JP2626479B2 - Positive resist composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive resist composition, and more particularly to a positive resist composition for fine processing required for manufacturing semiconductor devices, magnetic bubble memory devices, integrated circuits and the like. is there.

[0002]

2. Description of the Related Art When manufacturing semiconductors, a resist is applied to the surface of a silicon wafer to form a photosensitive film, which is irradiated with light to form a latent image, and then developed to form a negative or positive image. 2. Description of the Related Art A semiconductor element is formed by a lithography technique. Conventionally, as a resist composition for forming a semiconductor element, a negative resist comprising a cyclized polyisoprene and a bisazide compound has been known. However, since this negative resist is developed with an organic solvent, it swells greatly and has a limitation in resolution, and thus has a disadvantage that it cannot cope with the manufacture of a highly integrated semiconductor. On the other hand, it is considered that the positive resist composition is superior in resolution to the negative resist composition, and therefore can sufficiently cope with high integration of semiconductors.

At present, a positive resist composition generally used in this field comprises a novolak resin and a quinonediazide compound. However, conventional positive resist compositions have not always achieved satisfactory results in various properties such as sensitivity, resolution, residual film ratio, heat resistance, and storage stability, and there is a strong demand for improved performance. . Especially,
Sensitivity is important for improving the productivity of semiconductors, and it is strongly desired to increase the sensitivity of a positive resist composition. For this purpose, various compounds are added in addition to the novolak resin and the quinonediazide compound, which are base components of the positive resist composition. Examples of the compound added for increasing the sensitivity, ie, a sensitizer, include a nitrogen heterocyclic compound such as a halogenated benzotriazole derivative (JP-A-58-37641) and a cyclic acid anhydride. (JP-B-56-30850). However, the addition of these sensitizers eliminates the difference in solubility between exposed and unexposed areas, resulting in a decrease in the residual film ratio, deterioration in resolution, and plasticization of the novolak resin by the sensitizer. There arises a problem such as a decrease in heat resistance due to the activating effect.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks of the prior art and to provide excellent characteristics such as sensitivity, resolution, residual film ratio, heat resistance and storage stability, especially 1 μm or less. It is an object of the present invention to provide a high-sensitivity positive resist composition suitable for fine processing. This object of the present invention is achieved by incorporating a specific phenol compound into a positive resist composition containing an alkali-soluble phenol resin and a quinonediazide sulfonic acid ester-type photosensitizer.

[0005]

Thus, according to the present invention, (A) an alkali-soluble phenol resin, (B) a quinonediazide sulfonic acid ester-based photosensitizer of a compound represented by the following formula (I):

[0006]

Embedded image And a compound represented by the following general formula (II)

[0007]

Embedded image (R _{1 to} R ₇ are a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms,
Alternatively, it is a substituted or unsubstituted alkoxy group having 1 to 3 carbon atoms, which may be the same or different.
R ₈ is a hydrogen atom or an alkyl group. ) Is provided. Hereinafter, the present invention will be described in detail.

Alkali-Soluble Phenolic Resin Examples of the alkali-soluble phenol resin used in the present invention include a condensation reaction product of a phenol and an aldehyde, a condensation reaction product of a phenol and a ketone, and a vinylphenol polymer. And isopropenylphenol-based polymers, and hydrogenation products of these phenolic resins.

Specific examples of the phenols used herein include monovalent phenols such as phenol, cresol, xylenol, ethylphenol, propylphenol, butylphenol, and phenylphenol; resorcinol, pyrocatechol, hydroquinone, bisphenol A, pyrogallol, and the like. Polyhydric phenols; and the like.

Specific examples of the aldehyde used here include formaldehyde, acetaldehyde, benzaldehyde, terephthalaldehyde and the like. Specific examples of the ketones used here include acetone, methyl ethyl ketone, diethyl ketone, diphenyl ketone, and the like. These condensation reactions can be performed according to a conventional method such as bulk polymerization or solution polymerization.

The vinylphenol-based 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, vinyl acetate, acrylonitrile, and derivatives thereof.

The isopropenylphenol-based polymer is selected from a homopolymer of isopropenylphenol and a copolymer of isopropenylphenol with a copolymerizable component. Specific examples of the copolymerizable component include acrylic acid, methacrylic acid, styrene, maleic anhydride, maleic imide, vinyl acetate, acrylonitrile, and derivatives thereof.

[0013] The hydrogenation reaction of these phenolic resins can be carried out by any known method. The phenolic resin is dissolved in an organic solvent, and is dissolved in the presence of a homogeneous or heterogeneous hydrogenation catalyst. , Can be achieved by introducing hydrogen. As these alkali-soluble phenol resins, those whose molecular weight distribution is controlled by reprecipitation separation or the like can be used. In addition, these phenol resins may be used alone or in combination of two or more.

The positive resist composition of the present invention may contain, for example, styrene and acrylic acid, methacrylic acid or maleic anhydride, if necessary, in order to improve developability, storage stability, heat resistance and the like. Copolymers, copolymers of alkenes and maleic anhydride, vinyl alcohol polymers, vinylpyrrolidone polymers, rosin, shellac and the like can be added. The addition amount is 0 to 50 parts by weight, preferably 5 to 20 parts by weight, based on 100 parts by weight of the alkali-soluble phenol resin.

