TWI825250B - Resistor composition, pattern forming method and manufacturing method of electronic device - Google Patents

Abstract

An object of the present invention is to provide a resist composition that has high heat resistance and can be used in lithography using electron beams and extreme ultraviolet rays. Specifically, a resist composition containing a novolac-type phenol resin (C) using an aromatic compound (A) represented by the following formula (1) and an aliphatic aldehyde (B) as necessary reaction raw materials is used. metal salts;

(In the aforementioned formula (1), R ₁ and R ₂ each independently represent a hydrogen atom, an aliphatic hydrocarbon group with 1 to 9 carbon atoms, an alkoxy group, an aryl group, an aralkyl group or a halogen atom; m and n each independently represent means an integer from 0 to 4; when R ₁ is a plural number, the plural R _1s can be the same or different from each other; when R ₂ is a complex number, the plural R _2s can be the same or different from each other; R ₃ represents hydrogen atom, an aliphatic hydrocarbon group with 1 to 9 carbon atoms, or a structural portion having one or more substituents selected from an alkoxy group, a halo group, and a hydroxyl group on a hydrocarbon group).

Description

Resistor composition, pattern forming method and manufacturing method of electronic device

The present invention relates to resist compositions.

As resists used in the production of semiconductors such as ICs and LSIs, the production of display devices such as LCDs, and the production of printing original plates, it is known that photosensitizers using alkali-soluble resins, 1,2-naphthoquinonediazide compounds, etc. type photoresist. As the alkali-soluble resin, a positive photoresist composition using a mixture of m-cresol novolak resin and p-cresol novolak resin as the alkali-soluble resin has been proposed (for example, see Patent Document 1).

The positive photoresist composition described in Patent Document 1 was developed for the purpose of improving developability such as sensitivity. However, in recent years, semiconductors have become more highly integrated, and patterns tend to become thinner, requiring further excellence. sensitivity. However, in the positive photoresist composition described in Patent Document 1, there is a problem that sufficient sensitivity corresponding to thinning of lines cannot be obtained. Furthermore, since various heat treatments are performed in the manufacturing process of semiconductors and the like, high heat resistance is also required. However, the positive photoresist composition described in Patent Document 1 has a problem that it does not have sufficient heat resistance. .

In addition, especially at semiconductor manufacturing sites such as IC and LSI, which require more fine processing, lithography using electron beams or extreme ultraviolet (EUV) is being reviewed. As the wavelength of the exposure source becomes shorter, further improvement in characteristics of the resist composition corresponding to the wavelength is required.

[Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 2-55359

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

The present inventors conducted intensive examinations in order to solve the above-mentioned problems, and as a result discovered a resist composition containing a phenol obtained by reacting a carboxylic acid-containing phenolic trinuclear compound having a specific structure and an aliphatic aldehyde. The metal salt structure of the varnish-type phenol resin has high heat resistance and can be used in lithography using electron beams and extreme ultraviolet rays to complete the present invention.

That is, the present invention relates to a resist composition containing a novolac-type phenol resin (C) using an aromatic compound (A) represented by the following formula (1) and an aliphatic aldehyde (B) as necessary reaction raw materials. Metal salts.

(In the aforementioned formula (1), R ₁ and R ₂ each independently represent a hydrogen atom, an aliphatic hydrocarbon group with 1 to 9 carbon atoms, an alkoxy group, an aryl group, an aralkyl group or a halogen atom; m and n each independently represent represents an integer from 0 to 4; when R ₁ is a plural number, the plural R _1s may be the same or different from each other; when R ₂ is a complex number, the plural R _2s may be the same or different from each other; R ₃ represents hydrogen atom, an aliphatic hydrocarbon group with 1 to 9 carbon atoms, or a structural portion having one or more substituents selected from an alkoxy group, a halo group, and a hydroxyl group on a hydrocarbon group).

According to the present invention, a resist composition can be provided that has high heat resistance and can be used in lithography using electron beams and extreme ultraviolet rays.

[Form used to implement the invention]

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 changes within the scope that does not impair the effects of the present invention.

[Resistant composition]

The resist composition of the present invention contains an aromatic compound represented by the following formula (1) (A) A metal salt of a novolac-type phenol resin (C) that is a necessary reaction raw material with an aliphatic aldehyde (B).

(In the aforementioned formula (1), R ₁ and R ₂ each independently represent a hydrogen atom, an aliphatic hydrocarbon group with 1 to 9 carbon atoms, an alkoxy group, an aryl group, an aralkyl group or a halogen atom; m and n each independently represent means an integer from 0 to 4; when R ₁ is a plural number, the plural R _1s can be the same or different from each other; when R ₂ is a complex number, the plural R _2s can be the same or different from each other; R ₃ represents hydrogen atom, an aliphatic hydrocarbon group with 1 to 9 carbon atoms, or a structural portion having one or more substituents selected from an alkoxy group, a halo group, and a hydroxyl group on a hydrocarbon group).

The resist composition usually contains a resin that is decomposed by the action of an acid and changes in polarity (acid-decomposable resin) and a compound that generates acid upon irradiation with light (photoacid generator). In such a resist composition, the photoacid generator generates acid by exposure, and the polarity of the resin changes due to the action of the generated acid, thereby forming a desired pattern. However, due to a mechanism that easily causes uneven diffusion of acid, the resolution of the formed pattern may become insufficient.

