TW201339214A - Resin composition for photoresist - Google Patents

Abstract

The resin composition for photoresist according to the present invention is characterized by adopting the following novolac varnish type phenolic resin as an additive to promote photosensitivity of the photoresist. The novolac varnish type phenolic resin is characterized by solely using o-cresol or combining cresol as phenol and having a weight average molecular weight of 200 to 500 as measured by GPC.

Description

Resin composition for photoresist

The present invention relates to a resin composition for a photoresist.

The fine circuit pattern used in the liquid crystal display device circuit or the semiconductor integrated circuit is produced by uniformly coating or coating a photoresist composition on an insulating film or a conductive metal film formed on a substrate. The photoresist composition is exposed and developed in the presence of a mask of a specific shape to obtain a photoresist film formed with a pattern of a target shape, and thereafter, the patterned photoresist film is used as a mask (mask) ) to remove the conductive metal film or insulating film, and then remove the residual photoresist film. Such a photoresist composition is classified into a negative shape and a positive shape depending on whether a portion to be exposed or a portion of the exposed photoresist film is soluble or insoluble in the developer.

The positive-type photoresist composition generally contains a sensitizing agent having a quinonediazide group such as a naphthoquinone diazide compound and an alkali-soluble resin (for example, a novolac type phenol resin). Such a positive-type photoresist composition exhibits high resolution in exposure and development processing using an alkaline solution, and therefore can be used for IC (Integrated Circuit), LSI (Large Scale Integration) Semiconductor manufacturing such as circuit), manufacture of liquid crystal display screen devices such as LCD (Liquid Crystal Display), and manufacture of printing original plates. Further, the novolac type phenol resin has high heat resistance due to a structure having a large number of aromatic rings for plasma dry etching. Therefore, a variety of novolak-type phenol resins have been developed so far. A positive type resist of a naphthoquinone diazide sensitizer is practical and can be cited as a large result.

The practical characteristics of the photoresist composition for the liquid crystal display device circuit are the sensitivity, development contrast, resolution, adhesion to the substrate, residual film ratio, heat resistance, and uniform circuit line width of the formed photoresist film. Degree (CD (Critical Dimension) uniformity, critical dimension uniformity). Among them, in order to achieve high heat resistance, studies on the application of monomers such as alkylphenols or aromatic aldehydes are being carried out. However, although a little progress has been made, no dramatic effect has been obtained. Further, due to the evolution of the photoresist forming technique, heat resistance at a high temperature is further required as compared with the prior art. Patent Document 1 discloses a method of fractionating a novolac type phenol resin in order to improve the properties of the photoresist. The fractionation treatment is widely known in the art, but the sensitivity of the important characteristics as a photoresist due to fractional distillation is low and the step time is long, so that mass production is lacking.

[Patent Document 1] Japanese Patent Publication No. 2002-508415

[Patent Document 2] Japanese Patent Laid-Open No. Hei 6-59445

An object of the present invention is to provide a resin composition for a photoresist having high heat resistance, residual film ratio and sensitivity.

This object is achieved by the present invention [1] described below.

[1] A resin composition for a photoresist comprising: (A) 100 parts by weight of a novolak type phenol resin containing no o-cresol component; (B) 1 to 10 parts by weight of a novolac type phenol resin, by the adjacent The phenol of 30 to 100% by weight of phenol and 0 to 70% by weight of p-cresol are reacted with formaldehyde in the presence of an acidic catalyst, and the weight average molecular weight measured by GPC is 200 or more and less than 500; (C) sensitizer; and (D) solvent.

According to the present invention, the sensitivity of the photoresist can be improved without lowering various physical properties such as heat resistance and residual film ratio.

Hereinafter, the resin composition for a photoresist of the present invention will be described in detail.

The resin composition for a photoresist of the present invention contains: (A) 100 parts by weight of a novolak type phenol resin containing no o-cresol component; (B) 1 to 10 parts by weight of a novolak type phenol resin, and an ortho-cresol 30 ～100% by weight, 0 to 70% by weight of p-cresol and phenol are obtained by reacting with formaldehyde in the presence of an acidic catalyst, and the weight average molecular weight measured by GPC is 200 or more and less than 500; a sensitizer; and (D) a solvent.

