TWI631101B - Method for purifying cresols and method for producing novolac resin for photosensitive resin composition - Google Patents

Abstract

The present invention provides a purification method for purifying fractionated cresol obtained from tar distillation to produce cresols suitable for use as a novolak resin for a photosensitive resin composition, and using the photosensitivity of purified cresol purified by the purification method A method for producing a novolak resin for a resin composition, and a photosensitive resin composition containing the novolak resin produced by the production method.

The method for purifying cresols according to the present invention includes a removing step of removing basic substances in fractionated cresol obtained by distillation of tar. In this removal step, the fractionated cresol is washed with an aqueous solution of an acidic substance, or an acidic substance is added to the fractionated cresol, followed by re-distillation.

Description

Method for purifying cresols and method for producing novolac resin for photosensitive resin composition

The present invention relates to a method for purifying cresols used in the production of novolac resins for photosensitive resin compositions, a method for producing novolak resins for photosensitive resin compositions using purified cresol purified by the purification method, and A photosensitive resin composition containing a novolak resin manufactured by this manufacturing method.

In the past, positive-type photosensitive resin compositions containing novolac resins and quinoline diazide-containing compounds were materials having excellent sensitivity, resolution, and heat resistance, and have been widely and practically supplied to semiconductor integrated circuits ( IC) manufacturing and other fields.

Among these, novolak resins are generally synthesized by a condensation reaction between cresols and aldehydes and / or ketones. In addition, as cresols, chemical synthesizers are generally used. For example, o-cresol among the three isomers of cresol can be produced by a phenol methylation method using phenol and methanol as raw materials. Moreover, m-cresol and p-cresol can be oxidized by the toluene isopropyl method (isopropyl) by oxidizing isomenyl toluene (cymene) obtained from toluene and propylene. Based on the toluene method).

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Unexamined Patent Publication No. 9-53080

Therefore, cresols are contained in tar as tar acid, and can be obtained by distillation and purification of tar. However, tar also contains basic substances such as pyridine, methylpyridine, and aniline, which are known to remain in fractionated cresol. Therefore, various methods for removing the alkaline substance have been proposed. For example, Patent Document 1 proposes a method in which an aqueous solution of an alkali hydroxide is added to tar acid to form an aqueous solution of a tar salt, and the aqueous solution is brought into contact with activated carbon to thereby remove impurities such as tar alkali.

However, according to the review by the present inventors, it is necessary to almost completely remove the alkaline substances in the fractionated cresol when using a novolak resin made of cresol in a photosensitive resin composition. insufficient.

The present invention has been made in view of this past situation, and an object thereof is to provide a method for purifying cresols that can be used to purify fractionated cresol obtained from tar distillation and to produce a novolac resin used as a photosensitive resin composition. A method for producing a novolak resin for a photosensitive resin composition using purified cresol purified by the purification method, and containing the same The photosensitive resin composition of a novolak resin manufactured by this manufacturing method.

The present inventors have repeatedly and actively studied to achieve the above-mentioned object. As a result, it was found that by removing a basic substance in fractionated cresol obtained by tar distillation by a specific method, a novolak resin suitable as a photosensitive resin composition can be produced, and the present invention has been completed. Specifically, the present invention provides the following.

The first aspect of the present invention is a purification method, which is a method for purifying cresols used in the production of novolak resins for photosensitive resin compositions, and is characterized by including a base in fractionated cresol obtained by distilling tar A step of removing the volatile substances. The step of rinsing is to wash the aforementioned fractionated cresol with an acidic aqueous solution, or add an acidic substance to the aforementioned fractionated cresol, followed by re-distillation.

A second aspect of the present invention is a manufacturing method, which is a method for manufacturing a novolac resin for a photosensitive resin composition, and is characterized in that it includes In the reaction step, the above-mentioned cresols contain purified cresol purified by the purification method according to the first aspect of the present invention.

A third aspect of the present invention is a photosensitive resin composition characterized by containing a novolac resin manufactured by the manufacturing method of the second aspect of the present invention.

According to the present invention, a purification by tar distillation can be provided The obtained fractionated cresol can be used as a method for purifying cresols suitable as a novolak resin for a photosensitive resin composition, and a phenol for a photosensitive resin composition using purified cresol purified by the purification method. A method for producing a varnish resin, and a photosensitive resin composition containing a novolak resin produced by the method.

<Purification method of cresols>

The method for purifying cresols according to the present invention includes a removing step of removing alkaline substances in fractionated cresol obtained by tar distillation.

The above-mentioned fractionated cresol is not particularly limited, and a fractionated cresol obtained by a conventional method may be used, but among them, m-p-cresol and p-cresol as a main component have an alkali in a mixture / pair (m / p) mixture. The content of sexual substances tends to be large. Therefore, the effect is higher especially when using the m / p mixture.

The first method for removing alkaline substances is to wash the fractionated cresol with an aqueous solution of an acidic substance. That is, the aqueous solution of the fractionated cresol and the acidic substance is mixed to transfer the basic substance in the fractionated cresol to the aqueous phase, and then the basic substance in the fractionated cresol can be removed by liquid separation.

