JP4661064B2 - Method for producing phenolic resin for photoresist and photoresist composition - Google Patents

Description

  The present invention relates to a method for producing a phenol resin for photoresist and a resin composition for photoresist.

  In general, a positive photoresist uses a photosensitizer having a quinonediazide group such as a naphthoquinonediazide compound and an alkali-soluble resin (for example, a novolac-type phenolic resin). A positive photoresist having such a composition exhibits a high resolving power by developing with an alkaline solution after exposure, and is used for manufacturing semiconductors such as IC and LSI, display screen devices such as LCDs, and printing masters. Yes. In addition, novolac type phenolic resin has high dry etching resistance due to the structure having many aromatic rings against plasma dry etching. So far, novolac type phenolic resin and naphthoquinone diazide photosensitizer are used. Numerous positive photoresists have been developed and put into practical use and have achieved great results.

As the positive photoresist, a novolak type phenol resin obtained by reacting m / p-cresol and formaldehyde in the presence of an acid catalyst is generally used. In order to adjust or improve the characteristics of the photoresist, studies have been made on the ratio of m / p-cresol used as a raw material phenol, the molecular weight of the phenol resin, the molecular weight distribution, and the like.
However, in a photoresist to which a resin obtained by a general method from m / p-cresol and formaldehyde is applied, for example, in the LCD manufacturing process, a low-nuclear component (mainly binuclear) of a phenol resin in the photoresist. Sublimation of the component) causes the sublimate to accumulate and contaminate the production line, causing a reduction in product yield. For this reason, the reduction | decrease request | requirement of the binuclear component of a phenol resin has become very high.

Such a phenol resin having a small amount of a binuclear component is synthesized by a method such as solvent fractionation (for example, see Patent Document 1), removal of the dinuclear component by steam distillation (for example, see Patent Document 2), or the like. There are examples.
Solvent fractionation is a technique that utilizes the difference in solubility between good and poor solvents, but there is no clear difference in solubility between the low-nuclear components of the phenolic resin, so the binuclear component is selectively removed. Difficult to do. For this reason, excess resin was removed, resulting in a disadvantage that the batch yield was reduced and the production was not possible at a low cost.
In addition, since the removal efficiency of the dinuclear body is low, repeated operations are required, and a large amount of a solution of the removal component is generated, resulting in a high environmental load.

  On the other hand, the steam distillation method is a technique in which high-pressure steam is blown into the resin under vacuum conditions to forcibly remove the dinuclear component by azeotropic action, but there is a clear boiling point between the low-nuclear components of the phenol resin. Due to the difference, the selectivity for removing dinuclear components is high. However, not only is it necessary to have robust equipment that can withstand bumping and explosion phenomena that occur when steam is blown into high-temperature resin, but a large amount of high-pressure steam is generated to keep the resin at a high temperature for a long time. Not only can it be manufactured at low cost, such as the need for thermal energy, the generation of agglomerated water with dissolved binuclear components as industrial waste, and the technical and environmental aspects of implementation on an industrial scale. The production barrier was an influential barrier.

JP-T-2001-506294 Japanese Patent Application Laid-Open No. 11-246643

  The present invention provides a method for producing a phenol resin for a photoresist that can reduce contamination of a production line due to sublimates in a photoresist resin composition and improve productivity at a low cost, and this production method. The resin composition for photoresists using the obtained phenol resin for photoresists is provided.

Such an object is achieved by the following present inventions (1) to ( 7 ).
(1)
(A) performing a condensation reaction of phenols and aldehydes under reflux conditions;
(B) raising the temperature of the reaction system after the step (a) to remove moisture and unreacted monomers;
A method for producing a phenolic resin for photoresists, comprising:
In the step (a), 0.2 mol or more of oxalic acid is used with respect to 1 mol of the phenols,
In the step (b), 0.2 mol or more of oxalic acid is used with respect to 1 mol of the phenols used in the step (a).
(2)
(A) performing a condensation reaction of phenols and aldehydes under reflux conditions;
(B) raising the temperature of the reaction system after the step (a) to remove moisture and unreacted monomers;
A method for producing a phenolic resin for photoresists, comprising:
In the step (b), 0.2 mol or more of oxalic acid is used with respect to 1 mol of the phenols used in the step (a).
( 3 ) The above phenols are composed of m-cresol and p-cresol, and the weight ratio (m-cresol / p-cresol) is 9/1 to 2/8 (1) or (2) The manufacturing method of the phenol resin for photoresists of description.
( 4 ) The reaction molar ratio (F / P) between the phenols (P) and the aldehydes (F) is 0.5 to 1.0, according to any one of (1) to ( 3 ) above. A method for producing a phenolic resin for photoresist.
( 5 ) The method for producing a phenol resin for a photoresist according to any one of (1) to ( 4 ), wherein the aldehyde is formaldehyde.
( 6 ) The method for producing a phenol resin for a photoresist according to any one of (1) to ( 5 ), wherein the obtained phenol resin has the following characteristics.
(I) The binuclear component content is 5% or less of the entire resin.
(II) The weight average molecular weight measured by GPC is 1000-20000.
( 7 ) A photoresist resin composition comprising a photoresist resin, a photosensitive agent, and a solvent obtained by the production method according to any one of (1) to ( 6 ) above.

