KR20200051748A - Phenolic resin composition for photoresist and photoresist composition - Google Patents

Abstract

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

Description

Phenolic resin composition for photoresist and photoresist composition

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

In recent years, the line width of circuit patterns of integrated circuit semiconductors has been walking toward miniaturization along with high density of integration. In addition, in the liquid crystal display device and the like, the line width tends to be thinner and finer. As the size and low cost of the display panel are progressing, there is a need for a technology capable of stably forming a wiring 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 has been widely used, but the technique is also applied to the manufacturing process of a liquid crystal display device. There is this.

Accordingly, the required performance for the photoresist resin material is also advanced and diversified, and it is necessary to excel in high developability such as high sensitivity, high residual film rate, high resolution, and further excellent etching resistance such as wet etching resistance and dry etching resistance.

A cresol novolak-type phenol resin is mentioned as a phenol resin most widely used for photoresist use (for example, patent document 1).

Japanese Patent Application Publication No. Hei 2-55359

However, the cresol novolak-type phenol resin as described in Patent Literature 1 is not capable of responding to the market demand performance of these days, while the above-mentioned advancement and diversification is in progress, and also has insufficient etching resistance.

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

As a result of earnest review to solve the above problems, the present inventors have novolak-type phenolic resins (B) containing a specific structure of the novolac-type phenolic resin (A) represented by a specific general formula and an arylene skeleton or a naphthalene skeleton in a resin skeleton. ), The photoresist composition using the phenol resin composition for photoresists obtained by polymer blending was found to be excellent in etching resistance while having excellent developability such as high sensitivity, high residual film rate, and high resolution, and to reach the present invention.

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

1. The novolac-type phenolic resin (B) containing at least one of the novolac-type phenolic resin (A) represented by the following general formula (1) and an arylene skeleton and a naphthalene skeleton in the structures (A) and (B) The present invention relates to a phenolic resin composition for photoresists containing an amount in a mass ratio of 5 to 95:95 to 5.

[Formula 1]

(In the general formula (1), R ₁ represents hydrogen or a straight or branched alkyl group having 1 to 8 carbon atoms, and may be the same or different. However, at least one of R ₁ has 1 to 8 carbon atoms. Is a straight-chain or branched alkyl group, p is 1 or more and 3 or less, and may be the same or different, q is 1 or more and 3 or less, and may be the same or different, but p + q≤4, where n is 0 The above integer is represented.)

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

[Formula 2]

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

[Formula 3]

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, respectively. However, a + b≤4. On the other hand, when a plurality of units represented by formula (4) are included in the structure of the novolac-type phenol resin (B), a plurality of a, b and R ₂ included in the structure of the novolac-type phenol resin (B) are each It may be the same or different.)

3. In the above 1, it relates to a phenolic resin composition for a photoresist comprising a unit represented by the following general formula (10) in the novolac-type phenolic resin (B) in the structure.

[Formula 4]

(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, an alkoxy group, an acetyl group, or 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, R ₃ may be the same or different, respectively. When a plurality of units represented by the general formula (10) are included in the structure of the resin (B), the plurality of c, R ₄ and R ₃ contained in the structure of the novolac-type phenol resin (B) may be the same or different, respectively. )

4. It relates to the photoresist composition containing the phenol resin composition for photoresists and photosensitive agent in any one of said 1.-3.

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

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

[Formula 5]

(In the general formula (1), R ₁ represents hydrogen or a straight or branched alkyl group having 1 to 8 carbon atoms, and may be the same or different. However, at least one of R ₁ has 1 to 8 carbon atoms. Is a straight-chain or branched alkyl group, p is 1 or more and 3 or less, and may be the same or different, q is 1 or more and 3 or less, and may be the same or different, but p + q≤4, where n is 0 The above integer is represented.)

The phenolic resin composition for photoresists of the present invention comprises the novolac-type phenolic resin (A) and the novolac-type phenolic resin (B) together, and thus, when used as a photoresist composition, develops high sensitivity, high residual film ratio, and high resolution. , It has excellent etching resistance such as wet etching resistance and dry etching resistance.

(Novolak type phenolic resin (A))

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

In the novolac-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 represents hydrogen or a linear or branched alkyl group having 1 to 8 carbon atoms, and the plurality of R ₁ contained in the structure of the novolac-type phenol resin (A) may be the same or different, respectively. However, at least one of R ₁ is a straight or branched alkyl group having 1 to 8 carbon atoms. That is, the novolac-type phenol resin (A) necessarily has an alkyl-substituted phenol skeleton in which an alkyl group is bonded as a substituent R ₁ to a benzene ring having a phenolic hydroxyl group. R ₁ is preferably hydrogen, methyl group, ethyl group, propyl group, butyl group, t-butyl group, propyl group, vinyl group, octyl group. From the viewpoints of sensitivity, residual film ratio, resolution, and heat resistance when using a phenol resin composition for photoresist, R ₁ is more preferably a methyl group.

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

In the novolak-type phenol 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, "each may be the same or different" in p indicates that a plurality of ps contained in the structure of the novolac-type phenol resin (A) may be the same or different, respectively. However, the sum p + q with the number q of the above-mentioned substituent R ₁ is 4 or less. It is preferable that p is all 1 from a viewpoint of balance of sensitivity, residual film rate, resolution, and heat resistance when it is set as the phenol resin composition for photoresists. When the number of phenolic hydroxyl groups is large, the dissolution rate to alkali becomes too fast, and the handleability may be poor when used as a photoresist composition.