Hereinafter, the novolac type phenol resin (A) containing no o-cresol component used in the present invention will be described.

The novolac type phenol resin (A) which does not contain an o-cresol component used in the present invention means that the monomer component constituting the novolac type phenol resin is a novolac-free novolac phenol resin.

The novolac type phenol resin (A) which does not contain an o-cresol component used in the present invention is obtained by reacting a phenol other than o-cresol with an aldehyde.

As a single sheet constituting the novolac type phenol resin (A) used in the present invention The phenols of the body components are not particularly limited as long as they are phenols other than o-cresol. Examples thereof include cresols such as phenol, m-cresol, and p-cresol; 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, and 2,6-dimethyl a xylenol such as phenol, 3,4-xylenol or 3,5-xylenol; a tricresol such as 2,3,5-trimethylphenol or 2,3,6-trimethylphenol; o-ethylphenol; Ethylphenol such as acetol or p-acetol; alkylphenols such as cumene, butanol and p-tert-butylphenol; resorcinol, catechol, hydroquinone, pyrogallol Polyphenols such as phloroglucin; alkyl polyphenols such as alkyl resorcinol, alkyl catechol, alkyl hydroquinone (the carbon number of any alkyl group) 1~4). These may be used alone or in combination of two or more.

Among the above phenols, a combination of m-cresol and p-cresol, and a combination of m-cresol and 2,3,5-trimethylphenol are preferred. The combination of these components is used for the production of the novolac type phenol resin (A) by adjusting the blending ratio of each component, and the heat resistance, resolution, residual film ratio, and the like of the obtained resin composition for a photoresist can be adjusted. Various physical properties. When a combination of m-cresol and p-cresol is used as the phenol, the ratio of each component is not particularly limited, and it is preferably a weight ratio (m-cresol/p-cresol)=9/1 to 2/8, and further Good for 8/2~3/7. When the ratio of m-cresol is small, the sensitivity of the obtained resin composition for a photoresist is lowered. Further, when the ratio of p-cresol is small, the heat resistance, resolution, and residual film ratio of the obtained resin composition for a photoresist are lowered.

The aldehyde used in the novolac type phenol resin used in the present invention is not particularly limited, and examples thereof include formaldehyde, trioxane, triterpene, acetaldehyde, propionaldehyde, polyoxymethylene, and trichloroacetaldehyde. Hexamethylenetetramine, furfural, glyoxal, n-butyraldehyde, hexanal, allyl aldehyde, benzaldehyde, crotonaldehyde, acrolein, tetraformaldehyde, phenylacetaldehyde, o-tolualdehyde, salicylaldehyde Wait. Among these, in terms of the characteristics of the novolac type phenol resin obtained, it is preferred to use formaldehyde or trioxane.

In the present invention, the reaction molar ratio (A/P) of the aldehyde (A) to the phenol (P) is not particularly limited, but is preferably 0.5 to 1.5, more preferably 0.6 to 1.2.

By setting the above molar ratio, it is possible to obtain a weight which is particularly suitable for a photoresist. A novolac type phenol resin having an average molecular weight.

Next, the novolac type phenol resin (B) used in the present invention will be described. The novolac type phenol resin (B) is obtained by reacting a phenol composed of 30 to 100% by weight of o-cresol and 0 to 70% by weight of p-cresol with formaldehyde in the presence of an acid catalyst, and is obtained by coagulation. A novolac type phenol resin having a weight average molecular weight of 200 or more and less than 500 as measured by gel permeation chromatography (GPC).

The novolac type phenol resin (B) used in the present invention contains o-cresol or a combination of o-cresol and p-cresol as a monomer component. By adjusting the compounding ratio of each component of the above monomer component, the properties of the obtained resin composition for a photoresist can be adjusted, in particular, the sensitivity can be adjusted. The ratio of o-cresol to p-cresol is preferably a weight ratio (o-cresol/p-cresol) = 30/70 to 100/0.

In terms of the characteristics of the novolac type phenol resin (B) obtained, it is preferred to use formaldehyde or trioxane as the aldehyde used in the novolac type phenol resin (B).

The molecular weight of the novolac type phenol resin (B) is 200 or more and less than 500 by the GPC method. When the molecular weight is less than 200, the content of the low molecular component increases, and it volatilizes when baking the resin composition for a photoresist. When the molecular weight is 500 or more, the effect of improving the sensitivity of the resin composition for a photoresist is weakened.

