Novolac resin for resist agents and resist agent compositions

Abstract

This invention provides a novel novolac resin that offers a novel resist agent with pattern-forming ability capable of forming highly detailed patterns and high exposure sensitivity. [Solution] A novolac resin for resists having a polymerization structure represented by the following formula (1). [Formula 1] JPEG2026125491000013.jpg39142 In the above formula (1), R 1 R is selected from hydrogen atoms and protecting groups. 2 Each of these is independently selected from halogen atoms, R 3 R is selected from hydrogen atoms, alkyl groups, etc. 4 is selected from alkylene groups, d and e are each independently represented by integers 0 or 1, and m:n is in the range of 100:0 to 10:90.

Description

[Technical Field]

[0001] This disclosure relates to novolac resins for resists and resist compositions. [Background technology]

[0002] For example, Patent Document 1 describes a phenol resin for photoresists, which is obtained by reacting p-cresol (component a) or xylel and / or trimethylphenol (component b) with a benzoaldehyde compound under an acidic catalyst, and then adding one or more phenols selected from the group consisting of phenol, cresol, xylenol, and trimethylphenol with formaldehyde and reacting them under an acidic catalyst.

[0003] For example, Patent Document 2 describes a radiation-sensitive composition containing 1 to 80% by weight of solid components, wherein the sum of a polyphenol compound (A) synthesized by a condensation reaction between a predetermined aromatic ketone or aromatic aldehyde and a compound containing a predetermined phenolic hydroxyl group, a compound (B) having a structure in which an acid-dissociable functional group is introduced to the phenolic hydroxyl group of the polyphenol compound (A), and a dissolution accelerator (C) is 50 to 99.999% by weight of the total weight of the solid components.

[0004] For example, Patent Document 3 describes a resist material comprising a base polymer and a quencher, wherein the quencher is an ammonium salt compound consisting of an ammonium cation in which an aromatic ring substituted with an iodine atom is bonded to a nitrogen atom via a hydrocarbylene group having 1 to 20 carbon atoms, and an anion derived from a phenol compound substituted with an iodine atom or a bromine atom, and the ammonium salt compound is a compound represented by a predetermined formula (A). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-088197 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-041501 [Patent Document 3] Japanese Patent Application Laid-Open No. 2021-033262 [Summary of the Invention] [Problems to be Solved by the Invention]

[0006] In recent lithography techniques, due to the miniaturization of patterns and the shortening of the exposure light source wavelength, high exposure sensitivity and high pattern definition are required. However, for example, a novolak resin for a resist agent that can obtain sufficient sensitivity to a short-wavelength exposure light source is required more than the resist agent composition described in Patent Document 1. Also, a resin for a resist agent that can achieve higher pattern definition than the resist agent compositions described in Patent Documents 2 and 3 is required. In a resist agent composition, there is a so-called trade-off relationship between high pattern definition and improved exposure sensitivity, and a resin for a resist agent having a pattern forming ability to form a high-definition pattern and high exposure sensitivity is required.

[0007] The invention according to one aspect of the present application has been made in view of the above problems, and its object is to provide a novel novolak resin that can provide a novel resist agent having a pattern forming ability to form a high-definition pattern and high exposure sensitivity. [Means for Solving the Problems]

[0008] In order to solve the above problems, a novolak resin for a resist agent according to one aspect of the present disclosure is a novolak resin having a polymerization structure represented by the following formula (1); [Chemical Formula] In the above formula (1), R 1 are each independently selected from a hydrogen atom and a protecting group; R 2Each of these is independently selected from halogen atoms; R 3 Each of these groups is independently selected from a hydrogen atom, alkyl group, acyl group, allyl group, aryl group, carboxyl group, thiol group, ether group, ester group, nitro group, cyano group, amino group, and formyl group; R 4 Each of these is independently selected from alkylene groups having 1 to 20 carbon atoms; a1 to a4 are each independently represented by integers from 0 to 3; Satisfying 1 ≤ a1 + a2 ≤ 4 and 1 ≤ a3 + a4 ≤ 4; b1 and b2 are each independently represented by integers between 0 and 3; Satisfying 1 ≤ b1 + b2 ≤ 4; c1 and c2 are each independently represented by integers of 1 or 2; c3 and c4 are each independently represented by integers between 1 and 3; d and e are each independently represented by integers of 0 or 1; A novolac resin for resists, comprising a novolac resin in which m:n is within the range of 100:0 to 10:90.

[0009] A resist composition according to one aspect of the present disclosure comprises a novolac resin for resists according to one aspect of the present disclosure and a photoacid generator. [Effects of the Invention]

[0010] According to one aspect of this disclosure, a novel novolac resin can be provided that offers a novel resist agent having pattern-forming ability capable of forming highly detailed patterns and high exposure sensitivity. [Modes for carrying out the invention]

[0011] <Terminology> Where used herein, a numerical range indicated by "~" represents a range that includes the numbers before and after "~" as the minimum and maximum values, respectively.