Quinonediazidesulfonic acid ester type photosensitive
Agent The photosensitive agent used in the present invention is not particularly limited as long as it is a quinonediazidesulfonic acid ester of the compound represented by the formula (I). As a specific example, the ester moiety is 1,2-benzoquinonediazide-4
-Sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,1-naphthoquinonediazide-4-sulfonic acid ester, 2,1-naphthoquinonediazide And sulfonic acid esters of quinonediazide derivatives and the like.

The quinonediazidesulfonic acid ester can be generally synthesized by an esterification reaction between a compound having a hydroxyl group and a quinonediazidesulfonic acid compound [Photosensitive Polymers by Mototaro Nagamatsu and Hideo Inui (198).
0) Kodansha (Tokyo) etc.], for example, according to a conventional method, a quinonediazidesulfonic acid compound is converted to sulfonyl chloride with chlorosulfonic acid, and this is condensed with the compound represented by the above formula (I). .

The compound represented by the formula (I) includes
A compound commercially available under the trade name Trisphenol PA (manufactured by Mitsui Petrochemical Co., Ltd.) can be used. The photosensitive agent in the present invention may be used alone or in combination of two or more. A quinonediazidesulfonic acid ester of a hydroxyl group-containing compound other than the compound represented by the formula (I) may be used in combination as a small component. The amount of the photosensitive agent is usually 1 to 100 parts by weight, preferably 3 to 40 parts by weight, per 100 parts by weight of the alkali-soluble phenol resin.
Parts by weight. If the amount is less than 1 part by weight, it is impossible to form a pattern. If the amount exceeds 100 parts by weight, an afterimage is liable to occur.

Sensitizer The sensitizer used in the present invention has the general formula (I)
There are no particular restrictions on the compound represented by I). Specific examples of the compound represented by the general formula (II) include the following.

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[0042]

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[0043]

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The sensitizer in the present invention may be used alone or in combination of two or more. The amount of the sensitizer is usually 1 to 100 parts by weight, preferably 2 to 100 parts by weight, based on 100 parts by weight of the alkali-soluble phenol resin.
50 parts by weight. If the amount exceeds 100 parts by weight, the rate of residual film decreases sharply, making pattern formation difficult.

Other Components The positive resist composition of the present invention is used after being dissolved in a solvent. Examples of the solvent include ketones such as acetone, methyl ethyl ketone, cyclohexanone and cyclopentanone; n-propyl alcohol, iso Alcohols such as -propyl alcohol, n-butyl alcohol and cyclohexanol; ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether and dioxane; alcohol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; propyl formate; Butyl formate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl butyrate, ethyl butyrate,
Esters such as methyl lactate and ethyl lactate; cellosolve esters such as cellosolve acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propyl cellosolve acetate and butyl cellosolve acetate; propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether acetate, propylene glycol Propylene glycols such as monomethyl ether acetate, propylene glycol monoethyl ether acetate and propylene glycol monobutyl ether; diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ether Diethylene glycols such as ethers, halogenated hydrocarbons such as trichlorethylene; toluene, aromatic hydrocarbons such as xylene;
Polar solvents such as dimethylacetamide, dimethylformamide, and N-methylacetamide; and the like.
These may be used alone or in combination of two or more. The positive resist composition of the present invention contains surfactants, storage stabilizers, and other compatible additives such as sensitizers, striation inhibitors, plasticizers, and antihalation agents as necessary. Can be done.

[0046] As the developing solution in the developing solution is called a positive resist composition of the present invention uses an alkaline aqueous solution, and specific examples include sodium hydroxide, potassium hydroxide, sodium silicate, inorganic alkalis such as ammonium, ethylamine And primary amines such as propylamine; secondary amines such as diethylamine and dipropylamine; tertiary amines such as trimethylamine and triethylamine; alcohol amines such as diethylethanolamine and triethanolamine;
Quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammonium hydroxide, and trimethylhydroxyethylammonium hydroxide; and the like. If necessary, a suitable amount of a water-soluble organic solvent such as methanol, ethanol, propanol, or ethylene glycol, a surfactant, a storage stabilizer, a resin dissolution inhibitor, or the like can be added to the above-mentioned alkali water-soluble substance.

[0047]

The present invention will be described more specifically with reference to the following examples.

Example 1 Novolak resin 100 obtained by mixing m-cresol and p-cresol at a molar ratio of 7: 3, adding formalin thereto, and condensing by an ordinary method using an oxalic acid catalyst.
Parts by weight, 35 parts by weight of a quinonediazidesulfonic acid ester in which 90% of trisphenol PA (manufactured by Mitsui Petrochemical Co., Ltd.) is an ester of 1,2-naphthoquinonediazide-5-sulfonic acid, and a compound represented by the formula (9) Sensitizer)
7 parts by weight were dissolved in 350 parts by weight of ethyl cellosolve acetate, and filtered through a 0.1 μm polytetrafluoroethylene (hereinafter abbreviated as PTFE) filter to prepare a resist solution.