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 phenol resin (A) represented by the general formula (1) is an aggregate of polymers having various molecular weights, the value of n can be represented as the 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 is 1000 to 50000, as measured by GPC (gel permeation chromatography) of the novolac-type phenol resin (A), It is more preferable that it is 30000, it is more preferable that it is 1500-25000, it is particularly preferable that it is 3000-15000, and it is most preferable that it is 5000-12000.

The novolak-type phenol 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-described range as a phenol resin composition for photoresists. It is preferable from the viewpoints of handling properties in manufacturing and sensitivity, residual film ratio, resolution, and heat resistance when used as a photoresist composition. When the weight average molecular weight is less than 1000, the sensitivity may be too high or the heat resistance may be poor, and when it is greater than 50000, the sensitivity may be low.

The hydroxyl group equivalent of the novolak-type phenol 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 balance of sensitivity, residual film ratio, 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 embodiments in the novolac-type phenol resin (A) represented by the general formula (1) is that all p and q in the general formula (1) are 1 (p = 1, q = 1), and all substituents It is a cresol novolak resin represented by the following general formula (2) whose R is a methyl group.

[Formula 6]

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

The use of the cresol novolac resin represented by the general formula (2) as the novolac-type phenol resin (A) is preferable because a photoresist composition having a balance of sensitivity, residual film ratio, resolution and heat resistance can be obtained.

In the novolac-type phenol resin (A), which is one of the preferred embodiments represented by the general formula (2), the methyl group may be in any of the substituted positions of ortho, meta, or parawi with respect to the phenolic hydroxyl group. From the viewpoint of providing a balance of sensitivity, residual film ratio, resolution, and heat resistance when used as a photoresist composition, a structure having both a phenol skeleton substituted with a methyl group on meta and a phenol skeleton bound with a methyl group on para is preferable for the phenolic hydroxyl group. Do. It is more preferable that the novolak-type phenol resin (A) has a structure composed of a phenol skeleton in which a methyl group is substituted on the meta position with respect to a phenolic hydroxyl group, and a phenol skeleton in which a methyl group is bonded to the para position. The molar ratio of meta-wi: parawi can be adjusted by adjusting the molar ratio of the phenol compound (a1) when the raw material to be described later is introduced. At this time, the phenol skeleton having a methyl group substituted on the meta position of the general formula (2) and the phenol skeleton having a methyl group bonded to the para position have a molar ratio of 20 to 80: 80 to 20 when the raw material of the meta stomach: parawi is added. It is preferably an amount, more preferably 30 to 70:70 to 30, more preferably 40 to 60:60 to 40, 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 phenol resin (A) affects the etching resistance and alkali solubility of the resist composition. A photoresist composition having high etching resistance can be obtained by increasing the number of phenol skeletons on which methyl groups are bonded to para. It is preferred that the proportion of Parawi exceeds 50%. When the ratio of meta stomach is large, there is a concern that the alkali dissolution rate is increased and the residual film ratio is lowered. If the ratio of meta stomach is up to 50%, there is no concern.

[Production Method of Novolac Type Phenolic Resin (A)]

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

<Phenol compound (a1)>

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

[Formula 7]

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

The phenol compound represented by the general formula (3) is not particularly limited, and the compound of p = 1 is phenol, m-cresol, p-cresol, o-cresol, 2,3-xyllenol, 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.

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

In addition, examples of the compound of P = 3 include hydroxyquinol, fluoroglycinol, and pyrogallol.

These phenolic compounds can be used alone or in combination of two or more. However, the alkyl-substituted phenol compound in which R ₁ is a straight or branched alkyl group having 1 to 8 carbon atoms is included as an essential component.

In particular, when using a photoresist composition, it is preferable to use m-cresol, p-cresol, or o-cresol cresols as a phenol compound (a1) from the viewpoint of providing a balance of sensitivity, residual film rate, resolution, and heat resistance. , m-cresol, p-cresol is more preferably used, and m-cresol and p-cresol are used 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, more preferably 30 to 70:70 to 30 The amount is preferably 40 to 60:60 to 40, more preferably 40 to 50:60 to 50.

<Formaldehyde (a2)>

Further, the formaldehyde (a2) is not particularly limited, and an aqueous formaldehyde solution may be used, or a polymer that decomposes in the presence of an acid such as paraformaldehyde or trioxane to formaldehyde may be used. It is preferably a formaldehyde aqueous solution that is easy to handle, and a commercially available 42% formaldehyde aqueous solution can be 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 novolac-type phenolic resin (A), the formaldehyde (a2) is preferably 0.2 to 1.0 mol with respect to 1 mol of the phenolic compound (a1), More preferably, it is 0.5 to 0.9 mol.

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

<Acid catalyst>

The reaction conditions of the condensation polymerization reaction in the production of the novolac-type phenol resin (A) of the present invention may be conventionally known reaction conditions applied when preparing a conventional phenol resin. That is, the acid catalyst to be used is not particularly limited as long as it is an acid capable of reacting a phenol component and a formaldehyde component. For example, organic sulfonic acids such as oxalic acid, benzenesulfonic acid, p-toluenesulfonic acid, and methanesulfonic acid , Inorganic acids such as hydrochloric acid and sulfuric acid, or a combination of two or more. Among them, sulfuric acid, oxalic acid or p-toluenesulfonic acid is particularly preferred.

The acid catalyst is used in an amount of about 0.01 to 1% by mass relative to the phenol component (a1). When the novolac-type phenol resin (A) is used in the composition for photoresists, the acid catalyst remaining in the resin may affect the properties of the photoresist, so the smaller one is preferable. The preferred amount varies depending on the type, and 0.3 to 1.0 mass% for oxalic acid, 0.05 to 0.1 mass% for sulfuric acid, and 0.1 to 0.5 mass% for p-toluenesulfonic acid is preferred.

<Reaction solvent>

As the reaction solvent, water contained in the formaldehyde of the raw material may play a role of the solvent. In addition to water, an organic solvent that does not affect the reaction may be used as needed. 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.

The amount of the reaction solvent 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 condensation polymerization 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 it is lower than 50 ° C, the reaction is difficult to proceed, and when it exceeds 200 ° C, the reaction control becomes difficult, and it is difficult to stably obtain the desired novolac-type phenol resin (A).

<Reaction time, reaction pressure>

The reaction time of the condensation polymerization reaction also depends on the reaction temperature, and is usually about 0.1 to 20 hours. In addition, the reaction pressure of the condensation polymerization reaction is usually carried out under normal pressure, but may be performed under pressure or under reduced pressure.

<Post-processing>

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

The base for neutralizing the acid catalyst is not particularly limited, and may be used as long as it neutralizes the acid catalyst and forms a salt soluble in water. And 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, and calcium carbonate. Examples of the organic base amine or organic amine include ammonia, trimethylamine, triethylamine, diethylamine, and tributylamine. Organic amines are preferably used. The amount of use also depends on the amount of the acid catalyst. It is preferred 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 the washing and the number of washing are not particularly limited. In order to remove the acid catalyst to an amount that does not affect actual use, including economic viewpoint, the washing frequency is preferably 1 to 5 times. In addition, although the temperature of water washing is not specifically limited, It is preferable to carry out at 40-95 degreeC from a viewpoint of efficiency and workability of catalyst species removal. In the case where the separation between the novolac-type phenol resin (A) and the wash water is poor during water washing, it is effective to increase the temperature of the water or the addition of a solvent in order to lower the viscosity of the mixed solution. The solvent species is not particularly limited, but can be used as long as it dissolves the novolac-type phenol resin (A) and lowers the viscosity.

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

[Novolak type phenolic resin (B)]

In the phenol resin composition for photoresists of the present invention, the novolac-type phenol resin (B) contains at least one of an arylene skeleton and a naphthalene skeleton in the structure. The phenolic resin composition for photoresists of the present invention contains a novolac-type phenolic resin (B), so that when used as a photoresist composition, developability such as high sensitivity, high residual film rate, high resolution, and etching resistance such as wet etching resistance or dry etching resistance Together, it becomes outstanding.

[Novolak-type phenol resin (B) containing arylene skeleton in structure]

The inclusion of the arylene skeleton in the structure in the novolak-type phenol resin (B) indicates that the unit (structural unit) of the following general formula (4) is included in at least one structure.

[Formula 8]

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

[Formula 9]

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, respectively. However, a + b≤4. On the other hand, when a plurality of units represented by formula (4) are included in the structure of the novolac-type phenol resin (B), a plurality of a, b and R ₂ included in the structure of the novolac-type phenol resin (B) are each It 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 a hydrogen, methyl group, ethyl group, propyl group, butyl group, t-butyl group, propyl group, more preferably hydrogen or methyl group, and more preferably hydrogen is a phenol resin composition for photoresist It is preferable from the viewpoints of the balance between the handling properties in manufacturing and the sensitivity, residual film ratio, resolution, heat resistance, and etching resistance when using a photoresist composition.

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. It is preferable that b is 1 from a viewpoint of the balance of sensitivity, residual film rate, resolution, heat resistance, and etching resistance when it is set as the phenol resin composition for photoresists.

In addition, when a plurality of units represented by the general formula (4) are included in the structure of the novolac-type phenol resin (B), the plurality of b and R ₂ contained in the structure of the novolak-type phenol resin (B) are the same or respectively. You may 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 a + b with the number b of the above-mentioned substituent R ₂ is 4 or less. It is preferable that a is 1 from a viewpoint of the balance of sensitivity, residual film rate, resolution, heat resistance, and etching resistance when using the phenol resin composition for photoresists.

In addition, when a plurality of units represented by the general formula (4) are included in the structure of the novolac-type phenol resin (B), a plurality of a contained in the structure of the novolak-type phenol resin (B) may be the same or different, respectively. That is, the novolac-type phenol resin (B) may include a monovalent phenol (a = 1) skeleton and a divalent phenol (a = 2) skeleton in the same structure.

The weight average molecular weight (Mw) in terms of polystyrene as measured by GPC (gel permeation chromatography) of the novolac-type phenol resin (B) containing an arylene skeleton in the structure is a manufacturing phenol resin composition. From the performance when used as a handling property or a photoresist composition, 300-10000 are preferred, 500-8000 are more preferred, 500-5000 are more preferred, 1000-1500 are particularly preferred, and 1200-1400 are extremely preferred. Do. When the weight average molecular weight is less than 300, the sensitivity may be too high or the heat resistance may be poor, and when it is larger than 10000, the sensitivity may be low.

The hydroxyl group equivalent of the novolak-type phenol 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 balance of sensitivity, residual film ratio, 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 preferable embodiments of the novolac-type phenol resin (B) containing the arylene skeleton in the structure is a novolac-type phenol resin represented by the following general formula (5) or (6).

[Formula 10]

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

[Formula 11]

(R ₂ , a and b in the general formula (6) are the same as defined in the general formula (4). Β represents an integer of 0 or more.)

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

[Formula 12]

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

[Formula 13]

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

The novolac-type phenolic resin (B) containing the arylene skeleton in the structure is a novolac-type phenolic resin represented by the general formula (5) or (5 '). It is preferable from a viewpoint of the balance of handling property, sensitivity when using a photoresist composition, residual film rate, resolution, heat resistance, and etching resistance.

[Method for producing a novolac-type phenol resin (B) containing an arylene skeleton in its structure]

The novolak-type phenol resin (B) containing an arylene skeleton in the structure includes 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). The compound (b2) containing can be suitably obtained by condensation reaction in the presence of a 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 the arylene skeleton in the structure is represented by the following general formula (7).

[Formula 14]

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

The example of the phenol compound represented by the general formula (7) is not particularly limited, and the compound of a = 1 is phenol, cresol, ethylphenol, propylphenol, butylphenol, hexylphenol, nonylphenol, xylenol, and butylmethylphenol. And monovalent phenol compounds. Among them, phenol is suitable.

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

These phenolic compounds can be used alone or in combination of two or more. When used as a photoresist composition, it is preferable to use phenol alone from the viewpoint of providing a balance of sensitivity, residual film ratio, resolution, and heat resistance. Especially preferred.

<A 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 novolac-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 mentioned, and is represented by the following general formula (8) or (9).

[Formula 15]

(X in general formula (8) or (9) represents an alkoxy group or 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 halogen.

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

Examples of the halogen include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a chlorine atom is preferred from the viewpoint of reactivity with a phenol compound and ease of availability.

As the compound containing the benzene ring represented by the general formula (8), 1,4-di (methoxymethyl) benzene, 1,3-di (methoxymethyl) benzene, 1,2-di (methoxymethyl) Benzene, 1,4-di (chloromethyl) benzene, 1,3-di (chloromethyl) benzene, 1,2-di (chloromethyl) benzene and the like are exemplified. Among them, 1,4-di (methoxymethyl) benzene or 1,4-di (chloromethyl) benzene is preferable from the viewpoint of sensitivity, residual film ratio, resolution, heat resistance, and etching resistance when used as a photoresist composition.

The compound containing the biphenyl ring represented by the general formula (9) is 4,4'-di (methoxymethyl) biphenyl, 2,4'-di (methoxymethyl) biphenyl, 2,2'- Di (methoxymethyl) biphenyl, 4,4'-di (chloromethyl) biphenyl, 2,4'-di (chloromethyl) biphenyl, 2,2'-di (chloromethyl) biphenyl, etc. Can be lifted. Among them, 4,4'-di (methoxymethyl) biphenyl or 4,4'-di (chloromethyl) biphenyl is considered from the viewpoint of sensitivity, residual film ratio, resolution, heat resistance and etching resistance when used as a photoresist composition. desirable.

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

In addition, as a component for crosslinking the phenol compound (b1) represented by the general formula (9), formaldehyde within the range not to interfere with the effects of the present invention together with the compound (b2) containing a benzene ring or a biphenyl ring. Can be used together.

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

When the phenol compound (b1) and the compound (b2) containing a benzene ring or a biphenyl ring are reacted in the production of a novolak-type phenol resin (B) containing an arylene skeleton in a structure, 1 mol of the phenol compound (b1) 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) and the compound (b2) containing a biphenyl ring or a benzene ring to the above range, the weight of the novolac type phenol resin (B) containing the arylene skeleton used in the present invention in the structure Average molecular weight (Mw) can be made into a preferable range.

In the production of a novolac-type phenolic resin (B) containing an arylene skeleton in a structure, it is suitable for production conditions such as <acid catalyst>, <reaction solvent>, <reaction temperature>, <reaction time, reaction pressure> and <post-treatment>. Regarding, it can be manufactured under conventionally known conditions. For example, it can be manufactured under conditions equivalent to those in the production method of the novolak-type phenol resin (A) described above.

[Novolak-type phenol resin (B) containing naphthalene skeleton in structure]

The inclusion of a naphthalene skeleton in a structure in the novolak-type phenol resin (B) indicates that the unit of the following general formula (10) is included in at least one structure.

[Formula 16]

(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, an alkoxy group, an acetyl group, or 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, R ₃ may be the same or different, respectively. When a plurality of units represented by the general formula (10) are included in the structure of the resin (B), the plurality of c, R ₄ and R ₃ contained in the structure of the novolac-type phenol resin (B) may be the same or different, respectively. )

On the other hand, in the general formula (10), a hydroxyl group, a substituent, and a hydroxyl group, a substituent R ₃ and a methylene group, which are bound to the naphthalene skeleton, are described so as to communicate two benzene rings constituting the naphthalene ring. It represents that R ₃ and a methylene group, etc., may be bonded to any of the naphthalene ring-substituted positions.

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, a sodium sulfonate group, a nitro group, or Represents an amino group. R ₃ is preferably hydrogen, a methyl group, an ethyl group, a propyl group, a butyl group, a t-butyl group, or a propyl group, more preferably hydrogen or a methyl group, and more preferably hydrogen is a phenol for photoresist It is preferable from the viewpoints of the balance of sensitivity, residual film ratio, resolution, heat resistance, and etching resistance when using a photoresist composition and manufacturing handling properties when using a resin 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. It is preferable that c is 1 from a viewpoint of the balance of sensitivity, residual film rate, resolution, heat resistance, and etching resistance when using the phenol resin composition for photoresists.

