KR102467637B1 - resist composition - Google Patents

Abstract

(상기 식(1) 중, R₁ 및 R₂는, 각각 독립으로, 수소 원자, 탄소 원자수 1∼9의 지방족 탄화수소기, 알콕시기, 아릴기, 아랄킬기 또는 할로겐 원자를 나타낸다.
m 및 n은, 각각 독립으로, 0∼4의 정수를 나타낸다.
R₁이 복수 있을 경우, 복수의 R₁은 서로 같아도 되고 달라도 된다.
R₂가 복수 있을 경우, 복수의 R₂는 서로 같아도 되고 달라도 된다.
R₃은, 수소 원자, 탄소 원자수 1∼9의 지방족 탄화수소기, 또는 탄화수소기 상에 알콕시기, 할로겐기 및 수산기에서 선택되는 치환기를 1 이상 갖는 구조 부위를 나타낸다)It is an object of the present invention to provide a resist composition that has high heat resistance and can be used for lithography using electron beams and extreme ultraviolet rays. Specifically, a resist composition containing a metal salt of a novolak-type phenolic resin (C) containing an aromatic compound (A) represented by the following formula (1) and an aliphatic aldehyde (B) as essential reaction raw materials is used.

(In the formula (1), R ₁ and R ₂ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 9 carbon atoms, an alkoxy group, an aryl group, an aralkyl group, or a halogen atom.
m and n each independently represents an integer of 0 to 4.
When there are a plurality of R ₁ 's, the plurality of R ₁ 's may be the same as or different from each other.
When there are a plurality of R ₂ , the plurality of R ₂ may be the same or different.
R ₃ represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 9 carbon atoms, or a structural site having at least one substituent selected from an alkoxy group, a halogen group and a hydroxyl group on the hydrocarbon group)

Description

resist composition

The present invention relates to a resist composition.

A resist used in the manufacture of semiconductors such as IC and LSI, manufacture of display devices such as LCD, and manufacture of printing original plates, etc. Positive type photoresist using alkali-soluble resin and photosensitizer such as 1,2-naphthoquinonediazide compound is known As the alkali-soluble resin, a positive photoresist composition using a mixture of m-cresol novolac resin and p-cresol novolac resin as the alkali-soluble resin has been proposed (see Patent Document 1, for example).

The positive type photoresist composition described in Patent Literature 1 was developed for the purpose of improving developability such as sensitivity, but in recent years, high integration of semiconductors has increased, patterns tend to become thinner, and more excellent sensitivity has been demanded. . However, in the positive type photoresist composition described in Patent Literature 1, there was a problem that sufficient sensitivity corresponding to thinning was not obtained. In addition, since various heat treatments are performed in manufacturing processes of semiconductors and the like, high heat resistance is also required, but the positive photoresist composition described in Patent Literature 1 has a problem of not having sufficient heat resistance.

Further, in particular, in the field of semiconductor manufacturing, such as ICs and LSIs, finer processing is required, and lithography using electron beams or extreme ultraviolet (EUV) is being studied. Along with the shortening of the wavelength of the exposure light source, further improvement in the properties of the resist composition corresponding to this has been demanded.

Japanese Patent Laid-Open No. 2-55359

An object to be solved by the present invention is to provide a resist composition that has high heat resistance and can be used for lithography using electron beams and extreme ultraviolet rays.

As a result of intensive studies to solve the above problems, the present inventors have found that a resist composition containing a metal salt structure of a novolak-type phenolic resin obtained by reacting a trinuclear phenolic compound containing a carboxylic acid with a specific structure with an aliphatic aldehyde, It was found that it had high heat resistance and could be used for lithography using electron beams and extreme ultraviolet rays, and the present invention was completed.

That is, the present invention relates to a resist composition comprising a metal salt of a novolak-type phenolic resin (C) containing an aromatic compound (A) represented by the following formula (1) and an aliphatic aldehyde (B) as essential reaction raw materials .

(In the formula (1), R ₁ and R ₂ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 9 carbon atoms, an alkoxy group, an aryl group, an aralkyl group, or a halogen atom.

m and n each independently represents an integer of 0 to 4.

When there are a plurality of R ₁ 's, the plurality of R ₁ 's may be the same as or different from each other.

When there are a plurality of R ₂ , the plurality of R ₂ may be the same or different.

R ₃ represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 9 carbon atoms, or a structural site having at least one substituent selected from an alkoxy group, a halogen group and a hydroxyl group on the hydrocarbon group)

According to the present invention, it is possible to provide a resist composition that has high heat resistance and can be used for lithography using electron beams and extreme ultraviolet rays.

1 is a GPC chart of a precursor compound obtained in Synthesis Example 1;
2 is a ¹³ C-NMR chart of the precursor compound obtained in Synthesis Example 1;
3 is a GPC chart of the precursor compound obtained in Synthesis Example 2;
4 is a ¹³ C-NMR chart of the precursor compound obtained in Synthesis Example 2;
5 is a GPC chart of the novolak-type phenolic resin obtained in Production Example 1;
6 is a GPC chart of the novolac-type phenolic resin obtained in Production Example 2;
7 is a GPC chart of the novolak resin obtained in Preparation Example 3;
8 is a GPC chart of the novolak resin obtained in Production Example 4;

Hereinafter, one embodiment of the present invention will be described. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within a range not impairing the effects of the present invention.

[resist composition]

The resist composition of the present invention contains a metal salt of a novolac-type phenolic resin (C) containing an aromatic compound (A) represented by the following formula (1) and an aliphatic aldehyde (B) as essential reaction raw materials.

(In the formula (1), R ₁ and R ₂ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 9 carbon atoms, an alkoxy group, an aryl group, an aralkyl group, or a halogen atom.

m and n each independently represents an integer of 0 to 4.

When there are a plurality of R ₁ 's, the plurality of R ₁ 's may be the same as or different from each other.

When there are a plurality of R ₂ , the plurality of R ₂ may be the same or different.

R ₃ represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 9 carbon atoms, or a structural site having at least one substituent selected from an alkoxy group, a halogen group and a hydroxyl group on the hydrocarbon group)

A resist composition usually contains a resin whose polarity changes by being decomposed by the action of acid (acid-decomposable resin) and a compound that generates acid when irradiated with light (photoacid generator). In such a resist composition, the photoacid generator generates acid upon exposure to light, and the action of the generated acid changes the polarity of the resin, thereby forming a desired pattern. However, there are cases in which the resolution of the formed pattern is insufficient because of a mechanism such as diffusion of acid that tends to cause non-uniformity.

In the resist composition of the present invention, a desired pattern is formed by decomposing the metal salt structure upon exposure to release metal ions and changing the polarity of the novolak-type phenolic resin (C). High resolution can be obtained in the resist composition of the present invention, which does not involve a mechanism such as diffusion of acid that tends to cause non-uniformity. Particularly in exposure using short-wavelength light such as electron beams and extreme ultraviolet light, resolution and irregularities in the pattern shape tend to cause problems, but the resist composition of the present invention can solve these problems.

In the metal salt of the novolac-type phenolic resin (C), some or all of the functional groups of the novolak-type phenolic resin (C) may have a metal salt structure.

The metal salt of the novolak-type phenolic resin (C) is preferably a carboxylic acid metal salt of the novolak-type phenolic resin (C). The metal carboxylic acid salt of the novolac-type phenolic resin (C) preferably has a structure represented by the following formula (X).

(In the above formula (X),

R ₁ , R ₂ , R ₃ , m and n are the same as R ₁ , R ₂ , R ₃ , m and n in the formula (1).

* is a bonding point with any one of the three aromatic rings in the above formula (1), and the two * may be bonded to the same aromatic ring or may be bonded to different aromatic rings.

Met represents a metal atom.

n represents an integer greater than or equal to 1)

Regarding the structure represented by the formula (X), for example, when the valence of the metal atom is 1, 2, 3 or 4, the following formulas (X1), (X2), (X3) or (X4) structure to be displayed.

In the resist composition of the present invention, the metal salt structure may be contained in the novolac-type phenolic resin (C), and the content of the metal salt structure in all repeating units of the novolak-type phenolic resin (C) is, for example, For example, it is 1-80 mol%, Preferably it is 10-65 mol%, More preferably, it is 20-50 mol%.

In the resist composition of the present invention, whether or not a metal salt structure of the novolak-type phenol resin (C) is formed is confirmed by the method described in Examples.

Components included in the resist composition of the present invention are described below.

[Novolak-type phenolic resin]

The novolak-type phenolic resin (C) is a resin containing an aromatic compound (A) represented by the following formula (1) and an aliphatic aldehyde (B) as essential reaction raw materials.

(In the formula (1), R ₁ and R ₂ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 9 carbon atoms, an alkoxy group, an aryl group, an aralkyl group, or a halogen atom.

m and n each independently represents an integer of 0 to 4.

When there are a plurality of R ₁ 's, the plurality of R ₁ 's may be the same as or different from each other.

When there are a plurality of R ₂ , the plurality of R ₂ may be the same or different.

R ₃ represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 9 carbon atoms, or a structural site having at least one substituent selected from an alkoxy group, a halogen group and a hydroxyl group on the hydrocarbon group)

In the formula (1), examples of the aliphatic hydrocarbon group having 1 to 9 carbon atoms for R ₁ , R ₂ and R ₃ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a t-butyl group and a hexyl group. , C1-C9 alkyl groups and C3-C9 cycloalkyl groups, such as a cyclohexyl group, a heptyl group, an octyl group, and a nonyl group.

In said Formula (1), a methoxy group, an ethoxy group, a propyloxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a cyclohexyloxy group etc. are mentioned as an alkoxy group of R< ₁ > and R< ₂ >.

In the formula (1), examples of the aryl group for R ₁ and R ₂ include a phenyl group, a tolyl group, a xylyl group, a naphthyl group and an anthryl group.

In the formula (1), examples of the aralkyl group for R ₁ and R ₂ include a benzyl group, a phenylethyl group, a phenylpropyl group, and a naphthylmethyl group.

In the formula (1), examples of the halogen atom for R ₁ and R ₂ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In the above formula (1), the "structural site having at least one substituent selected from an alkoxy group, a halogen group and a hydroxyl group on the hydrocarbon group" of R ₃ is an alkyl halide group, an aryl halide group, and a 2-methoxyethoxy group. , an alkoxyalkoxy group such as a 2-ethoxyethoxy group, an alkylalkoxy group substituted with a hydroxy group, and the like.

In the formula (1), n and m are each preferably an integer of 2 or 3.

When n and m are each 2, it is preferable that the two R ₁ and the two R ₂ are each independently an alkyl group having 1 to 3 carbon atoms. At this time, it is preferable that two R ₁ and two R ₂ are bonded to the 2,5-position of the phenolic hydroxyl group, respectively.

The aromatic compound (A) represented by the formula (1) may be used alone or in a plurality of compounds having different molecular structures.

The aromatic compound (A) represented by the formula (1) can be prepared, for example, by a condensation reaction between an alkyl-substituted phenol (a1) and an aromatic aldehyde (a2) having a carboxy group.

The aromatic compound (A) represented by the formula (1) can be prepared, for example, by a condensation reaction between an alkyl-substituted phenol (a1) and an aromatic ketone (a3) having a carboxyl group.

The alkyl-substituted phenol (a1) is a phenol substituted by an alkyl group, and examples of the alkyl group include an alkyl group having 1 to 8 carbon atoms, and a methyl group is preferable.

Specific examples of the alkyl-substituted phenol (a1) include o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, p-octylphenol, p-t-butylphenol, and o-cyclo monoalkyl phenols such as hexyl phenol, m-cyclohexyl phenol, and p-cyclohexyl phenol; dialkylphenols such as 2,5-xylenol, 3,5-xylenol, 3,4-xylenol, 2,4-xylenol, and 2,6-xylenol; and trialkylphenols such as 2,3,5-trimethylphenol and 2,3,6-trimethylphenol. Among these, dialkyl phenol is preferable, and 2,5-xylenol and 2,6-xylenol are more preferable. Alkyl-substituted phenol (a1) may be used individually by 1 type, and may use 2 or more types together.

Aromatic aldehyde (a2) having a carboxyl group is a compound having a formyl group on an aromatic nucleus, such as benzene, naphthalene, phenol, resorcin, naphthol, dihydroxynaphthalene, etc., and also an alkyl group, an alkoxy group, a halogen atom, etc. compounds with

Specific examples of the aromatic aldehyde (a2) having a carboxy group include 4-formylbenzoic acid, 2-formylbenzoic acid, 3-formylbenzoic acid, methyl 4-formylbenzoate, ethyl 4-formylbenzoate, and propyl 4-formylbenzoate. , 4-formylbenzoate isopropyl, 4-formylbenzoate isobutyl, 4-formylbenzoate isobutyl, 4-formylbenzoate tertiary butyl, 4-formylbenzoate cyclohexyl, 4-formylbenzoate tertiary octyl, etc. can be heard Among these, 4-formylbenzoic acid is preferable. The aromatic aldehyde (a2) having a carboxyl group may be used singly or in combination of two or more.

The aromatic ketone (a3) having a carboxy group is a compound having at least one carboxy group or an ester derivative thereof and a carbonyl group on an aromatic ring.

Specific examples of the aromatic ketone (a3) having a carboxyl group include, for example, 2-acetylbenzoic acid, 3-acetylbenzoic acid, 4-acetylbenzoic acid, methyl 2-acetylbenzoate, ethyl 2-acetylbenzoate, propyl 2-acetylbenzoate, 2-acetylbenzoate isopropyl, 2-acetylbenzoate isobutyl, 2-acetylbenzoate isobutyl, 2-acetylbenzoate tertiary butyl, 2-acetylbenzoate cyclohexyl, 2-acetylbenzoate tertiary octyl, etc. are mentioned. Among these, 2-acetylbenzoic acid and 4-acetylbenzoic acid are preferred.

The aromatic ketone (a3) may be used singly or in combination of two or more.

Specific examples of the aliphatic aldehyde (B) include formaldehyde, paraformaldehyde, 1,3,5-trioxane, acetaldehyde, propionaldehyde, tetraoxymethylene, polyoxymethylene, chloral, hexamethylenetetramine, furfural, glyoxal, n-butylaldehyde, caproaldehyde, allylaldehyde, crotonaldehyde, acrolein, and the like. The aliphatic aldehyde compound (B) may be used alone or in combination of two or more.

Aliphatic aldehyde (B) is preferably formaldehyde.

When formaldehyde and an aliphatic aldehyde other than formaldehyde are used as the aliphatic aldehyde (B), the amount of the aliphatic aldehyde other than formaldehyde is preferably in the range of 0.05 to 1 mole per mole of formaldehyde.

The method for producing the novolak-type phenolic resin (C) preferably includes the following three steps 1 to 3.

(Process 1)

An aromatic compound (A) is obtained by heating an alkyl-substituted phenol (a1) and an aromatic aldehyde (a2) having a carboxy group in the presence of an acid catalyst in the range of 60 to 140° C. using a solvent as necessary to polycondensate .

(Process 2)

The aromatic compound (A) obtained in Step 1 is isolated from the reaction solution.

(Process 3)

A novolac-type phenolic resin ( C) get

Examples of the acid catalyst used in the steps 1 and 3 include acetic acid, oxalic acid, sulfuric acid, hydrochloric acid, phenolsulfonic acid, p-toluenesulfonic acid, zinc acetate, and manganese acetate. These acid catalysts may be used alone or in combination of two or more. Moreover, among these acid catalysts, sulfuric acid and p-toluenesulfonic acid are preferable in step 1, and sulfuric acid, oxalic acid and zinc acetate are preferable in step 3, in view of their excellent activity. In addition, the acid catalyst may be added before the reaction or may be added during the reaction.

As a solvent used as needed in the said process 1 and process 3, For example, monoalcohol, such as methanol, ethanol, a propanol; Ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol polyols such as 1,9-nonanediol, trimethylene glycol, diethylene glycol, polyethylene glycol, and glycerin; 2-ethoxyethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monopentyl ether, ethylene glycol dimethyl ether, ethylene glycol ethylmethyl ether, ethylene glycol mono glycol ethers such as phenyl ether; cyclic ethers such as 1,3-dioxane and 1,4-dioxane; glycol esters such as ethylene glycol acetate; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; Aromatic hydrocarbons, such as toluene and xylene, etc. are mentioned. These solvents may be used alone or in combination of two or more. Moreover, among these solvents, 2-ethoxyethanol is preferable from the viewpoint of excellent solubility of the obtained compound.

The input ratio [(a1)/(a2)] of the alkyl-substituted phenol (a1) and the aromatic aldehyde (a2) having a carboxy group in step 1 is the removability of the unreacted alkyl-substituted phenol (a1) and the yield of the product and since the purity of the reaction product is excellent, the molar ratio is preferably in the range of 1/0.2 to 1/0.5, and more preferably in the range of 1/0.25 to 1/0.45.

The addition ratio [(A)/(B)] of the aromatic compound (A) and the aliphatic aldehyde (B) in step 3 can suppress excessive high molecular weight (gelation) and is suitable as a phenolic resin for resists. Since a molecular weight is obtained, the molar ratio is preferably in the range of 1/0.5 to 1/1.2, and more preferably in the range of 1/0.6 to 1/0.9.

