JP3462317B2 - Negative photoresist composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has high resolution and high sensitivity suitable for fine processing in the electronic industry such as manufacturing of semiconductor devices and processing of transparent conductive film for liquid crystal display, and has a good profile. The present invention relates to a negative photoresist composition capable of forming a resist pattern having a shape.

[0002]

2. Description of the Related Art With the increase in the density and the degree of integration of semiconductor devices, the photoresist used in the manufacture thereof is required to have a high resolution. 0.5 μm for the lithography technology that is currently the mainstream in the semiconductor device manufacturing field
The following microfabrication is required.

As a negative photoresist composition applicable to the above-described fine processing, phenol novolac,
For a combination of an alkali-soluble resin such as cresol novolac and an acid crosslinkable compound such as alkoxymethylated melamine, a photoresist composition containing a photoacid generator that generates an acid upon irradiation with light has been proposed, for example, JP-A-2-146044 and JP-A-7-13
4412, JP-A-7-140653, etc. propose to use a 2-aryl or arylethenyl-4,6-bis (trihalomethyl) -s-triazine compound as a photoacid generator. There is. However, when these conventional halomethyltriazine compounds are used, not only the resolution and sensitivity are still insufficient, but there are drawbacks such as etching failure due to the triazine compound sublimated during post-baking after development. , Was not satisfactory in practice.

Therefore, an object of the present invention is to provide a high-sensitivity negative photoresist composition capable of forming a good resist pattern with high resolution.

[0005]

As a result of intensive studies, the present inventors have found that a specific carbazolyltriazine compound has extremely high sensitivity as a photoacid generator, and an alkali-soluble resin, an acid crosslinkable compound and It has been found that a negative photoresist composition containing the carbazolyltriazine compound can achieve the above object.

The present invention has been made based on the above findings, and includes an alkali-soluble resin, an acid-crosslinking compound, and a carba represented by the following general formula (I) (Chemical formula 1). Provided is a negative photoresist composition containing a zolyltriazine compound.

[0007]

[Chemical 2]

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The negative photoresist composition of the present invention will be described in detail below.

Examples of the alkali-soluble resin used in the present invention include novolac resins, acrylic resins, styrene-acrylic acid copolymers, hydroxystyrene polymers and copolymers, isopropenylphenol polymers and copolymers. Among them, novolac resin is particularly preferable.

The above novolak resin is obtained by condensing an aromatic hydroxy compound and an aldehyde in the presence of an acidic catalyst.

Examples of the aromatic hydroxy compound include phenol, o-cresol, m-cresol, p-cresol, 2,5-xylenol, 3,5-xylenol, 3,4-xylenol, 2,3-xylenol, ethyl. Phenol, isopropylphenol, tert-butylphenol, trimethylphenol, methoxyphenol, ethoxyphenol, chlorophenol, phenylphenol, naphthol, biphenol, bisphenol A, resorcinol and the like can be mentioned. These aromatic hydroxy compounds can be used alone or in combination of two or more. It can be mixed and used.

Examples of the aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, etc. These aldehydes can be used alone or in combination of two or more.

As the acidic catalyst, hydrochloric acid, sulfuric acid, formic acid, acetic acid, oxalic acid or the like can be used.

The molecular weight of the above novolak resin is not particularly limited, and usually the weight average molecular weight is 10,000 to 30,000.
Those having a weight average molecular weight of 2,000 to 20,000, which are obtained by cutting a low molecular weight substance, are particularly preferable. If the weight average molecular weight is less than 1,000, the film loss of the unexposed area after development is large, and if it exceeds 30,000, the developing rate may be low, which is not preferable.

The acid-crosslinkable compound used in the present invention is used for insolubilizing an alkali-soluble resin such as a novolak resin by a crosslinking or polymerization reaction in the presence of an acid catalyst. A typical example is a compound having a methylol group or a substituted methylol group as a formaldehyde precursor.

Specific examples of the compound having a methylol group or a substituted methylol group include various aminoplasts, that is, urea-formaldehyde resin, melamine-formaldehyde resin, benzoguanamine-formaldehyde resin, glycoluril-formaldehyde resin, and these. Examples thereof include alkyl ether compounds (alkoxymethyl compounds), and these may be monomers or oligomers having a low degree of polymerization.

The above-mentioned aminoplasts are condensed by reacting melamine, urea, benzoguanamine and the like with formaldehyde in the presence of an acidic catalyst, and then, if necessary,
It can be easily produced by etherification with a lower alcohol such as methanol, ethanol, propanol or butanol.

