JP2002196497A - Chemical amplification type positive type resist composition for thermal flow and pattern forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist composition and a pattern forming method thereto which can exhibit enough resolution in the ordinary pattern formation, reduce the pattern size by flow baking, and provide easy control of flow amount. SOLUTION: The chemical amplification type positive type resist composition for thermal flow comprises a specific hydroxyl-styrene resin (A) of which the 10 to 50 mol.% of hydroxyl groups are replaced with acid decomposable groups, the weight average molecular weight of 5,000 to 50,000, and the degree of dispersion of 1.0 to 1.3, a specific hydroxyl-styrene resin (B) of which the 10 to 50 mol.% of hydroxyl groups are replaced with acid decomposable groups and the weight average molecular weight of 5,000 to 50,000, and a photoacid generation agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist mask for manufacturing semiconductors, and more particularly to a resist for forming a contact hole and a method of forming a pattern thereof.

[0002]

2. Description of the Related Art A reduction projection exposure method using light (g-line, i-line, KrF excimer laser light) has been used.
In general, the resolution R of a lens is expressed by the following equation according to Rayleigh's theoretical equation. R = k [λ / (NA)] where λ is the exposure wavelength, and NA is the numerical aperture of the lens (Numeri
cal Aparature), when the angle of incidence on the wafer is θ, NA = sin θ. k indicates a different value depending on the resist, and is often used as a characteristic parameter indicating the performance of the resist. In the experience up to i-resist, even if the resist is improved, it can only be reduced to about 0.5. Increasing the resolving power, as is apparent from the above equation, means reducing R. To this end, it is necessary to increase NA or decrease λ, but reduce k. However, now NA also increases to a value approaching 0.7, and k reaches the limit of 0.5. From the viewpoint of further shortening the wavelength, KrF excimer laser light from 248 nm to ArF excimer laser light 19
Although 3 nm and 157 nm of F ₂ excimer laser light have been studied, development of resist materials and devices that can be used in actual semiconductor manufacturing has been delayed, so that resist materials that can form finer patterns with conventional exposure apparatuses have been developed. A pattern forming method has been desired.

[0003] The wafer is heated (flow bake) while irradiating ultraviolet rays (UV) in a vacuum disclosed in JP-A-6-37071 to change the resist shape (flow).
Although a method of adjusting the contact hole diameter of a semiconductor device that can reduce the size of a resist pattern is promising, development of a resist material suitable for the method has been insufficient. In addition, since the process of flow baking a wafer while irradiating UV in a vacuum is complicated, a resist material that can obtain the same effect only by flow baking in air has been desired. However, when a flow bake process is applied to a resist material known so far, problems such as a high flow rate and difficulty in controlling the hole size and a problem such as insufficient flow even at a practical flow temperature (150 ° C. or lower) are encountered. was there.

[0004]

SUMMARY OF THE INVENTION The present invention provides a resist material exhibiting a sufficient resolution even in a normal pattern forming method and suitable for reducing the pattern size only by flow baking, and a pattern forming method therefor. The purpose is to: ADVANTAGE OF THE INVENTION According to this invention, it shows sufficient resolving power also in normal pattern formation, and it is possible to make a pattern size small only by an appropriate flow bake temperature, and a flow speed is also appropriate and a flow amount is easy to control. A resist material is provided.

[0005]

Means for Solving the Problems The present inventors diligently studied constituent materials of a positive-type chemically amplified resist composition, and as a result, found that the use of the composition can achieve the object of the present invention. Invented the invention. That is, the above object is achieved by the following constitutions.

(1) 10 to 50 mol% of hydroxyl groups are substituted with an acid-decomposable group, the average weight molecular weight is 5,000 to 50,000 and the dispersity is 1.0
The following hydroxystyrene resin (A) having an average molecular weight of 5,000 to 50,000 in which 10 to 50 mol% of hydroxyl groups are substituted with an acid-decomposable group, and a photoacid generator. A chemically amplified positive resist composition for thermal flow, comprising:

[0007]

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In formulas (A) and (B), BL ₁ and B
L ₂ may be the same or different and represents an acid-decomposable group. L ₁ represents a hydrogen atom or a group not decomposed by an acid. 0.1
≦ a ≦ 0.5, 0.1 ≦ b ≦ 0.5, and 0.0 <c ≦ 0.3. (2) The chemically amplified positive resist composition for thermal flow as described in (1) above, wherein both the hydroxystyrene resins (A) and (B) have an average weight molecular weight of 5,000 to 30,000. (3) The above (1) or (2), wherein at least one of BL ₁ and BL ₂ in the formulas (A) and (B) is a group represented by the following formula (I) or (II). The chemically amplified positive resist composition for thermal flow according to the above item 2).

[0009]

Embedded image R ₁ represents an alkyl group having 1 to 4 carbon atoms. W is a straight chain,
Represents a branched or cyclic alkyl group having 1 to 10 carbon atoms. n represents an integer of 1 to 4. R ₄ represents a linear, branched or cyclic alkyl group having 4 to 10 carbon atoms. k is 0
Represents an integer of from 4 to 4. (4) The above (1) to (3) containing at least an onium salt represented by the following formula (III) and / or a sulfonyldiazomethane represented by the following formula (IV) as a photoacid generator:
5. The chemically amplified positive resist composition for thermal flow according to any one of the above.

