KR20120029326A - Novolac type phenolic resin and resin composition for photoresist - Google Patents

Abstract

PURPOSE: A novolac phenolic resin and a resin composition for photoresist containing the same are provided to improve the heat resistance characteristic, the sensitivity, and the residual film rate of the resin. CONSTITUTION: A novolac phenolic resin is obtained from the reaction of phenols, dihydroxybenzene or the derivative of the same, and formaldehyde under an acid catalyst. The phenols contains 50-90 weight% of metacresol and 10-50 weight% of paracresol. The weight average molecular weight of polystyrene conversion by gel permeation chromatography with respect to the novolac phenolic resin is between 15000 and 45000. The dihydroxybenzene or the derivative of the same is one or more selected from resorcinol, catechol, and hydroquinone. The weight ratio of the dihydroxybenzene or the derivative of the same with respect to the phenols is between 1 and 10 weight%. The molar ratio of the formaldehyde with respect to the phenols is between 0.4 and 1.0.

Description

Novolak-type phenolic resin and resin composition for photoresist {NOVOLAC TYPE PHENOLIC RESIN AND RESIN COMPOSITION FOR PHOTORESIST}

The present invention relates to a resin composition for novolac type phenol resin and photoresist.

A fine circuit pattern, such as a liquid crystal display device circuit or a semiconductor integrated circuit, may uniformly coat or apply a photoresist composition to an insulating film or a conductive metal film formed on a substrate, and apply the photoresist composition coated in the presence of a mask having a predetermined shape. It exposes and develops and is manufactured in the pattern of the target shape. Thereafter, the metal film or the insulating film is removed using the patterned photoresist film as a mask, and then the remaining photoresist film is removed to form a fine circuit on the substrate. Such a photoresist composition is classified into a negative type and a positive type depending on whether the exposed portion or the exposed photoresist film is soluble or insoluble.

Generally, the photosensitive agent which has quinonediazide groups, such as a naphthoquinone diazide compound, and alkali-soluble resin (for example, novolak-type phenol resin) are used for a positive type photoresist composition. The positive photoresist composition composed of such a composition exhibits high resolution by developing with an alkaline solution after exposure, and is used for manufacturing semiconductors such as IC and LSI, manufacturing liquid crystal display devices such as LCDs, and manufacturing printing originals. It is becoming. Moreover, novolak-type phenol resin has high heat resistance resulting from the structure which has many aromatic rings with respect to plasma dry etching, and many positive types containing a novolak-type phenol resin and a naphthoquinone diazide type photosensitive agent so far are Photoresists have been developed and put into practical use and have achieved great results.

Important characteristics in practical use of the photoresist composition for liquid crystal display circuits are the sensitivity, development contrast, resolution, adhesion to the substrate, residual film ratio, heat resistance, and circuit uniformity of the formed resist film. Especially, application of monomers, such as alkylphenols and aromatic aldehyde, is examined for high heat resistance. However, although all showed some improvement in heat resistance, no significant effect was obtained. In addition, due to the evolution of the photoresist process technology, heat resistance at a high temperature is required more than ever. Patent Document 1 discloses the use of a method of treating a novolak resin in order to improve photoresist properties, and the above contents are widely known to those skilled in the art. However, by classifying, the sensitivity of the resist film, which is one of the important characteristics of the photoresist, is lowered. As a result, the process time is lengthened, resulting in insufficient mass productivity. Moreover, heat resistance can be improved by using the high softening point novolak resin obtained by increasing the molecular weight of a resist film composition. In this case, however, the sensitivity of the resist film is lowered due to the higher molecular weight of the resist film composition.

Japanese Patent Publication No. 2002-508415 Japanese Unexamined Patent Publication No. Hei 6-59445

This invention provides the novolak-type phenol resin which can be used for the resin composition for photoresists which has the outstanding heat resistance and favorable sensitivity, and the resin composition for photoresists using this.