In the resist composition of the present invention, the metal salt structure is decomposed due to exposure, metal ions are detached, and the polarity of the novolac-type phenol resin (C) is changed to form a desired pattern. In the resist composition of the present invention that is not accompanied by a mechanism that easily causes uneven acid diffusion, high resolution can be obtained. Especially in exposure using short-wavelength light such as electron beams and extreme ultraviolet rays, resolution or unevenness in pattern shape may easily become a problem, but the resist composition of the present invention can eliminate this problem.

As for the metal salt of the novolak-type phenol resin (C), some or all of the functional groups of the novolac-type phenol resin (C) may be converted into a metal salt structure. The metal salt of the novolak-type phenol resin (C) is preferably a carboxylic acid metal salt of the novolac-type phenol resin (C). The carboxylic acid metal salt of the novolac-type phenol resin (C) preferably has a structure represented by the following formula (X).

(In the aforementioned formula (X), R ₁ , R ₂ , R ₃ , m and n are the same as R ₁ , R ₂ , R ₃ , m and n of the aforementioned formula (1); * is the same as the aforementioned formula (1) The bonding point of any one of the three aromatic rings, the two * can be bonded to the same aromatic ring, or each can be bonded to a different aromatic ring; Met represents a metal atom; n represents an integer above 1).

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

In the resist composition of the present invention, it is sufficient that the novolac-type phenol resin (C) contains a metal salt structure, and the content of the metal salt structure is in all repeating units of the novolak-type phenol resin (C). , for example, 1 to 80 mol%, preferably 10 to 65 mol%, more preferably 20 to 50 mol%.

Whether or not the metal salt structure of the novolac-type phenol resin (C) is formed in the resist composition of the present invention can be confirmed by the method described in the Examples.

The components contained in the resist composition of the present invention will be described below. [Novolak type phenol resin] The novolac type phenol resin (C) is a resin which uses the aromatic compound (A) represented by the following formula (1) and the aliphatic aldehyde (B) as necessary reaction raw materials.

(In the aforementioned formula (1), R ₁ and R ₂ each independently represent a hydrogen atom, an aliphatic hydrocarbon group with 1 to 9 carbon atoms, an alkoxy group, an aryl group, an aralkyl group or a halogen atom; m and n each independently represent represents an integer from 0 to 4; when R ₁ is a plural number, the plural R _1s may be the same or different from each other; when R ₂ is a plural number, the plural R _2s may be the same or different from each other; R ₃ represents hydrogen atom, an aliphatic hydrocarbon group having 1 to 9 carbon atoms, or a structural moiety having one or more substituents selected from an alkoxy group, a halo group, and a hydroxyl group on a hydrocarbon group).

In the aforementioned formula (1), examples of the aliphatic hydrocarbon group having 1 to 9 carbon atoms in R ₁ , R ₂ and R ₃ include methyl, ethyl, propyl, isopropyl, butyl, and tert-butyl. alkyl groups with 1 to 9 carbon atoms and cycloalkyl groups with 3 to 9 carbon atoms, etc.

In the aforementioned formula (1), examples of the alkoxy groups of R ₁ and R ₂ include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, cyclohexyloxy, etc. .

In the aforementioned formula (1), examples of the aryl groups of R ₁ and R ₂ include phenyl, tolyl, xylyl, naphthyl, anthracenyl, and the like.

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

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

In the above formula (1), as "a structural moiety having one or more substituents selected from an alkoxy group, a halo group, and a hydroxyl group on a hydrocarbon group" of R ₃ , a halogenated alkyl group, a halogenated aryl group, 2 - Alkoxyalkoxy groups such as methoxyethoxy, 2-ethoxyethoxy, etc., alkyl alkoxy groups substituted by hydroxyl groups, etc.

In the aforementioned formula (1), each of n and m is preferably an integer of 2 or 3. When n and m are each 2, two R ₁ and two R ₂ are each independently preferably an alkyl group having 1 to 3 carbon atoms. At this time, each of the two R ₁ and the two R ₂ is preferably bonded to the 2, 5-position of the phenolic hydroxyl group.

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

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 carboxyl 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 an alkyl-substituted phenol. Examples of the alkyl group include an alkyl group having 1 to 8 carbon atoms, and preferably a methyl group.

Specific examples of the alkyl-substituted phenol (a1) include o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, p-octylphenol, and p-tertiary phenol. Butylphenol, o-cyclohexylphenol, m-cyclohexylphenol, p-cyclohexylphenol and other monoalkylphenols; 2,5-xylenol, 3,5-xylenol, 3,4-xylenol, 2 , dialkylphenols such as 4-xylenol and 2,6-xylenol; trialkylphenols such as 2,3,5-trimethylphenol and 2,3,6-trimethylphenol. Among these, dialkylphenol is preferred, and 2,5-xylenol and 2,6-xylenol are more preferred. The alkyl-substituted phenol (a1) system may be used individually by 1 type, or may use 2 or more types together.

Examples of the aromatic aldehyde (a2) having a carboxyl group include compounds having a formyl group on the aromatic core of benzene, naphthalene, phenol, resorcinol, naphthol, dihydroxynaphthalene, etc., in addition to the formyl group, Compounds having alkyl groups, alkoxy groups, halogen atoms, etc.