[0010]

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In the formula (III), Ra _{1 to} Ra ₅ , Rb _{1 to} R
b _5, Rc ₁ ~Rc ₅ are each independently a hydrogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, a hydroxyl group, a halogen atom, or -S-R Represents a group. R represents a linear, branched or cyclic alkyl or aryl group. Also, Ra _{1 to} R
_{a 5, Rb 1 ~Rb 5,} Rc 1 ~Rc of _5, two or more are bonded, a single bond, carbon, oxygen, sulfur, and the ring containing one or more selected from nitrogen It may be formed.
X ^- is, R ₃ -SO ₃ ^- represents a ^- or R ₃ -COO. R
₃ is a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms or a substituted or unsubstituted aralkyl group having 6 to 20 carbon atoms, 1 to 20 linear, branched or cyclic perfluoroalkyl groups, or 6 to 20 carbon atoms
Represents a substituted or unsubstituted perfluoroaryl group. In the formula (IV), Rd ₁ and Rd ₂ each independently represent
It represents a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a substituted or unsubstituted aralkyl group having 6 to 20 carbon atoms.

(5) The chemically amplified positive resist composition for thermal flow according to any one of the above (1) to (4), further comprising a carboxylic acid and / or a carboxylic anhydride. (6) The chemically amplified positive resist composition for thermal flow according to any one of (1) to (5), further comprising a nitrogen-containing basic organic compound.

(7) On the semiconductor substrate, the above (1) to
After forming a photoresist film from the chemically amplified positive resist composition according to any of (6), pattern exposure, heat treatment, and development are sequentially performed with radiation having a wavelength of 300 nm or less, and the contact hole pattern is slightly larger than desired. And forming a contact hole pattern of a desired size by heating the semiconductor substrate to 120 ° C. to 160 ° C. and causing the resist to thermally flow.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, each component used in the present invention will be described in detail. [1] Resin In the above formulas (A) and (B), BL ₁ and BL ₂ are
It may be the same or different and represents an acid-decomposable group. Here, the acid-decomposable group is a group that is decomposed by an acid to make the resin alkali-soluble. BL ₁ and BL ₂ are not particularly limited as long as they are acid-decomposable groups, and are represented by the following general formula (I) or (I
The structure of I) is preferable, and the structure of the general formula (I) is particularly preferable.

[0015]

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In the formula, R ₁ represents an alkyl group having 1 to 4 carbon atoms. W is a linear, branched or cyclic C 1-10
Represents an alkyl group up to n represents an integer of 1 to 4. R
₄ represents a linear, branched or cyclic alkyl group having 4 to 10 carbon atoms. k represents an integer of 0 to 4.

BL ₁ is preferably a group represented by the general formula (I), and particularly, in the general formula (I), W is a straight-chain,
A branched or cyclic alkyl group having 1 to 6 carbon atoms, n is 1
Or a group that is 2. BL ₂ is preferably
In the general formula (I), W is a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms and n is 1 or 2, or R ₄ in the general formula (II)
Is a linear, branched or cyclic alkyl group having 4 to 6 carbon atoms, and k is 0 or 1.

L ₁ is not particularly limited as long as it is a group which is not decomposed by an acid. Preferably, L ₁ is a hydrogen atom, a linear or branched or cyclic alkyl group having 1 to 6 carbon atoms, a linear or branched alkyl group having 1 to 6 carbon atoms. Alternatively, it is a cyclic alkoxy group or a group selected from the group consisting of a halogen atom, a nitro group, an amino group and a cyano group. Particularly preferably, a hydrogen atom and a carbon number of 1 to 1.
6 linear, branched or cyclic alkyl groups, 1 to 1 carbon atoms
6 linear, branched or cyclic alkoxy groups.

The weight average molecular weight of each of the polymers (A) and (B) is 5,000 to 50,000, preferably 5,000 to 50,000.
30,000. The preferred range of the weight average molecular weight of the mixture of the polymers (A) and (B) is preferably 100
00 to 50000, particularly preferably 15000 to 300
00. If the molecular weight is smaller than the preferable range, the flow rate becomes extremely high, which is not preferable. On the other hand, when the molecular weight is larger than the preferable range, the heat resistance of the polymer becomes too high, and the resist flow does not occur in an appropriate temperature range, which is not preferable. Further, from the viewpoint of easy adjustment of the flow start temperature and the flow rate, the polymer (A)
It is preferable that the difference between the weight average molecular weight of the polymer and the polymer (B) is 1000 or more. The weight average molecular weight and the degree of dispersion can be obtained by gel permeation chromatography (in terms of polystyrene).

The polymer (A) / polymer (B) ratio is preferably used by mixing between 1/9 and 9/1 by weight. If the ratio of one polymer is 10% or less, the effect of the present invention is not sufficiently exhibited. More preferably, the polymer (A) /
Polymer (B) = 2/8 to 8/2, particularly preferably polymer (A) / polymer (B) = 3/7 to 7/3.

The polymer (A) / polymer (B) of the present invention
Are disclosed in European Patent 254853 and JP-A-2-25.
No. 850, No. 3-223860, No. 4-251259
As disclosed in US Pat. No. 6,086,098, an alkali-soluble resin is reacted with a precursor of an acid-decomposable group, or an alkali-soluble resin monomer having an acid-decomposable group bonded thereto is copolymerized with various monomers. Can be obtained. The polymer used in the present invention can be obtained by appropriately mixing the polymer thus obtained in accordance with the disclosure of the present invention. Alternatively, it can also be obtained by mixing the trunk polymers corresponding to the polymers (A) and (B) in advance, and reacting a precursor of an acid-decomposable group according to the same method as described above.

