WO2020137309A1 - Resist composition - Google Patents

Abstract

The purpose of the present invention is to provide a resist composition which exhibits high heat resistance and can be used in types of lithography that use electron beams and extreme ultraviolet radiation. Specifically, the present invention uses a resist composition that contains a metal salt of a novolac type phenolic resin (C), which is obtained using (A) an aromatic compound represented by formula (1) and (B) an aliphatic aldehyde as essential reaction raw materials. (In formula (1), R₁ and R₂ each independently denote a hydrogen atom, an aliphatic hydrocarbon group having 1-9 carbon atoms, an alkoxy group, an aryl group, an aralkyl group or a halogen atom. m and n each independently denote an integer between 0 and 4. In cases where a plurality of R₁ groups are present, the plurality of R₁ groups may be the same as, or different from, each other. In cases where a plurality of R₂ groups are present, the plurality of R₂ groups may be the same as, or different from, each other. R₃ denotes a hydrogen atom, an aliphatic hydrocarbon group having 1-9 carbon atoms, or a structural moiety having one or more substituent groups selected from among alkoxy groups, halogen groups and hydroxyl groups on a hydrocarbon group.)

Description

Resist composition

The present invention relates to a resist composition.

A positive photoresist using an alkali-soluble resin and a photosensitizer such as a 1,2-naphthoquinonediazide compound as a resist used in the production of semiconductors such as IC and LSI, the production of display devices such as LCD, and the production of printing original plates. It has been 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, for example, Patent Document 1).

The positive photoresist composition described in Patent Document 1 was developed for the purpose of improving developability such as sensitivity, but in recent years, the degree of integration of semiconductors has increased, and the pattern tends to be thin, Greater sensitivity is required. However, the positive photoresist composition described in Patent Document 1 has a problem that sufficient sensitivity for thinning cannot be obtained. Further, since various heat treatments are performed in the manufacturing process of semiconductors and the like, high heat resistance is also required, but the positive photoresist composition described in Patent Document 1 does not have sufficient heat resistance. There was a problem.

Furthermore, especially in the field of semiconductor manufacturing such as IC and LSI, finer processing is required, and lithography using electron beams or extreme ultraviolet rays (EUV) is being considered. With the shortening of the wavelength of the exposure source, there has been a demand for further improvement in the characteristics of the resist composition corresponding thereto.

JP-A-2-55359

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

MEANS TO SOLVE THE PROBLEM As a result of earnestly studying in order to solve the said subject, the metal of the novolak-type phenol resin obtained by making a carboxylic acid containing phenol trinuclear compound which has a specific structure react with an aliphatic aldehyde. The present invention has been completed by finding that a resist composition containing a salt structure has high heat resistance and can be used for lithography using electron beams and extreme ultraviolet rays.

That is, the present invention provides a resist composition containing a metal salt of a novolac type phenol resin (C), which contains an aromatic compound (A) represented by the following formula (1) and an aliphatic aldehyde (B) as essential reaction raw materials. It is about things.

（前記式（１）中、Ｒ_１及びＲ_２は、それぞれ独立に、水素原子、炭素原子数１～９の脂肪族炭化水素基、アルコキシ基、アリール基、アラルキル基又はハロゲン原子を表す。
　ｍ及びｎは、それぞれ独立に、０～４の整数を表す。
　Ｒ_１が複数ある場合、複数のＲ_１は互いに同じでも異なってもよい。
　Ｒ_２が複数ある場合、複数のＲ_２は互いに同じでも異なってもよい。
　Ｒ_３は、水素原子、炭素原子数１～９の脂肪族炭化水素基、又は炭化水素基上にアルコキシ基、ハロゲン基及び水酸基から選択される置換基を１以上有する構造部位を表す。）

(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 represent an integer of 0 to 4.
When R ₁ is a plurality, the plurality of R ₁ may be the same or different.
When R ₂ are a plurality, 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 moiety having at least one substituent selected from an alkoxy group, a halogen group and a hydroxyl group on the hydrocarbon group. )

The present invention can provide a resist composition which has high heat resistance and can be used for lithography using electron beams and extreme ultraviolet rays.

It is a GPC chart figure of the precursor compound obtained by the synthesis example 1. FIG. 3 is a ¹³ C-NMR chart diagram of the precursor compound obtained in Synthesis Example 1. It is a GPC chart figure of the precursor compound obtained by the synthesis example 2. FIG. 9 is a ¹³ C-NMR chart diagram of the precursor compound obtained in Synthesis Example 2. It is a GPC chart figure of the novolak-type phenol resin obtained in manufacture example 1. It is a GPC chart figure of the novolac-type phenol resin obtained in manufacture example 2. FIG. 6 is a GPC chart diagram of a novolac resin obtained in Production Example 3. It is a GPC chart figure of the novolak resin obtained in manufacture example 4.