Among the above aminoplasts, melamine-formaldehyde resin and its alkyl ether compound and alkoxymethylated melamine resin are preferable.
These are commercially available for applications such as vehicles for paints,
In the present invention, commercially available products can be used as they are. Examples of the commercially available products include Cymel (registered trademark) series manufactured by American Cyanamid, Nikalac (registered trademark) series manufactured by Sanwa Chemical Co., Ltd., and the like.

In the composition of the present invention, the alkali-soluble resin and the acid-crosslinkable compound are present in a concentration necessary for film formation, and the mixing ratio thereof (alkali-soluble resin:
The acid crosslinkable compound) is preferably in a weight ratio of 60:40 to 99: 1. When the amount of the alkali-soluble resin is less than 60% by weight of the total amount of both, the releasability after substrate processing is lowered, and the acid-crosslinkable compound is less than 1% by weight of the total amount of both, and high sensitivity cannot be obtained. This is not preferable because the film loss may increase and the shape may deteriorate.

The carbazolyltriazine compound represented by the general formula (I) used in the present invention is used as a photoacid generator. In the general formula (I), the alkyl group having 1 to 4 carbon atoms represented by R ₁ and R ₂ is a group such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and tert-butyl. Examples of the halogen atom represented by R ₁ , R ₂ and X include a chlorine atom, a bromine atom, a fluorine atom and an iodine atom, and the number of carbon atoms represented by R ₃ is 1 to 12
As the alkylene group of, for example, methylene, ethylene, 1,2-propylene, 1,3-propylene, 1,4
Groups such as butylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decamethylene, undecamethylene, dodecamethylene, and the like. The alkylene group having 2 to 4 carbon atoms represented by R ₄ is ethylene. , 1,2-propylene, 1,3-propylene, 1,2-butylene, 1,3-butylene, 1,4
Examples of the alkyl group having 1 to 18 carbon atoms represented by R ₅ include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, amyl and isoamyl groups. Hexyl, heptyl, octyl, isooctyl, 2-ethylhexyl,
Examples thereof include groups such as nonyl, decyl, undecyl, dodecyl, tetradecyl, hexadecyl and octadecyl. Examples of the alkenyl group having 2 to 12 carbon atoms include vinyl, allyl, butenyl, hexenyl, octenyl, decenyl,
Examples thereof include groups such as dodecenyl and octadecenyl, examples of the cycloalkyl group include groups such as cyclopentyl, cyclohexyl, methylcyclohexyl, cyclooctyl, cyclododecyl, and examples of the aralkyl group include benzyl, methylbenzyl, phenylethyl, 2- Examples thereof include groups such as phenylisopropyl, and examples of the alkyl group having 1 to 18 carbon atoms or the aryl group which may be substituted with a halogen atom include phenyl and naphthyl which may be substituted with the above alkyl group or a halogen atom. The base is given.

Among the carbazolyltriazine compounds represented by the general formula (I), the compound in which X is a chlorine atom has particularly high sensitivity, and Z is --CO--.
The compound of O- is preferable because it has excellent storage stability when it is used as a negative photoresist composition.

Therefore, among the carbazolyltriazine compounds represented by the general formula (I), the following compounds are particularly preferable.

Compound 1: 2- (Nn-butyl-3'-
Carbazolyl) -4,6-bis (trichloromethyl)-
s-triazine

Compound 2: 2- (Nn-octyl-3 ')
-Carbazolyl) -4,6-bis (trichloromethyl)-
s-triazine

Compound 3: 2- (N- (2 "-methoxyethyl) -3'-carbazolyl) -4,6-bis (trichloromethyl) -s-triazine

Compound 4: 2- (N- (2 "-phenoxyethyl) -3'-carbazolyl) -4,6-bis (trichloromethyl) -s-triazine

Compound 5: 2- (N- (2 "-p-tert-butylphenoxyethyl) -3'-carbazolyl) -4,
6-bis (trichloromethyl) -s-triazine

Compound 6: 2- (N- (2 "-p-chlorophenoxyethyl) -3'-carbazolyl) -4,6-
Bis (trichloromethyl) -s-triazine

Compound 7: 2- (N-ethoxycarbonylmethyl-3'-carbazolyl) -4,6-bis (trichloromethyl) -s-triazine

Compound 8: 2- (N-butoxycarbonylmethyl-3'-carbazolyl) -4,6-bis (trichloromethyl) -s-triazine

Compound 9: 2- (N-isoamyloxycarbonylmethyl-3'-carbazolyl) -4,6-bis (trichloromethyl) -s-triazine

Compound 10: 2- (N- (2 "-methoxy-1" -methylethoxy) carbonylmethyl-3'-carbazolyl) -4,6-bis (trichloromethyl) -s
-Triazine