[2] Photoacid Generator The photoacid generator used in the present invention is a compound that generates an acid upon irradiation with actinic rays or radiation. Examples of such a photoacid generator include photoinitiators for photocationic polymerization, photoinitiators for photoradical polymerization, photodecolorants for dyes, photochromic agents, and known photoacids used in microresists and the like. (400 to 200 nm ultraviolet ray, far ultraviolet ray, particularly preferably g-line, h-line, i-line, KrF excimer laser beam), ArF excimer laser beam, electron beam, X-ray, molecular beam or ion beam to generate acid. Compounds and mixtures thereof can be appropriately selected and used.

More specifically, examples of the photoacid generator that can be used in the present invention include onium salts such as diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, arsonium salts, and the like. A halogen compound, an organic metal / organic halide, a photoacid generator having an o-nitrobenzyl-type protecting group, a compound which generates sulfonic acid by photodecomposition represented by iminosulfonate, a disulfone compound, a diazoketosulfone, Examples thereof include a diazodisulfone compound. Further, a group in which an acid is generated by such light or a compound in which a compound is introduced into a main chain or a side chain of a polymer can be used.

Further, VNRPillai, Synthesis, (1), 1 (198
0), A. Abad etal, Tetrahedron Lett., (47) 4555 (1971),
Compounds that generate an acid by light described in DHR Barton et al., J. Chem. Soc., (C), 329 (1970), U.S. Pat. No. 3,779,778, and EP 126,712 can also be used.

Preferred photoacid generators in the present invention include at least an onium salt represented by the following formula (III) and / or a sulfonyldiazomethane represented by the following formula (IV).

[0026]

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In the formula (III), Ra _{1 to} Ra ₅ , Rb ₁ to
Rb _5, Rc ₁ ~Rc ₅ are each independently a hydrogen atom, a linear,
Branched or cyclic alkyl group, linear, branched or cyclic alkoxy group, hydroxyl group, halogen atom,
Or a -SR group. R represents a linear, branched or cyclic alkyl or aryl group. Also, Ra _{1 to} R
_{a 5, Rb 1 ~Rb 5,} Rc 1 ~Rc of _5, two or more are bonded, a single bond, carbon, oxygen, sulfur, and the ring containing one or more selected from nitrogen It may be formed.
X ^- is, R ₃ -SO ₃ ^- represents a ^- or R ₃ -COO. R
₃ is a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms or a substituted or unsubstituted aralkyl group having 6 to 20 carbon atoms, 1 to 20 linear, branched or cyclic perfluoroalkyl groups, or 6 to 20 carbon atoms
Represents a substituted or unsubstituted perfluoroaryl group.

Ra _{1 to} Ra ₅ , Rb _{1 to} Rb ₅ , Rc _{1 to} Rc ₅ , R
Examples of the linear or branched alkyl group which may have a substituent include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, and a t-amyl group. Those having 1 to 6 carbon atoms are exemplified. Examples of the cyclic alkyl group include those having 3 to 8 carbon atoms which may have a substituent, such as a cyclopropyl group, a cyclopentyl group and a cyclohexyl group. Examples of the linear or branched alkoxy group include a methoxy group, an ethoxy group, a hydroxyethoxy group, a propoxy group, an n-butoxy group,
Those having 1 to 6 carbon atoms such as an isobutoxy group, a sec-butoxy group and a t-butoxy group are exemplified.

Examples of the cyclic alkoxy group include a cyclopentyloxy group and a cyclohexyloxy group. As the halogen atom, a fluorine atom, a chlorine atom,
Bromine atoms and iodine atoms can be mentioned. Examples of the aryl group for R include those having 6 to 14 carbon atoms which may have a substituent such as a phenyl group, a tolyl group, a methoxyphenyl group, and a naphthyl group. Preferably as these substituents, an alkoxy group having 1 to 4 carbon atoms,
Halogen atom (for example, fluorine atom, chlorine atom, iodine atom), aryl group having 6 to 10 carbon atoms, alkenyl group having 2 to 6 carbon atoms, cyano group, hydroxy group, carboxy group, Examples include an alkoxycarbonyl group and a nitro group.

Further, Ra _{1 to} Ra ₅ , Rb _{1 to} Rb ₅ , Rc _{1 to} Rc
₅ , one or two selected from a single bond, carbon, oxygen, sulfur, and nitrogen formed by combining two or more
Examples of the ring containing more than one kind include a furan ring, a dihydrofuran ring, a pyran ring, a trihydropyran ring, a thiophene ring, a pyrrole ring, and the like.

Ra _{1 to} Ra ₅ , Rb _{1 to} Rb ₅ , Rc _{1 to} Rc ₅ are
Preferably, a hydrogen atom, a straight chain having 1 to 6 carbon atoms, a branched or cyclic alkyl group, a straight chain having 1 to 6 carbon atoms,
Represents a branched or cyclic alkoxy group.

Preferred substituents which the aryl group and aralkyl group as R ₃ may have are those having 1 carbon atom.
To 5 alkyl groups, a fluoroalkyl group having 1 to 5 carbon atoms, and a halogen atom (particularly a fluorine atom). Preferred substituents that the alkyl group as R ₃ may have include alkoxy groups having 1 to 5 carbon atoms.

