JPWO2019050047A1 - Phenolic resin composition for photoresist and photoresist composition - Google Patents

Abstract

The mass of the novolak-type phenolic resin (A) represented by the general formula (1) and the novolac-type phenolic resin (B) containing at least one of an arylene skeleton and a naphthalene skeleton in the structure (A) and (B). A phenolic resin composition for a photoresist, which comprises an amount having a ratio of 5 to 95: 95 to 5. [Chemical formula 1] (In the general formula (1), R1 represents hydrogen or a linear or branched alkyl group having 1 to 8 carbon atoms, which may be the same or different, respectively. At least one of the above is a linear or branched alkyl group having 1 or more and 8 or less carbon atoms. P is 1 or more and 3 or less, and they may be the same or different. Q is 1 or more and 3 The following are the same or different, respectively. However, p + q ≦ 4. n represents an integer of 0 or more.)

Description

The present invention relates to a phenolic resin composition for a photoresist and a photoresist composition containing a phenolic resin composition for a photoresist.

In recent years, the line width of circuit patterns of integrated circuit semiconductors has been steadily miniaturized as the degree of integration has increased. Further, the line width of a liquid crystal display element or the like is also narrowed and tends to be miniaturized. As display panels become larger and lower in cost, there is a need for technology that enables stable wiring formation on large substrates in a simple process.
Further, among the photolithography techniques conventionally used in the semiconductor field, a process of patterning a resist film and then forming wiring by a wet etching method or a dry etching method is widespread, and the technique is used as a liquid crystal display element. There is a trend that it is also applied in the manufacturing process of.
Along with this, the required performance for photoresist resin materials has become more sophisticated and diversified, and it has excellent high developability such as high sensitivity, high residual film ratio, and high resolution, and etching resistance such as wet etching resistance and dry etching resistance. Must be.

Examples of the phenolic resin most widely used for photoresist applications include cresol novolac type phenolic resin (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2-55359

However, the cresol novolac type phenolic resin as described in Patent Document 1 cannot meet the above-mentioned advanced and diversified market demand performance in recent years, and its etching resistance is not sufficient.

Therefore, an object of the present invention is to provide a phenolic resin composition for a photoresist and a photoresist composition, which have high developability such as high sensitivity, high residual film ratio, and high resolution, and are also excellent in etching resistance. ..

As a result of diligent studies to solve the above problems, the present inventors have made a novolak-type phenol resin (A) represented by a specific general formula and a novolak-type phenol containing a specific structure of an arylene skeleton or a naphthalene skeleton in the resin skeleton. A photoresist composition using a phenolic resin composition for a photoresist obtained by polymer-blending the resin (B) is excellent in developability such as high sensitivity, high residual film ratio, and high resolution, and also excellent in etching resistance. This led to the present invention.

That is, the present invention relates to the following matters.
1. 1. The novolac-type phenolic resin (A) represented by the following general formula (1) and the novolac-type phenolic resin (B) containing at least one of an arylene skeleton and a naphthalene skeleton in the structure are referred to as (A) and (B). The present invention relates to a phenolic resin composition for a photoresist containing an amount having a mass ratio of 5 to 95: 95 to 5.

(In the general formula (1), R ₁ represents hydrogen or a linear or branched alkyl group having 1 or more and 8 or less carbon atoms, which may be the same or different from each other, but at least R ₁ . One is a linear or branched alkyl group having 1 or more and 8 or less carbon atoms. P is 1 or more and 3 or less, and they may be the same or different. Q is 1 or more and 3 or less. Yes, they may be the same or different, respectively. However, p + q ≦ 4. n represents an integer of 0 or more.)

2. The above 1. The novolak type phenol resin (B) contains a unit represented by the following general formula (4) in its structure. The present invention relates to the phenolic resin composition for photoresist.

(In the 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. When b is 1 or more and 3 or less and b is 2 or more, R ₂ may be the same or different, respectively. However, a + b ≦ 4. When a plurality of units represented by the general formula (4) are contained in the structure of the novolak type phenol resin (B), the plurality of a, b and R ₂ contained in the structure of the novolak type phenol resin (B) are present. , Each may be the same or different. )

3. 3. The above 1. The novolak type phenol resin (B) contains a unit represented by the following general formula (10) in its structure. The present invention relates to the phenolic resin composition for photoresist.

(In the general 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, and the like. Represents an alkoxy group, an acetyl group, a sodium sulfonate group, a nitro group, or an amino group. R ₄ represents a hydrogen or methyl group. C is 1 or more and 3 or less, and when c is 2 or more, R ₃ may be the same or different from each other. When a plurality of units represented by the general formula (10) are included in the structure of the novolak type phenol resin (B), the structure of the novolak type phenol resin (B) includes a plurality of units. The plurality of c, R ₄ and R ₃ included may be the same or different, respectively.)

4. The above 1. To 3. The present invention relates to a photoresist composition containing any of the above-mentioned phenolic resin compositions for photoresists and a photosensitive agent.

According to the present invention, it is possible to provide a phenolic resin composition for a photoresist and a photoresist composition, which have high developability such as high sensitivity, high residual film ratio, and high resolution, and are also excellent in etching resistance.

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

(In the general formula (1), R ₁ represents hydrogen or a linear or branched alkyl group having 1 or more and 8 or less carbon atoms, which may be the same or different from each other, but at least R ₁ . One is a linear or branched alkyl group having 1 or more and 8 or less carbon atoms. P is 1 or more and 3 or less, and they may be the same or different. Q is 1 or more and 3 or less. Yes, they may be the same or different, respectively. However, p + q ≦ 4. n represents an integer of 0 or more.)

The phenolic resin composition for a photoresist of the present invention contains both the novolak-type phenol resin (A) and the novolak-type phenol resin (B) to obtain a photoresist composition with high sensitivity and high residual content. Both the developability such as film ratio and high resolution and the etching resistance such as wet etching resistance and dry etching resistance are excellent.

[Novolak type phenol resin (A)]
In the phenolic resin composition for photoresist of the present invention, the novolak type phenolic resin (A) is represented by the general formula (1).

In the novolak type phenol resin (A) represented by the general formula (1), R ₁ represents a substituent bonded to a benzene ring having a phenolic hydroxyl group. R ₁ is hydrogen, or represents a number 1 to 8 linear or branched alkyl group having a carbon plurality of R ₁ contained in the structure of the novolak phenolic resin (A) are the same or different May be. However, at least one of R _{1 is} a linear or branched alkyl group having 1 to 8 carbon atoms. That is, novolak phenolic resin (A) has exactly the alkyl-substituted phenol skeleton in which an alkyl group is bonded as a substituent R ₁ on the benzene ring having a phenolic hydroxyl group. R ₁ is preferably a hydrogen, methyl group, ethyl group, propyl group, butyl group, t-butyl group, propyl group, vinyl group or octyl group. From the viewpoints of sensitivity, residual film ratio, resolution, and heat resistance when the phenolic resin composition for photoresist is used, R ₁ is more preferably a methyl group.