An embodiment of the present invention will be described below. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within a range that does not impair the effects of the present invention.

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

（前記式（１）中、Ｒ_１及びＲ_２は、それぞれ独立に、水素原子、炭素原子数１～９の脂肪族炭化水素基、アルコキシ基、アリール基、アラルキル基又はハロゲン原子を表す。
　ｍ及びｎは、それぞれ独立に、０～４の整数を表す。
　Ｒ_１が複数ある場合、複数のＲ_１は互いに同じでも異なってもよい。
　Ｒ_２が複数ある場合、複数のＲ_２は互いに同じでも異なってもよい。
　Ｒ_３は、水素原子、炭素原子数１～９の脂肪族炭化水素基、又は炭化水素基上にアルコキシ基、ハロゲン基及び水酸基から選択される置換基を１以上有する構造部位を表す。）

(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 represent an integer of 0 to 4.
When R ₁ is a plurality, the plurality of R ₁ may be the same or different.
When R ₂ are a plurality, 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 moiety having at least one substituent selected from an alkoxy group, a halogen group and a hydroxyl group on the hydrocarbon group. )

The resist composition usually contains a resin that decomposes due to the action of an acid to change its polarity (acid-decomposable resin), and a compound that generates an acid when irradiated with light (a photo-acid generator). In such a resist composition, the photo-acid generator generates an acid upon exposure, and the action of the generated acid changes the polarity of the resin to form a desired pattern. However, the resolution of the formed pattern may be insufficient due to the mechanism of unevenness of acid diffusion.

In the resist composition of the present invention, a desired pattern is formed by the decomposition of the metal salt structure by the exposure to the desorption of metal ions and the change in polarity of the novolac type phenolic resin (C). With the resist composition of the present invention, which does not have the mechanism of unevenness of acid diffusion, a high resolution can be obtained. In particular, in exposure using light having a short wavelength such as an electron beam or extreme ultraviolet rays, the resolution and the unevenness of the pattern shape are likely to cause problems, but the resist composition of the present invention can solve this problem.

The metal salt of the novolac type phenol resin (C) may have a metal salt structure in part or all of the functional groups of the novolac type phenol resin (C).
The metal salt of the novolac 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).

（前記式（Ｘ）中、
　Ｒ_１、Ｒ_２、Ｒ_３、ｍ及びｎは、前記式（１）のＲ_１、Ｒ_２、Ｒ_３、ｍ及びｎと同じである。
　＊は、前記式（１）の３つの芳香環のいずれかとの結合点であり、２つの＊は同一の芳香環に結合してもよいし、それぞれ異なる芳香環に結合してもよい。
　Ｍｅｔは、金属原子を表す。
　ｎは１以上の整数を表す。）

(In the 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 point of attachment to any of the three aromatic rings of the above formula (1), and two * may be attached to the same aromatic ring or different aromatic rings.
Met represents a metal atom.
n represents an integer of 1 or more. )

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

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

Whether or not the metal salt structure of the novolak type phenolic resin (C) is formed in the resist composition of the present invention is confirmed by the method described in the examples.

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

（前記式（１）中、Ｒ_１及びＲ_２は、それぞれ独立に、水素原子、炭素原子数１～９の脂肪族炭化水素基、アルコキシ基、アリール基、アラルキル基又はハロゲン原子を表す。
　ｍ及びｎは、それぞれ独立に、０～４の整数を表す。
　Ｒ_１が複数ある場合、複数のＲ_１は互いに同じでも異なってもよい。
　Ｒ_２が複数ある場合、複数のＲ_２は互いに同じでも異なってもよい。
　Ｒ_３は、水素原子、炭素原子数１～９の脂肪族炭化水素基、又は炭化水素基上にアルコキシ基、ハロゲン基及び水酸基から選択される置換基を１以上有する構造部位を表す。）

(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 represent an integer of 0 to 4.
When R ₁ is a plurality, the plurality of R ₁ may be the same or different.
When R ₂ are a plurality, 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 moiety 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), the aliphatic hydrocarbon group having 1 to 9 carbon atoms represented by R ₁ , R ₂ and R ₃ is a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group or a t-butyl group. And hexyl group, cyclohexyl group, heptyl group, octyl group, nonyl group and the like, and alkyl groups having 1 to 9 carbon atoms and cycloalkyl groups having 3 to 9 carbon atoms.

