JP3279059B2 - Photoresist 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 photoresist composition suitable for lithography using far ultraviolet rays (including an excimer laser or the like).

[0002]

2. Description of the Related Art In recent years, with the increasing integration of integrated circuits, submicron pattern formation has been required. In particular, excimer laser lithography is used for 64M and 256M DR.
It's gaining attention because it makes AM production possible. And with the change to such a laser light source,
The resist is required to have the following new properties in addition to the conventional properties such as heat resistance, remaining film ratio, and profile.

B) High sensitivity to the light source. B) High resolution.

[0004] In view of such circumstances, a so-called chemically amplified resist utilizing an acid catalyst and a chemical amplification effect has been proposed. The mechanism of action of this resist is to change the solubility of an exposed part and an unexposed part in an alkali developing solution by a reaction using an acid generated from a photoacid generator by light irradiation as a catalyst. The chemically amplified resist gives a positive or negative resist pattern by such a mechanism.

As a resin for a chemically amplified resist, polyvinyl phenol has been used in many cases. However, since polyvinylphenol has too high a solubility in an alkali developing solution, there has been a problem that a resist using the same has insufficient sensitivity and resolution.

[0006]

SUMMARY OF THE INVENTION The inventors of the present invention have repeatedly conducted research on polyvinylphenol-based resins used for chemically amplified resists, and as a result, they have excellent performance by using a specific resin. The present inventors have found that a photoresist composition can be obtained, and have reached the present invention. An object of the present invention therefore, there is heat resistance, residual film ratio, coating properties, while maintaining various performances profile such as to provide a negative full photoresists compositions sensitivity and excellent chemical amplification type in resolution .

[0007]

That is, the present invention provides a photoresist composition containing the following components.

(A) an alkali-soluble resin containing a vinylphenol-based resin selected from the group consisting of partially alkyletherified polyvinylphenol and partially alkyletherified hydrogenated polyvinylphenol, (B) Sulfonate of N-hydroxyimide compound
A negative photoresist composition comprising a photoacid generator containing at least one of the following, and (C) a crosslinking agent. (However, as a crosslinking agent, the following general formula Wherein Q ₁ is an alkyl group having 1 to 10 carbon atoms or aralkyl
Represents Le group, Q ₂ is a hydrogen atom, a hydroxyl group, a C1-5
An alkoxy group, an alkyl group having 1 to 10 carbon atoms or OCH
₂ OQ ₁ (however, Q ₁ is the same as above). ]
Excluding compounds. )

In the present invention, as the alkali-soluble resin,
A partially alkyletherified polyvinylphenol or a partially alkyletherified hydrogenated polyvinylphenol is used. Of course, both can be used together. These resins are polyvinylphenols or partially hydrogenated products thereof, and have a great feature in that a part of the hydroxyl groups is alkyl etherified.

The partially alkyletherified polyvinyl phenol is poly (p-vinylphenol), and the proportion of the alkyl etherified portion of the hydroxyl groups (alkyl etherification ratio) is 10 to 10.
It is preferably 35 mol%, and more preferably, the alkyl etherification ratio is 15 to 22 mol%.
As the partially alkylated etherified hydrogenated polyvinyl phenol, those having an alkyl etherification rate of 5 to 30 mol% are preferred. In particular, the alkyl etherification rate is more preferably 8 to 20 mol%. When the partially alkyletherified polyvinylphenol and the hydrogenated polyvinylphenol are used in combination, the mixing ratio of both is appropriately set.

Further, together with one or both of these,
Other alkali-soluble resins can also be used in combination. Examples of the alkali-soluble resin that can be used in combination include vinyl phenol resin, isopropenyl phenol resin, a copolymer of vinyl phenol and styrene (the proportion of vinyl phenol in the copolymer is preferably 50 mol% or more), isopropenyl. copolymers of phenol with styrene (proportion of isopropenylphenol in the copolymer at least 50 mol% is preferred), such as hydrogen added polyvinyl phenol. These other alkali-soluble resins may be appropriately mixed with partially alkyletherified polyvinylphenol and / or partially alkyletherified hydrogenated polyvinylphenol within a range not to impair the effects of the present invention. Used in proportions.

The alkyl ether in the partially alkyletherified polyvinylphenol and / or the partially alkyletherified hydrogenated polyvinylphenol may be straight-chain or branched, but has 1 to 4 carbon atoms.
Are preferred. Particularly preferred are methyl ether and ethyl ether.