According to the present invention, it is possible to produce a phenol resin for a photoresist with less binuclear components at a lower cost and more easily than conventional methods. By using the photoresist resin composition using the phenol resin produced by the production method of the present invention, contamination of the production line is reduced in the LCD production process and the like.
In addition, it is expected to improve the yield when manufacturing a phenol resin for photoresist, and it is possible to reduce waste and reduce environmental burden.

Hereafter, the manufacturing method of the phenol resin for photoresists of this invention and the resin composition for photoresists are demonstrated.
The method for producing a phenolic resin for photoresists of the present invention (hereinafter sometimes simply referred to as “manufacturing method”)
(A) performing a condensation reaction of phenols and aldehydes under reflux conditions;
(B) raising the temperature of the reaction system after the step (a) to remove moisture and unreacted monomers;
A method for producing a phenolic resin for photoresists, comprising:
In the step (a), 0.2 mol or more of oxalic acid is used with respect to 1 mol of the phenols,
In the step (b), 0.2 mol or more of oxalic acid is used with respect to 1 mol of phenols used in the step (a).
In addition, the method for producing a phenol resin for a photoresist of the present invention is as follows.
(A) performing a condensation reaction of phenols and aldehydes under reflux conditions;
(B) raising the temperature of the reaction system after the step (a) to remove moisture and unreacted monomers;
A method for producing a phenolic resin for photoresists, comprising:
In the step (b), 0.2 mol or more of oxalic acid is used with respect to 1 mol of phenols used in the step (a).
The photoresist resin composition of the present invention is characterized by containing a photoresist resin, a photosensitive agent, and a solvent obtained by the production method of the present invention.
First, the manufacturing method of this invention is demonstrated.

In the production method of the present invention, first,
(A) A phenol and an aldehyde are subjected to a condensation reaction under reflux conditions.

  Although it does not specifically limit as phenols used with the manufacturing method of this invention, For example, Cresols, such as a phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2 , 5-xylenol, 2,6-xylenol, 3,4-xylenol, xylenols such as 3,5-xylenol, ethylphenols such as o-ethylphenol, m-ethylphenol, p-ethylphenol, isopropylphenol, In addition to alkylphenols such as butylphenol and p-tert-butylphenol, polyhydric phenols such as resorcin, catechol, hydroquinone, pyrogallol, and phloroglucin, and alkyl polyvalent phenols such as alkylresorcin, alkylcatechol, and alkylhydroquinone. Nord compounds (any alkyl group, carbon number of 1-4) can be mentioned. These can be used alone or in combination of two or more.

Among the above phenols, particularly preferred are m-cresol and p-cresol, and by using these phenols and adjusting the blending ratio of them, various properties such as sensitivity and heat resistance as a photoresist. Can be adjusted.
When m-cresol and p-cresol are used as the phenols, the ratio is not particularly limited, but the weight ratio (m-cresol / p-cresol) is preferably 9/1 to 2/8. More preferably, it is 8/2 to 4/6. When the ratio of m-cresol is less than the above lower limit value, the sensitivity may be lowered, and when it exceeds the above upper limit value, the heat resistance may be lowered.

Aldehydes used in the production method of the present invention are not particularly limited. For example, formaldehyde, paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, polyoxymethylene, chloral, hexamethylenetetramine, furfural, glyoxal, n-butyraldehyde , Caproaldehyde, allyl aldehyde, benzaldehyde, crotonaldehyde, acrolein, tetraoxymethylene, phenylacetaldehyde, o-tolualdehyde, salicylaldehyde and the like.
Among these, use of formaldehyde and paraformaldehyde is most preferable in view of characteristics.