In the formula (1), examples of the alkoxy group for R ₁ and R ₂ include a methoxy group, an ethoxy group, a propyloxy group, a butoxy group, a pentyloxy group, a hexyloxy group, and a cyclohexyloxy group.

In the formula (1), examples of the aryl group represented by 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 represented by 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 represented by R ₁ and R ₂ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

In the above formula (1), “a structural moiety having at least one substituent selected from an alkoxy group, a halogen group and a hydroxyl group on the hydrocarbon group” for R ₃ is a halogenated alkyl group, a halogenated aryl group, 2 Examples thereof include an alkoxyalkoxy group such as a -methoxyethoxy group and a 2-ethoxyethoxy group, and an alkylalkoxy group substituted with a hydroxy group.

In the above 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 two R ₁ and two R ₂ are each independently an alkyl group having 1 to 3 carbon atoms. At this time, two R ₁ and two R ₂ are preferably bonded to the 2,5-position of the phenolic hydroxyl group.

As the aromatic compound (A) represented by the formula (1), those having the same structure may be used alone, 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 of 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 of an alkyl-substituted phenol (a1) and an aromatic ketone (a3) having a carboxyl group.

The alkyl-substituted phenol (a1) is a phenol having an alkyl group substituted, 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, pt-butylphenol, o. -Monoalkylphenols such as cyclohexylphenol, m-cyclohexylphenol and p-cyclohexylphenol; dialkyl such as 2,5-xylenol, 3,5-xylenol, 3,4-xylenol, 2,4-xylenol and 2,6-xylenol Alkylphenol; trialkylphenols such as 2,3,5-trimethylphenol, 2,3,6-trimethylphenol and the like can be mentioned. Among these, dialkylphenol is preferable, and 2,5-xylenol and 2,6-xylenol are more preferable. The alkyl-substituted phenol (a1) may be used alone or in combination of two or more.

The aromatic aldehyde (a2) having a carboxyl group is a compound having a formyl group on the aromatic nucleus such as benzene, naphthalene, phenol, resorcin, naphthol, and dihydroxynaphthalene, and an alkyl group, an alkoxy group, a halogen atom in addition to the formyl group. And the like.

Specific examples of the aromatic aldehyde (a2) having a carboxyl group include 4-formylbenzoic acid, 2-formylbenzoic acid, 3-formylbenzoic acid, methyl 4-formylbenzoate, ethyl 4-formylbenzoate, 4- Propyl formyl benzoate, isopropyl 4-formyl benzoate, butyl 4-formyl benzoate, isobutyl 4-formyl benzoate, tertiary butyl 4-formyl benzoate, cyclohexyl 4-formyl benzoate, tertiary octyl benzoyl benzoate Etc. Of these, 4-formylbenzoic acid is preferable. The aromatic aldehyde (a2) having a carboxyl group may be used alone or in combination of two or more.

The aromatic ketone (a3) having a carboxyl group is a compound having at least one carboxyl group or its ester derivative and a carbonyl group in the 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 and ethyl 2-acetylbenzoate. , Propyl 2-acetylbenzoate, Isopropyl 2-acetylbenzoate, Butyl 2-acetylbenzoate, Isobutyl 2-acetylbenzoate, Tertiarybutyl 2-acetylbenzoate, Cyclohexyl 2-acetylbenzoate, 2-Acetylbenzoic acid Examples include tertiary octyl. Of these, 2-acetylbenzoic acid and 4-acetylbenzoic acid are preferable.
The aromatic ketone (a3) may be used alone 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-. Butyraldehyde, caproaldehyde, allyl aldehyde, crotonaldehyde, acrolein, etc. are mentioned. As the aliphatic aldehyde compound (B), one type may be used alone, or two or more types may be used in combination.

Formaldehyde is preferable as the aliphatic aldehyde (B).
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 used is in the range of 0.05 to 1 mol with respect to 1 mol of formaldehyde. It is preferable.

The method for producing the novolac type phenolic resin (C) preferably includes the following three steps 1 to 3.
(Process 1)
By subjecting the alkyl-substituted phenol (a1) and the aromatic aldehyde (a2) having a carboxyl group to the presence of an acid catalyst and optionally a solvent in the range of 60 to 140° C. for polycondensation, An aromatic compound (A) is obtained.
(Process 2)
The aromatic compound (A) obtained in step 1 is isolated from the reaction solution.
(Process 3)
Aromatic compound (A) and aliphatic aldehyde (B) isolated in step 2 are heated in the range of 60 to 140° C. in the presence of an acid catalyst and, if necessary, a solvent to be polycondensed. Thus, a novolac type phenol resin (C) is obtained.

