Resist underlayer film forming composition

Abstract

The present invention provides: a resist underlayer film forming composition which exhibits excellent filling properties and planarization properties with respect to a substrate with level difference, while having high storage stability of a polymer that serves as a main component of a resist underlayer film; a resist pattern forming method which uses this resist underlayer film forming composition; and a method for producing a semiconductor device, the method using this resist underlayer film forming composition.　The present invention provides a resist underlayer film forming composition which contains (a) a thermal acid generator that is represented by formula (I), (b) a polymer that contains an aromatic ring, (c) a base B2 and (d) a solvent. In formula (I), A1 represents an optionally substituted linear, branched or cyclic, saturated or unsaturated aliphatic hydrocarbon group, or an optionally substituted aromatic ring residue. In formula (1), B1 represents a counter base; and at least one base among B1 and B2 has a higher pKa than pyridine.

Description

Resist underlayer film-forming composition

[0001] The present invention relates to a resist underlayer film-forming composition suitable for lithography in semiconductor substrate processing, a resist underlayer film obtained from the resist underlayer film-forming composition, a method for forming a resist pattern using the resist underlayer film-forming composition, and a method for manufacturing a semiconductor device using the composition.

[0002] In recent years, in the lithography process for manufacturing semiconductor devices, semiconductor process materials, including resist underlayer films, are required to have various excellent material properties, as well as further improvement in the quality of the resist underlayer film-forming composition in terms of stability. For example, when there are steps on the underlying substrate to be processed, or when densely patterned areas and non-patterned areas exist on the same wafer, it is necessary to flatten the film surface with an underlayer film. Resins suitable for such purposes have been proposed (Patent Document 1). Meanwhile, in order to form such a thermosetting film, resist underlayer film-forming compositions contain, in addition to the polymer resin that is the main component, a crosslinkable compound (crosslinking agent) and a catalyst for accelerating the crosslinking reaction (crosslinking catalyst). With regard to the issue of flattening the film surface with an underlayer film, these components have not yet been fully investigated. Furthermore, recently, a new problem has arisen in that the crosslinking catalyst or solvent used in the resist underlayer film-forming composition denatures the crosslinking agent and the polymer resin that is the main component of the resist underlayer film, and there is a need to suppress such denature. Patent Document 2 discloses a compound of the formula (A － ) (BH) ＋ In this case, A － is an anion of an organic or inorganic acid having a pKa of 3 or less, (BH) ＋ Patent Document 3 discloses an ionic thermal acid generator which is a monoprotonated form of a nitrogen-containing base B having a pKa between 0 and 5.0 and a boiling point of less than 170° C. Specifically, the invention discloses a combination of perfluorobutanesulfonate with ammonium, pyridinium, 3-fluoropyridinium, or pyridazinium. Patent Document 3 discloses an ionic thermal acid generator represented by the formula X － YH ＋discloses a thermal acid generator in which X is an anion component and Y is a substituted pyridine. Specifically, a combination of methylbenzenesulfonate and fluoropyridinium or trifluoromethylpyridinium is described. Patent Document 4 discloses a thermal acid generator containing a sulfonic acid component without a hydroxyl group and a pyridinium component having a ring substituent. Specifically, a combination of methylbenzenesulfonate and methylpyridinium, methoxypyridinium, or trimethylpyridinium is described. Patent Document 5 discloses a thermal acid generator containing triethylamine paratoluenesulfonate, ammonium paratoluenesulfonate, ammonium mesitylenesulfonate, ammonium dodecylbenzenesulfonate, or dimethylamine paratoluenesulfonate. Patent Document 6 discloses a thermal acid generator containing various sulfonic acids and NH ４ ＋ or a primary, secondary, tertiary, or quaternary ammonium ion are disclosed.