The novolak-type phenol resin of the 1st aspect of this invention is a novolak-type phenol resin obtained by making phenol, dihydroxybenzene, or its derivative (s) react with formaldehyde under an acidic catalyst, and the composition of a phenol is metacresol 50? 90 weight%, paracresol 10? It is 50 weight%, and the weight average molecular weight of polystyrene conversion by GPC is 15000? It is a novolak-type phenol resin characterized by being 45000.

In the novolak-type phenol resin, the dihydroxybenzene or its derivatives may be one or two or more selected from resorcinol, catechol and hydroquinone.

In said novolak-type phenol resin, the weight ratio of the said dihydroxy benzene or its derivative with respect to the said phenol is 1? 10 weight% may be sufficient.

In the novolak type phenol resin, the molar ratio of the formaldehyde to the phenols is 0.4? 1.0 may be sufficient.

The said novolak-type phenol resin may be used for a photoresist.

The resin composition for photoresist of the 2nd aspect of this invention contains the novolak-type phenol resin, the photosensitive agent, and the solvent of the 1st aspect of this invention, It is a resin composition for photoresists.

According to this invention, the novolak-type phenol resin which can be used for the resin composition for photoresists excellent in heat resistance, a sensitivity, and a residual film rate, and the resin composition for photoresists using this can be obtained.

EMBODIMENT OF THE INVENTION Below, the novolak-type phenol resin and resin composition for photoresists of this invention are demonstrated in detail.

The novolak-type phenol resin of the present invention is a novolak-type phenol resin obtained by reacting phenols, dihydroxybenzene or derivatives thereof, and formaldehyde under an acidic catalyst, and the composition of the phenols is metacresol 50? 90 weight%, paracresol 10? It is 50 weight%, and the weight average molecular weight of polystyrene conversion by GPC is 15000? It is characterized in that 45000.

Phenols used for manufacture of the novolak-type phenol resin of this invention are metacresol and paracresol, and metacresol 50? 90 weight%, paracresol 10? It consists of 50 weight%. Preferably, metacresol 55? 75 wt%, Paracresol 25? 45 wt%. By using methacresol and paracresol as said phenols in the said ratio, it can be set as the novolak-type phenol resin which has an alkali dissolution time (ADR) especially suitable for a photoresist, and the heat resistance of a photoresist can be improved.

As dihydroxybenzene or its derivative used for manufacture of the novolak-type phenol resin of this invention, resorcinol, catechol, hydroquinone, 2-methylresorcinol, 4-methylresorcinol, 4-ethyl Resorcinol and the like can be exemplified. By using dihydroxy benzene or its derivative, alkali solubility after exposure of the composition for photoresists using the novolak-type phenol resin obtained can be improved, and the sensitivity of a photoresist can be improved.

As dihydroxybenzene or its derivative, it is preferable to use what is chosen from resorcinol, catechol, and hydroquinone among these. Thereby, a sensitivity and heat resistance can be made compatible.

The dihydroxy benzene or its derivative is 1 to 1 to phenols. It is preferable to use 10 weight%. More preferably 1? 5 wt%.

Thereby, the novolak-type phenol resin which has alkali dissolution time (ADR) suitable especially for a photoresist can be obtained, and the heat resistance of a photoresist can be improved. When the dihydroxybenzene content ratio increases, alkali solubility becomes too high, and the remaining film ratio (film reduction of unexposed portions), which is another important characteristic, becomes worse.

The novolac phenol resin of the present invention has a high molecular weight and a high softening point. By raising a softening point, the heat resistance of a photoresist can be improved.

Formaldehyde is used in the production of the novolac phenolic resin of the present invention. By using formaldehyde alone as aldehydes, it is possible to obtain a novolak-type phenol resin excellent in alkali dissolution rate even if the molecular weight is increased.

In the present invention, the molar ratio of formaldehyde to the phenols is 0.4? 1.0 is preferable, More preferably, it is 0.5? 0.9.

By setting it as said molar ratio, the novolak-type phenol resin which has a weight average molecular weight especially suitable for photoresists can be obtained.