In the formula (IV), Rd ₁ and Rd ₂ each independently represent a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, Or a substituted or unsubstituted aralkyl group having 6 to 20 carbon atoms. Preferred substituents that the aryl group and aralkyl group represented by Rd ₁ and Rd ₂ may have include an alkyl group having 1 to 5 carbon atoms, a fluoroalkyl group having 1 to 5 carbon atoms, a halogen atom (particularly, a fluorine atom ) And a hydroxyl group. As the preferred substituents that the alkyl group have as Rd ₁ and Rd _2, and alkoxy group having 1 to 5 carbon atoms.

Specific examples of the photoacid generator include, but are not limited to, the following.

[0035]

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[0036]

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[3] Carboxylic Acid and Carboxylic Anhydride The composition of the present invention can be added with a carboxylic acid or carboxylic anhydride to increase the optimum flow temperature and reduce the flow rate.

[0038] Carboxylic anhydrides are more preferred. Specific examples of the carboxylic anhydride include maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, citraconic anhydride, α-methylglutaconic anhydride, tetrahydrophthalic anhydride, and hexahydroanhydride. Phthalic acid, chloromaleic anhydride, d-phenylmaleic anhydride, pyromellitic acid, hymic anhydride, 3,6-endomethylene-phthalic anhydride, terpene maleic anhydride adduct, α
-Terpinene-maleic anhydride adduct, 4,5-cyclohexene-dicarboxylic anhydride, 1-methyl-4,5-
Cyclohexene-dicarboxylic anhydride, 3,6-methylene 1,2,3,6-tetrahydro-cisphthalic anhydride, (4-carboxy-4-cyclohexenyl) acetic anhydride, 4-methyl-4,5-cyclohexene Dicarboxylic anhydride,

(4-carboxy-5-cyclohexenyl) acetic anhydride, 3,6-methylene-1,2,3,6-
Tetrahydro-cis-phthalic anhydride, 6
-(5-carboxy-bicyclo [2,2,1] -hepta-2-enyl) acetic anhydride, 3,6-methano-1-methyl 1,2,3,6-tetrahydrocisphthalic anhydride,
2-oxa-1,4-dioxo-5,8-methano-1,
2,3,4,4a, 5,8,8a-octahydronaphthalene, 5,8-methano 1,2,3,4,4a, 5,8,
8a-octahydronaphthalene-1,2-dicarboxylic anhydride, 5,8-methano-1-methyl-1,2,3,8
4,4a, 5,8,8a-octahydronaphthalene-
2,3-dicarboxylic anhydride, 1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene-2,3-dicarboxylic anhydride,

2-oxa-1,3-dioxo-1,2,2
3,4,4a, 5,8,8a, 9,9a, 10,10a
-Dodecahydroanthracene, 4- (5-bicyclo [2,2,1] -hepta-2-enyl) phthalic anhydride, phenolphthalein, 4- (2,5-dioxotetrahydrofuran-3-yl)- Tetralin-1,2-
Dicarboxylic anhydride, 5- (2,5-dioxotetrahydrofuranyl) -3-methyl-3-cyclohexene-
1,2-dicarboxylic anhydride, 4-methylcyclohexane-1,2-dicarboxylic anhydride, methylcyclohexene-1,2-dicarboxylic anhydride, endo-bicyclo [2,2,2] oct-5-ene -2,3-dicarboxylic anhydride and the like.

As the carboxylic acid, in addition to those corresponding to the above-mentioned carboxylic acid anhydrides, saturated or unsaturated aliphatic carboxylic acids, alicyclic carboxylic acids, oxycarboxylic acids, alkoxycarboxylic acids, ketocarboxylic acids, aromatic carboxylic acids Any of acid and the like can be used and is not particularly limited.

For example, monovalent or polyvalent aliphatic carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid and adipic acid, and 1,1-cyclohexanedicarboxylic acid Acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid,
Alicyclic carboxylic acids such as 1,1-cyclohexyldiacetate, acrylic acid, crotonic acid, isocrotonic acid, 3-butenoic acid, methacrylic acid, 4-pentenoic acid, propiolic acid, 2-butyric acid, maleic acid, fumaric acid Aliphatic carboxylic acids such as acetylene carboxylic acid, oxycarboxylic acids such as oxyacetic acid, alkoxycarboxylic acids such as methoxyacetic acid and ethoxyacetic acid, ketocarboxylic acids such as pyruvic acid and the general formulas (V) and (VI) And the like.

[0043]

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In the formula (V), R ¹³ and R ¹⁴ each independently represent a hydrogen atom, a hydroxyl group, a nitro group, a carboxyl group, or a vinyl group (however, when both R ¹³ and R ¹⁴ are hydrogen atoms, except). In the formula (VI), n is 0 or 1 to 10
Indicates an integer.

In particular, alicyclic carboxylic acids, unsaturated aliphatic carboxylic acids, and aromatic carboxylic acids are preferably used.

Examples of the aromatic carboxylic acid represented by the general formula (V) include p-hydroxybenzoic acid, o-hydroxybenzoic acid, 2-hydroxy-3-nitrobenzoic acid, and 3,5-dinitrobenzoic acid , 2-nitrobenzoic acid,
2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid,
2-vinylbenzoic acid, 4-vinylbenzoic acid, phthalic acid,
Terephthalic acid, isophthalic acid, and the like,
Particularly, benzoic acid having a substituent at the o-position, for example, o-hydroxybenzoic acid, o-nitrobenzoic acid, phthalic acid and the like are preferable.