In novolak phenolic resin (A) represented by the general formula (1), q represents the number of the substituent R _1. q is an integer of 1 or more and 3 or less, and may be the same or different from each other. Here, "may be the same or different" in q means that a plurality of qs contained in the structure of the novolak type phenol resin (A) may be the same or different, respectively. From the viewpoint of the balance of sensitivity, residual film ratio, resolution, and heat resistance of the phenolic resin composition for photoresist, q is preferably 1 in all.

In the novolak 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 from each other. Here, "may be the same or different" in p means that a plurality of ps contained in the structure of the novolak type phenol resin (A) may be the same or different, respectively. However, the sum p + q of the number q of the substituents R ₁ mentioned above is 4 or less. From the viewpoint of the balance between sensitivity, residual film ratio, resolution, and heat resistance when the phenolic resin composition for photoresist is used, it is preferable that p is all 1. If the number of phenolic hydroxyl groups is large, the dissolution rate in alkali becomes too high, and the photoresist composition may have poor handleability.

In the novolak type phenol resin (A) represented by the general formula (1), n represents the number of repetitions and is an integer of 0 or more.

Since the novolak-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 a value such that the polystyrene-equivalent weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) of the novolak type phenol resin (A) is 1000 to 50,000. It is more preferably a value of 1500 to 30000, further preferably a value of 1500 to 25000, and particularly preferably a value of 3000 to 15000, and 5000 to 12000. Most preferably, the value is such that

The novolak type phenol resin (A) represented by the general formula (1) has a polystyrene-equivalent weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) within the above range. It is preferable from the viewpoints of manufacturing handleability when it is made into a phenolic resin composition for use, sensitivity, residual film ratio, resolution, and heat resistance when it is made into a photoresist composition. If the weight average molecular weight is less than 1000, the sensitivity may be too high or the heat resistance may be inferior, and if it is larger than 50,000, the sensitivity may be low.

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

Further, in the novolak type phenol resin (A) represented by the general formula (1), one of the more preferable embodiments is that all p and q of the general formula (1) are 1 (p = 1, q = 1). It is a cresol novolak resin represented by the following general formula (2), wherein all the substituents R are methyl groups.

(In the general formula (2), n is the same as the definition in the general formula (1).)

By using the cresol novolak resin represented by the general formula (2) as the novolak type phenol resin (A), a photoresist composition having a good balance of sensitivity, residual film ratio, resolution and heat resistance can be obtained. Therefore, it is preferable.

In the novolak-type phenolic resin (A), which is one of the preferred embodiments represented by the general formula (2), the methyl group is located at any of the ortho, meta, or para-position substitution positions with respect to the phenolic hydroxyl group. You may. From the viewpoint of providing a good balance of sensitivity, residual film ratio, resolution, and heat resistance when used as a photoresist composition, a phenolic skeleton in which a methyl group is substituted at the meta position with respect to a phenolic hydroxyl group and methyl at the para position. It is preferable that the structure has a phenol skeleton to which a group is bonded. The novolak-type phenolic resin (A) is more preferably composed of a phenolic skeleton in which a methyl group is substituted at the meta position with respect to the phenolic hydroxyl group and a phenolic skeleton in which a methyl group is bonded at the para position. The molar ratio of meta-position: para-position can be adjusted by adjusting the molar ratio of the phenol compound (a1) at the time of charging the raw material, which will 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 at the para position are the molar ratios of the meta position: para position when the raw materials are prepared. Is preferably an amount of 20 to 80:80 to 20, more preferably 30 to 70:70 to 30, and even more preferably 40 to 60:60 to 40. , 40 to 50:60 to 50, which is particularly preferable.
The position of the methyl group in the phenolic skeleton in the structure of the novolak-type phenolic resin (A) affects the etching resistance and alkali solubility of the resist composition. By increasing the number of phenol skeletons in which a methyl group is bonded to the para position, a photoresist composition having high etching resistance can be obtained. The ratio of the para position is preferably more than 50%. When the ratio of the meta position is large, there is a possibility that the alkali dissolution rate becomes high and the residual film ratio decreases. If the ratio of meta position is up to 50%, there is no risk.

[Manufacturing method of novolak type phenol resin (A)]
The novolak-type phenolic resin (A) represented by the general formula (1) is obtained by subjecting a phenol compound (a1) represented by the following general formula (3) and formaldehyde (a2) to a polycondensation reaction under an acidic catalyst. Obtainable.

<Phenol compound (a1)>
The phenol compound (a1) used in the production of the novolak type phenol resin (A) is represented by the following general formula (3).

(In the general formula _{(3), R} 1, p and q are the same as defined in the general formula (1).)

Examples of the phenol compound represented by the general formula (3) are not particularly limited, but examples of the compound having p = 1 include phenol, m-cresol, p-cresol, o-cresol, 2,3-xylenol, and 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 and the like can be mentioned.
Examples of the compound having p = 2 include catechol, resorcin, hydroquinone and the like. Of these, resorcin is preferred.
Examples of the P = 3 compound include hydroxyquinol, fluoroglycinol, pyrogallol and the like.
These phenol compounds may be used alone or in combination of two or more. However, an alkyl-substituted phenol 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, from the viewpoint of providing a well-balanced sensitivity, residual film ratio, resolution, and heat resistance when the photoresist composition is prepared, m-cresol, p-cresol, and o-cresol cresols are used as the phenol compound (a1). It is preferable to use it, it is more preferable to use m-cresol and p-cresol, and it is further preferable to use m-cresol and p-cresol in combination.
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, preferably 30 to 70:70 to 30. It is more preferable that the amount is 40 to 60:60 to 40, and it is particularly preferable that the amount is 40 to 50:60 to 50.

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

<Mole ratio (a2 / a1) of phenol compound (a1) and formaldehyde (a2)>
In the production of the novolak-type phenolic resin (A), when the phenolic compound (a1) and the formaldehyde (a2) are reacted, formaldehyde (a2) is preferably used with respect to 1 mol of the phenolic compound (a1). It is 2 to 1.0 mol, more preferably 0.5 to 0.9 mol.
By setting the molar ratio of the phenol compound (a1) to formaldehyde (a2) in the above range, the weight average molecular weight (Mw) of the novolak type phenol resin (A) used in the present invention can be set in a preferable range. ..