[0003] International Publication No. 2014 / 024836 Japanese Patent No. 6334900 Japanese Patent Application Laid-Open No. 2019-56903 Japanese Patent No. 6453378 Japanese Patent No. 4945091 Japanese Patent No. 6256719

[0004] However, the thermal acid generators disclosed in the prior art are intended to improve resist shape, and there is no mention whatsoever of their ability to fill uneven substrates or planarize uneven substrates. Furthermore, while the invention discloses the relationship between storage stability and sublimates, there is no specific evaluation or mention of the thermal acid generator and polymer denaturation, and no study has been conducted on their ability to fill uneven substrates or planarize uneven substrates. In recent years, it has become clear that the above-mentioned thermal acid generators cannot suppress polymer denaturation unless an appropriate amine component is selected. Therefore, there is a need for a thermal acid generator that can suppress polymer denaturation while simultaneously achieving the ability to fill uneven substrates and planarize uneven substrates. The problem to be solved by the present invention is to provide a resist underlayer film-forming composition that has excellent ability to fill uneven substrates and planarize uneven substrates, and that has high storage stability of the polymer, which is the main component of the resist underlayer film; a method for forming a resist pattern using the resist underlayer film-forming composition; and a method for manufacturing a semiconductor device using the composition.

[0005] The present invention includes the following: [1] (a) a compound represented by the following formula (1): (b) a polymer containing an aromatic ring; and (c) one or more bases B. ２ and (d) a solvent, １ is an optionally substituted linear, branched, or cyclic saturated or unsaturated aliphatic hydrocarbon group, or an optionally substituted aromatic ring residue; in formula (1), n ​​represents the number of sulfonate anion groups and is 1 or 2; in formula (1), B １ represents one or more counter bases, and is a mono-acid base or represents the mono-acid base moiety of a di-acid base or tri-acid base; A １ and B １ may be linked to B via a single bond or a linking group; １ and B ２A resist underlayer film-forming composition, wherein at least one base has a pKa greater than that of pyridine. [2] The resist underlayer film-forming composition according to [1] above, wherein the aromatic ring-containing polymer is a novolak resin. [3] The aromatic ring-containing polymer is a novolak resin including a unit structure having an aromatic ring which may have a substituent, wherein the aromatic ring: (i) contains a heteroatom in the substituent on the aromatic ring, (ii) contains multiple aromatic rings in the unit structure, at least two of the aromatic rings are connected to each other by a linking group which contains a heteroatom, or (iii) the aromatic ring is an aromatic heterocycle, or an aromatic ring which forms a fused ring with one or more heterocycles. [4] The resist underlayer film-forming composition according to [3] above, wherein the unit structure of (i) or (ii) is a unit structure having an aromatic ring having at least one oxygen-containing substituent, or an aromatic ring connected by at least one -NH-. [5] The resist underlayer film-forming composition according to any one of [2] to [4] above, wherein the aromatic ring-containing polymer is a novolak resin having a unit structure comprising: (i) one or more unit structures having an aromatic ring which may have a substituent; and (ii) a 4- to 17-membered monocyclic, bicyclic, tricyclic, or tetracyclic organic group which may have a substituent, wherein the monocyclic ring is a non-aromatic monocyclic ring; and at least one of the monocyclic rings constituting the bicyclic, tricyclic, or tetracyclic ring is a non-aromatic monocyclic ring, and the remaining monocyclic rings may be either aromatic or non-aromatic monocyclic organic groups, wherein the monocyclic, bicyclic, tricyclic, or tetracyclic organic group may further form a fused ring with one or more aromatic rings to form a pentacyclic or larger ring, and wherein at least a carbon atom on the non-aromatic monocyclic ring of (ii) and a carbon atom on the aromatic ring of (i) are covalently bonded to each other, thereby bonding (i) and (ii). [6] The aromatic ring-containing polymer is a novolak resin having a unit structure represented by the following formula (AB): in formula (I), n represents the number of composite unit structures A-B, unit structure A is one or more unit structures having an aromatic ring which may have a substituent, and the substituent may contain a heteroatom, the unit structure contains a plurality of aromatic rings, and the plurality of aromatic rings are connected to each other by a linking group which may