The weight average molecular weight (dalton) of polystyrene conversion by GPC of the novolak-type phenol resin of this invention is 15000? 45000, preferably 20000? 40000, more preferably 21000? 39000. By setting it as said weight average molecular weight, the novolak-type phenol resin which is especially excellent in the balance of heat resistance and a sensitivity can be obtained. If the weight average molecular weight is low, the heat resistance is poor, and if it is too high, the sensitivity is slow.

In addition, the said weight average molecular weight can be calculated based on the analytical curve prepared using the polystyrene standard material by the gel permeation chromatography (GPC) measurement. GPC measurement can be performed on tetrahydrofuran as an elution solvent on the conditions of 1.0 mL / min of flow volume, and 40 degreeC of column temperature.

The device,

? Main body: manufactured by TOSOH, Inc. `` HLC-8020 ''

? Detector: The product made by TOSOH set to wavelength 280nm? "UV-8011"

? Analytical column: SHOWEX KF-802, KF-803, KF-805 can be used.

As an acidic catalyst at the time of reaction of a phenol, dihydroxy benzene, or its derivatives, and aldehydes, For example, inorganic acids, such as hydrochloric acid, a sulfuric acid, phosphoric acid, a boric acid, organic acids, such as oxalic acid, an acetic acid, paratoluenesulfonic acid, are mentioned, for example. These can be mentioned, These can be used individually and in mixture. Moreover, the use of what can be easily removed from a reaction system by decomposition, sublimation, etc. at the time of monomer removal is preferable. The amount used depends on the type of catalyst, but the pH in the reaction system is 1? It is preferable to set the quantity which becomes the range of 6.

The manufacturing method of the novolak-type phenol resin of this invention is demonstrated below according to the reaction sequence.

In the reaction, phenols, dihydroxybenzenes or derivatives thereof, and acidic catalysts are injected into a reaction apparatus including a stirrer, a thermometer, and a heat exchanger, and the temperature is raised to a predetermined temperature. After reaching the predetermined temperature, successive addition of formaldehyde is started. Although the sequential addition temperature and time can be set suitably according to the reactivity of a monomer and the target characteristic, it can be set to the level which can be manufactured stably and economically.

The addition time of formaldehyde is 30? 300 minutes is preferable, More preferably, it is 60? 180 minutes. By setting it as the said addition time, reaction can be advanced at an appropriate speed | rate without a rapid temperature rise.

Moreover, the addition temperature of formaldehyde is 70? 130 degreeC is preferable, More preferably, it is 90? 110 ° C. By setting it as the said sequential addition temperature, reaction can be advanced at a suitable speed | rate without a rapid temperature rise.

After completion of the sequential addition, the reaction can be continued as needed. Moreover, at the time of sequential addition and reaction, you may add and use a reaction solvent as needed, Although the kind of solvent is not specifically limited, It can be used if it is a solvent in which a phenol resin is dissolved.

As an example, ketones, such as methyl ethyl ketone and methyl isobutyl ketone, alcohols, such as butanol, and ether alcohols, such as ethoxy ethanol, are mentioned.

After completion | finish of the said reaction, in order to remove the added acidic catalyst, water is added and water washing is performed as needed. The amount and the number of washings are not particularly limited, but the number of washings is 1? About 5 times is especially preferable from a residual catalyst amount and an economic point of view. In addition, the water washing temperature is not particularly limited, but from the viewpoint of efficiency and workability of catalyst species removal is 40? It is preferable to carry out at 95 degreeC. In the case of washing with water, when the separation between the resin and the washing water is poor, it is effective to add a solvent that lowers the viscosity of the resin and to increase the washing temperature. Although this solvent is not specifically limited, It can use if it melt | dissolves a phenol resin and lowers a viscosity.

As an example, ketones, such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, alcohols, such as methanol, ethanol, butanol, and ether alcohols, such as ethoxy ethanol, are mentioned.