Although it does not specifically limit as reaction molar ratio (F / P) of the said phenols (P) and aldehydes (F), It is preferable to set it as 0.5-1.0. Thereby, a phenol resin having a molecular weight preferable for use in a photoresist can be obtained.
When the reaction molar ratio exceeds the above upper limit, it may be excessively high molecular weight for use as a photoresist, or may be gelled depending on the reaction conditions. Moreover, if it is less than the said lower limit, the reduction effect of a binuclear component may become inadequate.

In the step (a), an organic solvent can be appropriately used for the reaction. Any solvent that can dissolve the phenol resin can be used. For example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol alkyl ethers such as ethylene glycol monobutyl ether, diethylene glycol dialkyl such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, and diethylene glycol dibutyl ether Propylene such as ethers, ethylene glycol alkyl ether acetates such as methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate Glycol ether ethers, ketones such as cyclohexanone and methyl amyl ketone, cyclic ethers such as dioxane, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, 2-hydroxy-2-methylpropionic acid Esters such as ethyl, ethyl ethoxyacetate, ethyl oxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, butyl acetate, methyl acetoacetate, ethyl acetoacetate And amides such as N, N′-dimethylformamide. These may be used alone or in combination of two or more.
The amount of the solvent used is not particularly limited, but if the catalyst concentration in the reaction system becomes too low, the effect of reducing the binuclear component is reduced. Therefore, the amount is preferably 20% by weight or less based on the phenols.

In the production method of the present invention, an acidic catalyst is used.
As a form using an acidic catalyst (1) In the step (a), a form using 0.2 moles or more of an acidic catalyst with respect to 1 mole of phenols,
(2) In the step (b), a form using 0.2 mol or more of an acidic catalyst with respect to 1 mol of phenols used in the step (a),
There are two types.

The above form (1) uses an acid catalyst of 0.2 mol or more per 1 mol of phenols in the step (a), that is, in the condensation reaction of phenols and aldehydes.
Since the condensation reaction in the step (a) is carried out under reflux conditions, the acidic catalyst usually used for the synthesis of the phenol resin remains as it is. For this reason, the said acidic catalyst exists in a reaction system also at the time of the start of (b) process. And by raising the temperature of the reaction system in the presence of such an excessive amount of acidic catalyst, the rearrangement reaction of the phenol resin reduces the number of low-nuclear components such as unreacted phenols and dinuclear components, Decomposition of high molecular weight components occurs. Thereby, while being able to obtain the phenol resin with little content of a binuclear component, the yield of the phenolic monomer used for reaction can be improved and the yield of a phenol resin can be improved greatly.

Moreover, the said form (2) uses an acidic catalyst 0.2 mol or more with respect to 1 mol of phenols used at the said (a) process in the (b) process.
Step (b) is a step in which after completion of the reaction in step (a), the condensed water is removed by heating, and then the monomer is removed usually under reduced pressure. As a method of using the acidic catalyst in the step (b), as in the form (1), a method of using a predetermined amount of the acidic catalyst in the step (a) and causing it to exist in the reaction system, or (a There is a method in which a condensation reaction is carried out with a small amount of an acidic catalyst that is usually used in the step), and an acidic catalyst is additionally added in the step (b).

In the method of additionally adding an acidic catalyst in the step (b), the timing of adding the acidic catalyst is not particularly limited. For example, at the start of the step (b), after the dehydration of the step (b), or ( b) can be added after the completion of the monomer removal in the step. Even if it is added at any timing, the rearrangement reaction of the phenol resin causes a decrease in low-nuclear components such as unreacted phenols and dinuclear components, and decomposition of high molecular weight components. Thereby, the phenol resin with little content of a binuclear component can be obtained.
Further, when added at the start of the step (b) or after the completion of the dehydration in the step (b), in addition to the above effect, the yield of the phenolic monomer used in the reaction is increased as in the case of the above-described form (1). And the yield of phenolic resin can be greatly improved.

  The amount of the acidic catalyst used in the above form (1) or form (2) is more preferably 0.2 to 1.0 mole relative to 1 mole of phenols. If it is less than the said lower limit, the effect of reducing a low nucleus component may not be enough. Also, even if the above upper limit is exceeded, there is no problem with the effect of reducing the low-nuclear component, but the use of an excess amount is not economical, and the efficiency when removing the acidic catalyst from the reaction system may be reduced. is there.