The resist solution was applied on a silicon wafer by a coater and baked at 100 ° C. for 90 seconds to form a resist film having a thickness of 1.17 μm. This wafer is used as an i-line stepper NSR-1505i6A (manufactured by Nikon Corporation,
Exposure was performed using a test reticle (NA = 0.45). Next, the wafer was post-exposed at 110 ° C. for 60 seconds, and then developed with a 2.38% aqueous tetramethylammonium hydroxide solution at 23 ° C. for 1 minute by a paddle method to obtain a positive pattern. When the wafer on which the pattern was formed was taken out and the sensitivity was evaluated, it was 140 mJ / cm ^2. Observation with an electron microscope revealed that a line and space of 0.40 μm had been resolved. The film thickness of the pattern was 1.15 μm as measured by a film thickness meter Alpha Step 200 (manufactured by Tenko).

Example 2 Novolak resin 100 obtained by mixing m-cresol and p-cresol at a molar ratio of 5: 5, adding formalin thereto, and condensing by an ordinary method using an oxalic acid catalyst.
95 parts by weight of 2,3,4,4'-tetrahydroxybenzophenone is 1,2-naphthoquinonediazide-5
Quinonediazide compound 14 which is an ester of sulfonic acid
18 parts by weight of a quinonediazide compound in which 90% of trisphenol PA (manufactured by Mitsui Petrochemical) is an ester of 1,2-naphthoquinonediazide-4-sulfonic acid,
And 10 parts by weight of the compound (sensitizer) represented by the formula (12) are dissolved in 380 parts by weight of ethyl lactate, and then 0.1 μm
Was filtered through a PTFE filter to prepare a resist solution.

The resist solution was applied on a silicon wafer by a coater and baked at 100 ° C. for 90 seconds to form a resist film having a thickness of 1.17 μm. This wafer is used as an i-line stepper NSR-1505i6A (manufactured by Nikon Corporation,
Exposure was performed using a test reticle (NA = 0.45). Next, the wafer was post-exposed at 110 ° C. for 60 seconds, and then developed with a 2.38% aqueous tetramethylammonium hydroxide solution at 23 ° C. for 1 minute by a paddle method to obtain a positive pattern. When the wafer on which the pattern was formed was taken out and the sensitivity was evaluated, it was 120 mJ / cm ^2. Observation with an electron microscope revealed that a line and space of 0.40 μm had been resolved. When the film thickness of the pattern was measured by a film thickness meter Alpha Step 200, it was 1.14 μm.

Example 3 Novolak resin 100 obtained by mixing m-cresol and p-cresol at a molar ratio of 5: 5, adding formalin thereto, and condensing by an ordinary method using an oxalic acid catalyst.
28 parts by weight of a quinonediazide compound in which 75% of trisphenol PA (manufactured by Mitsui Petrochemical) is an ester of 1,2-naphthoquinonediazide-4-sulfonic acid,
And 10 parts by weight of the compound (sensitizer) represented by the formula (12) are dissolved in 380 parts by weight of ethyl lactate, and then 0.1 μm
Was filtered through a PTFE filter to prepare a resist solution.

The resist solution was applied on a silicon wafer by a coater, and baked at 100 ° C. for 90 seconds to form a resist film having a thickness of 1.17 μm. This wafer is used as an i-line stepper NSR-1505i6A (manufactured by Nikon Corporation,
Exposure was performed using a test reticle (NA = 0.45). Next, the wafer was post-exposed at 110 ° C. for 60 seconds, and then developed with a 2.38% aqueous tetramethylammonium hydroxide solution at 23 ° C. for 1 minute by a paddle method to obtain a positive pattern. When the wafer on which the pattern was formed was taken out and the sensitivity was evaluated, it was 160 mJ / cm ^2. Observation with an electron microscope revealed that a 0.40 μm line & space had been resolved. The film thickness of the pattern was 1.16 μm when measured by a film thickness meter Alpha Step 200.

[0054]

The positive resist composition of the present invention is excellent in sensitivity, resolution, residual film ratio, heat resistance, storage stability and the like, and is therefore particularly useful for fine processing of 1 μm or less.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takamasa Yamada 1-1-2, Yakko, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture, Japan Zeon Corporation Research and Development Center (56) References JP-A-1-189644 (JP, A) JP-A-2-27555 (JP, A) JP-A-3-48249 (JP, A) JP-A-3-200252 (JP, A) JP-A-5-27446 (JP, A)

Claims (1)

(57) [Claims] (A) an alkali-soluble phenolic resin,
(B) a quinonediazidesulfonic acid ester-based photosensitizer of a compound represented by the following formula (I): And a compound represented by the following general formula (II): (R _{1 to} R ₇ are a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms,
Alternatively, it is a substituted or unsubstituted alkoxy group having 1 to 3 carbon atoms, which may be the same or different.
R ₈ is a hydrogen atom or an alkyl group. A positive resist composition comprising: