JP3275501B2 - 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. .

[0002]

2. Description of the Related Art In order to form a fine pattern using a resist, a solution containing a photosensitive material (resist composition) is applied on a substrate and dried to form a photosensitive film.
Irradiation with actinic rays forms a latent image, which is then developed to create a negative or positive image. In order to manufacture a semiconductor device by microfabrication using a resist, usually, a silicon wafer is used as a substrate, an image (pattern) is formed by the above lithography technique, and then the resist remaining on the substrate is used as a protective film for etching. After that, the resist film is removed. The positive resist, giving a positive image an irradiated portion of the photosensitive film is solubility increases in the developer than the unexposed regions, the negative type resist, solubility of the irradiated portion of the photosensitive film is reduced To give a negative image.

Conventionally, as a resist composition for forming a semiconductor device, for example, a negative resist comprising a cyclized polyisoprene and a bisdiazide compound has been known. However, since this negative resist is developed with an organic solvent, it has a disadvantage that it cannot cope with the manufacture of a highly integrated semiconductor because it has a large swelling and a limited resolution. Further, a negative resist containing polyglycidyl methacrylate has high sensitivity but is inferior in resolution and dry etching properties.

On the other hand, it is considered that a positive resist composition is superior in resolution to this negative resist composition and can sufficiently cope with high integration of semiconductors.
Currently, 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 obtained satisfactory results in various properties such as sensitivity, residual film ratio, resolution, heat resistance, and storage stability, and are required to improve performance.

Recently, it has been proposed to use quinonediazide sulfonic acid esters of various phenolic compounds as a photosensitizer in a positive resist containing an alkali-soluble phenol resin and a photosensitizer (Japanese Patent Laid-Open No. Hei 2 (1990) -1990).
296248, JP-A-2-296249, JP-A-4
-502519). However, the positive resist compositions specifically disclosed in these documents have somewhat insufficient sensitivity and residual film ratio, and further improvement is required.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a positive resist composition having excellent characteristics such as sensitivity, residual film ratio, resolution, heat resistance and storage stability, and particularly suitable for fine processing of 1 μm or less. To provide things. The present inventors have conducted intensive studies to overcome the problems of the prior art, and as a result, in a positive resist composition containing an alkali-soluble phenol resin and a photosensitizer, a positive resist composition having a phenolic hydroxyl group as the photosensitizer. It has been found that the above object can be achieved by using an ester of the compound (phenol compound) and a quinonediazidesulfonic acid compound.

The phenolic compound used in the present invention has a specific selected structure having four aromatic rings each having one OH group. That is not done. By using this phenol compound, it is possible to obtain a positive resist excellent in resolution, in particular, as compared with the positive resist specifically disclosed in the above publications.
The positive resist composition of the present invention has an improved residual film ratio. Of course, this positive resist composition has good sensitivity, heat resistance, storage stability, dry etching resistance and the like. The present invention has been completed based on these findings.

[0008]

Thus, according to the present invention, in a positive resist composition containing an alkali-soluble phenol resin and a photosensitizer, a phenol compound represented by the following general formula (I) is used as the photosensitizer. There is provided a positive resist composition comprising a quinonediazidesulfonic acid ester.

[0009]

Embedded image (In the formula, R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ^{3 to} R ⁶ are an alkyl group having 1 to 4 carbon atoms.)

Hereinafter, the present invention will be described in detail. (Alkali-soluble phenol resin) Examples of the alkali-soluble phenol resin used in the present invention include a condensation reaction product of phenols and aldehydes,
Examples include a condensation reaction product of a phenol and a ketone, a vinylphenol-based polymer, an isopropenylphenol-based polymer, and a hydrogenation reaction product of these phenol resins.

Specific examples of the phenols used herein include monovalent phenols such as phenol, cresol, xylenol, ethylphenol, propylphenol, butylphenol, phenylphenol, resorcinol, pyrocatechol, hydroquinone, bisphenol A, phlorog Examples include polyhydric phenols such as lucinol and pyrogallol. Specific examples of aldehydes include formaldehyde, acetaldehyde, benzaldehyde, terephthalaldehyde, and the like. Specific examples of 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-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, and the like. 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.

When a hydrogenation reaction product of a phenolic resin is used, the product can be produced by any known method. For example, it can be achieved by dissolving a phenol resin in an organic solvent and introducing hydrogen in the presence of a homogeneous or heterogeneous hydrogenation catalyst. These alkali-soluble 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 amount of the polymer 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.

(Photosensitizer) The photosensitizer used in the present invention is not particularly limited as long as it is a quinonediazidesulfonic acid ester of the compound represented by the general formula (I). For example, 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 -5-sulfonic acid esters and other quinonediazidesulfonic acid esters. The following compounds (1) to (3) are specific examples of the phenol compound represented by the general formula (I), which serves as a mother nucleus of the photosensitive agent used in the present invention.

[0016]

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[0017]

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[0018]

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The photosensitive agent used in the present invention can be synthesized by an esterification reaction between a phenol compound represented by the general formula (I) and a quinonediazidesulfonic acid compound. Examples of the quinonediazidesulfonic acid compound include 1,2-benzoquinonediazide-4-sulfonic acid,
1,2-naphthoquinonediazide-4-sulfonic acid,
2-naphthoquinonediazide-5-sulfonic acid, 2,1-
Examples thereof include o-quinonediazidesulfonic acid compounds such as naphthoquinonediazide-4-sulfonic acid and 2,1-naphthoquinonediazide-5-sulfonic acid, and other quinonediazidesulfonic acid derivatives.

The quinonediazidesulfonic acid ester used in the present invention is obtained by converting a quinonediazidesulfonic acid compound into a sulfonyl chloride with chlorosulfonic acid according to a conventional method, and obtaining the resulting quinonediazidosulfonyl chloride;
It is obtained by condensing with the phenol compound represented by the general formula (I). For example, a phenol compound represented by the general formula (I) and 1,2-naphthoquinonediazide-
A predetermined amount of 5-sulfonyl chloride is dissolved in a solvent such as dioxane, acetone or tetrahydrofuran, and reacted by adding a basic catalyst such as triethylamine, pyridine, sodium carbonate, sodium hydrogen carbonate, sodium hydroxide or potassium hydroxide to obtain a solution. Wash the product with water,
It can be prepared by drying.

In the photosensitive agent used in the present invention, the esterification ratio (average esterification ratio) of the quinonediazidesulfonic acid compound to the phenol compound represented by the general formula (I) is not particularly limited. Usually, it is in the range of 20 to 100%, preferably 50 to 95%, more preferably 65 to 90% of the OH group of the phenol compound. If the ratio of esterification is too low, pattern shape and resolution may be deteriorated. If the ratio of esterification is too high, sensitivity may be deteriorated.

The mixing ratio of the photosensitive agent used in the present invention is not particularly limited, but is usually 1 to 100 parts by weight based on 100 parts by weight of the alkali-soluble phenol resin.
Preferably 3 to 50 parts by weight, more preferably 10 to 40 parts by weight
Parts by weight. If the compounding ratio is too small, a sufficient residual film ratio cannot be obtained, leading to deterioration in resolution. Conversely, if the compounding ratio is too large, heat resistance deteriorates, which is not preferable.

The photosensitive agents used in the present invention can be used alone or in combination of two or more. Further, within a range that does not impair the object of the present invention,
Another type of photosensitizer may be used in a mixture with a small amount (generally, 30% by weight or less of the total amount of the photosensitizer). Other types of photosensitive agents to be mixed are not particularly limited,
Any known quinonediazidesulfonic acid ester can be used.

(Other Components) The positive resist composition of the present invention is usually used by dissolving it in a solvent in order to form a resist film by coating it on a substrate. Examples of the solvent include ketones such as acetone, methyl ethyl ketone, cyclohexanone, cyclopentanone and 2-heptanone; alcohols such as n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol and cyclohexanol; ethylene glycol dimethyl ether, ethylene glycol Ethers such as 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,
Esters such as ethyl propionate, methyl butyrate and ethyl butyrate; monooxycarboxylic acid esters such as ethyl 2-oxypropionate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate and ethyl 2-ethoxypropionate; Cellosolve acetate, methyl cellosolve acetate, ethyl cellosolve acetate,
Cellosolve esters such as propyl cellosolve acetate and butyl cellosolve acetate; propylene glycols such as propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and propylene glycol monobutyl ether; diethylene glycol monomethyl ether and diethylene glycol mono ethyl ether, diethylene glycol dimethyl ether, diethylene glycol et Chirueteru, diethylene glycols such as diethylene glycol methyl ethyl ether; halogenated hydrocarbons such as trichlorethylene; toluene, aromatic hydrocarbons such as xylene; dimethylacetamide,
And polar solvents such as dimethylformamide and N-methylacetamide. These solvents can be used alone or in combination of two or more. If necessary, the positive resist composition of the present invention may contain compatible additives such as dyes, surfactants, storage stabilizers, sensitizers, striation inhibitors, and plasticizers. it can.

As a developer for the positive resist composition of the present invention, an aqueous alkali solution is used. Specifically, sodium hydroxide, potassium hydroxide, sodium silicate,
Inorganic amines such as ammonia; primary amines such as ethylamine and propylamine; second amines such as diethylamine and dipropylamine; tertiary amines such as trimethylamine and triethylamine; dimethylmethanolamine and triethanolamine Alcohol amines; tetramethylammonium hydroxide,
Examples include quaternary ammonium salts such as tetraethylammonium hydroxide, trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammonium hydroxide, and trimethylhydroxyethylammonium hydroxide. Further, if necessary, appropriate amounts of a water-soluble organic solvent such as methanol, ethanol, propanol, and ethylene glycol, a surfactant, a storage stabilizer, a resin dissolution inhibitor, and the like can be added to the aqueous alkali solution.

[0026]

The present invention will be described more specifically below with reference to examples and comparative examples. Parts and percentages are by weight unless otherwise specified.

Example 1 A novolak resin obtained by mixing m-cresol and p-cresol at a molar ratio of 55:45, adding formalin thereto, and condensing by an ordinary method using an oxalic acid catalyst. 100 parts and 70% of the OH groups of the compound (1) are 1,2-naphthoquinonediazide-5-
30 parts of quinonediazide sulfonic acid ester, which is a sulfonic acid ester, is dissolved in 350 parts of ethyl lactate and filtered through a polytetrafluoroethylene fluoroethylene filter (PTFE filter) having a pore diameter of 0.1 μm.
A resist solution was prepared.

The resist solution was applied on a silicon wafer by a spin coater, and prebaked on a hot plate at 90 ° C. for 90 seconds to form a resist film having a film thickness of 1.17 μm. The silicon wafer on which this resist film was formed was exposed using an i-line stepper NSR-1755i7A (manufactured by Nikon Corporation, NA = 0.50) and a reticle for test. Next, the wafer was baked (PEB) for 60 seconds on a hot plate at 110 ° C., and then 2.38.
23% aqueous solution of tetramethylammonium hydroxide
Developing by paddle method at 1 ° C. for 1 minute to form a positive pattern. When the wafer on which this pattern was formed was taken out and observed with an electron microscope, a 0.38 μm line & space was resolved. When the film thickness of the pattern was measured with a film thickness meter Alpha Step 200 (manufactured by Tenko), it was 1.16 μm.

