JPH0777799A - Resist composition - Google Patents

Abstract

PURPOSE:To provide the resist material superior in resist characteristics, such as sensitivity, resolution, etching resistance, and storage stability. CONSTITUTION:This resist composition is characterized by containing a 1,2- naphthoquinonediazido compound and a copolymer having in a molecular chain, structural units represented by formula I and II in which each of R<1> and R<2> is, independently, H, optionally substituted 1-5C alkyl, halogen, or cyano; R<3> is a linear or cyclic acetal group, carbonate, or -OR<4>; R<5> is H, optionally substituted 1-5C alkyl, halogen, or cyano: and R<6> is optionally substituted 5-16 cyclic alkyl.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist composition, and more particularly to a resist material capable of forming a pattern by irradiation with ultraviolet rays, KrF excimer laser light or the like. The resist composition of the present invention is particularly suitable as a positive resist for fine processing of semiconductor devices.

[0002]

2. Description of the Related Art In order to form a fine pattern using a resist, in general, a solution containing the resist is applied on a substrate and dried to form a photosensitive film, which is then irradiated with actinic rays to form a latent image. Form. It is then developed to form a negative or positive image. The resist is roughly classified into a positive type and a negative type.In the positive type, the exposed portion has a higher solubility in a developing solution than the unexposed portion to give a positive type image, and in the negative type, it is oppositely applied. The solubility of the exposed areas is reduced to give a negative tone image. When a semiconductor is manufactured by fine processing using a resist, a silicon wafer is used as a substrate, and an image (pattern) is formed on the surface of the silicon wafer by the above-mentioned lithography technique.
Then, etching is performed using the resist remaining on the substrate as a protective film, and then the remaining resist is removed.

In recent years, with the increasing integration, densification and miniaturization of semiconductor elements in ICs, LSIs and VLSIs,
There is a demand for a technique for forming a fine pattern of μm or less. However, it is extremely difficult to form a fine pattern of 1 μm or less with high precision by the conventional photolithography technique using near-ultraviolet rays or visible light, and the yield is significantly reduced. Therefore, light (wavelength 350
In order to improve the resolution by replacing the conventional photolithography using ~ 450 nm ultraviolet light), far-short ultraviolet light, KrF excimer laser light (wavelength 248 nm)
The lithography technology using a krypton fluoride laser that emits light of the above) is being studied.

The resist material, which is the center of this lithography technique, is required to have many high-level characteristics.
Among these, sensitivity, resolution, etching resistance, and storage stability are important. However, conventionally developed resist materials do not fully satisfy all of these performances, and improvement in performance is strongly desired.

For example, a negative resist such as polyglycidyl methacrylate has high sensitivity, but is inferior in resolution and dry etching resistance. Positive resists such as polymethylmethacrylate have good resolution but poor sensitivity and dry etching resistance. Also, wavelengths 350 to 4
When a novolac-based positive photoresist that has been used for UV exposure at 50 nm is exposed to deep UV, the resist itself absorbs too much light to the light source, so that a good fine pattern cannot be formed.

In recent years, attention has been focused on increasing the sensitivity of resists utilizing an acid catalyst and a chemical amplification effect. For example, (1) a base polymer, (2) a photoacid generator (an acid is generated by irradiation with actinic rays). A fine processing resist consisting of a three-component system of a compound) and (3) an acid-sensitive substance (a substance that reacts with an acid generated by light as a catalyst to change the solubility of a base polymer) has been developed. . This is one in which an acid-sensitive substance reacts with an acid generated by light as a catalyst to change the solubility of the base polymer to form a positive or negative resist.
For example, a positive resist comprising a novolac resin, a photo-acid generator and a dissolution inhibitor is known (Japanese Patent Laid-Open No. 3-10).
7160). The dissolution inhibitor has a dissolution inhibiting effect on the novolak resin, and reacts with an acid to exhibit a dissolution promoting action.

Further, the functional group which governs the solubility of the base polymer is blocked to make it insoluble, and the acid generated by light is used as a catalyst to remove the block to dissolve the polymer base in the developing solution. A positive type resist that restores the property is also known. However, the conventional resists are still insufficient in view of recent high performance standards.

By the way, recently, an acid-labile polymer having a recurring branched group consisting of a carboxylic acid t-butyl ester or a phenol t-butyl carbonate and being exposed to radiation. There has been proposed a resist composition containing a photopolymerization initiator which generates an acid when exposed (Japanese Patent Publication No. 27660/1990). When the coating film formed from this resist composition is irradiated with ultraviolet rays, electron beams or X-rays, acid-labile repeatedly present branched groups of the polymer in the irradiated portion are cleaved (cl).
eave) to form polar, recurring groups. This causes a large change in the solubility characteristics of the exposed and unexposed areas of the polymer coating. Then, the exposed areas are selectively removed by being treated with an alkaline developer or a polar solvent, while the unexposed areas are non-polar and thus selectively removed by being treated with a non-polar solvent. It Therefore, the resist composition acts as a positive type or a negative type by selecting a developing solution. In this publication, the polymer is poly (t
-Butoxycarbonyloxystyrene) has been specifically proposed, but KrF excimer laser light (248n
The transmittance in m) is insufficient and the pattern shape is deteriorated. Therefore, it has been strongly desired to develop a new resist satisfying the above-mentioned performance.