Specific examples of the aromatic aldehyde (a2) having a carboxyl group include 4-formylbenzoic acid, 2-formylbenzoic acid, 3-formylbenzoic acid, and methyl 4-formylbenzoate. , 4-formylbenzoic acid ethyl ester, 4-formylformyl benzoic acid propyl ester, 4-formylformyl benzoic acid isopropyl ester, 4-formylformyl benzoic acid butyl ester, 4-formylformyl benzoic acid isopropyl ester Butyl ester, tert-butyl 4-formyl benzoate, cyclohexyl 4-formyl benzoate, tert-octyl 4-formyl benzoate, etc. Among these, 4-formylbenzoic acid is preferred. The aromatic aldehyde (a2) having a carboxyl group may be used alone, or two or more types may be used in combination.

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

Specific examples of the aromatic ketone (a3) having a carboxyl group include 2-acetylbenzoic acid, 3-acetylbenzoic acid, 4-acetylbenzoic acid, and 2-acetylbenzoic acid. Methyl ester, ethyl 2-acetyl benzoate, propyl 2-acetyl benzoate, isopropyl 2-acetyl benzoate, butyl 2-acetyl benzoate, 2-acetyl benzoate Isobutyl formate, tert-butyl 2-acetyl benzoate, cyclohexyl 2-acetyl benzoate, tert-octyl 2-acetyl benzoate, etc. Among these, 2-acetylbenzoic acid and 4-acetylbenzoic acid are preferred. The aromatic ketone (a3) system may be used individually by 1 type, or may use 2 or more types together.

Specific examples of the aliphatic aldehyde (B) include formaldehyde, paraformaldehyde, 1,3,5-tris alkane, acetaldehyde, propionaldehyde, tetraformaldehyde, polyformaldehyde, trichloroacetaldehyde, hexamethylenetetramine, furfural, glyoxal, n-butyraldehyde, hexanal, allyl aldehyde, crotonaldehyde, acrolein, etc. The aliphatic aldehyde compound (B) may be used individually by 1 type, or may use 2 or more types together.

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

The method for producing the novolac-type phenol resin (C) preferably includes the following three steps 1 to 3. (step 1) An aromatic compound is obtained by polycondensation of an alkyl-substituted phenol (a1) and an aromatic aldehyde (a2) having a carboxyl group in the presence of an acid catalyst, using a solvent if necessary, and heating in the range of 60 to 140°C. (A). (step 2) The aromatic compound (A) obtained in step 1 is isolated from the reaction solution. (step 3) The aromatic compound (A) and the aliphatic aldehyde (B) isolated in step 2 are heated in the range of 60 to 140°C in the presence of an acid catalyst, using a solvent if necessary, to obtain phenol formaldehyde through polycondensation. Varnish type phenol resin (C).

Examples of the acid catalyst used in the above steps 1 and 3 include acetic acid, oxalic acid, sulfuric acid, hydrochloric acid, phenolsulfonic acid, p-toluenesulfonic acid, zinc acetate, manganese acetate, and the like. Only one type of these acid catalysts may be used, or two or more types may be used in combination. Moreover, among these acid catalysts, from the viewpoint of excellent activity, sulfuric acid and p-toluenesulfonic acid are preferred in step 1, and sulfuric acid, oxalic acid, and zinc acetate are preferred in step 3. In addition, the acid catalyst system may be added before the reaction or during the reaction.

Examples of solvents used optionally in the above steps 1 and 3 include monohydric alcohols such as methanol, ethanol, and propanol; ethylene glycol, 1,2-propanediol, 1,3-propanediol, and 1,4-butanediol. Alcohol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, trimethylene glycol, diethyl Polyols such as glycol, polyethylene glycol, and glycerol; 2-ethoxyethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol Glycol ethers such as monobutyl ether, ethylene glycol monoamyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl methyl ether, ethylene glycol monophenyl ether, etc.; 1,3-diol Alkane, 1,4-bis cyclic ethers such as alkanes; glycol esters such as ethylene glycol acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.; aromatic hydrocarbons such as toluene, xylene, etc. Only one type of these solvents may be used, or two or more types may be used in combination. Moreover, among these solvents, 2-ethoxyethanol is preferred because the solubility of the obtained compound is excellent.

The addition ratio of alkyl-substituted phenol (a1) and carboxyl-containing aromatic aldehyde (a2) in step 1 [(a1)/(a2)] depends on the removal and production of unreacted alkyl-substituted phenol (a1). In view of excellent product yield and purity of the reaction product, 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 of the aromatic compound (A) and the aliphatic aldehyde (B) in step 3 [(A)/(B)] can suppress excessive polymerization (gelation) and obtain a phenol resin for a resistor In terms of the appropriate molecular weight, 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 put into a poor solvent (S1) in which the reaction product is insoluble or poorly soluble, and the resulting precipitate is separated by filtration. Thereafter, the reaction product is dissolved in a solvent (S2) that is also mixed with the poor solvent (S1), and is again put into the poor solvent (S1), and the resulting precipitate is separated by filtration.