As a method for isolating the aromatic compound (A) from the reaction solution in Step 2, for example, the reaction solution is injected into a poor solvent (S1) in which the reaction product is insoluble or sparingly soluble, and the resulting precipitate is filtered. After fractionation, a method of dissolving the reaction product, dissolving it in a solvent (S2) that is also miscible with the poor solvent (S1), then introducing it into the poor solvent (S1) and separating the resulting precipitate by filtration is exemplified.

Examples of the poor solvent (S1) used at this time include water; Monoalcohols, such as methanol, ethanol, and a propanol; aliphatic hydrocarbons such as n-hexane, n-heptane, n-octane, and cyclohexane; Aromatic hydrocarbons, such as toluene and xylene, are mentioned. Among these poor solvents (S1), water and methanol are preferable because the acid catalyst can be efficiently removed at the same time. On the other hand, examples of the solvent (S2) include monoalcohols such as methanol, ethanol, and propanol; Ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol polyols such as 1,9-nonanediol, trimethylene glycol, diethylene glycol, polyethylene glycol, and glycerin; 2-ethoxyethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monopentyl ether, ethylene glycol dimethyl ether, ethylene glycol ethylmethyl ether, ethylene glycol mono glycol ethers such as phenyl ether; cyclic ethers such as 1,3-dioxane and 1,4-dioxane; glycol esters such as ethylene glycol acetate; Ketones, such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, etc. are mentioned. In addition, when water is used as the poor solvent (S1), acetone is preferable as the (S2). In addition, each of the poor solvent (S1) and the solvent (S2) may be used alone or in combination of two or more.

When an aromatic hydrocarbon such as toluene or xylene is used as the solvent in steps 1 and 3, when heated to 80° C. or higher, the aromatic compound (A) generated by the reaction dissolves in the solvent, so it is cooled as it is Since crystals of the aromatic compound (A) precipitate by doing so, the aromatic compound (A) can be isolated by filtration. In this case, it is not necessary to use the poor solvent (S1) and the solvent (S2).

The aromatic compound (A) represented by the formula (1) can be obtained by the isolation method in Step 2 described above. The purity of the aromatic compound (A) is preferably 90% or more, more preferably 94% or more, and particularly preferably 98% or more, as calculated from a gel permeation chromatography (GPC) chart. The purity of the aromatic compound (A) can be obtained from the area ratio of the GPC chart, and is measured under the measurement conditions described later.

The weight average molecular weight (Mw) of the novolac-type phenolic resin (C) is preferably in the range of 2,000 to 35,000, and more preferably in the range of 2,000 to 25,000. The weight average molecular weight (Mw) of the novolak-type phenolic resin (C) was measured under the following measurement conditions using gel permeation chromatography (hereinafter abbreviated as "GPC").

(GPC measurement conditions)

Measuring device: "HLC-8220 GPC" manufactured by Tosoh Corporation

Column: Showa Denko Co., Ltd. "Shodex KF802" (8.0 mmФ × 300 mm)

+ "Shodex KF802" (8.0 mmФ × 300 mm) manufactured by Showa Denko Co., Ltd.

+ "Shodex KF803" (8.0 mmФ × 300 mm) manufactured by Showa Denko Co., Ltd.

+ "Shodex KF804" (8.0 mmФ × 300 mm) manufactured by Showa Denko Co., Ltd.

Column temperature: 40°C

Detector: RI (Differential Refractometer)

Data processing: "GPC-8020 Model II Version 4.30" manufactured by Tosoh Corporation

Developing solvent: tetrahydrofuran

Flow rate: 1.0 mL/min

Sample: A 0.5% by mass tetrahydrofuran solution in terms of resin solid content filtered through a microfilter (100 μl)

Standard sample: the following monodisperse polystyrene

(Standard sample: monodisperse polystyrene)

"A-500" made by Tosoh Corporation

"A-2500" by Tosoh Corporation

"A-5000" manufactured by Toso Co., Ltd.

"F-1" made by Toso Co., Ltd.

"F-2" made by Toso Co., Ltd.

"F-4" made by Toso Co., Ltd.

"F-10" made by Toso Co., Ltd.

"F-20" made by Toso Co., Ltd.

[Metal atom forming metal salt]

Examples of metal atoms that form a metal salt with the novolak-type phenolic resin (C) include calcium, zinc, copper, iron, aluminum, zirconium, hafnium, titanium, indium, and tin. Among these, calcium, zinc, copper, iron, zirconium, hafnium and tin are preferable. The said metal atom may be used individually by 1 type, and may use 2 or more types together.

The metal salt of the novolac-type phenolic resin (C) is formed by adding a metal salt such as a hydrochloride, nitrate, or sulfate salt of a metal atom and/or a metal oxide while heating a composition containing the novolak-type phenolic resin (C). can do. Of these, nitrates and/or metal oxides are preferred.

The amount of the metal salt and/or metal oxide added is, for example, 1 to 100 parts by mass, preferably 10 to 50 parts by mass, based on 100 parts by mass of the novolak-type phenolic resin (C).

[Alkali-soluble resin]

In the resist composition of the present invention, the novolak-type phenolic resin (C) is an alkali-soluble resin, but an alkali-soluble resin (D) other than the novolak-type phenolic resin (C) may also be included.

Alkali-soluble resin (D) should just be resin soluble in aqueous alkali solution, and a cresol novolac resin is preferable. The cresol novolak resin is a novolac-type phenolic resin obtained by condensing a phenolic compound and an aldehyde compound as reaction raw materials, preferably 1 selected from the group consisting of o-cresol, m-cresol and p-cresol. It is a resin which uses the above phenolic compound as an essential reaction raw material.