Although it does not specifically limit as an acidic catalyst used in the manufacturing method of this invention, For example, inorganic acids, such as hydrochloric acid, a sulfuric acid, phosphoric acid, phosphorous acid, oxalic acid, diethyl sulfuric acid, paratoluenesulfonic acid, organic phosphonic acid, etc. Examples thereof include metal salts such as organic acids and zinc acetate. These can be used alone or in combination of two or more.
Among these, it is preferable to use oxalic acid. Since oxalic acid is gasified by heating at a high temperature in the step (b), it can be easily removed from the phenol resin.
In addition, oxalic acid is less corrosive to metals than other acidic catalysts, so that corrosion of production equipment such as reactors can be suppressed, and mixing of metal components due to corrosion can be minimized. . Thereby, a phenol resin with a low content of metal impurities, which is particularly suitable for a photoresist, can be efficiently produced.
When a catalyst other than oxalic acid is used, the acidic catalyst in the phenol resin can be removed after the reaction by neutralization, water washing, or a method using an ion exchange resin or a special filter.

  Although it does not specifically limit as a weight average molecular weight of the phenol resin obtained by the manufacturing method of this invention, It is preferable that the weight average molecular weights measured by GPC are 1000-20000. More preferably, it is 1500-15000. Thereby, it can have a characteristic preferable as resin for photoresists. If the weight average molecular weight is smaller than the lower limit, heat resistance may be reduced, and if the weight average molecular weight is larger than the upper limit, the sensitivity may be insufficient.

Further, the content of the binuclear component in the photoresist resin obtained by the production method of the present invention is preferably 5% or less, particularly preferably 4% or less. When the content of the binuclear component exceeds the above upper limit, the effect of improving productivity may be reduced by reducing the sublimate.

The weight average molecular weight and the content of the binuclear component are measured by gel permeation chromatography (GPC measurement). The weight average molecular weight was calculated based on a calibration curve prepared using a polystyrene standard. The content of the binuclear component was calculated from the molecular weight distribution curve by the area ratio (%) of the binuclear component to the entire resin. GPC measurement was performed using tetrahydrofuran as an elution solvent under conditions of a flow rate of 1.0 ml / min and a column temperature of 40 ° C.
The device
・ Main body: HLC-8020 manufactured by TOSOH
-Detector: UV-8011 manufactured by TOSOH Corporation set at a wavelength of 280 nm
・ Analytical column: Showa Denko ・ SHODEX KF-802 1 、 KF-803 1 、 KF-805 1 、
It was used.

In the production method of the present invention, the reason why the content of the binuclear component that becomes a sublimate during use can be reduced is considered as follows.
In the production method of the present invention, the reaction is considered to proceed in two stages. That is, in the step (a), the reaction proceeds under the reflux condition of water in the reaction system, and bonds between monomers are formed. Next, in step (b), the reaction system after step (a) is heated to remove moisture and unreacted monomers. This temperature rise causes a rearrangement reaction of the bonds, and decomposition of high molecular weight components. And a decrease in low-nuclear components. This action is thought to result in a molecular weight distribution with dinuclear components reduced.
This rearrangement reaction hardly occurs in a temperature range (40 to 250 ° C.) for synthesizing a novolac type phenol resin when a normal amount of an acidic catalyst is used. In the present invention, the rearrangement temperature can be lowered by using a large amount of the acidic catalyst, and this effect is considered to be obtained within the reaction temperature range.
Moreover, as a form using an excess amount of the acidic catalyst, in the case of the above form (1) or in the above form (2), at the start of the step (b) or after the completion of the dehydration of the step (b) When an acidic catalyst is added, in addition to the above effects, it is also characterized by improving the yield of phenolic monomers and greatly increasing the resin yield.
Furthermore, compared with the conventional manufacturing method, a waste can be reduced and an environmental load can be reduced.

Next, a phenol resin composition for photoresist (hereinafter sometimes simply referred to as “composition”) using the phenol resin for photoresist obtained by the production method of the present invention will be described.
Although it does not specifically limit as a composition using the phenol resin for photoresists of this invention, In addition to the phenol resin for photoresists, a quinonediazide group containing compound can be contained as a photosensitizer, for example. Moreover, it is preferable to use the solvent which melt | dissolves these, melt | dissolve in this, and use with the form of a solution.