[0009]

The object of the present invention is to have excellent resist characteristics such as sensitivity, resolution, etching resistance, and storage stability, and to improve the resist pattern shape because the transmittance is improved by exposure. Another object is to provide a resist material. Another object of the present invention is to provide a resist material suitable for lithography using deep ultraviolet rays having a short wavelength or KrF excimer laser light. Another object of the present invention is to provide a resist composition particularly suitable as a positive resist for fine processing of semiconductor devices.

The inventors of the present invention have conducted extensive studies in order to overcome the above-mentioned problems of the prior art, and as a result, have found that a copolymer having a specific structural unit having an acid labile group and a photoacid generator. It was found that the above object can be achieved by combining a 1,2-naphthoquinonediazide compound as an agent, and the present invention has been completed based on the finding.

[0011]

Thus, according to the present invention, the following general formula (I) and general formula (II) are contained in the molecular chain.
A copolymer (A) having a structural unit represented by
Provided is a resist composition containing a 2-naphthoquinonediazide compound (B).

[0012]

[Chemical 5] In the formula, R ¹ and R ² are the same or different from each other and are a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a substituted alkyl group having 1 to 5 carbon atoms, a halogen atom or a cyano group, and R ³
Is linear acetal group, cyclic acetal group, a carbonate group, or -OR ^4. However, R ⁴ is

[0013]

[Chemical 6] Or

[0014]

[Chemical 7] Is.

However, in these formulas, R ⁷ , R ⁸ , R ⁹ ,
R ¹⁰ , R ¹¹ and R ¹² are each independently a chain alkyl group, a substituted chain alkyl group, a branched alkyl group, a substituted branched alkyl group, a cyclic alkyl group, a substituted cyclic alkyl group,
It represents an alkenyl group, a substituted alkenyl group, an aryl group, a substituted aryl group, an aralkyl group, or a substituted aralkyl group, and of these, R ¹⁰ and R ¹¹ may be a hydrogen atom.

[0016]

[Chemical 8] In the formula, R ⁵ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms,
It is a substituted alkyl group having 1 to 5 carbon atoms, a halogen atom, or a cyano group, and R ⁶ is a cyclic alkyl group having 5 to 16 carbon atoms or a substituted cyclic alkyl group having 5 to 16 carbon atoms. Further, according to the present invention, there is provided a resist composition in which the resist composition further contains an alkali-soluble phenol resin.

The present invention will be described in detail below. (Copolymer) The copolymer used in the present invention is a copolymer having a structural unit represented by the general formula (I) and a structural unit represented by the general formula (II) in the molecular chain, It is not particularly limited. In these general formulas,
As the substituted alkyl group having 1 to 5 carbon atoms, examples of the substituent include an alkyl group having a halogen atom. Further, the linear acetal group is a linear acetal group having 2 to 16 carbon atoms, the cyclic acetal group is a cyclic acetal group having 3 to 17 carbon atoms, and the carbonate group is a carbonate group having 2 to 15 carbon atoms. Can be mentioned.

Further, in R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ , (1) the chain alkyl group is a chain alkyl group having 1 to 5 carbon atoms, (2) a substituted chain As the alkyl group having 1 to 5 carbon atoms,
Examples of the substituent include a substituted chain alkyl group having a halogen atom, (3) a branched alkyl group having a carbon number of 3 to 8, and (4) a substituted branched alkyl group having a carbon number. 3-8
Then, as the substituent, for example, a substituted branched alkyl group having a halogen atom, and (5) the cyclic alkyl group has a cyclic alkyl group having 5 to 16 carbon atoms (provided that the cyclic alkyl-alkyl group is included). 6) The substituted cyclic alkyl group has 5 to 16 carbon atoms.
Then, as a substituent, for example, a substituted cyclic alkyl group having a halogen atom, (7) an alkenyl group has a carbon number of 2 to 7, and (8) a substituted alkenyl group has a carbon number of 2 to 7, Examples of the substituent include a substituted alkenyl group having a halogen atom, (9) an aryl group having 6 to 16 carbon atoms, and (10) a substituted aryl group having 6 to 16 carbon atoms.
As the substituent, for example, a substituted aryl group having a halogen atom or a nitro group, (11) the aralkyl group has 7 to 16 carbon atoms, and (12) the substituted aralkyl group has 7 to 16 carbon atoms.
It is preferable that the substituent is, for example, a substituted aralkyl group having a halogen atom or a nitro group.

As the method for obtaining the copolymer used in the present invention, the monomers which give the structural units of the general formula (I) and the general formula (II) are copolymerized, or a high molecular reaction is generally carried out. Examples thereof include a method of producing a copolymer having the structural units of formula (I) and general formula (II). Specific examples of the monomer that provides the structural unit of the general formula (I) include the following compounds.