contain a heteroatom, the aromatic ring may be a heteroaromatic ring, or may be an aromatic ring which forms a fused ring with one or more heterocycles, and unit structure B represents one or more unit structures containing a structure represented by the following formula (B1), (B2) or (B3): [In formula (B1), R and R′ each independently represent a hydrogen atom, an aromatic ring residue having 6 to 30 carbon atoms which may have a substituent, a heterocyclic ring residue having 3 to 30 carbon atoms which may have a substituent, or a linear, branched, or cyclic alkyl group having 10 or less carbon atoms which may have a substituent.] [In formula (B2), Z ０ represents an aromatic ring residue or an aliphatic ring residue having 6 to 30 carbon atoms, which may have a substituent, or an organic group in which two aromatic ring residues or aliphatic ring residues are linked by a single bond; J １ and J ２ each independently represents a direct bond or a divalent organic group which may have a substituent. [In formula (B3), Z represents a monocyclic, bicyclic, tricyclic, or tetracyclic fused ring having 4 to 25 carbon atoms, which may have a substituent, and the monocyclic ring is a non-aromatic monocyclic ring; at least one of the monocyclic rings constituting the bicyclic, tricyclic, or tetracyclic ring is a non-aromatic monocyclic ring, and the remaining monocyclic rings may be aromatic or non-aromatic monocyclic rings; the monocyclic, bicyclic, tricyclic, or tetracyclic fused ring may further form a fused ring with one or more aromatic rings to form a pentacyclic or higher fused ring; X and Y are the same or different and each represent -CR 31 R 32 represents a - group, and R 31 and R 32 are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms; x and y represent the number of X and Y, respectively, and each independently represents 0 or 1; is bonded to any carbon atom (referred to as "carbon atom 1") constituting the non-aromatic monocyclic ring of Z (when x = 1) or extends from carbon atom 1 (when x = 0), is bonded to any of the carbon atoms (referred to as "carbon atom 2") constituting the non-aromatic monocycle of Z (when y = 1) or extends from carbon atom 2 (when y = 0), and carbon atom 1 and carbon atom 2 may be the same or different, and when different, they may belong to the same non-aromatic monocycle or different non-aromatic monocycles, and * indicates a bond.] [7] The formula (B3) is the following formula (B31): [in formula (B31), Z represents a 4- to 17-membered monocyclic, bicyclic, tricyclic, or tetracyclic organic group which may have a substituent, and the monocyclic group is a non-aromatic monocyclic group; at least one of the monocyclic groups constituting the bicyclic, tricyclic, or tetracyclic group is a non-aromatic monocyclic group, and the remaining monocyclic groups may be either aromatic or non-aromatic monocyclic groups; the monocyclic, bicyclic, tricyclic, or tetracyclic organic group may further form a condensed ring with one or more aromatic rings to form a pentacyclic or higher ring; C and C' each represent a carbon atom in the atomic group constituting the cyclic moiety of any of the non-aromatic monocyclic groups represented by Z, and the non-aromatic monocyclic groups to which C and C' belong may be the same or different; n represents the number of carbon atoms C' and represents an integer of 0 to 2; p, q, p', and q' represent the number of bonds and each independently represent 0 or 1; when n is 0, p and q are 1; When n is 1 or 2, at least one of p and q, and at least one of p' and q' of each C' are each 1; when n is 2, the non-aromatic monocycles to which the two C's belong may be the same or different, and when the two C's are the same, they may or may not be directly bonded; X, Y, X', and Y' may be the same or different, and each of them is -CR 1 R 2 represents a - group, and R 1 and R 2are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and when n is 2, two X' may be the same or different, two Y' may be the same or different, and x, y, x', and y' represent the numbers of X, Y, X', and Y', respectively, and each independently represent 0 or 1. [8] The resist underlayer film forming composition according to the above item [6], wherein the sulfonate anion group (SO ) contained in the thermal acid generator (a) is ３ － When the amount of base required to neutralize the same number of moles of sulfonic acid (monobasic acid) as that of the component (a) in formula (I) is taken as 1 equivalent, １ and the base B of component (c) ２ [9] The resist underlayer film forming composition according to any one of [1] to [7] above, wherein a base having a pKa greater than that of pyridine is present in an amount of 1.05 equivalents or more. ３ － When the amount of base required to neutralize the same number of moles of sulfonic acid (monobasic acid) as the base B is taken as 1 equivalent, ２