The amount of the component (B) to be used in the present invention is 1 to 10 parts by weight, more preferably 1 to 7 parts by weight, per 100 parts by weight of the novolak-type phenol resin of the component (A). The component (B) is used in a small amount as an additive.

Further, the above weight average molecular weight is determined by gel permeation chromatography (GPC) and calculated based on a calibration curve prepared using a polystyrene standard material. The GPC measurement was carried out by using tetrahydrofuran as a solvent for dissolution at a flow rate of 1.0 ml/min and a column temperature of 40 °C.

The devices are used separately:

‧ Body: "HLC-8020" manufactured by TOSOH

‧Detector: "UV-8011" manufactured by TOSOH Corporation with a wavelength of 280 nm

‧ Analysis column: "SHODEX KF-802, KF-803, KF-805" manufactured by Showa Denko.

Examples of the acidic catalyst used for the reaction between the phenols and the aldehydes in the synthesis of (A) and (B) include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and boric acid, and organic acids such as oxalic acid, acetic acid, and p-toluenesulfonic acid. These can be used alone or in combination. Further, when the monomer is removed, it is preferably an acidic catalyst which can be easily removed from the reaction system by decomposition, sublimation or the like. Although the amount of use depends on the type of the catalyst, it is preferably set such that the pH in the reaction system is in the range of 1 to 6.

The method for producing the novolac type phenol resin of the present invention will be described based on the reaction sequence.

The reaction is carried out by adding a phenol or an acid catalyst to a reaction apparatus equipped with a stirrer, a thermometer, and a heat exchanger, and raising the temperature to a specific temperature. After reaching a certain temperature, formaldehyde is added successively. The sequential addition temperature or time can be appropriately set depending on the reactivity of the monomer to be used and the target characteristics of the obtained novolak-type phenol resin. Further, the production of the novolac type phenol resin can be set in a stable and economical manner.

The sequential addition time of formaldehyde is preferably from 30 to 300 minutes, and more preferably from 60 to 180 minutes. By setting the above-mentioned sequential addition time, the reaction can be carried out at an appropriate speed without rapid temperature rise.

Further, the sequential addition temperature of formaldehyde is preferably from 70 to 130 ° C, more preferably from 90 to 110 ° C. By setting the temperature as described above, the reaction can be carried out at an appropriate rate without rapid temperature rise.

After the above-mentioned sequential addition is completed, the reaction can be directly continued as needed. Further, when adding and reacting one by one, a reaction solvent may be added as needed. The type of the solvent is not particularly limited as long as it is a solvent capable of dissolving the phenol resin. Examples thereof include ketones such as methyl ethyl ketone and methyl isobutyl ketone; alcohols such as butanol; and ether alcohols such as ethoxyethanol.

After the above reaction, dehydration and de-monomerization are carried out under normal pressure and reduced pressure. A novolac type phenol resin is obtained. The conditions for dehydration and demonomerization are not limited. However, considering the stability (variation) or viscosity of the obtained novolak-type phenol resin, the degree of decompression is preferably about 0 to 200 Torr, and is taken out from the reaction apparatus. The temperature is preferably 130 to 200 °C.

Next, the sensitizer (C) used in the present invention will be described.

The sensitizer is not particularly limited, and examples thereof include the following components.

