KR102515382B1 - Phenolic resin composition for photoresist and photoresist composition - Google Patents

Abstract

The novolak-type phenolic resin (A) represented by the general formula (1) and the novolak-type phenolic resin (B) containing at least one of an arylene skeleton and a naphthalene skeleton in the structure, the mass ratio of (A) and (B) is 5 It is a phenolic resin composition for photoresists, characterized in that it is contained in an amount of ~ 95:95 ~ 5. (In general formula (1), R ₁ represents hydrogen or a linear or branched alkyl group having 1 to 8 carbon atoms, which may be the same or different. However, at least one of R ₁ has 1 to 8 carbon atoms. is a linear or branched alkyl group of , p is 1 or more and 3 or less, which may be the same or different, q is 1 or more and 3 or less, which may be the same or different, provided that p+q≤4, n is 0 Indicates an integer above.)

Description

Phenolic resin composition for photoresist and photoresist composition

The present invention relates to a phenolic resin composition for photoresists and a photoresist composition comprising the phenolic resin composition for photoresists.

In recent years, the line width of circuit patterns of integrated circuit semiconductors has been miniaturized along with high density integration. Also in liquid crystal display elements and the like, similarly, the line width tends to be thin and miniaturized. BACKGROUND OF THE INVENTION [0002] As display panels are becoming larger and lower in cost, there is a need for a technology capable of stably forming wires in a simple process on a large substrate.

In addition, among the photolithography techniques conventionally used in the semiconductor field, a process of patterning a resist film and then forming a wire by a wet etching method or a dry etching method is widespread, and the technology is also applied to the manufacturing process of a liquid crystal display device. there is

Accordingly, the performance requirements for photoresist resin materials are also highly sophisticated and diversified, and high developability such as high sensitivity, high film retention rate, and high resolution, and etching resistance such as wet etching resistance and dry etching resistance are required.

A cresol novolak-type phenol resin is the most widely used phenol resin for use in photoresists (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2-55359

However, the cresol novolak-type phenolic resin described in Patent Literature 1 is not capable of meeting the performance requirements of today's highly sophisticated and diversified market, and has insufficient etching resistance.

Accordingly, an object of the present invention is to provide a phenolic resin composition for a photoresist and a photoresist composition having high developability such as high sensitivity, high remaining film rate and high resolution, and further excellent in etching resistance.

As a result of intensive examination to solve the above problems, the present inventors have found that a novolac-type phenolic resin (A) represented by a specific general formula and a novolak-type phenolic resin (B) containing a specific structure of an arylene skeleton or naphthalene skeleton in a resin skeleton It was found that a photoresist composition using a phenolic resin composition for photoresist obtained by polymer blending has excellent developability such as high sensitivity, high remaining film rate and high resolution, and excellent etching resistance, and the present invention has been reached.

That is, the present invention relates to the following matters.

1. A novolak-type phenolic resin (A) represented by the following general formula (1) and a novolak-type phenolic resin (B) containing at least one of an arylene skeleton and a naphthalene skeleton in the structure of (A) and (B) It relates to a phenolic resin composition for photoresist comprising an amount such that the mass ratio is 5 to 95:95 to 5.

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(In general formula (1), R ₁ represents hydrogen or a linear or branched alkyl group having 1 to 8 carbon atoms, which may be the same or different. However, at least one of R ₁ has 1 to 8 carbon atoms. is a linear or branched alkyl group of , p is 1 or more and 3 or less, which may be the same or different, q is 1 or more and 3 or less, which may be the same or different, provided that p+q≤4, n is 0 Indicates an integer above.)

2. In the above 1., the novolac-type phenolic resin (B) relates to a phenolic resin composition for photoresists containing in its structure a unit represented by the following general formula (4).

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(In general formula (4), X represents a divalent group represented by the following formula (4-1) or (4-2).

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R ₂ represents hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 3 to 6 carbon atoms, a phenyl group, or a halogen. a is 1 or 2; b is 1 or more and 3 or less, and when b is 2 or more, R ₂ may be the same or different. However, a+b≤4. On the other hand, when a plurality of units represented by the general formula (4) are included in the structure of the novolac-type phenolic resin (B), a plurality of a, b and R ₂ contained in the structure of the novolak-type phenolic resin (B) are respectively may be the same or different.)

3. In the above 1, the novolak-type phenolic resin (B) relates to a phenolic resin composition for photoresists containing in its structure a unit represented by the following general formula (10).

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(In Formula (10), R ₃ is hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 3 to 6 carbon atoms, a phenyl group, a halogen atom, a carboxyl group, an alkoxy group, an acetyl group, a sulfonic acid Represents a sodium group, a nitro group, or an amino group. R ₄ represents hydrogen or a methyl group. c is 1 or more and 3 or less, and when c is 2 or more, each R ₃ may be the same or different. On the other hand, novolak-type phenol When a plurality of units represented by the general formula (10) are included in the structure of the resin (B), a plurality of c, R ₄ and R ₃ contained in the structure of the novolak-type phenolic resin (B) may be the same or different, respectively. )

4. It is related with the photoresist composition containing the phenolic resin composition for photoresists described in any one of said 1. to 3. and a photosensitizer.

According to the present invention, it is possible to provide a phenolic resin composition for a photoresist and a photoresist composition having high developability such as high sensitivity, high remaining film rate and high resolution, and further excellent in etching resistance.

The phenolic resin composition for photoresists of the present invention comprises a novolac-type phenolic resin (A) represented by the following general formula (1) and a novolac-type phenolic resin (B) containing at least one of an arylene skeleton and a naphthalene skeleton in its structure. It is obtained by polymer blending (mixing).

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(In general formula (1), R ₁ represents hydrogen or a linear or branched alkyl group having 1 to 8 carbon atoms, which may be the same or different. However, at least one of R ₁ has 1 to 8 carbon atoms. is a linear or branched alkyl group of , p is 1 or more and 3 or less, which may be the same or different, q is 1 or more and 3 or less, which may be the same or different, provided that p+q≤4, n is 0 Indicates an integer above.)

The phenolic resin composition for photoresist according to the present invention contains the novolak-type phenolic resin (A) and the novolak-type phenolic resin (B) together, so that when a photoresist composition is used, developability such as high sensitivity, high film retention rate, high resolution, etc. , and the etching resistance such as wet etching resistance and dry etching resistance is both excellent.

[Novolak-type phenolic resin (A)]

In the phenolic resin composition for photoresists of the present invention, the novolak-type phenolic resin (A) is represented by the above general formula (1).

In the novolak-type phenolic resin (A) represented by the above general formula (1), R ₁ represents a substituent bonded to a benzene ring having a phenolic hydroxyl group. R ₁ represents hydrogen or a linear or branched alkyl group having 1 to 8 carbon atoms, and a plurality of R ₁ contained in the structure of the novolak-type phenolic resin (A) may be the same or different. However, at least one of R ₁ is a linear or branched alkyl group having 1 to 8 carbon atoms. That is, the novolak-type phenolic resin (A) always has an alkyl-substituted phenol skeleton in which an alkyl group is bonded as substituent R ₁ to a benzene ring having a phenolic hydroxyl group. R ₁ is preferably hydrogen, a methyl group, an ethyl group, a propyl group, a butyl group, a t-butyl group, a propyl group, a vinyl group or an octyl group. From the viewpoints of sensitivity, remaining film rate, resolution, and heat resistance when used as a phenolic resin composition for photoresists, it is more preferable that R ₁ is a methyl group.

In the novolak-type phenolic resin (A) represented by the general formula (1), q represents the number of substituents R ₁ . q is an integer of 1 or more and 3 or less, and may be the same or different, respectively. Here, "they may be the same or different" in q indicates that a plurality of q contained in the structure of the novolak-type phenolic resin (A) may be the same or different. It is preferable that all of q are 1 from a viewpoint of the balance of sensitivity, remaining film rate, resolution, and heat resistance when used as a phenolic resin composition for photoresists.

