JP3060748B2 - Photosensitive resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an alkali-soluble resin,
The present invention relates to a photosensitive resin composition containing a quinonediazide-based photosensitive compound and a solvent as main components and which is sensitive to radiation such as ultraviolet rays, far ultraviolet rays, electron beams, and X-rays.

[0002]

2. Description of the Related Art Conventionally, a photoresist comprising an alkali-soluble novolak resin and a quinonediazide-based photosensitive compound functioning as an alkali dissolution inhibitor has been known. In such a photoresist, a radiation-irradiated portion decomposes a quinonediazide-based photosensitive compound (hereinafter abbreviated as a photosensitizer) into ketene via a carbene, and reacts with water inside and outside the system to produce indenecarboxylic acid. Then, it is easily dissolved in an alkaline aqueous solution. On the other hand, the non-irradiated portion hardly dissolves in the alkali developer and hardly swells because the photosensitive agent inhibits the solubility of the alkali-soluble novolak resin in the alkali developer (hereinafter, this inhibitory effect is referred to as a masking effect). Maintains high residual film ratio. As a result, a high-resolution resist pattern can be obtained.

In recent years, the density of semiconductor integrated circuits has been increasing,
Manufacturing processes are also increasing in difficulty. In order to respond to such strict requirements, various improvements have been made to photoresist materials, and wide and detailed studies have been made on resins, photosensitizers, developers and additives. With this, the demands on photoresists have become more and more advanced, especially high sensitivity, high resolution, rectangularity of pattern profile,
High dry etching resistance, high heat resistance, and a wide exposure margin are strongly desired. Incidentally, there are two types of expressions of the sensitivity of the photoresist, Eth and E _O , which are defined as follows.

[0004]

[Table 1] Eth: A large area (for example, 2 mm square or more) exposed portion of a photoresist film applied on a substrate was exposed with an alkali developing solution.
The minimum exposure required for complete dissolution to the substrate E _O : a fixed line width on the reticle (for example, 0.
A 6 μm) pattern is developed with an alkaline developer after exposure, so that a target (for example, 0.6 μm) is formed on the wafer.
m) Exposure to be finished to dimensions

[0005] Since Eth is the minimum exposure amount at which the exposed portion of the photoresist dissolves onto the substrate by development, an exposure amount of Eth or more is required to form an image with the photoresist. In an actual semiconductor manufacturing process, naturally, in order to finish a line width to a desired dimension on a mask, E is naturally required.
An exposure amount (E _O ) equal to or larger than th is used. It is said that increasing the ratio of these two exposure amounts, that is, E _O / Eth, increases the exposure margin. To explain this, when the exposure amount is larger than E _O , the line width is smaller than the desired size, and when the exposure amount is smaller than E _O , the line width is larger than the desired size. If the exposure amount is further reduced to a value smaller than Eth, the exposed portion cannot be dissolved on the substrate by development. That is, an image cannot be formed. If E _O / Eth is small, for example, 1, and if the actually used exposure amount is slightly smaller than E _O , the exposure amount immediately becomes Eth or less, making it impossible to form an image and making semiconductor manufacturing difficult. Becomes Conversely, E _O /
If Eth is increased, the range of the exposure amount at which an image can be formed is widened. That is, the exposure margin can be widened.

On the other hand, recently developed high-resolution photoresists aim at improving the resolving power and the exposure margin by increasing the amount of a photosensitizing agent in the resist and increasing the masking effect (for example, see Japanese Patent Application Laid-Open No. H11-163873). 62-136
No. 637, Japanese Journal
f Applied Physics, Vol. 12
8, No. 10, October, 1989, p. 21
10-2113). However, when the amount of the photosensitizer is increased, i which has recently been used in semiconductor lithography is increasing.
Since the absorption of the photosensitive agent is large in the line (wavelength 365 nm) region, the energy difference of the transmitted light between the upper and lower portions of the resist film applied on the wafer becomes large, and the pattern profile becomes trapezoidal and does not become an ideal rectangle. Also, the resolution is not satisfactory. When the amount of the photosensitizer is reduced to solve such a problem, as described above, the sensitivity is improved, but a sufficient masking effect cannot be obtained.
The pattern profile, the resolving power, and the exposure margin are significantly deteriorated. As described above, it is becoming difficult to develop a high-performance resist using the conventional method, and a new idea is required.