(1) 2,3,4-trihydroxydiphenyl ketone, 2,4,4'-trihydroxydiphenyl ketone, 2,4,6-trihydroxydiphenyl ketone, 2,3,6-three Hydroxydiphenyl ketone, 2,3,4-trihydroxy-2'-methyldiphenyl ketone, 2,3,4,4'-tetrahydroxydiphenyl ketone, 2,2',4,4' -tetrahydroxydiphenyl ketone, 2,3',4,4',6-pentahydroxydiphenyl ketone, 2,2',3,4,4'-pentahydroxydiphenyl ketone, 2,2' ,3,4,5-pentahydroxydiphenyl ketone, 2,3',4,4',5',6-hexahydroxydiphenyl ketone, 2,3,3',4,4',5' - polyhydroxydiphenyl ketones such as hexahydroxydiphenyl ketone; (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-hydroxyl) Phenyl)-2-propyl]phenyl]ethylidene)diphenol, 3,3'-dimethyl-{1-[4-[2-(3-methyl-4-hydroxyphenyl)- Bis[(poly)hydroxyphenyl]alkane such as 2-propyl]phenyl]ethylidene]diphenol; (3) tris(4-hydroxyphenyl)methane, bis(4-hydroxy-3,5- Dimethylphenyl)-4-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-4-hydroxyl Phenyl phenyl methane, bis(4-hydroxy-3,5-dimethylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-2-hydroxybenzene Methane, bis(4-hydroxy-2,5-dimethylphenyl)-3,4-dihydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-3,4 - Tris(hydroxyphenyl)methane such as dihydroxyphenylmethane or its methyl substituent; (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-hydroxyl -2-methylphenyl)-4-hydroxyphenylmethane, bis(3-cyclohexyl-2-hydroxyphenyl)-3-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-3- methyl Phenyl)-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-hydroxyphenylmethane, bis(3-cyclohexyl-2-hydroxyphenyl)-2- Hydroxyphenylmethane, bis(5-cyclohexyl-2-hydroxy-4-methylphenyl)-2-hydroxyphenylmethane, bis(5-cyclohexyl-2-hydroxy-4-methylphenyl)- Bis(cyclohexylhydroxyphenyl)(hydroxyphenyl)methane such as 4-hydroxyphenylmethane or a methyl substituent thereof, and naphthoquinone-1,2-diazide-5-sulfonic acid or naphthoquinone-1 a complete ester compound, a partial ester compound, a amide or a partial amide of a sulfonic acid or the like having a quinonediazide group such as 2-diazide-4-sulfonic acid or o-quinonediazidesulfonic acid.

In the resin composition of the present invention, the amount of the photosensitive agent (C) is not particularly limited, and is usually 5 to 70 parts by weight, preferably 10 to 50 parts by weight based on 100 parts by weight of the novolac type phenol resin (A). Share. When the amount of the sensitizer is large, the sensitivity of the obtained resin composition for a photoresist is lowered, and if it is small, a photoresist which is faithful to the mask pattern cannot be obtained.

Next, the solvent (D) used in the present invention will be described.

Examples of the solvent include ethylene glycol alkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether, and diethylene glycol dimethyl ether. , diethylene glycol dialkyl ethers such as diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, 2-methyloxyl acetate (2-methylethoxylate), 2- Ethylene glycol alkyl ether acetate such as ethoxyethyl acetate, propylene glycol alkyl ether acetate such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, acetone , ketones such as methyl ethyl ketone, cyclohexanone, methyl amyl ketone, cyclic ethers such as dioxane, and methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, 2 -ethyl hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, butyl 3-methoxyacetate, 3-methyl An ester such as -3-methoxyacetic acid butyl ester, ethyl formate, ethyl acetate, butyl acetate, methyl acetonitrile acetate or ethyl acetate. These may be used alone or in combination of two or more.

The content of the above solvent is not particularly limited, but is preferably a solid content concentration The total amount of the resin composition is adjusted to be 30 to 65 wt%. By setting the solid content concentration to the above range, the fluidity of the resin composition can be improved, and a uniform photoresist film can be obtained.

In addition to the components described above, the resin composition of the present invention may optionally contain various additives such as a surfactant, an adhesion promoter, and a dissolution promoter.

The method for preparing the resin composition of the present invention is not particularly limited. However, when a filler or a pigment is not added to the resin composition, the components may be mixed and stirred by a usual method, and a filler may be added thereto. In the case of a pigment, for example, it may be dispersed and mixed using a dispersing device such as a dispersing mixer, a homogenizer or a three-roll mill. Further, it is also possible to perform filtration using a sieve filter, a membrane filter, or the like as needed.

The resin composition of the present invention obtained in this manner is exposed through a mask, whereby a structural change occurs in the resin composition in the exposed portion, and the solubility in the alkaline developer can be promoted. On the other hand, since the low solubility of the alkaline developing solution is maintained in the unexposed portion, the photoresist function can be imparted by the difference in solubility thus produced.