[0020]

[Chemical 9]

[0021]

[Chemical 10]

[0022]

[Chemical 11]

[0023]

[Chemical 12]

[0024]

[Chemical 13]

[0025]

[Chemical 14]

[0026]

[Chemical 15]

[0027]

[Chemical 16]

[0028]

[Chemical 17]

[0029]

[Chemical 18]

[0030]

[Chemical 19]

[0031]

[Chemical 20]

[0032]

[Chemical 21]

[0033]

[Chemical formula 22]

[0034]

[Chemical formula 23]

[0035]

[Chemical formula 24]

[0036]

[Chemical 25]

[0037]

[Chemical formula 26]

[0038]

[Chemical 27]

[0039]

[Chemical 28]

[0040]

[Chemical 29]

[0041]

[Chemical 30]

[0042]

[Chemical 31]

[0043]

[Chemical 32]

[0044]

[Chemical 33]

[0045]

[Chemical 34]

[0046]

[Chemical 35]

[0047]

[Chemical 36]

[0048]

[Chemical 37]

[0049]

[Chemical 38]

Specific examples of the monomer giving the structural unit of the general formula (II) include, for example, t-butylcyclohexyl acrylate, t-butylcyclohexyl methacrylate, t-butylcyclohexyl-α-trifluoroacrylate, t-butyl. Cyclohexyl-α-trichloroacrylate, t-butylcyclohexyl-α-chloroacrylate, t-butylcyclohexyl-α-cyanoacrylate, isopropylcyclohexyl acrylate, isopropylcyclohexyl methacrylate, isopropylcyclohexyl-α-trifluoroacrylate, isopropylcyclohexyl-α-trichloro Acrylate, isopropylcyclohexyl-α-chloroacrylate, isopropylcyclohexyl-α-cyanoacrylate, isobornyl Acrylate, isobornyl methacrylate, isobornyl-α-cyanoacrylate, adamantyl methacrylate, adamantyl methacrylate, adamantyl-α-cyanoacrylate,
Dimethyl adamantyl methacrylate, dimethyl adamantyl methacrylate, dimethyl adamantyl-α-cyanoacrylate, dicyclopentanyl acrylate,
Examples thereof include dicyclopentanyl methacrylate, dimethyldicyclopentanyl acrylate and dimethyldicyclopentanyl methacrylate.

The copolymer used in the present invention may be a copolymer further containing another monomer copolymerizable with the above-mentioned monomer as a copolymerization component. The other monomer is not particularly limited as long as it is a copolymerizable monomer, but specific examples include acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate,
Acrylic acid derivatives such as glycidyl acrylate; Methacrylic acid derivatives such as methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and glycidyl methacrylate; acrylic acid amide derivatives, methacrylic acid amide derivatives, maleic acid derivatives, maleic anhydride Examples thereof include derivatives, vinyl acetate, vinyl pyridine, acrylonitrile, vinyl pyrrolidone, vinyl carbazole and the like. The above-mentioned other copolymerizable monomer can be copolymerized within the range (usually 0 to 50 mol%) so as not to impair the alkali developability.

The copolymer of the present invention can be obtained by a usual polymerization method such as radical polymerization or ionic polymerization, and the weight average molecular weight of the copolymer is 1,000 to 1,
Those in the range of, 000,000 are preferred. The molar ratio of the structural unit (I) to the structural unit (II) is usually 5:
95-95: 5, preferably 10: 90-90: 10,
More preferably, it is 30:70 to 70:30. If the proportion of the structural unit (I) is too small, the sensitivity and resolution are lowered, and conversely, if the proportion of the structural unit (II) is too small, K
Both are not preferable because the transmittance of the rF excimer laser light is lowered and the pattern shape is deteriorated.

(Alkali-soluble phenol resin) Examples of the alkali-soluble phenol resin used in the present invention include condensation reaction products of phenols and aldehydes, condensation reaction products of phenols and ketones, and vinylphenol resins. Examples thereof include polymers, isopropenylphenol-based polymers, hydrogenation reaction products of these phenolic resins, and the like.

Specific examples of the phenols include monovalent phenols such as phenol, cresol, xylenol, ethylphenol, propylphenol, butylphenol and phenylphenol; polyhydric compounds such as resorcinol, pyrocatechol, hydroquinone, bisphenol A and pyrogallol. Phenols; and the like. Specific examples of the aldehydes include formaldehyde, acetaldehyde, benzaldehyde, terephthalaldehyde and the like. Specific examples of the ketones include acetone, methyl ethyl ketone, diethyl ketone, diphenyl ketone and the like. These condensation reactions can be performed according to a conventional method.