<Acid catalyst>
The reaction conditions of the polycondensation reaction in the production of the novolak type phenol resin (A) of the present invention may be the conventionally known reaction conditions applied when preparing a normal phenol resin. That is, the acid catalyst used is not particularly limited as long as it is an acid capable of reacting the phenol component and the formaldehyde component, and for example, oxalic acid, benzenesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid and the like. Inorganic acids such as organic sulfonic acid, hydrochloric acid, and sulfuric acid can be used alone or in combination of two or more. Of these, sulfuric acid, oxalic acid or p-toluenesulfonic acid is particularly preferable.

The amount of the acid catalyst used is about 0.01 to 1% by mass with respect to the phenol component (a1). When the novolak type phenol resin (A) is used in the composition for photoresist, the acid catalyst remaining in the resin may affect the characteristics of the photoresist, so it is preferable that the amount is as small as possible. The preferred amount to be used depends on the type, 0.3 to 1.0% by mass for oxalic acid, 0.05 to 0.1% by mass for sulfuric acid, and 0.1 for p-toluenesulfonic acid. It is recommended to use about 0.5% by mass.

<Reaction solvent>
As the reaction solvent, water contained in the raw material formaldehyde can play the role of a solvent, but in addition to water, an organic solvent that does not affect the reaction can also be used if 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; and cyclic ethers such as tetrahydrofuran and dioxane. Be done.
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. If it is lower than 50 ° C., the reaction will not proceed easily, and if it exceeds 200 ° C., it will be difficult to control the reaction, and it will be difficult to stably obtain the target novolak type phenol resin (A).

<Reaction time, reaction pressure>
The reaction time of the polycondensation reaction depends on the reaction temperature, but is usually about 0.1 to 20 hours. The reaction pressure of the polycondensation reaction is usually carried out under normal pressure, but may be carried out under pressure or reduced pressure.

<Post-processing>
As the post-treatment after the completion of the polycondensation reaction, it is preferable to add a base to neutralize the acid catalyst in order to completely stop the reaction, and then add water to remove the acid catalyst and perform washing with water. ..

The base for neutralizing the acid catalyst is not particularly limited, and any base that neutralizes the acid catalyst and forms a salt that is soluble in water can be used. Examples thereof include 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 hydrogen carbonate, calcium carbonate and the like. Specific examples of the amine of the organic base or the organic amine include ammonia, trimethylamine, triethylamine, diethylamine, tributylamine and the like. Preferably, an organic amine is used. The amount used depends on the amount of the acid catalyst, but it is preferable to neutralize the acid catalyst and use the amount so that the pH in the reaction system falls within the range of 4 to 8.

The amount of water used for washing and the number of washings are not particularly limited, but from an economic point of view, in order to remove the acid catalyst to an amount that does not affect the actual use, the number of washings is about 1 to 5 times. preferable. The temperature of washing with water is not particularly limited, but is preferably 40 to 95 ° C. from the viewpoint of efficiency and workability of removing catalyst species. When the separation between the novolak type phenol resin (A) and the washing water is poor during washing with water, it is effective to add a solvent or raise the temperature of washing with water in order to reduce the viscosity of the mixed solution. The solvent type is not particularly limited, but 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 a reduced pressure of 20 to 50 torr, volatile components such as unreacted raw materials and organic solvents remaining in the reaction mixture. By distilling off the desired novolak type phenol resin (A), the desired novolak type phenol resin (A) can be suitably separated and recovered.

[Novolak type phenol resin (B)]
In the phenolic resin composition for photoresist of the present invention, the novolak type phenolic resin (B) contains at least one of an arylene skeleton and a naphthalene skeleton in the structure. The phenolic resin composition for a photoresist of the present invention contains the novolak type phenolic resin (B), so that when it is used as a photoresist composition, it has high sensitivity, high residual film ratio, high resolution and other developability, and is wet. Both etching resistance such as etching resistance and dry etching resistance are excellent.

[Novolac type phenolic resin (B) containing an arylene skeleton in its structure]
In the novolak type phenol resin (B), the inclusion of an arylene skeleton in the structure means that at least one unit (constituent unit) of the following general formula (4) is included in the structure.

(In the 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. When b is 1 or more and 3 or less and b is 2 or more, R ₂ may be the same or different, respectively. However, a + b ≦ 4. When a plurality of units represented by the general formula (4) are contained in the structure of the novolak type phenol resin (B), the plurality of a, b and R ₂ contained in the structure of the novolak type phenol resin (B) are present. , Each 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 a halogen. R ₂ is preferably hydrogen, methyl, ethyl, propyl, butyl, t- butyl group, a propyl group, more preferably a hydrogen or a methyl group, is even more preferably hydrogen , It is preferable from the viewpoint of the handling property in production when the phenolic resin composition for a photoresist is prepared, and the balance between the sensitivity, the residual film ratio, the resolution, the heat resistance, and the etching resistance when the photoresist composition is prepared.

In the unit represented by the general formula (4), b represents the number of the substituent 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, respectively. From the viewpoint of the balance of sensitivity, residual film ratio, resolution, heat resistance, and etching resistance of the phenolic resin composition for photoresist, b is preferably 1.

Further, when a plurality of units represented by the general formula (4) are contained in the structure of the novolak type phenol resin (B), the plurality of b and R ₂ contained in the structure of the novolak type phenol resin (B) are each contained. It may be the same or 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 a + b of the number b of the substituents R ₂ of the above is 4 or less. From the viewpoint of the balance of sensitivity, residual film ratio, resolution, heat resistance, and etching resistance of the phenolic resin composition for photoresist, a is preferably 1.
Further, when a plurality of units represented by the general formula (4) are contained in the structure of the novolak type phenol resin (B), the plurality of a contained in the structure of the novolak type phenol resin (B) are the same or different from each other. You may be. That is, the novolak type phenol resin (B) may contain a skeleton of monovalent phenol (a = 1) and a skeleton of divalent phenol (a = 2) in the same structure.

The polystyrene-equivalent weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) of a novolak-type phenolic resin (B) containing an arylene skeleton in its structure is used in the production of a phenolic resin composition for photoresist. From the viewpoint of handleability and performance of the photoresist composition, 300 to 10000 is preferable, 500 to 8000 is more preferable, 500 to 5000 is further preferable, 1000 to 1500 is particularly preferable, and 1200 to 1400 is extremely preferable. If the weight average molecular weight is less than 300, the sensitivity may be too high or the heat resistance may be inferior, and if it is more than 10,000, the sensitivity may be low.

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

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

(In the general formula (5), R ₂ , a and b are the same as the definitions in the general formula (4). Α represents an integer of 0 or more.)

(In the general formula _{(6), R} 2, a and b are the same as defined above, and defined in the general formula (4) .Beta represents an integer of 0 or more.)