[0012] <Novolak resin> The novolak resin according to one aspect of the present disclosure is a novolak resin having a polymerization structure represented by the following formula (1);

Chemical formula

[0013] The novolak resin according to one aspect of the present disclosure, in the polymerization structure represented by the above formula (1), R 2At least one of these atoms is selected from halogen atoms. This allows for the formation of highly detailed patterns on a resist film containing the novolac resin without impairing the high exposure sensitivity of the novolac resin to short-wavelength light sources. Therefore, the novolac resin according to one aspect of this disclosure is a novel novolac resin that resolves the trade-off between high exposure sensitivity and the ability to form highly detailed patterns, and can be suitably used in resist compositions.

[0014] Of the two monomer units that constitute the polymerization structure represented by formula (1), R 2 A monomer unit having R can be defined as a halogenated monomer unit, 2 Monomer units that do not possess can be defined as non-halogenated monomer units. The polymerization structure represented by formula (1) may be a polymerization structure in which halogenated monomer units and non-halogenated monomer units polymerize randomly.

[0015] In equation (1) above, R 1 Each of these is independently selected from a hydrogen atom and a protecting group. 1 R is a protecting group formed by substituting a hydrogen atom or a hydrogen atom of a hydroxyl group in a novolac resin, 1 R, which binds to oxygen 1 Examples of oxygen groups include acetal groups, acyloxy groups, and alkoxy groups. For example, an acetal group is the acetal group shown in (1a) below.

[0016] [ka]

[0017] In formula (1a), * represents a bond between the novolac resin and the carbon atom of the aromatic ring. 1 This can be described as an alkoxyalkylene residue in the acetal group shown in formula (1a), and this alkoxyalkylene residue is a group derived from an olefin ether compound, which will be described later.

[0018] In formula (1a), R 11 and R 12 Each is independently selected from a hydrogen atom and an alkylene group having 1 to 10 carbon atoms, R 11 and R 12 One of them may be a hydrogen atom, and the other may be a methyl group.

[0019] In formula (1a), R 13 R is selected from alkyl groups, and the number of carbon atoms constituting the alkyl group is represented by an integer from 1 to 30, more specifically, 13 More specifically, the alkyl groups represented by can include, for example, an ethyl group, a propyl group, an n-butyl group, an i-butyl group, a hexyl group, a cyclohexyl group, and a 2-ethylhexyl group.

[0020] In equation (1) above, R 1 When the acyl group is an acyl group constituting an acyloxy group, examples of such acyl groups include acyl groups having 2 to 15 carbon atoms, such as alkyl acyl groups like acetyl groups and aromatic acyl groups like benzoyl groups.

[0021] Also, R 1 If the alkyl group constituting the alkoxy group is an alkyl group having 1 to 15 carbon atoms, examples include alkyl groups.

[0022] R in equation (1) above 1 R including 1 The ratio of hydroxyl groups to protecting groups in the O group (also called the hydroxyl group protection rate) is preferably 100 mol% or less, more preferably 80 mol% or less, and most preferably 60 mol% or less, when the total of hydroxyl groups and protecting groups is taken as 100 mol%. Also, the R in formula (1) above 1 The ratio of hydroxyl groups to protecting groups in the O group should be 10 mol% or more, and preferably 20 mol% or more.

[0023] In equation (1) above, R 2Each of these is independently selected from halogen atoms, and the halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, with bromine atoms and iodine atoms being preferred, and iodine atoms being more preferred. 2 However, by using halogen atoms, preferably iodine atoms, the absorption of electron beams (EB) or short-wavelength light (e.g., extreme ultraviolet (EUV) light of 3 to 15 nm) in conventional novolac resins can be further enhanced. As a result, a novolac resin according to one embodiment can provide a high-definition pattern in a resist film containing the novolac resin while maintaining the exposure sensitivity of conventional EUV resist compositions.

[0024] R 3 Each of these groups is independently selected from a hydrogen atom, an alkyl group, an acyl group, an allyl group, an aryl group, a carboxyl group, a thiol group, an ether group, an ester group, a nitro group, a cyano group, an amino group, and a formyl group. Examples of alkyl groups include alkyl groups having 1 to 20 carbon atoms, and may be linear, branched, or cyclic alkyl groups, but are not limited to these. 3 However, if it is an acyl group, for example, R 3 You can choose from the same acyl groups as above. Also, R 3 For example, allyl groups such as vinyl groups and 1-propenyl groups; aryl groups such as phenyl groups and naphthyl groups; ether groups such as alkyl ether groups and aryl ether groups having 1 to 15 carbon atoms; and ester groups such as alkyl ester groups and aryl ester groups having 1 to 15 carbon atoms can be selected.

[0025] In equation (1) above, a1 to a4 are each independently represented by integers from 0 to 3, and it is desirable that 1 ≤ a1 + a2 ≤ 4, preferably 1 ≤ a1 + a2 ≤ 2, and more preferably a1 + a2 = 1. Similarly, it is desirable that 1 ≤ a3 + a4 ≤ 4, preferably 1 ≤ a3 + a4 ≤ 2, and more preferably a3 + a4 = 1.

[0026] Novolac resins have at least one R for each monomer unit that makes up the polymer structure. 1 It has, and the R1 R including 1 By selecting the oxygen group from hydroxyl groups and protecting groups, alkali developability can be imparted to the novolac resin.