Here, as the quinonediazide group-containing compound, for example,
(1) 2,3,4-trihydroxybenzophenone, 2,4,4′-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone, 2,3,6-trihydroxybenzophenone, 2,3,4 Trihydroxy-2'-methylbenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,3', 4,4 ', 6-pentahydroxy Benzophenone, 2,2 ′, 3,4,4′-pentahydroxybenzophenone, 2,2 ′, 3,4,5-pentahydroxybenzophenone, 2,3 ′, 4,4 ′, 5 ′, 6-hexahydroxy Polyhydroxybenzophenones such as benzophenone, 2,3,3 ′, 4,4 ′, 5′-hexahydroxybenzophenone,

(2) Bis (2,4-dihydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) methane, 2- (4-hydroxyphenyl) -2- (4′-hydroxyphenyl) propane, 2- (2,4-dihydroxyphenyl) -2- (2 ′, 4′-dihydroxyphenyl) propane, 2- (2,3,4-trihydroxyphenyl) -2- (2 ′, 3 ′, 4′-tri Hydroxyphenyl) propane, 4,4 ′-{1- [4- [2- (4-hydroxyphenyl) -2-propyl] phenyl] ethylidene} bisphenol, 3,3′-dimethyl- {1- [4- [ Bis [(poly) hydroxyphenyl] alkanes such as 2- (3-methyl-4-hydroxyphenyl) -2-propyl] phenyl] ethylidene} bisphenol,

(3) Tris (4-hydroxyphenyl) methane, bis (4-hydroxy-3,5-dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -4-hydroxyphenyl Methane, bis (4-hydroxy-3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2, 5-dimethylphenyl) -3,4-dihydroxyphenylmethane, bis (4-hydroxy-3,
Tris (hydroxyphenyl) methanes such as 5-dimethylphenyl) -3,4-dihydroxyphenylmethane or methyl-substituted products thereof,

(4) Bis (3-cyclohexyl-4-hydroxyphenyl) -3-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxyphenyl) -2-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxyphenyl) -4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3-hydroxyphenylmethane Bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl-2-hydroxyphenyl) -3-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy -3-Me Ruphenyl) -4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-3-methylphenyl) -3-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-3-methylphenyl) -2-hydroxy Phenylmethane, bis (3-cyclohexyl-2-hydroxyphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl-2-hydroxyphenyl)-
2-hydroxyphenylmethane, bis (5-cyclohexyl-2-hydroxy-4-methylphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-2-hydroxy-4-methylphenyl) -4-hydroxyphenylmethane, etc. Bis (cyclohexylhydroxyphenyl) (hydroxyphenyl) methanes or methyl-substituted products thereof, and naphthoquinone-1,2-diazide-5-sulfonic acid or naphthoquinone-1,2-diazide-4-sulfonic acid, orthoanthraquinonediazide Complete ester compound, partial ester compound, amidated product or partially amidated product with quinonediazide group-containing sulfonic acid such as sulfonic acid,
And so on.

Here, the quinonediazide group-containing compound component may be contained singly or in combination of two or more. Moreover, this component is mix | blended in 5-100 weight part normally with respect to 100 weight part of said phenol resins, Preferably it is 10-50 weight part.
If the blending amount is less than the lower limit, an image faithful to the pattern cannot be obtained, and transferability may be deteriorated. On the other hand, when the above upper limit is exceeded, the sensitivity of the resist decreases.

  Examples of the solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol alkyl ethers such as ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, and diethylene glycol. Diethylene glycol dialkyl ethers such as dibutyl ether, ethylene glycol alkyl ether acetates such as methyl cellosolve acetate and ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether Propylene glycol alkyl ether acetates such as cetate, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl amyl ketone, cyclic ethers such as dioxane, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, 2- Ethyl hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl oxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, ethyl formate, ethyl acetate, acetic acid Examples include esters such as butyl, methyl acetoacetate, and ethyl acetoacetate. These may be used individually by 1 type, and may be used in mixture of 2 or more types.

  Although the usage-amount of the said solvent is not specifically limited, It is preferable that the solid content concentration of a composition shall be 30 to 65 weight%. When the solid content concentration is less than 30% by weight, the fluidity of the composition is lowered, so that it is difficult to handle and a uniform resist film is difficult to obtain by spin coating.

  In addition to the above-described components, various additives such as a surfactant, an adhesion improver, and a dissolution accelerator may be used in this composition as necessary.

  The method for preparing this composition is not particularly limited, but when no filler or pigment is added to the composition, the above components may be mixed and stirred in the usual manner, and the filler and pigment are added. In such a case, the dispersion and mixing may be performed using a dispersing device such as a dissolver, a homogenizer, or a three roll mill. Moreover, you may filter using a mesh filter, a membrane filter, etc. as needed.