After completion of the washing with water, dehydration and demonomerization can be performed under normal pressure and reduced pressure to obtain a novolac phenol resin. Although the conditions of dehydration and a demonomer are not limited, When the stability (deviation) and the viscosity of the obtained novolak-type phenol resin are considered, the degree of pressure reduction is 0.1? It is especially preferable to carry out at about 200 Torr, and the extraction temperature from the reaction apparatus is 150? It is more preferable to carry out at 250 degreeC.

The novolak-type phenol resin of this invention can be used suitably for photoresists.

The novolak-type phenol resin of this invention uses metacresol and paracresol as predetermined | prescribed phenols. Thereby, it can be set as resin which has the alkali dissolution time (ADR) especially suitable for a photoresist. The weight average molecular weight of resin is made high for the purpose of improving the heat resistance of a photoresist. Usually, when the weight average molecular weight is too high, the alkali dissolution time (ADR) is slowed down (resist sensitivity is deteriorated) and these defects can be compensated for by using dihydroxybenzene or its derivative together with phenols. By introducing dihydroxybenzene or its derivatives, many hydroxyl groups can be introduced into the resin, and the solubility in the developing solution after exposure is increased, so that a resin having an alkali dissolution time (ADR) suitable for a photoresist can be obtained.

When such a novolak-type phenol resin is used, the resin composition for photoresists which has high sensitivity, high heat resistance, and high residual film ratio can be obtained.

Next, the resin composition for photoresists (hereinafter may be simply referred to as "composition") of the present invention will be described.

The composition of this invention contains the novolak-type phenol resin, the photosensitizer, and the solvent of the said invention, It is characterized by the above-mentioned.

Although it does not specifically limit as said photosensitive agent, For example,

(1) 2,3,4-trihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone, 2,3,6-trihydroxybenzo Phenone, 2,3,4-trihydroxy-2'-methylbenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,3 ', 4,4', 6-pentahydroxybenzophenone, 2,2 ', 3,4,4'-pentahydroxybenzophenone, 2,2', 3,4,5-pentahydroxy Polyhydroxybenzoates such as benzophenone, 2,3 ', 4,4', 5 ', 6-hexahydroxybenzophenone, and 2,3,3', 4,4 ', 5'-hexahydroxybenzophenone Penon,

(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'-trihydroxyphenyl) propane, 4,4 '-{1- [4- [2- (4-hydroxyphenyl) -2-propyl] phenyl] ethylidene} bisphenol, 3 Bis [(poly) hydroxyphenyl] alkanes such as 3'-dimethyl- {1- [4- [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-hydroxyphenylmethane, 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-3,5-dimethylphenyl) -3,4-dihydroxyphenylmethane Tris (hydroxyphenyl) methanes such as methyl substituents thereof,

(4) bis (3-cyclohexyl-4-hydroxyphenyl) -3-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxyphenyl) -2-hydroxyphenylmethane, bis (3-cyclo Hexyl-4-hydroxyphenyl) -4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy 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-methylphenyl) -4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-3-methylphenyl)- 3-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-3-methylphenyl) -2-hydroxyphenylmethane, bis (3-cyclohexyl-2-hydroxyphenyl) -4-hydroxyphenyl Methane, bis (3-cyclohexyl-2-hydroxyphenyl) -2 -Hydroxyphenylmethane, bis (5-cyclohexyl-2-hydroxy-4-methylphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-2-hydroxy-4-methylphenyl) -4-hydroxy Bis (cyclohexyl hydroxyphenyl) (hydroxyphenyl) methane, such as oxyphenylmethane, or a methyl substituent, etc. Naphthoquinone-1,2-diazide-5-sulfonic acid or naphthoquinone-1,2-dia Complete ester compounds, partial ester compounds, amidates or partial amidates of quinonediazide group-containing sulfonic acids such as zide-4-sulfonic acid and orthoanthraquinonediazidesulfonic acid can be preferably used.