[0027] In equation (1) above, b1 and b2 are each independently represented by integers between 0 and 3, and it is desirable that 1 ≤ b1 + b2 ≤ 4, preferably 1 ≤ b1 + b2 ≤ 2, and more preferably b1 + b2 = 1.

[0028] In equation (1) above, c1 and c2 may each be independently represented by an integer of 1 or 2, and c3 and c4 may each be independently represented by an integer between 1 and 3.

[0029] R 4 Each of these groups is independently selected from alkylene groups having 1 to 20 carbon atoms, such as the methylene group and the propylene group.

[0030] In formula (1) above, m:n is preferably in the range of 100:0 to 10:90, and within this range, the larger m is, the higher the exposure sensitivity to EB and EUV can be, and the larger n is, the higher the pattern formation ability by EB or EUV can be. From the viewpoint of balancing pattern formation ability by EB or EUV and exposure sensitivity, m:n is preferably in the range of 100:0 to 10:90, preferably in the range of 90:10 to 20:80, and more preferably in the range of 80:20 to 30:70.

[0031] The novolac resin having a polymer structure represented by formula (1) has a weight-average molecular weight of 500 or more, preferably 1000 or more, and more preferably 50000 or less, and more preferably 30000 or less. This improves the film-forming properties of the novolac resin and further enhances exposure sensitivity.

[0032] In this specification, unless otherwise specified, novolac resin means both or either phenol novolac resin and naphthol novolac resin.

[0033] In formula (1), d and e are each independently represented by integers of 0 or 1, and are more preferably 0. When d and e are 0, the novolac resin having the polymerization structure represented by formula (1) is a phenol novolac resin, and when d and e are 1, the novolac resin having the polymerization structure represented by formula (1) is a naphthol novolac resin. The novolac resin having the polymerization structure represented by formula (1) is more preferably selected from phenol novolac resins having the polymerization structure represented by the following formula (2).

[0034] [ka]

[0035] In equation (2) above, R 1 These are often independently selected from a hydrogen atom and a protecting group. R 2 Each of these atoms is preferably independently selected from hydrogen, bromine, and iodine atoms, and R 2 At least one of them is an iodine atom or a bromine atom, R 4 It is preferable to select from alkylene groups with 1 to 20 carbon atoms.

[0036] Novolac resin is R 1 R at the meta position of the O group 2 When the group is a halogen group, the detachment of the halogen group during the synthesis of the novolac resin is further prevented, while the polymerizability of the novolac resin is further enhanced. In formula (2) above, m:n is preferably in the range of 100:0 to 10:90 for the same reasons as for the novolac resin represented in formula (1).

[0037] In equation (2) above, R 1 These can be independently selected from a hydrogen atom and a protecting group, and the protecting group should be similar to that in formula (1).

[0038] Furthermore, for the same reasons as for novolac resin represented by formula (1), in formula (2), b1 is often an integer from 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0039] The phenol novolac resin having a polymer structure represented by formula (2) has a weight-average molecular weight of 500 or more, preferably 1000 or more, and more preferably 50000 or less, and more preferably 30000 or less. This improves the film-forming properties of the phenol novolac resin and further enhances exposure sensitivity.

[0040] <Method for manufacturing novolac resin> A novolac resin according to one aspect of this disclosure can be produced by condensing an aromatic compound and an aldehyde in an organic solvent using an acid catalyst. Monomers used as raw materials include halogenated compounds of aromatic compounds having phenolic hydroxyl groups and non-halogenated compounds of aromatic compounds having phenolic hydroxyl groups. In this specification, aromatic compounds having phenolic hydroxyl groups may be referred to as phenolic aromatic compounds.

[0041] The halides of phenolic aromatic compounds are monomers that form halogenated monomer units in the polymerization structure contained in novolac resins. Examples include halogenated phenols and halogenated naphthols, which can be used individually or in combination of two or more. Examples of halogenated phenols include halogenated phenols such as fluorophenol, chlorophenol, bromophenol, and iodophenol, as well as derivatives of these halogenated phenols. Iodophenol and bromophenol are preferred, and iodophenol is more preferred. Examples of iodophenols include phenol iodides such as m-iodophenol, p-iodophenol, and 3,5-diiodophenol; alkylphenol iodides such as 3-iodo-p-cresol and 3-iodo-p-octylphenol; and polyhydric phenol iodides such as 1,4-dihydroxy-3-iodobenzene, with m-iodophenol being preferred. Examples of bromophenols include phenol bromides such as m-bromophenol, p-bromophenol, and 3,5-dibromophenol; alkylphenol bromides such as 3-bromo-p-cresol and 3-bromo-p-octylphenol; and polyhydric phenol bromides such as 1,4-dihydroxy-3-bromobenzene. Examples of halogenated naphthols include fluoronaphthol, chloronaphthol, bromonaphthol, and iodonaphthol, as well as derivatives of these halogenated naphthols. Iodonaphthol and bromonaphthol are preferred, and iodonaphthol is more preferred. Examples of iodonaphthols include naphthol iodides such as 1-hydroxy-3-iodonaphthalene, 2-hydroxy-5-iodonaphthalene, and 2-hydroxy-6-methyl-5-iodonaphthalene; and polyhydric naphthol iodides such as 1,4-dihydroxy-3-iodonaphthalene, 2,6-dihydroxy-1-iodonaphthalene, 2,6-dihydroxy-1,5-diiodonaphthalene, and 1,4-dihydroxy-3-iodonaphthalene. Examples of bromonaphthols include naphthol iodides such as 1-hydroxy-3-bromonaphthalene, 2-hydroxy-5-bromonaphthalene, and 2-hydroxy-6-methyl-5-bromonaphthalene; and polyvalent naphthol iodides such as 1,4-dihydroxy-3-bromonaphthalene, 2,6-dihydroxy-1-bromonaphthalene, 2,6-dihydroxy-1,5-dibromonaphthalene, and 1,4-dihydroxy-3-bromonaphthalene.