As the acidic substance, inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, or organic acids such as oxalic acid and acetic acid are mentioned, but inorganic acids are preferred, more preferably strong acids of inorganic acids, more preferably hydrochloric acid, sulfuric acid, and most preferably hydrochloric acid. . Moreover, although the concentration of the acidic substance varies with the content of the basic substance in the fractionated cresol, Different, but it is usually 0.1 to 20% by mass, preferably 0.5 to 15% by mass.

The amount of the aqueous solution of the acidic substance with respect to the fractionated cresol is not particularly limited, but it is usually 5 to 500% by mass, preferably 10 to 300% by mass.

In order to improve liquid separation, it is preferable to mix an organic solvent with the fractionated cresol in advance. Examples of the organic solvent include butyl acetate, toluene, xylene, hexane, heptane, and cyclohexane. The amount of the organic solvent used is not particularly limited, and it is usually 0.5 to 5 times the mass ratio to the fractionated cresol.

The specific liquid separation method may be a continuous method or a batch method. The continuous method uses a mixer settler type or a multi-stage extraction device of the tower type to continuously feed fractionated cresol (or a mixed solvent of fractionated cresol and an organic solvent) and an aqueous solution of an acidic substance to extract and remove the fractionated methyl alcohol. Basic substances in phenol. On the other hand, the batch method is a method of mixing and stirring and fractionating cresol (or a mixed solvent of cresol and an organic solvent) and an aqueous solution of an acidic substance, followed by standing and separating.

In addition, the second method of removing alkaline substances is to add an acidic substance to fractionated cresol, and then re-distill. That is, the basic substance in the fractionated cresol can be removed by adding an acidic substance to the fractionated cresol to form a salt, and then re-distilling according to a common method.

Examples of the acidic substance to be added include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, and organic acids such as oxalic acid and acetic acid. However, inorganic acids are preferred, hydrochloric acid and sulfuric acid are more preferred, and hydrochloric acid is most preferred. In addition, the addition amount of the acidic substance varies with the content of the basic substance in the fractionated cresol, but it is usually 0.5 to 20 mole%, preferably 1.0 to 10 mole%.

Times of washing and fractionating cresol with aqueous solution of acidic substance (Number of liquid separations) or after adding an acidic substance to the fractionated cresol, the number of times of re-distillation is appropriately determined according to the content of the basic substance in the fractionated cresol or the final target concentration. According to the review by the inventors, since the content of pyridine and 2-methylpyridine in the basic substances present in fractionated cresol is significantly larger, it is appropriate to continue the removal step until the contents of pyridine and 2-methylpyridine are respectively It is preferably less than 2 ppm, preferably less than 1 ppm, and more preferably 0 ppm (that is, the detection limit is not reached).

In addition, since the purification method of the present invention has high removal efficiency of the alkaline substance, it can almost completely remove the alkaline substance in a shorter time than the conventional method.

<Manufacturing method of novolac resin for photosensitive resin composition>

The method for producing a novolak resin for a photosensitive resin composition of the present invention includes a reaction step of reacting cresols with aldehydes and / or ketones in the presence of a catalyst. In addition to cresols, this reaction step may also allow phenols other than cresols to react with aldehydes and / or ketones.

The above cresols can be purified using the purification method of the present invention Purified cresol. In addition, in order to adjust characteristics such as sensitivity, cresols obtained by chemical synthesis may be further used. 50% by mass or more of cresols used in one embodiment is a purified cresol purified by the purification method of the present invention.

Phenols other than the above-mentioned cresols are listed as phenol; Dimethyl phenol, 2,4-dimethylphenol, 2,5-dimethylphenol, 2,6-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, etc. Phenols; o-ethylphenol, m-ethylphenol, p-ethylphenol, 2-isopropylbenzene Alkyl phenols such as phenol, 3-isopropylphenol, 4-isopropylphenol, o-butylphenol, m-butylphenol, p-butylphenol, and p-thirdbutylphenol; 2, Trialkylphenols such as 3,5-trimethylphenol, 3,4,5-trimethylphenol; resorcinol, catechol, hydroquinone, hydroquinone monomethyl ether , Polyhydric phenols such as pyrogallol, phloroglucinol; alkyl polyphenols such as alkyl resorcinol, alkyl catechol, and alkyl hydroquinone (All alkyl groups have 1 to 4 carbons); α-naphthol, β-naphthol, phenylphenol, bisphenol A, and the like. These phenols may be used alone or in combination of two or more. Among these phenols, 2,5-dimethylphenol, 3,5-dimethylphenol, and 2,3,5-trimethylphenol are preferred.