  By exposing the composition thus obtained through a mask, a structural change occurs in the composition in the exposed area, and the solubility in an alkali developer is promoted. On the other hand, low solubility in an alkaline developer is maintained in the non-exposed area. A resist function is imparted by the difference in solubility generated in this way.

  Hereinafter, the present invention will be described with reference to examples. However, the present invention is not limited to these examples. In the examples and comparative examples, “parts” indicates “parts by weight” and “%” indicates “% by weight”.

1. Synthesis of phenolic resin for photoresist (1) Example 1
Phenol in which m-cresol and p-cresol were mixed in a molar ratio (m-cresol: p-cresol) = 7: 3 in a 3 L four-necked flask equipped with a stirrer, a thermometer, and a heat exchanger To 1000 parts of the product, 638 parts of 37% formalin aqueous solution (F / P = 0.85) and 420 parts of oxalic acid (0.5 mole per 1 mole of phenol) were charged and reacted under reflux for 4 hours. It was. Thereafter, dehydration is carried out under normal pressure to an internal temperature of 170 ° C., and dehydration / demonomerization is further carried out up to 200 ° C. under a reduced pressure of 70 torr. 1080 parts were obtained.

(2) Example 2
37% formalin with respect to 1000 parts of phenols in which m-cresol and p-cresol were mixed at a molar ratio (m-cresol: p-cresol) = 6: 4 in the same apparatus as in Example 1. 620 parts of an aqueous solution (F / P = 0.83) and 250 parts of oxalic acid (0.3 mol with respect to 1 mol of phenol) were charged and reacted under reflux for 4 hours. Thereafter, dehydration is carried out under normal pressure up to an internal temperature of 170 ° C., and dehydration / demonomerization is further carried out up to 200 ° C. under a reduced pressure of 70 torr. 990 parts were obtained.

(3) Example 3
In the same apparatus as in Example 1, 37% formalin with respect to 1000 parts of phenols in which m-cresol and p-cresol were mixed at a molar ratio (m-cresol: p-cresol) = 8: 2. 660 parts of an aqueous solution (F / P = 0.88) and 750 parts of oxalic acid (0.9 mol with respect to 1 mol of phenol) were charged, and the reaction was performed under reflux for 4 hours. Thereafter, dehydration is carried out under normal pressure up to an internal temperature of 170 ° C., and dehydration / demonomerization is further carried out up to 200 ° C. under a reduced pressure of 70 torr. 970 parts were obtained.

(4) Example 4
37% formalin with respect to 1000 parts of phenols in which m-cresol and p-cresol were mixed at a molar ratio (m-cresol: p-cresol) = 7: 3 in the same apparatus as in Example 1. 630 parts (F / P = 0.84) of an aqueous solution and 21 parts of oxalic acid (0.03 mol with respect to 1 mol of phenols) were charged, and the reaction was performed under reflux for 4 hours. Then, after dehydrating under normal pressure to an internal temperature of 140 ° C., 309 parts of oxalic acid (0.38 mol relative to 1 mol of phenols) was added, and the temperature was further raised to 170 ° C. Further, dehydration / demonomerization was performed to 200 ° C. under a reduced pressure of 70 torr to obtain 1060 parts of a phenol resin for photoresist having a weight average molecular weight of 3000 and a binuclear component amount of 3.8%.

(5) Example 5
37% formalin with respect to 1000 parts of phenols in which m-cresol and p-cresol were mixed at a molar ratio (m-cresol: p-cresol) = 7: 3 in the same apparatus as in Example 1. 620 parts of an aqueous solution (F / P = 0.83) and 21 parts of oxalic acid (0.03 mol with respect to 1 mol of phenol) were charged, and the reaction was performed under reflux for 4 hours. Thereafter, 479 parts of oxalic acid (0.58 mol with respect to 1 mol of phenol) was added, and the temperature was raised to an internal temperature of 170 ° C. under normal pressure. Further, dehydration / demonomerization was carried out to 200 ° C. under a reduced pressure of 70 torr to obtain 1070 parts of phenol resin for photoresist having a weight average molecular weight of 3900 and a binuclear component amount of 4.0%.