One of the more preferable embodiments of the novolak-type phenolic resin (B) containing an arylene skeleton in its structure is that all a of the above general formula (5) or (6) are 1 (a = 1) and all substitutions are made. composed of a repeating unit group R ₂ is hydrogen, a novolak type phenolic resin represented by the following general formula (5 ') or (6').

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

(In the general formula (6'), β is the same as the definition in the general formula (6).)

When the novolak-type phenol resin (B) containing an arylene skeleton in its structure is a novolak-type phenol resin represented by the general formula (5) or (5'), the phenol resin composition for photoresist is used. It is preferable from the viewpoint of the handling property in manufacturing, the sensitivity when the photoresist composition is obtained, the residual film ratio, the resolution, the heat resistance, and the etching resistance.

[Method for producing novolac-type phenolic resin (B) containing an arylene skeleton in its structure]
The novolak-type phenol resin (B) containing an arylene skeleton in its structure comprises a phenol 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 preferably obtained by subjecting the compound (b2) containing the compound (b2) to a condensation reaction in the presence of a non-catalyst or preferably an acid catalyst.

<Phenol compound (b1)>
The phenol compound (b1) used in the production of the novolak type phenol resin (B) containing an arylene skeleton in its structure is represented by the following general formula (7).

(In the general formula _{(7), R} 2, a and b are the same as defined in the general formula (4).)

Examples of the phenol compound represented by the general formula (7) are not particularly limited, but examples of the compound with a = 1 include phenol, cresol, ethylphenol, propylphenol, butylphenol, hexylphenol, nonylphenol, xylenol, and butylmethyl. Examples thereof include monovalent phenol compounds such as phenol. Of these, phenol is preferable.
Moreover, as a compound of a = 2, a divalent phenol such as catechol, resorcin, hydroquinone and the like can be preferably mentioned. Of these, resorcin is preferred.
One of these phenol compounds can be used alone or in combination of two or more, but from the viewpoint of providing a good balance of sensitivity, residual film ratio, resolution, and heat resistance when prepared as a photoresist composition. It is particularly preferred to use phenol alone.

<Compound containing a benzene ring or a biphenyl ring (b2)>
The compound (b2) containing a benzene ring or a biphenyl ring used in the production of a novolak-type phenol resin (B) containing an arylene skeleton in its structure crosslinks the phenol compound (b1) represented by the general formula (7). It is a component to be used and is represented by the following general formula (8) or (9).

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

In the compound (b2) containing a benzene ring or a biphenyl ring represented by the general formula (8) or (9), X represents an alkoxy group or a halogen.
The alkoxyl group is not particularly limited, but an aliphatic alkoxy group having 1 to 6 carbon atoms is preferable. Specific examples thereof include a methoxy group and an ethoxy group, but a methoxy group is preferable from the viewpoint of reactivity with a phenol compound and availability.
Examples of the halogen include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and the chlorine atom is preferable from the viewpoint of reactivity with a phenol compound and easy availability.

Examples of the compound 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) benzene. Preferable examples thereof include 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 selected from the viewpoints of sensitivity, residual film ratio, resolution, heat resistance, and etching resistance when used as a photoresist composition. preferable.

Examples of the compound 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 and the like can be preferably mentioned. Above all, from the viewpoint of sensitivity, residual film ratio, resolution, heat resistance, and etching resistance when used as a photoresist composition, 4,4'-di (methoxymethyl) biphenyl or 4,4'-di (chloromethyl). Biphenyl is preferred.

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

Further, as a component for cross-linking the phenol compound (b1) represented by the general formula (9), formaldehyde is used together with the compound (b2) containing a benzene ring or a biphenyl ring as long as the effect of the present invention is not impaired. Can be used.

<Mole ratio (b2 / b1) of the phenol compound (b1) to the compound (b2) containing a biphenyl ring or a benzene ring>
In the production of a novolak-type phenolic resin (B) containing an arylene skeleton in its structure, when the phenol compound (b1) is reacted with the compound (b2) containing a benzene ring or a biphenyl ring, 1 mol of the phenol compound (b1) is produced. On the other hand, the compound (b2) containing a benzene ring or a biphenyl ring is preferably 0.1 to 1.0 mol, more preferably 0.3 to 0.6 mol.
By setting the molar ratio of the phenol component (b1) to the compound (b2) containing a biphenyl ring or a benzene ring within the above range, the novolac-type phenol resin (B) containing the arylene skeleton used in the present invention in its structure The weight average molecular weight (Mw) can be in a preferable range.

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

[Novolak type phenolic resin (B) containing a naphthalene skeleton in its structure]
In the novolak type phenol resin (B), the inclusion of a naphthalene skeleton in the structure means that at least one unit of the following general formula (10) is included in the structure.

(In the general 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, and the like. Represents an alkoxy group, an acetyl group, a sodium sulfonate group, a nitro group, or an amino group. R ₄ represents a hydrogen or methyl group. C is 1 or more and 3 or less, and when c is 2 or more, R ₃ may be the same or different from each other. When a plurality of units represented by the general formula (10) are included in the structure of the novolak type phenol resin (B), the structure of the novolak type phenol resin (B) includes a plurality of units. The plurality of c, R ₄ and R ₃ included may be the same or different, respectively.)

Incidentally, in the general formula (10), the hydroxyl groups bonded to the naphthalene skeleton, a bond such as a substituent R ₃ and methylene groups are described so as to communicate the two benzene rings constituting the naphthalene ring , a hydroxyl group, such as substituents R ₃ and methylene group that may be attached anywhere substitutable position of the naphthalene ring.

In the unit represented by the general 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, and a sulfonic acid. Represents a sodium group, a nitro group, or an amino group. R ₃ is preferably hydrogen, methyl group, ethyl group, propyl group, butyl group, t-butyl group, or propyl group, more preferably hydrogen or methyl group, and further preferably hydrogen. This is preferable from the viewpoint of the manufacturing handleability of the phenolic resin composition for a photoresist and the balance of sensitivity, residual film ratio, resolution, heat resistance, and etching resistance of the photoresist composition.

In the unit represented by the general formula (10), c represents the number of the substituent 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, respectively. From the viewpoint of the balance of sensitivity, residual film ratio, resolution, heat resistance, and etching resistance of the phenolic resin composition for photoresist, c is preferably 1.

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

In the unit represented by the general formula (10), R ₄ represents a substituent bonded to a benzene ring having a phenolic hydroxyl group. R ₄ represents a hydrogen or methyl group. If the unit shown in the structure of the novolak type phenolic resin (B) in the general formula (10) include a plurality, the plurality of R ₄ contained in the structure of the novolak type phenolic resin (B), have the same or different You may. Handling and production on when the photoresist phenolic resin composition, the sensitivity when the photoresist composition, residual film ratio, resolution, from the viewpoint of heat resistance, etch resistance, R ₄ is a methyl group Is preferable. Further, when R ₄ is a methyl group, the bond position is preferably a para position with respect to the phenolic hydroxyl group bonded to the benzene ring.

