 mL of pure water was added. Then, 10 mL of an ethanol solution of 2.0 g of p-toluenesulfonyl azide was added dropwise over 5 minutes, and the mixture was stirred for 3 hours and allowed to stand. After standing overnight, the precipitate was collected by filtration to obtain a crude crystal. The crude crystals were recrystallized from ethanol to obtain cyclohexylsulfonyl- (4-methoxyphenylsulfonyl) diazomethane.

Example 1 0.60 g of the resin synthesized in Synthesis Example 1, 0.06 g of the dissolution inhibitor synthesized in Synthesis Example 2, 0.012 g of the photoacid generator synthesized in Synthesis Example 4, and salicylic acid as the organic carboxylic acid 0.0023 g, bis (2-hydroxyethyl) iminotris (hydroxymethyl) methane (structural formula (VI)) 0.0011 g as an additive,

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Embedded image

Florard FC430 as a surfactant
0.0004 g (manufactured by Sumitomo 3M) and propylene glycol monomethyl ether acetate 3.1 as a solvent
5 g and 0.65 g of ethyl lactate were mixed to prepare a resist photosensitive solution. In order to suppress the influence of the reflected light from the substrate on the resist pattern shape, an antireflection film DUV-42 (trade name, manufactured by Brewer Science) on a silicon substrate
Was prepared at a thickness of 800 nm, a resist photosensitive solution was spin-coated on the substrate, and baked on a hot plate at 90 ° C. for 60 seconds to form a resist film having a thickness of 0.72 μm. Further, in order to evaluate the resistance to the acidic protective film, polyvinylpyrrolidone and perfluorooctylsulfonic acid were dissolved in pure water on this resist film so as to have a solid concentration of 2.5 wt% and a pH of 2.0. Spin coating the aqueous solution to a thickness of 40 nm,
Baking was performed at 60 ° C. for 60 seconds. This resist film is subjected to a Nikon KrF excimer laser reduction projection exposure apparatus (NA =
0.42), and after exposure, 1
Baking was performed at 10 ° C. for 60 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. By observing the resist pattern obtained after this development with a scanning electron microscope, resolution, pattern shape, surface roughness of the resist film, depth of focus,
The edge roughness was evaluated.

The optimum exposure sensitivity is defined as the exposure amount at which a 0.30 μm line and space is resolved with a line width of 0.30 μm. The minimum resolution dimension of the line and space pattern at this time is defined as the resolution and Defined. Regarding the surface roughness of the resist film, 0.30 μm at the optimum exposure sensitivity was used.
The evaluation was made by observing the surface of the resist film of m lines and spaces with a scanning electron microscope. Also, the depth of focus is defined as the width of the exposure focal range where the resist cross-sectional shape of a 0.30 μm line-and-space resist at the optimal exposure sensitivity is observed with a scanning electron microscope and resolved without resist film loss. did. Regarding the edge roughness, a 0.30 μm line-and-space resist pattern at the optimum exposure sensitivity was similarly observed from above using a scanning electron microscope, and a five-step ranking was performed according to the presence or absence of unevenness of the resist pattern edge. Performed (5: none, 4: almost none, 3: present (poor), 2: considerably present (poor),
1: marked (bad). Table 1 shows the results.

Example 2 The same procedure as in Example 1 was repeated except that salicylic acid as an organic carboxylic acid component was not added.
The pattern shape, surface roughness of the resist film, depth of focus, and edge roughness were evaluated. Table 1 shows the results. Comparative Example 1 The resist resolving power, pattern shape, resist film surface roughness, depth of focus, and edge roughness were evaluated in exactly the same manner as in Example 1 except that the dissolution inhibitor 1 was changed to the dissolution inhibitor 2 of Synthesis Example 3. . Table 1 shows the results.

COMPARATIVE EXAMPLE 2 Except that the dissolution inhibitor 1 was changed to the dissolution inhibitor 2 synthesized in Synthesis Example 3, the resolution of the resist, the pattern shape, the surface roughness of the resist film, the depth of focus, The edge roughness was evaluated. Table 1 shows the results. Comparative Example 3 The resist resolving power, pattern shape, resist film surface roughness, depth of focus, and edge roughness were evaluated in exactly the same manner as in Example 2 except that the dissolution inhibitor 1 was not added. Table 1 shows the results.

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[Table 1]

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The radiation-sensitive resin composition of the present invention maintains good sensitivity and resolution by containing the above-mentioned specific compound in the chemically amplified positive-type radiation-sensitive resin composition, and furthermore, maintains the substrate. In addition, it is possible to form a good-shaped pattern having excellent environmental resistance, such as an upper protective film, having no film irregularity and edge roughness and having a large depth of focus.

Claims (9)

[Claims] (A) a phenolic hydroxyl group-containing alkali-soluble resin or a resin in which at least a part of the hydroxyl group is protected by an acid-decomposable protecting group, and (B) a group which is decomposed by the action of an acid to impart alkali solubility. In a positive-type radiation-sensitive resin composition containing a compound having a partial structure capable of producing a compound and (C) a compound capable of decomposing by actinic rays or radiation to generate an acid, the component (B) has alkali solubility. A positive radiation-sensitive resin composition comprising an alkyl carbonate group having 7 or more carbon atoms which may be substituted as a partial structure capable of forming a group to be imparted. 2. The positive radiation-sensitive resin composition according to claim 1, wherein the component (A) is a resin in which at least a part of a phenolic hydroxyl group is protected by an acid-decomposable protecting group. 3. The positive radiation-sensitive resin composition according to claim 1, wherein the acid-decomposable protecting group of the component (A) has a structure represented by the following general formula (I). Embedded image (However, R ¹ and R ² independently represent a hydrogen atom, an optionally substituted alkyl group or an optionally substituted alkoxy group, and R ³ represents an optionally substituted alkyl group. R ¹ and R ³ may combine to form a ring.) 4. Component (A) wherein at least a part of the phenolic hydroxyl group of the polyhydroxystyrene is represented by the general formula (I):
4. The positive-type radiation-sensitive resin composition according to claim 3, wherein the resin is a resin protected by the protective group shown in (1). 5. The positive radiation-sensitive resin composition according to claim 1, wherein the alkyl carbonate group of the component (B) is a group represented by the following general formula (II). object. Embedded image (Wherein, R ⁴ , R ⁵ and R ⁶ independently represent a hydrogen atom, an optionally substituted linear or branched alkyl group,
N may be 5 or more and 1
Represents a natural number of 5 or less. ) 6. The positive radiation-sensitive resin composition according to claim 1, wherein the alkyl carbonate group of the component (B) has a structure represented by the following general formula (III). . Embedded image (Wherein, R ^7, R ⁸ and R ⁹ .R ⁷ is representative of the optionally substituted independently a linear or branched alkyl radical, R
The total number of carbon atoms of ⁸ and R ⁹ is 5 or more. ) 7. The molecular weight of the component (B) is from 200 to 300.
The positive radiation-sensitive resin composition according to any one of claims 1 to 6, wherein the value is less than 0. 8. The positive type according to claim 1, wherein the component (B) is a compound in which at least a part of a phenolic hydroxyl group of a polynuclear phenol is substituted with the alkyl carbonate structure. Radiation-sensitive resin composition. 9. The method according to claim 1, further comprising an organic carboxylic acid.
8. The positive-type radiation-sensitive resin composition according to any one of 8.