JPH09146278A - Photosensitive resin composition and production of resist image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a compsn. contg. a nearly harmless solvent satisfying sufficiently high power to dissolve a resist material, a proper rate of evaporation, proper surface tension and viscosity by using a specified acetic ester. SOLUTION: This compsn. is a chemical amplification type photosensitive resin compsn. contg. a resin soluble in an aq. alkali soln., a compd. which generates an acid when irradiated with active chemical rays, a medium having such reactivity as to vary solubility to the aq. alkali soln. by a reaction with the acid as a catalyst and a solvent which is 5-9C acetic ester represented by the formula (where R is 3-7C alkyl, alkenyl, alkynyl or phenyl), e.g. n-propyl acetate, isopropyl acetate, isopropenyl acetate, n-butyl acetate or isobutyl acetate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a photosensitive resin composition and a resist image used for microfabrication of a semiconductor device or the like, and particularly to a pattern of radiation such as ultraviolet rays, far ultraviolet rays, X-rays and electron beams. -Like photosensitive resin composition that generates an acid in the pattern latent image forming part by a circular irradiation and changes the solubility of the irradiated part and the non-irradiated part in an alkali developing solution by a reaction using this acid as a catalyst to reveal a pattern. The present invention relates to a product and a method for producing a resist image using the same.

[0002]

2. Description of the Related Art In recent years, integrated circuits have become finer with higher integration, and 64M or 256M DRAM and the like have been required to form a pattern of sub-half micron or less. Therefore, a resist material having excellent resolution can be obtained. Is requested. Conventionally, a reduction projection exposure apparatus has been used for producing an integrated circuit. At present, a pattern having an exposure wavelength or less can be resolved by devising a photomask or the like. However, a resolving power sufficient to support 64M or 256M DRAM has not been obtained.

On the other hand, exposure using X-rays or electron beams can be expected to achieve finer pattern processing than exposure using light. The minimum size of the pattern depends on the beam diameter, and high resolution can be obtained. However, no matter how fine the exposure method is capable of processing, the throughput of wafer processing becomes a problem from the viewpoint of mass production of LSI. As a method for improving throughput, it is important not only to improve the apparatus but also to increase the sensitivity of the resist used.

As a resist material for achieving high sensitivity, for example, a composition containing a highly reactive medium in the presence of an acid catalyst and an acid precursor which generates an acid upon irradiation with actinic radiation is disclosed in US Pat. 3,779,778, JP-A-59-4
The compositions described in JP-A-5439 and JP-A-2-25850 are known. These known examples include compounds or polymers containing an acetal group as a highly reactive medium,
Compounds or polymers containing t-butyl groups are disclosed. Since these media contain an acid-decomposable group, they are converted into a compound or a polymer that changes the solubility in a developer by using an acid generated by irradiation with actinic radiation as a catalyst.

These resist materials are usually dissolved in an appropriate solvent and applied on a substrate such as a wafer or glass by a spin coating method or the like. In order to form a good resist film on these substrates, sufficient solubility of the solvent in the resist material, proper evaporation rate of the solvent, proper surface tension of the solvent, proper viscosity of the solvent, etc. are required. From these facts, there are not so many kinds of solvents that can be selected as the solvent for the resist material.

Conventionally, as such a solvent, ethylene glycol ethers, for example, monomethyl ether or monoethyl ether of ethylene glycol,
These acetates, ethylene glycol methyl ether acetate or ethylene glycol ethyl ether acetate, have been commonly used.

However, in recent years, ethylene glycol ethers have been pointed out as chronic toxicities such as teratogenicity and reproductive toxicity as adverse effects on the human body, and the semiconductor industry is safe without such chronic toxicity. Substitution to solvent is required.

[0008]

SUMMARY OF THE INVENTION Claim 1 or Claim 2
The present invention in (1) is a photosensitive resin using a solvent that is low in toxicity and satisfies sufficient solubility of a solvent in a resist material, an appropriate evaporation rate of the solvent, an appropriate surface tension of the solvent, an appropriate viscosity of the solvent, and the like. It is to provide a composition. The invention according to claim 2 provides a method of manufacturing a resist image capable of forming a resist pattern with high resolution.