[0042] Among the halogenated compounds of the phenolic aromatic compounds described above, it is preferable that the halogenated compound of the phenolic aromatic compound is a halogenated compound in which the meta position of the hydroxyl group is halogenated. This makes it possible to more effectively prevent the detachment of halogen atoms from the halogenated compound of the phenolic aromatic compound, and to more effectively prevent the halogen atoms bonded to the phenolic aromatic compound from inhibiting the polymerization of the novolac resin at the ortho or para position of the hydroxyl group.

[0043] Non-halogenated phenolic aromatic compounds are monomers that form non-halogenated monomer units of the polymerization structure contained in novolac resins, and examples include phenols and their derivatives, such as: phenols; cresols such as o-cresol, m-cresol, and p-cresol; xylenols such as 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, and 3,5-xylenol; ethylphenols such as o-ethylphenol, m-ethylphenol, and p-ethylphenol; isopropylphenol, butylphenol, and pt-butylphenol. Examples include butylphenols such as p-pentylphenol, p-octylphenol, p-nonylphenol, and p-cumylphenol; alkylphenols such as p-pentylphenol, p-octylphenol, p-nonylphenol, and p-cumylphenol; monosubstituted phenols such as p-phenylphenol, aminophenol, nitrophenol, dinitrophenol, and trinitrophenol; condensed polycyclic phenols such as 1-naphthol and 2-naphthol; and polyhydric phenols such as resorcinol, alkylresorcinol, pyrogallol, catechol, alkylcatechol, hydroquinone, alkylhydroquinone, phloroglucin, bisphenol A, bisphenol F, bisphenol S, and dihydroxynaphthalene. These other phenols or their derivatives can be used individually or in combination of two or more.

[0044] Furthermore, the amount of halogenated and non-halogenated phenolic aromatic compounds used should be such that the ratio of halogenated phenolic aromatic compounds to phenol and non-halogenated monomer units is within the range of 100:0 to 10:90.

[0045] Examples of aldehyde compounds used as raw materials for novolac resin include formaldehyde, paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, polyoxymethylene, chloral, hexamethylenetetramine, furfural, glyoxal, n-butyraldehyde, caproaldehyde, allylaldehyde, benzaldehyde, crotonaldehyde, acrolein, tetraoxymethylene, phenylacetaldehyde, o-tolualdehyde, and salicylaldehyde. These aldehyde compounds can be used individually or in combination of two or more. Furthermore, it is preferable to use formaldehyde as a raw material for the novolac resin, and formaldehyde may be used in combination with other aldehyde compounds. When using formaldehyde in combination with other aldehyde compounds, it is preferable that the amount of the other aldehyde compound used be in the range of 0.05 to 1 mole per mole of formaldehyde.

[0046] 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, p-toluenesulfonic acid, citric acid, trifluoroacetic acid, acetic acid, zinc acetate, and manganese acetate. These acid catalysts can be used individually or in combination of two or more. Among these acid catalysts, p-toluenesulfonic acid is preferred due to its excellent catalytic activity. The acid catalyst may be added before the reaction or during the reaction.

[0047] Examples of solvents include monoalcohols such as methanol, ethanol, and propanol; polyols such as 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, and glycerin; glycol ethers such as 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, and propylene glycol methyl ether; cyclic ethers such as 1,3-dioxane and 1,4-dioxane; glycol esters such as propylene glycol 1-monomethyl ether 2-acetate; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; and aromatic hydrocarbons such as toluene and xylene. These solvents can be used individually or in combination of two or more. Among these solvents, propylene glycol methyl ether is preferred due to its excellent solubility of the resulting compound.

[0048] The reaction temperature during the synthesis of novolac resin is not particularly limited and can be within the range of 50 to 150°C.

[0049] Known protecting groups can be introduced into novolac resins. Compounds for forming acetal groups include olefin ether compounds in which an alkoxy group is ether-bonded to the carbon constituting the unsaturated double bond of an olefin, and preferably vinyl ether compounds. The vinyl ether compounds may be alkyl-containing vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, tert-butyl vinyl ether, 4-cyclopentyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, and cyclohexylmethyl vinyl ether, and may be aromatic-containing vinyl ether compounds such as phenyl vinyl ether and benzyl vinyl ether.

[0050] Besides vinyl ether compounds, other examples of olefin ether compounds include 1-methoxypropylene, 2-methoxy-2-butene, 2-methoxy-3-methyl-2-butene, and 2-(ethenyloxy)bicyclo[2.2.1]heptane.