[0007]

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a photoresist composition which is superior in pattern profile and developability to conventional products, has high resolution, and is excellent in exposure margin. It is to be.

[0008]

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a specific novolak resin, that is, at least one phenolic compound as an alkali-soluble resin has been obtained. A photosensitive resin composition using a polycondensate of formaldehyde and a specific ketone or aldehyde is a conventional product, that is, a photosensitive resin composition using a polycondensate of a phenolic compound and formaldehyde as an alkali-soluble resin. The present invention was found to have a higher resolving power and an excellent exposure margin as compared with the present invention.

That is, the gist of the present invention is to provide a photosensitive resin composition containing an alkali-soluble resin, a quinonediazide-based photosensitive compound and a solvent as main components, wherein the alkali-soluble resin is at least one kind represented by the following general formula [A]: A polycondensate of (a) formaldehyde and (b) at least one ketone or aldehyde represented by the following general formula [B], and wherein the formaldehyde (a) and the ketone or aldehyde ( The mixing ratio (molar ratio) with b) is 1 / (a) / (b).
99 to 99/1.

[0010]

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[0011]

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[Wherein R ¹ is R ² , OR ³ , COOR ⁴
Or a group represented by CH ₂ COOR ⁵ , wherein R ²
Represents an alkyl group having 1 to 4 carbon atoms, R ³ , R ⁴ and R ⁵ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; n represents an integer of 0 to 3; Or in the case of 3, a plurality of R ¹ may be the same or different, and R ⁶ and R ⁷
Each independently represents a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms, but R ⁶ and R ⁷ are not hydrogen atoms at the same time].

Hereinafter, the present invention will be described in detail. The photosensitive resin composition of the present invention is characterized in that a specific novolak resin is used as the alkali-soluble resin. The phenolic compound used as a component of the novolak resin is represented by the general formula [A], and has the formula [A]
In the above, the alkyl group having 1 to 4 carbon atoms represented by R ² , R ³ , R ⁴ and R ⁵ includes a methyl group, an ethyl group,
Examples thereof include an n-propyl group, an i-propyl group, and an n-butyl group. Further, n represents an integer of 0 to 3, and when n is 2 or 3, a plurality of R ¹ may be the same or different.

The compound represented by the general formula [A] includes, for example, phenol, o-cresol, m-cresol, p-cresol, 2-ethylphenol, 3-ethylphenol, 4-ethylphenol, 2-isopropylphenol , 3-isopropylphenol, 4-isopropylphenol, 2-propylphenol, 3-
Propylphenol, 4-propylphenol, 2-t
-Butylphenol, 3-t-butylphenol, 4-
t-butylphenol, 3,5-dimethylphenol,
2,5-dimethylphenol, 2,3-dimethylphenol, 3,4-dimethylphenol, 2,3-diethylphenol, 2,5-diethylphenol, 3,4-diethylphenol, 3,5-diethylphenol, −
t-butyl-5-methylphenol, 2,3,5-trimethylphenol, 3,4,5-trimethylphenol, resorcinol, 2-methylresorcinol, 4-
Methylresorcinol, 5-methylresorcinol, catechol, 4-t-butylcatechol, pyrogallol,
2-methoxyphenol, 3-methoxyphenol, 4
-Methoxyphenol, 2-methoxyresorcinol,
2,3-dimethoxyphenol, 2,5-dimethoxyphenol, 3,5-dimethoxyphenol, 2-methoxy-5-methylphenol, gallic acid, methyl gallate, ethyl gallate, 3-methoxy-4,5-dihydroxy Methyl benzoate, ethyl 3-methoxy-4,5-dihydroxybenzoate, methyl 4-methoxy-3,5-dihydroxybenzoate, ethyl 4-methoxy-3,5-dihydroxybenzoate, 3,4-dimethoxy-5 -Hydroxybenzoic acid, methyl 3,5-dimethoxy-4-hydroxybenzoate, ethyl 3,5-dimethoxy-4-hydroxybenzoate, 4-hydroxyphenylacetic acid and the like.