(6) Example 6
37% formalin with respect to 1000 parts of phenols in which m-cresol and p-cresol were mixed at a molar ratio (m-cresol: p-cresol) = 7: 3 in the same apparatus as in Example 1. 520 parts of an aqueous solution (F / P = 0.69) and 40 parts of oxalic acid (0.05 mol with respect to 1 mol of phenol) were charged and reacted under reflux for 4 hours. Thereafter, the internal temperature was raised to 170 ° C. under normal pressure, and dehydration / demonomerization was further performed to 200 ° C. under a reduced pressure of 70 torr. Thereafter, 50 parts of ethylene glycol monomethyl ether was added while cooling, and the internal temperature was cooled to 130 ° C. To this, 380 parts of oxalic acid (0.46 mol per 1 mol of phenol) was added, the temperature was raised again to an internal temperature of 170 ° C. under normal pressure, and dehydration / demonomer was further reduced to 200 ° C. under a reduced pressure of 70 torr. Then, 820 parts of phenol resin for photoresist having a weight average molecular weight of 4300 and a dinuclear component amount of 2.8% were obtained.

(7) Comparative Example 1
In the same apparatus as in Example 1, 37% formalin with respect to 1000 parts of phenols in which m-cresol and p-cresol were mixed at a molar ratio (m-cresol: p-cresol) = 4: 6. 450 parts of an aqueous solution (F / P = 0.60) and 21 parts of oxalic acid (0.03 mol with respect to 1 mol of phenol) were charged, and the reaction was performed under reflux for 4 hours. Thereafter, dehydration is carried out under normal pressure to an internal temperature of 170 ° C., and dehydration / demonomerization is further carried out up to 200 ° C. under a reduced pressure of 70 torr. 730 parts were obtained.

(8) Comparative Example 2
37% formalin with respect to 1000 parts of phenols in which m-cresol and p-cresol were mixed at a molar ratio (m-cresol: p-cresol) = 7: 3 in the same apparatus as in Example 1. 506 parts of an aqueous solution (F / P = 0.67) and 8 parts of oxalic acid (0.01 mol with respect to 1 mol of phenol) were charged and reacted under reflux for 4 hours. Thereafter, dehydration is carried out under normal pressure up to an internal temperature of 170 ° C., and dehydration / demonomerization is further carried out up to 200 ° C. under a reduced pressure of 70 torr. 800 parts were obtained.

  Table 1 shows the phenolic resins for photoresists obtained in Examples 1 to 6 and Comparative Examples 1 and 2.

2. Preparation of photoresist composition (1) Example 11
70 parts of the phenol resin for photoresist obtained in Example 1 and 15 parts of 2,3,4-trihydroxybenzophenone ester of naphthoquinone 1,2-diazide-5-sulfonic acid were mixed with PGMEA (propylene glycol monomethyl ether acetate). ) After dissolving in 150 parts, the solution was filtered using a membrane filter having a pore size of 1.0 μm to obtain a positive photoresist composition.

(2) Example 12
A composition was obtained in the same manner as in Example 11, except that the photoresist phenol resin obtained in Example 2 was used instead of the photoresist phenol resin obtained in Example 1.

(3) Example 13
A composition was obtained in the same manner as in Example 11, except that the photoresist phenol resin obtained in Example 3 was used instead of the photoresist phenol resin obtained in Example 1.

(4) Example 14
A composition was obtained in the same manner as in Example 11 except that instead of the phenol resin for photoresist obtained in Example 1, the phenol resin for photoresist obtained in Example 4 was used.

(5) Example 15
A composition was obtained in the same manner as in Example 11 except that instead of the phenol resin for photoresist obtained in Example 1, the phenol resin for photoresist obtained in Example 5 was used.

(6) Example 16
A composition was obtained in the same manner as in Example 11 except that instead of the phenol resin for photoresist obtained in Example 1, the phenol resin for photoresist obtained in Example 6 was used.

(7) Comparative Example 11
A composition was obtained in the same manner as in Example 11 except that the photoresist phenol resin obtained in Comparative Example 1 was used instead of the photoresist phenol resin obtained in Example 1.

(8) Comparative Example 12
A composition was obtained in the same manner as in Example 11 except that the photoresist phenol resin obtained in Comparative Example 2 was used instead of the photoresist phenol resin obtained in Example 1.

  Using the photoresist compositions obtained in Examples 11 to 16 and Comparative Examples 11 to 12, the following characteristic evaluation was performed. The results are shown in Table 2.