Further, as the aromatic carboxylic acid compound represented by the general formula (VI), only one in which n is a single one,
Alternatively, a combination of different types can be used, but practically, SAX (trade name, manufactured by Mitsui Toatsu Chemicals, Inc.) commercially available as a phenol compound is preferably used.

Each of the carboxylic acids and carboxylic anhydrides can be used alone or in combination of two or more. A preferable addition amount is 5% by weight or less, preferably 0.1 to 3% by weight based on the solid content of the composition excluding the solvent.
% By weight.

[4] Organic Basic Compound The preferred organic basic compound (C) which can be used in the present invention is a compound having a higher basicity than phenol. Among them, a nitrogen-containing basic compound is preferable. (C) Addition of an organic basic compound improves sensitivity variation with time. Examples of such an organic basic compound include those having a structure shown below.

[0050]

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Where R²⁵⁰, R²⁵¹And R²⁵²Are each
Independently, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms,
1-6 aminoalkyl groups, hydroxy having 1-6 carbon atoms
Alkyl group or substituted or unsubstituted 6 to 20 carbon atoms
An aryl group, where R ²⁵¹And R²⁵²Are connected to each other
To form a ring.

[0052]

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Wherein R ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R
²⁵⁶ independently represent an alkyl group having 1 to 6 carbon atoms.) Further preferred compounds are nitrogen-containing basic compounds having two or more nitrogen atoms having different chemical environments in one molecule,
Particularly preferred are compounds containing both a substituted or unsubstituted amino group and a ring structure containing a nitrogen atom, or compounds having an alkylamino group. Preferred specific examples include substituted or unsubstituted guanidine, substituted or unsubstituted aminopyridine, substituted or unsubstituted aminoalkylpyridine, substituted or unsubstituted aminopyrrolidine, substituted or unsubstituted indazol, substituted or unsubstituted Pyrazole, substituted or unsubstituted pyrazine,
Substituted or unsubstituted pyrimidine, substituted or unsubstituted purine, substituted or unsubstituted imidazoline, substituted or unsubstituted pyrazoline, substituted or unsubstituted piperazine, substituted or unsubstituted aminomorpholine, substituted or unsubstituted amino And alkyl morpholine. Preferred substituents are an amino group, an aminoalkyl group, an alkylamino group, an aminoaryl group, an arylamino group, an alkyl group, an alkoxy group, an acyl group, an acyloxy group, an aryl group, an aryloxy group, a nitro group,
A hydroxyl group and a cyano group.

Preferred specific examples of the nitrogen-containing basic compound include guanidine, 1,1-dimethylguanidine,
1,3,3, -tetramethylguanidine, 2-aminopyridine, 3-aminopyridine, 4-aminopyridine,
-Dimethylaminopyridine, 4-dimethylaminopyridine, 2-diethylaminopyridine, 2- (aminomethyl) pyridine, 2-amino-3-methylpyridine, 2-
Amino-4-methylpyridine, 2-amino-5-methylpyridine, 2-amino-6-methylpyridine, 3-aminoethylpyridine, 4-aminoethylpyridine, 3-aminopyrrolidine, piperazine, N- (2-amino Ethyl) piperazine, N- (2-aminoethyl) piperidine, 4-amino-2,2,6,6-tetramethylpiperidine, 4-piperidinopiperidine, 2-iminopiperidine, 1- (2-aminoethyl) Pyrrolidine, pyrazole, 3-amino-5-methylpyrazole, 5-amino-
3-methyl-1-p-tolylpyrazole, pyrazine, 2
-(Aminomethyl) -5-methylpyrazine, pyrimidine, 2,4-diaminopyrimidine, 4,6-dihydroxypyrimidine, 2-pyrazoline, 3-pyrazoline, N-
Aminomorpholine, N- (2-aminoethyl) morpholine, 1,5-diazabicyclo [4.3.0] nona-
5-ene, 1,8-diazabicyclo [5.4.0] undec-7-ene, 1,4-diazabicyclo [2.2.2]
Octane, 2,4,5-triphenylimidazole, N
-Methylmorpholine, N-ethylmorpholine, N-hydroxyethylmorpholine, N-benzylmorpholine, cyclohexylmorpholinoethylthiourea (CHMET
U) and other tertiary morpholine derivatives, JP-A-11-5257
No. 5 hindered amines (for example, those described in the gazette [0005]) and the like, but are not limited thereto.

Particularly preferred specific examples are 1,5-diazabicyclo [4.3.0] non-5-ene, 1,8-diazabicyclo [5.4.0] undec-7-ene, 1,4-diazabicyclo [2.2.2] Tertiary morpholines such as octane, 4-dimethylaminopyridine, hexamethylenetetramine, 4,4-dimethylimidazoline, pyrroles, pyrazoles, imidazoles, pyridazines, pyrimidines, CHMETU, etc., and bis Hindered amines such as (1,2,2,6,6-pentamethyl-4-piperidyl) sebagate, N, N-dicyclohexylmethylamine and the like can be mentioned. Among them, 1,5-diazabicyclo [4.3.0] non-5-ene, 1,8-diazabicyclo [5.4.0] undec-7-ene, 1,4-diazabicyclo [2.2.2] Octane, 4-dimethylaminopyridine, hexamethylenetetramine, CHMETU,
Bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebagate and N, N-dicyclohexylmethylamine are preferred.