In the novolac-type phenolic resin (A) represented by the general formula (1), p represents the number of phenolic hydroxyl groups. p is an integer of 1 or more and 3 or less, and may be the same or different, respectively. Here, “they may be the same or different” in p indicates that a plurality of ps included in the structure of the novolac-type phenolic resin (A) may be the same or different. However, the sum of p+q with the number q of substituents R ₁ described above is 4 or less. It is preferable that all of p are 1 from a viewpoint of the balance of sensitivity, remaining film rate, resolution, and heat resistance when used as a phenolic resin composition for photoresists. When the number of phenolic hydroxyl groups is large, the dissolution rate in alkali becomes excessively high, and handling properties when used as a photoresist composition may be poor.

In the novolac-type phenolic resin (A) represented by the above general formula (1), n represents the number of repetitions and is an integer of 0 or greater.

Since the novolac-type phenolic resin (A) represented by the general formula (1) is an aggregate of polymers having various molecular weights, the value of n can be expressed as an average value n' in the aggregate.

The average value n' is preferably a value such that the weight average molecular weight (Mw) in terms of polystyrene, measured by GPC (gel permeation chromatography) of the novolac-type phenolic resin (A), is 1000 to 50000, and is 1500 to It is more preferably a value of 30000, more preferably a value of 1500 to 25000, particularly preferably a value of 3000 to 15000, and most preferably a value of 5000 to 12000.

The novolak-type phenolic resin (A) represented by the general formula (1) has a weight average molecular weight (Mw) in terms of polystyrene measured by GPC (gel permeation chromatography) in the above-mentioned range as a phenolic resin composition for photoresists. It is preferable from the viewpoints of handling properties in manufacturing and sensitivity, remaining film rate, resolution, and heat resistance when used as a photoresist composition. When the weight average molecular weight is smaller than 1000, the sensitivity may be too high or the heat resistance may be poor, and when the weight average molecular weight is larger than 50000, the sensitivity may be low.

The hydroxyl equivalent of the novolac-type phenolic resin (A) represented by the general formula (1) is preferably 90 g/eq or more and 140 g/eq or less from the viewpoint of the balance of sensitivity, remaining film rate, resolution, and heat resistance when used as a photoresist composition. and more preferably 100 g/eq or more and 135 g/eq or less, and more preferably 100 g/eq or more and 130 g/eq or less.

In addition, one of the more preferable aspects of the novolak-type phenolic resin (A) represented by the above general formula (1) is that all p and q in general formula (1) are 1 (p = 1, q = 1), all substituents It is a cresol novolac resin represented by the following general formula (2) in which R is a methyl group.

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(In Formula (2), n is the same as defined in Formula (1) above.)

The use of the cresol novolac resin represented by the general formula (2) as the novolak-type phenolic resin (A) is preferable because it is possible to obtain a photoresist composition having a well-balanced sensitivity, remaining film rate, resolution, and heat resistance.

In the novolak-type phenolic resin (A), which is one of the preferable embodiments represented by the above general formula (2), the methyl group may be positioned at any ortho, meta, or para position with respect to the phenolic hydroxyl group. From the viewpoint of having a well-balanced sensitivity, remaining film rate, resolution, and heat resistance when used as a photoresist composition, it is preferable to have a structure having both a phenol skeleton in which a methyl group is substituted at the meta position of the phenolic hydroxyl group and a phenol skeleton in which a methyl group is bonded to the para position. do. It is more preferable that the novolac-type phenolic resin (A) has a structure composed of a phenol skeleton in which a methyl group is substituted at a meta-position to a phenolic hydroxyl group, and a phenol skeleton in which a methyl group is bonded to a para-position. The molar ratio of metawi:parawi can be adjusted by adjusting the molar ratio of the phenolic compound (a1) at the time of introducing the raw material to be described later. At that time, the phenol skeleton in which the methyl group is substituted at the meta position of the general formula (2) and the phenol skeleton in which the methyl group is bonded to the para position are meta position: the molar ratio at the time of feeding the para position is 20 to 80: 80 to 20 The amount is preferably 30 to 70:70 to 30, more preferably 40 to 60:60 to 40, and particularly preferably 40 to 50:60 to 50.

The position of the methyl group in the phenol skeleton in the structure of the novolac-type phenolic resin (A) affects the etching resistance and alkali solubility of the resist composition. A photoresist composition with high etching resistance can be obtained by increasing the number of phenol skeletons in which methyl groups are bonded to para. It is preferable that the proportion of parawie exceeds 50%. When there is a large ratio of metaweed, there is a concern that the alkali dissolution rate is increased and the problem that the remaining film rate is lowered may occur. If the rate of metawi is up to 50%, there is no such concern.

[Method for producing novolak-type phenolic resin (A)]

The novolak-type phenolic resin (A) represented by the general formula (1) can be obtained by condensation polymerization of a phenolic compound (a1) represented by the following general formula (3) and formaldehyde (a2) under an acidic catalyst.

<Phenol compound (a1)>

The phenolic compound (a1) used in the manufacture of the novolac-type phenolic resin (A) is represented by the following general formula (3).

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(In Formula (3), R ₁ , p and q are the same as defined in Formula (1) above.)

Examples of the phenolic compound represented by the general formula (3) are not particularly limited, but examples of p=1 compounds include phenol, m-cresol, p-cresol, o-cresol, 2,3-xylenol, 2,4- Xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, 2,3,5-trimethylphenol, 2,3,6 -Trimethylphenol, 4-t-butylphenol, p-octylphenol, dibutylphenol, etc. are mentioned.

In addition, as a compound of p=2, catechol, resorcinol, hydroquinone, etc. are mentioned. Among them, resorcin is suitable.

Moreover, as a compound of P=3, hydroxyquinol, phloroglycinol, a pyrogallol, etc. are mentioned.

These phenol compounds can be used individually by 1 type or in combination of 2 or more types. However, an alkyl-substituted phenolic compound in which R ₁ is a linear or branched alkyl group having 1 to 8 carbon atoms is included as an essential component.

In particular, it is preferable to use cresols such as m-cresol, p-cresol, and o-cresol as the phenol compound (a1) from the viewpoint of providing a well-balanced sensitivity, remaining film rate, resolution, and heat resistance when used as a photoresist composition. , It is more preferable to use m-cresol or p-cresol, and it is more preferable to use a combination of m-cresol and p-cresol.

When m-cresol and p-cresol are used in combination, the molar ratio of m-cresol:p-cresol is preferably 20 to 80:80 to 20, and more preferably 30 to 70:70 to 30. It is preferable, and it is more preferable that it is 40-60:60-40, and it is especially preferable that it is 40-50:60-50.

<Formaldehyde (a2)>

The formaldehyde (a2) is not particularly limited, but an aqueous formaldehyde solution may be used, or a polymer that decomposes to formaldehyde in the presence of an acid such as paraformaldehyde or trioxane may be used. Preferably, it is an aqueous formaldehyde solution that is easy to handle, and a commercially available 42% formaldehyde aqueous solution can be suitably used as it is.

<Molar ratio of phenolic compound (a1) to formaldehyde (a2) (a2/a1)>

When reacting the phenolic compound (a1) with formaldehyde (a2) in the production of the novolak-type phenolic resin (A), preferably 0.2 to 1.0 mol of formaldehyde (a2) is added to 1 mol of the phenolic compound (a1). More preferably, it is set as 0.5-0.9 mol.

By setting the molar ratio of the phenolic compound (a1) to the formaldehyde (a2) within the above range, the weight average molecular weight (Mw) of the novolac-type phenolic resin (A) used in the present invention can be set within a preferred range.

<acid catalyst>

The reaction conditions for the polycondensation reaction in the production of the novolac-type phenolic resin (A) of the present invention may be conventionally known reaction conditions applied when preparing a normal phenolic resin. That is, the acid catalyst used is not particularly limited as long as it is an acid capable of reacting a phenol component with a formaldehyde component, and examples thereof include organic sulfonic acids such as oxalic acid, benzenesulfonic acid, p-toluenesulfonic acid, and methanesulfonic acid. Inorganic acids, such as hydrochloric acid and sulfuric acid, etc. can be used individually or in combination of 2 or more types. Among them, sulfuric acid, oxalic acid or p-toluenesulfonic acid is particularly preferred.