[0051] The amount of olefin ether compound used when introducing acetal groups should be appropriately determined according to the amount of novolac resin used, the amount of hydroxyl groups present in the novolac resin, and the desired modification rate. The amount of hydroxyl groups present in the novolac resin can be, for example, 13 The integral value can be calculated by taking the ratio of the integral value at the peak of the carbon atom to which the hydroxyl group is attached in the novolac resin, as measured by 13C-NMR, to the integral value at the peak of a specific carbon atom derived from the acetal group.

[0052] <Resistant composition> A resist composition according to one aspect of this disclosure may contain a novolac resin according to one aspect of this disclosure as a base resin and a photoacid generator as a photosensitive agent. The novolac resin has at least a portion of its hydroxyl groups protected by a protecting group and contains a photoacid generator, which makes it suitable for use as, for example, a positive-type photoresist composition. The resist composition further preferably contains an organic solvent and a quencher.

[0053] Examples of novolac resins and preferred embodiments of the resist composition according to one aspect of this disclosure have already been described and will not be repeated here.

[0054] The photosensitive agent contained in a resist composition according to one aspect of this disclosure is typically a photoacid generator. The photosensitive agent may be a single type or a combination of two or more types.

[0055] The photoacid generator can be any known photoacid generator and is not limited to it, but examples include onium salt-based photoacid generators, diazomethane derivatives, nitrobenzyl sulfonate derivatives, and disulfone-based acid generators. The acid generator may be used alone or in combination of two or more acid generators.

[0056] Examples of onium salt-based acid generators include diphenyliodonium trifluoromethanesulfonate, (4-methoxyphenyl)phenyliodonium trifluoromethanesulfonate, bis(p-tert-butylphenyl)iodonium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate, (4-methoxyphenyl)diphenylsulfonium trifluoromethanesulfonate, (4-methylphenyl)diphenylsulfonium nonafluorobutanesulfonate, (p-tert-butylphenyl)diphenylsulfonium trifluoromethanesulfonate, diphenyliodonium nonafluorobutanesulfonate, bis(p-tert-butylphenyl)iodonium nonafluorobutanesulfonate, and triphenylsulfonium nonafluorobutanesulfonate. Among these, triphenylsulfonium trifluoromethanesulfonate is preferred in terms of solubility in solvents. These onium salt-based acid generators may be used individually or in combination of two or more.

[0057] Examples of diazomethane derivatives include bisarylsulfonyl diazomethanes such as bis(benzenesulfonyl)diazomethane and bis(p-toluenesulfonyl)diazomethane; and bisalkylsulfonyl diazomethanes such as bis(cyclohexylsulfonyl)diazomethane.

[0058] Other examples of acid generators include nitrobenzyl sulfonate derivatives such as p-toluenesulfonic acid 2,6-dinitrobenzyl and p-toluenesulfonic acid 2,4-dinitrobenzyl; bissulfone derivatives such as bisnaphthylsulfonylmethane; and sulfonic acid ester derivatives of N-hydroxyimide compounds such as N-hydroxysuccinidomethanesulfonic acid ester, N-hydroxysuccinidomitetrifluoromethanesulfonic acid ester, N-hydroxysuccinidomitep-toluenesulfonic acid ester, and N-hydroxynaphthalimidemethanesulfonic acid ester.

[0059] The content of the novolac resin in the resist composition is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, and even more preferably 0.5% by weight or more, based on the total weight of the resist composition. Furthermore, in terms of reducing the viscosity of the resist composition and improving coating properties, the content of the novolac resin is preferably 50% by weight or less, more preferably 40% by weight or less, and even more preferably 20% by weight or less.

[0060] The amount of photoacid generator contained in the resist composition is preferably 0.1 parts by weight or more, and more preferably 1.0 part by weight or more, based on 100 parts by weight of novolac resin. Furthermore, the amount of photosensitive agent contained in the resist composition is preferably 30 parts by weight or less, and more preferably 5.0 parts by weight or less, based on 100 parts by weight of novolac resin.

[0061] [Quencher] The resist composition preferably contains a quencher. The inclusion of a quencher in the resist composition suppresses the rapid diffusion rate of acid generated from the photoacid generator in a film containing a novolac resin as the base resin. This improves the resolution of the pattern when the film containing the novolac resin is exposed. Therefore, it is possible to reduce the sensitivity change after exposure, which is environment-dependent, and improve the alignment of exposure conditions and the pattern profile.

[0062] Quenchers include nitrogen-containing organic compounds, which include aliphatic amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, carbamates, and the like. Specifically, aliphatic amines include trimethylamine, diethylamine, triethylamine, di-n-propylamine, tri-n-propylamine, triisopropylamine, tripentylamine, trioctylamine, diethanolamine, and triethanolamine, with trioctylamine being particularly preferred.

[0063] Aromatic amines include, for example, aniline and its derivatives such as aniline, N-methylaniline, and N-ethylaniline. Heterocyclic amines include pyrrole, oxazole, imidazole, pyrazole, furazan, pyrroline, pyrrolidine, imidazoline, and its derivatives. Derivatives of pyrrolidine include N-methylpyrrolidine, pyrrolidinone, and N-methylpyrrolidone.