The above aldehydes are listed as formaldehyde, paraformaldehyde, acetaldehyde, and propane Aldehyde, butyraldehyde, trimethylacetaldehyde, acrolein, crotonaldehyde, cyclohexanal, furfural, furyl acrolein, benzaldehyde, terephthalaldehyde, phenylacetaldehyde, α-phenylpropanal, β- Phenylpropanal, o-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, o-chlorobenzaldehyde, M-chlorobenzaldehyde, p-chlorobenzaldehyde, cinnamaldehyde, etc. These aldehydes can be used alone or in combination of two or more. Among these aldehydes, formaldehyde is preferred in terms of easy availability.

The ketones are listed as acetone, methyl ethyl ketone, and diethyl Ketones, diphenyl ketones, etc. These ketones can be used alone or in combination of two or more.

The above acid catalysts are exemplified by hydrochloric acid, sulfuric acid, nitric acid, and phosphorus. Acids, phosphorous acid and other inorganic acids; formic acid, oxalic acid, acetic acid, diethylsulfur Organic acids such as acids and p-toluenesulfonic acid; metal salts such as zinc acetate. These acid catalysts can be used alone or in combination of two or more.

Mass average molecular weight of the novolac resin thus obtained It is not particularly limited, but is preferably 2,000 to 30,000, and more preferably 3,000 to 25,000. By setting the mass average molecular weight to 2000 or more, the film-forming property of the prepared photosensitive resin composition is improved, and the heat resistance is also improved. In addition, by setting the mass average molecular weight to 30,000 or less, the sensitivity of the prepared photosensitive resin composition can be improved.

The mass average molecular weight of the novolak resin can be adjusted by performing appropriate separate operations to remove those with low molecular weight.

In addition, the dispersion of novolac resin [mass average molecule The amount / number average molecular weight (Mw / Mn)] is preferably 5 or less, more preferably 3 or less. When the degree of dispersion is 5 or less, the pattern shape when forming a resin pattern using the prepared photosensitive resin composition becomes favorable. The degree of dispersion is substantially 1 or more.

<Photosensitive resin composition>

The photosensitive resin composition of this invention contains the novolak resin manufactured by the manufacturing method of this invention. The content of the novolak resin is preferably 50 to 95% by mass, more preferably 60 to 90% by mass, relative to the solid content of the photosensitive resin composition. By falling within the above-mentioned range, it is easy to balance the developability.

In addition, the photosensitive resin composition of the present invention contains a quinone Diazide-based compounds serve as sensitizers. The quinonediazide-containing compound It is preferably a complete ester or a partial ester of a phenol compound and a quinonediazide-containing sulfonic acid compound. Such a quinonediazide-containing compound can be obtained by allowing a phenol compound and a quinonediazide-containing sulfonic acid compound in a suitable solvent such as dioxane in the presence of a base such as triethanolamine, alkali carbonate, or bicarbonate. It is obtained by condensation, complete esterification or partial esterification.

The phenol compound is preferably a compound represented by the following formula (1) 组合。 The compound.

In the above formula (1), R ¹ to R ⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. . R ⁹ to R ¹¹ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Q represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms bonded to R ⁹ , or a group represented by the following formula (2). a and b each independently represent an integer of 1 to 3, and d and n each independently represent an integer of 0 to 3.

In the formula (2), R ¹² and R ¹³ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. . c represents an integer from 1 to 3.