The amount of acid catalyst used is about 0.01 to 1% by mass relative to the phenol component (a1). When the novolak-type phenolic resin (A) is used in the photoresist composition, the acid catalyst remaining in the resin may affect the properties of the photoresist, so the one where it is as small as possible is preferable. The preferred usage amount varies depending on the type, and it is preferable to use 0.3 to 1.0% by mass in the case of oxalic acid, 0.05 to 0.1% by mass in the case of sulfuric acid, and 0.1 to 0.5% by mass in the case of p-toluenesulfonic acid.

<Reaction solvent>

As the reaction solvent, water included in formaldehyde as a raw material may serve as a solvent. In addition to water, an organic solvent that does not affect the reaction may be used as necessary. Examples of these organic solvents include ethers such as diethylene glycol dimethyl ether, 1,2-dimethoxyethane, and 1,2-diethoxyethane; esters such as propylene glycol monomethyl ether acetate; Cyclic ethers, such as tetrahydrofuran and a dioxane, etc. are mentioned.

The amount of the reaction solvent used is preferably 20 to 1000 parts by mass per 100 parts by mass of the reaction raw material.

<reaction temperature>

The reaction temperature of the polycondensation reaction is not particularly limited, and is usually 50 to 200°C, preferably 70 to 180°C, and more preferably 80 to 170°C. When the temperature is lower than 50°C, the reaction is difficult to proceed, and when the temperature exceeds 200°C, reaction control becomes difficult, and it becomes difficult to stably obtain the target novolak-type phenolic resin (A).

<Reaction time, reaction pressure>

Although the reaction time of the polycondensation reaction also depends on the reaction temperature, it is usually about 0.1 to 20 hours. In addition, the reaction pressure of the polycondensation reaction is usually carried out under normal pressure, but may be carried out under increased pressure or reduced pressure.

<Post-processing>

As a post-treatment after completion of the polycondensation reaction, it is preferable to neutralize the acid catalyst by adding a base to completely stop the reaction, and then to wash with water by adding water to remove the acid catalyst.

The base for neutralizing the acid catalyst is not particularly limited, and any base that neutralizes the acid catalyst and forms a water-soluble salt can be used. inorganic bases such as metal hydroxides and metal carbonates; and organic bases such as amines and organic amines. Specific examples of the inorganic base include sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium hydrogencarbonate, calcium carbonate and the like. Specific examples of organic base amines or organic amines include ammonia, trimethylamine, triethylamine, diethylamine, and tributylamine. Organic amines are preferably used. The amount used also depends on the amount of the acid catalyst, but it is preferable to neutralize the acid catalyst and use it in an amount such that the pH in the reaction system falls within the range of 4 to 8.

The amount of water used in water washing and the number of times of water washing are not particularly limited, but the number of washings is preferably about 1 to 5 times in order to remove the acid catalyst to an amount that does not affect actual use, including from an economic point of view. In addition, the water washing temperature is not particularly limited, but it is preferably carried out at 40 to 95 ° C. from the viewpoint of the efficiency of catalytic species removal and workability. When the separation between the novolac-type phenolic resin (A) and the washing water is poor during washing, it is effective to add a solvent or increase the washing temperature in order to reduce the viscosity of the mixture. Although the type of solvent is not particularly limited, any solvent that dissolves the novolak-type phenol resin (A) and lowers the viscosity can be used.

After removing the acidic catalyst, the temperature of the reaction system is usually raised to 130 to 230 ° C., for example, under reduced pressure of 20 to 50 torr, by evaporating volatile components such as unreacted raw materials and organic solvents remaining in the reaction mixture, The target novolac-type phenolic resin (A) can be suitably separated and recovered.

[Novolak-type phenolic resin (B)]

In the phenolic resin composition for photoresists of the present invention, the novolak-type phenolic resin (B) includes at least one of an arylene skeleton and a naphthalene skeleton in its structure. The phenolic resin composition for photoresists of the present invention contains a novolak-type phenolic resin (B), so that, when used as a photoresist composition, developability such as high sensitivity, high remaining film rate, and high resolution, and etching resistance such as wet etching resistance and dry etching resistance Together they become great.

[Novolac-type phenolic resin (B) containing an arylene skeleton in its structure]

In the novolak-type phenolic resin (B), including an arylene skeleton in the structure means that at least one unit (structural unit) of the following general formula (4) is included in the structure.

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(In general formula (4), X represents a divalent group represented by the following formula (4-1) or (4-2).

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R ₂ represents hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 3 to 6 carbon atoms, a phenyl group, or halogen. a is 1 or 2; b is 1 or more and 3 or less, and when b is 2 or more, R ₂ may be the same or different. However, a+b≤4. On the other hand, when a plurality of units represented by the general formula (4) are included in the structure of the novolac-type phenolic resin (B), a plurality of a, b and R ₂ contained in the structure of the novolak-type phenolic resin (B) are respectively may be the same or different.)

In the unit represented by the general formula (4), R ₂ represents a substituent bonded to a benzene ring having a phenolic hydroxyl group. R ₂ represents hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 3 to 6 carbon atoms, a phenyl group, or halogen. R ₂ is preferably hydrogen, methyl, ethyl, propyl, butyl, t-butyl or propyl, more preferably hydrogen or methyl, still more preferably hydrogen is a phenolic resin composition for photoresists It is preferable from the viewpoint of the balance of the sensitivity, remaining film rate, resolution, heat resistance, and etching resistance when used as a photoresist composition and handling properties in manufacturing when used as a photoresist composition.

In the unit represented by the general formula (4), b represents the number of substituents R ₂ . b is an integer of 1 or more and 3 or less, and when b is 2 or more, R ₂ may be the same or different. It is preferable that b is 1 from a viewpoint of the balance of sensitivity, remaining film rate, resolution, heat resistance, and etching resistance when used as a phenolic resin composition for photoresists.

Further, when a plurality of units represented by the general formula (4) are included in the structure of the novolak-type phenolic resin (B), a plurality of b and R ₂ contained in the structure of the novolak-type phenolic resin (B) are each the same or It can be different.

In the unit represented by the general formula (4), a represents the number of phenolic hydroxyl groups. a is 1 or 2; However, the sum of a+b with the number b of substituents R ₂ described above is 4 or less. It is preferable that a is 1 from a viewpoint of the balance of sensitivity, remaining film rate, resolution, heat resistance, and etching resistance when used as a phenolic resin composition for photoresists.

In the case where a plurality of units represented by the general formula (4) are included in the structure of the novolac-type phenolic resin (B), the plurality of as included in the structure of the novolak-type phenolic resin (B) may be the same or different. That is, the novolac-type phenolic resin (B) may include the skeleton of monohydric phenol (a = 1) and the skeleton of dihydric phenol (a = 2) in the same structure.

The weight average molecular weight (Mw) in terms of polystyrene measured by GPC (gel permeation chromatography) of the novolak-type phenolic resin (B) containing an arylene skeleton in its structure is 300 to 10000 is preferable, 500 to 8000 is more preferable, 500 to 5000 is still more preferable, 1000 to 1500 is particularly preferable, and 1200 to 1400 is extremely preferable from the viewpoint of handling properties and performance when used as a photoresist composition. do. When the weight average molecular weight is smaller than 300, the sensitivity may be too high or the heat resistance may be inferior, and when the weight average molecular weight is larger than 10000, the sensitivity may be low.

The hydroxyl equivalent of the novolak-type phenolic resin (B) containing an arylene skeleton in the structure is preferably 140 g/eq or more and 210 g/eq or less from the viewpoint of the balance of sensitivity, remaining film rate, resolution, and heat resistance when used as a photoresist composition. and more preferably 150 g/eq or more and 190 g/eq or less, and more preferably 160 g/eq or more and 180 g/eq or less.