Examples of the poor solvent (S1) used at this time include water; monohydric alcohols such as methanol, ethanol, and propanol; aliphatic hydrocarbons such as n-hexane, n-heptane, n-octane, and cyclohexane; and toluene. , xylene and other aromatic hydrocarbons. Among these poor solvents (S1), water and methanol are preferred from the viewpoint of simultaneously removing the acid catalyst with high efficiency. On the other hand, examples of the solvent (S2) include monohydric alcohols 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, 1,9-nonanediol, trimethylene glycol, diethylene glycol , polyethylene glycol, glycerin and other polyols; 2-ethoxyethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether Glycol ethers such as ethylene glycol monoamyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl methyl ether, ethylene glycol monophenyl ether, etc.; 1,3-diol Alkane, 1,4-bis cyclic ethers such as alkanes; glycol esters such as ethylene glycol acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, etc. Moreover, when using water as the said poor solvent (S1), it is preferable that said (S2) is acetone. In addition, only one type of each of the aforementioned poor solvent (S1) and solvent (S2) may be used, or two or more types may be used in combination.

When aromatic hydrocarbons such as toluene and xylene are used as solvents in the above steps 1 and 3, if the temperature is heated above 80°C, the aromatic compound (A) generated by the reaction will be dissolved in the solvent. Direct cooling causes the aromatic compound (A) to crystallize, and the aromatic compound (A) can be separated by filtration. In this case, the aforementioned poor solvent (S1) and solvent (S2) may not be used.

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

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

(GPC measurement conditions) Measuring device: "HLC-8220 GPC" manufactured by Tosoh Corporation Pipe string: "Shodex KF802" made by Showa Denko Co., Ltd. (8.0mmФ×300mm) + "Shodex KF802" made by Showa Denko Co., Ltd. (8.0mmФ×300mm) + "Shodex KF803" made by Showa Denko Co., Ltd. (8.0mmФ×300mm) + "Shodex KF804" made by Showa Denko Co., Ltd. (8.0mmФ×300mm) Tube string temperature: 40℃ Detector: RI (differential refractometer) Data processing: "GPC-8020 model II version 4.30" manufactured by Tosoh Co., Ltd. Development solvent: tetrahydrofuran Flow rate: 1.0mL/min Sample: A tetrahydrofuran solution (100 μl) in which the resin solid content was filtered with a microfilter and converted to 0.5% by mass. Standard sample: the following monodisperse polystyrene

(Standard sample: monodisperse polystyrene) Tosoh Co., Ltd. "A-500" Tosoh Co., Ltd. "A-2500" Tosoh Co., Ltd. "A-5000" Tosoh Co., Ltd. "F-1" Tosoh Co., Ltd. "F-2" Tosoh Co., Ltd. "F-4" Tosoh Co., Ltd. "F-10" Tosoh Co., Ltd. "F-20"

[Metal atoms forming metal salts] Examples of metal atoms that form a metal salt with the novolac-type phenol resin (C) include calcium, zinc, copper, iron, aluminum, zirconium, hafnium, titanium, indium, tin, and the like. Among these, calcium, zinc, copper, iron, zirconium, hafnium and tin are preferred. The metal atom system mentioned above may be used individually by 1 type, or may be used in combination of 2 or more types.

The metal salt of the novolak-type phenol resin (C) can be obtained by adding metal salts such as hydrochloride, nitrate, sulfate, etc. of metal atoms and or formed from metal oxides. Among 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, relative to 100 parts by mass of the novolak-type phenol resin (C).

[Alkali-soluble resin] In the resist composition of the present invention, the novolak-type phenol resin (C) is an alkali-soluble resin, but it may also contain an alkali-soluble resin (D) other than the novolac-type phenol resin (C).

The alkali-soluble resin (D) may be any resin soluble in an alkali aqueous solution, and is preferably a cresol novolak resin. The aforementioned cresol novolak resin uses phenolic compounds and aldehyde compounds as reaction raw materials, and the novolak type phenol resin formed by condensation is preferably selected from o-cresol, m-cresol and p-cresol. A resin in which one or more phenolic compounds of the group are necessary reaction raw materials.

As the phenolic compound used as a reaction raw material of the cresol novolac resin, 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, and 3,4-xylenol. -Xylenols such as xylenol and 3,5-xylenol; ethylphenols such as o-ethylphenol, m-ethylphenol and p-ethylphenol; isopropylphenol, butylphenol, p-tertiary phenol Butylphenols such as butylphenol; alkylphenols such as p-amylphenol, p-octylphenol, p-nonylphenol, p-cumylphenol, etc.; Halogenation of fluorophenols, chlorophenols, bromophenols, iodophenols, etc. Phenol; 1-substituted phenols such as phenylphenol, aminophenol, nitrophenol, dinitrophenol, trinitrophenol, etc.; condensed polycyclic phenols such as 1-naphthol, 2-naphthol, etc.; resorcinol Phenol, alkylresorcinol, gallicol, catechol, alkylcatechol, hydroquinone, alkylhydroquinone, phloroglucinol, bisphenol A, bisphenol F, bisphenol S, dihydroxynaphthalene Polyphenols, etc. The phenolic compounds other than the aforementioned cresol may be used alone, or two or more types may be used in combination.