Examples of the acid catalyst used in the above step 1 and step 3 include acetic acid, oxalic acid, sulfuric acid, hydrochloric acid, phenolsulfonic acid, paratoluenesulfonic acid, zinc acetate, manganese acetate and the like. These acid catalysts may be used alone or in combination of two or more. 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 because of their excellent activity. The acid catalyst may be added before the reaction or during the reaction.

Examples of the solvent used as necessary in Step 1 and Step 3 include monoalcohols such as methanol, ethanol, propanol; ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butane. Polyols such as diol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 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 ethyl methyl ether, ethylene glycol monophenyl ether, etc. Glycol ethers; 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. Can be mentioned. These solvents may be used alone or in combination of two or more. Among these solvents, 2-ethoxyethanol is preferable from the viewpoint of excellent solubility of the resulting compound.

The charge ratio [(a1)/(a2)] of the alkyl-substituted phenol (a1) to the aromatic aldehyde (a2) having a carboxyl group in the step 1 is such that the unreacted alkyl-substituted phenol (a1) can be removed and the product can be removed. 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, because the yield and the purity of the reaction product are excellent.

The charging 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 phenol resin for resist. 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, since a polymer having a high molecular weight is obtained.

As the method for isolating the aromatic compound (A) from the reaction solution in step 2, for example, a precipitate obtained by adding the reaction solution to a poor solvent (S1) in which the reaction product is insoluble or sparingly soluble After filtering off, the reaction product is dissolved and dissolved in a solvent (S2) which is also miscible with the poor solvent (S1), and the resulting precipitate is added to the poor solvent (S1) and the precipitate formed is filtered off. To be

Examples of the poor solvent (S1) used in this case include water; monoalcohols such as methanol, ethanol and propanol; aliphatic hydrocarbons such as n-hexane, n-heptane, n-octane and cyclohexane; toluene and xylene. And other aromatic hydrocarbons. Among these poor solvents (S1), water and methanol are preferable because they can efficiently remove the acid catalyst at the same time. On the other hand, examples of the solvent (S2) include monoalcohols such as methanol, ethanol, 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, polyols such as glycerin; 2-ethoxyethanol, Glycol ethers such as 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 ethyl methyl ether, ethylene glycol monophenyl ether; Examples thereof include cyclic ethers such as 3-dioxane and 1,4-dioxane; glycol esters such as ethylene glycol acetate; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone. When water is used as the poor solvent (S1), acetone is preferable as the (S2). The poor solvent (S1) and the solvent (S2) may be used alone or in combination of two or more.

When aromatic hydrocarbons such as toluene and xylene are used as the solvent in the above step 1 and step 3, the aromatic compound (A) produced by the reaction is dissolved in the solvent when heated at 80° C. or higher. By cooling as it is, crystals of the aromatic compound (A) are precipitated, so that the aromatic compound (A) can be isolated by filtering this. In this case, the poor solvent (S1) and the solvent (S2) may not be used.

The aromatic compound (A) represented by the above formula (1) can be obtained by the isolation method in the above step 2. The purity of the aromatic compound (A) is preferably 90% or more, more preferably 94% or more, and more preferably 98% or more, as calculated from the gel permeation chromatography (GPC) chart. Is particularly preferable. 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 later.

The weight average molecular weight (Mw) of the novolac 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 novolak type phenol resin (C) is measured by gel permeation chromatography (hereinafter abbreviated as “GPC”) under the following measurement conditions.

(GPC measurement conditions)
Measuring device: "HLC-8220 GPC" manufactured by Tosoh Corporation
Column: Showa Denko KK "Shodex KF802" (8.0mmΦ×300mm)
+ Showa Denko KK "Shodex KF802" (8.0mmΦ×300mm)
+ Showa Denko KK "Shodex KF803" (8.0mmΦ×300mm)
+ Showa Denko KK "Shodex KF804" (8.0mmΦ×300mm)
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: 0.5% by mass tetrahydrofuran solution in terms of resin solid content filtered with a microfilter (100 μl)
Standard sample: Monodisperse polystyrene below

(Standard sample: Monodisperse polystyrene)
Tosoh Corporation "A-500"
Tosoh Corporation "A-2500"
Tosoh Corporation “A-5000”
Tosoh Corporation "F-1"
Tosoh Corporation "F-2"
Tosoh Corporation "F-4"
Tosoh Corporation “F-10”
Tosoh Corporation “F-20”

[Metal atom forming metal salt]
Examples of the metal atom forming the metal salt with the novolac type phenol 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 added with a metal salt such as hydrochloride, nitrate or sulfate of a metal atom and/or a metal oxide while heating a composition containing the novolac type phenolic resin (C). It can be formed by 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, relative to 100 parts by mass of the novolac type phenol resin (C).