As a phenolic compound serving as a reaction raw material for the cresol novolac resin, a phenol or a phenol derivative other than cresol may be used in combination. Examples of phenolic compounds other than cresol include phenol; 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, etc. ilenol; ethyl phenols such as o-ethyl phenol, m-ethyl phenol, and p-ethyl phenol; butyl phenols such as isopropyl phenol, butyl phenol, and p-t-butyl phenol; alkylphenols such as p-pentylphenol, p-octylphenol, p-nonylphenol, and p-cumylphenol; halogenated phenols such as fluorophenol, chlorophenol, bromophenol, and iodophenol; monosubstituted phenols such as p-phenylphenol, aminophenol, nitrophenol, dinitrophenol, and trinitrophenol; condensed polycyclic phenols such as 1-naphthol and 2-naphthol; polyhydric phenols such as resorcin, alkylresorcin, pyrogallol, catechol, alkylcatechol, hydroquinone, alkylhydroquinone, phloroglucine, bisphenol A, bisphenol F, bisphenol S, and dihydroxynaphthalin; can Phenolic compounds other than the cresol may be used alone or in combination of two or more.

When using cresol and a phenolic compound other than cresol as a reaction raw material for preparation of the alkali-soluble resin (D), the amount of the phenolic compound other than cresol used is preferably in the range of 0.05 to 1.0 mol with respect to 1.0 mol of cresol. .

Examples of the aldehyde compound used as a raw material of the cresol novolac resin include formaldehyde, paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, polyoxymethylene, chloral, hexamethylenetetramine, furfural, and glyoxal , n-butylaldehyde, caproaldehyde, allylaldehyde, benzaldehyde, crotonaldehyde, acrolein, tetraoxymethylene, phenylacetaldehyde, o-tolualdehyde, salicylaldehyde, and the like. Among these, formaldehyde is preferred. The said aldehyde compound may be used individually by 1 type, and may use 2 or more types together.

When formaldehyde is used as an aldehyde compound used as a raw material for the cresol novolac resin, an aldehyde compound other than formaldehyde may be used. When formaldehyde and an aldehyde compound other than formaldehyde are used as reaction raw materials for the preparation of the cresol novolac resin, the amount of the aldehyde compound other than formaldehyde used is in the range of 0.05 to 1.0 mole relative to 1.0 mole of the formaldehyde desirable.

The condensation reaction between the phenolic compound and the aldehyde compound is preferably carried out in the presence of an acid catalyst. Examples of the acid catalyst include oxalic acid, sulfuric acid, hydrochloric acid, phenolsulfonic acid, p-toluenesulfonic acid, zinc acetate, and manganese acetate. Among these, oxalic acid is preferable because of its excellent catalytic activity. The said acid catalyst may be used individually by 1 type, and may use 2 or more types together. The acid catalyst may be added before the reaction, may be added during the reaction, or may be either.

The addition ratio (molar ratio) of the phenolic compound to the aldehyde compound in preparing the cresol novolac resin is preferably in the range of 0.3 to 1.6, more preferably in the range of 0.5 to 1.3, in terms of aldehyde compound/phenolic compound. do.

As a specific example of the reaction between the phenolic compound and the aldehyde compound in preparing the cresol novolak resin, the phenolic compound and the aldehyde compound are heated at 60 to 140 ° C. in the presence of an acid catalyst to advance the polycondensation reaction, and then reduced pressure Methods of performing dehydration and depilation under conditions are exemplified.

The resist composition of the present invention may or may not contain a photosensitizer (E). As the photosensitizer (E), a compound having a quinonediazide group can be used. Examples of the compound having the quinonediazide group include 2,3,4-trihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone, 2,3,6-trihydroxybenzophenone, 2,3,4-trihydroxy-2'-methylbenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,2',4 ,4'-tetrahydroxybenzophenone, 2,3',4,4',6-pentahydroxybenzophenone, 2,2',3,4,4'-pentahydroxybenzophenone, 2,2' ,3,4,5-pentahydroxybenzophenone, 2,3',4,4',5',6-hexahydroxybenzophenone, 2,3,3',4,4',5'-hexa polyhydroxybenzophenone-based compounds such as hydroxybenzophenone; bis(2,4-dihydroxyphenyl)methane, bis(2,3,4-trihydroxyphenyl)methane, 2-(4-hydroxyphenyl)-2-(4'-hydroxyphenyl)propane, 2-(2,4-dihydroxyphenyl)-2-(2',4'-dihydroxyphenyl)propane, 2-(2,3,4-trihydroxyphenyl)-2-(2', 3',4'-trihydroxyphenyl)propane, 4,4'-{1-[4-[2-(4-hydroxyphenyl)-2-propyl]phenyl]ethylidene}bisphenol, 3,3' -Bis[(poly)hydroxyphenyl]alkane compounds such as dimethyl-{1-[4-[2-(3-methyl-4-hydroxyphenyl)-2-propyl]phenyl]ethylidene}bisphenol; Tris(4-hydroxyphenyl)methane, bis(4-hydroxy-3,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-4-hydroxy hydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-2-hydroxyphenylmethane, bis( Tris such as 4-hydroxy-2,5-dimethylphenyl)-3,4-dihydroxyphenylmethane and bis(4-hydroxy-3,5-dimethylphenyl)-3,4-dihydroxyphenylmethane (hydroxyphenyl)methanes or their methyl substituents; Bis(3-cyclohexyl-4-hydroxyphenyl)-3-hydroxyphenylmethane, bis(3-cyclohexyl-4-hydroxyphenyl)-2-hydroxyphenylmethane, bis(3-cyclohexyl-4 -Hydroxyphenyl) -4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2 -Methylphenyl)-3-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-4-hydroxyphenylmethane, bis(3-cyclohexyl-2-hydroxyphenyl)-3 -Hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-3-methylphenyl)-4-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-3-methylphenyl)-3-hydroxy hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-3-methylphenyl)-2-hydroxyphenylmethane, bis(3-cyclohexyl-2-hydroxyphenyl)-4-hydroxyphenylmethane, bis (3-cyclohexyl-2-hydroxyphenyl)-2-hydroxyphenylmethane, bis(5-cyclohexyl-2-hydroxy-4-methylphenyl)-2-hydroxyphenylmethane, bis(5-cyclohexyl Bis(cyclohexylhydroxyphenyl)(hydroxyphenyl)methanes such as -2-hydroxy-4-methylphenyl)-4-hydroxyphenylmethane or their methyl substituents, and naphthoquinone-1,2-diazide -5-sulfonic acid or naphthoquinone-1,2-diazide-4-sulfonic acid, orthoanthraquinonediazide sulfonic acid and the like, complete ester compounds, partial ester compounds, amides or sulfonic acids having a quinonediazide group; A partial amidide etc. are mentioned. These photosensitizers (E) may be used alone or in combination of two or more.