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

Examples of the aldehyde compound used as a raw material of the cresol novolac resin include formaldehyde, paraformaldehyde, and triacetal. Alkane, acetaldehyde, propionaldehyde, polyformaldehyde, trichloroacetaldehyde, hexamethylenetetramine, furfural, glyoxal, n-butyraldehyde, hexanal, allyl aldehyde, benzaldehyde, crotonaldehyde, acrolein, tetrahydrofuran Formaldehyde, phenyl acetaldehyde, o-toluene formaldehyde, salicylaldehyde, etc. Among these, formaldehyde is preferred. The aforementioned aldehyde compounds may be used alone or in combination of two or more types.

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

The condensation reaction of the aforementioned phenolic compound and 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, manganese acetate, and the like. Among these, oxalic acid is preferred because of its excellent catalytic activity. The acid catalyst system mentioned above may be used individually by 1 type, or may be used in combination of 2 or more types. The acid catalyst can be added before the reaction or during the reaction, either way is acceptable.

The addition ratio (molar ratio) of the phenolic compound and the aldehyde compound when preparing the cresol novolak resin is preferably in the range of 0.3 to 1.6, and more preferably in the range of 0.5 to 1.3. .

As a specific example of the reaction between the phenolic compound and the aldehyde compound when preparing the cresol novolak resin, the phenolic compound and the aldehyde compound are heated to 60 to 140° C. in the presence of an acid catalyst to proceed with the polycondensation reaction. , and then perform dehydration and monomer removal under reduced pressure conditions.

The resist composition of the present invention may or may not contain the photosensitizer (E). As the photosensitizer (E), a compound having a quinonediazide group can be used. Examples of the compound having a quinonediazide group include 2,3,4-trihydroxydiphenylketone, 2,4,4'-trihydroxydiphenylketone, and 2,4,6-trihydroxydiphenylketone. Diphenyl ketone, 2,3,6-trihydroxydiphenyl ketone, 2,3,4-trihydroxy-2'-methyldiphenyl ketone, 2,3,4,4'-tetrahydroxydiphenyl ketone base ketone, 2,2',4,4'-tetrahydroxydiphenyl ketone, 2,3',4,4',6-pentahydroxydiphenyl ketone, 2,2',3,4,4' -Pentahydroxydiphenylketone, 2,2',3,4,5-pentahydroxydiphenylketone, 2,3',4,4',5',6-hexahydroxydiphenylketone, 2, Polyhydroxydiphenylketone compounds such as 3,3',4,4',5'-hexahydroxydiphenylketone; 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]ethylene}bisphenol, 3,3'-dimethyl-{1-[4-[2-(3 Bis[(poly)hydroxyphenyl]alkyl compounds such as -methyl-4-hydroxyphenyl)-2-propyl]phenyl]ethylene}bisphenol; see (4-hydroxyphenyl)methane, Bis(4-hydroxy-3,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-4-hydroxyphenylmethane, bis( 4-hydroxy-3,5-dimethylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-2-hydroxyphenylmethane, bis(4- Hydroxy-2,5-dimethylphenyl)-3,4-dihydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-3,4-dihydroxyphenylmethane, etc. (Hydroxyphenyl)methanes or their methyl substitutes; 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-hydroxy Phenylmethane, bis(5-cyclohexyl-4-hydroxy-3-methylphenyl)-3-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-3-methylphenyl)-2 -Hydroxyphenylmethane, bis(3-cyclohexyl-2-hydroxyphenyl)-4-hydroxyphenylmethane, bis(3-cyclohexyl-2-hydroxyphenyl)-2-hydroxyphenylmethane, bis( 5-cyclohexyl-2-hydroxy-4-methylphenyl)-2-hydroxyphenylmethane, bis(5-cyclohexyl-2-hydroxy-4-methylphenyl)-4-hydroxyphenylmethane, etc. Bis(cyclohexylhydroxyphenyl)(hydroxyphenyl)methane or its methyl substitutes and naphthoquinone-1,2-diazide-5-sulfonic acid or naphthoquinone-1,2-diazide - Complete ester compounds, partial ester compounds, amide compounds or partial amide compounds of 4-sulfonic acid, o-anthraquinonediazide sulfonic acid, and other sulfonic acids having a quinonediazide group. Only one type of these photosensitive agents (E) may be used, or two or more types may be used in combination.

The content of the photosensitive agent (E) in the resist composition of the present invention, in order to obtain good sensitivity and obtain the desired pattern, is 100% relative to the total of the novolac-type phenolic resin (C) and the alkali-soluble resin (D). The mass part is preferably in the range of 3 to 50 mass parts, and more preferably in the range of 5 to 30 mass parts.

The resist composition of the present invention preferably contains 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, diethylene glycol dibutyl ether, etc.; Methyl glycol Ethylene glycol alkyl ether acetate such as luosu acetate, ethyl cellulosu acetate; propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate Acid esters such as propylene glycol alkyl ether acetate; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl amyl ketone, etc.; two cyclic ethers such as alkanes; methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethoxyethyl acetate, ethyl glycolate, 2- Hydroxy-3-methylbutyric acid methyl ester, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, ethyl formate, ethyl acetate, butyl acetate, Esters of methyl acetyl acetate, ethyl acetyl acetate, etc. Only one type of these solvents (F) may be used, or two or more types may be used in combination.