In the above formula [A], R¹Is R^Two, OR^Three
Or CH_TwoCOOR^FiveAnd R ^ThreeAnd R^FiveAre each German
It is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
Preferably, specifically, o-cresol, m-cresol
, P-cresol, 3,5-dimethylphenol,
2,5-dimethylphenol, 2,3-dimethylpheno
, 3,4-dimethylphenol, 2,3,5-triol
Methylphenol, 3,4,5-trimethylphenol
, Resorcinol, 2-methylresorcinol, pyro
Galol and 4-hydroxyphenylacetic acid are preferred.
No.

In particular, in the above formula [A], R¹Is R^Twoor
Is OR^ThreeAnd R^TwoIs an alkyl having 1 to 2 carbons
R^ThreeIs preferably a compound having a hydrogen atom.
R^TwoWhen the number of carbon atoms is 3 or more, heat resistance and sensitivity are deteriorated.
Tend to Also, R ^ThreeIs other than a hydrogen atom,
Tends to deteriorate. Of the compound represented by the formula [A]
Among them, m-cresol, p-cresol, 2,5-di
Methylphenol, 2-methylresorcinol, resor
Sinol is particularly preferred, especially (i) m-crezo
, P-cresol, resorcinol and 2-methyl
Resorcinol in a molar ratio of 1 to 7/1 to 7/0 to 2/0
And (ii) m-cresol, p-c
Resole, 2,5-xylenol, resorcinol and
2-methylresorcinol in a molar ratio of 1-7 / 1-7 /
A mixture of 0.1 to 7/0 to 2/0 to 2 is preferred
No. These phenolic compounds can be used
Aldehyde and a ketone or aldehyde represented by the general formula [B]
Alkali-soluble novolak obtained by polycondensation with hydrs
Of the photosensitive resin composition using a black resin, in the above (i)
Is particularly remarkable in heat resistance, and in (ii) above,
The resolving power is remarkably improved.

On the other hand, ketones or aldehydes used as other components of the novolak resin are represented by the above general formula [B]. In the formula [B], the number of carbon atoms represented by R ⁶ and R ⁷ is 1 to 1. As the lower alkyl group of 4, a methyl group,
Examples include an ethyl group, an n-propyl group, an i-propyl group, and an n-butyl group. Among the compounds represented by the general formula [B], examples of the aldehyde include alkyl aldehydes such as acetaldehyde, propionaldehyde, and butyraldehyde. Examples of ketones include acetone and ethyl methyl ketone. Of these compounds, alkyl aldehydes having 2 to 4 carbon atoms in total and acetone are preferred. Particularly, among the compounds represented by the general formula [B], acetaldehyde and propionaldehyde are preferable. Acetaldehyde is particularly preferred because it has practically high sensitivity and can increase the exposure margin. With alkyl aldehydes having a total carbon number of 5 or more, the sensitivity is deteriorated, and it is difficult to obtain a good alkali-soluble resin. These general formulas [B]
May be used alone or as a mixture at an arbitrary ratio.

In the present invention, formaldehyde (a) is further used as a component of the novolak resin. The mixing ratio of the formaldehyde (a) and the ketone or aldehyde (b) represented by the general formula [B] is a molar ratio (a) /
In (b), it is necessary to be 1/99 to 99/1. Preferably 50 / 50-95 / 5, more preferably 70/50.
30-90 / 10, more preferably 75 / 25-8
5/15. If the ketone or aldehyde represented by the general formula (B) is too small, the improvement in resolution and exposure margin is small, while if the ketone or aldehyde represented by the general formula (B) is too large, the deterioration in sensitivity is large. It is difficult to obtain a good alkali-soluble resin.
The mixing ratio is defined as (b) in the definition of the mixing ratio.
Represents the total proportion of the ketone or aldehyde (b) represented by the general formula [B].