In addition, when a plurality of units represented by the general formula (10) is included in the structure of the novolac-type phenolic resin (B), the plurality of c and R ₃ contained in the structure of the novolac-type phenolic resin (B) are the same or respectively. You may be 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 hydrogen or a methyl group. When the unit represented by the following formula (10) in the structure of the novolak type phenolic resin (B) which comprises a plurality, the plurality of R ₄ may be the same or different, each contained in the structure of the novolak type phenolic resin (B). R ₄ is preferably a methyl group from the viewpoints of manufacturing handling properties when using a phenol resin composition for photoresist, sensitivity, residual film ratio, resolution, heat resistance, and etching resistance when using a photoresist composition. Moreover, when R <_4> is a methyl group, it is preferable that the bonding position is parawi with respect to the phenolic hydroxyl group couple | bonded with a benzene ring.

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

[Formula 17]

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

One of the more preferred embodiments of the novolac-type phenol resin (B) containing a naphthalene skeleton in the structure is all the substituents R ₃ in the general formula (11) are hydrogen, all the substituents R ₄ are methyl groups, and the phenolic bond to the benzene ring It is a novolac-type phenol resin represented by the following general formula (11 ') which consists of a repeating unit bonded to a parawi with respect to a hydroxyl group.

[Formula 18]

(Γ in the general formula (11 ') is the same as defined in the general formula (11).)

The weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) of a novolac-type phenol resin (B) containing a naphthalene skeleton in a structure is a manufacturing handling when a phenol resin composition for photoresist is used. From the performance when used as a sex or photoresist composition, 300-10000 are preferred, 500-8000 are more preferred, 500-5000 are more preferred, 500-3000 are even more preferred, and 500-1000 are particularly preferred. Do. When the weight average molecular weight is less than 300, the sensitivity may be too high or the heat resistance may be poor, and when it is larger than 10000, the sensitivity may be low.

The hydroxyl group equivalent of the novolac-type phenol resin (B) containing a naphthalene skeleton in the structure is 130 g / eq or more and 160 g / eq or less in terms of balance of sensitivity, residual film ratio, 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 novolac-type phenol resin (B) containing naphthalene skeleton in structure]

The novolac-type phenol resin (B) containing a naphthalene skeleton in a structure comprises 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). 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 a novolac-type phenol resin (B) containing a naphthalene skeleton in a structure is represented by the following general formula (12).

[Formula 19]

(R ₃ and c in the general formula (12) 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, α-naphthol, 1-hydroxy-2-naphthoic acid, 4-methoxy-1-naphthol, 2-acetyl-1-naphthol, 1-naphthol-4-sulfonic acid sodium, 4-nitro-1-naphthol, 4-chloro-1-naphthol, 6-amino-1-naphthol, β-naphthol, etc. are suitably mentioned. Among them, α-naphthol is preferred from the viewpoint of ease of availability and performance when used as a photoresist composition.

<Phenol compound (c2)>

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

[Formula 20]

(R ₄ in the general formula (13) is the same as defined in the general formula (10).)

Examples of the phenol compound represented by the general formula (13) are not particularly limited, and phenol, o-cresol, m-cresol, p-cresol and the like can be exemplified. Among them, phenol and paracresol are preferred from the viewpoint of ease of availability and performance when used as a photoresist composition.

<Formaldehyde (c3)>

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

<Molar ratio of phenolic components and formaldehyde (c3) consisting of a naphthol compound (c1) and a phenolic compound (c2) [c3 / (c1 + c2)]>

When the naphthol compound (c1), the phenolic compound (c2) and formaldehyde (c3) are reacted in the production of a novolac-type phenolic resin (B) containing a naphthalene skeleton in the structure, the naphthol compound (c1) and the phenolic compound (c2) The formaldehyde (c3) is preferably 0.1 to 1.0 mol, and more preferably 0.3 to 0.6 mol, per 1 mol of the phenol component (c1 + c2) consisting of.

By setting the molar ratio of the phenol components (c1 + c2) and formaldehyde (c3) to the above range, the weight average molecular weight (Mw) of the novolac-type phenol resin (B) containing the naphthol skeleton used in the present invention in the structure is preferred. You can do it with scope.

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

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

The molar ratio of the naphthol compound (c1) to the phenolic compound (c2) is within the above range, and it is preferable from the viewpoint of the balance of sensitivity, residual film ratio, resolution, heat resistance, and etching resistance when using a photoresist composition.

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

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

Specifically, while receiving paracresol and formaldehyde (c3) as a phenolic compound (c2), reacting with a basic catalyst such as sodium hydroxide at a reaction temperature of 40 to 50 ° C for 3 to 6 hours, to a phenolic hydroxyl group of paracresol. A dimethylol body having a methylol group on two ortho groups was obtained, and then the dimethylol body of paracresol obtained and α-naphthol as a naphthol compound (c1) were solvent-free or water, methanol, ethanol, propanol, butanol, toluene, methyl isobutyl In a solvent such as ketone, an acid catalyst such as oxalic acid, benzenesulfonic acid, paratoluenesulfonic acid, methanesulfonic acid, hydrochloric acid, sulfuric acid or phosphoric acid is reacted for 2 to 15 hours at a reaction temperature of 40 to 85 ° C. The unreacted raw material can be removed to obtain a novolac-type phenol resin (B) by washing with water as a post-treatment and then distilling under reduced pressure at 200 ° C. or lower under reduced pressure.