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

(In the general formula (11), R ₃ , R ₄ and c are the same as the definitions in the general formula (10). Gamma represents an integer of 0 or more.)

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

(In the general formula (11'), γ is the same as the definition in the general formula (11).)

The polystyrene-equivalent weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) of a novolak-type phenolic resin (B) containing a naphthalene skeleton in its structure is used in the production of a phenolic resin composition for a photoresist. From the viewpoint of handleability and performance of the photoresist composition, 300 to 10000 is preferable, 500 to 8000 is more preferable, 500 to 5000 is further preferable, 500 to 3000 is further preferable, and 500 to 1000 is particularly preferable. If the weight average molecular weight is less than 300, the sensitivity may be too high or the heat resistance may be inferior, and if it is more than 10,000, the sensitivity may be low.

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

[Method for producing novolak-type phenolic resin (B) containing naphthalene skeleton in its structure]
The novolak-type phenolic resin (B) containing a naphthalene skeleton in its structure includes a naphthol compound (c1) represented by the following general formula (12), a phenol compound (c2) represented by the following general formula (13), and formaldehyde (c3). Can be preferably obtained by subjecting to a condensation reaction in the presence of an acid catalyst.

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

(In the general formula (12), _{R 3} and c are the same as defined in the general formula (10).)

Examples of the naphthol compound represented by the general formula (12) are not particularly limited, but α-naphthol, 1-hydroxy-2-naphtholic acid, 4-methoxy-1-naphthol, 2-acetyl-1-naphthol, Preferred examples thereof include sodium 1-naphthol-4-sulfonate, 4-nitro-1-naphthol, 4-chloro-1-naphthol, 6-amino-1-naphthol, β-naphthol and the like. Of these, α-naphthol is preferable from the viewpoint of easy availability and performance of the photoresist composition.

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

(In the general formula (13), R ₄ is the same as the definition in the general formula (10).)

Examples of the phenol compound represented by the general formula (13) are not particularly limited, but phenol, о-cresol, m-cresol, p-cresol and the like can be preferably mentioned. Of these, phenol and paracresol are preferable from the viewpoint of easy availability and performance of the photoresist composition.

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

<Mole ratio of phenolic component consisting of naphthol compound (c1) and phenol compound (c2) to formaldehyde (c3) [c3 / (c1 + c2)]>
In the production of a novolak-type phenolic resin (B) containing a naphthalene skeleton in its structure, when the naphthol compound (c1), the phenol compound (c2) and formaldehyde (c3) are reacted, the naphthol compound (c1) and the phenol compound are reacted. Formaldehyde (c3) is preferably 0.1 to 1.0 mol, more preferably 0.3 to 0.6 mol, with respect to 1 mol of the phenolic component (c1 + c2) composed of (c2).
By setting the molar ratio of the phenolic component (c1 + c2) to formaldehyde (c3) in the above range, the weight average molecular weight (Mw) of the novolak-type phenolic resin (B) containing the naphthol skeleton used in the present invention in its structure. Can be set to a preferable range.

<Mole ratio of naphthol compound (c1) and phenol compound (c2) (c2 / c1)>
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 phenol compound (c2) was such that the phenol compound (c2) was compared with 1 mol of the naphthol compound (c1). ) Is preferably 0.1 to 1.0 mol, more preferably 0.3 to 0.6 mol.
The molar ratio of the naphthol compound (c1) and the phenol compound (c2) within the above range is from the viewpoint of the balance of sensitivity, residual film ratio, resolution, heat resistance, and etching resistance of the photoresist composition. preferable.

In the production of novolak type phenol resin (B) containing a naphthalene skeleton in its structure, various conditions such as <acid catalyst>, <reaction solvent>, <reaction temperature>, <reaction time, reaction pressure> and <post-treatment> Can be produced under conventionally known conditions. For example, it can be produced under the same conditions as those in the above-mentioned method for producing the novolak type phenol resin (A).

In the production of the novolak type phenol resin (B) containing a naphthalene skeleton in its structure, as another production method, for example, a phenol compound (c2) and formaldehyde (c3) are reacted under a basic catalyst to form a phenol component dimethylol. A novolak-type phenolic resin is obtained by a two-step reaction (stepwise method) in which a body is obtained, and then the obtained dimethylol compound as a phenol component and a naphthol compound (c1), which is a compound containing a naphthalene skeleton, are reacted under an acid catalyst. (B) can be obtained.
Specifically, paracresol and formaldehyde (c3) as a phenol compound (c2) are reacted in water at a reaction temperature of 40 to 50 ° C. for 3 to 6 hours under a basic catalyst such as sodium hydroxide to paracresol. Dimethylol having a methylol group at two ortho positions with respect to the phenolic hydroxyl group of the above was obtained, and then the obtained dimethylol of paracresol and α-naphthol as the naphthol compound (c1) were used without solvent or in water, methanol, ethanol, etc. In a solvent such as propanol, butanol, toluene, methyl isobutyl ketone, under an acid catalyst such as oxalic acid, benzenesulfonic acid, paratoluenesulfonic acid, methanesulfonic acid, hydrochloric acid, sulfuric acid or phosphoric acid, at a reaction temperature of 40 to 85 ° C. Allow to react for 15 hours. The novolak type phenolic resin (B) can be obtained by removing the unreacted raw material by washing with water as a post-treatment and then distilling under reduced pressure at 200 ° C. or lower.

[Phenolic resin composition for photoresist]
The phenolic resin composition for a photoresist of the present invention contains a novolak-type phenol resin (A) represented by the general formula (1) and a novolac-type phenol resin (A) containing at least one of an arylene skeleton and a naphthalene skeleton in its structure. B) is obtained by polymer blending (mixing).