[0013] Partially alkyl etherified polyvinyl phenols include, for example, polyvinyl phenol and alkyl halides, described by GN Vyas et al., Org.
Vol. IV, 836 (1963). The partially alkyletherified hydrogenated polyvinyl phenol can be produced, for example, by a method of reacting a hydrogenated polyvinyl phenol with an alkyl halide according to the description of GN Vyas et al. Hydrogenated polyvinyl phenol can be produced by hydrogenating polyvinyl phenol according to a conventional method.

The alkali-soluble resin preferably has a polystyrene equivalent weight average molecular weight determined by gel permeation chromatography (GPC) in the range of 1,000 to 10,000.
More preferably, it is in the range of 1,500 to 8,000.

[0015] As the acid generator is needed use a sulfonic acid ester of N- hydroxy imide compounds. Specific examples of such sulfonic acid esters include compounds represented by the following general formula (I).

[0016]

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In the formula, R ¹ represents an optionally substituted arylene, alkylene or alkenylene group, and R ² represents an optionally substituted alkyl or aryl group.

In the general formula (I), the arylene group represented by R ¹ may be monocyclic or bicyclic, and specific examples of the arylene group include phenylene and naphthylene. Suitable substituents on the arylene group include a halogen atom, a nitro group and an acetylamino group. Similarly, the alkylene group may be linear or branched, and preferably has 1 to 6 carbon atoms. Particularly preferred alkylene groups are ethylene, propylene and the like. Suitable substituents for the alkylene group include
Examples include a halogen atom, a lower alkoxy group, and a monocyclic aryl group. Similarly, the alkenylene group may have 2 to 6 carbon atoms, and preferably includes vinylene. Suitable substituents of the alkenylene group include a monocyclic aryl group.

In the general formula (I), the alkyl group represented by R ² may be linear, branched or cyclic, but is preferably a linear or branched C ¹ to C ⁸ alkyl group.
One. Suitable substituents for the alkyl group include a lower alkoxy group. Similarly, the aryl group may be monocyclic or bicyclic, but preferably monocyclic.

Among the sulfonic acid esters represented by the general formula (I), preferred are compounds represented by the following general formula (II).

[0021]

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In the formula, R ¹ has the same meaning as described above, and R ^{2 ′}
Represents an optionally substituted alkyl or aryl group, but when R ^{2 ′} is a substituted alkyl or aryl group, the substituent is not fluorine.

The sulfonic acid ester represented by the general formula (I) is described, for example, in GF Jaubert, Ber. Dtsch. Chem.,
28 , 360 (1895), DE Ames et al., J. Chem. Soc., 35
18 (1955), MA Stolberg et al., J. Amer. Chem. So
c., 79 , 2615 (1957), etc., by the following general formula (III)

[0024]

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(Wherein R ¹ has the same meaning as described above)
To produce a cyclic N-hydroxyimide compound represented by
This is described, for example, in L. Bauer et al., J. Org. Chem., 24 , 129.
3 (1959), by reacting with a sulfonic acid chloride corresponding to R ² —SO ₂ Cl (where R ² has the same meaning as described above) under basic conditions,
Can be manufactured.

The sulfonic acid esters of the N-hydroxyimide compounds corresponding to the general formulas (I) and (II) can be used alone or in combination of two or more. Specific examples of the sulfonic acid ester of the N-hydroxyimide compound suitable for use in the present invention include the following compounds.

[0027]

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As the crosslinking agent used in the photoresist composition of the present invention, for example, a compound having a methylol group or a methylol ether group described in Japanese Patent Application No. 4-15009 (= JP-A-5-210239) can be used. No. Such a crosslinking agent having a methylol group or a methylol ether group can be used alone or in combination of two or more. Suitable crosslinking agents include, for example, the compounds shown below.

[0029]

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The preferred composition ratio of the negative photoresist composition containing a crosslinking agent is 50 to 95% by weight of an alkali-soluble resin, 1 to 20% by weight of a photoacid generator, and 1 to 30% by weight of a crosslinking agent. It is . At the Ne gas type full photoresists composition, if necessary, a sensitizer may be incorporated dyes, various additives which are conventional in the art, such as adhesion improving agent.

The photoresist solution is usually prepared using the above-mentioned negative type.
Each solid content of the full photoresists composition, so that the total concentration of 10 to 50% by weight, is prepared by mixing in a solvent. As the solvent used here, for example, ethyl cellosolve acetate, methyl cellosolve acetate,
Ethyl cellosolve, methyl cellosolve, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol dimethyl ether, ethyl lactate, butyl acetate, ethyl pyruvate, 2-
Heptanone, cyclohexanone, methyl isobutyl ketone, xylene and the like. These solvents are used alone or in combination of two or more.