The content of the photosensitizer (E) in the resist composition of the present invention is 3, relative to the total of 100 parts by mass of the novolak-type phenolic resin (C) and the alkali-soluble resin (D), since good sensitivity and a desired pattern can be obtained. The range of to 50 parts by mass is preferable, and the range of 5 to 30 parts by mass is more preferable.

The resist composition of the present invention preferably contains a solvent (F). Examples of the solvent (F) include ethylene glycol alkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether; diethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, and diethylene glycol dibutyl ether; ethylene glycol alkyl ether acetates such as methyl cellosolve acetate and ethyl cellosolve acetate; propylene glycol alkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and propylene glycol monopropyl ether acetate; Ketones, such as acetone, methyl ethyl ketone, cyclohexanone, and methyl amyl ketone; cyclic ethers such as dioxane; 2-Hydroxymethylpropionate, 2-hydroxyethylpropionate, 2-hydroxy-2-methylethylpropionate, ethoxyethyl acetate, oxyacetate ethyl, 2-hydroxy-3-methylbutanoic acid methyl, 3-methoxy and esters such as butyl acetate, 3-methyl-3-methoxybutyl acetate, ethyl formate, ethyl acetate, butyl acetate, methyl acetoacetate, and ethyl acetoacetate. These solvents (F) may be used alone or in combination of two or more.

The content of the solvent (F) in the resist composition of the present invention is such that a uniform coating film can be obtained by a coating method such as a spin coating method for fluidity of the composition, so that the solid content concentration in the resist composition of the present invention is 15 to 65 mass%. It is desirable to do so.

The resist composition of the present invention may contain a metal salt of a novolak-type phenolic resin (C), optionally an alkali-soluble resin (D), a photosensitizer (E), and a solvent (F), and the novolac-type phenolic resin (C) metal salt, and optionally alkali-soluble resin (D), photosensitizer (E), solvent (F), and components other than components (C) to (F) (for example, fillers, pigments, surfactants such as leveling agents, adhesion improvers, at least one selected from dissolution accelerators) may be included, and unavoidable impurities may be included within a range not impairing the effects of the present invention.

In the resist composition of the present invention, for example, 80% by mass or more, 90% by mass or more, 95% by mass or more, 98% by mass or more, or 100% by mass of the solid content after removing the solvent (F) is a novolak-type phenolic resin It may consist of components other than the metal salt of (C), and optionally alkali-soluble resin (D), photosensitizer (E), and components (C)-(F).

The resist composition of the present invention comprises a novolac-type phenolic resin (C), a metal salt, another alkali-soluble resin (D) optionally blended, a photosensitizer (E) and a solvent (F), and various additives added as necessary by conventional methods. In this way, it can be prepared by stirring and mixing to obtain a uniform liquid.

When blending solid materials such as fillers and pigments into the resist composition of the present invention, it is preferable to disperse and mix using a dispersing device such as a dissolver, homogenizer, or three roll mill. Further, the composition may be filtered using a mesh filter, a membrane filter or the like to remove granules and impurities.

[Pattern formation method]

The resist composition of the present invention can be used as either a negative photoresist composition or a positive photoresist. A method for producing a pattern using the resist composition of the present invention includes a step of forming a resist film using the resist composition of the present invention, a step of exposing the resist film, and developing the exposed resist film using a developer to form a pattern. Including the forming process.

Formation of the resist film, exposure of the resist film, and development of the exposed resist film can be performed by known methods. Examples of the light source for exposing the resist composition of the present invention include infrared light, visible light, ultraviolet light, far ultraviolet light, X-rays, and electron beams. Among these light sources, ultraviolet light is preferable, and g-line (wavelength 436 nm), i-line (wavelength 365 nm), and EUV laser (wavelength 13.5 nm) of a high-pressure mercury lamp are suitable.

As an alkaline developing solution used for image development after exposure, For example, Inorganic alkaline substances, such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia; primary amines such as ethylamine and n-propylamine; secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide; Alkaline aqueous solutions, such as cyclic amines, such as pyrrole and piperidine, can be used. Alcohol, surfactant, etc. can also be added to these alkaline developing solutions suitably and used as needed. The alkali concentration of the alkaline developing solution is usually preferably in the range of 2 to 5% by mass, and a 2.38% by mass aqueous solution of tetramethylammonium hydroxide is generally used.

The pattern formation method of this invention is suitably used in the manufacturing process of an electronic device. Examples of the electronic devices include home electric devices, office automation devices, media-related devices, optical devices, communication devices, and the like.

(Example)

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

Synthesis Example 1 Synthesis of phenolic trinuclear compound containing carboxylic acid

293.2 g (2.4 mol) of 2,5-xylenol and 150 g (1 mol) of 4-formylbenzoic acid were put into a 2000 ml four-necked flask equipped with a cooling tube, and dissolved in 500 ml of acetic acid. After adding sulfuric acid 5ml while cooling in an ice bath, it heated to 100 degreeC with the mantle heater, and was made to react, stirring for 2 hours. After completion of the reaction, water was added to the obtained solution to reprecipitate the crude product. The crude product was redissolved in acetone, further reprecipitated with water, and then the precipitate was separated by filtration and vacuum dried to obtain 283 g of pale pink crystals of precursor compound (A-1).