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

The alkali-soluble resin (D) may be any resin that is soluble in an alkaline aqueous solution, and cresol novolac resin is preferable. The cresol novolac resin is a novolac type phenol resin obtained by condensing a phenolic compound and an aldehyde compound as reaction raw materials, and is preferably selected from the group consisting of o-cresol, m-cresol and p-cresol. It is a resin using the above-mentioned phenolic compound as an essential reaction raw material.

As the phenol-based compound that is the reaction raw material of the cresol novolac resin, phenol or a phenol derivative other than cresol may be used together. Examples of phenol compounds other than cresol include phenol; 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, and the like. Xylenol; ethylphenol such as o-ethylphenol, m-ethylphenol, p-ethylphenol; butylphenol such as isopropylphenol, butylphenol, pt-butylphenol; p-pentylphenol, p-octylphenol, p-nonylphenol, p- Alkylphenols such as cumylphenol; halogenated phenols such as fluorophenol, chlorophenol, bromophenol, iodophenol; mono-substituted phenols such as p-phenylphenol, aminophenol, nitrophenol, dinitrophenol, trinitrophenol; 1-naphthol Condensed polycyclic phenols such as 2-naphthol; resorcin, alkylresorcin, pyrogallol, catechol, alkylcatechol, hydroquinone, alkylhydroquinone, phloroglucin, bisphenol A, bisphenol F, bisphenol S, polyhydroxyphenols such as dihydroxynaphthalene, etc. To be The phenolic compounds other than the cresol may be used alone or in combination of two or more.

When cresol and a phenolic compound other than cresol are used as reaction raw materials in the preparation of the alkali-soluble resin (D), the amount of the phenolic compound other than cresol used is 0.05 to 1. It is preferably in the range of 0 mol.

Examples of the aldehyde compound as a raw material of the cresol novolac resin include formaldehyde, paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, polyoxymethylene, chloral, hexamethylenetetramine, furfural, glyoxal, n-butyraldehyde, caproaldehyde, Examples include allyl aldehyde, benzaldehyde, crotonaldehyde, acrolein, tetraoxymethylene, phenylacetaldehyde, o-tolualdehyde, salicylaldehyde and the like. Of these, formaldehyde is preferred. The aldehyde compounds may be used alone or in combination of two or more.

When formaldehyde is used as the aldehyde compound that is the 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 in the preparation of the cresol novolac resin, the amount of the aldehyde compound other than formaldehyde used is 0.05 to 1.0 mol per 1.0 mol of the formaldehyde. A range is preferred.

The condensation reaction of 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, paratoluenesulfonic acid, zinc acetate, manganese acetate and the like. Among these, oxalic acid is preferable because it has excellent catalytic activity. The acid catalyst may be used alone or in combination of two or more. The acid catalyst may be charged before the reaction or added during the reaction.

The preparation ratio (molar ratio) of the phenolic compound and the aldehyde compound when preparing the cresol novolac resin is preferably in the range of 0.3 to 1.6 of aldehyde compound/phenolic compound, and 0.5 to 1. A range of 3 is more preferable.

As a specific example of the reaction of the phenolic compound and the aldehyde compound when preparing the cresol novolac resin, the phenolic compound and the aldehyde compound are heated to 60 to 140° C. in the presence of an acid catalyst to promote the polycondensation reaction, Then, a method of performing dehydration and demonomer under reduced pressure conditions can be mentioned.