As a method for producing the above-mentioned novolak resin, a phenolic compound represented by the above-mentioned general formula [A], a ketone or an aldehyde represented by the above-mentioned general formula [B], depending on the molecular weight of a desired novolak resin. And an appropriate amount of formaldehyde and formaldehyde, and in accordance with a conventional method, for example, a method of mixing, heating and condensation polymerization in the presence of an acid catalyst. As the acid catalyst, for example, an inorganic acid such as hydrochloric acid, nitric acid, and sulfuric acid or an organic acid such as formic acid, oxalic acid, and acetic acid is used.
These may be used alone or as a mixture. In the polycondensation reaction of the present invention, a reaction solvent does not usually need to be used, but a solvent can be used. As this solvent,
For example, alcohols such as methanol, ethanol, and propanol, and ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether are exemplified. The reaction temperature varies depending on the phenolic compound represented by the general formula [A], but is usually from 10 to 200 ° C, preferably from 20 to 150 ° C. After the reaction,
Generally, the internal temperature is raised to 150 to 250 ° C., the unreacted raw material, the acid catalyst and water are distilled off under reduced pressure, and then the melted novolak resin is taken out to obtain a desired novolak resin. Further, those using a reaction solvent can also be obtained by adding the reaction mixture to a solvent such as water after the completion of the reaction to precipitate a novolak resin, collecting the precipitate by filtration, and drying. In the present invention, the above-mentioned novolak resin may be used alone or as a mixture of two or more kinds as the alkali-soluble resin. The weight average molecular weight in terms of polystyrene (hereinafter referred to as MW) of the alkali-soluble resin of the present invention is usually preferably from 2,500 to 30,000. MW is 2
If it is less than 500, the heat resistance of the photosensitive resin composition deteriorates, while if it exceeds 30,000, the sensitivity deteriorates remarkably. A particularly preferred range is 3000 to 2000
0.

The quinonediazide-based photosensitive compound used in the present invention includes 1,2-benzoquinonediazide-4.
-Sulfonic acid, 1,2-naphthoquinonediazide-4-sulfonic acid, 1,2-naphthoquinonediazide-5-sulfonic acid and the like, esterified products of quinonediazidesulfonic acid are preferred, and in particular, 1,2-naphthoquinonediazide-4. −
Sulfonate and 1,2-naphthoquinonediazide-5-sulfonate are preferred.
The esterified product with 4-sulfonic acid has a wavelength of 330 to 42.
The esterified product with 5-sulfonic acid is preferably used when light in the range of 0 nm is used, and is preferable when light in the wavelength range of 330 to 450 nm is used. As the quinonediazide-based photosensitive compound, specifically, the following compounds (a) to (c) or the resin 1,2-benzoquinonediazide-4-
Sulfonate, 1,2-naphthoquinonediazide-
For example, 4-sulfonic acid ester or 1,2-naphthoquinonediazide-5-sulfonic acid ester is used. (A) Polyhydroxy aliphatic compounds such as glycerin and pentaerythritol. (B) Bisphenol A, gallic acid ester, quercetin, morin, polyhydroxybenzophenone, polyhydroxy aromatic compounds such as trisphenols represented by the following general formula [C].

[0021]

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Wherein R ⁸ and R ⁹ each represent hydrogen or an alkyl group having 1 to 4 carbon atoms, and -X- and -Y- each represent an alkylene group having 1 to 4 carbon atoms. (C) A phenolic resin obtained by dehydrating and condensing phenolic aldehydes and / or ketones (hereinafter referred to as ballast resin).

In these quinonediazide sulfonic acid esterified products, the esterification rate of the hydroxy group in the compounds (a) to (c) with the quinonediazidesulfonic acid is usually 30 to 100%, preferably 40 to 10%.
0%. Among the above photosensitive compounds, quinonediazide sulfonic acid esters of polyhydroxy aromatic compounds or ballast resins are preferable, and particularly, polyhydroxybenzophenone, trisphenols represented by the formula (C) or quinonediazide sulfonic acid esters of ballast resins are preferable. It is preferably used.

The polyhydroxybenzophenone includes 2,3,4-trihydroxybenzophenone, 2,2
3,4,4'-tetrahydroxybenzophenone, 2,
2 ', 4,4'-tetrahydroxybenzophenone,
2,2 ', 3,4,4'-pentahydroxybenzophenone, 2,3,3', 4,4 ', 5'-hexahydroxybenzophenone and the like.