As a result of performing ¹³ C-NMR measurement on the obtained precursor compound (A-1), it was confirmed that it was a compound represented by the following structural formula. In addition, the purity calculated from the GPC chart diagram (GPC purity) was 95.3%. The GPC chart of the precursor compound (A-1) is shown in Fig. 1 and the ¹³ C-NMR chart is shown in Fig. 2 .

Synthesis Example 2 Synthesis of phenolic trinuclear compound

293.2 g (2.4 mol) of 2,5-xylenol and 122 g (1 mol) of 2-hydroxybenzaldehyde were added to a 2000 ml four-necked flask equipped with a cooling tube, and dissolved in 500 ml of 2-ethoxyethanol. After adding 10 ml of sulfuric acid while cooling in an ice bath, it was heated to 100 degreeC with a mantle heater and reacted stirring for 2 hours. After completion of the reaction, water was added to the resulting solution to reprecipitate the crude product. The crude product was redissolved in acetone and further reprecipitated with water, and then the precipitate was separated by filtration and vacuum dried to obtain 283 g of a precursor compound (A'-2) as white crystals.

As a result of performing ¹³ C-NMR measurement on the obtained precursor compound (A'-2), it was confirmed that it was a compound represented by the following structural formula. In addition, the purity calculated from the GPC chart diagram (GPC purity) was 98.2%. The GPC chart of the precursor compound (A′-2) is shown in FIG. 3 and the ¹³ C-NMR chart is shown in FIG.

Production Example 1 Synthesis of carboxylic acid-containing novolak-type phenolic resin

188 g of the precursor compound (A-1) and 16 g of 92% paraformaldehyde were put into a 1000 ml four-necked flask equipped with a cooling tube, and then dissolved in 500 ml of acetic acid. After adding 10 ml of sulfuric acid while cooling in an ice bath, it was heated to 80 degreeC in an oil bath, and it was made to react, stirring for 4 hours. After completion of the reaction, water was added to the resulting solution to reprecipitate the crude product. The crude product was redissolved in acetone and further reprecipitated with water, and then the precipitate was separated by filtration and vacuum dried to obtain 182 g of novolak-type phenolic resin (C-1) as an orange powder. The number average molecular weight (Mn) of the obtained novolak-type phenol resin (C-1) was 3946, the weight average molecular weight (Mw) was 8504, and the polydispersity (Mw/Mn) was 2.16. The GPC chart of the novolac-type phenolic resin (C-1) is shown in FIG. 5 .

Production Example 2 Synthesis of carboxylic acid-containing novolak-type phenolic resin

Instead of the precursor compound (A-1), 9.4 g (0.025 mol) of the precursor compound (A-1) and 8.7 g (0.025 mol) of the precursor compound (A'-2) were used in the same manner as in Production Example 1, 16.8 g of a novolac-type phenolic resin (C-2) was obtained as a red powder. The number average molecular weight (Mn) of the obtained novolak-type phenol resin (C-2) was 3331, the weight average molecular weight (Mw) was 6738, and the polydispersity (Mw/Mn) was 2.02. The GPC chart of the novolac-type phenolic resin (C-2) is shown in FIG. 6 .

Preparation Example 3 Synthesis of novolac resin

In a 2L four-necked flask equipped with a stirrer and a thermometer, 552 g (4 mol) of 2-hydroxybenzoic acid, 498 g (3 mol) of 1,4-bis (methoxymethyl) benzene, 2.5 g of p-toluenesulfonic acid, and 500 g of toluene were mixed. After introducing, the temperature was raised to 120°C, and a demethanol reaction was performed. The temperature was raised and distilled under reduced pressure, followed by distillation at 230°C for 6 hours under reduced pressure to obtain 882 g of pale yellow solid novolak resin (C'-3). The number average molecular weight (Mn) of the novolac resin (C'-3) was 1016, the weight average molecular weight (Mw) was 2782, and the polydispersity (Mw/Mn) was 2.74. The GPC chart of novolak resin (C'-3) is shown in FIG.

Preparation Example 4 Synthesis of novolak resin

648g (6mol) of m-cresol, 432g (4mol) of p-cresol, 2.5g (0.2mol) of oxalic acid, and 492g of 42% formaldehyde were added to a 2L four-necked flask equipped with a stirrer and a thermometer, and the temperature was raised to 100°C. , reacted. Dehydration and distillation were carried out at normal pressure to 200°C, followed by vacuum distillation at 230°C for 6 hours to obtain 736 g of pale yellow solid novolac resin (C'-4).

The number average molecular weight (Mn) of GPC of the novolac resin (C'-4) was 1450, the weight average molecular weight (Mw) was 10316, and the polydispersity (Mw/Mn) was 7.116. The GPC chart of novolak resin (C'-4) is shown in FIG.

Example 1

[Preparation of resin solution]

The novolak-type phenolic resin (C-1) prepared in Production Example 1 and propylene glycol monomethyl ether acetate (PGMEA) were mixed at a mass ratio of novolak-type phenolic resin (C-1):PGMEA = 20:80, A PGMEA solution of a rockfish-type phenolic resin (C-1) was obtained, and this solution was microfiltered with a 0.1 μm polytetrafluoroethylene disc filter to prepare a resin solution.

[composite evaluation]

5 g of the resin solution obtained in a 30 ml heat-resistant tube and metal nitrate hydrates Ca(NO ₃ ) ₂ 4H ₂ O, Zn(NO ₃ ) ₂ 6H ₂ O, Cu(NO ₃ ) ₂ 3H ₂ O and Fe(NO ₃ ) 0.2 g of 3.9H ₂ O was added _and heated to 100°C while shaking. The state of the mixture of the resin solution and the metal nitrate hydrate after heating was evaluated according to the following criteria. The results of gelation evaluation are shown in Table 1.