[0032]

EFFECTS OF THE INVENTION The photoresist composition of the present invention is not only excellent in various properties such as heat resistance, residual film ratio, coatability and profile, but also exposed using a deep ultraviolet (including excimer laser) light source. The region has high sensitivity and high resolution. Therefore, in lithography using the above light source, the resolution and contrast can be significantly improved, and a fine photoresist pattern with high precision can be formed. In particular, when the alkali-soluble resin contains a partially alkyletherified hydrogenated polyvinylphenol, there is also an effect of further reducing minute development residues (scum).

[0033]

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the examples, unless otherwise specified, parts are by weight.

Reference Example 1 10.0 g of polyvinylphenol (Marcalinker M manufactured by Maruzen Petrochemical; weight average molecular weight 4,150) was dissolved in acetone, and 12.0 g of potassium carbonate and 3.3 g of ethyl iodide were dissolved.
8 g was added and the mixture was heated under reflux for 6 hours. The reaction mixture was poured into a mixture of 600 ml of water and 350 ml of ethyl acetate, acidified by adding hydrochloric acid, shaken and extracted. After the organic layer was washed with water until the washing liquid became neutral, the solvent was distilled off under reduced pressure. The residue was dissolved in 25 ml of methanol and poured into 1.3 liter of water. The precipitate was filtered and dried to give polyvinylphenol having 18.8% of hydroxyl groups ethyletherified.

REFERENCE EXAMPLES 2-4 Except that the amount of ethyl iodide used was changed to 3.84 g, 3.90 g and 2.96 g, respectively, the ethyl etherification ratio was 20.3% in the same manner as in Reference Example 1. , 21.8% and 16.7% of partially ethyl etherified polyvinyl phenol were obtained.

Example 1 13.5 parts of partially ethyl etherified polyvinylphenol having an ethyl etherification ratio of 18.8% obtained in Reference Example 1, 1.0 part of hexamethylolmelamine hexamethyl ether as a crosslinking agent, and a photoacid generator 1.0 part of methanesulfonic acid ester of N-hydroxysuccinimide was dissolved in 48 parts of diethylene glycol dimethyl ether.
This solution was filtered through a Teflon filter having a pore size of 0.1 μm to prepare a resist solution.

This resist solution was applied to a silicon wafer cleaned by a conventional method to a thickness of 0.7 μm using a spin coater. Next, the silicon wafer was pre-baked on a hot plate at 100 ° C. for 1 minute. A KrF excimer laser stepper having an exposure wavelength of 248 nm (NSR-1755 EX8A, manufactured by Nikon Corporation, NA = 0.4) is passed through a chrome mask having a pattern on the coating film after prebaking.
Exposure was performed using 5). After the exposure, the wafer was heated on a hot plate at 100 ° C. for 1 minute to perform a cross-linking reaction of the exposed portion. This was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide to obtain a negative pattern. As a result of observing the formed pattern with an electron microscope, a fine pattern of 0.25 μm was resolved with a good profile at an exposure of 42 mJ / cm ² .
No scum was observed on the wafer from which the resist layer had been removed in the non-exposed areas.

Example 2 A negative pattern was obtained in the same manner as in Example 1 except that the partially etherified polyvinylphenol having an ethyl etherification ratio of 20.3% obtained in Reference Example 2 was used as the alkali-soluble resin. . Observation of the formed pattern with an electron microscope revealed that a 0.25 μm fine pattern could be resolved at an exposure dose of 25 mJ / cm ² .

Example 3 A negative pattern was obtained in the same manner as in Example 1, except that the partially etherified polyvinyl phenol having an ethyl etherification ratio of 21.8% obtained in Reference Example 3 was used as the alkali-soluble resin. . Observation of the formed pattern with an electron microscope revealed that a 0.25 μm fine pattern could be resolved at an exposure dose of 20 mJ / cm ² .

Example 4 A negative pattern was obtained in the same manner as in Example 1, except that the partially ethyl etherified polyvinylphenol having an ethyl etherification ratio of 16.7% obtained in Reference Example 4 was used as the alkali-soluble resin. . Observation of the formed pattern with an electron microscope revealed that a 0.25 μm fine pattern could be resolved at an exposure dose of 29 mJ / cm ² .