Example 2 Example 2 was repeated except that a compound in which 70% of the OH groups of the compound (2) was 1,2-naphthoquinonediazide-5-sulfonic acid ester was used as the quinonediazidesulfonic acid ester. A resist solution was prepared with the same composition and formulation as in Example 1. Using this resist solution, a positive pattern was formed under the same conditions as in Example 1 and observed with an electron microscope.
8 μm lines and spaces were resolved. The film thickness of the pattern was 1.16 μm.

Example 3 Example 3 was repeated except that a compound in which 80% of the OH groups of the compound (3) was 1,2-naphthoquinonediazide-5-sulfonic acid ester was used as the quinonediazidesulfonic acid ester. A resist solution was prepared with the same composition and formulation as in Example 1. Using this resist solution, a positive pattern was formed under the same conditions as in Example 1 and observed with an electron microscope.
8 μm lines and spaces were resolved. The film thickness of the pattern was 1.16 μm.

Comparative Example 1 As a quinonediazidesulfonic acid ester, the OH of a compound represented by the following chemical formula was used.
80% of the groups are 1,2-naphthoquinonediazide-5-sulfonic esters. A resist solution was prepared with the same composition and formulation as in Example 1 except that a certain compound was used.
Using this resist solution, a positive pattern was formed under the same conditions as in Example 1, and observation with an electron microscope revealed that a line and space of 0.45 μm had been resolved. The pattern thickness was 1.10 μm.

[0032]

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Comparative Example 2 As a quinonediazidesulfonic acid ester, the OH of a compound represented by the following chemical formula was used.
A resist solution was prepared according to the same composition and formulation as in Example 1, except that a compound in which 85% of the groups were 1,2-naphthoquinonediazide-5-sulfonic acid ester was used. Using this resist solution, a positive pattern was formed under the same conditions as in Example 1, and observation with an electron microscope revealed that a line and space of 0.45 μm had been resolved. The film thickness of the pattern was 1.15 μm.

[0034]

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Comparative Example 3 As a quinonediazide sulfonic acid ester, the OH of a compound represented by the following chemical formula was used.
A resist solution was prepared in the same composition and formulation as in Example 1, except that a compound in which 90% of the groups were 1,2-naphthoquinonediazide-5-sulfonic acid ester was used. Using this resist solution, a positive pattern was formed under the same conditions as in Example 1, and observation with an electron microscope revealed that a line and space of 0.45 μm had been resolved. The film thickness of the pattern was 1.15 μm.

[0036]

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[Comparative Example 4] As a quinonediazidesulfonic acid ester, OH of a compound represented by the following chemical formula was used.
A resist solution was prepared in the same composition and formulation as in Example 1 except that a compound in which 70% of the groups were 1,2-naphthoquinonediazide-5-sulfonic acid ester was used. Using this resist solution, a positive pattern was formed under the same conditions as in Example 1, and observation with an electron microscope revealed that a line and space of 0.45 μm had been resolved. The film thickness of the pattern was 1.15 μm.

[0038]

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[0039]

According to the present invention, it is possible to provide a positive resist composition excellent in various properties such as sensitivity, residual film ratio, resolution and heat resistance. The positive resist of the present invention is
In particular, it has excellent sensitivity and residual film ratio, and is suitable for fine processing of 1 μm or less.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Nakamura 1-2-1 Yoko, Kawasaki-ku, Kawasaki-shi, Kanagawa Japan Zeon Corporation (56) References JP-A-2-285351 (JP, A) JP-A-3-228057 (JP, A) JP-A-5-216220 (JP, A) JP-A-6-167805 (JP, A) JP-A-6-202321 (JP, A) International publication 90/1726 (WO, A1) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03F ^7/ 00-7/42

Claims (1)

(57) [Claims] 1. A positive resist composition containing an alkali-soluble phenol resin and a photosensitizer, characterized in that the photosensitizer contains a quinonediazidesulfonic acid ester of a phenol compound represented by the following general formula [I]. Positive resist composition. Embedded image (In the formula, R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ^{3 to} R ⁶ are an alkyl group having 1 to 4 carbon atoms.)