These organic basic compounds are used alone or in combination of two or more. The amount of the organic basic compound to be used is generally 0.001 to 10% by weight, preferably 0.1 to 10% by weight, based on the solid content of the entire photosensitive resin composition.
01 to 5% by weight. If the amount is less than 0.001% by weight, the effect of the addition of the organic basic compound cannot be obtained. Meanwhile, 1
If it exceeds 0% by weight, the sensitivity tends to decrease and the developability of the unexposed area tends to deteriorate.

[5] Acid-Decomposable Dissolution Inhibitors Acid-decomposable dissolution-inhibiting compounds that can be preferably used in the composition of the present invention include, for example, low-molecular acid-decomposable compounds described in Japanese Patent Nos. 2919142 and 2655384. Dissolution inhibitor compounds can be used. The addition of the acid-decomposable dissolution inhibitor enhances the dissolution contrast and improves the resolving power and defocus latitude (DOF). In addition, since it acts as a plasticizer, the optimum flow temperature can be lowered or the flow rate can be increased, so that it is also effective as a regulator of flow characteristics. The preferred amount of the acid-decomposable dissolution inhibitor is 10% in the composition.
% By weight, preferably 5% by weight or less.

[6] Fluorine and / or Silicon Surfactant The positive photoresist composition of the present invention preferably contains a fluorine and / or silicon surfactant.
The positive photoresist composition of the present invention may contain a fluorine-based surfactant, a silicon-based surfactant, or a surfactant containing both a fluorine atom and a silicon atom, or may contain two or more kinds. preferable. When the positive photoresist composition of the present invention contains the above-mentioned acid-decomposable resin and the above-mentioned surfactant, the density dependency is improved.

As these surfactants, for example, those described in
No. 62-36663, JP-A-61-226746, JP-A-61-226745,
JP-A-62-170950, JP-A-63-34540, JP-A-7-23016
No. 5, JP-A-8-62834, JP-A-9-54432, JP-A-9-598
No. 8, U.S. Pat.No. 5,405,720, No. 5360692, No. 5529881,
No. 5296330, No. 5436098, No. 5576143, No. 5294511
And No. 5824451. The following commercially available surfactants can also be used as they are. As commercially available surfactants that can be used, for example, F-top EF301, EF303, (manufactured by Shin-Akita Kasei Co., Ltd.), Florad FC
430, 431 (Sumitomo 3M Limited), Mega Fuck F171,
F173, F176, F189, R08 (Dai Nippon Ink Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troysol S-366 (Troy Chemical Co., Ltd.) )) Or a silicon-based surfactant. Also, polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can be used as a silicon-based surfactant.

The amount of the surfactant is usually 0.001 to 2% by weight, preferably 0.01 to 1% by weight, based on the solid content in the composition of the present invention. These surfactants may be added alone or in some combination. Examples of the surfactant that can be used in addition to the above include, specifically, polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether. , Polyoxyethylene alkyl allyl ethers such as polyoxyethylene octyl phenol ether, polyoxyethylene nonyl phenol ether, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan Sorbitan fatty acid esters such as monooleate, sorbitan trioleate, sorbitan tristearate, polyoxyethylene sorbitan Nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as laurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate And the like. The amount of these other surfactants is usually 2 parts by weight or less, preferably 1 part by weight or less, per 100 parts by weight of the solids in the composition of the present invention.

[7] Solvent The positive photoresist composition of the present invention comprises, as a coating solvent, propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate, and methyl lactate and ethyl lactate. Alkyl lactates, propylene glycol monomethyl ether,
Propylene glycol monoalkyl ethers such as propylene glycol monoethyl ether; ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether; ethylene glycol monoethyl ether; ethylene glycol monoalkyl ether such as ethylene glycol monomethyl ether acetate and ethylene glycol monoethyl ether acetate Alkyl ether acetates, 2-heptanone, γ-butyrolactone, methyl methoxypropionate, alkyl alkoxylates such as ethyl ethoxypropionate, methyl pyruvate, alkyl pyruvates such as ethyl pyruvate, N-methylpyrrolidone, Using at least one solvent selected from N, N-dimethylacetamide, dimethylsulfoxide, etc. It is applied.

Preferred are propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, methyl lactate and ethyl lactate. These solvents may be used alone or as a mixture. However, since the number of development defects is reduced, one or more solvents are selected and mixed from propylene glycol monoalkyl ether acetates and alkyl lactates. Is particularly preferred. Here, these mixing ratios are preferably 95/5 to 30/70 by weight. In the present invention, the solid content of the resist composition containing each of the above components is added to the above mixed solvent in a concentration of 3 to 25% by weight as a solid content concentration.
It is preferably dissolved, more preferably 5 to 22% by weight, and still more preferably 7 to 20% by weight.

[8] Other Additives The positive photoresist composition of the present invention may further contain, if necessary, a dye, a plasticizer, a photosensitizer, and a compound which promotes solubility in a developing solution. It can be contained.

Such a positive photoresist composition of the present invention is applied on a substrate to form a thin film. The thickness of this coating film is preferably from 0.2 to 1.2 μm. In the present invention, if necessary, a commercially available inorganic or organic antireflection film can be used.