[10] The resist underlayer film-forming composition according to any one of the above items [1] to [7], wherein the amount of the counter base B in formula (1) of the component (a) is 0.05 to 3.0 equivalents. １ and / or the base B of component (c) ２ is R I R II R III N and R I and R II each independently represents a hydrogen atom or an optionally substituted linear or branched saturated or unsaturated aliphatic hydrocarbon group; R I and R II may form a ring via a heteroatom or without a heteroatom, or may form a ring via an aromatic ring; R III represents a hydrogen atom, an optionally substituted aromatic ring residue, or an optionally substituted linear or branched saturated or unsaturated aliphatic hydrocarbon group; R I and R II does not form a ring, R III

[11] The resist underlayer film-forming composition according to any one of the above [1] to [9], wherein the counter base B in formula (1) of the component (a) is a hydrogen atom or an optionally substituted aromatic ring residue. １ and / or the base B of component (c) ２ teeth, [In the formula, R １ and R ２ R each independently represents an optionally substituted linear or branched, saturated or unsaturated aliphatic hydrocarbon group; ３ represents a hydrogen atom or an optionally substituted aromatic hydrocarbon group, or a cyclic amine compound represented by the following formula (2): [In formula (II), R represents a hydrogen atom; an alkyl group having 1 to 10 carbon atoms, which may be substituted with a nitro group, a cyano group, an amino group, a carboxyl group, a hydroxy group, an amide group, an aldehyde group, a (meth)acryloyl group, a halogen atom, or an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, an organic group containing an ether bond, an organic group containing a ketone bond, or an organic group containing an ester bond; or a group comprising a combination thereof; R' represents an aromatic ring which forms a condensed ring with the ring of the cyclic amine in formula (II), or and R ａ and R ｂ each independently represents an optionally substituted alkylene group, X is O, S, SO ２ , CO, CONH, COO, or NH, and n and m are each independently 2, 3, 4, 5, or 6.

[12] The resist underlayer film-forming composition according to any one of the above items [1] to [9], wherein R in formula (II) is a base represented by the formula: ３ represents an optionally substituted phenyl, naphthyl, anthracenyl, pyrenyl or phenanthrenyl group, R in the above formula (3) is a hydrogen atom, a methyl group, an ethyl group, an isobutyl group, an allyl group or a cyanomethyl group, R' in the above formula (3) is

[13] The resist underlayer film forming composition according to the above

[11] , wherein n and m are each independently 2, 3, 4, 5, or 6.

[14] The counter base B in formula (1) of component (a) is １ and / or the base B of component (c) ２

[14] The resist underlayer film forming composition according to any one of the above items [1] to

[12] , wherein A in formula (1) is one or more of N-methylmorpholine, N-isobutylmorpholine, N-allylmorpholine, and N,N-diethylaniline. １is a methyl group, a trifluoromethyl group, a naphthyl group, a norbornanylmethyl group, a dimethylphenyl group, or a tolyl group.

[15] The resist underlayer film-forming composition according to any one of [1] to

[14] above, further comprising a crosslinking agent.

[16] The resist underlayer film-forming composition according to

[15] above, wherein the crosslinking agent is an aminoplast crosslinking agent or a phenoplast crosslinking agent.