The vinylphenol polymer is selected from a homopolymer of vinylphenol and a copolymer of vinylphenol and a component copolymerizable with vinylphenol. Specific examples of the copolymerizable component include acrylic acid, methacrylic acid, styrene, maleic anhydride, maleic imide, and their derivatives, vinyl acetate, acrylonitrile, and the like. The isopropenylphenol-based polymer is selected from isopropenylphenol homopolymers and copolymers with a component copolymerizable with isopropenylphenol. Specific examples of the copolymerizable component include acrylic acid,
Methacrylic acid, styrene, maleic anhydride, maleic imide, and derivatives thereof, vinyl acetate, acrylonitrile and the like can be mentioned.

The hydrogenation reaction of these phenolic resins can be carried out by any known method. The phenolic resin is dissolved in an organic solvent in the presence of a homogeneous or heterogeneous hydrogenation catalyst. , Can be achieved by introducing hydrogen. These alkali-soluble phenol resins may be used alone, or two or more kinds may be mixed and used. The addition amount of the alkali-soluble phenol resin (C) is usually 0 to 300 parts by weight, preferably 0 to 100 parts by weight with respect to 100 parts by weight of the copolymer (A).
Parts by weight.

The resist composition of the present invention may contain, for example, a copolymer of styrene and acrylic acid, methacrylic acid or maleic anhydride in order to improve developability, storage stability, heat resistance and the like, if necessary. A combination, a copolymer of an alkene and maleic anhydride, a vinyl alcohol polymer, a vinylpyrrolidone polymer, rosin, shellac and the like can be added. The addition amount of these optional components is usually 0 to 50 parts by weight, preferably 0 to 20 parts by weight, based on 100 parts by weight of the copolymer (A).

(1,2-naphthoquinonediazide compound)
In the present invention, a 1,2-naphthoquinonediazide compound is used as a compound capable of generating an acid upon irradiation with actinic rays (acid cleavable compound: PAG). Specific examples include 1,2-naphthoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid amide, 1,2-naphthoquinonediazide-4-sulfonic acid imide and the like. Quinone diazide-4-
Examples thereof include sulfonic acid compounds. Preferably 248
-Absorbance per ppm at 251 nm is 0.01
The compound 1,2-naphthoquinonediazide-4 is
-Sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid amide, and 1,2-naphthoquinonediazide-4-sulfonic acid imide are preferred.

Examples of the compound having an absorbance of 0.01 or less per ppm at 248 to 251 nm are alcohols such as methanol, ethanol, propanol and cyclohexanol; ethylene glycol,
Compounds having alcoholic hydroxyl groups consisting of diols such as propylene glycol and butanediol; phenols such as cresol and phloroglucinol; bisphenols such as bisphenol A and bisphenol F; chromones consisting of chromones, flavanones and catechins Examples thereof include compounds having a hydroxyl group; compounds having an amino group such as methylamine, ethylamine, ethylenediamine, aniline, and phenylenediamine; compounds having an imide group including succinimide, maleic acid imide, phthalic acid imide, and the like.

The 1,2-naphthoquinonediazide compound used in the present invention can be easily synthesized by a conventional method by reacting the above compound with 1,2-naphthoquinonediazide-4-sulfonic acid. The 1,2-naphthoquinonediazide compound is added in an amount of the copolymer (A) 10
It is usually 0.1 to 50 parts by weight, preferably 1 to 20 parts by weight, based on 0 parts by weight. If this addition amount is less than 0.1 parts by weight, it becomes virtually impossible to form a pattern, and conversely,
If the amount exceeds 50 parts by weight, a development residue tends to occur, which is inconvenient for the resist performance.

In the resist composition of the present invention, in order to improve sensitivity, resolution and process margin,
Other than the naphthoquinonediazide compound, an onium salt, a halogenated organic compound, a sulfonic acid derivative or the like, which is a compound capable of generating an acid upon irradiation with an actinic ray, can be added. Specific examples of onium salts include diazonium salts, ammonium salts, iodonium salts, sulfonium salts, phosphonium salts, arsonium salts, oxonium salts and the like.

The halogenated organic compound is not particularly limited as long as it is a halide of an organic compound, and various known compounds can be used. Specific examples include halogen-containing oxadiazole compounds and halogen-containing triazine compounds. , Halogen-containing acetophenone compound, halogen-containing benzophenone compound, halogen-containing sulfoxide compound, halogen-containing sulfone compound, halogen-containing thiazole compound, halogen-containing oxazole compound, halogen-containing trizole compound, halogen-containing 2-pyrone compound , Various compounds such as halogen-containing aliphatic hydrocarbon compounds, halogen-containing aromatic hydrocarbon compounds, other halogen-containing cyclic compounds, and sulfenyl halide compounds.