Examples of the antireflection film include inorganic film types such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, α-silicon, SiON, tungsten Si, and polysilicon, and organic film types composed of a light absorbing agent and a polymer material. Can be used. The former is a vacuum evaporation system for film formation, CV
Equipment such as D equipment and sputtering equipment is required. Examples of the organic antireflection film include those comprising a condensate of a diphenylamine derivative and a formaldehyde-modified melamine resin described in JP-B-7-69611, an alkali-soluble resin, and a light absorbing agent, and a maleic anhydride copolymer described in US Pat. No. 5,294,680. A reaction product of the union and a diamine type light absorbing agent, one containing a resin binder and a methylolmelamine-based thermal crosslinking agent described in JP-A-6-118631, JP-A-6-11
No. 8656, an acrylic resin type anti-reflection film having a carboxylic acid group, an epoxy group and a light absorbing group in the same molecule, a film comprising a methylolmelamine and a benzophenone light absorbing agent described in JP-A-8-87115, and a method disclosed in JP-A-8-179509.
And a low-molecular-weight light absorbing agent added to the polyvinyl alcohol resin described in the above publication. As an organic antireflection film, Brewer Science DUV30 series, DUV-40 series, Shipley AC-2,
AC-3 or the like can also be used.

The resist solution is applied onto a substrate (eg, a silicon / silicon dioxide coating) used for manufacturing precision integrated circuit devices (on a substrate provided with the antireflection film as required), a spinner, a coater, and the like. After coating by an appropriate coating method such as that described above, exposure through a predetermined mask, baking and development can provide a good resist pattern. Here, the exposure light is preferably 150
It is light having a wavelength of nm to 250 nm. Specifically, Kr
F excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (157
nm), X-rays, electron beams and the like. Examples of the developer include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia; primary amines such as ethylamine and n-propylamine; diethylamine;
Secondary amines such as -butylamine, triethylamine,
Tertiary amines such as methyldiethylamine, alcoholamines such as dimethylethanolamine and triethanolamine, quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide, and cyclic amines such as pyrrole and pichelidine. An alkaline aqueous solution can be used. Further, an appropriate amount of an alcohol or a surfactant may be added to the above alkaline aqueous solution.

After forming a photoresist film on a semiconductor substrate using the chemically amplified positive resist composition of the present invention,
Pattern exposure, heat treatment, and development processing are sequentially performed with radiation having a wavelength of 300 nm or less, and the diameter after development is about 1
A contact hole having a desired size can be obtained by forming a contact hole larger than 0 nm to 150 nm and heating the substrate at 120 ° C. to 160 ° C. for 30 seconds to 120 seconds to cause the resist to thermally flow. For example, a diameter of 150 nm can be obtained by a heat flow from a diameter of 150 nm.

[0068]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples.

[Examples 1 to 9 and Comparative Examples 1 and 2] Table 1
Are dissolved in 700 parts by weight of PGMEA (propylene glycol monoethyl ether acetate),
The solution was filtered through a 0.1 μm filter to prepare a resist solution.

Comparative Example 3 According to Example 1 of Japanese Patent No. 2998682, 100 parts by weight of a t-BOC-protected polyhydroxystyrene resin having a weight-average molecular weight of 20,000 and 20 parts by weight of a t-BOC-protected polyhydroxystyrene resin having a weight-average molecular weight of 2,000 Parts, 5 parts by weight of triphenylsulfonium hexafluoroantimonene as a photoacid generator, PEGMEA
A solution containing 80 parts by weight of was prepared and filtered through a 0.1 μm filter to prepare a resist solution.

Comparative Example 4 According to Example 1 of Japanese Patent No. 2960656, polyhydroxystyrene obtained by substituting 35% of hydroxyl groups with tert-butoxycarbonyloxy group was used.
48 g and 1.48 g of polyhydroxystyrene in which 35% of hydroxyl groups were substituted with ethoxyethoxy groups were added to PEGMEA16.
The solution was dissolved in 8 g, and 0.148 g of bis (cyclohexylsulfonyl) diazomethane and 0.093 g of benzophenone were further added. The solution was adjusted and filtered with a 0.1 μm filter to prepare a resist solution. [Comparative Example 5] According to Example 2 of Japanese Patent No. 2960656, benzophenone was not added in Comparative Example 3 described above,
A resist solution was prepared.

Each of the resist solutions obtained above was applied to a DUV-44 (Brewer) on a silicon wafer using a spin coater.
Science Co.) applied on a substrate with a thickness of 60 nm,
Baking was performed for 90 seconds to obtain a resist film having a thickness of 0.76 μm.

[0073]

[Table 1]

The acid-decomposable dissolution inhibitor, nitrogen-containing basic compound, carboxylic acid compound and resin used are shown below. The photoacid generator is as described above.

[0075]

Embedded image

[0076]

Embedded image

[0077]

Embedded image

[0078]

Embedded image

[0079]

Embedded image

In the above, Mw is the weight average molecular weight, P
d represents the degree of dispersion.

The resist film was subjected to pattern exposure using a 248 nm KrF excimer laser stepper (NA = 0.55) through a 6% halftone mask. After exposure, heating is performed at 110 ° C. for 90 seconds, and immediately, 0.26N tetramethylammonium hydroxide (TMAH)
Development was carried out with an aqueous solution for 60 seconds, followed by rinsing with water for 30 seconds and drying. The wafer thus obtained was processed on a hot plate for 90 seconds (flow bake processing).
Hereinafter, the temperature of the hot plate during the flow bake processing is referred to as a flow bake temperature.