(Phenol composition for photoresist)

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

The phenolic resin composition for photoresists of the present invention is obtained by a polymer blend of a novolac-type phenolic resin (A) and a novolac-type phenolic resin (B), the ratio being novolac-type phenolic resin (A) and novolac-type When the total mass of the phenolic resin (B) is 100, the mass ratio of the novolac-type phenolic resin (A) and the novolac-type phenolic resin (B) is 5 to 95:95 to 5, preferably 10 to 90 : 90 ~ 10, More preferably, it is 30 ~ 90: 70 ~ 10, More preferably, it is 50 ~ 90: 50 ~ 10, Especially preferably, it is 60 ~ 80: 40 ~ 20.

When the novolac-type phenolic resin (B) has the structure of formula (5) or (5 '), the mass ratio of the novolac-type phenolic resin (A) and the novolac-type phenolic resin (B) is 60 to 80:40. It is particularly preferable that it is ∼20, and most preferably 60 to 70:40 to 30.

In addition, when the novolac-type phenolic resin (B) has the structure of formula (6) or (6 '), the mass ratio of the novolac-type phenolic resin (A) and the novolac-type phenolic resin (B) is 60 to 90 It is particularly preferable that it is: 40 to 10, and most preferably 60 to 80:40 to 20.

When the proportion occupied by the novolac-type phenolic resin (B) is less than 5% by mass, the effect of etching resistance and adhesion when used as a photoresist composition becomes small, while when it exceeds 95% by mass, when used as a photoresist composition The sensitivity of the film may be too high or the heat resistance may be poor, which is not preferable for 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, from 2000 to 2000, from the performance of the photoresist composition. 8000 is more preferable, 3000-7000 is more preferable, and 4500-6500 is particularly preferable. When the weight average molecular weight is less than 300, the sensitivity may be too high or the heat resistance may be poor, and when it 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 from the viewpoint of sensitivity, residual film ratio, and resolution when used as a photoresist composition. ~ 1500 Angstroms / sec. Even if the alkali dissolution rate is too fast or too slow, the handleability tends to deteriorate when the photoresist composition is used. In addition, the alkali dissolution rate in this specification is the alkali dissolution rate measured by the method described in the Example mentioned 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)

The method of polymer blending (mixing) in the method for producing the phenolic resin composition for photoresists of the present invention is particularly limited as long as it is a method capable of uniformly mixing the novolac-type phenolic resin (A) and the novolac-type phenolic resin (B). Does not work. For example, it can be obtained by melt-mixing a novolac-type phenolic resin (A) and a novolac-type phenolic resin (B).

Specifically, as a manufacturing method, a novolac-type phenol resin (A) is synthesized in advance in a synthetic kiln, and a novolac-type phenol resin (B) is added and melt-mixed, followed by post-treatment. It is possible to prepare a phenol resin composition for photoresist. In some cases, a novolac-type phenol resin (B) is synthesized in advance in a synthetic kiln, and a novolac-type phenol resin (A) is added, melt-mixed, and then processed to obtain a phenol resin composition for photoresists of the present invention. It might be.

In addition, when manufacturing a photoresist composition, each of the novolac-type phenol resins and other additives to be described later may be dissolved in a suitable solvent to obtain a photoresist composition.

(Photoresist composition)

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

As the photosensitive agent (E), a known photosensitive agent for a photoresist containing a novolac-type phenol resin 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 a quinonediazide compound, the exposed portion has a high alkali dissolution rate due to the dissolution promoting effect, and on the contrary, the portion not exposed has a low alkali dissolution rate due to the dissolution inhibiting effect, and the exposed portion and unexposed. A sharp resist pattern with high contrast can be obtained by the difference in the dissolution rate of the negative.

As the quinonediazide compound, a known compound that is conventionally used in quinonediazide-novolac-based resists can be used. The compound containing such a quinonediazide group is preferably a compound obtained by reacting a compound having a functional group capable of condensation reaction with these acid chlorides, such as naphthoquinone diazide sulfonic acid chloride or benzoquinone diazide sulfonic acid chloride. Here, examples of the functional group capable of condensation reaction with an acid chloride include a hydroxyl group and an amino group, and a hydroxyl group is particularly suitable. As a compound having a hydroxyl group capable of condensation reaction with an acid chloride, for example, 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, Hydroxybenzophenones such as 2,2 ', 3,4,6'-pentahydroxybenzophenone, bis (2,4-dihydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) Hydroxyphenyl alkanes such as methane and bis (2,4-dihydroxyphenyl) propane, 4,4 ', 3 ", 4" -tetrahydroxy-3,5,3', 5'-tetramethyl And hydroxytriphenylmethanes such as triphenylmethane, 4,4 ', 2 ", 3", 4 "-pentahydroxy-3,5,3', 5'-tetramethyltriphenylmethane. These compounds may be used alone or in combination of two or more.

Further, specific examples of the acid chloride, naphthoquinone diazide sulfonic acid chloride or benzoquinone diazide sulfonic acid chloride, for example, 1,2-naphthoquinone diazide-5-sulfonyl chloride, 1,2- Preferred examples include naphthoquinone diazide-4-sulfonyl chloride and the like.

The blending amount of the photosensitive agent (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 phenol resin composition for photoresist. When the compounding quantity of the photosensitive agent (B) is less than 5 parts by mass, sufficient sensitivity may not be obtained as a photosensitive water composition, and when more than 50 parts by mass, the problem of precipitation of components may occur.

In the photoresist composition of the present invention, in addition to the photosensitive agent (E), stabilizers such as antioxidants, plasticizers, surfactants, adhesion promoters, dissolution promoters, and dissolution inhibitors, etc., which are common components of the photoresist composition, can be suitably 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 or liquid crystal thin film transistor (TFT) materials for manufacturing highly integrated semiconductors.