Further, as halogenated organic compounds, tris (2,3-dibromopropyl) phosphate, tris (2,3-dibromo-3-chloropropyl) phosphate, chlorotetrabromobutane, hexachlorobenzene, hexabromobenzene, hexa Bromocyclododecane, hexabromobiphenyl, tribromophenyl allyl ether, tetrachlorobisphenol A, tetrabromobisphenol A, bis (bromoethyl ether)
Tetrabromobisphenol A, bis (chloroethyl ether) tetrabromobisphenol A, tris (2,
3-dibromopropyl) isocyanurate, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxyethoxy-3,5
Halogen-containing flame retardants such as -dibromophenyl) propane; dichlorodiphenyltrichloroethane, benzenehexachloride, pentachlorophenol, 2,4,6
-Trichlorophenyl-4-nitrophenyl ether,
2,4-dichlorophenyl-3'-methoxy-4'-nitrophenyl ether, 2,4-dichlorophenoxyacetic acid, 4,5,6,7-tetrachlorophthalide, 1,1
-Bis (4-chlorophenyl) ethanol, 1,1-
Bis (4-chlorophenyl) -2,2,2-trichloroethanol, ethyl-4,4-dichlorobenzilate, 2,4,5,4'-tetrachlorodiphenyl sulfide, 2,4,5,4 ' -Organic chloro pesticides such as tetrachlorodiphenyl sulfone are also included. Specific examples of the sulfonic acid derivative include sulfonic acid ester,
Examples thereof include sulfonic acid amide and sulfonic acid imide. The addition amount of these components is usually 0 to 20 parts by weight, preferably 1 to 1 with respect to 100 parts by weight of the copolymer (A).
0 parts by weight.

(Resist Composition) The resist composition of the present invention is usually used by dissolving each of the above components in a solvent in order to form a resist film by coating on a substrate. Examples of the solvent include ketones such as acetone, methyl ethyl ketone, cyclohexanone, cyclopentanone, cycloheptanone, butyrolactone and 2-heptanone; n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, t-butyl alcohol and the like. Alcohols; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, dioxane and other ethers; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether and other alcohol ethers; propyl formate, formic acid Butyl, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl acetate, ethyl acetate, etc. Esters; 2-oxy-propionic acid, 2- oxy propionate, 2-methoxypropionate, methyl 2-methoxy propionate, 2
-Monooxycarboxylic acid esters such as ethyl ethoxypropionate; cellosolve esters such as cellosolve acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propyl cellosolve acetate, butyl cellosolve acetate; propylene glycol,
Propylene glycols such as propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether; diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, etc. Diethylene glycols; halogenated hydrocarbons such as trichloroethylene; aromatic hydrocarbons such as toluene and xylene; polar solvents such as dimethylacetamide, dimethylformamide, N-methylacetamide, N-methylpyrrolidone; These solvents may be used alone or in combination of two or more. The resist composition of the present invention may contain compatible additives such as a surfactant, a storage stabilizer, a sensitizer, a striation inhibitor, a plasticizer, and an antihalation agent, if necessary. it can.

As the developing solution for the resist composition of the present invention, an aqueous alkali solution is usually used.
Inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium silicate, ammonia; ethylamine,
Primary amines such as propylamine; diethylamine,
Secondary amines such as dipropylamine; tertiary amines such as trimethylamine and triethylamine; alcohol amines such as diethylethanolamine and triethanolamine; tetramethylammonium hydroxide,
Quaternary ammonium salts such as tetraethylammonium hydroxide, trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammonium hydroxide, trimethylhydroxyethylammonium hydroxide; and the like. Further, if necessary, in the alkaline aqueous solution, for example, methanol,
An appropriate amount of a water-soluble organic solvent such as ethanol, propanol, or ethylene glycol, a surfactant, a storage stabilizer, a resin dissolution inhibitor, or the like can be added.

The resist composition of the present invention can be applied to the surface of a substrate such as a silicon wafer by a conventional method using the solvent solution thereof, and then the solvent is dried and removed to form a resist film. As a coating method, spin coating is particularly preferred. Also, the exposure is deep UV,
A fine pattern can be formed by using KrF excimer laser light, i-line (365 nm), or the like as a light source. It is preferable to perform a heat treatment (post-exposure bake) after the exposure, because the reaction is promoted and the sensitivity is improved and stabilized.

In the resist composition of the present invention, the copolymer (A) is capable of forming an acid upon irradiation with an actinic ray.
Under the action of an acid derived from the 2-naphthoquinonediazide compound (B), the solubility of the irradiated portion changes. The resist composition of the present invention acts as a positive resist by using an alkaline developer. In the resist composition of the present invention, since the copolymer (A) used has the structural unit (I), not only the sensitivity and resolution are excellent, but also the structural unit (II) is contained, so that the KrF excimer laser light is used. The transmittance of (248 nm) is high and the pattern shape is good. Further, when an alkali-soluble phenol resin is used in combination, resist characteristics such as sensitivity and resolution are improved.

[0068]

EXAMPLES The present invention will be described in more detail with reference to the following examples. Parts and% in each example are based on weight unless otherwise specified.