Specific examples of the phenol compound are polyhydroxybenzophenones such as 2,3,4, -trihydroxybenzophenone and 2,3,4,4'-tetrahydroxybenzophenone; Phenyl) methane, bis (4-hydroxy-3-methylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,3,5-trimethylphenyl) -2-hydroxyphenyl Methane, bis (4-hydroxy-3,5-dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3-hydroxyphenylmethane, Bis (4-hydroxy-3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -4-hydroxyphenylmethane, bis ( 4-hydroxy-2,5-dimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4- Hydroxy-3,5-dimethylphenyl) -3,4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3,4-dihydroxyphenylmethane, Bis (4-hydroxy-2,5-dimethylphenyl) -2,4-dihydroxyphenylmethane, bis (4-hydroxyphenyl) -3-methoxy-4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3-hydroxyphenylmethane , Bis (5-cyclohexyl-4-hydroxy- 2-methylphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3,4-dihydroxyphenylmethane, 4,4 '-[ (2-hydroxyphenyl) methylene] bis (2,3,6-trimethylphenol), 5,5'-dicyclohexyl-4,4 ', 3 ", 4" -tetrahydroxy-2, 2'-dimethyltriphenylmethane and other phenolic compounds; 2,4-bis (3,5-dimethyl-4-hydroxybenzyl) -5-hydroxyphenol, 2,6-bis (2, 5-dimethyl-4-hydroxybenzyl) -4-hydroxyphenol, etc. Body phenol compounds; 1,1-bis [3- (2-hydroxy-5-methylbenzyl) -4-hydroxy-5-cyclohexylphenyl] isopropane, bis [2,5-dimethyl-3 -(4-hydroxy-5-methylbenzyl) -4-hydroxyphenyl] methane, bis [2,5-dimethyl-3- (4-hydroxybenzyl) -4-hydroxyphenyl] methane, Bis [3- (3,5-dimethyl-4-hydroxybenzyl) -4-hydroxy-5-methylphenyl] methane, bis [3- (3,5-dimethyl-4-hydroxybenzyl) ) -4-hydroxy-5-ethylphenyl] methane, bis [3- (3,5-diethyl-4-hydroxybenzyl) -4-hydroxy-5-methylphenyl] methane, bis [3- (3,5-Diethyl-4-hydroxybenzyl) -4-hydroxy-5-ethylphenyl] methane, bis [2-hydroxy-3- (3,5-dimethyl-4 -Hydroxybenzyl) -5-methylphenyl] methane, bis [2-hydroxy-3- (2-hydroxy-5-methylbenzyl) -5-methylphenyl] methane, bis [4-hydroxyl -3- (2-hydroxy-5-methylbenzyl) -5-methylphenyl] methane, bis [2,5-dimethyl-3- (2-hydroxy-5-methylbenzyl)- 4-hydroxyphenyl] methane and other linear tetranuclear phenolic compounds; 2,4-bis [2-hydroxy-3- (4-hydroxybenzyl) -5-methylbenzyl] -6-cyclohexylphenol, 2,4-bis [4-hydroxy-3- (4-hydroxybenzyl) -5-methylbenzyl] -6-cyclohexylphenol, 2,6-bis [2,5-dimethyl-3- (2-hydroxy-5-methylbenzyl) -4 -Hydroxybenzyl] -4-methylphenol and other linear pentameric phenol compounds; bis (2,3,4-trihydroxyphenyl) methane, bis (2,4-dihydroxyphenyl) methane, 2, 3,4-trihydroxyphenyl-4'-hydroxyphenylmethane, 2- (2,3,4-trihydroxyphenyl) -2- (2 ', 3', 4'-trihydroxyphenyl) propane , 2- (2,4-dihydroxyphenyl) -2- (2 ', 4'-dihydroxyphenyl) propane, 2- (4-hydroxyphenyl) -2- (4'-hydroxyphenyl) Propane, 2- (3-fluoro-4-hydroxyphenyl) -2- (3 -'- fluoro-4'-hydroxyphenyl) propane, 2- (2,4-dihydroxyphenyl) -2- ( 4'-hydroxyphenyl) propane, 2- (2,3,4-trihydroxyphenyl) -2- (4'-hydroxyl Phenyl) propane, 2- (2,3,4-trihydroxyphenyl) -2- (4'-hydroxy-3 ', 5'-dimethylphenyl) propane, 4,4'-[1 -[4- [1- (4-hydroxyphenyl) -1-methylethyl] phenyl] ethylene] bisphenol, 4,4 '-[1- [4- [2- [4-hydroxy Bisphenol compounds such as phenyl] -2-propyl] phenyl] ethylene] bisphenol; 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis ( 4-hydroxyphenyl) ethyl] benzene, 1- [1- (3-methyl-4-hydroxyphenyl) isopropyl] -4- [1,1-bis (3-methyl-4-hydroxy Polynuclear branched nested compounds such as phenyl) ethyl] benzene; condensed phenol compounds such as 1,1-bis (4-hydroxyphenyl) cyclohexane; etc.

These phenol compounds may be used alone or in combination of two or more.

The quinonediazide-containing sulfonic acid compounds are listed as naphthoquinone-1,2-diazide-5-sulfonic acid, naphthoquinone-1,2-diazide-4-sulfonic acid, and o-anthraquinone Diazidesulfonic acid, etc.

The content of the diazide group-containing compound is preferably 5 to 50 parts by mass, more preferably 5 to 25 parts by mass, relative to 100 parts by mass of the novolac resin. By setting it as the said range, the sensitivity of a photosensitive resin composition becomes favorable.

Moreover, it is preferable that the photosensitive resin composition of this invention contains the said phenol compound as a sensitizer. The content of the phenol compound is preferably 5 to 50 parts by mass, more preferably 10 to 40 parts by mass, with respect to 100 parts by mass of the novolac resin. By setting it as the said range, the sensitivity of the photosensitive resin composition becomes favorable, and the film fall at the time of image development can also be suppressed.

In addition, the photosensitive resin composition of the present invention may be used as required. Contains surfactant and UV absorber. Examples of the surfactant include a fluorine-based surfactant. UV absorbers are listed as 2,2 ', 4,4'-tetrahydroxybenzophenone, 4-dimethylamino-2', 4'-dihydroxybenzophenone, 5-amino-3-methyl -Yl-1-phenyl-4- (4-hydroxyphenylazo) pyrazole, 4-dimethylamino-4'-hydroxyazobenzene, 4-diethylaminoazobenzene, 4-diethyl Amino-4'-ethoxyazobenzene, curcumin, and the like.

Furthermore, if necessary, conventional additives such as addition resins, plasticizers, stabilizers, adhesives, and contrast improvers may be contained.

The photosensitive resin composition of the present invention is preferably used as a solution dissolved in an appropriate organic solvent to improve coatability and adjust viscosity.