○: Immobile gelation

△: viscous liquid

×: no change in viscosity

Since non-freezing gelation or viscous liquidation was confirmed by the above evaluation, shaking treatment was performed at room temperature for 3 hours after further adding 1 g of aqueous hydrochloric acid solution. The state of the metal nitrate hydrate-containing resin solution after the shaking treatment was evaluated according to the following criteria, and the presence or absence of formation of a metal salt structure was confirmed. Table 1 shows the results of the solubilization evaluation.

○: low viscosity liquid

△: viscous liquid

×: no state change

From the results of Table 1, the novolak-type phenolic resin (C-1) of Production Example 1, which was made into a non-freezing gel or viscous liquid by adding a metal nitrate hydrate and liquefied with a low viscosity by further adding an aqueous hydrochloric acid solution, was added with a metal nitrate hydrate. As a result, it was confirmed that a metal salt structure was formed.

Formation of a cross-linked structure by the coordination bond between metal and novolac and decomposition of the cross-linked structure due to its dissociation are reversible when a metal nitrate hydrate is added to form a non-freeze gel or a viscous liquid, and an aqueous hydrochloric acid solution is further added to form a low-viscosity liquid. Since it is a behavior showing that it is, it shows that a metal salt of carboxylic acid is formed.

About the prepared resin solution, the following evaluation was performed separately. The results are shown in Table 1.

[Evaluation of alkali developability]

The obtained resin solution was applied on a 5-inch silicon wafer by a spin coater to a thickness of about 1 μm, and dried on a hot plate at 110° C. for 60 seconds to form a resin film on the silicon wafer. The obtained wafer was immersed in a developing solution (2.38% tetramethylammonium hydroxide aqueous solution) for 60 seconds and then dried on a hot plate at 110°C for 60 seconds. The film thickness before and after immersion in the developer was measured, and the value obtained by dividing the difference by 60 was determined as alkali developability (ADR1 (Å/s)).

To the obtained resin solution, photosensitizer P-200 (manufactured by Toyo Kosei Kogyo Co., Ltd.; 4,4'-[1-[4 -Condensate of 1 mole of [1-(4-hydroxyphenyl)-1methylethyl]phenyl]ethylidene]bisphenol and 2 moles of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride ) was added, and the resin composition was applied on a 5-inch silicon wafer to a thickness of about 1 μm by a spin coater, and dried on a hot plate at 110° C. for 60 seconds to form a resin film on the silicon wafer. The obtained wafer was immersed in a developing solution (2.38% tetramethylammonium hydroxide aqueous solution) for 60 seconds and then dried on a hot plate at 110°C for 60 seconds. The film thickness before and after immersion in the developer was measured, and the value obtained by dividing the difference by 60 was determined as alkali developability (ADR2 (Å/s)).

[Evaluation of heat resistance]

The obtained resin solution was applied on a 5-inch silicon wafer by a spin coater to a thickness of about 1 μm, and dried on a hot plate at 110° C. for 60 seconds to form a resin film on the silicon wafer. This resin film was scraped off, and the glass transition point temperature (hereinafter abbreviated as "Tg") was measured and evaluated according to the following criteria.

○: Tg is 150°C or higher

×: Tg is 150°C or less

In addition, the measurement of Tg was carried out using a differential thermal scanning calorimeter ("differential thermal scanning calorimeter (DSC) Q100" manufactured by TA Instruments Co., Ltd.) under a nitrogen atmosphere, in a temperature range of -100 to 200°C and a temperature increase rate of 10°C. /min was performed.

Example 2 and Comparative Example 1-2

A resin solution was prepared and evaluated in the same manner as in Example 1, except that the resin shown in Table 1 was used instead of the novolak-type phenol resin (C-1). The results are shown in Table 1. In addition, for the resin solutions of novolak resin (C'-3) and novolac resin (C'-4), when there was no change in viscosity in gelation evaluation, solization was not evaluated.

[Table 1]

Claims (9)

A resist composition comprising a metal salt of a novolac-type phenolic resin (C) containing an aromatic compound (A) represented by the following formula (1) and an aliphatic aldehyde (B) as essential reaction raw materials.

(In the formula (1), R ₁ and R ₂ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 9 carbon atoms, an alkoxy group, an aryl group, an aralkyl group, or a halogen atom.
m and n each independently represents an integer of 0 to 4.
When there are a plurality of R ₁ 's, the plurality of R ₁ 's may be the same as or different from each other.
When there are a plurality of R ₂ , the plurality of R ₂ may be the same or different.
R ₃ represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 9 carbon atoms, or a structural site having at least one substituent selected from an alkoxy group, a halogen group and a hydroxyl group on the hydrocarbon group) According to claim 1,
The resist composition wherein the metal salt is a metal carboxylic acid salt. According to claim 1 or 2,
A resist composition wherein the metal valency of the metal salt is at least one selected from calcium atoms, zinc atoms, copper atoms, and iron atoms. According to claim 1 or 2,
The resist composition wherein the aromatic compound (A) is a polycondensate of a phenolic compound, an aromatic aldehyde having a carboxyl group or a carboxyester group, and/or an aromatic ketone having a carboxy group or carboxyester group. According to claim 4,
The resist composition according to claim 1 , wherein the aromatic aldehyde having a carboxyl group is formylbenzoic acid. According to claim 1 or 2,
The resist composition, wherein the aliphatic aldehyde (B) is formaldehyde and/or paraformaldehyde. forming a resist film using the resist composition according to claim 1 or 2;
a step of exposing the resist film;
A pattern formation method including a step of forming a pattern by developing the exposed resist film using a developing solution. According to claim 7,
The pattern formation method in which the said exposure is exposure with an electron beam or extreme ultraviolet. A method for manufacturing an electronic device comprising the pattern formation method according to claim 7 .

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