The content of the solvent (F) in the resist composition of the present invention is preferably The solid content concentration in the product is 15 to 65% by mass.

The resist composition of the present invention only needs to contain a metal salt of a novolac-type phenolic resin (C) and an optional alkali-soluble resin (D), a photosensitizer (E) and a solvent (F). It may also contain a novolac-type resist composition. Metal salt of phenolic resin (C) and optional alkali-soluble resin (D), photosensitive agent (E), solvent (F) and components other than components (C) to (F) (such as fillers, pigments, modifiers) (more than one selected from a surfactant, an adhesion enhancer, a dissolution accelerator such as a flattening agent), and unavoidable impurities may be included within a range that does not impair the effects of the present invention.

The resist composition of the present invention is, for example, 80 mass % or more, 90 mass % or more, 95 mass % or more, 98 mass % or more or 100 mass % of solid content other than the solvent (F), but may also contain novolac-type phenol. The metal salt of the resin (C) and optional components other than the alkali-soluble resin (D), photosensitive agent (E), and components (C) to (F).

The resist composition of the present invention can be stirred and mixed with novolak type phenolic resin (C), metal salts, optionally blended other alkali-soluble resins (D), photosensitive agents (E) and solvents (F) by ordinary methods. , and various additives are added as needed to prepare a uniform liquid.

When blending solids such as fillers and pigments into the resist composition of the present invention, it is preferred to use a dispersing device such as a dissolver, homogenizer, and three-roller mill for dispersion and mixing. In addition, in order to remove coarse particles or impurities, the composition may be filtered using a mesh filter, a membrane filter, or the like.

[Pattern forming method] The resist composition of the present invention can be used as a negative photoresist composition or as a positive photoresist. The method for producing a pattern using the resist composition of the present invention includes: forming a resist film using the resist composition of the present invention, exposing the resist film, and using a developer to convert the exposed The step of developing a resist film to form a pattern.

The formation of the resist film, the exposure of the resist film, and the development of the exposed resist film can be performed by well-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, electron beams, and the like. Among these light sources, ultraviolet light is preferred, and the g-line (wavelength 436nm), i-line (wavelength 365nm), and EUV laser (wavelength 13.5nm) of a high-pressure mercury lamp are suitable.

As the alkali developer used in development after exposure, for example, inorganic alkaline substances such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia water, etc.; ethylamine, n-propylamine, etc. can be used. Primary amines; secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcoholamines such as dimethylethanolamine and triethanolamine; hydroxide Quaternary ammonium salts of tetramethylammonium and tetraethylammonium hydroxide; alkaline aqueous solutions of cyclic amines such as pyrrole and piperidine. In these alkaline developing solutions, alcohol, surfactant, etc. may be appropriately added and used as needed. The alkali concentration of the alkali developer is generally preferably in the range of 2 to 5% by mass, and a 2.38% by mass tetramethylammonium hydroxide aqueous solution is generally used.

The pattern forming method of the present invention can be applied to the manufacturing process of electronic devices. Examples of the electronic device include household electrical equipment, office automation equipment, media-related equipment, optical equipment, communication equipment, and the like.

[Example]

Hereinafter, the present invention will be explained concretely through Examples and Comparative Examples.

Synthesis Example 1 Synthesis of Phenolic Trinuclear Compound Containing Carboxylic Acid

In a 2000ml 4-neck flask equipped with a cooling tube, add 293.2g (2.4mol) of 2,5-xylenol and 150g (1mol) of 4-formylbenzoic acid, and dissolve them in 500ml of acetic acid. After adding 5 ml of sulfuric acid while cooling in an ice bath, the mixture was heated to 100° C. with a heating pack and reacted while stirring for 2 hours. After the reaction is completed, water is added to the resulting solution to reprecipitate the crude product. The crude product was redissolved in acetone and reprecipitated with water. The precipitate was separated by filtration and vacuum dried to obtain 283 g of a precursor compound (A-1) in light peach color crystals.

The obtained precursor compound (A-1) was subjected to ¹³ C-NMR measurement and was confirmed to be a compound represented by the following structural formula. Moreover, the purity calculated from the GPC chart (GPC purity) was 95.3%. Figure 1 shows the GPC chart of the precursor compound (A-1), and Figure 2 shows the ¹³ C-NMR chart.

Synthesis Example 2 Synthesis of Phenolic Trinuclear Compounds In a 2000ml 4-neck flask equipped with a cooling tube, add 293.2g (2.4mol) of 2,5-xylenol and 122g (1mol) of 2-hydroxybenzaldehyde, and dissolve them in 500ml of 2-ethoxyethanol. middle. After adding 10 ml of sulfuric acid while cooling in an ice bath, the mixture was heated to 100° C. with a heating pack and reacted while stirring for 2 hours. After the reaction is completed, water is added to the resulting solution to reprecipitate the crude product. The crude product was redissolved in acetone and reprecipitated with water. The precipitate was separated by filtration and vacuum dried to obtain 283 g of a white crystal precursor compound (A'-2).