[0009]

Means for Solving the Problems The present invention comprises: (a) an alkali aqueous solution-soluble resin; (b) a compound which produces an acid upon irradiation with active actinic radiation; and (c) an acid-catalyzed reaction to change the solubility in an alkali aqueous solution. A chemically amplified photosensitive resin composition comprising a reactive medium and a solvent (d), wherein the solvent (d) has a carbon number of 5 to 9 (general formula (1)).

Embedded image (In the general formula (1), R represents an alkyl group having 3 to 7 carbon atoms, an alkenyl group, an alkynyl group, or a phenyl group), which is an acetic acid ester.
The present invention also relates to (b) the above-mentioned photosensitive resin composition, wherein the compound which produces an acid upon irradiation with active actinic radiation is an ester of an aromatic compound having a phenolic hydroxyl group and an alkylsulfonic acid or an aromatic sulfonic acid. . The present invention
Further, the present invention relates to a method for producing a resist image, which comprises irradiating a coating film of the photosensitive resin composition with active actinic rays and then developing the resist image.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Examples of the acetic acid ester having 5 to 9 carbon atoms in the present invention include n-propyl acetate, isopropyl acetate, isopropenyl acetate, n-butyl acetate, isobutyl acetate, t-butyl acetate and acetic acid. Examples include n-pentyl, isopentyl acetate, s-pentyl acetate, t-pentyl acetate, n-hexyl acetate, 2-hexenyl acetate, 5-hexenyl acetate, n-heptyl acetate, 6-heptenyl acetate and phenyl acetate. The acetic acid ester having 5 to 9 carbon atoms in the present invention may be used alone or in combination of two or more.

The amount of acetic acid ester having 5 to 9 carbon atoms used in the present invention is preferably 50 to 95% by weight, more preferably 70 to 95% by weight, based on the photosensitive resin composition.
It is preferred that If there are too few acetates,
Sufficient solubility of the solvent in the resist material tends to be insufficient, and when the amount of the acetic acid ester is too large, a sufficient film thickness cannot be obtained when forming a resist film.

The alkali aqueous solution-soluble resin used in the present invention is not particularly limited as long as it is a resin that is soluble in an alkali aqueous solution, but phenols having one or more phenolic hydroxyl groups are polycondensed with aldehydes. Novolac resins are preferred. For example, phenol, o-cresol, m-cresol, p-cresol, 2,3-
Phenols such as xylenol, 2,4-xylenol, 2,5-xylenol, 3,4-xylenol, 3,5-xylenol, 2,3,5-trimethylphenol.
Examples include phenols having one phenolic hydroxyl group, phenols having two phenolic hydroxyl groups such as resorcinol and catechol, and phenols having three phenolic hydroxyl groups such as phloroglucin, pyrogallol and hydroxyhydroquinone. These phenols are
Each can be used alone or in combination of two or more. Aldehydes include, for example, formaldehyde, paraformaldehyde and the like. The amount of the aldehyde used is preferably in the range of 0.5 to 1.5 mol per 1 mol of the phenol. As the catalyst for polycondensation, an acid catalyst capable of increasing the molecular weight is preferable. Examples of the acid catalyst include inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid, and organic acids such as formic acid, oxalic acid, and acetic acid. The acid catalyst is used in an amount of 1 mol of phenols.
The range of 1 × 10 ^-5 to 1 × 10 ^-1 mol is preferable. The reaction temperature and reaction time of the polycondensation can be appropriately adjusted according to the reactivity of the synthetic raw material, but the reaction temperature is usually 70 to
The temperature is 130 ° C., and the reaction time is 1 to 12 hours. Examples of the polycondensation method include a method in which phenols, aldehydes and a catalyst are charged at a time, and a method in which phenols and aldehydes are added in the presence of a catalyst as the reaction proceeds. After completion of polycondensation, in order to remove unreacted raw materials, condensed water, catalyst, etc. existing in the reaction system,
The temperature in the reaction system is raised to 150 to 200 ° C. under reduced pressure, for example, 20 to 50 mmHg, and then the resin is recovered.