As ballast resin, phenol, o
-Cresol, m-cresol, p-cresol, 3-
Ethylphenol, pt-butylphenol, 3,5
-Dimethylphenol, 2,5-dimethylphenol,
Alkylphenols such as 2,3,5-trimethylphenol, arylphenols such as o-hydroxydiphenyl and p-hydroxydiphenyl, resorcinol;
Resorcinols such as 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, 2-ethylresorcinol, 2,5-dimethylresorcinol, catechol, 3-methylcatechol, 4-methylcatechol, 3,5-dimethylcatechol and the like One or more phenolic compounds selected from catechols, pyrogallols, pyrogallols such as 5-methylpyrogallol, and the like, for example, aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, and benzaldehyde, acetone, methyl ethyl ketone, and diethyl ketone And a resin polycondensed with one or more ketones or aldehydes selected from ketones such as acetophenone and benzophenone. The range of the weight average molecular weight of the resin used as the ballast resin is 400 to
2200 is preferred. When the molecular weight of the ballast resin is small, a satisfactory masking effect cannot be obtained, and a good pattern profile cannot be obtained. Conversely, when the molecular weight is large, the sensitivity is significantly deteriorated. The molecular weight of ballast resin is
Particularly preferably, it is in the range of 450 to 1800. or,
When the ballast resin is a resin obtained by dehydration-condensation of m-cresol with formaldehyde and / or acetaldehyde, the ballast resin has excellent effects particularly in resolution and pattern shape.

In addition, as a method for producing such a ballast resin, a phenolic compound and a ketone or aldehyde can be prepared in the presence of an acidic catalyst, for example, 50 to 1 according to a known method.
A method of heating to 00 ° C. for polycondensation is employed. In the present invention, the above-mentioned photosensitive compounds can be used alone or in combination of two or more.

The solvent used in the present invention may be any solvent that can dissolve the quinonediazide-based photosensitive compound and the alkali-soluble resin, and usually has a boiling point of 100 to 180 ° C. from the viewpoint of operability during use. Is preferred. Examples of these solvents include ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate, ether alcohols such as ethyl cellosolve, methyl cellosolve and propylene glycol monomethyl ether, and carboxylic acids such as ethyl acetate and butyl acetate. Acid esters, lactones such as γ-butyrolactone, cyclic ketones such as cyclohexanone, carboxylic acid esters of dibasic acids such as diethyl oxalate and diethyl malonate, glycols such as ethylene glycol diacetate and propylene glycol diacetate. Dicarboxylic esters,
Oxycarboxylic acid esters such as ethyl 2-oxypropionate, ethyl 3-oxypropionate, methyl 3-methoxypropionate, and ethyl 3-methoxypropionate are exemplified. These solvents can be used alone or in combination of two or more.

The concentration of the alkali-soluble resin in the photosensitive resin composition of the present invention is usually from 1 to 30% by weight.
The concentration of the quinonediazide-based photosensitive compound is usually
0.1 to 15% by weight. Further, the ratio of the quinonediazide type photosensitive compound to the alkali-soluble resin is usually 0.1 to 0.5 times by weight. The photosensitive resin composition of the present invention may optionally contain a surfactant such as polyoxyethylene ethers or fluorine-based alkyl esters in order to improve poor coating properties such as striation. . The amount of these additives is usually 2% by weight or less, preferably 1% by weight or less. Further, a dye or the like may be added to reduce the influence of irregularly reflected light from the substrate during image transfer, and a sensitizer or the like may be added to improve sensitivity.

The photosensitive resin composition of the present invention is used through various steps such as application to a substrate, pattern transfer by exposure, development and the like according to a known method. The substrate on which the photoresist composition is applied is a semiconductor substrate such as a silicon wafer. Usually, a spin coater is used to apply the photosensitive resin composition to the substrate, and the thickness of the photosensitive resin composition is usually about 0.3 to 5 μm. Usually, after the application of the photosensitive resin composition, the substrate is heated on a hot plate or the like, and after removing the solvent, the substrate is exposed through a mask, and a desired pattern is printed on the substrate. For exposure, g-line (436 nm),
Light having a wavelength of 330 to 450 nm, such as i-line (365 nm), is preferably used. After exposure, the substrate is optionally 90
After heating at about 120 ° C. for about 60 to 120 seconds, development is performed with an aqueous alkali solution. As the aqueous alkaline solution, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, inorganic alkalis such as aqueous ammonia, ethylamine, primary amines such as n-propylamine,
Secondary amines such as diethylamine and di-n-propylamine; tertiary amines such as triethylamine and trimethylamine; alkalis such as aqueous solutions of quaternary ammonium salts such as tetramethylammonium hydroxide and trimethylhydroxyethylammonium hydroxide; Aqueous solutions are preferably used. Incidentally, an alcohol, a surfactant and the like may be added to the developer as needed.