The phenolic resin composition for photoresist of the present invention is obtained by a polymer blend of a novolak type phenol resin (A) and a novolak type phenol resin (B), and the ratio thereof is the novolak type phenol resin (A) and the novolak type. When the total mass of the phenol resin (B) is 100, the mass ratio of the novolak type phenol resin (A) and the novolak type phenol resin (B) is 5 to 95: 95 to 5, preferably 10. It is ~ 90: 90-10, more preferably 30-90: 70-10, still more preferably 50-90: 50-10, and particularly preferably 60-80: 40-20.
When the novolak type phenol resin (B) has the structure of the above formula (5) or (5'), the mass ratio of the novolak type phenol resin (A) and the novolak type phenol resin (B) is 60 to 80. : 40 to 20 is particularly preferable, and 60 to 70:40 to 30 is most preferable.
When the novolak-type phenol resin (B) has the structure of the formula (6) or (6'), the mass ratio of the novolak-type phenol resin (A) to the novolak-type phenol resin (B) is 60. It is particularly preferably from ~ 90:40 to 10, and most preferably from 60 to 80:40 to 20.
When the ratio of the novolak type phenol resin (B) is less than 5% by mass, the effect of etching resistance and adhesion when the photoresist composition is obtained becomes small, while when it exceeds 95% by mass, the photoresist The sensitivity of the composition may be too high or the heat resistance may be inferior, which is not preferable in terms of handling.

The polystyrene-equivalent weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) of the phenolic resin composition for a photoresist of the present invention is preferably 300 to 10,000 from the viewpoint of the performance of the photoresist composition. 2000 to 8000 is more preferable, 3000 to 7000 is further preferable, and 4500 to 6500 is particularly preferable. If the weight average molecular weight is less than 300, the sensitivity may be too high or the heat resistance may be inferior, and if it is more than 10,000, the sensitivity may be low.

The alkali dissolution rate (DR) of the phenolic resin composition for photoresist of the present invention is preferably 50 to 2000 angstrom / sec from the viewpoint of sensitivity, residual film ratio, and resolution when the photoresist composition is used. More preferably, it is 100 to 1500 angstrom / sec. If the alkali dissolution rate is too fast or too slow, the photoresist composition tends to be difficult to handle. The alkali dissolution rate in the present specification is the alkali dissolution rate measured by the method described in Examples described later.

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

[Manufacturing method of phenolic resin composition for photoresist]
In the method for producing the phenolic resin composition for photoresist of the present invention, the polymer blending (mixing) method is any method as long as the novolak-type phenol resin (A) and the novolak-type phenol resin (B) can be uniformly mixed. There is no particular limitation. For example, it can be obtained by melting and mixing a novolak type phenol resin (A) and a novolak type phenol resin (B).
Specifically, as one manufacturing method, a novolak-type phenol resin (A) is synthesized in advance in a synthetic kettle, a novolak-type phenol resin (B) is added thereto, melt-mixed, and then post-treatment is performed. , The phenolic resin composition for photoresist of the present invention can be produced. In some cases, the novolak-type phenol resin (B) is synthesized in advance in a synthetic kettle, the novolak-type phenol resin (A) is added thereto, melt-mixed, and then treated to treat the phenolic resin for photoresist of the present invention. The composition can also be obtained.
Further, when producing a photoresist composition, each of the above novolac type phenolic resins and other additives described later can be dissolved in an appropriate solvent to obtain a photoresist composition.

[Photoresist composition]
The photoresist composition of the present invention further contains the phenolic resin composition for photoresist of the present invention and the photosensitive agent (E).

As the photosensitizer (E), a known photoresist of a photoresist containing a novolak type phenol resin can be used. As the photosensitizer (E), a quinone diazide compound having a quinone diazide group is preferable, and a 1,2-quinone diazide compound or a derivative thereof is particularly preferable.

By using the quinonediazide compound, the alkali dissolution rate of the exposed part increases due to the dissolution promoting effect, and conversely, the alkali dissolution rate of the unexposed part decreases due to the dissolution suppressing effect. Due to the difference, a sharp resist pattern with high contrast can be obtained.

As the quinone diazide compound, a known compound conventionally used in a quinone diazido-novolak resist can be used. Examples of the compound containing such a quinone diazide group include a compound obtained by reacting naphthoquinone diazido sulfonic acid chloride, benzoquinone diazido sulfonic acid chloride, or the like with a compound having a functional group capable of condensing with these acid chlorides. preferable. Here, examples of the functional group capable of condensation reaction with acid chloride include a hydroxyl group and an amino group, and a hydroxyl group is particularly preferable. Examples of the compound having a hydroxyl group capable of condensing with acid chloride include hydroquinone, resorcin, 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, 2,2', 3,4,6'-pentahydroxybenzophenone Hydroxybenzophenones such as bis (2,4-dihydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) methane, hydroxyphenyl alkanes such as bis (2,4-dihydroxyphenyl) propane, 4, 4', 3 ", 4" -Tetrahydroxy-3,5,3', 5'-Tetramethyltriphenylmethane, 4,4', 2 ", 3", 4 "-Pentahydroxy-3,5,3 Hydroxytriphenylmethanes such as', 5'-tetramethyltriphenylmethane can be mentioned. These compounds may be used alone or in combination of two or more.

Specific examples of acid chlorides such as naphthoquinone diazide sulfonic acid chloride and benzoquinone diazido sulfonic acid chloride include 1,2-naphthoquinone diazide-5-sulfonyl chloride and 1,2-naphthoquinone diazido-4-sulfonyl chloride. It is mentioned as preferable.

The blending amount of the photosensitizer (E) is preferably 5 to 50 parts by mass, more preferably 10 to 40 parts by mass with respect to 100 parts by mass of the phenolic resin composition for photoresist. If the blending amount of the photosensitive agent (B) is less than 5 parts by mass, sufficient sensitivity may not be obtained as a photosensitive tree composition, and if it is more than 50 parts by mass, there is a problem of precipitation of components. It may happen.

In addition to the above-mentioned photosensitive agent (E), the photoresist composition of the present invention includes stabilizers such as antioxidants, plasticizers, surfactants, and adhesion improvers, which are commonly used components of the photoresist composition. A dissolution accelerator, a dissolution inhibitor and the like can be appropriately added.

The phenolic resin composition for photoresist of the present invention and the photoresist composition of the present invention using the same can be suitably used for lithography in manufacturing a highly integrated semiconductor and a thin film transistor (TFT) material for liquid crystal.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[1] Novolac type phenol resin (A), novolak type phenol resin (B)
The analysis method and evaluation method of the novolak type phenol 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. Column: Shodex LF-804 1 piece Measurement condition: Column pressure 2.7 MPa
Eluent: tetrahydrofuran (THF)
Flow rate: 1 mL / min
Temperature: 40 ° C
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) to prepare a resin solution. These were filtered through a 0.2 micron membrane filter. This was 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. Next, a developing solution (1.60% tetramethylammonium hydrooxide aqueous solution) was used, and the time until the film completely disappeared was measured. The value obtained by dividing the initial film thickness by the time until dissolution was defined as the dissolution rate.

(3) Softening point (SP)
It was carried out by the ring-ball method softening point measurement based on JIS K6910.

(4) Hydroxyl Equivalent The hydroxyl group equivalent was measured according to JIS K0070.