However, the novolac type phenol resin used in the high heat resistant photoresist generally has a large amount of high molecular weight, and it is difficult to prepare a photoresist having both heat resistance and sensitivity. By adding a small amount of the novolac type phenol resin (B) synthesized by the present invention, the sensitivity can be improved without lowering the properties such as heat resistance of the resin composition.

[Examples]

Hereinafter, the present invention will be described by way of examples. However, the invention is not limited by the embodiments. In addition, the "parts" described in the synthesis examples, the examples, and the comparative examples are "parts by weight", and "%" means "% by weight". Further, the content of the free monomer was calculated based on the area ratio obtained by GPC measurement.

1. Synthesis of novolac type phenolic resin (B)

Synthesis Example 1

Into a four-necked flask equipped with a stirrer, a thermometer, and a heat exchanger, 1000 parts of o-cresol and 5 parts of oxalic acid were placed, and the internal temperature was raised to 97 to 103 °C. After the temperature was reached, 750 parts of 37% marinar was added over 3 hours while maintaining the internal temperature of 97-103 ° C (adding molar ratio of all phenols to mulberry (A) / all phenols (C) = 1.000). Thereafter, the mixture was refluxed for 2 hours, and then dehydrated and subjected to monomer removal under normal pressure until 180 ° C to obtain 800 parts of a novolac type phenol resin (1). The weight average molecular weight of the obtained resin was 400.

Synthesis Example 2

Into a four-necked flask equipped with a stirrer, a thermometer, and a heat exchanger, 500 parts of o-cresol, 500 parts of p-cresol, and 5 parts of oxalic acid were placed, and the internal temperature was raised to 97 to 103 °C. After the temperature was reached, 750 parts of 37% formalin was added over 3 hours while maintaining the internal temperature of 97 to 103 ° C (addition of molar ratio A/C = 1.000 to all phenols), followed by a reflux reaction for 2 hours. Then, dehydration and de-monomerization were carried out under normal pressure until 180 ° C to obtain 850 parts of a novolac type phenol resin (2). The weight average molecular weight of the obtained resin was 400.

2. Preparation of resin composition for photoresist

Example 1

5 parts by weight of the novolac type phenol resin (1) synthesized in Synthesis Example 1 was added to 100 parts by weight of the resin of m-cresol/p-cresol=5/5 and Mw=25,000, and the naphthoquinone 1,2-double stack was mixed. 20 parts by weight of 2,3,4-trihydroxydiphenyl ketone of nitrogen-5-sulfonic acid, and dissolved in 300 parts of propylene glycol monomethyl ether acetate (PGMEA), followed by filtration using a membrane filter having a pore size of 1.0 μm. A resin composition for a positive photoresist is prepared.

Example 2

5 parts by weight of the novolac type phenol resin (2) synthesized in Synthesis Example 2 was added to 100 parts by weight of the resin of m-cresol/p-cresol=5/5 and Mw=25,000, and the naphthoquinone 1,2-double stack was mixed. 20 parts by weight of 2,3,4-trihydroxydiphenyl ketone of nitrogen-5-sulfonic acid, and dissolved in 300 parts of propylene glycol monomethyl ether acetate (PGMEA), followed by filtration using a membrane filter having a pore size of 1.0 μm. , preparing resin for positive photoresist Composition.

Example 3

To 100 parts by weight of the resin of m-cresol/2,3,5-trimethylphenol=8/2 and Mw=20,000, 5 parts by weight of the novolac type phenol resin (1) synthesized in Synthesis Example 1 was added, and naphthoquinone 1 was mixed. 20 parts by weight of 2,3,4-trihydroxydiphenyl ketone ester of 2-diazide-5-sulfonic acid, and dissolved in 300 parts of propylene glycol monomethyl ether acetate (PGMEA), followed by a pore size of 1.0 μm. The membrane filter was filtered to prepare a resin composition for a positive photoresist.

Example 4

5 parts by weight of the novolac type phenol resin (2) synthesized in Synthesis Example 2 was added to 100 parts by weight of the resin of m-cresol/p-cresol=5/5 and Mw=20,000, and the naphthoquinone 1,2-double stack was mixed. 20 parts by weight of 2,3,4-trihydroxydiphenyl ketone of nitrogen-5-sulfonic acid, and dissolved in 300 parts of propylene glycol monomethyl ether acetate (PGMEA), followed by filtration using a membrane filter having a pore size of 1.0 μm. A resin composition for a positive photoresist is prepared.