3. Characteristic Evaluation Method 3.1 Photoresist Phenolic Resin (1) Yield Calculated by the following formula.
Yield (%) = (weight of resin obtained / weight of charged phenolic monomer) × 100

(2) Weight average molecular weight (Mw) and content of binuclear component Measured by gel permeation chromatography (GPC measurement). The weight average molecular weight was calculated based on a calibration curve prepared using a polystyrene standard. The content of the binuclear component was calculated from the molecular weight distribution curve by the area ratio (%) of the binuclear component to the entire resin. GPC measurement was performed using tetrahydrofuran as an elution solvent under conditions of a flow rate of 1.0 ml / min and a column temperature of 40 ° C.
The device
-Body: manufactured by TOSOH-"HLC-8020"
・ Detector: TOSOH manufactured at a wavelength of 280 nm ・ “UV-8011”
・ Analytical column: Showa Denko Co., Ltd. “SHODEX KF-802 x 1, KF-803 x 1, KF-805 x 1”
It was used.

3.2 Photoresist Composition (1) Sublimation Test The photoresist composition was applied on a 3 inch silicon wafer with a spin coater to a thickness of about 1 μm and dried on a hot plate at 110 ° C. for 100 seconds. . During this drying, the silicon wafer was covered with a petri dish to collect the sublimate. This operation was performed for 10 sheets, and the weight of the substance adhering to the petri dish was measured.

(2) Film reduction rate The photoresist composition was applied to a thickness of about 1 μm on a 3-inch silicon wafer by a spin coater and dried on a hot plate at 110 ° C. for 100 seconds. The wafer was immersed in a developing solution (2.38% tetramethylammonium hydroxide aqueous solution) for 60 seconds, washed with water, and dried on a hot plate at 110 ° C. for 100 seconds. The reduction amount of the film thickness when immersed in the developer is expressed as a percentage with respect to the film thickness before being immersed in the developer, and is defined as the film reduction rate.

Examples 1 to 6 are phenolic resins for photoresist obtained by the production method of the present invention.
Examples 11 to 16 are compositions using this photoresist resin. As shown in Table 1, in each of Examples 11 to 16, the amount of sublimate was small and the film was reduced compared to Comparative Examples 11 to 12, which are compositions using the phenol resins obtained in Comparative Examples 1 and 2. The rate is also excellent. In particular, in Examples 11 to 15, in addition to the above effects, the phenol resin yield could be greatly improved. From this, it became clear that the phenol resin for photoresist obtained by the production method of the present invention is suitable for the process for the purpose of LCD production.

  The production method of the present invention can efficiently produce a phenol resin for a photoresist having a low content of a binuclear component. Therefore, the photoresist composition using the phenolic resin for photoresist obtained by the production method of the present invention can reduce contamination of the production line and improve productivity, so that semiconductors such as IC and LSI can be used. It can be suitably used for manufacturing, manufacturing of display screen devices such as LCD, and manufacturing of printing original plates.

Claims (7)

(A) performing a condensation reaction of phenols and aldehydes under reflux conditions;
(B) raising the temperature of the reaction system after the step (a) to remove moisture and unreacted monomers;
A method for producing a phenolic resin for photoresists, comprising:
In the step (a), 0.2 mol or more of oxalic acid is used with respect to 1 mol of the phenol,
In the step (b), 0.2 mol or more of oxalic acid is used with respect to 1 mol of the phenols used in the step (a). (A) performing a condensation reaction of phenols and aldehydes under reflux conditions;
(B) raising the temperature of the reaction system after the step (a) to remove moisture and unreacted monomers;
A method for producing a phenolic resin for photoresists, comprising:
In the step (b), 0.2 mol or more of oxalic acid is used with respect to 1 mol of the phenols used in the step (a). The phenols, m- cresol and consists of a p- cresol, and the weight ratio (m-cresol / p- cresol) is, for photoresist of claim 1 or 2 which is 9 / 1-2 / 8 A method for producing a phenolic resin. The phenol (P) with an aldehyde (F) and the reaction molar ratio (F / P) is, for photoresists phenolic resin according to any one of claims 1 0.5 to 1.0 3 Production method. The aldehydes, manufacturing method of a photoresist phenolic resin according to any one of claims 1 to 4 is formaldehyde. The method for producing a phenol resin for a photoresist according to any one of claims 1 to 5 , wherein the obtained phenol resin has the following characteristics.
(I) The content of the binuclear component is 5% or less of the entire resin.
(II) The weight average molecular weight measured by GPC is 1000-20000. It claims 1 to photoresist resin obtained by the production method according to any one of 6, photosensitizer, and, a photoresist resin composition characterized by containing a solvent.