[0064] Examples of nitrogen-containing compounds having a carboxyl group include aminobenzoic acid, and examples of nitrogen-containing compounds having a sulfonyl group include 3-pyridinesulfonic acid and pyridinium p-toluenesulfonate. Examples of nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, and alcoholic nitrogen-containing compounds include 2-hydroxypyridine, 2-aminoethanol, 3-amino-1-propanol, and 4-amino-1-butanol.

[0065] The amount of quencher can be appropriately designed depending on the type of novolac resin and photosensitive agent, and is not limited, but for example, it is preferably 1 to 30 ppm and more preferably 5 to 15 ppm relative to the novolac resin contained in the resist composition.

[0066] [Other ingredients] A resist composition according to one aspect of this disclosure may contain, to the extent that its effect is not impaired, other components such as a diluent; a crosslinking agent; a surfactant; a reaction terminating agent; and other additives such as adhesion aids, fillers, and water-soluble resins. The other components may be one or a combination of two or more.

[0067] (Diluting solvent) The diluent solvent included in the resist composition is not limited, but is often an organic solvent, and preferably an amphiphilic solvent. Examples of amphiphilic solvents include ethylene glycol alkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether; diethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, and diethylene glycol dibutyl ether; ethylene glycol alkyl ether acetates such as methyl cellosolve acetate and ethyl cellosolve acetate; and propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether. Examples include propylene glycol alkyl ether acetates such as propyl ether acetate and propylene glycol monopropyl ether acetate; ketones such as acetone, methyl ethyl ketone, cyclohexanone, and methyl amyl ketone; cyclic ethers such as dioxane; and esters such as methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl oxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, ethyl formate, ethyl acetate, butyl acetate, methyl acetoacetate, and ethyl acetoacetate. These solvents can be used individually or in combination of two or more.

[0068] (Surfactants) By including an appropriate amount of surfactant in the resist composition, the surface tension of the resist composition can be arbitrarily adjusted, improving the leveling properties during coating and enhancing the uniformity of the coating film thickness.

[0069] Examples of surfactants included in the resist composition include fluororesin-based surfactants, silicone-based surfactants, polyoxyalkylene ether-based surfactants, and acrylic resin-based surfactants.

[0070] In the resist agent composition, the surfactant content is preferably 0.01 parts by weight or more, and more preferably 0.30 parts by weight or more, based on 100 parts by weight of the novolac resin content. Furthermore, in the resist agent composition, the surfactant content is preferably 10.00 parts by weight or less, and more preferably 5.00 parts by weight or less, based on 100 parts by weight of the novolac resin content.

[0071] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure.

[0072] [summary] [1] A novolac resin for resists according to an aspect of the present disclosure [1] is a novolac resin having a polymerization structure represented by the following formula (1): [ka] In equation (1) above, R 1 Each is independently selected from a hydrogen atom and a protecting group; R 2 Each of these is independently selected from halogen atoms; R 3 Each of these groups is independently selected from a hydrogen atom, alkyl group, acyl group, allyl group, aryl group, carboxyl group, thiol group, ether group, ester group, nitro group, cyano group, amino group, and formyl group; R 4 Each of these is independently selected from alkylene groups having 1 to 20 carbon atoms; a1 to a4 are each independently represented by integers from 0 to 3; Satisfying 1 ≤ a1 + a2 ≤ 4 and 1 ≤ a3 + a4 ≤ 4; b1 and b2 are each independently represented by integers between 0 and 3; Satisfying 1 ≤ b1 + b2 ≤ 4; c1 and c2 are each independently represented by integers of 1 or 2; c3 and c4 are each independently represented by integers between 1 and 3; d and e are each independently represented by integers of 0 or 1; It contains novolac resin in which m:n is within the range of 100:0 to 10:90.

[0073] [2] The novolac resin for resists according to aspect [2] of the present disclosure is a novolac resin represented by formula (1) having a polymerization structure represented by the following formula (2) in aspect [1]; [ka] In equation (2) above, R 1 Each is independently selected from a hydrogen atom and a protecting group; R 2 These are independently selected from hydrogen atoms and iodine atoms; R 2 At least one of them is an iodine atom or a bromine atom; b1 is represented by an integer between 1 and 3; R 4 Each of these is more preferably independently selected from alkylene groups having 1 to 20 carbon atoms.

[0074] [3] The novolac resin for resists according to aspect [3] of the present disclosure, in aspect [1] or [2], the R 1 Of the groups represented by , it is more preferable that the proportion of protecting groups is 100 mol% or less.

[0075] [4] In any of the embodiments [4] of the present disclosure, the novolac resin for resists has a weight-average molecular weight in the range of 500 to 50000.

[0076] [5] A resist composition according to an embodiment of the present disclosure[5] comprises a novolac resin for resists according to any of embodiments[1] to[4] and a photoacid generator.

[0077] [6] The resist composition according to an embodiment of the present disclosure[6] is more preferably further comprising a quencher in the embodiment[5]. [Examples]

[0078] One embodiment of this disclosure is described below. [1] Preparation of base polymer [1-1] Base polymer 1 and base polymer 2 The following resins were used for base polymers 1 and 2. • Base polymer 1 Phenolic novolac resin GP (Mw: 7000, manufactured by Gun-ei Chemical Industry Co., Ltd.) • Base polymer 2 Polyhydroxystyrene resin G-HS (Mw: 15000, manufactured by Gun-ei Chemical Industry Co., Ltd.)