The pattern on the wafer not subjected to the flow bake treatment was observed with a scanning electron microscope, and the exposure amount at which the mask size portion of 250 nm (mask size) became 200 nm (first target size) was determined as the optimum exposure amount.
At the optimal exposure dose, how the dimensions of the first target size change due to the difference in the flow bake temperature was measured. From the graph of FIG.
flow rate at which the hole size becomes m) and the flow rate were evaluated. Furthermore, by observing the shape of the cross section at the time the first target size has flow 130nm with a scanning electron microscope, and measuring the length of △ L _L and △ L _R shown in FIG. 2, (△
L _L + ΔL _R ) / 2 was calculated as the bite amount, and the hole shape after the flow was evaluated. The smaller the bite, the better. Table 2 shows the evaluation results.

[0083]

[Table 2]

[0084]

According to the present invention, it is possible to exhibit a sufficient resolving power even in ordinary pattern formation, to reduce the pattern size only at an appropriate flow baking temperature, to set a suitable flow rate, and to reduce a flow amount. A resist material that can be easily controlled can be provided.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a contact hole size (nm) and a flow bake temperature (° C.) for calculating a flow rate and an optimum flow temperature.

FIG. 2 is a schematic diagram showing measurement points ΔL _L and ΔL _R in a resist for calculating a bite amount as an evaluation of a hole shape after a flow.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C08K 5/41 C08K 5/41 C08L 25/18 C08L 25/18 H01L 21/027 H01L 21/30 502R 570F Term (reference) 2H025 AA02 AA03 AB16 AC04 AC08 AD03 BE00 BE07 BE10 CB17 CB41 CB45 CB55 CB56 CC20 FA17 4J002 BC121 EF017 EF027 EF037 EF047 EF067 EF077 EF087 EF107 EF117 EF127 EU28 EU137 EU0 EU028 EU137 EU0 EU28 EU137 EU147 EU098 GP03 GQ05 5F046 AA25 BA04 CA08 LA18

Claims (7)

[Claims] An average weight molecular weight in which 10 to 50 mol% of hydroxyl groups are substituted with an acid-decomposable group, and a dispersity of 1.0 to 1.50.
The following hydroxystyrene resin (A), which is 3, and one of the hydroxyl groups
When the average weight molecular weight obtained by substituting 0 to 50 mol% with an acid-decomposable group is 5,
The following hydroxystyrene resin (B) having a molecular weight of 000 to 50,000
And a chemically amplified positive resist composition for thermal flow, comprising a photoacid generator. Embedded image In the formulas (A) and (B), BL ₁ and BL ₂ may be the same or different and represent an acid-decomposable group. L ₁ represents a hydrogen atom or a group not decomposed by an acid. 0.1 ≦ a ≦ 0.5,
0.1 ≦ b ≦ 0.5 and 0.0 <c ≦ 0.3. 2. Hydroxystyrene resins (A) and (B)
2. The chemically amplified positive resist composition for thermal flow according to claim 1, wherein the average weight molecular weights of both are 5,000 to 30,000. 3. 3. BL ₁ and B in formulas (A) and (B)
L _{2 has} at least one of the following formula (I) or formula (II)
The chemically amplified positive resist composition for thermal flow according to claim 1 or 2, wherein the group is represented by the following formula: Embedded image R ₁ represents an alkyl group having 1 to 4 carbon atoms. W is a straight chain,
Represents a branched or cyclic alkyl group having 1 to 10 carbon atoms. n represents an integer of 1 to 4. R ₄ represents a linear, branched or cyclic alkyl group having 4 to 10 carbon atoms. k is 0
Represents an integer of 1 to 4. 4. The photoacid generator according to claim 1, wherein at least one of the following formula (II)
Onium salt represented by I) and / or the following formula (IV)
A sulfonyldiazomethane represented by the formula:
4. The chemically amplified positive resist composition for thermal flow according to 3. Embedded image In the formula (III), Ra _{1 to} Ra ₅ , Rb _{1 to} Rb ₅ , Rc _{1 to} R
c ₅ independently represents a hydrogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, a hydroxyl group, a halogen atom, or an -S-R groups. R represents a linear, branched or cyclic alkyl or aryl group. Further, Ra _{1 to} Ra ₅ , Rb _{1 to} R
Of _{b 5, Rc 1 ~Rc 5,} 2 or more are bonded, a single bond,
It may form a ring containing one or more selected from carbon, oxygen, sulfur and nitrogen. X ^- is R _3-
SO ₃ ^- or R ₃ -COO ^- represents a. R ₃ has 1 to 1 carbon atoms
Up to 20 straight-chain, branched or cyclic alkyl groups, substituted or unsubstituted aryl groups having 6 to 20 carbon atoms or substituted or unsubstituted aralkyl groups having 6 to 20 carbon atoms, linear chains having 1 to 20 carbon atoms Represents a branched or cyclic perfluoroalkyl group, or a substituted or unsubstituted perfluoroaryl group having 6 to 20 carbon atoms. In the formula (IV), Rd ₁ and Rd ₂ each independently represent a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or 6-20
Represents a substituted or unsubstituted aralkyl group. 5. The chemically amplified positive resist composition for thermal flow according to claim 1, further comprising a carboxylic acid and / or a carboxylic anhydride. 6. The chemically amplified positive resist composition for thermal flow according to claim 1, further comprising a nitrogen-containing basic organic compound. 7. After forming a photoresist film on a semiconductor substrate using the chemically amplified positive resist composition according to any one of claims 1 to 6, pattern exposure with radiation having a wavelength of 300 nm or less, heat treatment, A pattern forming method of forming a contact hole pattern of a desired size by sequentially performing a development process to form a contact hole pattern slightly larger than desired, heating the semiconductor substrate to 120 ° C. to 160 ° C., and causing the resist to flow through the resist.