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-trihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone and 2,3,6-trihydroxy. Benzophenone, 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'-hexahydroxybenzophenone and other polyhydroxybenzophenone compounds; 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′-dimethyl-{1-[4-[2-(3-methyl-4-hydroxyphenyl)-2-propyl] Phenyl]ethylidene}bisphenol and other bis[(poly)hydroxyphenyl]alkane compounds; tris(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-dihydroxyphenyl Tris(hydroxyphenyl)methanes such as methane or methyl substitution products thereof; 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-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-hydroxyphenyl Naphthoquinone-1,2-bis(cyclohexylhydroxyphenyl)(hydroxyphenyl)methanes or their methyl-substituted compounds such as methane and bis(5-cyclohexyl-2-hydroxy-4-methylphenyl)-4-hydroxyphenylmethane -Complete ester compound, partial ester compound, amidated product or partially amidated product with a sulfonic acid having a quinonediazide group such as diazide-5-sulfonic acid or naphthoquinone-1,2-diazido-4-sulfonic acid, orthoanthraquinonediazidesulfonic acid And so on. 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 100 because the good sensitivity is obtained and a desired pattern is obtained, and the total content of the novolac type phenol resin (C) and the alkali-soluble resin (D) is 100. The range of 3 to 50 parts by mass is preferable, and the range of 5 to 30 parts by mass is more preferable, with respect to parts by mass.

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, ethylene glycol monobutyl ether; diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, Diethylene glycol dialkyl ethers such as 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, propylene glycol monopropyl ether acetate Ketones such as acetone, methyl ethyl ketone, cyclohexanone and methyl amyl ketone; cyclic ethers such as dioxane; methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, Esters such as ethyl oxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, ethyl formate, ethyl acetate, butyl acetate, methyl acetoacetate, ethyl acetoacetate, etc. Are listed. These solvents (F) can 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 the solid content in the resist composition of the present invention can be obtained because a uniform coating film can be obtained by applying a fluidity of the composition by a coating method such as a spin coating method. It is preferable that the concentration is 15 to 65% by mass.

The resist composition of the present invention may contain a metal salt of a novolac type phenolic resin (C), and optionally an alkali soluble resin (D), a photosensitizer (E) and a solvent (F). ) Metal salts and optionally alkali-soluble resin (D), photosensitizer (E), solvent (F) and components other than components (C) to (F) (for example, surface activity of fillers, pigments, leveling agents, etc. Agent, an adhesion improver, and a dissolution accelerator), and may contain inevitable impurities as long as the effects of the present invention are not impaired.

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 excluding the solvent (F) is a novolac type phenol resin. It may comprise a metal salt of (C), and optionally an alkali-soluble resin (D), a photosensitizer (E) and components other than components (C) to (F).

The resist composition of the present invention was added with a novolac type phenolic resin (C), a metal salt, another alkali-soluble resin (D) optionally blended, a photosensitizer (E) and a solvent (F), and if necessary. It can be prepared by mixing various additives with stirring by a usual method to form a uniform liquid.

When a solid material such as a filler and a pigment is added to the resist composition of the present invention, it is preferable to disperse and mix it using a dispersing device such as a dissolver, a homogenizer, or a three roll mill. Further, in order to remove coarse particles and impurities, the composition can be filtered using a mesh filter, a membrane filter or the like.

[Pattern formation method]
The resist composition of the present invention can be used as a negative photoresist composition or a positive photoresist. The method for producing a pattern using the resist composition of the present invention comprises a step of forming a resist film using the resist composition of the present invention, a step of exposing the resist film, and a step of developing the exposed resist film. Developing with a liquid to form a pattern.

Formation of the resist film, exposure of the resist film, and development of the exposed resist film can be carried out 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-ray, electron beam and the like. 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 preferable.

Examples of the alkaline developer used for the development after exposure include inorganic alkaline substances such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and ammonia water; 1 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; tetramethylammonium hydroxide, tetraethylammonium hydroxy Aqueous alkaline solutions such as quaternary ammonium salts such as deuterium; cyclic amines such as pyrrole and pyrelidine can be used. If necessary, alcohol, a surfactant and the like can be appropriately added to these alkaline developers for use. The alkali concentration of the alkali developer is usually 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 is preferably used in 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.

The present invention will be specifically described below with reference to examples and comparative examples.

Synthesis Example 1 Synthesis of Phenolic Trinuclear Compound Containing Carboxylic Acid Into a 2000 ml four-necked flask equipped with a cooling tube, 293.2 g (2.4 mol) of 2,5-xylenol and 150 g (1 mol) of 4-formylbenzoic acid were charged. , Dissolved in 500 ml 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 mantle heater and reacted with stirring for 2 hours. After completion of the reaction, water was added to the obtained solution to reprecipitate a crude product. The crude product was redissolved in acetone and further reprecipitated with water, and the precipitate was filtered off and dried in vacuum to obtain 283 g of pale pink crystal precursor compound (A-1).

As a result of ¹³ C-NMR measurement of the obtained precursor compound (A-1), it was confirmed to be a compound represented by the following structural formula. The purity (GPC purity) calculated from the GPC chart was 95.3%. The GPC chart and the ¹³ C-NMR chart of the precursor compound (A-1) are shown in FIG. 1 and FIG. 2, respectively.