The obtained precursor compound (A'-2) was subjected to ¹³ C-NMR measurement and was confirmed to be a compound represented by the following structural formula. Moreover, the purity calculated from the GPC chart (GPC purity) was 98.2%. Figure 3 shows the GPC chart of the precursor compound (A'-2), and Figure 4 shows the ¹³ C-NMR chart.

Production Example 1 Synthesis of carboxylic acid-containing novolac-type phenol resin In a 1000 ml 4-neck flask equipped with a cooling tube, 188 g of the precursor compound (A-1) and 16 g of 92% paraformaldehyde were added, and then dissolved in 500 ml of acetic acid. After adding 10 ml of sulfuric acid while cooling in an ice bath, the mixture was heated to 80° C. in an oil bath and reacted while stirring for 4 hours. After the reaction is completed, water is added to the resulting solution to reprecipitate the crude product. The crude product was redissolved in acetone and reprecipitated with water. The precipitate was separated by filtration and vacuum dried to obtain 182 g of an orange powder novolac-type phenol resin (C-1). 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. Figure 5 shows the GPC chart of the novolak type phenol resin (C-1).

Production Example 2 Synthesis of carboxylic acid-containing novolac-type phenol resin The same procedure as Production Example 1 was used except that 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 instead of the precursor compound (A-1). Similarly, 16.8 g of novolac-type phenol resin (C-2) as a light red powder was obtained. 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. Figure 6 shows the GPC chart of the novolak type phenol resin (C-2).

Production Example 3 Synthesis of Novolak Resin In a 2L 4-neck flask equipped with a mixer and a thermometer, add 552g (4mol) of 2-hydroxybenzoic acid, 498g (3mol) of 1,4-bis(methoxymethyl)benzene, and 2.5g of p-toluenesulfon Acid and 500g of toluene were heated to 120°C to perform a demethanolization reaction. The temperature was raised and distilled under reduced pressure, and distillation under reduced pressure was carried out at 230°C for 6 hours to obtain 882 g of a light yellow solid novolac resin (C'-3). The novolak resin (C'-3) has a number average molecular weight (Mn) of 1016, a weight average molecular weight (Mw) of 2782, and a polydispersity (Mw/Mn) of 2.74. The GPC pattern of the novolac resin (C'-3) is shown in Figure 7 .

Production Example 4 Synthesis of Novolak Resin In a 2L 4-neck flask equipped with a mixer and a thermometer, add 648g (6mol) of m-cresol, 432g (4mol) of p-cresol, 2.5g (0.2mol) of oxalic acid, and 492g of 42% formaldehyde, and heat it to 100 ℃ to react. The mixture was dehydrated under normal pressure and distilled to 200°C, and then distilled under reduced pressure at 230°C for 6 hours to obtain 736 g of a light yellow solid novolac resin (C'-4). The GPC of the novolak resin (C'-4) is a number average molecular weight (Mn) of 1450, a weight average molecular weight (Mw) of 10316, and a polydispersity (Mw/Mn) of 7.116. The GPC pattern of the novolac resin (C'-4) is shown in Figure 8.

Example 1 [Preparation of resin solution] The novolak-type phenol resin (C-1) and propylene glycol monomethyl ether acetate (PGMEA) prepared in Production Example 1 were prepared in a mass ratio of novolak-type phenol resin (C-1):PGMEA=20:80. The mixture was mixed to obtain a PGMEA solution of the novolac-type phenol resin (C-1). This solution was precision filtered with a 0.1 μm polytetrafluoroethylene disc filter to prepare a resin solution.

[Composite evaluation] 5 g of the obtained resin solution and 0.2 g each of Ca(NO ₃ ) ₂・4H ₂ O and Zn(NO ₃ ) ₂・6H ₂ O as metal nitrate hydrates were added to a 30 ml heat-resistant tube. , Cu(NO ₃ ) ₂ ·3H ₂ O and Fe(NO ₃ ) ₃ ·9H ₂ O, and heated to 100°C while shaking. The state of the mixture of the heated resin solution and metal nitrate hydrate was evaluated based on the following criteria. Table 1 shows the results of gelation evaluation. ○: Does not gel and becomes △: becomes viscous and liquid ×: No change in viscosity

Based on the above evaluation, after confirming that it does not gel or become a viscous liquid, 1 g of aqueous hydrochloric acid solution is added, and the mixture is shaken at room temperature for 3 hours. The state of the resin solution containing the metal nitrate hydrate after the shaking treatment was evaluated according to the following criteria to confirm whether or not a metal salt structure was formed. Table 1 shows the results of the solization evaluation. ○：Low viscosity liquid △: viscous liquid ×: No status change

From the results in Table 1, it was confirmed that the novolak-type phenol resin (C-1) of Production Example 1 did not gel or become a viscous liquid due to the addition of metal nitrate hydrate, and was liquefied with a low viscosity due to the addition of a hydrochloric acid aqueous solution. ), a metal salt structure is formed by adding metal nitrate hydrate.

The reason why gelation or viscous liquidization does not occur due to the addition of metal nitrate hydrate, and the low-viscosity liquidization due to the addition of hydrochloric acid aqueous solution is due to the following behavior: coordination bonding between metal and novolak varnish The formation of the cross-linked structure and the decomposition of the cross-linked structure caused by its dissociation are reversible, so it means that a metal salt of carboxylic acid has been formed.