[Novolak type phenol resin (A)]
[Synthesis Example A1] Novolac type phenolic resin (A1)
75.8 g (0.70 mol) of m-cresol, 113.8 g (1.05 mol) of p-cresol, 42% formalin 77. in a glass flask with a capacity of 1000 mL equipped with a thermometer, a charging / distilling outlet and a stirrer. 71 g (1.09 mol) and 0.7 g of formalin were added, and the mixture was reacted at 100 ° C. for 5 hours and then heated to 180 ° C. for dehydration. Then, unreacted raw material and the like were removed by vacuum distillation at 30 torr for 2 hours to obtain 142 g of meta-paracresol novolac type phenol resin (A1).
The obtained meta-paracresol novolac type phenol resin (A1) had a weight average molecular weight of 5900, an alkali dissolution rate of 330 angstrom / sec, a softening point of 142 ° C., and a hydroxyl group equivalent of 128 g / eq.

[Synthesis Example A2] Novolac type phenolic resin (A2)
A meta-paracresol novolac type phenol resin (A2) was obtained by the same procedure as in Synthesis Example A1 except that 42% formalin was changed to 75.25 g (1.05 mol). The weight average molecular weight of (A2) was 5000, the alkali dissolution rate was 480 angstroms / sec, the softening point was 140 ° C., and the hydroxyl equivalent was 127 g / eq.

[Synthesis Example A3] Novolac type phenolic resin (A3)
A meta-paracresol novolac type phenol resin (A3) was obtained by the same procedure as in Synthesis Example A1 except that 42% formalin was changed to 83.97 g (1.18 mol). The weight average molecular weight of (A3) was 12000, the alkali dissolution rate was 100 angstroms / sec, the softening point was 158 ° C., and the hydroxyl equivalent was 125 g / eq.

[Synthesis Example A4] Novolac type phenolic resin (A4)
The dimer component (n = 0) of the meta-paracresol novolac type phenol resin A1 obtained in Synthesis Example A1 was reduced by steam distillation.
The obtained meta-paracresol novolac type phenol resin (A4) had a weight average molecular weight of 6300, an alkali dissolution rate of 310 angstrom / sec, a softening point of 155 ° C., and a hydroxyl group equivalent of 130 g / eq.

[Synthesis Example A5] Novolac type phenolic resin (A5)
80.0 g (0.74 mol) of m-cresol, 80.0 g (0.74 mol) of p-cresol, 42% formalin 70. in a glass flask with a capacity of 1000 mL equipped with a thermometer, a charging / distilling outlet and a stirrer. 9 g (0.99 mol) and 0.6 g of oxalic acid were added, and the mixture was reacted at 100 ° C. for 5 hours and then heated to 180 ° C. for dehydration. Then, unreacted raw material and the like were removed by vacuum distillation at 30 torr for 2 hours to obtain 144 g of novolak type phenol resin (A5).
The obtained meta-paracresol novolak type phenol resin (A5) had a weight average molecular weight of 12000, an alkali dissolution rate of 170 angstrom / sec, a softening point of 162 ° C., and a hydroxyl group equivalent of 123 g / eq.

[Synthesis Example A6] Novolac type phenolic resin (A6)
94.7 g (0.88 mol) of m-cresol, 142.1 g (1.32 mol) of p-cresol, о-cresol 26. in a glass flask with a capacity of 1000 mL equipped with a thermometer, a charging / distilling outlet and a stirrer. 32 g (0.24 mol), 42% formalin 116.6 g (1.63 mol), and 0.92 g of oxalic acid were added, and the mixture was reacted at 100 ° C. for 10 hours and then heated to 180 ° C. for dehydration. Then, unreacted raw material and the like were removed by vacuum distillation at 30 torr for 2 hours to obtain 172 g of cresol novolac type phenol resin (A6).
The obtained novolak-type cresol resin (A6) had a weight average molecular weight of 6200, an alkali dissolution rate of 313 angstroms / sec, and a softening point of 141 ° C.

[Synthesis Example A7] Novolac 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 of resorcin (17.9 mol) in a glass flask with a capacity of 1000 mL equipped with a thermometer, a charging / distilling outlet and a stirrer. 0.16 mol), 69.74 g (0.98 mol) of 42% formalin, and 1.8 g of oxalic acid were added, and the mixture was reacted at 100 ° C. for 5 hours and then heated to 180 ° C. for dehydration. Then, unreacted raw material and the like were removed by vacuum distillation at 30 torr for 2 hours to obtain 141 g of novolak type phenol resin (A7).
The obtained novolak-type cresol resin (A7) had a weight average molecular weight of 9000, an alkali dissolution rate of 668 angstroms / sec, and a softening point of 153 ° C.

[Novolak type phenol resin (B)]
Novolac type phenolic resin (B1)
Novolac-type phenolic resin (weight average molecular weight: 1200, alkali dissolution rate: 4861 angstrom / sec, softening point: 65 ° C., hydroxyl group equivalent: 175 g) represented by the following general formula (14) and containing a benzene ring as an arylene skeleton in its structure. / Eq).

(In general formula (14), α represents an integer of 0 or more.)

Novolac type phenolic resin (B2)
Novolac-type phenolic resin (weight average molecular weight: 4500, alkali dissolution rate: 63 angstrom / sec, softening point: 86 ° C., hydroxyl group equivalent: 178 g) represented by the general formula (14) and containing a benzene ring as an arylene skeleton in its structure. / Eq).

Novolac type phenolic resin (B3)
Novolac-type phenolic resin (weight average molecular weight: 1070, alkali dissolution rate: 828 angstrom / sec, softening point: 66 ° C., hydroxyl group equivalent: 203 g) represented by the following general formula (15) and containing a biphenyl ring as an arylene skeleton in its structure. / Eq).

(In general formula (15), β represents an integer of 0 or more.)

Novolac type phenolic resin (B4)
Novolac-type phenolic resin (weight average molecular weight: 1400, alkali dissolution rate: 95 angstrom / sec, softening point: 73 ° C., hydroxyl group equivalent: 206 g) represented by the general formula (15) and containing a biphenyl ring as an arylene skeleton in its structure. / Eq).

Novolac type phenolic resin (B5)
Novolac-type phenolic resin (weight average molecular weight: 730, alkali dissolution rate: 5768 angstrom / sec, softening point: 114, hydroxyl group equivalent: 143 g / second) containing naphthalene skeleton as an arylene skeleton in the structure represented by the following general formula (16). eq).

(In general formula (16), γ represents an integer of 0 or more.)

Table 1 shows a summary of the novolak type phenol resin (A) and the novolak type phenol resin (B).