Examples of organic solvents include ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, and 2-heptanone; ethylene glycol, propylene glycol, diethylene glycol, ethylene glycol monoacetate, Polyols such as propylene glycol monoacetate, diethylene glycol monoacetate, or monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, or monophenyl ether, and the like Derivatives; cyclic ethers such as dioxane; esters such as ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, ethyl methoxypropionate, and the like. These organic solvents may be used alone or as a mixture of two or more.

The content of the organic solvent is not particularly limited, and is appropriately set depending on the concentration that can be applied to the substrate and the like, and the thickness of the coating film. Specifically, the amount of the solid content concentration of the photosensitive resin composition is preferably 10 to 50% by mass, and more preferably 20 to 40% by mass.

The photosensitive resin composition of the present invention can be prepared by mixing and stirring the above components. If necessary, you can further use a screen, thin Filtration by a membrane filter, etc.

[Example]

Hereinafter, examples of the present invention will be described, but the scope of the present invention is not limited to these examples.

<Purification of Fractionated Cresol> [Untreated 1, 2]

Preparation of Fumei Chemical between -p-cresol (m-cresol / p-cresol = 66/33 (molar ratio); untreated 1) and between different batches made by the same company-p-cresol (M-cresol / p-cresol = 66/33 (molar ratio; untreated 2)) was used as the untreated fractionated cresol. Next, gas chromatography mass analysis (manufactured by PerkinElmer) was used to measure pyridine and 2-methyl The content of methylpyridine (detection limit <0.1 ppm). The results are shown in Table 1 below.

[Comparative purification example 1]

In a flask equipped with a thermometer and a reflux tube, 1800 g of untreated 1 fractionated cresol was fed. While raising the temperature to a maximum of 130 ° C. and flowing out an initial flow of 180 g, the main distillation fraction was taken at a reflux ratio of 10 to 20 to obtain 1550 g Of purified cresol. Next, the content of pyridine and 2-methylpyridine in the purified cresol was measured in the same manner as described above. The results are shown in Table 1 below.

[Purification Example 1]

700 kg of fractionated cresol of untreated 1 and 700 kg of butyl acetate, Then, 1400 kg of a 1% by mass aqueous hydrochloric acid solution was mixed and stirred for 60 minutes. After standing, the organic phase was separated. 1400 kg of a 1% by mass aqueous hydrochloric acid solution was mixed with this organic phase and stirred for 60 minutes. After standing, the organic phase was separated. 1400 kg of pure water was mixed into the organic phase, and the mixture was stirred for 30 minutes. After standing, the organic phase was separated. Repeated washing operation was repeated 3 times with pure water. Next, the organic phase was concentrated to 1% by mass of water and 3% by mass of butyl acetate to obtain purified cresol. Next, the content of pyridine and 2-methylpyridine in the purified cresol was measured in the same manner as described above. The results are shown in Table 1 below.

[Purification Example 2]

Into a flask equipped with a thermometer and a reflux tube, feed 1000 g of untreated 1 fractionated cresol and hydrochloric acid (with moles such as pyridine in fractionated cresol), and raise the temperature to a maximum of 130 ° C. while letting out an initial flow of 50 g. The main distillation fraction was taken under the conditions of a reflux ratio of 10 to 20 to obtain 730 g of purified cresol. Next, the content of pyridine and 2-methylpyridine in the purified cresol was measured in the same manner as described above. The results are shown in Table 1 below.

As can be understood from Table 1, Contains about 200 ppm of pyridine and 2-methylpyridine. Although the content of 2-methylpyridine can be significantly reduced by re-distillation as in Comparative Purification Example 1, the content of pyridine is hardly reduced. In contrast, for example, in Purification Examples 1 and 2, the untreated fractionated cresol was washed with an aqueous solution of hydrochloric acid, or after adding hydrochloric acid to the fractionated cresol, by re-distillation, the pyridine and 2 in the fractionated cresol could be almost completely removed. -Methylpyridine.

<Production of Novolac Resin and Preparation of Photosensitive Resin Composition> [Example 1]

To the m-cresol / p-cresol / 3,5-xylenol = 50/30/20 (molar ratio), the purified fraction of cresol in Purification Example 1 was added with a chemically synthesized compound. -Cresol and 3,5-dimethylphenol. Next, using oxalic acid as an acid catalyst and formalin as a condensing agent, a condensation reaction was performed in a usual manner to obtain a novolac resin. In addition, the condensation reaction conditions are conditions for obtaining a novolac resin having a mass average molecular weight (Mw) of 8,000 when cresol is used instead of fractionated cresol when using chemically synthesized products.

100 parts by mass of the novolac resin was added as follows A photosensitive resin, a sensitizer, and a surfactant are added, and 2-heptanone is added and mixed so that the solid content concentration becomes 35% by mass, thereby preparing a photosensitive resin composition.