Example 5 As an alkali-soluble resin, 8.1 parts of a partially ethyl etherified polyvinylphenol having an ethyl etherification ratio of 20.3% obtained in Reference Example 2 and a molar ratio of vinylphenol to styrene of 70:30 were used. Copolymer (Marukalinker CST-70 manufactured by Maruzen Petrochemical Co .; weight average molecular weight 1,720) 5.4
A negative pattern was obtained in the same manner as in Example 1, except for using the mixture of parts. Observation of the formed pattern with an electron microscope revealed that a 0.25 μm fine pattern could be resolved at an exposure dose of 27 mJ / cm ² .

Comparative Example 1 As an alkali-soluble resin, polyvinyl phenol 13.
A resist solution was prepared in the same manner as in Example 1, except that 5 parts were used. This resist solution was applied to a silicon wafer cleaned by a conventional method to a thickness of 0.7 μm using a spin coater. Next, the silicon wafer was pre-baked in an oven at 100 ° C. for 1 minute. The coating film after prebaking was exposed through a chromium mask having a pattern using the same KrF excimer laser stepper as used in Example 1. After the exposure, the wafer was heated on a hot plate at 105 ° C. for 1 minute to cause a cross-linking reaction of the exposed portion. This was developed with a 2.0% by weight aqueous solution of tetramethylammonium hydroxide to obtain a negative pattern. Observation of the formed pattern with an electron microscope revealed that only a 0.35 μm pattern could be resolved at an exposure dose of 50 mJ / cm ² .

Reference Example 5 Hydrogenated polyvinyl phenol (Marukalinker PHM-C manufactured by Maruzen Petrochemical Co., Ltd .; weight average molecular weight 5,400) 10.0
g was dissolved in acetone, 12.0 g of potassium carbonate and 1.95 g of ethyl iodide were added, and the mixture was heated under reflux for 6 hours. After filtering the reaction mixture, the filtrate was poured into 2,000 ml of an aqueous acetic acid solution of pH 3, and the precipitated resin was collected by filtration and dried. The dried resin was dissolved in acetone so as to have a concentration of 20% by weight, the acetone solution and hexane were mixed at a weight ratio of 2: 1, further stirred at room temperature for 1 hour, and then allowed to stand. Separate the acetone layer and deionize 2,000 m of deionized water
The precipitated resin was collected by filtration and dried to obtain hydrogenated polyvinyl phenol in which 15% of the hydroxyl groups were ethyl etherified.

Reference Example 6 Reference Example 5 except that the amount of ethyl iodide was changed to 1.56 g.
In the same manner as in the above, a partially ethylated hydrogenated polyvinylphenol having an ethyl etherification rate of 12% was obtained.

Example 6 13.5 parts of a partially ethylated hydrogenated polyvinylphenol having an ethyl etherification rate of 15% obtained in Reference Example 5,
1.0 part of hexamethylolmelamine hexamethyl ether as a crosslinking agent and 1.0 part of methanesulfonic acid ester of N-hydroxysuccinimide as a photoacid generator,
It was dissolved in 48 parts of diethylene glycol dimethyl ether. This solution was filtered through a Teflon filter having a pore size of 0.1 μm to prepare a resist solution.

This resist solution was applied to a silicon wafer cleaned by a conventional method to a thickness of 0.7 μm using a spin coater. Next, the silicon wafer was pre-baked on a hot plate at 100 ° C. for 1 minute. The coating film after prebaking was exposed through a chromium mask having a pattern using the same KrF excimer laser stepper as used in Example 1. After the exposure, the wafer was heated on a hot plate at 100 ° C. for 1 minute to perform a cross-linking reaction of the exposed portion. This was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide to obtain a negative pattern. Results The formed pattern was observed by an electron microscope, 0.2 at an exposure amount of 25 mJ / cm ²
A fine pattern of 5 μm was resolved with a good profile, and no scum was observed on the wafer from which the resist layer had been removed in the non-exposed areas.

Example 7 6.75 parts of a partially ethylated hydrogenated polyvinylphenol having an ethyl etherification rate of 15% obtained in Reference Example 5,
6.75 parts of partially ethyl etherified polyvinyl phenol having an ethyl etherification rate of 22%, 1.0 part of hexamethylolmelamine hexamethyl ether as a crosslinking agent, and 0.75 parts of ethanesulfonic acid ester of N-hydroxysuccinimide as a photoacid generator Was dissolved in 60 parts of propylene glycol monomethyl ether acetate. Thereafter, a negative pattern was obtained in the same manner as in Example 6, except that the heating temperature of the exposed wafer was changed to 110 ° C. As a result of observing the formed pattern with an electron microscope, 13 mJ
A fine pattern of 0.25 μm was resolved with a good profile at an exposure dose of / cm ² , and no scum was observed on the wafer from which the resist layer had been removed in the non-exposed areas.