One of the preferred embodiments of the novolak-type phenolic resin (B) containing an arylene skeleton in its structure is a novolac-type phenolic resin represented by the following general formula (5) or (6).

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(In Formula (5), R ₂ , a and b are the same as defined in Formula (4). α represents an integer greater than or equal to 0.)

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(In Formula (6), R ₂ , a and b are the same as defined in Formula (4). β represents an integer greater than or equal to 0.)

One of the more preferable aspects of the novolak-type phenolic resin (B) containing an arylene skeleton in its structure is that all a's in the above general formula (5) or (6) are 1 (a=1), and all substituents R ₂ are It is a novolac-type phenol resin represented by the following general formula (5') or (6'), which consists of repeating units that are hydrogen.

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(In formula (5'), α is the same as defined in formula (5).)

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(β in Formula (6') is the same as defined in Formula (6) above.)

The novolak-type phenolic resin (B) containing an arylene skeleton in its structure is a novolak-type phenolic resin represented by the above general formula (5) or (5'), which is used as a phenolic resin composition for photoresists. It is preferable from the viewpoint of handling properties, sensitivity when used as a photoresist composition, remaining film rate, resolution, heat resistance, and balance of etching resistance.

[Method for Producing Novolak-Type Phenolic Resin (B) Containing Arylene Skeleton in Structure]

The novolak-type phenolic resin (B) containing an arylene skeleton in its structure comprises a phenolic compound (b1) represented by the following general formula (7) and a benzene ring or biphenyl ring represented by the following general formula (8) or (9) It can be suitably obtained by subjecting the compound (b2) containing compound (b2) to a condensation reaction without a catalyst or preferably in the presence of an acid catalyst.

<Phenol compound (b1)>

The phenolic compound (b1) used in the manufacture of the novolak-type phenolic resin (B) containing an arylene skeleton in its structure is represented by the following general formula (7).

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(In Formula (7), R ₂ , a and b are the same as defined in Formula (4) above.)

Examples of the phenolic compound represented by the general formula (7) are not particularly limited. Examples of the compound of a=1 include phenol, cresol, ethylphenol, propylphenol, butylphenol, hexylphenol, nonylphenol, xylenol, and butylmethylphenol. Monohydric phenol compounds, such as these, are mentioned. Phenol is especially suitable.

Moreover, as a compound of a=2, dihydric phenols, such as catechol, resorcinol, and hydroquinone, etc. are mentioned suitably. Among them, resorcin is suitable.

Although these phenolic compounds can be used alone or in combination of two or more, it is preferable to use phenol alone from the viewpoint of providing a well-balanced sensitivity, remaining film rate, resolution, and heat resistance when used as a photoresist composition. particularly preferred.

<Compound (b2) Containing Benzene Ring or Biphenyl Ring>

The compound (b2) containing a benzene ring or biphenyl ring used in the production of the novolak-type phenolic resin (B) containing an arylene skeleton in its structure is crosslinked with the phenolic compound (b1) represented by the general formula (7) above. It is a component to do, and is represented by the following general formula (8) or (9).

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(In formula (8) or (9), X represents an alkoxy group or halogen.)

In the compound (b2) containing a benzene ring or biphenyl ring represented by the above general formula (8) or (9), X represents an alkoxy group or halogen.

The alkoxy group is not particularly limited, but an aliphatic alkoxy group having 1 to 6 carbon atoms is preferable. Although a methoxy group and an ethoxy group are mentioned specifically, the methoxy group is preferable from the reactivity with a phenol compound and availability.

As the halogen, a fluorine atom, a chlorine atom, a bromine atom and an iodine atom are exemplified, but a chlorine atom is preferable from the viewpoint of reactivity with phenol compounds and ease of availability.

Examples of compounds containing a benzene ring represented by the general formula (8) include 1,4-di(methoxymethyl)benzene, 1,3-di(methoxymethyl)benzene, and 1,2-di(methoxymethyl). Suitable examples include benzene, 1,4-di(chloromethyl)benzene, 1,3-di(chloromethyl)benzene, and 1,2-di(chloromethyl)benzene. Among them, 1,4-di(methoxymethyl)benzene or 1,4-di(chloromethyl)benzene is preferable from the viewpoints of sensitivity, remaining film rate, resolution, heat resistance and etching resistance when used as a photoresist composition.

Examples of compounds containing a biphenyl ring represented by the general formula (9) include 4,4'-di(methoxymethyl)biphenyl, 2,4'-di(methoxymethyl)biphenyl, and 2,2'- Di(methoxymethyl)biphenyl, 4,4'-di(chloromethyl)biphenyl, 2,4'-di(chloromethyl)biphenyl, 2,2'-di(chloromethyl)biphenyl, etc. can be heard Among them, 4,4'-di(methoxymethyl)biphenyl or 4,4'-di(chloromethyl)biphenyl is preferred from the viewpoint of sensitivity, remaining film rate, resolution, heat resistance and etching resistance when used as a photoresist composition. desirable.

The compounds (b2) containing a benzene ring or biphenyl ring represented by the general formula (8) or (9) can be used singly or in combination of two or more.

Further, as a component for crosslinking the phenolic compound (b1) represented by the general formula (9), together with the compound (b2) containing a benzene ring or a biphenyl ring, formaldehyde is used within a range not interfering with the effect of the present invention. can be used together.

<The molar ratio (b2/b1) of the phenolic compound (b1) and the compound (b2) containing a biphenyl ring or a benzene ring>

In the production of the novolac-type phenolic resin (B) containing an arylene skeleton in its structure, when reacting the phenolic compound (b1) with the compound (b2) containing a benzene ring or biphenyl ring, 1 mole of the phenolic compound (b1) 0.1 to 1.0 mol, more preferably 0.3 to 0.6 mol of the compound (b2) containing a benzene ring or biphenyl ring.

Weight of novolac-type phenolic resin (B) containing an arylene skeleton in the structure used in the present invention by setting the molar ratio of the phenol component (b1) and the compound (b2) containing a biphenyl ring or benzene ring to the above range Average molecular weight (Mw) can be made into a preferable range.

In the preparation of the novolak-type phenolic resin (B) containing an arylene skeleton in its structure, conditions such as <acid catalyst>, <reaction solvent>, <reaction temperature>, <reaction time, reaction pressure> and <post-treatment> For that, it can be manufactured under conventionally known conditions. For example, it can be manufactured under the same conditions as those in the method for producing the novolak-type phenolic resin (A) described above.

[Novolac-type phenolic resin (B) containing a naphthalene skeleton in its structure]

In the novolak-type phenolic resin (B), including a naphthalene skeleton in the structure means that at least one unit of the following general formula (10) is included in the structure.

delete

(In Formula (10), R ₃ is hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 3 to 6 carbon atoms, a phenyl group, a halogen atom, a carboxyl group, an alkoxy group, an acetyl group, a sulfonic acid Represents a sodium group, a nitro group, or an amino group. R ₄ represents hydrogen or a methyl group. c is 1 or more and 3 or less, and when c is 2 or more, each R ₃ may be the same or different. On the other hand, novolak-type phenol When a plurality of units represented by the general formula (10) are included in the structure of the resin (B), a plurality of c, R ₄ and R ₃ contained in the structure of the novolak-type phenolic resin (B) may be the same or different, respectively. )

On the other hand, in the above general formula (10), the hydroxyl group bonded to the naphthalene skeleton, the substituent R ₃ , and the bonded group such as the methylene group are described so that the two benzene rings constituting the naphthalene ring are communicated, the hydroxyl group and the substituent It shows that R _<3> , a methylene group, etc. may couple|bond with any position in the naphthalene ring in which substitution is possible.

In the unit represented by the formula (10), R ₃ represents a substituent bonded to a naphthalene ring having a phenolic hydroxyl group. R ₃ is hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 3 to 6 carbon atoms, a phenyl group, a halogen atom, a carboxyl group, an alkoxy group, an acetyl group, a sodium sulfonate group, a nitro group, or represents an amino group. R ₃ is preferably hydrogen, methyl, ethyl, propyl, butyl, t-butyl, or propyl, more preferably hydrogen or methyl, still more preferably hydrogen. Phenol for photoresists It is preferable from the viewpoint of the balance of the sensitivity, remaining film rate, resolution, heat resistance, and etching resistance when used as a handling property in manufacturing when used as a resin composition and a photoresist composition.