[0079] [1-2] Base polymer 3 and base polymer 4 Base polymers 3 and 4 were synthesized according to the following procedure.

[0080] (Synthesis of base polymer 3) A reaction vessel equipped with a thermometer, stirrer, and condenser was charged with 175.0 g of m-iodophenol, 35.83 g of 50% formaldehyde, 1.513 g of p-toluenesulfonic acid, and 49.36 g of propylene glycol monomethyl ether (PGME) to prepare the reaction mixture. The reaction mixture was then heated to 100°C and the reaction was carried out. Subsequently, the product was extracted by adding methyl isobutyl ketone to the reaction mixture, and then washed and fractionated by adding water. After that, the solvent was replaced with propylene glycol monomethyl ether acetate (PGMEA). This yielded an iodide novolac type phenol resin with an m-iodophenol to phenol ratio (mI-phe:phe) of 100:0.

[0081] (Synthesis of base polymer 4) A reaction vessel equipped with a thermometer, stirrer, and condenser was charged with 130.0 g of m-iodophenol, 55.6 g of phenol, 53.24 g of 50% formaldehyde, 0.225 g of p-toluenesulfonic acid, and 52.35 g of PGME to prepare the reaction mixture. The reaction mixture was then heated to 95°C and the reaction was carried out. After the reaction, the product was extracted by adding methyl isobutyl ketone, and then washed and fractionated by adding water. Subsequently, the solvent was replaced with PGMEA. This yielded an iodide novolac type phenol resin with a m-iodophenol to phenol ratio (mI-phe:phe) of 50:50.

[0082] [2] Introduction of protecting groups into the base polymer The protective group was introduced to base polymer 3 according to the following procedure. In a reaction vessel equipped with a thermometer, stirrer, and condenser, 51.90 g of base polymer 3 synthesized according to the above procedure and 48.1 g of PGMEA were charged. A total of 0.2528 g of trifluoroacetic acid was added in three separate additions, and stirring was continued for about 10 minutes. This obtained a reaction solution for introducing the protecting group. Subsequently, a solution obtained by dissolving 7.59 g of ethyl vinyl ether (EVE) in PGMEA was added to the reaction solution for introducing the protecting group in eight separate additions, and the reaction was carried out at 30°C. After that, the mixture was neutralized with triethylamine, and then washed with ethyl acetate (including acetone if necessary) and water to obtain base polymer 3 with the introduced protecting group.

[0083] Using a similar procedure, protective groups were introduced into each base polymer as shown in Table 1 below.

[0084] [Table 1]

[0085] The analytical method for molecular weight (Mw) and the measurement method for protection rate, as shown in Table 1, are as follows.

[0086] [Weight average molecular weight (Mw)] The weight-average molecular weight (Mw) was evaluated by gel permeation chromatography (GPC). (Measurement conditions) • GPC device: HLC8120GPC (manufactured by Tosoh Corporation) • Analysis columns: TSKgel G3000H (1 tube) TSKgel G2000H (2 tubes) TSKgel is a registered trademark of Tosoh Corporation. Mobile phase: Tetrahydrofuran (THF)

[0087] [Protection rate] The degree of protection of the phenolic hydroxyl groups in the base polymer by the protecting group was measured by NMR, and the protection rate of the hydroxyl groups (the rate of introduction of the protecting group) was calculated. (Measurement conditions) ·NMR device: ECZ-500R / s1 (manufactured by JEOL RESONANCE) • Measured radionuclides: 13 C • Dilution solvent: Acetone-d6

[0088] [3] Preparation of resist composition [3-1] Examples 1 and 2, and Comparative Examples 1 and 2 The resist agent compositions for Examples 1 and 2, and the resist agent compositions for Comparative Examples 1 and 2 were prepared using the composition ratios shown in Table 2 below. In preparing the resist compositions, the resin solids content was adjusted for each PGMEA solution of the base polymer into which the protecting group was introduced as shown in Table 1, as shown in Table 2. With the resin solids content set to 100% by weight, a photoacid generator (PAG) and a quencher were added, respectively.

[0089] [Table 2]

[0090] The photoacid generator and quencher added to the resist agents in Examples 1 and 2 and Comparative Examples 1 and 2 are as follows. Photoacid generator: Triphenylsulfonium trifluoromethanesulfonate Quencher: Trioctylamine Resin solids

[0091] [3-2] Resistant composition of Comparative Example 3 As Comparative Example 3, the following resist composition was used. • Comparative Example 3 EUV-8 (manufactured by Lithotech Japan Co., Ltd.) Composition: Lactone skeleton acrylic resin (protecting group: adamantyl group, PAG: TPS-PSBF, 8% by weight (resin ratio))

[0092] [3] Each evaluation [3-1] Sensitivity evaluation by EB exposure The resist compositions shown in Table 2 above were spin-coated onto silicon wafers and pre-baked using a hot plate at 110°C for 90 seconds. This produced resist films with a thickness of 100 nm. The fabricated resist films were then exposed using an EB lithography machine ELS-G100-SP (manufactured by Elionix, 100 keV) at exposure levels of 5 to 250 μC / cm². 2 The resist film was exposed to light. Next, post-bake (PEB) was performed using a hot plate at 100°C for 60 seconds, followed by development using a 2.38% by mass TMAH aqueous solution at 23°C for 60 seconds. Afterward, the remaining film thickness of the developed resist film was measured. Furthermore, the film thickness measurement results against exposure were plotted for each resist film, and the Eth Calculator software was used to calculate the Eth 60 The dose amount (unit: μC / cm³) obtained from this calculation is calculated. 2 ) was evaluated as sensitivity.