Example

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

[1] novolac-type phenolic resins (A), novolac-type phenolic resins (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 to obtain a weight average molecular weight in terms of polystyrene.

 Model: Waters e2695 Waters Co., Ltd. product

 Column: One Shodex LF-804

 Measurement conditions: Column pressure 2.7 kPa

 Eluent: Tetrahydrofuran (THF)

 Flow rate: 1 ml / min

 Temperature: 40 ℃

 Detector: UV-Visible Detector 2489

         WAVE LENGTH: 254nm

 Injection volume: 100μml

 Sample concentration: 5mg / ml

(2) Alkali dissolution rate (DR)

3 g of novolac-type phenol resins were dissolved in 9 g of PGMEA (propylene glycol monomethyl ether acetate), and the resin solution was combined. They were filtered through a 0.2 micro membrane filter. They 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 developer (1.60% aqueous solution of tetramethylammonium hydroxide) was used, and the time until the membrane completely disappeared was measured. The value divided by the time until the initial film thickness was dissolved was taken as the dissolution rate.

(3) Softening point (SP)

It was carried out by measuring the softening point of the circular sphere method based on JIS K6910.

(4) hydroxyl equivalent

It carried out by measuring the hydroxyl group equivalent according to JIS K0070.

[Novolak Type Phenolic Resin (A)]

[Synthesis Example A1] Novolac-type phenol 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 in a 1000 ml glass flask equipped with a thermometer, inlet / outlet and stirrer. ), And 0.7 g of oxalic acid were added, reacted at 100 ° C. for 5 hours, and then heated to 180 ° C. to dehydrate. Thereafter, distillation was performed under reduced pressure at 30 torr for 2 hours to remove unreacted raw materials and the like to obtain 142 g of meta-paracresol novolak-type phenol resin (A1).

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

[Synthesis Example A2] Novolac type phenolic resin (A2)

Meta-paracresol novolak-type phenol 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). 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 group equivalent was 127 g / eq.

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

Meta-paracresol novolac-type phenol 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 / sec, a softening point of 158 ° C, and a hydroxyl group equivalent of 125 g / eq.

[Synthesis Example A4] Novolac type phenolic resin (A4)

The dimer component (n = 0) was reduced by steam distillation of the meta-paracresol novolac type phenol resin A1 obtained in Synthesis Example A1.

The obtained meta-paracresol novolak-type phenol resin (A4) had a weight average molecular weight of 6300, an alkali dissolution rate of 310 Angstroms / 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, 70.9 g (0.99 mol) of 42% formalin, and oxalic acid 0.6 in a glass flask with a capacity of 1000 ml equipped with a thermometer, inlet / outlet and stirrer g was added and reacted at 100 ° C for 5 hours, followed by dehydration by raising the temperature to 180 ° C. Thereafter, distillation was performed under reduced pressure at 30 torr for 2 hours to remove unreacted raw materials and the like, and 144 g of novolac-type phenol resin (A5) was obtained.

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

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

M-cresol 94.7 g (0.88 mol), p-cresol 142.1 g (1.32 mol), o-cresol 26.32 g (0.24 mol), 42% formalin in a 1000 ml glass flask with a thermometer, inlet / outlet and stirrer 116.6 g (1.63 mol), and 0.92 g of oxalic acid were added, reacted at 100 ° C for 10 hours, and then heated to 180 ° C to dehydrate. Thereafter, distillation was performed under reduced pressure at 30 torr for 2 hours to remove unreacted raw materials and the like, thereby obtaining 172 g of cresol novolak-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)

M-cresol 31.6 g (0.29 mol), p-cresol 126.5 g (1.17 mol), resorcin 17.9 g (0.16 mol), 42% formalin 69.74 in a 1000 ml glass flask equipped with a thermometer, inlet / outlet and stirrer g (0.98 mol), and 1.8 g of oxalic acid were added, reacted at 100 ° C for 5 hours, and then heated to 180 ° C to dehydrate. Thereafter, distillation was performed under reduced pressure at 30 torr for 2 hours to remove unreacted raw materials and the like, thereby obtaining 141 g of a novolac-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 phenolic resin (B)]

Novolac type phenolic resin (B1)

A novolak-type phenol resin containing an benzene ring as an arylene skeleton represented by the following general formula (14) in the structure (weight average molecular weight: 1200, alkali dissolution rate: 4861 Angstroms / sec, softening point: 65 ° C, hydroxyl group equivalent: 175 g / eq).

[Formula 21]

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

Novolac type phenolic resin (B2)

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

Novolac type phenolic resin (B3)

A novolac-type phenol resin containing a biphenyl ring in the structure as an arylene skeleton represented by the following general formula (15) (weight average molecular weight: 1070, alkali dissolution rate: 828 angstroms / sec, softening point: 66 ° C, hydroxyl group equivalent: 203 g / eq).

[Formula 22]

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

Novolac type phenolic resin (B4)

A novolac-type phenol resin containing a biphenyl ring in the structure as an arylene skeleton represented by the general formula (15) (weight average molecular weight: 1400, alkali dissolution rate: 95 angstroms / sec, softening point: 73 ° C, hydroxyl group equivalent: 206 g / eq).

Novolac type phenolic resin (B5)

A novolac-type phenol resin containing a naphthalene skeleton as a structure of an arylene skeleton represented by the following general formula (16) (weight average molecular weight: 730, alkali dissolution rate: 5768 Angstroms / sec, softening point: 114, hydroxyl group equivalent: 143 g / eq).