As said solvent, ethylene glycol alkyl ethers, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol di, for example Diethylene glycol dialkyl ethers such as ethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, ethylene glycol alkyl ether acetates such as methyl cellosolve acetate, and ethyl cellosolve acetate, and propylene glycol monomethyl Propylene glycol alkyl ether acetates such as ether acetate, propylene glycol monoethyl ether acetate and propylene glycol monopropyl ether acetate, ketones such as acetone, methyl ethyl ketone, cyclohexanone and methyl amyl ketone, and cyclic ethers such as dioxane And 2-hydroxypropion Methyl acid, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl oxyacetate, methyl 2-hydroxy-3-methylbutyrate, 3-methoxybutyl acetate, 3 Esters such as -methyl-3-methoxybutyl acetate, ethyl formate, ethyl acetate, butyl acetate, methyl acetoacetate and ethyl acetoacetate. These may be used individually by 1 type and may mix and use 2 or more types.

Although content of the said solvent is not specifically limited, The solid content concentration of a composition is 30 to the whole. It is preferable to set it as 65 weight%. More preferably 50? 65 wt%. By making solid content concentration into the said range, the fluidity | liquidity of a composition can be made favorable and a uniform resist film can be obtained.

Moreover, in addition to the component demonstrated above, you may use various additives, such as surfactant, an adhesion improving agent, a dissolution promoter, for the composition of this invention as needed.

Although it does not specifically limit as a preparation method of the composition of this invention, When not adding a filler and a pigment to a composition, only the mixing and stirring of the said component by a conventional method may be sufficient, and when adding a filler and a pigment, For example, what is necessary is just to disperse | distribute and mix using dispersing apparatuses, such as a resolver, a homogenizer, and three roll mills. Moreover, you may filter using a mesh filter, a membrane filter, etc. further as needed.

By exposing through the mask to the composition of this invention obtained in this way, a structural change arises in a composition in an exposure part, and the solubility to alkaline developing solution can be promoted. On the other hand, in the non-exposed part, since the low solubility with respect to alkaline developing solution is maintained, the resist function can be provided by the difference in the solubility which generate | occur | produced in this way.

In the resin composition for photoresists using the novolak-type phenol resin of the present invention, it is considered that high molecular weight of the novolak resin is important for improving heat resistance. To compensate for the decrease in sensitivity due to high molecular weight, dihydroxybenzene or its derivatives exert an effect.

Example

Hereinafter, an Example demonstrates this invention. However, the present invention is not limited by these examples. In addition, "part" described in an Example and a comparative example shows a "weight part" and "%" represents the "weight%." In addition, content of a free monomer is computed from the area ratio by GPC measurement.

1. Synthesis of Novolac Phenolic Resin

Example 1

700 parts of metacresol, 300 parts of paracresol, 30 parts of resorcinol and 5 parts of oxalic acid were injected | poured to the 3-liter four-necked flask equipped with the stirrer, the thermometer, and the heat exchanger, Raised to 103 ° C. After reaching | attaining temperature, 480 parts of 37% formalin (injection molar ratio A / C = 0.650 with respect to all phenols) of 97% of internal temperature was 97? The mixture was added for 3 hours while maintaining at 103 캜, and then refluxed for 2 hours, followed by dehydration under normal pressure, elevated to 150 캜 internal temperature, and then dehydration and demonomer to 200 캜 under reduced pressure of 70 Torr. It carried out and obtained 700 parts of novolak-type phenol resins (A). The weight average molecular weight of obtained resin was 21000 and 2.3% of free monomers.

Example 2

700 parts of metacresol, 300 parts of paracresol, 30 parts of resorcinol and 5 parts of oxalic acid were injected | poured to the 3-liter four-necked flask equipped with the stirrer, the thermometer, and the heat exchanger, Raised to 103 ° C. After reaching | attaining temperature, 560 parts of formalin 37% (injection molar ratio A / C = 0.750 with respect to all the phenols) of 97% of internal temperature 97? The mixture was added for 3 hours while maintaining at 103 캜, and then refluxed for 2 hours, followed by dehydration under normal pressure, elevated to 150 캜 internal temperature, and then dehydration and demonomer to 200 캜 under reduced pressure of 70 Torr. It carried out and obtained 720 parts of novolak-type phenol resins (B). The weight average molecular weight of obtained resin was 30000 and free monomer 2.1%.