Example 1 Copolymer of compound (20) and isobornyl methacrylate (Mw = 26000, copolymerization molar ratio = 7/3) 100 parts Bisphenol A 1,2-naphthoquinonediazide-4-sulfone Acid ester 15 parts Fluorosurfactant 0.01 part Propylene glycol monomethyl ether acetate 380 parts These are mixed and dissolved, and filtered with a tetrafluoroethylene filter (Teflon filter manufactured by Millipore) having a pore size of 0.1 μm to obtain a resist solution. Was prepared.

The above resist solution was applied onto a silicon wafer with a spinner and then baked at 90 ° C. for 90 seconds to form a resist film having a thickness of 1.0 μm. The wafer on which this resist film is formed is used as a KrF excimer laser stepper NS.
Exposure was performed using R1755EX8A (NA = 0.45, manufactured by Nikon Corporation) and a test reticle, and post exposure bake (PEB) was performed at 110 ° C. for 60 seconds. Then, an aqueous solution of tetramethylammonium hydroxide (concentration: 2.38)
%) At 23 ° C. for 1 minute to develop a positive pattern.

The sensitivity was evaluated to be 50 mJ / cm ² , and the film thickness of the pattern was measured with a film thickness meter (Alphastep 200, manufactured by Tenko Co.) to be 0.93 μm.
When the wafer on which the pattern was formed was taken out and observed with an electron microscope, a 0.40 μm pattern was resolved. This resist was applied on a quartz plate to a film thickness of 1 μm, and the transmittance at 248 nm was measured and found to be 38%.

Comparative Example 1 Instead of the copolymer of Example 1, resin poly (t) described in Japanese Patent Publication No. 27660/1990 was used.
-Butoxycarbonyloxystyrene) (Mw = 280
A resist solution was prepared in the same manner as in Example 1 except that (00) was used. When the sensitivity of this resist was evaluated in the same manner as in Example 1, it was 45 mJ / cm ² , and when the resolution was evaluated, a pattern of 0.45 μm was obtained. This resist is applied to a quartz plate so as to have a thickness of 1 μm, and 248
When the transmittance in nm was measured, it was 21% or less.

Example 2 Copolymer of Example 1 100 parts 1,2-naphthoquinonediazide-4-sulfonic acid ester of bisphenol A 13 parts Triphenylsulfonium triflate 2 parts Fluorosurfactant 0.01 parts Propylene glycol monomethyl ether acetate 460 parts These were mixed and dissolved, and filtered with a 0.1 μm Teflon filter (manufactured by Millipore) to prepare a resist solution.

The above resist solution was applied onto a silicon wafer by a spinner and then baked at 110 ° C. for 90 seconds to form a resist film having a thickness of 0.7 μm. The wafer on which this resist film is formed is used as a KrF excimer laser stepper N
SR1755EX8A (NA = 0.45, manufactured by Nikon Corporation)
Was exposed using a test reticle, and post-exposure baking was performed at 100 ° C. for 60 seconds. Then, it was developed with a tetramethylammonium hydroxide aqueous solution at 23 ° C. for 1 minute by a dipping method to obtain a positive pattern. The sensitivity was evaluated to be 30 mJ / cm ² , and the film thickness of the pattern was measured with a film thickness meter (manufactured by Tenko Co., Alpha Step 200) to be 0.93 μm. The patterned wafer was taken out and observed with an electron microscope. As a result, it was 0.35 μm.
Pattern was resolved.

Example 3 Copolymer of Example 1 100 parts 1,2-naphthoquinonediazide-4-sulfonic acid ester of cumylphenol 15 parts Fluorosurfactant 0.01 part Propylene glycol monomethyl ether acetate 360 Parts These were mixed and dissolved, and filtered with a 0.1 μm Teflon filter (manufactured by Millipore) to prepare a resist solution.

The above resist solution was applied onto a silicon wafer by a spinner and then baked at 90 ° C. for 90 seconds to form a resist film having a thickness of 1.0 μm. The wafer on which this resist film is formed is used as a KrF excimer laser stepper NS.
Exposure was performed using R1755EX8A (NA = 0.45, manufactured by Nikon Corporation) and a test reticle, and post-exposure baking was performed at 110 ° C. for 60 seconds. Then, it was developed with a tetramethylammonium hydroxide aqueous solution at 23 ° C. for 1 minute by a dipping method to obtain a positive pattern. Evaluating sensitivity 4
The film thickness of the pattern was 6 mJ / cm ² , and it was found to be 0.
It was 93 μm. When the wafer on which the pattern was formed was taken out and observed with an electron microscope, a 0.35 μm pattern was resolved.

Example 4 Copolymer of Compound (8) and Adamantyl Methacrylate (Mw = 20,000, Copolymerization Molar Ratio = 8/2) 100 parts 1,2-naphthoquinonediazide-4-sulfonic acid ester of bisphenol P 15 parts Fluorosurfactant 0.01 part Propylene glycol monomethyl ether acetate 450 parts These were mixed and dissolved, and filtered with a 0.1 μm Teflon filter (manufactured by Millipore) to prepare a resist solution.