[Formula 23]

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

Table 1 shows the summary of the novolac-type phenolic resin (A) and the novolac-type phenolic resin (B).

[2] phenolic resin composition for photoresist, photoresist composition

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

Meanwhile, an analysis method and an evaluation method of the phenol resin composition for photoresist and the photoresist composition are as follows.

<Phenol composition for photoresist>

(1) The weight average molecular weight (Mw), (2) alkali dissolution rate (DR), and (3) softening point (SP) were performed by the same method as the analytical method or evaluation method of the novolac-type phenol resin. .

<Photoresist composition>

(1) Sensitivity, residual ratio, and 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 15000 mm thick coating film. Thereafter, a reduction projection exposure apparatus was used, the exposure time was changed stepwise, and an optimal exposure amount was confirmed, followed by exposure to an optimal exposure amount. Subsequently, a developer (2.38% tetramethylammonium hydroxide aqueous solution) was used, developed for 60 seconds, and rinsed and dried.

Sensitivity

Sensitivity was evaluated by 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 below 5 mJ / cm 2.

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

Residual rate

The residual film ratio was determined from the residual film thickness of the 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 using the test chart mask and the following criteria.

◎: 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

For the resist film on which the positive pattern was obtained, CF ₄ was used as an etching gas, dry etching was performed using an etching apparatus at an etching condition of 0.7 sccm, 80 W, and the thickness of the resist pattern was measured by measuring the film thickness before and after etching. I got the rate. The result was compared with the etching rate when only the novolac-type phenol resin (A) was used as the phenol resin composition for photoresists.

The ratio of the etching rate of the novolac-type phenolic resin composition for photoresists to the novolac-type phenolic resin (A) used in the novolac-type phenolic resin compositions for photoresist ([Novolac-type phenolic resin for photoresist] Etching rate] / [Etching rate in the case of only a novolac type phenol resin (A)] was evaluated based on the following criteria.

◎: When less than 0.75

○: 0.75 or more to 0.90 or less

×: when it exceeds 0.90

[Example 1]

The novolac-type phenol resin (A2) obtained in Synthesis Example A2 and the novolac-type phenol resin (B1) obtained in Synthesis Example B1 were melt-mixed to adjust the phenol resin composition for photoresists. Specifically, 70 g of a novolac-type phenolic resin (A2) and 30 g of a novolac-type phenolic resin (B1) were mixed into a 500 ml glass flask equipped with a thermometer, an inlet / outlet, and a stirrer, in the composition shown in Table 1 below. A phenol resin composition for photoresist was prepared by melt mixing under a temperature condition of 185 ° C.

The obtained photoresist phenol resin composition had a weight average molecular weight of 3300, an alkali dissolution rate of 1210 Angstroms / sec, and a softening point of 139 ° C.

Table 2 shows the results of evaluating the properties of the phenol resin composition for photoresist.

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

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

(Examples 2 to 10, Comparative Examples 1 to 12)

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

Table 2 shows the results of evaluating the properties of the obtained phenol resin composition for photoresists.

Next, using the obtained phenol resin composition for photoresists, 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 apparent from the results shown in Table 2, it was found that the photoresist composition obtained in each example had high developability such as high sensitivity, high residual film rate, and high resolution, and further excellent 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 was compared with the case where the novolac-type phenol resin A3 of Comparative Example 3 was used alone. It can be seen that the dry etching property is improved.

In addition, it can be seen from the comparison of Example 2 and Comparative Example 8 that the resist composition of Example 2 has an improved residual film rate compared to 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 is the resolution of Example 2, although the resolution of Comparative Example 3 is ○ and the resolution of Comparative Example 8 is x. It can be seen that is improved by ◎.

Claims (4)

The mass ratio of (A) and (B) of the novolak-type phenol resin (B) containing at least one of the novolak-type phenol resin (A) represented by the following general formula (1) and the arylene skeleton and the naphthalene skeleton in the structure A phenol resin composition for photoresists, characterized in that it is contained in an amount of 5 to 95:95 to 5.
[Formula 1]

(In the general formula (1), R ₁ represents hydrogen or a straight or branched alkyl group having 1 to 8 carbon atoms, and may be the same or different. However, at least one of R ₁ has 1 to 8 carbon atoms. Is a straight-chain or branched alkyl group, p is 1 or more and 3 or less, and may be the same or different, q is 1 or more and 3 or less, and may be the same or different, but p + q≤4, where n is 0 The above integer is represented.) According to claim 1,
A phenol resin composition for photoresists, wherein the novolac-type phenol resin (B) contains a unit represented by the following general formula (4) in the structure.
[Formula 2]

(In General Formula (4), X represents a divalent group represented by the following Formula (4-1) or (4-2)).
[Formula 3]

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, respectively. However, a + b≤4. On the other hand, when a plurality of units represented by formula (4) are included in the structure of the novolac-type phenol resin (B), a plurality of a, b and R ₂ included in the structure of the novolac-type phenol resin (B) are each It may be the same or different.) According to claim 1,
A phenol resin composition for photoresists, wherein the novolac-type phenol resin (B) contains a unit represented by the following general formula (10) in the structure.
[Formula 4]

(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, an alkoxy group, an acetyl group, or 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, R ₃ may be the same or different, respectively. When a plurality of units represented by the general formula (10) are included in the structure of the resin (B), the plurality of c, R ₄ and R ₃ contained in the structure of the novolac-type phenol resin (B) may be the same or different, respectively. ) A photoresist composition comprising the phenolic resin composition for photoresists according to any one of claims 1 to 3 and a photosensitizer.