[17] The resist underlayer film-forming composition according to

[16] above, wherein the aminoplast crosslinking agent is a highly alkylated, alkoxylated, or alkoxyalkylated melamine, benzoguanamine, glycoluril, urea, or a polymer thereof.

[18] The resist underlayer film-forming composition according to

[16] above, wherein the phenoplast crosslinking agent is a highly alkylated, alkoxylated, or alkoxyalkylated aromatic, or a polymer thereof.

[19] The resist underlayer film forming composition according to any one of [1] to

[18] above, wherein the solvent (d) is a compound having an alcoholic hydroxyl group or a compound having a group capable of forming an alcoholic hydroxyl group.

[20] The resist underlayer film forming composition according to

[19] above, wherein the compound having an alcoholic hydroxyl group or the compound having a group capable of forming an alcoholic hydroxyl group is a propylene glycol-based solvent, an oxyisobutyrate ester-based solvent, or a butylene glycol-based solvent.

[21] The resist underlayer film forming composition according to

[19] above, wherein the compound having an alcoholic hydroxyl group or the compound having a group capable of forming an alcoholic hydroxyl group is propylene glycol monomethyl ether, methyl 2-hydroxy-2-methylpropionate, cyclohexanone, propylene glycol monomethyl ether acetate, or ethyl lactate.

[22] The resist underlayer film forming composition according to any one of [1] to

[21] above, further comprising a surfactant.

[23] A resist underlayer film, which is a baked product of a coating film made of the resist underlayer film-forming composition according to any one of [1] to

[22] above, on a semiconductor substrate.

[24] A method for forming a resist pattern used in manufacturing a semiconductor, comprising the steps of applying the resist underlayer film-forming composition according to any one of [1] to

[22] above onto a semiconductor substrate and baking the composition to form a resist underlayer film.

[25] A method for manufacturing a semiconductor device, comprising the steps of: forming a resist underlayer film on a semiconductor substrate from the resist underlayer film-forming composition according to any one of [1] to

[22] above; forming a resist film thereon; forming a resist pattern by irradiating with light or an electron beam and developing the resist underlayer film; etching the resist underlayer film using the formed resist pattern; and processing a semiconductor substrate using the patterned resist underlayer film.

[26] A method for manufacturing a semiconductor device, comprising: a step of forming a resist underlayer film on a semiconductor substrate from the resist underlayer film-forming composition according to any one of [1] to

[22] above; a step of forming a hard mask thereon; a step of further forming a resist film thereon; a step of forming a resist pattern by irradiating with light or an electron beam and developing; a step of etching the hard mask using the formed resist pattern; a step of etching the resist underlayer film using the patterned hard mask; and a step of processing a semiconductor substrate using the patterned resist underlayer film.

[27] A method for manufacturing a semiconductor device, comprising: a step of forming a resist underlayer film on a semiconductor substrate from the resist underlayer film-forming composition according to any one of [1] to

[22] above; a step of forming a hard mask thereon; a step of further forming a resist film thereon; a step of forming a resist pattern by irradiating with light or an electron beam and developing; a step of etching the hard mask using the formed resist pattern; a step of etching the resist underlayer film using the patterned hard mask; a step of removing the hard mask; and a step of processing a semiconductor substrate using the patterned resist underlayer film.

[28] A method for manufacturing a semiconductor device, comprising the steps of: forming a resist underlayer film on a semiconductor substrate from the resist underlayer film-forming composition according to any one of [1] to

[22] above; forming a hard mask thereon; further forming a resist film thereon; forming a resist pattern by irradiating with light or an electron beam and developing; etching the hard mask using the formed resist pattern; etching the resist underlayer film using the patterned hard mask; removing the hard mask; and forming a vapor-deposited film (spacer) on the resist underlayer film after hard mask removal; processing the vapor-deposited film (spacer) by etching; removing the patterned resist underlayer film to leave the patterned vapor-deposited film (spacer); and processing the semiconductor substrate through the patterned vapor-deposited film (spacer).