Examples of compounds which generate an acid upon irradiation with active actinic radiation used in the present invention include onium salts, halogen-containing compounds, quinonediazide compounds and sulfonic acid ester compounds. As the onium salt, for example,
Iodonium salts, sulfonium salts, phosphonium salts, ammonium salts, diazonium salts and the like can be mentioned, and preferably diaryl iodonium salts, triarylsulfonium salts, trialkylsulfonium salts (wherein the alkyl group has 1 to 4 carbon atoms), The counter anion of the onium salt includes, for example, tetrafluoroboric acid, hexafluoroantimonic acid, trifluoromethanesulfonic acid, trifluoroacetic acid and toluenesulfonic acid. Examples of the halogen-containing compound include a haloalkyl group-containing hydrocarbon compound and a haloalkyl group-containing heterocyclic compound, and preferably include trichloromethyltriazine and bromoacetylbenzene. Examples of the quinonediazide compound include a diazobenzoquinone compound and a diazonaphthoquinone compound.

Examples of the sulfonic acid ester compound include esters of an aromatic compound having a phenolic hydroxyl group with an alkylsulfonic acid or an aromatic sulfonic acid. For example, as an aromatic compound having a phenolic hydroxyl group. Is phenol, resorcinol, pyrogallo
Sulfonic acid, methanesulfonic acid, ethanesulfonic acid, propylsulfonic acid, butylsulfonic acid, and aromatic sulfonic acid such as phenylsulfonic acid and naphthylsulfonic acid. Acids and the like. An ester of an aromatic compound having a phenolic hydroxyl group with an alkylsulfonic acid can be synthesized by a usual esterification reaction. For example, an aromatic compound having a phenolic hydroxyl group can be reacted with an alkyl sulfonic acid or a chloride of an aromatic sulfonic acid under an alkaline catalyst. The synthetic product thus obtained can be purified by a recrystallization method or a reprecipitation method using an appropriate solvent.

From the viewpoint of providing sufficient sensitivity to active actinic radiation, the amount of the compound which produces an acid upon irradiation with active actinic radiation is set to 5 with respect to 100 parts by weight of the aqueous solution of alkali solution.
It is preferably from 30 to 30 parts by weight, and further from 5 to 15 parts by weight.
It is preferably in parts by weight. If the amount of the compound that generates an acid by active actinic radiation is too large, the solubility in a solvent is reduced. If the amount is too small, sufficient sensitivity cannot be obtained.

As a medium having a reactivity that changes the solubility in an alkaline aqueous solution by an acid-catalyzed reaction, there are those that have an increased solubility and a reduced solubility in an alkaline aqueous solution due to the acid-catalyzed reaction.

As a reaction mechanism for increasing the solubility in an alkaline aqueous solution, there is a mechanism in which the solubility in the alkaline aqueous solution is promoted by hydrolysis of the above reactive medium by an acid-catalyzed reaction.

As an example of the above-mentioned reactive medium that is hydrolyzed by an acid-catalyzed reaction, novolac resin, acrylic resin,
Dissociates hydrogen atoms such as phenolic hydroxyl group and carboxyl group of styrene-acrylic acid copolymer, hydroxystyrene polymer, alkaline aqueous solution soluble resin such as polyvinylphenol (same as above) in the presence of acid. And a compound substituted with a group capable of being substituted.
Specific examples of the group capable of dissociating in the presence of an acid include a methoxymethyl group, a methoxyethoxymethyl group, a tetrahydropyranyl group, a tetrahydrofuranyl group, a benzyloxymethyl group, a 1-methoxyethyl group, and 1-ethoxy. Examples thereof include ethyl group, methoxybenzyl group, t-butyl group, methoxycarbonyl group, ethoxycarbonyl group, t-butoxycarbonyl group, trimethylsilyl group, triethylsilyl group and phenyldimethylsilyl group. Of these, a tetrahydropyranyl group, a tetrahydrofuranyl group, a t-butoxycarbonyl group, a 1-ethoxyethyl group, a triethylsilyl group and the like are preferable. The substitution ratio of the group capable of dissociating in the presence of an acid to hydrogen of the phenolic hydroxyl group or the carboxyl group is 15 to 10
It is preferably 0%, and more preferably 30 to 100%.