The prepared resin solution was separately evaluated as follows. The results are shown in Table 1. [Evaluation of alkali developability] The obtained resin solution was applied with a spin coater so that the thickness was about 1 μm on a 5-inch silicon wafer, 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 developer (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 difference was divided by 60 to determine the alkali developability (ADR1 (Å/s)).

To the obtained resin solution, the photosensitizer P-200 (manufactured by Toyo Gosei Kogyo Co., Ltd.; 1 mo 4,4'-[1-[4-[1-(4-hydroxyphenyl)-1methylethyl]phenyl]ethylene]bisphenol with 2 moles of 1,2-naphthoquinone -2-diazide-5-sulfonyl chloride condensate), use a spin coater to apply this resin composition to a thickness of about 1 μm on a 5-inch silicon wafer, and place it on a hot plate at 110°C. It is dried for 60 seconds to form a resin film on the silicon wafer. The obtained wafer was immersed in a developer (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 difference was divided by 60 to determine the alkali developability (ADR2 (Å/s)).

[Heat resistance evaluation] The obtained resin solution was applied with a spin coater so that the thickness was about 1 μm on a 5-inch silicon wafer, and dried on a hot plate at 110° C. for 60 seconds to form a resin film on the silicon wafer. The resin film was scraped off, the glass transition point temperature (hereinafter referred to as "Tg") was measured, and the evaluation was performed based on the following standards. ○: Tg is 150℃ or above ×: Tg is below 150°C In addition, Tg was measured using a differential scanning calorimeter ("Differential scanning calorimeter (DSC) Q100" manufactured by TA Instruments Co., Ltd.) in a nitrogen environment, with a temperature range of -100 to 200°C and a temperature rise rate of 10°C. / minute conditions.

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, regarding the resin solutions of novolak resin (C’-3) and novolac resin (C’-4), if there is no change in viscosity during gelation evaluation, the evaluation of solization will not be performed.

[Table 1] Example 1 Example 2 Comparative example 1 Comparative example 2 Resin C-1 C-2 C'-3 C'-4 Alkali developability ADR1 [Å/s] 15000 10000 3500 110 ADR2 [Å/s] 80 56 2900 15 heat resistance Tg [℃] 270 220 52 110 determination ○ ○ × × Compounding Ca(NO ₃ ) ₂ ･4H ₂ O gelation △ △ × × Solification ○ ○ - - Zn(NO ₃ ) ₂ ･6H ₂ O gelation △ △ × × Solification ○ ○ - - Cu(NO ₃ ) ₂ ･3H ₂ O gelation ○ ○ △ × Solification ○ ○ × - Fe(NO ₃ ) ₃ ･9H ₂ O gelation ○ ○ △ × Solification ○ ○ △ -

without.

Figure 1 is a GPC chart of the precursor compound obtained in Synthesis Example 1.

Figure 2 is a ¹³ C-NMR chart of the precursor compound obtained in Synthesis Example 1.

Figure 3 is a GPC chart of the precursor compound obtained in Synthesis Example 2.

Figure 4 is a ¹³ C-NMR chart of the precursor compound obtained in Synthesis Example 2.

Fig. 5 is a GPC chart of the novolac-type phenol resin obtained in Production Example 1.

Fig. 6 is a GPC chart of the novolac-type phenol resin obtained in Production Example 2.

Figure 7 is a GPC chart of the novolac resin obtained in Production Example 3.

Figure 8 is a GPC chart of the novolak resin obtained in Production Example 4.

without.

Claims (9)

A resist composition, which contains a metal salt of a novolac-type phenol resin (C) using an aromatic compound (A) represented by the following formula (1) and an aliphatic aldehyde (B) as necessary 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, or a halogen atom; m and n each independently represent a 0 to 4 Integer; when R ₁ is a complex number, the plural R _1s can be the same or different from each other; when R ₂ is a complex number, the plural R _2s can be the same or different from each other; R ₃ represents the number of hydrogen atoms and carbon atoms 1 ~9 aliphatic hydrocarbon group or a structural position with more than one substituent selected from alkoxy, halo and hydroxyl groups on the hydrocarbon group). The resist composition of claim 1, wherein the metal salt is a carboxylic acid metal salt. The resist composition of claim 1 or 2, wherein the metal atom of the metal salt is at least one selected from the group consisting of calcium atoms, zinc atoms, copper atoms and iron atoms. The resist composition of claim 1 or 2, wherein the aromatic compound (A) is a phenol compound and an aromatic aldehyde having a carboxyl or carboxyl ester group and/or Polycondensates of aromatic ketones with carboxyl or carboxyl ester groups. The resist composition of claim 4, wherein the aromatic aldehyde having a carboxyl group is formicyl benzoic acid. The resist composition of claim 1 or 2, wherein the aliphatic aldehyde (B) is formaldehyde and/or paraformaldehyde. A pattern forming method, which includes: the steps of using the resist composition of any one of claims 1 to 6 to form a resist film, the steps of exposing the resist film, and using a developer to expose the exposed resist film. The step of developing a resist film to form a pattern. The pattern forming method of claim 7, wherein the exposure is exposure by electron beam or extreme ultraviolet light. A method of manufacturing an electronic device, which includes the pattern forming method of claim 7 or 8.