In the unit represented by the general formula (10), c represents the number of substituents R ₃ . c is an integer of 1 or more and 3 or less, and when c is 2 or more, R ₃ may be the same or different. It is preferable that c is 1 from a viewpoint of the balance of sensitivity, remaining film rate, resolution, heat resistance, and etching resistance when used as a phenolic resin composition for photoresists.

Further, when a plurality of units represented by the general formula (10) are included in the structure of the novolak-type phenolic resin (B), a plurality of c and R ₃ contained in the structure of the novolak-type phenolic resin (B) are each the same or It can be different.

In the unit represented by the formula (10), R ₄ represents a substituent bonded to a benzene ring having a phenolic hydroxyl group. R ₄ represents hydrogen or a methyl group. When a plurality of units represented by the general formula (10) are included in the structure of the novolak-type phenolic resin (B), the plurality of R ₄ groups included in the structure of the novolac-type phenolic resin (B) may be the same or different. It is preferable that R ₄ is a methyl group from the viewpoints of manufacturing handling properties when used as a phenolic resin composition for photoresist, and sensitivity, remaining film rate, resolution, heat resistance, and etching resistance when used as a photoresist composition. Further, when R ₄ is a methyl group, the bonding position is preferably para to the phenolic hydroxyl group bonded to the benzene ring.

One of the more preferable aspects of the novolac-type phenolic resin (B) containing a naphthalene skeleton in its structure is a novolak-type phenolic resin represented by the following general formula (11).

delete

(In Formula (11), R ₃ , R ₄ and c have the same definitions as in Formula (10). γ represents an integer greater than or equal to 0.)

One of the more preferable embodiments of the novolak-type phenolic resin (B) having a naphthalene skeleton in its structure is a phenolic resin in which all substituents R ₃ in formula (11) are hydrogen, all substituents R ₄ are methyl groups, and bonded to a benzene ring. It is a novolac-type phenolic resin represented by the following general formula (11'), which consists of a repeating unit bonded to a para-position to a hydroxyl group.

delete

(In Formula (11'), γ is the same as defined in Formula (11) above.)

The weight average molecular weight (Mw) in terms of polystyrene measured by GPC (gel permeation chromatography) of the novolak-type phenolic resin (B) containing a naphthalene backbone in its structure is the manufacturing handling when used as a phenolic resin composition for photoresists 300 to 10000 is preferable, 500 to 8000 is more preferable, 500 to 5000 is still more preferable, 500 to 3000 is even more preferable, and 500 to 1000 is particularly preferable from the viewpoint of performance when used as a photoresist composition or photoresist composition. do. When the weight average molecular weight is smaller than 300, the sensitivity may be too high or the heat resistance may be inferior, and when the weight average molecular weight is larger than 10000, the sensitivity may be low.

The hydroxyl equivalent of the novolac-type phenolic resin (B) containing a naphthalene skeleton in its structure is 130 g/eq or more and 160 g/eq or less from the viewpoint of the balance of sensitivity, remaining film rate, resolution, heat resistance, and etching resistance when used as a photoresist composition. It is preferable, and it is more preferable that it is 140 g/eq or more and 150 g/eq or less.

[Method for Producing Novolak-Type Phenolic Resin (B) Containing Naphthalene Skeleton in Structure]

The novolac-type phenolic resin (B) containing a naphthalene skeleton in its structure is a naphthol compound (c1) represented by the following general formula (12), a phenolic compound (c2) represented by the following general formula (13), and formaldehyde (c3). Preferably, it can be suitably obtained by condensation reaction in the presence of an acid catalyst.

<Naphthol compound (c1)>

The naphthol compound (c1) used in the production of the novolak-type phenolic resin (B) containing a naphthalene skeleton in its structure is represented by the following general formula (12).

delete

(In Formula (12), R ₃ and c are the same as defined in Formula (10).)

Examples of the naphthol compound represented by formula (12) are not particularly limited, but α-naphthol, 1-hydroxy-2-naphthoic acid, 4-methoxy-1-naphthol, 2-acetyl-1-naphthol, Suitable examples include sodium 1-naphthol-4-sulfonate, 4-nitro-1-naphthol, 4-chloro-1-naphthol, 6-amino-1-naphthol, and β-naphthol. Among them, α-naphthol is preferable from the viewpoint of ease of acquisition and performance when used as a photoresist composition.

<Phenol compound (c2)>

The phenolic compound (c2) used in the production of the novolak-type phenolic resin (B) containing a naphthalene skeleton in its structure is represented by the following general formula (13).

delete

(In Formula (13), R ₄ is the same as defined in Formula (10).)

Although there is no limitation in particular as an example of the phenolic compound represented by General formula (13), Phenol, o-cresol, m-cresol, p-cresol, etc. are mentioned suitably. Among them, phenol and para-cresol are preferred from the viewpoint of availability and performance when used as a photoresist composition.

<Formaldehyde (c3)>

The formaldehyde (c3) is not particularly limited, but an aqueous formaldehyde solution may be used, or a polymer that decomposes to formaldehyde in the presence of an acid such as paraformaldehyde or trioxane may be used. Preferably, it is an aqueous formaldehyde solution that is easy to handle, and a commercially available 42% formaldehyde aqueous solution can be suitably used as it is.

<Molar ratio of the phenol component composed of the naphthol compound (c1) and the phenol compound (c2) to formaldehyde (c3) [c3/(c1+c2)]>

When a naphthol compound (c1) or a phenol compound (c2) is reacted with formaldehyde (c3) in the production of a novolak-type phenolic resin (B) containing a naphthalene skeleton in its structure, the naphthol compound (c1) and the phenol compound (c2) The amount of formaldehyde (c3) is preferably 0.1 to 1.0 moles, more preferably 0.3 to 0.6 moles, relative to 1 mole of the phenol component (c1+c2).

The weight average molecular weight (Mw) of the novolac-type phenolic resin (B) containing a naphthol skeleton in the structure used in the present invention can be set to a preferred range by setting the molar ratio of the phenol component (c1+c2) and formaldehyde (c3) within the above range. range can be made.

<Molar ratio (c2/c1) of naphthol compound (c1) to phenolic compound (c2)>

In the production of the novolak-type phenolic resin (B) containing a naphthalene skeleton in its structure, the molar ratio of the naphthol compound (c1) to the phenolic compound (c2) is preferably phenolic compound (c2) with respect to 1 mole of the naphthol compound (c1). is 0.1 to 1.0 mol, more preferably 0.3 to 0.6 mol.

The molar ratio of the naphthol compound (c1) to the phenol compound (c2) within the above range is preferable from the viewpoint of the balance of sensitivity, remaining film rate, resolution, heat resistance and etching resistance when used as a photoresist composition.

Regarding conditions such as <acid catalyst>, <reaction solvent>, <reaction temperature>, <reaction time, reaction pressure> and <post treatment> in the production of the novolak-type phenolic resin (B) containing a naphthalene skeleton in its structure, It can be manufactured according to conventionally well-known conditions. For example, it can be manufactured under the same conditions as those in the method for producing the novolak-type phenolic resin (A) described above.

In the production of the novolac-type phenolic resin (B) containing a naphthalene skeleton in its structure, other production methods include, for example, reacting a phenolic compound (c2) and formaldehyde (c3) under a basic catalyst to obtain a dimethylol form of the phenolic component. A novolac-type phenolic resin (B) can be obtained by a two-step reaction (stepwise method) in which the dimethylol form of the obtained phenol component and the naphthol compound (c1), which is a compound containing a naphthalene skeleton, are reacted in the presence of an acid catalyst. .