As a reaction mechanism in which the solubility in an alkaline aqueous solution is lowered, there is a mechanism in which the solubility in an alkaline aqueous solution is inhibited by polymerization and condensation reaction in the above-mentioned reactive medium by an acid catalyst reaction. As a mechanism for realizing this mechanism, for example, a crosslinking agent which is polymerized or condensed by an acid-catalyzed reaction itself or polycondensed with the above-described alkali aqueous solution-soluble resin is exemplified. The crosslinking agent is not particularly limited as long as it is a compound having a substituent capable of undergoing a crosslinking reaction. Specific examples of the crosslinkable substituent include a glycidyl ether group, a glycidyl ester group, a glycidylamino group, a methoxymethyl group, an ethoxymethyl group, a benzyloxymethyl group, a dimethylaminomethyl group, and a benzoyloxymethyl group. Examples of compounds having these substituents include bisphenol A epoxy compounds, bisphenol F epoxy compounds, nopolak epoxy compounds, methylol group-containing phenol compounds, alkyl ether group-containing melamine compounds, and carboxymethyl group-containing melamine compounds. Is mentioned. In this system, a cross-linking reaction of the reactive medium itself occurs due to polymerization and condensation reaction by an acid-catalyzed reaction, and the solubility in an aqueous alkaline solution is reduced.

Further, the amount of the medium having the reactivity that changes the solubility in the alkaline aqueous solution by the acid-catalyzed reaction has a sufficient residual resist film ratio and a high γ value, that is, a high resolution The amount is preferably 5 to 30 parts by weight, and more preferably 5 to 20 parts by weight, based on 100 parts by weight of the soluble resin. If the addition amount of the medium having the reactivity to change the solubility in the alkaline aqueous solution by the acid catalyzed reaction is too large, the irradiation part may increase the solubility in the alkaline aqueous solution by the acid catalyzed reaction in the system in which the solubility is increased with respect to the developing solution. The dissolution rate tends to decrease, and the resolution tends to decrease in a system in which the irradiated part has a reduced solubility in an aqueous alkali solution due to an acid catalyzed reaction. Further, if the amount of the medium having the reactivity to change the solubility in the aqueous alkali solution by the acid catalyzed reaction is too small, the irradiated portion may increase the solubility in the aqueous alkali solution by the acid catalyzed reaction. Film loss is increased, and sensitivity tends to decrease in a system in which the irradiated portion has reduced solubility in an aqueous alkali solution due to an acid catalyzed reaction.

The photosensitive resin composition of the present invention has a coating property,
For example, in order to prevent striation (unevenness in film thickness) and improve developability, a surfactant can be added. As the surfactant, for example, polyoxyethylene uralyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, commercially available products such as Megafax F171, F173 (Dainippon Ink ) Product name), Florard FC430, FC43
1 (trade name of Sumitomo 3M Ltd.), organosiloxane polymer KP341 (trade name of Shin-Etsu Chemical Co., Ltd.) and the like. Further, the photosensitive resin composition of the present invention may optionally contain a storage stabilizer, a dissolution inhibitor, and the like.

With the photosensitive resin composition of the present invention, a resist image is produced by forming a resist film on a substrate such as a wafer or glass and irradiating with active actinic rays and developing. Irradiation with active actinic rays and conditions for development are not limited, and, for example, far ultraviolet rays such as excimer lasers, X-rays such as synchrotron radiation, and charged particle rays such as electron beams are used.

The developer of the photosensitive resin composition of the present invention includes, for example, inorganic alkalis such as sodium hydroxide, primary amines such as ethylamine, secondary amines such as diethylamine, and secondary amines such as triethylamine. Tertiary amines,
Alkaline aqueous solutions in which alcohol amines such as dimethylethanolamine, quaternary ammonium salts such as tetramethylammonium hydroxide and choline, or cyclic amines such as piperidine are dissolved are used.