[29] The manufacturing method according to any one of

[26] to

[28] above, wherein the hard mask is formed by coating or vapor-depositing an inorganic material.

[30] The manufacturing method of any one of

[25] to

[28] above, wherein the resist film is patterned by a nanoimprint method or a self-assembled film.

[31] The manufacturing method of a semiconductor device of

[27] or

[28] above, wherein the hard mask is removed by etching or an alkaline chemical solution.

[0006] According to the underlayer film-forming composition of the present invention, one or more bases B, which are additional base components, are ２ This allows the base to trap the acid generated during firing, slowing down the hardening rate, and as a result, SiO ２ A cured film with high planarization and high embedding properties can be obtained with various film types, such as TiN, SiN, etc. Furthermore, since there is no influence from the acid generator and the storage stability of the polymer, which is the main component of the resist underlayer film, can be ensured, a film can be formed that does not develop coloration and does not dissolve in photoresist solvents. In addition, the present invention provides a resist underlayer film obtained from the resist underlayer film-forming composition and a method for manufacturing a semiconductor device using the composition.

[0007] [I. Definitions of Terms] In this specification, definitions of main terms related to the novolac resin, which is one embodiment of the present invention, are explained below. Unless otherwise specified, the following definitions of each term apply to the novolac resin.

[0008] (I-1) "Novolac Resin" The term "novolac resin" is used in a broad sense to encompass not only phenol-formaldehyde resins (so-called novolac phenolic resins) and aniline-formaldehyde resins (so-called novolac aniline resins) in the narrow sense, but also polymers formed generally in the presence of an acid catalyst or under reaction conditions equivalent thereto by forming a covalent bond (substitution reaction, addition reaction, condensation reaction, addition-condensation reaction, or the like) between an organic compound having a functional group capable of forming a covalent bond with an aromatic ring [for example, an aldehyde group, a ketone group, an acetal group, a ketal group, a hydroxyl group or an alkoxy group bonded to a secondary or tertiary carbon, a hydroxyl group, an alkoxy group or a halo group bonded to the α-carbon atom (e.g., the benzylic carbon atom) of an alkylaryl group, or a carbon-carbon unsaturated bond such as in divinylbenzene or dicyclopentadiene] and an aromatic ring in a compound having an aromatic ring (preferably having a heteroatom-containing substituent such as an oxygen atom, a nitrogen atom or a sulfur atom on the aromatic ring).

[0009] Therefore, the novolac resin referred to in this specification is a polymer formed by linking compounds having a plurality of aromatic rings together, with an organic compound containing a carbon atom derived from the functional group (sometimes referred to as a "linking carbon atom") forming a covalent bond with an aromatic ring in a compound having an aromatic ring via the linking carbon atom.

[0010] In this specification, the terms unit structure A, unit structure B, and unit structure C are used as unit structures constituting a "novolac resin." Unit structure A is a unit structure derived from a compound having an aromatic ring. Unit structure B is a unit structure derived from a compound having a functional group that enables covalent bonding with the aromatic ring of unit structure A. Unit structure C is a unit structure equivalent in bonding mode to composite unit structure A-B, and is a unit structure derived from a compound having an aromatic ring and a functional group that enables covalent bonding with the aromatic ring of unit structure A. Because the bonding modes are the same, unit structure C can be replaced with composite unit structure A-B.

[0011] (I-2) "Residue" A "residue" refers to an organic group in which a hydrogen atom bonded to a carbon atom or a heteroatom (such as a nitrogen atom, oxygen atom, or sulfur atom) is replaced with a bonding hand, and may be a monovalent or polyvalent group. For example, replacing one hydrogen atom with one bonding hand results in a monovalent organic group, and replacing two hydrogen atoms with bonding hands results in a divalent organic group.