Specifically, para-cresol and formaldehyde (c3) as the phenolic compound (c2) are reacted in water under a basic catalyst such as sodium hydroxide at a reaction temperature of 40 to 50° C. for 3 to 6 hours to obtain a phenolic hydroxyl group of para-cresol. A dimethylol compound having a methylol group at two ortho positions is obtained, and then α-naphthol is used as a dimethylol compound of para-cresol and naphthol compound (c1) without a solvent or water, methanol, ethanol, propanol, butanol, toluene, methyl isobutyl In a solvent such as a ketone, under an acid catalyst such as oxalic acid, benzenesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, hydrochloric acid, sulfuric acid or phosphoric acid, the reaction temperature is 40 to 85°C for 2 to 15 hours. As a post-treatment, it is washed with water and thereafter distilled under reduced pressure at 200° C. or less to remove unreacted raw materials to obtain a novolac-type phenolic resin (B).

[Phenolic resin composition for photoresist]

The phenolic resin composition for photoresists of the present invention comprises a novolak-type phenolic resin (A) represented by the above general formula (1) and a novolak-type phenolic resin (B) containing at least one of an arylene skeleton and a naphthalene skeleton in its structure. It is obtained by polymer blending (mixing).

The phenolic resin composition for photoresists of the present invention is obtained by a polymer blend of a novolak-type phenolic resin (A) and a novolak-type phenolic resin (B), the ratio of which is When the total mass of the phenol resin (B) is 100, the mass ratio of the novolak-type phenol resin (A) to the novolak-type phenol resin (B) is 5 to 95:95 to 5, preferably 10 to 90 :90 to 10, more preferably 30 to 90:70 to 10, still more preferably 50 to 90:50 to 10, and particularly preferably 60 to 80:40 to 20.

When the novolak-type phenolic resin (B) has the structure of the above formula (5) or (5'), the mass ratio of the novolak-type phenolic resin (A) to the novolak-type phenolic resin (B) is 60 to 80:40 20 is particularly preferred, and 60 to 70:40 to 30 is most preferred.

Further, when the novolac-type phenolic resin (B) has the structure of the formula (6) or (6'), the mass ratio of the novolak-type phenolic resin (A) to the novolak-type phenolic resin (B) is 60 to 90 :40 to 10 is particularly preferred, and 60 to 80:40 to 20 is most preferred.

If the ratio occupied by the novolac-type phenolic resin (B) is less than 5% by mass, the effect of etching resistance and adhesiveness when used as a photoresist composition becomes small, while, on the other hand, when it exceeds 95% by mass, when used as a photoresist composition The sensitivity may be too high or the heat resistance may be poor, which is undesirable in terms of handling.

The weight average molecular weight (Mw) in terms of polystyrene measured by GPC (Gel Permeation Chromatography) of the phenolic resin composition for photoresists of the present invention is preferably 300 to 10000, and preferably 2000 to 10000 from the performance when used as a photoresist composition. 8000 is more preferable, 3000 to 7000 are more preferable, and 4500 to 6500 are particularly preferable. When the weight average molecular weight is smaller than 300, the sensitivity may be too high or the heat resistance may be inferior, and when the weight average molecular weight is larger than 10000, the sensitivity may be low.

The alkali dissolution rate (DR) of the phenolic resin composition for photoresists of the present invention is preferably 50 to 2000 angstroms/sec, more preferably 100 ~1500 angstroms/second. Even if the alkali dissolution rate is too fast or too slow, the handling property when used as a photoresist composition tends to deteriorate. On the other hand, the alkali dissolution rate in the present specification is the alkali dissolution rate measured by the method described in Examples to be described later.

The softening point (SP) of the phenolic resin composition for photoresists of the present invention is preferably 110 to 200°C, more preferably 130 to 180°C, from the viewpoint of heat resistance and handling.

[Method for Producing Phenolic Resin Composition for Photoresist]

In the method of manufacturing the phenolic resin composition for photoresist of the present invention, as the polymer blending (mixing) method, any method capable of uniformly mixing the novolak-type phenolic resin (A) and the novolak-type phenolic resin (B) is particularly limited It doesn't work. For example, it can be obtained by melt-mixing a novolak-type phenol resin (A) and a novolak-type phenol resin (B).

Specifically, as one production method, a novolak-type phenolic resin (A) is synthesized in advance in a synthesis kiln, and a novolak-type phenolic resin (B) is added thereto, melt-mixed, and post-processed to obtain the composition of the present invention. It is possible to prepare a phenolic resin composition for photoresists. In some cases, a novolak-type phenolic resin (B) is synthesized in advance in a synthesis kiln, and the novolac-type phenolic resin (A) is added thereto, melt-mixed, and then treated to obtain the phenolic resin composition for photoresists of the present invention. may be

In addition, when preparing the photoresist composition, the photoresist composition may be obtained by dissolving each of the novolak-type phenol resins and other additives to be described later in an appropriate solvent.

[Photoresist composition]

The photoresist composition of the present invention contains the phenolic resin composition for photoresists of the present invention and a photosensitizer (E).

As the photosensitizer (E), those known as photosensitizers for photoresists containing novolak-type phenolic resins can be used. As the photosensitizer (E), a quinonediazide compound having a quinonediazide group is preferable, and a 1,2-quinonediazide compound or a derivative thereof is particularly preferable.

By using the quinonediazide compound, the alkali dissolution rate increases in the exposed portion due to the dissolution accelerating effect, and the alkali dissolution rate decreases in the unexposed portion due to the dissolution inhibiting effect. A sharp resist pattern with high contrast can be obtained by the difference in dissolution rate of the negative.

As the quinonediazide compound, known compounds conventionally used in quinonediazide-novolac resists can be used. As such a compound containing a quinonediazide group, a compound obtained by reacting naphthoquinonediazidesulfonic acid chloride or benzoquinonediazidesulfonic acid chloride with a compound having a functional group capable of condensation reaction with these acid chlorides is preferable. Here, a hydroxyl group, an amino group, etc. are mentioned as a functional group capable of a condensation reaction with an acid chloride, and a hydroxyl group is especially suitable. Examples of the compound having a hydroxyl group capable of condensation reaction with acid chloride include hydroquinone, resorcinol, 2,4-dihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 2,4,6- Trihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, Hydroxybenzophenones such as 2,2',3,4,6'-pentahydroxybenzophenone, bis(2,4-dihydroxyphenyl)methane, bis(2,3,4-trihydroxyphenyl) ) Hydroxyphenylalkanes such as methane and bis(2,4-dihydroxyphenyl)propane, 4,4',3",4"-tetrahydroxy-3,5,3',5'-tetramethyl hydroxytriphenylmethanes such as triphenylmethane, 4,4',2",3",4"-pentahydroxy-3,5,3',5'-tetramethyltriphenylmethane; and the like. These compounds can be used individually by 1 type or in combination of 2 or more types.

In addition, specific examples of naphthoquinone diazide sulfonic acid chloride and benzoquinone diazide sulfonic acid chloride, which are acid chlorides, include, for example, 1,2-naphthoquinone diazide-5-sulfonyl chloride, 1,2- Naphthoquinone diazide-4-sulfonyl chloride etc. are mentioned as a preferable thing.

The blending amount of the photosensitizer (E) is preferably 5 to 50 parts by mass, more preferably 10 to 40 parts by mass, based on 100 parts by mass of the phenolic resin composition for photoresists. When the compounding quantity of the photosensitive agent (B) is less than 5 parts by mass, sufficient sensitivity as the photosensitive resin composition may not be obtained, and when it is more than 50 parts by mass, a problem of component precipitation may occur.

In the photoresist composition of the present invention, in addition to the photosensitizer (E), stabilizers such as antioxidants, plasticizers, surfactants, adhesion improvers, dissolution promoters, and dissolution inhibitors, which are common components of photoresist compositions, may be appropriately added.

The phenolic resin composition for photoresists of the present invention and the photoresist composition of the present invention using the same can be suitably used for lithography in manufacturing highly integrated semiconductors or thin film transistor (TFT) materials for liquid crystals.