[0024]

The present invention will be described below with reference to examples. Synthesis Example 1 m-cresol 328.1 g and p-cresol 4 were placed in a separable flask equipped with a stirrer, a condenser and a thermometer.
00.9 g, 361.2 g of 37% by weight formalin and 2.2 g of oxalic acid were charged, the separable flask was immersed in an oil bath, and polycondensation was performed for 3 hours while stirring at an internal temperature of 97 ° C. Thereafter, the internal temperature was raised to 180 ° C., and simultaneously the pressure in the reaction vessel was reduced to 10 to 20 mmHg to remove unreacted phenols, formaldehyde, water and oxalic acid.
Next, the molten resin was poured into a metal vat to collect the resin. Hereinafter, this resin is referred to as resin A.

Synthesis Example 2 Poly (p-vinylphenol) (trade name: Linker-M, Maruzen Petrochemical Co., Ltd.) was placed in a separable flask equipped with a stirrer.
20 ml) and 300 ml of ethyl acetate.
℃) to dissolve. Then, in the flask,
105 g of 4-dihydro-2H-pyran, 12N hydrochloric acid 0.1 g.
5 ml was added, and the mixture was stirred at room temperature for 1 hour.
Left for days. Next, 160 ml of a 2.38% by weight aqueous solution of tetramethylammonium hydroxide was added to the reaction solution, and the mixture was stirred well, and the organic layer was taken out. The obtained organic layer solution was washed three times with 300 ml of distilled water, and then the organic layer was dried and concentrated by an evaporator. Concentrated solution 5
Reprecipitation was performed using 500 ml of petroleum ether for 0 ml. After repeating the reprecipitation operation twice, the product was dried in a vacuum dryer (3 mmHg, 40 ° C.) for 8 hours, and poly (p-vinylphenol) in which hydroxyl hydrogen was substituted by 95% tetrahydropyranyl group. 22 g were obtained.

Synthesis Example 3 A separable flask equipped with a stirrer, a condenser and a thermometer was charged with 18.9 g of pyrogallol and 200 ml of pyridine, and the mixture was stirred and dissolved at room temperature (25 ° C.). Next, 69 g of ethanesulfonyl chloride was added to the flask at 50 ° C.
Add dropwise little by little so as not to exceed. After dropping ethanesulfonyl chloride, the mixture is stirred at room temperature for 3 hours. After the reaction,
Pour the reaction solution into 1000 ml of water and precipitate the product. After thoroughly washing the precipitate with water and repeating the recrystallization operation twice with a mixed solvent of acetone and methanol, the product was dried in a vacuum dryer (3 mmHg, 40 ° C) for 8 hours, and pyrogallol triethanesulfone was added. 10 g of acid ester was obtained.

Synthetic Example 4 In Synthetic Example 3, 69 g of ethanesulfonyl chloride
Was synthesized in the same manner as in Synthesis Example 3 except that 95 g of phenylsulfonyl chloride was used instead of As a result, pyrogallol triphenylsulfonate 12
g was obtained.

Example 1 90 g of Resin A obtained in Synthesis Example 1, 10 g of poly (p-vinylphenol) obtained by reacting the hydroxyl group obtained in Synthesis Example 2 with a tetrahydropyranyl group, and pyrogallol obtained in Synthesis Example 3 1g of ethanesulfonic acid ester of isopentyl acetate 40
After being dissolved in 0 g, it was filtered through a membrane filter having a pore size of 0.2 μm to prepare a positive resist. The obtained resist solution is applied on a silicon wafer and the temperature is maintained at 80 ° C for 10 minutes.
A heat treatment was performed for a minute to obtain a resist film having a film thickness of 0.5 μm.
An electron beam drawing apparatus with an accelerating voltage of 30 kV was used to draw a hole pattern on the resist at a dose of 3.0 μC / cm ² and then heat treated at 100 ° C. for 10 minutes to remove the latent image portion of the resist. It promoted a reaction that increased the solubility in aqueous alkaline solutions. After this heat treatment, the latent image formed resist film was developed for 120 seconds using a 2.38 wt% aqueous solution of tetramethylammonium hydroxide. The cross-sectional shape of the 0.5 μm hole pattern was observed with an electron microscope. As a result, the resist shape is rectangular and 0.5μ, which is exactly as designed.
It was confirmed that the hole pattern of m was resolved.