Compound 11: 2- (N-benzyloxycarbonylmethyl-3'-carbazolyl) -4,6-bis (trichloromethyl) -s-triazine

Compound 12: 2- (N-cyclohexyloxycarbonylmethyl-3'-carbazolyl) -4,6-
Bis (trichloromethyl) -s-triazine

Compound 13: 2- (N- (2 "-n-octoxycarbonylethyl) -3'-carbazolyl)-
4,6-bis (trichloromethyl) -s-triazine

Compound 14: 2- (N- (2 "-acetoxyethyl) -3'-carbazolyl) -4,6-bis (trichloromethyl) -s-triazine

Compound 15: 2- (N- (2 "-benzoyloxyethyl) -3'-carbazolyl) -4,6-bis (trichloromethyl) -s-triazine

The content of the carbazolyltriazine compound is preferably 0.1 to 20% by weight, more preferably 0.5 to 15% by weight, based on the total amount of the alkali-soluble resin and the acid-crosslinking compound. %. When the content is 0.
If it is less than 1% by weight, high sensitivity cannot be obtained, and the film loss of the image is increased to deteriorate the shape, and if it exceeds 20% by weight, the development residue is increased or the sectional shape of the image is an inverted trapezoid. It is not preferable because it may occur.

The above-mentioned carbazolyltriazine compound is obtained by a known method for producing a halomethyltriazine compound, for example, by reacting a 3-cyano-N-substituted carbazole compound with trihaloacetonitrile in the presence of aluminum halide. It can be easily manufactured.

Next, specific synthesis examples of the carbazolyltriazine compound will be shown, but the present invention is not limited by the following synthesis examples.

[Synthesis Example] (2- (Nn-butyl-3 ')
-Carbazolyl) -4,6-bis (trichloromethyl)
Synthesis of -s-triazine (Compound 1; Compound of Structural Formula of [Chemical Formula 3] below)

[0042]

[Chemical 3]

Step a (Production of 3-formyl-N-n-butylcarbazole) 16.7 parts by weight of carbazole, 22.1 parts by weight of n-butyl iodide, 30 parts by weight of toluene, 80 parts by weight of 50% aqueous sodium hydroxide solution. And 0.6 part by weight of benzyltetraethylammonium chloride were taken, stirred at 90 ° C. for 2 hours, and then cooled to room temperature. Then, the organic layer is taken, washed until the washing liquid becomes neutral, and then dried,
A toluene solution of -n-butylcarbazole was obtained. 61.3 parts by weight of phosphorus oxychloride, 29.2 parts by weight of dimethylformamide and 81.6 parts by weight of toluene were added thereto, and the mixture was stirred under reflux for 4 hours. A 10% aqueous sodium hydroxide solution was added dropwise until the aqueous layer was alkaline, the organic layer was collected, and the solvent was distilled off under reduced pressure to give 3-formyl-Nn.
-Butylcarbazole was obtained.

Step b (Production of 3-cyano-Nn-butylcarbazole) 25.1 parts by weight of 3-formyl-Nn-butylcarbazole obtained in the above step a and 8.3 parts by weight of hydroxylamine hydrochloride. Then, 10.7 parts by weight of sodium acetate and 15 parts by weight of acetic acid were taken and stirred under reflux for 12 hours. After distilling off acetic acid, the residue was dissolved in chloroform and washed until the washing liquid became neutral, and then chloroform was distilled off. The obtained residue was recrystallized from ethanol to give 3-cyano-Nn-butylcarbazole.

Step c (manufacture of target product) 3-Cyano-N-n-butylcalcium obtained in the above step b
Bazole 24.8 parts by weight, trichloroacetonitrile 7
2.2 parts by weight and 2.7 parts by weight of aluminum bromide
No absorption of hydrogen chloride gas was observed at 20 to 30 ° C
It took 3 hours to stir while blowing until the temperature became low.
After that, the contents will solidify gradually, so it will take 15 hours at room temperature.
I left it. Add 300 parts by weight of chloroform, wash with water and dry.
After drying, the solvent was distilled off and the resulting yellow solid was washed with isopropanol.
Recrystallized from toluene / toluene (200/35) mixed solvent,
Light yellow powder with melting point 220-221 ° C, λmax 385 nm
45.6 parts by weight of powdered product was obtained. The product is infrared
As a result of line absorption analysis, 1540, 1390 and 770c
m ^-1Since absorption based on the triazine ring is observed in
It was confirmed that it was the target product.