[0030]

EXAMPLES The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the scope of the present invention. In the following Examples, the molecular weight indicates the weight average molecular weight in terms of polystyrene as a result of analysis by gel permeation chromatography, and the esterification ratio indicates the esterification ratio obtained from the charged molar ratio.

Novolak Resin Synthesis Example 1 A 2-liter separable flask was charged with m-cresol 2
37.91 g, 190.33 g p-cresol, 2,5
-Xylenol 53.75 g, oxalic acid dihydrate 15 g
And 1 ml of 35% hydrochloric acid, 90% under stirring at room temperature
31.8 g of acetaldehyde was added dropwise, followed by stirring at room temperature for 30 minutes. Thereafter, the internal temperature was raised to 95 ° C.
211.4 g of a 10% aqueous solution of formalin was added dropwise, and the reaction was carried out for 5 hours while maintaining the temperature. Then the internal temperature is 180 ℃
The reaction was carried out by evaporating water out of the system while raising the temperature over 1.5 hours. After the water was distilled off, the internal temperature was further raised to 195 ° C., and the unreacted monomer was distilled off under a reduced pressure of 20 torr to obtain a novolak resin (a). Novolak resin (a)
Had a molecular weight of 8,000. The ratio of formaldehyde / acetaldehyde (charged molar ratio) was 8/2.

Novolak Resin Synthesis Example 2 The amount of acetaldehyde and formalin used was 15.6 g of 90% acetaldehyde and a 37% aqueous solution of formalin 23
A novolak resin (b) was obtained in the same manner as in Novolak resin synthesis example 1 except that the amount was changed to 3.0 g. The molecular weight of the novolak resin (b) was 5,000. The ratio of formaldehyde / acetaldehyde (charged molar ratio) was 9/1.

Novolak Resin Synthesis Example 3 Propionaldehyde instead of acetaldehyde
Using 3 g, 214.3 g of 37% formalin aqueous solution
A novolak resin (c) was obtained in the same manner as in Novolak resin synthesis example 1 except that it was used. The molecular weight of the novolak resin (c) was 5000. Incidentally, the formaldehyde / propionaldehyde (the molar ratio charged) was 8/2.

Novolak Resin Synthesis Example 4 m-cresol 23 was placed in a 2-liter separable flask.
7.91 g, 190.33 g p-cresol, 2,5-
Xylenol 53.75 g and oxalic acid dihydrate 15 g
Was added, the internal temperature was raised to 95 ° C. with stirring, 249.3 g of a 37% aqueous formalin solution was added dropwise, and the reaction was carried out for 5 hours while maintaining the temperature. Then the internal temperature was raised to 180 ° C.
Water was distilled out of the system while the temperature was raised over 5 hours to carry out the reaction. After distilling off water, the internal temperature was further raised to 195 ° C.
Under reduced pressure of torr, unreacted monomers were distilled off to obtain novolak resin (d). Its molecular weight was 5000.

Novolak Resin Synthesis Example 5 The amounts of acetaldehyde and formalin used were 46.8 g of acetaldehyde and a 37% aqueous solution of formalin 181.
A novolak resin (e) was obtained in the same manner as in Novolak resin synthesis example 1 except that the amount was changed to 2 g. The molecular weight of the novolak resin (e) was 4000. The ratio of formaldehyde / acetaldehyde (charged molar ratio) was 7/3.

Novolak Resin Synthesis Example 6 Acetaldehyde and formalin were used in an amount of 85.1 g of 90% acetaldehyde and a 37% aqueous solution of formalin 1
A novolak resin (f) was obtained in the same manner as in Novolak resin synthesis example 1 except that the composition was changed to 41.1 g. The molecular weight of the novolak resin (f) was 3,500. The formaldehyde / acetaldehyde (charge molar ratio) was 5/5
Met.