[2] Polyresist Phenolic Resin Composition, photoresist Composition Next, examples of the photoresist phenolic resin composition of the present invention and a photoresist composition using the same will be shown.
The analysis method and evaluation method of the phenolic resin composition for photoresist and the photoresist composition are as follows.

<Phenolic resin composition for photoresist>
The weight average molecular weight (Mw), (2) alkali dissolution rate (DR), and (3) softening point (SP) were measured by the same method as the analysis method and evaluation method of the novolak type phenol resin.

<Photoresist composition>
(1) Sensitivity, residual film ratio, resolution The photoresist composition was applied onto a 4-inch silicon wafer with a spin coater and dried on a hot plate at 110 ° C. for 60 seconds to form a coating film having a thickness of 15,000 Å. Then, using a reduced projection exposure apparatus, the exposure time was changed stepwise to confirm the optimum exposure amount, and then the exposure was performed so as to obtain the optimum exposure amount. Then, a developing solution (2.38% tetramethylammonium hydrooxide aqueous solution) was used, developed for 60 seconds, rinsed and dried.

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

It was determined residual film ratio from the remaining film thickness of the residual film ratio unexposed portion. The residual film ratio is the ratio of the film thickness of the photosensitive resin after development to the film thickness of the photosensitive resin before development, and is a value represented by the following formula.
Residual film ratio (%) = (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.
X: 2.0 μ line & space cannot be resolved.

(2) Dry etching resistance The resist film obtained with a positive pattern is dry-etched using a CF ₄ as an etching gas under etching conditions of 0.7 sccm and 80 W, and then etched. The etching rate of the resist pattern was determined by measuring the film thickness before and after. The results were compared with the etching rate when only the novolak type phenol resin (A) was used as the photoresist phenol resin composition.
The ratio of the etching rate of the novolak-type phenolic resin composition for photoresist to the etching rate of 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 novolak type phenol resin (A)]) was evaluated according to the following criteria.
⊚: When less than 0.75 ○: When 0.75 or more and 0.90 or less ×: When exceeding 0.90

[Example 1]
The novolak-type phenolic resin (A2) obtained in Synthesis Example A2 and the novolak-type phenolic resin (B1) obtained in Synthesis Example B1 were melt-mixed to prepare a phenolic resin composition for a photoresist. Specifically, 70 g of novolak-type phenol resin (A2) and 30 g of novolak-type phenol resin (B1) are mixed in a glass flask having a capacity of 500 mL equipped with a thermometer, a charging / distillation outlet, and a stirrer as shown in Table 1 below. To prepare a phenolic resin composition for a photoresist was prepared by melting and mixing in a temperature condition of 185 ° C.
The weight average molecular weight of the obtained phenolic resin composition for photoresist was 3300, the alkali dissolution rate was 1210 angstroms / sec, and the softening point was 139 ° C.
Table 2 shows the results of evaluating the properties of this phenolic resin composition for photoresist.

Next, the photoresist composition was prepared using the obtained phenolic resin composition for photoresist. Specifically, 20 g of a phenolic resin composition for a photoresist and 5 g of 1,2-naphthoquinonediazide-5-sulfonyl chloride are dissolved in 75 g of PGMEA (propylene glycol monomethyl ether acetate), and this is dissolved in a 0.2 micron membrane. Filtering with a filter gave a photoresist composition.
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 the synthetic example are melt-mixed by the same method as in Example 1 according to the formulation shown in Table 2 below. To obtain a phenolic resin composition for photoresist.
Table 2 shows the results of evaluating the properties of the obtained phenolic resin composition for photoresist.
Next, using the obtained phenolic resin composition for photoresist, a photoresist composition was obtained by the same method as in Example 1.
Table 2 shows the results of evaluating the properties of the obtained photoresist composition.

As is clear from the results shown in Table 2, it can be seen that the photoresist compositions obtained in each example have high developability such as high sensitivity, high residual film ratio, and high resolution, and are further excellent in etching resistance. ..
For example, from the comparison between Example 2 and Comparative Example 3, the resist composition using the photoresist phenol resin composition of Example 2 is compared with the case where the novolak type phenol resin A3 of Comparative Example 3 is used alone. It can be seen that the dry etching resistance is improved.
Further, from the comparison between Example 2 and Comparative Example 8, it can be seen that the resist composition of Example 2 has an improved residual film ratio as compared with that of Comparative Example 8.
Further, from the comparison between Example 2 and Comparative Example 3 and Comparative Example 8, the resolution of the resist composition of Example 2 was carried out even though the resolution of Comparative Example 3 was ◯ and the resolution of Comparative Example 8 was ×. It can be seen that the resolution of Example 2 is improved to ◎.

Claims (4)

The novolac-type phenolic resin (A) represented by the following general formula (1) and the novolac-type phenolic resin (B) containing at least one of an arylene skeleton and a naphthalene skeleton in the structure are referred to as (A) and (B). A phenolic resin composition for a photoresist, which comprises an amount having a mass ratio of 5 to 95: 95 to 5.

(In the general formula (1), R ₁ represents hydrogen or a linear or branched alkyl group having 1 or more and 8 or less carbon atoms, which may be the same or different from each other, but at least R ₁ . One is a linear or branched alkyl group having 1 or more and 8 or less carbon atoms. P is 1 or more and 3 or less, and they may be the same or different. Q is 1 or more and 3 or less. Yes, they may be the same or different, respectively. However, p + q ≦ 4. n represents an integer of 0 or more.) The phenolic resin composition for a photoresist according to claim 1, wherein the novolak-type phenolic resin (B) contains a unit represented by the following general formula (4) in its structure.

(In the 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. When b is 1 or more and 3 or less and b is 2 or more, R ₂ may be the same or different, respectively. However, a + b ≦ 4. When a plurality of units represented by the general formula (4) are contained in the structure of the novolak type phenol resin (B), the plurality of a, b and R ₂ contained in the structure of the novolak type phenol resin (B) are present. , Each may be the same or different. ) The phenolic resin composition for a photoresist according to claim 1, wherein the novolak-type phenolic resin (B) contains a unit represented by the following general formula (10) in its structure.

(In the general 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, and the like. Represents an alkoxy group, an acetyl group, a sodium sulfonate group, a nitro group, or an amino group. R ₄ represents a hydrogen or methyl group. C is 1 or more and 3 or less, and when c is 2 or more, R ₃ may be the same or different from each other. When a plurality of units represented by the general formula (10) are included in the structure of the novolak type phenol resin (B), the structure of the novolak type phenol resin (B) includes a plurality of units. The plurality of c, R ₄ and R ₃ included may be the same or different, respectively.) A photoresist composition comprising the phenolic resin composition for a photoresist according to any one of claims 1 to 3 and a photosensitive agent.