‧Photosensitizer

4,4 '-[(2-hydroxyphenyl) methylene] bis (2,3,6-trimethylphenol) -naphthoquinone-1,2-diazide-5-sulfonic acid (mono ~ C) Ester ... 21 Portion

5,5'-dicyclohexyl-4,4 ', 3 ", 4" -tetrahydroxy-2,2'-dimethyltriphenylmethane-naphthoquinone-1,2-diazide-5- Sulfonic acid (mono ~ tetra) ester ... 4.3 parts by mass

‧Sensitizer

4,4 '-[1- [4- [2- [4-hydroxyphenyl] -2-propyl] phenyl] ethylene] bisphenol ... 35 parts by mass

‧Surface active agent

Perfluoroalkyl group-containing oligomer ... 8 parts by mass

[Example 2]

A chemically synthesized product was added to the purified fractionated cresol in Purification Example 1 so that m-cresol / p-cresol / 3,5-dimethylphenol = 50/30/20 (molar ratio). P-cresol and 3,5-dimethylphenol. Next, using oxalic acid as an acid catalyst and formalin as a condensing agent, a condensation reaction was performed in a usual manner to obtain a novolac resin. The condensation reaction conditions are conditions for obtaining a novolac resin having a mass average molecular weight of 4500 when cresol is used instead of fractionated cresol.

The following photosensitizer, sensitizer, and surfactant were added to 100 parts by mass of the novolac resin, and 2-heptanone was added and mixed so that the solid content concentration became 32% by mass to prepare a photosensitive resin composition.

‧Photosensitizer

4,4 '-[(2-hydroxyphenyl) methylene] bis (2,3,6-trimethylphenol) -naphthoquinone-1,2-diazide-5-sulfonic acid (mono ~ C) Ester ... 21 parts by mass

5,5'-dicyclohexyl-4,4 ', 3 ", 4" -tetrahydroxy-2,2'-dimethyltriphenylmethane-naphthoquinone-1,2-diazide-5- Sulfonic acid (mono ~ tetra) ester ... 4.3 parts by mass

‧Sensitizer

4,4 '-[1- [4- [2- [4-hydroxyphenyl] -2-propyl] phenyl] ethylene] bisphenol ... 35 parts by mass

‧Surface active agent

Perfluoroalkyl group-containing oligomer ... 8 parts by mass

[Comparative Examples 1, 2]

A novolac resin was prepared in the same manner as in Examples 1 and 2 except that the fractionated cresol purified in Purification Example 1 was replaced with the fractionated cresol untreated 1. The photosensitive resin composition was prepared. The mass average molecular weight of the target novolak resin was 8000 in Comparative Example 1 and 4500 in Comparative Example 2.

[Comparative Examples 3 and 4]

Except that the amount of the acid catalyst used in the production of the novolac resin was increased by three times, the rest was produced in the same manner as in Comparative Examples 1 and 2, and a photosensitive resin composition was prepared. The mass average molecular weight of the target novolak resin was 8,000 in Comparative Example 3 and 4500 in Comparative Example 4.

[Comparative Example 5]

A novolac resin was produced in the same manner as in Example 1 except that the fractionated cresol purified in Purification Example 1 was replaced with the fractionated cresol of Untreated 2. The mass average molecular weight of the target novolak resin was 8,000.

[Example 3]

A chemically synthesized product, p-cresol, was added to the purified fractionated cresol in Purification Example 2 so that m-cresol / p-cresol = 60/40 (molar ratio). Next, using oxalic acid as an acid catalyst and formalin as a condensing agent, a condensation reaction was performed in a usual manner to obtain a novolac resin. In addition, the condensation reaction conditions are conditions for obtaining a novolac resin having a mass average molecular weight (Mw) of 16,300 when cresol is used instead of fractionated cresol when using a chemically synthesized product.

100 parts by mass of the novolac resin was added as follows The photosensitive resin, the additive, and the surfactant are prepared by adding a mixed solvent of ethyl lactate / butyl acetate = 90/10 (mass ratio) so that the solid content concentration becomes 20% by mass, thereby preparing a photosensitive resin composition.

‧Photosensitizer

6-diazo-5,6-dihydro-5-oxo-1-naphthalenesulfonate of 2,3,4-trihydroxybenzophenone ... 27 parts by mass

‧additive

2,3,4-trihydroxybenzophenone ... 12.7 parts by mass

‧Surface active agent

Perfluoroalkyl-containing oligomers ... 5.1 parts by mass

[Comparative Example 6]

A novolac resin was produced in the same manner as in Example 3, except that the fractionated cresol in Purification Example 2 was used instead of the fractionated cresol in Purification Example 2. The mass average molecular weight of the target novolak resin was 16,300.

[Comparative Example 7]

A novolac resin was produced in the same manner as in Example 3 except that the purified fractionated cresol in Comparative Purification Example 1 was used in place of the fractionated cresol purified in Purification Example 2. The mass average molecular weight of the target novolak resin was 16,300.

<Evaluation of novolac resin and photosensitive resin composition> [Evaluation of mass average molecular weight (Mw) of novolac resin]

The mass average molecular weights of the novolak resins obtained in Examples 1 to 3 and Comparative Examples 1 to 7 were measured. The ratio (%) to the mass average molecular weight of each target is shown in Table 2 below.