The above resist solution was applied on a silicon wafer by a spinner and then baked at 90 ° C. for 90 seconds to form a resist film having a thickness of 0.7 μm. The wafer on which this resist film is formed is used as a KrF excimer laser stepper NS.
Exposure was performed using R1755EX8A (NA = 0.45, manufactured by Nikon Corporation) and a test reticle, and post-exposure baking was performed at 110 ° C. for 60 seconds. Then, it was developed with a tetramethylammonium hydroxide aqueous solution at 23 ° C. for 1 minute by a dipping method to obtain a positive pattern. The sensitivity was evaluated to be 62 mJ / cm ² , and the film thickness of the pattern was measured with a film thickness meter (manufactured by Tenko Co., Alpha Step 200) to be 0.62 μm. The patterned wafer was taken out and observed with an electron microscope. As a result, it was 0.35 μm.
Pattern was resolved.

Example 5 Copolymer of Example 4 100 parts 1,2-naphthoquinonediazide-4-sulfonic acid ester of bisphenol P 12 parts Benzenesulfonic acid ester of bisphenol A 5 parts Fluorosurfactant 0. 01 parts Propylene glycol monomethyl ether acetate 350 parts These were mixed and dissolved, and filtered through a 0.1 μm Teflon filter (manufactured by Millipore) to prepare a resist solution.

The above resist solution was applied on a silicon wafer by a spinner and then baked at 110 ° C. for 90 seconds to form a resist film having a thickness of 1.0 μm. The wafer on which this resist film is formed is used as a KrF excimer laser stepper N
SR1755EX8A (NA = 0.45, manufactured by Nikon Corporation)
Was exposed using a test reticle, and post-exposure baking was performed at 100 ° C. for 60 seconds. Then, it was developed with a tetramethylammonium hydroxide aqueous solution at 23 ° C. for 1 minute by a dipping method to obtain a positive pattern. The sensitivity was evaluated to be 46 mJ / cm ² , and the film thickness of the pattern was measured with a film thickness meter (manufactured by Tenko Co., Alpha Step 200) to be 0.92 μm. The patterned wafer was taken out and observed with an electron microscope.
The pattern of m was resolved.

Example 6 Copolymer of Compound (7) and Dicyclopentanyl Methacrylate (Mw = 18,000, Copolymerization Molar Ratio = 7/3) 100 parts 1,2-naphthoquinonediazide of p-cumylphenol -4-Sulfonic acid ester 15 parts Triphenylsulfonium triflate 3 parts Fluorosurfactant 0.01 part Propylene glycol monomethyl ether acetate 450 parts These are mixed and dissolved to obtain a 0.1 μm Teflon filter (Millipore). And filtered to prepare a resist solution.

The above resist solution was applied onto a silicon wafer by a spinner and then baked at 110 ° C. for 90 seconds to form a resist film having a thickness of 0.7 μm. The wafer on which this resist film is formed is used as a KrF excimer laser stepper N
SR1755EX8A (NA = 0.45, manufactured by Nikon Corporation)
Was exposed using a test reticle, and post-exposure baking was performed at 100 ° C. for 60 seconds. Then, it was developed with a tetramethylammonium hydroxide aqueous solution at 23 ° C. for 1 minute by a dipping method to obtain a positive pattern. The sensitivity was evaluated to be 18 mJ / cm ² , and the film thickness of the pattern was measured with a film thickness meter (manufactured by Tenko Co., Alpha Step 200) to be 0.92 μm. The patterned wafer was taken out and observed with an electron microscope. As a result, it was 0.35 μm.
Pattern was resolved.

Example 7 Copolymer of Compound (19) and t-Butylcyclohexyl Methacrylate (Mw = 32000, Copolymerization Molar Ratio = 6/4) 100 parts Bisphenol A 1,2-naphthoquinonediazide-4- Sulfonic acid ester 12 parts p-Toluenesulfonic acid phenyl ester 3 parts Fluorosurfactant 0.01 part Propylene glycol monomethyl ether acetate 450 parts These are mixed and dissolved, and then a 0.1 μm Teflon filter (Millipore) is used. It filtered and prepared the resist solution.

The above resist solution was applied onto a silicon wafer by a spinner and then baked at 110 ° C. for 90 seconds to form a resist film having a thickness of 0.7 μm. The wafer on which this resist film is formed is used as a KrF excimer laser stepper N
SR1755EX8A (NA = 0.45, manufactured by Nikon Corporation)
Was exposed using a test mask, and post-exposure baking was performed at 100 ° C. for 60 seconds. Then, it was developed with a tetramethylammonium hydroxide aqueous solution at 23 ° C. for 1 minute by a dipping method to obtain a positive pattern. The sensitivity was evaluated to be 38 mJ / cm ² , and the film thickness of the pattern was measured with a film thickness meter (manufactured by Tenko Co., Alpha Step 200) to be 0.64 μm. The patterned wafer was taken out and observed with an electron microscope. As a result, it was 0.35 μm.
Pattern was resolved.