Example

Hereinafter, the present invention will be described more specifically by examples, but the present invention is not limited to these examples.

[1] Novolak-type phenolic resin (A), novolak-type phenolic resin (B)

The analysis method and evaluation method of the novolac-type phenolic resin are as follows.

(1) Weight average molecular weight (Mw)

GPC measurement was performed under the following conditions, and the weight average molecular weight in terms of polystyrene was determined.

Model: Waters e2695 Waters Co., Ltd. product

Column: 1 x Shodex LF-804

Measurement conditions: column pressure 2.7 MPa

Eluent: tetrahydrofuran (THF)

Flow rate: 1 mL/min

Temperature: 40℃

Detector: UV-Visible Detector 2489

WAVE LENGTH: 254nm

Injection amount: 100 μmL

Sample concentration: 5 mg/mL

(2) Alkali dissolution rate (DR)

3 g of novolak-type phenol resin was dissolved in 9 g of PGMEA (propylene glycol monomethyl ether acetate), and a resin solution was prepared. They were filtered through a 0.2 micro membrane filter. These were applied on a 4-inch silicon wafer with a spin coater to a thickness of about 1.5 μm, and dried on a hot plate at 110° C. for 60 seconds. Subsequently, a developing solution (1.60% tetramethylammonium hydroxide aqueous solution) was used, and the time until the film was completely lost was measured. The value obtained by dividing the initial film thickness by the time until dissolution was taken as the dissolution rate.

(3) Softening point (SP)

The softening point was measured by the ring and ball method based on JIS K6910.

(4) hydroxyl equivalent

It was carried out by hydroxyl equivalent measurement according to JIS K0070.

[Novolak-type phenolic resin (A)]

[Synthesis Example A1] Novolak-type phenolic resin (A1)

75.8 g (0.70 mol) of m-cresol, 113.8 g (1.05 mol) of p-cresol, and 77.71 g (1.09 mol) of 42% formalin were placed in a 1000 ml glass flask equipped with a thermometer, an inlet/outlet port and a stirrer. ), and 0.7 g of oxalic acid were added, reacted at 100°C for 5 hours, and then dehydrated by raising the temperature to 180°C. Thereafter, vacuum distillation was performed at 30 torr for 2 hours to remove unreacted raw materials and the like to obtain 142 g of a meta-para-cresol novolak type phenolic resin (A1).

The obtained meta-para-cresol novolak-type phenolic resin (A1) had a weight average molecular weight of 5900, an alkali dissolution rate of 330 angstroms/second, a softening point of 142°C, and a hydroxyl equivalent of 128 g/eq.

[Synthesis Example A2] Novolak-type phenolic resin (A2)

A meta-para-cresol novolac-type phenolic resin (A2) was obtained in the same manner as in Synthesis Example A1 except that 42% formalin was changed to 75.25 g (1.05 mol). (A2) had a weight average molecular weight of 5000, an alkali dissolution rate of 480 angstroms/second, a softening point of 140°C, and a hydroxyl equivalent of 127 g/eq.

[Synthesis Example A3] Novolak-type phenolic resin (A3)

A meta-para-cresol novolak-type phenolic resin (A3) was obtained in the same manner as in Synthesis Example A1 except that 42% formalin was changed to 83.97 g (1.18 mol). (A3) had a weight average molecular weight of 12000, an alkali dissolution rate of 100 angstroms/second, a softening point of 158°C, and a hydroxyl equivalent of 125 g/eq.

[Synthesis Example A4] Novolak-type phenolic resin (A4)

The meta-para-cresol novolak-type phenolic resin A1 obtained in Synthesis Example A1 was subjected to steam distillation to reduce the dimer component (n = 0).

The obtained meta-para-cresol novolak-type phenolic resin (A4) had a weight average molecular weight of 6300, an alkali dissolution rate of 310 angstroms/second, a softening point of 155°C, and a hydroxyl equivalent of 130 g/eq.

[Synthesis Example A5] Novolak-type phenolic resin (A5)

80.0 g (0.74 mol) of m-cresol, 80.0 g (0.74 mol) of p-cresol, 70.9 g (0.99 mol) of 42% formalin, and 0.6 oxalic acid were placed in a 1000 ml glass flask equipped with a thermometer, an inlet/outlet and a stirrer. g was added, reacted at 100 ° C. for 5 hours, and then the temperature was raised to 180 ° C. to dehydrate. Thereafter, vacuum distillation was performed at 30 torr for 2 hours to remove unreacted raw materials and the like to obtain 144 g of a novolak-type phenolic resin (A5).

The obtained meta-para-cresol novolak-type phenolic resin (A5) had a weight average molecular weight of 12000, an alkali dissolution rate of 170 angstroms/second, a softening point of 162°C, and a hydroxyl equivalent of 123 g/eq.

[Synthesis Example A6] Novolak-type phenolic resin (A6)

94.7 g (0.88 mol) of m-cresol, 142.1 g (1.32 mol) of p-cresol, 26.32 g (0.24 mol) of o-cresol, 42% formalin in a 1000 ml glass flask equipped with a thermometer, inlet/outlet and stirrer 116.6 g (1.63 mol) and 0.92 g of oxalic acid were added, and after reacting at 100°C for 10 hours, the temperature was raised to 180°C and dehydration was performed. Thereafter, vacuum distillation was performed at 30 torr for 2 hours to remove unreacted raw materials and the like to obtain 172 g of a cresol novolac-type phenolic resin (A6).

The obtained novolak-type cresol resin (A6) had a weight average molecular weight of 6200, an alkali dissolution rate of 313 angstroms/second, and a softening point of 141°C.

[Synthesis Example A7] Novolak-type phenolic resin (A7)

31.6 g (0.29 mol) of m-cresol, 126.5 g (1.17 mol) of p-cresol, 17.9 g (0.16 mol) of resorcin, and 69.74 42% formalin were placed in a 1000 ml glass flask equipped with a thermometer, an inlet/outlet and a stirrer. g (0.98 mol) and 1.8 g of oxalic acid were added, reacted at 100°C for 5 hours, and then the temperature was raised to 180°C for dehydration. Thereafter, vacuum distillation was performed at 30 torr for 2 hours to remove unreacted raw materials and the like to obtain 141 g of a novolak-type phenolic resin (A7).

The obtained novolak-type cresol resin (A7) had a weight average molecular weight of 9000, an alkali dissolution rate of 668 angstroms/second, and a softening point of 153°C.

[Novolak-type phenolic resin (B)]

Novolak type phenolic resin (B1)

A novolac-type phenolic resin (weight average molecular weight: 1200, alkali dissolution rate: 4861 angstroms/second, softening point: 65°C, hydroxyl equivalent: 175 g), which contains a benzene ring in the structure as an arylene skeleton, represented by the following general formula (14) /eq).

delete

(In formula (14), α represents an integer greater than or equal to 0.)

Novolak type phenolic resin (B2)

A novolac-type phenolic resin (weight average molecular weight: 4500, alkali dissolution rate: 63 angstroms/second, softening point: 86°C, hydroxyl equivalent: 178 g /eq).

Novolak type phenolic resin (B3)

A novolac-type phenolic resin (weight average molecular weight: 1070, alkali dissolution rate: 828 angstroms/sec, softening point: 66°C, hydroxyl equivalent: 203g/eq).

delete

(In formula (15), β represents an integer greater than or equal to 0.)

Novolak type phenolic resin (B4)

A novolac-type phenolic resin (weight average molecular weight: 1400, alkali dissolution rate: 95 angstroms/sec, softening point: 73°C, hydroxyl equivalent: 206g/eq).

Novolak type phenolic resin (B5)

A novolak-type phenolic resin (weight average molecular weight: 730, alkali dissolution rate: 5768 angstroms/sec, softening point: 114, hydroxyl equivalent: 143 g/ eq).

delete

(In formula (16), γ represents an integer greater than or equal to 0.)

Table 1 summarizes the novolak-type phenol resin (A) and the novolak-type phenol resin (B).