[0012] (I-3) "Aromatic Ring" (Aromatic Group, Aryl Group, Arylene Group) The term "aromatic ring" is a concept that encompasses aromatic hydrocarbon rings, aromatic heterocycles, and residues thereof [sometimes referred to as "aromatic groups," "aryl groups" (in the case of monovalent groups), or "arylene groups" (in the case of divalent groups)], and encompasses not only monocyclic (aromatic monocycles) but also polycyclic (aromatic polycycles). In the case of polycyclic rings, at least one monocycle is an aromatic monocycle, but the remaining monocycles that form a fused ring with the aromatic monocycle may be monocyclic heterocycles (heteromonocycles) or monocyclic alicyclic hydrocarbons (alicyclic monocycles).

[0013] Examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, indene, naphthalene, azulene, styrene, toluene, xylene, mesitylene, cumene, anthracene, phenanthrene, triphenylene, benzanthracene, pyrene, chrysene, fluorene, biphenyl, corannulene, perylene, fluoranthene, benzo[k]fluoranthene, benzo[b]fluoranthene, benzo[ghi]perylene, coronene, dibenzo[g,p]chrysene, acenaphthylene, acenaphthene, naphthacene, pentacene, and cyclooctatetraene, and more typically aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and pyrene; and aromatic hydrocarbon rings such as furan, pyran, pyridine, pyrimidine, pyrazine, thiophene, and pyrene. aromatic heterocycles such as pyrrole, N-alkylpyrrole, N-arylpyrrole, imidazole, pyridine, pyrimidine, pyrazine, triazine, thiazole, indole, phenylindole, bisindolefluorene, bisindolebenzofluorene, bisindoledibenzofluorene, purine, quinoline, isoquinoline, chromene, thianthrene, phenothiazine, phenoxazine, xanthene, acridine, phenazine, carbazole, and indolocarbazole; more typically, furan, thiophene, pyrrole, indole, phenylindole, bisindolefluorene, phenothiazine, carbazole, and indolocarbazole are included, but are not limited to these.

[0014] The aromatic ring (for example, a benzene ring, a naphthalene ring, etc.) may have an optional substituent, and such substituents include a halogen atom, a saturated or unsaturated linear, branched, or cyclic hydrocarbon group (-R) (the hydrocarbon chain may be interrupted one or more times by an oxygen atom, and includes an alkyl group, an alkenyl group, an alkynyl group, a propargyl group, etc.), an alkoxy group or an aryloxy group (-OR, where R represents the hydrocarbon group -R), an alkylamino group [-NHR or -NR ２(Two R's may be the same or different), where R's represent the hydrocarbon group -R, and include alkyl groups, alkenyl groups, alkynyl groups, propargyl groups, etc., whose hydrocarbon chains may be interrupted one or more times by oxygen atoms.], hydroxyl groups, amino groups (-NH ２ ), carboxyl group, cyano group, nitro group, ester group (-CO ２ R or -OCOR, where R represents the hydrocarbon group -R), an amide group (-NHCOR, -CONHR, -NRCOR (two Rs may be the same or different), or -CONR ２ (two R's may be the same or different), where R's represent the hydrocarbon group -R), a sulfonyl-containing group (-SO ２ R, where R represents the hydrocarbon group -R or a hydroxyl group -OH), a thiol group (-SH), a sulfide-containing group (-SR, where R represents the hydrocarbon group -R); an organic group containing an ether bond [R １１ -O-R １１ (R １１ each independently represents an alkyl group having 1 to 6 carbon atoms, such as a methyl group or an ethyl group, or an aryl group, such as a phenyl group, a naphthyl group, an anthranyl group or a pyrenyl group. Examples of substituents include residues of ether compounds represented by the formula (I); organic groups containing an ether bond, such as a methoxy group, an ethoxy group or a phenoxy group; and aryl groups.