Novolak Resin Synthesis Example 7 Acetaldehyde and formalin were used in an amount of 7.7 g of 90% acetaldehyde and a 37% aqueous solution of formalin 24
A novolak resin (g) was obtained in the same manner as in Novolak resin synthesis example 1, except that 2.23 g was used. The molecular weight of the novolak resin (g) was 5,500. In addition, the formaldehyde / acetaldehyde (feed molar ratio) was 95 /
It was 5.

Ballast Resin Synthesis Example 1 475.2 g of m-cresol, oxalic acid dihydrate 15
g, 1 ml of 35% hydrochloric acid, 90% acetaldehyde 26.
A ballast resin (a) was obtained in the same manner as in Novolak resin synthesis example 1 except that 2 g and 174.3 g of a 37% formalin aqueous solution were used. The molecular weight of the ballast resin (a) is 800
Met.

Ballast Resin Synthesis Example 2 475.2 g of m-cresol, oxalic acid dihydrate 15
g, a ballast resin (b) was obtained in the same manner as in Novolak resin synthesis example 4 except that 196.4 g of a 37% aqueous formalin solution was used. The molecular weight of the ballast resin (b) was 986.

Ballast Resin Synthesis Example 3 m-cresol 324 was placed in a 1-liter eggplant-shaped flask.
g, 30 g of oxalic acid dihydrate, 3 ml of 35% hydrochloric acid and 300 ml of ethanol, and 117.5 of 90% acetaldehyde was added dropwise with stirring at room temperature. Thereafter, the oil bath temperature was maintained at 100 ° C., and the mixture was heated under reflux for 5 hours to carry out the reaction. went. After completion of the reaction, the reaction solution was diluted with 300 ml of ethanol and then dropped into 3 liters of water to precipitate crystals.
The obtained crystal was collected by filtration, washed three times with 3 liters of water, and dried to obtain a ballast resin (c). The molecular weight of the ballast resin (c) was 1058.

Synthesis Example 1 of Photosensitive Agent 39.4 g of ballast resin (b) and 58.0 g of 1,2-naphthoquinonediazide-5-sulfonyl chloride were dissolved in a mixed solvent of 240 ml of acetone and 65 ml of N-methylpyrrolidone. .1 g was added dropwise and reacted at room temperature for 2 hours, and then the reaction solution was filtered to remove triethylamine hydrochloride. The filtrate was added to 1 liter of water, and the precipitated crystals were collected by filtration, washed with water, and dried, and the sensitizer (P
-1) was obtained. The esterification ratio of the photosensitizer (P-1) was 65.
%.

Photosensitizer Synthesis Example 2 32.3 g of ballast resin (a) and 35.0 g of 1,2-naphthoquinonediazide-5-sulfonyl chloride were dissolved in a mixed solvent of 180 ml of acetone and 50 ml of N-methylpyrrolidone, and triethylamine 13 was dissolved. Except for dropping 0.4 g, a photosensitive agent (P-
2) was obtained. Esterification ratio of photosensitizer (P-2) is 50%
It is.

Photosensitive Agent Synthesis Example 3 31.7 g of ballast resin (c) and 29.0 g of 1,2-naphthoquinonediazide-5-sulfonyl chloride were dissolved in a mixed solvent of 160 ml of acetone and 44 ml of N-methylpyrrolidone, and triethylamine 11 Sensitizer (P-) in the same manner as in sensitizer synthesis example 1 except that 0.7 g was dropped.
3) was obtained. Esterification ratio of photosensitizer (P-3) is 45%
It is.

Photosensitive Agent Synthesis Example 4 2,3,4,4'-Tetrahydroxybenzophenone 1
2.3 g and 53.7 g of 1,2-naphthoquinonediazide-5-sulfonyl chloride were added to 1,4-dioxane 20
A photosensitizer (P-4) was obtained in the same manner as in Photosensitizer Synthesis Example 1, except that it was dissolved in a mixed solvent of 0 ml and N-methylpyrrolidone 50 ml, and 20.2 g of triethylamine was added dropwise.
The esterification ratio of the photosensitizer (P-4) is 100%.