[Evaluation of alkali melting rate (ADR) of novolac resin]

The novolak resins obtained in Examples 1 to 3 and Comparative Examples 1 to 7 were each dissolved in propylene glycol monomethyl ether acetate to prepare a 25% by mass resin solution. This resin solution was coated on a silicon wafer and dried at 110 ° C. for 90 seconds to form a resin film having a film thickness of 1 μm. Subsequently, the resin film was immersed in a 2.38% by mass aqueous solution of tetramethylammonium for a certain period of time to determine the amount of change in the film thickness of the resin film.

In addition, in addition to the use of chemically synthesized cresols instead of fractionated distillates Except for phenol, the rest were manufactured in the same manner as in Examples 1 to 3, and novolac resins with mass average molecular weights of 4500, 8000, and 16300 were obtained. The film thickness variation of the resin film was also determined. Standard value of each molecular weight of 7.

The ratio (%) of the film thickness change amount to the standard value in Examples 1 to 3 and Comparative Examples 1 to 7 is shown in Table 2 below.

[Sensitivity evaluation of photosensitive resin composition]

The photosensitive resin composition prepared in Examples 1, 2, and Comparative Examples 1 to 4 was coated on a silicon wafer using a spin coater, and dried on a hot plate at 90 ° C for 90 seconds to obtain a film thickness of 1.05. μm resin film. Then, use Reduction projection exposure device NSR-2005i10D (manufactured by NIKON), through a mask (reticle) corresponding to a 0.5 μm pattern with a line and space pattern of 1: 1, the resin is made at intervals of 0.1 second to 0.01 second After the film was exposed, a PEB (post-exposure heating) treatment was performed at 110 ° C for 90 seconds. Subsequently, a 2.38% by mass aqueous solution of tetramethylammonium was used to develop an exposed resin film at 23 ° C. for 60 seconds, and the resin film was washed with water for 30 seconds and dried to form a line and space pattern. Next, the optimal exposure time (Eop) for forming a masked line and a spatial pattern is obtained in milliseconds (ms) as an index of sensitivity.

In addition, Example 3 was prepared using a spin coater. The photosensitive resin composition was coated on a silicon wafer, and dried on a hot plate at 90 ° C. for 90 seconds to obtain a resin film having a film thickness of 1.26 μm. Next, use a ghi line mixed light source (however, light with a wavelength below h line (405 nm) is blocked by a filter), and pass through a 1.0 μm pattern mask (grating corresponding to the line and space pattern of 1: 1) ), And after exposing the resin film at intervals of 0.1 second to 0.01 second, a PEB (post-exposure heating) treatment was performed at 110 ° C. for 90 seconds. Subsequently, a 2.38% by mass aqueous solution of tetramethylammonium was used to develop an exposed resin film at 23 ° C. for 60 seconds, and the resin film was washed with water for 30 seconds and dried to form a line and space pattern. Next, the optimal exposure time (Eop) for forming a masked line and a spatial pattern is obtained in milliseconds (ms) as an index of sensitivity.

In addition, in addition to the use of chemically synthesized products of cresol instead of fractionated Except for phenol, the rest were produced in the same manner as in Examples 1 to 3, respectively, with novolac resins having a mass average molecular weight of 4500, 8000, and 16300, and the novolac resin was used. The resin was prepared in the same manner as in Examples 1 to 3 and Comparative Examples 1 to 4 to prepare a photosensitive resin composition. Next, the optimal exposure time (Eop) was obtained in the same manner as described above, and was used as a standard value for Examples 1 to 3 and Comparative Examples 1 to 4.

The ratio (%) of the optimal exposure time (Eop) to the standard value for Examples 1 to 3 and Comparative Examples 1 to 4 is shown in Table 2 below.

In Comparative Example 5, novolac resin was confirmed. Since the characteristics were inferior to those of Comparative Example 1, the evaluation of the photosensitive resin composition was not performed. In Comparative Examples 6 and 7, it was understood that the sensitivity characteristics were deteriorated from the results of the novolac resin, and the sensitivity and the evaluation of the heat resistance and resolution could not be adjusted as in other examples. Therefore, the evaluation of the photosensitive resin composition was not performed.

[Evaluation of heat resistance of photosensitive resin composition]

In order to adjust the sensitivity to the same degree, the photosensitive resin composition of Example 1 and the photosensitive resin composition of Example 2 were mixed at a mass ratio of 35:65. Similarly, the photosensitive resin composition of Comparative Example 1 and the photosensitive resin composition of Comparative Example 2 were mixed at a mass ratio of 84:16, and the photosensitive resin composition of Comparative Example 3 was mixed at a mass ratio of 12:88 and compared. The photosensitive resin composition of Example 4.

In addition, the photosensitive resin composition of Example 3 was used without mixing and adjustment.