Synthesis Example 2 Synthesis of Phenolic Trinuclear Compound In a 2000 ml four-necked flask equipped with a cooling tube, 293.2 g (2.4 mol) of 2,5-xylenol and 122 g (1 mol) of 2-hydroxybenzaldehyde were charged and treated with 2-ethoxy. It was dissolved in 500 ml of ethanol. After adding 10 ml of sulfuric acid while cooling in an ice bath, the mixture was heated to 100° C. with a mantle heater and reacted with stirring for 2 hours. After completion of the reaction, water was added to the obtained solution to reprecipitate a crude product. The crude product was redissolved in acetone and reprecipitated with water, and the precipitate was filtered off and dried in vacuum to obtain 283 g of a white crystalline precursor compound (A′-2).

As a result of ¹³ C-NMR measurement of the obtained precursor compound (A′-2), it was confirmed to be a compound represented by the following structural formula. The purity (GPC purity) calculated from the GPC chart was 98.2%. A GPC chart and a ¹³ C-NMR chart of the precursor compound (A′-2) are shown in FIG. 3 and FIG. 4, respectively.

Production Example 1 Synthesis of carboxylic acid-containing novolak-type phenol resin In a 1000 ml four-necked flask equipped with a cooling tube, 188 g of the precursor compound (A-1) and 16 g of 92% paraformaldehyde were charged 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 with stirring for 4 hours. After completion of the reaction, water was added to the obtained solution to reprecipitate a crude product. The crude product was redissolved in acetone and further reprecipitated with water, and then the precipitate was filtered off and vacuum dried to obtain 182 g of an orange powder novolac type phenol resin (C-1). The obtained novolak type phenol resin (C-1) had a number average molecular weight (Mn) of 3946, a weight average molecular weight (Mw) of 8504, and a polydispersity (Mw/Mn) of 2.16. A GPC chart of the novolac type phenol resin (C-1) is shown in FIG.

Production Example 2 Synthesis of carboxylic acid-containing novolac-type phenol resin Instead of the precursor compound (A-1), 9.4 g (0.025 mol) of the precursor compound (A-1) and the precursor compound (A′-2) In the same manner as in Production Example 1 except that 8.7 g (0.025 mol) was used, 16.8 g of a novolac-type phenol resin (C-2) as a pale red powder was obtained. The obtained novolak type phenol resin (C-2) had a number average molecular weight (Mn) of 3331, a weight average molecular weight (Mw) of 6738, and a polydispersity (Mw/Mn) of 2.02. A GPC chart of the novolac type phenol resin (C-2) is shown in FIG.

Production Example 3 Synthesis of Novolac Resin In a 2 L 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, p-toluene. 2.5 g of sulfonic acid and 500 g of toluene were charged and the temperature was raised to 120° C. to carry out a demethanol reaction. The mixture was heated under reduced pressure, distilled, and distilled under reduced pressure at 230° C. for 6 hours to obtain 882 g of a pale yellow solid novolac resin (C′-3). The number average molecular weight (Mn) of the novolak resin (C′-3) was 1016, the weight average molecular weight (Mw) was 2782, and the polydispersity (Mw/Mn) was 2.74. A GPC chart of the novolac resin (C′-3) is shown in FIG.

Production Example 4 Synthesis of novolac resin In a 2 L four-necked flask equipped with a stirrer and a thermometer, 648 g (6 mol) of m-cresol, 432 g (4 mol) of p-cresol, 2.5 g (0.2 mol) of oxalic acid, 42 % Formaldehyde (492 g) was charged, and the temperature was raised to 100° C. for reaction. It was dehydrated to 200° C. under normal pressure, distilled, and distilled under reduced pressure at 230° C. for 6 hours to obtain 736 g of a pale yellow solid novolak resin (C′-4).
The GPC of the novolak resin (C′-4) had a number average molecular weight (Mn) of 1450, a weight average molecular weight (Mw) of 10316, and a polydispersity (Mw/Mn) of 7.116. A GPC chart of the novolac resin (C′-4) is shown in FIG.

Example 1
[Preparation of resin solution]
The novolak-type phenol resin (C-1) prepared in Production Example 1 and propylene glycol monomethyl ether acetate (PGMEA) were mixed at a mass ratio of novolac-type phenol resin (C-1):PGMEA=20:80 to obtain novolak. A PGMEA solution of the type phenolic resin (C-1) was prepared, and this solution was subjected to microfiltration with a 0.1 μm polytetrafluoroethylene disk filter to prepare a resin solution.