The above-mentioned carbazolyltriazine compound used as the photo-acid generator alone can give a composition having sufficiently high sensitivity, but when the absorption wavelength does not sufficiently overlap with the exposure wavelength, etc. Other photoacid generators and / or photosensitizers can also be used in combination.

In the present invention, conventionally known compounds can be used as other photoacid generators and photosensitizers which can be used in combination with the carbazolyltriazine compound used as the photoacid generator. , Benzophenone, tetramethyldiaminobenzophenone, tetraethyldiaminobenzophenone, 1-hydroxy-1-benzoylcyclohexane, benzyl, benzyldimethylketal, 1-benzyl-1-dimethylamino-1-
(4′-morpholinobenzoyl) propane, 2-morpholyl-2- (4′-methylmercapto) benzoylpropane, thioxanthone, 1-chloro-4-propoxythioxanthone, isopropylthioxanthone, diethylthioxanthone, ethylanthraquinone, 4-benzoyl-4. '-Methyldiphenyl sulfide, benzoin butyl ether, 2-hydroxy-2-benzoylpropane, 2-hydroxy-2- (4'-isopropyl) benzoylpropane, 4-butylbenzoyltrichloromethane, 4-phenoxybenzoyldichloromethane, methyl benzoylformate, 1,7-bis (9'-acridinyl)
Heptane, 9-n-butyl-3,6-bis (2'-morpholinoisobutyroyl) carbazole, 2-methyl-
4,6-bis (trichloromethyl) -s-triazine,
2-phenyl-4,6-bis (trichloromethyl) -s
-Triazine, 2-naphthyl-4,6-bis (trichloromethyl) -s-triazine and the like.

The composition of the present invention may further contain an additional resin for improving the performance of the resist film, if necessary.
Conventional additives such as plasticizers, stabilizers, surfactants, colorants and dyes can be added.

Further, the composition of the present invention is usually a solvent capable of dissolving or dispersing each of the above-mentioned components, if necessary, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methylocerosolve, ethyl cellosolve, metho Tirocellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, dioxane, ethyl acetate, ethyl lactate, chloroform, methylene chloride, hexane, heptane, octane, cyclohexane, benzene, toluene , Xylene,
It is used as a solution-like composition to which methanol, ethanol and isopropanol are added.

The solution-like composition is prepared by a well-known suitable coating method using a spinner, coater or the like, which is used for manufacturing a liquid crystal display device plate, a glass / ITO coated substrate, a glass / silicon nitride coated substrate, a precision integrated circuit device. Coated on a silicon / silicon dioxide coated substrate used for the production of aluminum, a roughened aluminum substrate used for lithographic printing, etc., and then g-line, h-line, i-line, excimer laser, X-ray, etc. are passed through a predetermined mask. Exposure, then 80-20
After heat treatment at a temperature of about 0 ° C., development is performed, and then,
A good resist pattern can be obtained by further performing heat treatment at a temperature of about 80 to 200 ° C., if necessary.

As the developing solution used for developing the composition of the present invention, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate,
Inorganic alkalis such as aqueous ammonia, ethylamine, propylamine, diethylamine, dibutylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, pyrrole, piperidine and other organic amines, tetramethylammonium hydroxide, tetraethylammonium hydroxide An aqueous solution of an alkali such as a quaternary ammonium salt may be used, and the developer may be used after appropriately adding alcohols and a surfactant.

[0052]

The present invention will be described in more detail with reference to specific examples, but the present invention is not limited to the following examples.

Examples 1 to 15 and Comparative Examples 1 and 2 90 parts by weight of cresol novolac resin (meta / para = 6/4, weight average molecular weight 4500), alkoxymethylated melamine resin (Nikalac Mw30, manufactured by Sanwa Chemical Co., Ltd.)
10 parts by weight and 1 part by weight of a photo-acid generator (see Table 1 below) were dissolved in 299 parts by weight of propylene glycol monomethyl ether acetate, and this solution was filtered through a 0.2 μm microfilter to obtain a photoresist. A composition was prepared.

This photoresist composition was applied on a clean silicon wafer using a spinner and dried on a hot plate at 90 ° C. for 60 seconds to obtain a resist film having a thickness of 1.5 μm. This was exposed through a mask with a reduction projection exposure device (g-line, numerical aperture 0.30) while changing the exposure amount stepwise, and then exposed on a hot plate at 110 ° C. for 120
After heating for 2 seconds, it was developed with a 2.4% aqueous solution of tetramethylammonium hydroxide for 60 seconds, washed with water for 30 seconds and dried.