3. Synthesis of novolac type phenolic resin (comparative object of B)

Comparative Synthesis Example 1

In a four-necked flask equipped with a stirrer, a thermometer, and a heat exchanger, 500 parts of o-cresol, 500 parts of p-cresol, and 5 parts of oxalic acid were placed, and the internal temperature was raised to 97 to 103 °C. After the temperature was reached, 688 parts of 37% humamine (addition of molar ratio A/C = 1.100 to all phenols) was added for 3 hours while maintaining the internal temperature of 97 to 103 ° C, and thereafter, a reflux reaction was carried out for 2 hours. Then, dehydration and de-monomerization were carried out under normal pressure until 180 ° C to obtain 850 parts of a novolac type phenol resin (3). The weight average molecular weight of the obtained resin was 600.

Comparative Synthesis Example 2

In a four-necked flask equipped with a stirrer, a thermometer, and a heat exchanger, 500 parts of o-cresol, 500 parts of p-cresol, and 5 parts of oxalic acid were placed, and the internal temperature was raised to 97 to 103 °C. After the temperature was reached, 750 parts of 37% marinar was added over 3 hours while maintaining the internal temperature of 97-103 ° C (relative to total phenol). After adding a molar ratio of A/C = 1.200), a reflux reaction was carried out for 2 hours, and then dehydration and de-monomerization were carried out under normal pressure until 180 ° C to obtain 850 parts of a novolac type phenol resin (4). The weight average molecular weight of the obtained resin was 1200.

4. Preparation of composition for photoresist

Comparative example 1

Mixing 2,3,4-trihydroxydiphenyl ketone of naphthoquinone 1,2-diazide-5-sulfonic acid with 100 parts by weight of m-cresol/p-cresol=5/5, Mw=25,000 resin 20 parts by weight of the ester was dissolved in 300 parts of propylene glycol monomethyl ether acetate (PGMEA), and then filtered using a membrane filter having a pore size of 1.0 μm to prepare a resin composition for a positive photoresist.

Comparative example 2

5 parts by weight of the novolac type phenol resin (3) synthesized in Synthesis Example 1 was added to 100 parts by weight of the resin of m-cresol/p-cresol=5/5 and Mw=25,000, and naphthoquinone 1,2- was mixed. 20 parts by weight of 2,3,4-trihydroxydiphenyl ketone ester of diazide-5-sulfonic acid, after dissolving in 300 parts of propylene glycol monomethyl ether acetate (PGMEA), using a membrane filter having a pore size of 1.0 μm Filtration was carried out to prepare a resin composition for a positive photoresist.

Comparative example 3

5 parts by weight of the novolac type phenol resin (4) synthesized in Comparative Synthesis Example 2 was added to 100 parts by weight of the resin of m-cresol/p-cresol=5/5 and Mw=25,000, and naphthoquinone 1,2- was mixed. 20 parts by weight of 2,3,4-trihydroxydiphenyl ketone ester of diazide-5-sulfonic acid, after dissolving in 300 parts of propylene glycol monomethyl ether acetate (PGMEA), using a membrane filter having a pore size of 1.0 μm Filtration was carried out to prepare a resin composition for a positive photoresist.

Comparative example 4

12 parts by weight of the novolac type phenol resin (1) synthesized in Synthesis Example 1 was added to 100 parts by weight of a resin of m-cresol/p-cresol=5/5 and Mw=25,000, and naphthoquinone 1,2-di was mixed. 20 parts by weight of azide-5-sulfonic acid 2,3,4-trihydroxydiphenyl ketone ester, dissolved in propylene glycol monomethyl ether acetate (PGMEA) After 300 parts, it was filtered using a membrane filter having a pore size of 1.0 μm to prepare a resin composition for a positive type resist.

Further, the weight average molecular weight of the novolac type phenol resin was determined by gel permeation chromatography (GPC) and calculated based on a calibration curve prepared using a polystyrene standard material. The GPC measurement was carried out by using tetrahydrofuran as a solvent for dissolution at a flow rate of 1.0 ml/min and a column temperature of 40 °C.