Example 3

700 parts of metacresol, 300 parts of paracresol, 30 parts of resorcinol and 5 parts of oxalic acid were injected | poured to the 3-liter four-necked flask equipped with the stirrer, the thermometer, and the heat exchanger, Raised to 103 ° C. After reaching | attaining temperature, 640 parts of 37% formalin (injection molar ratio A / C = 0.850 with respect to all the phenols) of 97% were obtained. The mixture was added for 3 hours while maintaining at 103 캜, and then refluxed for 2 hours, followed by dehydration under normal pressure, elevated to 150 캜 internal temperature, and then dehydration and demonomer to 200 캜 under reduced pressure of 70 Torr. It carried out and obtained 750 parts of novolak-type phenol resins (C). The weight average molecular weight of obtained resin was 40000 and free monomer 1.8%.

Example 4

700 parts of methacresol, 300 parts of paracresol, 50 parts of resorcinol and 5 parts of oxalic acid were poured into a 3-liter four-necked flask equipped with a stirrer, a thermometer and a heat exchanger. Raised to 103 ° C. After reaching | attaining temperature, 620 parts of 37% formalin (injection molar ratio A / C = 0.830 with respect to all phenols) were 97 degreeC in internal temperature. The mixture was added for 3 hours while maintaining at 103 캜, and then refluxed for 2 hours, followed by dehydration under normal pressure, elevated to 150 캜 internal temperature, and then dehydration and demonomer to 200 캜 under reduced pressure of 70 Torr. It carried out and obtained 750 parts of novolak-type phenol resins (D). The weight average molecular weight of obtained resin was 40000 and free monomer 2.0%.

Comparative Example 1

Into a 3-liter four-necked flask equipped with a stirrer, a thermometer, and a heat exchanger, 600 parts of metacresol and 400 parts of paracresol were injected, followed by 97? Raised to 103 ° C. After reaching the temperature, 500 parts of 37% formalin (injection molar ratio A / C = 0.675 to all phenols) was obtained at 97? The mixture was added for 3 hours while maintaining at 103 캜, and then refluxed for 2 hours, followed by dehydration under normal pressure, elevated to 150 캜 internal temperature, and then dehydration and demonomer to 200 캜 under reduced pressure of 70 Torr. It carried out and obtained 700 parts of novolak-type phenol resins (E). The weight average molecular weight of obtained resin was 20000 and free monomer 2.4%.

Comparative Example 2

Into a 3-liter four-necked flask equipped with a stirrer, a thermometer, and a heat exchanger, 600 parts of metacresol and 400 parts of paracresol were injected, followed by 97? Raised to 103 ° C. After reaching | attaining temperature, 580 parts of formalin 37% (injection molar ratio A / C = 0.775 with respect to all phenols) were 97 degreeC in internal temperature. The mixture was added for 3 hours while maintaining at 103 캜, and then refluxed for 2 hours, followed by dehydration under normal pressure, elevated to 150 캜 internal temperature, and then dehydration and demonomer to 200 캜 under reduced pressure of 70 Torr. It carried out and obtained 720 parts of novolak-type phenol resins (F). The weight average molecular weight of obtained resin was 30000 and free monomer 2.2%.

Comparative Example 3

Into a 3-liter four-necked flask equipped with a stirrer, a thermometer, and a heat exchanger, 600 parts of metacresol and 400 parts of paracresol were injected, followed by 97? Raised to 103 ° C. After reaching | attaining temperature, 660 parts of 37% formalin (injection molar ratio A / C = 0.875 with respect to all phenols) of 97% of internal temperature was carried out. The mixture was added for 3 hours while maintaining at 103 캜, and then refluxed for 2 hours, followed by dehydration under normal pressure, elevated to 150 캜 internal temperature, and then dehydration and demonomer to 200 캜 under reduced pressure of 70 Torr. It carried out and obtained 740 parts of novolak-type phenol resins (G). The weight average molecular weight of obtained resin was 40000 and free monomer 2.0%.