Example 8 10.8 parts of a partially ethylenated hydrogenated polyvinylphenol having an ethyl etherification rate of 12% obtained in Reference Example 6,
2.7 parts of partially ethyl etherified polyvinyl phenol having an ethyl etherification rate of 22%, 1.0 part of hexamethylolmelamine hexamethyl ether as a crosslinking agent, and 0.75 parts of ethanesulfonic acid ester of N-hydroxysuccinimide as a photoacid generator Was dissolved in 60 parts of propylene glycol monomethyl ether acetate. Since then
In the same manner as in Example 7, a negative pattern was obtained. Observation of the formed pattern with an electron microscope revealed that the pattern was 20 mJ / cm ^2.
The fine pattern of 0.25 μm was resolved with a good profile at the exposure amount of, and no scum was observed on the wafer from which the resist layer was removed in the non-exposed area.

The above results for the negative photoresist are summarized in Table 1. In the table, “PV” in the column of resin
“P” is an abbreviation for polyvinylphenol.

[0050]

[Table 1] 樹脂 Resin / ethyl etherification rate Sensitivity Resolution ━━━━━━━━━━━━ ━━━━━━━━━━━━━ Example 1 PVP / 18.8% 42 mJ / cm ² 0.25 μm 〃 2〃 / 20.3% 25 mJ / cm ² 0.25 μm ３3〃 / 21.8% 20 mJ / cm ² 0.25 μm ４ 4 ／ / 16.7% 29 mJ / cm ² 0.25 mm 〃 5 PVP / 20.3% 27 mJ / cm ² 0.25 m phenol-styrene copolymer ──────────────比較 Comparative Example 1 PVP (no protection) 50 mJ / cm ² 0.35μm ────────────────────────実 施 Example 6 hydrogenated PVP / 15% 25 mJ / cm ² 0.25 μm ７ 7 hydrogenated PVP / 15% 13 mJ / cm ² 0.25 μm PVP / 22% 〃 8 hydrogenated PVP / 12% 20 mJ / cm ² 0.25 μm PVP / 22% ━━━━━━━━━━━━━━━━━━━━━━━━━

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takehiro Kusumoto 3-1-198, Kasuganaka, Konohana-ku, Osaka Sumitomo Chemical Co., Ltd. (72) Inventor Hiromi Oka 3-1-1, Kasuganaka, Konohana-ku, Osaka-shi No. 98 Sumitomo Chemical Co., Ltd. (56) References JP-A-4-215662 (JP, A) JP-A-3-107160 (JP, A) JP-A-4-291259 (JP, A) JP-A-3-217458 (JP, A) JP-A-3-206458 (JP, A) JP-A-5-281730 (JP, A) JP-A-5-204157 (JP, A) JP-A-6-83055 (JP, A) A) JP-A-61-166544 (JP, A) JP-A-5-313371 (JP, A) JP-A-5-507563 (JP, A) International publication 92/8166 (WO, A1) (58) Field (Int.Cl. ⁷ , DB name) G03F ^7/ 00-7/42

Claims (4)

(57) [Claims] (A) an alkali-soluble resin containing a vinylphenol-based resin selected from the group consisting of (A) partially alkyletherified polyvinylphenol and partially alkyletherified hydrogenated polyvinylphenol, B) Sulfonate of N-hydroxyimide compound
A negative photoresist composition comprising a photoacid generator containing at least one of the following, and (C) a crosslinking agent. (However, as a crosslinking agent, the following general formula Wherein Q ₁ is an alkyl group having 1 to 10 carbon atoms or aralkyl
Represents Le group, Q ₂ is a hydrogen atom, a hydroxyl group, a C1-5
An alkoxy group, an alkyl group having 1 to 10 carbon atoms or OCH
₂ OQ ₁ (however, Q ₁ is the same as above). ]
Excluding compounds. ) 2. The photoresist according to claim 1, wherein the vinylphenol resin is partially alkyletherified poly (p-vinylphenol), and the alkyletherification ratio is 10 to 35 mol%. Composition. 3. The photoresist composition according to claim 1, wherein the vinylphenol resin is a partially alkyletherified hydrogenated polyvinylphenol having an alkyletherification ratio of 5 to 30 mol%. 4. A sulfonic acid ester of an N-hydroxyimide compound represented by the general formula (I): ## STR1 ## (In the formula, R ¹ represents optionally substituted arylene, alkylene or alkenylene group, R ² represents a optionally substituted alkyl or aryl group) to claim 1 represented by The photoresist composition of any of the preceding claims.