[0093] Furthermore, the pattern formed on the resist film by development was observed using a scanning electron microscope S-4800 (manufactured by Hitachi High-Technologies Corporation), and the roughness of the pattern was evaluated. The evaluation criteria for roughness are shown below. A: The edge shape is smooth and straight, without any bumps or irregularities. B: There are slight irregularities in the edge shape. C: The edge shape is uneven. Table 3 shows the results of the sensitivity evaluation using EB exposure.

[0094] [Table 3]

[0095] As shown in Table 3, the resist films formed with the resist agent compositions of Examples 1 and 2 showed higher contrast (high resolution) upon EB irradiation compared to the resist films formed with the resist agent compositions of Comparative Examples 1 and 2, which are conventional resist materials. In particular, the resist film of Example 2 was confirmed to be highly sensitive.

[0096] [3-2] Sensitivity evaluation by EUV exposure The resist compositions of Comparative Example 1, Example 1, and Example 2, as well as the resist composition of Comparative Example 3, were spin-coated onto silicon wafers and pre-baked using a hot plate at 110°C for 90 seconds. This produced resist films with a thickness of 100 nm. The fabricated resist films were exposed using an EUV lithography machine EUVES-9000 (manufactured by Lithotech Japan). The exposure dose was 0-6 mJ / cm². 2 Post-bake (PEB) was performed using a hot plate at 100°C for 60 seconds. Subsequently, development was carried out using a 2.38 mass% TMAH aqueous solution at 23°C for 60 seconds. The remaining film thickness of the developed resist film was then measured. Furthermore, similar to the sensitivity obtained by EB exposure, Eth Calculator software was used to measure Eth 60 The dose was calculated and the resulting dose was evaluated as sensitivity. The results of the sensitivity evaluation using EUV exposure are shown in Table 4.

[0097] [Table 4]

[0098] As shown in the results in Table 4, the resist films obtained from the resist compositions of Examples 1 and 2 were found to have higher sensitivity to EUV light compared to the resist film of Comparative Example 3, which was formed from a conventional acrylic resin-based positive resist composition.

[0099] As described above, the novolac resin and photoresist composition for photoresists disclosed herein have good sensitivity, LER, and pattern shape, and have been confirmed to be suitable for use in the manufacture of miniaturized circuits in semiconductor integrated circuits. [Industrial applicability]

[0100] A novolac resin for resists and a resist composition according to one aspect of this disclosure can be suitably used, for example, in the manufacture of semiconductor integrated circuits equipped with miniaturized circuits that are patterned using high-energy rays such as electron beams and extreme ultraviolet rays.

Claims

1. Novolac resin having a polymerization structure represented by the following formula (1): 【Chemistry 1】 In the above formula (1), R １ These are independently selected from a hydrogen atom and a protecting group; R ２ Each of these is independently selected from halogen atoms; R ３ Each of these groups is independently selected from a hydrogen atom, alkyl group, acyl group, allyl group, aryl group, carboxyl group, thiol group, ether group, ester group, nitro group, cyano group, amino group, and formyl group; R ４ Each of these is independently selected from alkylene groups having 1 to 20 carbon atoms; a1 to a4 are each independently represented by integers from 0 to 3; Satisfying 1 ≤ a1 + a2 ≤ 4 and 1 ≤ a3 + a4 ≤ 4; b1 and b2 are each independently represented by integers between 0 and 3; Satisfying 1 ≤ b1 + b2 ≤ 4; c1 and c2 are each independently represented by integers of 1 or 2; c3 and c4 are each independently represented by integers between 1 and 3; d and e are each independently represented by integers of 0 or 1; A novolac resin for resists, comprising a novolac resin in which m:n is in the range of 100:0 to 10:

90.

2. A novolac resin in which the polymerization structure represented by formula (1) is selected from the polymerization structures represented by the following formula (2): 【Chemistry 2】 In the above formula (2), R １ These are independently selected from a hydrogen atom and a protecting group; R ２ Each of these is independently selected from hydrogen, bromine, and iodine atoms; R ２ At least one of them is an iodine atom or a bromine atom; b1 is represented by an integer between 1 and 3; R ４ The novolac resin for resist agents according to claim 1, wherein each is independently selected from alkylene groups having 1 to 20 carbon atoms.

3. The above-mentioned R １ The novolak resin for a resist agent according to Claim 1 in which a ratio of the protecting group among the groups represented by the above is 100 mol% or less.

4. The novolac resin for resist agents according to claim 1, wherein the weight-average molecular weight is in the range of 500 to 50,000.

5. A novolac resin for resist agents according to any one of claims 1 to 4, A resist composition comprising a photoacid generator.

6. Furthermore, the resist composition according to claim 5, further comprising a quencher.

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