Comparative Example 4

400 parts of metacresol and 600 parts of paracresol were injected into a 3-liter four-necked flask equipped with a stirrer, a thermometer, and a heat exchanger. Raised to 103 ° C. After reaching | attaining temperature, 500 parts of 37% formalin (injection molar ratio A / C = 0.600 with respect to all the phenols) of 97% were obtained. The mixture was added for 3 hours while maintaining at 103 캜, and then refluxed for 2 hours, followed by dehydration under normal pressure, elevated to 150 캜 internal temperature, and then dehydration and demonomer to 200 캜 under reduced pressure of 70 Torr. It carried out and obtained 650 parts of novolak-type phenol resins (H). The weight average molecular weight of obtained resin was 21000 and 2.0% of free monomers.

In addition, the weight average molecular weight of a novolak-type phenol resin is computed based on the analytical curve created using the polystyrene standard substance by the gel permeation chromatography (GPC) measurement. GPC measurement was performed on tetrahydrofuran as an elution solvent on the conditions of 1.0 mL / min of flow volume, and the column temperature of 40 degreeC.

The device,

? Main body: manufactured by TOSOH, Inc. `` HLC-8020 ''

? Detector: The product made by TOSOH set to wavelength 280nm? "UV-8011"

? Analytical column: Showa Denko manufactured "SHODEX KF-802, KF-803, KF-805", respectively.

2. Preparation of resin composition for photoresist

(1) Example 5

70 parts of phenol resin A for photoresist obtained in Example 1 and 15 parts of 2,3,4-trihydroxybenzophenone ester of naphthoquinone 1,2-diazide-5-sulfonic acid were prepared using propylene glycol monomethyl ether acetate ( After dissolving in 150 parts of PGMEA, it filtered using the membrane filter of 1.0 micrometer of pore diameters, and prepared the resin composition for positive photoresists.

(2) Example 6

A composition was prepared in the same manner as in Example 5 except that the phenol resin B for photoresist obtained in Example 2 was used instead of the phenol resin A for photoresist.

(3) Example 7

A composition was prepared in the same manner as in Example 5 except that the phenol resin C for photoresist obtained in Example 3 was used instead of the phenol resin A for photoresist.

(4) Example 8

A composition was prepared in the same manner as in Example 5 except that the phenol resin D for photoresist obtained in Example 4 was used instead of the phenol resin A for photoresist.

(5) Comparative Example 5

70 parts of phenol resin E for photoresist obtained in Comparative Example 1 and 15 parts of 2,3,4-trihydroxybenzophenone ester of naphthoquinone 1,2-diazide-5-sulfonic acid were dissolved in 150 parts of PGMEA. It filtered using the membrane filter of 1.0 micrometer of pore diameters, and prepared the resin composition for positive photoresists.

(6) Comparative Example 6

A composition was prepared in the same manner as in Comparative Example 5 except that instead of the phenol resin E for photoresist, the phenol resin F for photoresist obtained in Comparative Example 2 was used.

(7) Comparative Example 7

A composition was prepared in the same manner as in Comparative Example 5 except that the phenol resin G for photoresist obtained in Comparative Example 3 was used instead of the phenol resin E for photoresist.

(7) Comparative Example 8

A composition was prepared in the same manner as in Comparative Example 5 except that phenol resin H for photoresist obtained in Comparative Example 4 was used instead of phenol resin E for photoresist.

Example 5 8, and comparative example 5? The characteristic evaluation shown below was performed using the photoresist resin composition obtained in step 8. The results are shown in Table 1.