Photosensitizer Synthesis Example 5 12.1 g of 2,2 ', 3,4,4'-pentahydroxybenzophenone and 1,2-naphthoquinonediazide-5
-Sulfonyl chloride (56.4 g) was dissolved in a mixed solvent of 1,4-dioxane (200 ml) and N-methylpyrrolidone (50 ml), and 23.2 g of triethylamine was dropped. 5) was obtained. The esterification ratio of the photosensitizer (P-5) is 84%.

Preparation Example 1 of Photosensitive Resin Composition Novolak resin (a) as alkali-soluble resin
708 g and 2.542 g of the photosensitizer (P-1) were dissolved in 37.25 g of methyl 3-methoxypropionate.
The mixture was filtered through a 2 μm membrane filter to obtain a photosensitive resin composition (PR-1).

Preparation Examples 2 to 14 of Photosensitive Resin Compositions
, Except that they were combined in the proportions shown in the above, in the same manner as in the photosensitive resin composition preparation example 1, the photosensitive resin compositions (PR-2) to
(PR-14) was obtained.

Examples 1 to 10 and Comparative Examples 1 to 4 The photosensitive resin compositions (PR-1) to (PR-14) were patterned by the following patterning method, and the sensitivity, critical resolution and exposure margin were evaluated. The results are shown in Table-2. In Table 2, the following symbols and terms have the following meanings, respectively.

[0049]

[Table 2] Eth: The minimum exposure required to completely dissolve the exposed area of 2 mm square to the substrate with the alkaline developer is indicated by the exposure time. E _O : The line & space pattern is formed on a 0.6 μm wide mask. When the exposure ratio is 1: 1, the exposed amount and the line width between the unexposed portion and the line width of the unexposed portion are 1: 1 by developing with an alkali developer after exposure. The exposure amount is indicated by the exposure time. Minimum line & space pattern resolvable in E _O Exposure margin: E _O / Eth value

<Patterning method> After applying the photosensitive resin composition to a silicon wafer by a spin coater,
The mixture was heated on a hot plate at 80 ° C. for 90 seconds to remove the solvent and form a 1.22 μm-thick photoresist coating film. This was used as a Nikon i-line stepper (NA = 0.
After exposure at 5), 9 on a hot plate at 110 ° C.
After heating for 0 second, the film was immersed in a 2.38% aqueous solution of tetramethylammonium hydroxide at 23 ° C. for 60 seconds and developed.

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[Table 3]

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[Table 4]

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The photosensitive resin composition of the present invention has a high resolution and a large exposure margin by using a specific novolak resin as the alkali-soluble resin, and is particularly useful as a photoresist.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-84414 (JP, A) JP-A-2-10348 (JP, A) JP-A-5-32751 (JP, A) JP-A-5-32751 61195 (JP, A) JP-A-5-34910 (JP, A) JP-A-5-204143 (JP, A) JP-A-4-500533 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) G03F ^7/ 00-7/42

Claims (3)

(57) [Claims] 1. A photosensitive resin composition comprising an alkali-soluble resin, a quinonediazide-based photosensitive compound and a solvent as main components, wherein the alkali-soluble resin is at least one phenolic compound represented by the following general formula [A]: (A) Formaldehyde and (b) a polycondensate of at least one ketone or aldehyde represented by the following general formula [B], and a mixture of the formaldehyde (a) with the ketone or aldehyde (b) A photosensitive resin composition having a ratio (molar ratio) of (a) / (b) of 1/99 to 99/1. Embedded image Embedded image Wherein R ¹ is R ² , OR ³ , COOR ⁴ or CH ₂ C
It represents a group represented by OOR ^5, wherein R ² is 1 to the number of carbon atoms
R ³ , R ⁴ and R ⁵ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n represents 0 to 4;
When n is 2 or 3, a plurality of R ¹ may be the same or different, and R ⁶ and R ⁷ each independently represent a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms. But,
R ⁶ and R ⁷ are not hydrogen atoms at the same time ]. 2. The photosensitive resin composition according to claim 1, wherein (b) is at least one selected from acetaldehyde, propionaldehyde and a mixture thereof. 3. A mixing ratio (molar ratio) of (a) and (b).
The photosensitive resin composition according to claim 1 or 2, wherein (a) / (b) is 50/50 to 90/10.