[2] Phenolic resin composition for photoresist, photoresist composition

Next, examples of the phenolic resin composition for photoresists of the present invention and photoresist compositions using the same are shown.

On the other hand, the phenol resin composition for photoresist and the analysis method or evaluation method of the photoresist composition are as follows.

<Phenolic resin composition for photoresist>

(1) weight average molecular weight (Mw), (2) alkali dissolution rate (DR), and (3) softening point (SP) were evaluated by the same method as the analysis method and evaluation method of the novolak-type phenolic resin described above. .

<Photoresist composition>

(1) Sensitivity, remaining film rate, and resolution

The photoresist composition was applied on a 4-inch silicon wafer by a spin coater and dried on a hot plate at 110 DEG C for 60 seconds to form a coating film with a thickness of 15000 angstroms. Thereafter, using a reduction projection exposure apparatus, the exposure time was changed step by step to confirm the optimum exposure amount, and then exposure was performed to achieve the optimum exposure amount. Then, using a developing solution (2.38% tetramethylammonium hydroxide aqueous solution), it was developed for 60 seconds, rinsed, and dried.

Sensitivity

The sensitivity was evaluated according to the following criteria by observing the pattern shape of the obtained pattern with a scanning electron microscope.

AA: An image can be formed at less than 3 mJ/cm 2 .

A: Images can be formed at less than 5 mJ/cm 2 .

B: An image can be formed at 5 to 60 mJ/cm 2 .

remaining film rate

The remaining film rate was determined from the remaining film thickness of the unexposed area. The residual film rate is ratio of the film thickness of the photosensitive resin after development and the film thickness of the photosensitive resin before development, and is a value represented by the following formula.

Film remaining rate (%) = (film thickness of photosensitive resin after development / film thickness of photosensitive resin before development) × 100

resolution

The resolution was evaluated according to the following criteria using a test chart mask.

◎: 1.5 μ line & space can be resolved.

○: 2.0 μ line & space can be resolved.

×: 2.0 μ line & space cannot be resolved.

(2) Dry etching resistance

The resist film obtained with the positive pattern was dry etched using an etching apparatus under etching conditions of 0.7 sccm and 80 W using CF ₄ as an etching gas, and the film thickness before and after etching was measured to etch the resist pattern. I saved the rate. The results were compared with the etching rate in the case of using only the novolac-type phenolic resin (A) as a phenolic resin composition for photoresists.

Ratio of the etching rate of the novolac-type phenolic resin composition for photoresist and the etching rate in the case of only the novolak-type phenolic resin (A) used in the novolak-type phenolic resin composition for photoresist ([Novolak-type phenolic resin for photoresist Etching rate]/[Etching rate in the case of only novolac-type phenolic resin (A)]) was evaluated according to the following criteria.

◎: When less than 0.75

○: In the case of 0.75 or more and 0.90 or less

×: When exceeding 0.90

[Example 1]

A novolac-type phenolic resin (A2) obtained in Synthesis Example A2 and a novolak-type phenolic resin (B1) obtained in Synthesis Example B1 were melt-mixed to prepare a photoresist phenolic resin composition. Specifically, 70 g of a novolak-type phenolic resin (A2) and 30 g of a novolak-type phenolic resin (B1) were mixed in a 500 ml glass flask equipped with a thermometer, an inlet/outlet port and a stirrer in the formulation shown in Table 2 below, It melt-mixed under the temperature condition of 185 degreeC, and prepared the phenolic resin composition for photoresists.

The obtained phenolic resin composition for photoresists had a weight average molecular weight of 3300, an alkali dissolution rate of 1210 angstroms/second, and a softening point of 139°C.

Table 2 shows the results of evaluating the characteristics of this phenolic resin composition for photoresists.

Next, a photoresist composition was prepared using the obtained phenol resin composition for photoresists. Specifically, 20 g of a phenolic resin composition for photoresist and 5 g of 1,2-naphthoquinonediazide-5-sulfonyl chloride were dissolved in 75 g of PGMEA (propylene glycol monomethyl ether acetate), and filtered through a 0.2 micro membrane filter. Thus, a photoresist composition was obtained.

Table 2 shows the results of evaluating the properties of this photoresist composition.

[Examples 2 to 10, Comparative Examples 1 to 12]

The novolak-type phenolic resins (A1) to (A7) and the novolak-type phenolic resins (B1) to (B5) obtained in Synthesis Example were melt-mixed by the same method as in Example 1 according to the formulation shown in Table 2 below. A phenolic resin composition for photoresist was obtained.

Table 2 shows the results of evaluating the characteristics of the obtained phenolic resin composition for photoresists.

Next, a photoresist composition was obtained in the same manner as in Example 1 using the obtained phenolic resin composition for photoresists.

Table 2 shows the results of evaluating the characteristics of the obtained photoresist composition.

As is evident from the results shown in Table 2, the photoresist compositions obtained in each Example have high developability such as high sensitivity, high remaining film rate and high resolution, and are also excellent in etching resistance.

For example, from the comparison between Example 2 and Comparative Example 3, the resist composition using the phenolic resin composition for photoresist of Example 2 is superior to the case of using the novolac-type phenolic resin A3 of Comparative Example 3 alone, It turns out that dry etching property is improved.

Further, from the comparison between Example 2 and Comparative Example 8, it is found that the resist composition of Example 2 has an improved film remaining rate compared to that of Comparative Example 8.

In addition, from the comparison between Example 2 and Comparative Example 3 and Comparative Example 8, the resolution of the resist composition of Example 2 is the resolution of Example 2, although the resolution of Comparative Example 3 is ○ and the resolution of Comparative Example 8 is ×. It can be seen that is improved to ◎.

Claims (4)

A novolak-type phenolic resin (A) represented by the following general formula (1) and a novolak-type phenolic resin (B) containing at least one of an arylene skeleton and a naphthalene skeleton in the structure, the mass ratio of (A) and (B) A phenolic resin composition for photoresist comprising an amount of 5 to 95:95 to 5,
The arylene skeleton is a unit represented by the following general formula (4), characterized in that, a phenolic resin composition for photoresists.

(In general formula (1), R ₁ represents hydrogen or a linear or branched alkyl group having 1 to 8 carbon atoms, which may be the same or different. However, at least one of R ₁ has 1 to 8 carbon atoms. is a linear or branched alkyl group of , p is 1 or more and 3 or less, which may be the same or different, q is 1 or more and 3 or less, which may be the same or different, provided that p+q≤4, n is 0 Indicates an integer above.)

(In general formula (4), X represents a divalent group represented by the following formula (4-1) or (4-2).

R ₂ represents hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 3 to 6 carbon atoms, a phenyl group, or a halogen. a is 1 or 2; b is 1 or more and 3 or less, and when b is 2 or more, R ₂ may be the same or different. However, a+b≤4. On the other hand, when a plurality of units represented by the general formula (4) are included in the structure of the novolac-type phenolic resin (B), a plurality of a, b and R ₂ contained in the structure of the novolak-type phenolic resin (B) are respectively may be the same or different.) According to claim 1,
A phenolic resin composition for photoresists, wherein the novolak-type phenolic resin (B) contains in its structure a unit represented by the general formula (4). According to claim 1,
A phenolic resin composition for photoresists, wherein the novolak-type phenolic resin (B) contains in its structure a unit represented by the following general formula (10).

(In Formula (10), R ₃ is hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 3 to 6 carbon atoms, a phenyl group, a halogen atom, a carboxyl group, an alkoxy group, an acetyl group, a sulfonic acid Represents a sodium group, a nitro group, or an amino group. R ₄ represents hydrogen or a methyl group. c is 1 or more and 3 or less, and when c is 2 or more, each R ₃ may be the same or different. On the other hand, novolak-type phenol When a plurality of units represented by the general formula (10) are included in the structure of the resin (B), a plurality of c, R ₄ and R ₃ contained in the structure of the novolak-type phenolic resin (B) may be the same or different, respectively. ) A photoresist composition comprising the phenolic resin composition for photoresist according to any one of claims 1 to 3 and a photosensitizer.