3. Evaluation method of characteristics

(1) Evaluation method of heat resistance

The resin composition for photoresist was apply | coated so that the film thickness at the time of drying may be 1.5 micrometers with a spin coater on the hexamethyldisilazane treated silicon wafer, and it dried at 110 degreeC for 90 second on a hotplate. Then, it exposed through the test chart mask using the reduced-projection exposure apparatus, and developed for 50 second using the developing solution (2.38% tetramethylammonium hydroxide aqueous solution). The obtained silicon wafer was left to stand on the hotplate which changed temperature for 30 minutes, and the shape of the resist pattern on a silicon wafer was observed with the scanning electron microscope, and the temperature at which a normal resist pattern was no longer obtained was made into heat resistant temperature.

(2) measuring method of sensitivity

The resin composition for photoresist was applied to a 3-inch silicon wafer with a spin coater so as to have a thickness of about 1 μm, and dried on a 110 ° C. hot plate for 100 seconds. Subsequently, a test chart mask was superimposed on this silicon wafer and irradiated with ultraviolet rays of 20 mJ / cm 2, 40 mJ / cm 2 and 60 mJ / cm 2, respectively, and developed for 90 seconds using a developer (2.38% aqueous tetramethylammonium hydroxide solution). It was. The following references | standards evaluated the obtained pattern by observing a pattern shape with a scanning electron microscope.

An image can be formed at less than A 20 mJ / cm 2.

B 20? Images can be formed at 40 mJ / cm 2.

C 40? Images can be formed at 60 mJ / cm 2.

From the results in Table 1, Example 5? 8 is a composition for photoresists using the novolak-type phenol resin of the present invention, Comparative Example 4? It was confirmed that the heat resistance was excellent while maintaining the sensitivity and the residual film ratio as compared to 6. The novolak-type phenolic resin of the present invention has a high molecular weight, has a high softening point of the resin, can improve the heat resistance of the resist, and is highly sensitive because it contains many hydroxyl groups derived from dihydroxybenzene or its derivatives. It is thought that the novolak-type phenol resin which enables manufacture of the photoresist which combines heat resistance, high sensitivity, and a high residual film rate is considered.

Since the resin composition for photoresists of this invention using the novolak-type phenol resin of this invention has favorable thermal stability and is highly sensitive, it can be used suitably for manufacture of the microcircuits of a liquid crystal display device circuit and a semiconductor integrated circuit.

Claims (13)

As a novolak-type phenol resin obtained by making phenols, dihydroxybenzene or its derivative (s) react with formaldehyde under an acidic catalyst,
The composition of phenols is metacresol 50? 90 weight%, paracresol 10? It is 50 weight%, and the weight average molecular weight of polystyrene conversion by GPC is 15000? A novolak-type phenol resin characterized by being 45000. The method of claim 1,
The novolak-type phenol resin of the said dihydroxy benzene or its derivative (s) is 1 type (s) or 2 or more types chosen from resorcinol, catechol, and hydroquinone. The method according to claim 1 or 2,
The weight ratio of the dihydroxybenzene or its derivative to the phenols is 1? Novolak-type phenol resin which is 10 weight%. The method according to claim 1 or 2,
The molar ratio of the formaldehyde to the phenols is 0.4? 1.0 phosphorus novolak type phenolic resin. The method of claim 3, wherein
The molar ratio of the formaldehyde to the phenols is 0.4? 1.0 phosphorus novolak type phenolic resin. The method according to claim 1 or 2,
The novolak type phenol resin used for a photoresist. The method of claim 3, wherein
The novolak type phenol resin used for a photoresist. The method of claim 4, wherein
The novolak type phenol resin used for a photoresist. The method of claim 5, wherein
The novolak type phenol resin used for a photoresist. The novolak-type phenol resin, the photosensitive agent, and the solvent of Claim 1 or 2 are contained, The resin composition for photoresists characterized by the above-mentioned. The resin composition for photoresists containing the novolak-type phenol resin of Claim 3, the photosensitive agent, and a solvent. The resin composition for photoresists containing the novolak-type phenol resin of Claim 4, the photosensitive agent, and a solvent. The novolak-type phenol resin, the photosensitive agent, and the solvent of Claim 5 are contained, The resin composition for photoresists characterized by the above-mentioned.