Example 8 Copolymer of Compound (8) and Isobornyl Methacrylate (Mw = 28,000, Copolymerization Molar Ratio = 6/4) 100 parts Bisphenol A 1,2-naphthoquinonediazide-4-sulfone Acid ester 13 parts Benzenesulfonic acid phenyl ester 3 parts Fluorosurfactant 0.01 part Propylene glycol monomethyl ether acetate 360 parts These are mixed and dissolved, and filtered with a 0.1 μm Teflon filter (Millipore), A resist solution was prepared.

The above resist solution was applied onto a silicon wafer with a spinner and then baked at 110 ° C. for 90 seconds to form a resist film having a thickness of 1.0 μm. The wafer on which this resist film is formed is used as a KrF excimer laser stepper N
SR1755EX8A (NA = 0.45, manufactured by Nikon Corporation)
Was exposed using a test mask, and post-exposure baking was performed at 100 ° C. for 60 seconds. Then, it was developed with a tetramethylammonium hydroxide aqueous solution at 23 ° C. for 1 minute by a dipping method to obtain a positive pattern. The sensitivity was evaluated to be 40 mJ / cm ² , and the film thickness of the pattern was measured to be 0.63 μm with a film thickness meter (manufactured by Tenko Co., Alpha Step 200). The patterned wafer was taken out and observed with an electron microscope to find that it was 0.40 μm.
Pattern was resolved.

Example 9 Copolymer of Example 8 100 parts Hydrogenated polyvinylphenol 15 parts (Mw = 5000, hydrogenation rate = 10%) 1,2-naphthoquinonediazide-4-sulfonic acid ester of bisphenol A 13 parts Benzenesulfonic acid phenyl ester 2 parts Fluorosurfactant 0.01 part Propylene glycol monomethyl ether acetate 480 parts Mixing and dissolving these, filtering with a 0.1 μm Teflon filter (Millipore), resist solution Was prepared.

The above resist solution was applied onto a silicon wafer with a spinner and then baked at 110 ° C. for 90 seconds to form a resist film having a thickness of 0.7 μm. The wafer on which this resist film is formed is used as a KrF excimer laser stepper N
SR1755EX8A (NA = 0.45, manufactured by Nikon Corporation)
Was exposed using a test mask, and post-exposure baking was performed at 100 ° C. for 60 seconds. Then, it was developed with a tetramethylammonium hydroxide aqueous solution at 23 ° C. for 1 minute by a dipping method to obtain a positive pattern. The sensitivity was evaluated to be 32 mJ / cm ² , and the film thickness of the pattern was measured to be 0.63 μm by a film thickness meter (manufactured by Tenko Co., Alpha Step 200). The patterned wafer was taken out and observed with an electron microscope. As a result, it was 0.35 μm.
Pattern was resolved.

[0089]

According to the present invention, the resist characteristics such as sensitivity, resolution, etching resistance, and storage stability are excellent,
Further, since the transmittance is improved by the exposure, the resist pattern is excellent in shape, and a resist material suitable for lithography using deep ultraviolet rays having a short wavelength or KrF excimer laser light is provided. The resist composition of the present invention is particularly suitable as a positive resist for fine processing of semiconductor devices.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03F 7/039 501 H01L 21/027

Claims (4)

[Claims] 1. A copolymer (A) having a structural unit represented by the following general formulas (I) and (II) in the molecular chain, and a 1,2-naphthoquinonediazide compound (B). A resist composition comprising: [Chemical 1] [In the formula, R ¹ and R ² are the same or different from each other and are a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a substituted alkyl group having 1 to 5 carbon atoms, a halogen atom, or a cyano group;
^3, linear acetal group, cyclic acetal group, a carbonate group, or -OR ^4. However, R ⁴ is Or [Chemical 3] Is. (However, in these formulas, R ⁷ , R ⁸ , R ⁹ , R
¹⁰ , R ¹¹ and R ¹² are each independently a chain alkyl group, a substituted chain alkyl group, a branched alkyl group, a substituted branched alkyl group, a cyclic alkyl group, a substituted cyclic alkyl group,
It represents an alkenyl group, a substituted alkenyl group, an aryl group, a substituted aryl group, an aralkyl group, or a substituted aralkyl group, and of these, R ¹⁰ and R ¹¹ may be a hydrogen atom. )]. ] [Chemical 4] [In the formula, R ⁵ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a substituted alkyl group having 1 to 5 carbon atoms, a halogen atom, or a cyano group, and R ⁶ is a cyclic group having 5 to 16 carbon atoms. It is an alkyl group or a substituted cyclic alkyl group having 5 to 16 carbon atoms. ] 2. The resist composition according to claim 1, further comprising an alkali-soluble phenol resin (C). 3. The resist composition according to claim 1, wherein the 1,2-naphthoquinonediazide compound (B) is used in combination with another compound capable of generating an acid upon irradiation with actinic rays. 4. Alkali-soluble phenolic resin (C)
The resist composition according to claim 2, wherein is a hydrogen-soluble phenol resin soluble in alkali.