The devices are used separately:

‧ Body: "HLC-8020" manufactured by TOSOH

‧Detector: "UV-8011" manufactured by TOSOH Corporation with a wavelength of 280 nm

‧ Analysis column: "SHODEX KF-802, KF-803, KF-805" manufactured by Showa Denko. Using the photoresist resin compositions obtained in Examples 1 to 4 and Comparative Examples 1 to 4, the characteristics evaluation described below was carried out. The results are shown in Table 1.

4. Evaluation method of characteristics

(1) Evaluation method of heat resistance

The resin composition for a photoresist was applied onto a ruthenium hexamethyldiazane-treated ruthenium wafer by a spin coater at a film thickness of 1.5 μm, and dried on a hot plate at 110 ° C. 100 seconds. Thereafter, exposure was performed through a test chart mask using a reduced projection exposure apparatus, and development was carried out using a developing solution (2.38% tetramethylammonium hydroxide aqueous solution) for 60 seconds. The obtained silicon wafer was placed on a hot plate having a different temperature for 3 minutes, and the shape of the photoresist pattern on the germanium wafer was observed by a scanning electron microscope, and the temperature at which the normal photoresist pattern could not be obtained was set. Heat resistant temperature.

(2) Method for measuring sensitivity

The resin composition for a photoresist was applied onto a 4 inch silicon wafer by a spin coater to a thickness of about 1 μm, and dried on a hot plate at 110 ° C for 100 seconds. Then, the test chart mask is overlapped with the germanium wafer, and irradiated with ultraviolet rays of 20 mJ/cm ² , 40 mJ/cm ² , 60 mJ/cm ² , and 80 mJ/cm ² , respectively, using a developing solution (2.38% of four The aqueous solution of ammonium hydroxide was developed for 60 seconds. The pattern shape was observed by a scanning electron microscope on the obtained pattern, and the evaluation was performed on the following basis.

A does not reach 20 mJ/cm ² and can form an image.

B 20 mJ/cm ² or more and less than 40 mJ/cm ² can form an image.

An image can be formed at C 40 mJ/cm ² or more and less than 60 mJ/cm ² .

An image can be formed by D 60 mJ/cm ² or more and less than 80 mJ/cm ² .

E 80 mJ/cm ² or more, an image cannot be formed.

The sensitivity of the photoresist is preferably a region of A or B in terms of steps, and if it is a region below C, the sensitivity is too low and it is difficult to use.

(3) residual film rate

The resin composition was applied onto a 4 inch silicon wafer by a spin coater to a thickness of about 1 μm, 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 film thickness after immersion in the developing solution is expressed as a percentage with respect to the film thickness before being immersed in the developing solution. Therefore, a larger residual film ratio indicates that the residual film property is good.

From the results of Table 1, it was confirmed that Examples 1 to 4 are the groups for the photoresist of the present invention. The object was improved in sensitivity without lowering various physical properties such as heat resistance as compared with Comparative Examples 1 to 4 which were not used.

Since the resin composition of Comparative Example 1 did not use the novolak-type phenol resin (B) for improving the sensitivity, the sensitivity was low.

In the resin compositions of Comparative Examples 2 and 3, the molecular weight of the novolac type phenol resin (B) for improving the sensitivity was high, and the effect of improving the sensitivity was small.

In the resin composition of Comparative Example 4, since the addition amount of the novolak-type phenol resin (B) for improving the sensitivity was large, the residual film ratio was largely lowered.

By adding an appropriate amount of the novolac type phenol resin (B) having a specific monomer composition and molecular weight, the sensitivity can be improved without lowering the physical properties of the photoresist.

[Industrial availability]

The resin composition for a photoresist of the present invention using the novolac type phenol resin of the present invention has good physical properties such as good thermal stability and high sensitivity, and thus can be preferably used for a liquid crystal display device circuit or Microcircuit fabrication of semiconductor integrated circuits.

Claims (1)

A resin composition for a photoresist comprising: (A) 100 parts by weight of a novolak type phenol resin containing no o-cresol component; (B) 1 to 10 parts by weight of a novolak type phenol resin, by adjacent The phenol of 30 to 100% by weight of phenol and 0 to 70% by weight of p-cresol are reacted with formaldehyde in the presence of an acidic catalyst, and the weight average molecular weight measured by GPC is 200 or more and less than 500; (C) sensitizer; and (D) solvent.