Example 2 In Example 1, except that 2 g of the phenylsulfonic acid ester of pyrogallol obtained in Synthesis Example 4 was used instead of 1 g of the ethanesulfonic acid ester of pyrogallol obtained in Synthesis Example 3. A positive resist was prepared in the same manner as in Example 1. A resist pattern was formed in the same manner as in Example 1 except that the exposure was performed at a dose of 4.0 μC / cm ² , and the pattern was 0.5 μm.
The cross-sectional shape of the hole pattern was evaluated. As a result, it was confirmed that the resist pattern was rectangular and a hole pattern of 0.5 μm as designed was resolved.

Example 3 A positive resist was prepared in the same manner as in Example 1 except that butyl acetate was used in place of isopentyl acetate, and a resist pattern was formed to a thickness of 0.5 μm.
The cross-sectional shape of the hole pattern was evaluated. As a result, it was confirmed that the resist pattern was rectangular and a hole pattern of 0.5 μm as designed was resolved.

Example 4 100 g of Resin A obtained in Synthesis Example 1, 15 g of amino resin (Cymel 303, manufactured by Mitsui Cyanamid Co., Ltd.) and 2 g of ethanesulfonic acid ester of pyrogallol obtained in Synthesis Example 3
Was dissolved in 400 g of isopentyl acetate, and then the pore size of 0.
A negative resist was prepared by filtering with a 2 μm membrane filter. The obtained resist solution was applied onto a silicon wafer and heat-treated at 100 ° C. for 10 minutes to obtain a resist film having a thickness of 1.0 μm. An electron beam drawing apparatus with an accelerating voltage of 30 kV was used to draw a line & space pattern on the resist at a dose of 7.0 μC / cm ² and then 100
Heat treatment was performed at 10 ° C. for 10 minutes to accelerate the reaction of increasing the solubility of the latent image portion of the resist in the aqueous alkaline solution. After this heat treatment, 2.
The resist film on which a latent image was formed was developed for 120 seconds using a 38 wt% aqueous solution. The cross-sectional shape of the 0.5 μm line & space pattern was observed with an electron microscope. As a result, the resist shape is rectangular and 0.5 μm line &
It was confirmed that the space pattern was resolved.

[0032]

EFFECTS OF THE INVENTION The photosensitive resin composition according to claim 1 or 2 is less harmful and has sufficient solubility in the photosensitive resin composition, an appropriate evaporation rate, an appropriate surface tension, an appropriate viscosity, etc. It is possible to obtain a photosensitive resin composition using a solvent satisfying the above conditions. By the method of manufacturing a resist image according to the third aspect, a resist pattern with good resolution can be formed.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shigeru Nishio, 4-13-1, Higashi-cho, Hitachi-shi, Ibaraki Hitachi Chemical Co., Ltd. Yamazaki factory (72) Mitsuaki Hashimoto, 4-chome, Higashi-cho, Hitachi, Ibaraki No. 1 Hitachi Chemical Co., Ltd. Yamazaki Plant (72) Inventor Toshio Sakamizu 1-280, Higashi Koigakubo, Kokubunji, Tokyo Metropolitan Research Center, Hitachi, Ltd. (72) Hiroshi Shiraishi 1-280 Higashi Koigaku, Kokubunji, Tokyo Address: Central Research Laboratory, Hitachi, Ltd.

Claims (3)

[Claims] (1) an aqueous alkali-soluble resin,
(B) a compound which produces an acid upon irradiation with active actinic radiation, (c)
What is claimed is: 1. A chemically amplified photosensitive resin composition comprising a medium (d) which has a reactivity to change the solubility in an alkaline aqueous solution by an acid-catalyzed reaction, and (d) the solvent has 5 carbon atoms.
9 to 9 [general formula (1)] (In the general formula (1), R represents an alkyl group having 3 to 7 carbon atoms, an alkenyl group, an alkynyl group, or a phenyl group), which is an acetic acid ester. 2. The photosensitive resin according to claim 1, wherein the compound (b) which produces an acid upon irradiation with active actinic radiation is an ester of an aromatic compound having a phenolic hydroxyl group and an alkylsulfonic acid or an aromatic sulfonic acid. Composition. 3. A method for producing a resist image, which comprises irradiating a coating film of the photosensitive resin composition according to claim 1 or 2 with active actinic radiation and then developing the resist image.