[Complex evaluation]
Resin obtained 30ml heat tube of the solution 5g and metal nitrate hydrate in a _{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) 3 · 9H} 2 O was added 0.2g each, were heated to 100 ° C. with shaking process. 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.
○: Immobilized gelation △: Viscous liquidation ×: No change in viscosity

Since immobilization gelation or viscous liquefaction was confirmed by the above evaluation, 1 g of a hydrochloric acid aqueous solution was further added, and the mixture was shaken at room temperature for 3 hours. The state of the metal nitrate hydrate-containing resin solution after the shaking treatment was evaluated according to the following criteria, and it was confirmed whether or not a metal salt structure was formed. Table 1 shows the results of sol evaluation.
○: Low viscosity liquid △: Viscous liquid ×: No change in state

From the results shown in Table 1, the novolac-type phenol resin (C-1) of Production Example 1 was prepared by adding a metal nitrate hydrate to form an immobile gel or a viscous liquid, and further adding an aqueous hydrochloric acid solution to form a low-viscosity liquid. It was confirmed that the metal salt structure was formed by the addition of metal nitrate hydrate.

Immobilized gelation or viscous liquid formation by addition of metal nitrate hydrate, and low viscosity liquid formation by addition of hydrochloric acid aqueous solution are due to formation of a crosslinked structure due to coordination bond between metal and novolak, and This behavior indicates that the decomposition of the crosslinked structure due to dissociation is reversible, and thus indicates that a metal salt of a carboxylic acid is 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 onto a 5-inch silicon wafer by a spin coater so as to have 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 the immersion in the developing solution was measured, and the value obtained by dividing the difference by 60 was taken as the alkali developability (ADR1 (Å/s)).

In the obtained resin solution, a sensitizer P-200 (manufactured by Toyo Gosei Co., Ltd.; 4,4′-[1) was added so that the novolac type phenol resin/P-200/PGMEA=20/5/75 (mass ratio). -[4-[1-(4-Hydroxyphenyl)-1methylethyl]phenyl]ethylidene]bisphenol 1 mol and 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride 2 mol) was added), This resin composition was applied onto a 5-inch silicon wafer by a spin coater so as to have 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 the immersion in the developing solution was measured, and the value obtained by dividing the difference by 60 was taken as the alkali developability (ADR2 (Å/s)).

[Heat resistance evaluation]
The obtained resin solution was applied onto a 5-inch silicon wafer by a spin coater so as to have 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 resin film was scraped off, the glass transition 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 lower Note that the Tg was measured by using a differential thermal scanning calorimeter (“Differential thermal scanning calorimeter (DSC) Q100” manufactured by TA Instruments Co., Ltd.). In a nitrogen atmosphere, the temperature range was −100 to 200° C., and the temperature rising rate was 10° C./min.

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 novolac type phenol resin (C-1). The results are shown in Table 1. For the novolac resin (C′-3) and the novolac resin (C′-4) resin solutions, no sol-formation was evaluated when there was no change in viscosity in gelation evaluation.

Claims (9)

A resist composition containing a metal salt of a novolac type phenolic resin (C), which contains 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 represent an integer of 0 to 4.
When R ₁ is a plurality, the plurality of R ₁ may be the same or different.
When R ₂ are a plurality, 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 moiety having at least one substituent selected from an alkoxy group, a halogen group and a hydroxyl group on the hydrocarbon group. ) The resist composition according to claim 1, wherein the metal salt is a carboxylic acid metal salt. The resist composition according to claim 1 or 2, wherein the metal atom of the metal salt is one or more selected from a calcium atom, a zinc atom, a copper atom and an iron atom. The aromatic compound (A) is a polycondensation product of a phenol compound, an aromatic aldehyde having a carboxyl group or a carboxyester group, and/or an aromatic ketone having a carboxyl group or a carboxyester group. Item 4. The resist composition according to any one of items 1 to 3. The resist composition according to claim 4, wherein the aromatic aldehyde having a carboxyl group is formylbenzoic acid. The resist composition according to any one of claims 1 to 5, wherein the aliphatic aldehyde (B) is formaldehyde and/or paraformaldehyde. Forming a resist film using the resist composition according to any one of claims 1 to 6;
Exposing the resist film,
A step of developing the exposed resist film with a developing solution to form a pattern. The pattern forming method according to claim 7, wherein the exposure is exposure with an electron beam or extreme ultraviolet rays. A method for manufacturing an electronic device, including the pattern forming method according to claim 7.

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