The sensitivity was evaluated by the exposure dose at which the residual film yield after development of the irradiated portion was 50%. Further, the fine pattern of the resist on the wafer obtained with this exposure amount was observed with a scanning electron microscope, and the resolution was evaluated by the minimum dimension at which the resist pattern was separated to the substrate surface. The results are shown in [Table 1] below.

[0056]

[Table 1]

From the results of the above [Table 1], the compositions of the present invention (Examples 1 to 15) were found to be trichloromethyl-
Compositions using s-triazine compound (Comparative Examples 1 and 2)
It is clear that the sensitivity and the resolution are high as compared with.

Examples 16-30 and Comparative Examples 3-5 97 parts by weight of cresol novolac resin (meta / para = 7/3, weight average molecular weight 6000), alkoxymethylated melamine resin (Nikalac Mw30, manufactured by Sanwa Chemical Co., Ltd.)
3 parts by weight and 3 parts by weight of a photo-acid generator (see Table 2 below) were dissolved in 397 parts by weight of ethyl lactate, and 0.2 μm was further added.
A photoresist composition was prepared by filtering this solution with a microfilter of.

This photoresist composition was applied on a surface-treated silicon wafer left in an atmosphere of hexamethyldisilazane for 7 minutes by using a spinner and dried on a hot plate at 90 ° C. for 90 seconds to give a film thickness. 1.0 μm
A resist film of was obtained. This is a reduction projection exposure device (g line,
The exposure is changed stepwise through a mask with a numerical aperture of 0.30) and then exposed on a hot plate at 110 ° C. for 90 minutes.
After heating for 2 seconds, it was developed with a 2.4% aqueous solution of tetramethylammonium hydroxide for 60 seconds, washed with water for 30 seconds and dried. The wafer is then 90 ° at 160 ° C.
The resist pattern was created by baking for 2 seconds.

The shape of the obtained resist pattern was observed, and a profile which was vertically raised from the silicon wafer surface was determined to have a good profile, and a reverse trapezoidal shape was determined to have a bad profile.

Further, when 500 wafers were processed by the same operation and baked at 160 ° C. for 90 seconds,
Whether or not crystals of the triazine compound were observed on the inner wall of the processing chamber was observed, and the sublimation property was evaluated according to the following criteria. Crystals are not observed even after baking of 1: 500 sheets. 2: 400-499 crystals are observed after baking. Crystals are observed after baking from 3: 300 to 399 sheets. Crystals are observed after baking 4: 200 to 299 sheets. 5: 199 sheets Crystals are observed before baking.

[0062]

[Table 2]

From the results of the above [Table 2], the compositions of the present invention (Examples 16 to 30) were prepared using the conventionally known trichloromethyl-s-triazine compound (Comparative Examples 3 to 3).
Since a resist pattern having a good profile shape equal to or more than that of 5) is provided, and there is no sublimation of crystals during post-baking, continuous operation is possible for a long time.

[0064]

INDUSTRIAL APPLICABILITY The negative photoresist composition of the present invention has a high resolution and sensitivity, can provide a resist pattern having a good profile, and has very little crystal sublimation during post-baking. . Therefore, the negative photoresist composition of the present invention is suitable for a micro-photoresist for liquid crystal display plate processing or semiconductor processing and a photosensitive printing plate for flat plates.

Continuation of the front page (56) Reference JP-A-6-308729 (JP, A) JP-A-2-4787 (JP, A) JP-A-5-165213 (JP, A) JP-A-53-133428 (JP , A) JP-A-2-63054 (JP, A) JP-A-7-140653 (JP, A) JP-A-62-58241 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) G03F 7/00-7/42

Claims (7)

(57) [Claims] 1. A negative photoresist composition containing an alkali-soluble resin, an acid crosslinkable compound, and a carbazolyltriazine compound represented by the following general formula (I). [Chemical 1] 2. The negative photoresist composition according to claim 1, wherein the alkali-soluble resin is a novolac resin. 3. The negative photoresist composition according to claim 1, wherein the acid-crosslinkable compound is a melamine-formaldehyde resin or an alkyl ether compound thereof. 4. The mixing ratio of the alkali-soluble resin and the acid-crosslinkable compound is 60:40 to 99: 1 by weight.
The negative photoresist composition according to claim 1, wherein 5. The negative photoresist composition according to claim 1, which contains the carbazolyltriazine compound in which X is a chlorine atom. 6. The negative photoresist composition according to claim 1, which contains the carbazolyltriazine compound in which Z is —CO—O—. 7. The content of the carbazolyltriazine compound is 0.1 to 20% by weight based on the total amount of the alkali-soluble resin and the acid-crosslinkable compound.
The negative photoresist composition described.