Next, the obtained photosensitive resin group was spin-coated. The resultant (except Example 3) was coated on a silicon wafer, and dried on a hot plate at 90 ° C. for 90 seconds to obtain a resin film having a film thickness of 1.05 μm. then, After the resin film was exposed using a reduction projection exposure apparatus NSR-2005i10D (manufactured by NIKON Corporation), a PEB (post-exposure heating) process was performed at 110 ° C for 90 seconds. Subsequently, a 2.38% by mass aqueous solution of tetramethylammonium was used to develop an exposed resin film at 23 ° C. for 60 seconds, and the resin film was washed with water for 30 seconds and dried to form a 300 μm line pattern. Subsequently, the silicon wafer was heated at 130 ° C. for 5 minutes, and the cross-section of the line pattern was observed. Next, the corner holder of the 300 μm line pattern was marked as ○, and the corner of the 300 μm line pattern was rounded due to the heat flow, and the heat resistance was evaluated. The results are shown in Table 2 below.

The photosensitive resin composition of Example 3 was The heat resistance was evaluated as described above except that the thickness of the resin film was set to 1.26 μm, and a ghi mixed light source was used for exposure (however, light having a wavelength below h-line (405 nm) was blocked by a filter). The results are shown in Table 2 below.

[Analytical Evaluation of Photosensitive Resin Composition]

In order to adjust the sensitivity to the same degree, the photosensitive resin composition of Example 1 and the photosensitive resin composition of Example 2 were mixed at a mass ratio of 35:65. Similarly, the photosensitive resin composition of Comparative Example 1 and the photosensitive resin composition of Comparative Example 2 were mixed at a mass ratio of 84:16, and the photosensitive resin composition of Comparative Example 3 was mixed at a mass ratio of 12:88 and compared. The photosensitive resin composition of Example 4.

In addition, the photosensitive resin composition of Example 3 was used without mixing and adjustment.

Next, in addition to using the line and space width of 0.50 μm, 0.45μm, 0.40μm, 0.38μm, 0.36μm, 0.35μm or 0.32μm Except for the mask (raster), the rest are formed in the same way as the pattern formation method in the sensitivity evaluation described above (except for the third embodiment). Next, by confirming the presence or absence of residues in the space portion, the minimum resolvable minimum interval width was obtained. The results are shown in Table 2 below.

For the photosensitive resin composition of Example 3, except for using a mask (grating) with a line and space width of 1.0 μm, 0.8 μm, 0.6 μm, or 0.4 μm, the rest is the same as the pattern formation method in the above-mentioned sensitivity evaluation. Line and space patterns are also formed. Next, by confirming the presence or absence of residue in the space portion, the minimum resolvable minimum space width is obtained. The results are shown in Table 2 below.

As understood from Table 2, the use of almost complete removal of alkalines The mass average molecular weight and alkali dissolution rate of Examples 1 to 3 in which novolac resin was produced by high-quality fractional cresol distillation were almost as standard. In addition, the sensitivity of the photosensitive resin composition is almost as standard, and the heat resistance and resolution are also good. The analytical results of Example 3 were the same as those obtained when a cresol was used in place of fractionated cresol, which is a good result.

On the other hand, in Comparative Examples 1 and 2 in which novolac resin was produced using fractionated cresol of untreated 1, the mass average molecular weight and alkali dissolution rate greatly deviated from the standard values. In addition, the sensitivity of the photosensitive resin composition also largely deviated from the standard value, and the heat resistance and resolution were also inferior to those of Examples 1 and 2.

In addition, compared to Comparative Examples 1 and 2, the comparative examples 3 and 4 in which the amount of the acid catalyst was increased three times to produce a novolac resin, although the mass average molecular weight and alkali dissolution rate were almost as standard, the photosensitive resin composition The sensitivity of the object largely deviates from the standard value, and the heat resistance and resolution are also inferior to those of Examples 1 and 2.

In addition, Comparative Example 5 for the production of novolac resin using fractionated cresol of untreated 2; Comparative Example 6 for the production and use of comparative no. 1 of fractionated cresol of untreated 1; 2; In Comparative Example 7 in which novolac resin was produced by fractional distillation of cresol, both the mass average molecular weight and the rate of alkali dissolution were largely deviated from the standard values.

Claims (3)

A purification method, which is a method for purifying cresols used in the production of novolac resins for photosensitive resin compositions, and is characterized by including pyridine, methylpyridine, or aniline in fractionated cresols obtained by distilling tar. A step of removing the alkaline substance is performed. The step of removing the alkaline substance is washing the aforementioned fractionated cresol with an aqueous solution of hydrochloric acid or adding hydrochloric acid to the aforementioned fractionated cresol, followed by re-distillation. A manufacturing method is a method for manufacturing a novolak resin for a photosensitive resin composition, characterized in that it comprises a reaction step of reacting cresols with aldehydes and / or ketones in the presence of a catalyst, and the aforementioned cresol The class contains purified cresol purified by the purification method as claimed in claim 1. The method according to claim 2, wherein the reaction step is a reaction of the cresols and phenols other than the cresols with the aldehydes and / or the ketones.