[0015] Furthermore, organic groups having one or more condensed rings of aromatic rings (such as benzene, naphthalene, anthracene, and pyrene) with one or more aliphatic or heterocyclic rings are also included. Examples of the aliphatic rings include cyclobutane, cyclobutene, cyclopentane, cyclopentene, cyclohexane, cyclohexene, methylcyclohexane, methylcyclohexene, cycloheptane, and cycloheptene, and examples of the heterocyclic rings include furan, thiophene, pyrrole, imidazole, pyran, pyridine, pyrimidine, pyrazine, pyrrolidine, piperidine, piperazine, and morpholine.

[0016] It may also be an organic group having a structure in which two or more aromatic rings are linked by a divalent linking group such as an alkylene group.

[0017] (I-4) "Heterocycle" The term "heterocycle" encompasses both aliphatic heterocycles and aromatic heterocycles, and is a concept that encompasses not only monocyclic (heteromonocyclic) but also polycyclic (heteropolycyclic). In the case of a polycyclic, at least one monocyclic ring is a heteromonocyclic ring, but the remaining monocyclic rings may be aromatic hydrocarbon monocyclic or alicyclic monocyclic. For the aromatic heterocycle, the examples in (I-3) above can be referred to. As with the aromatic ring in (I-3) above, it may have a substituent.

[0018] (I-5) "Non-aromatic ring" (aliphatic ring) A "non-aromatic monocycle" refers to a monocyclic hydrocarbon that does not belong to the aromatic group, and is typically a monocycle of an alicyclic compound. It may also be called an aliphatic monocycle (which may include an aliphatic heteromonocycle, or may contain an unsaturated bond as long as it does not belong to the aromatic compound). As with the aromatic ring of (I-3) above, it may have a substituent.

[0019] Examples of non-aromatic monocyclic rings (aliphatic rings, aliphatic monocyclic rings) include cyclopropane, cyclobutane, cyclobutene, cyclopentane, cyclopentene, cyclohexane, methylcyclohexane, cyclohexene, methylcyclohexene, cycloheptane, and cycloheptene.

[0020] "Non-aromatic polycyclic rings" refer to polycyclic hydrocarbons that are not aromatic, and are typically polycyclic alicyclic compounds. They may also be called aliphatic polycyclic rings (which may include aliphatic heterocyclic rings (where at least one of the monocyclic rings constituting the polycyclic ring is an aliphatic heterocyclic ring), or may contain unsaturated bonds as long as they do not belong to the aromatic compound category). They include non-aromatic bicyclic rings, non-aromatic tricyclic rings, and non-aromatic tetracyclic rings.

[0021] "Non-aromatic bicycle" refers to a fused ring composed of two monocyclic hydrocarbons that are not aromatic, typically two fused rings of an alicyclic compound. In this specification, it is also referred to as an aliphatic bicycle (which may include an aliphatic heterobicycle, and may contain unsaturated bonds as long as it does not belong to the aromatic compound). Examples of non-aromatic bicycles include bicyclopentane, bicyclooctane, and bicycloheptene.

[0022] A "non-aromatic tricyclic ring" refers to a fused ring composed of three monocyclic hydrocarbons that are not aromatic, and is typically a fused ring of three alicyclic compounds (each of which may be a heterocyclic ring or may contain an unsaturated bond as long as it is not an aromatic compound). Examples of non-aromatic tricyclic rings include tricyclooctane, tricyclononane, and tricyclodecane.

[0023] The term "non-aromatic tetracyclic ring" refers to a fused ring composed of four monocyclic hydrocarbons that are not aromatic, and is typically a fused ring of four alicyclic compounds (each of which may be a heterocyclic ring or may contain an unsaturated bond as long as it is not an aromatic compound). Examples of non-aromatic tetracyclic rings include hexadecahydropyrene.

[0024] (I-6) The term "carbon atoms constituting a ring (moiety)" refers to the carbon atoms constituting a hydrocarbon ring (which may be an aromatic ring, an aliphatic ring, or a heterocyclic ring) in an unsubstituted state.

[0025] (I-7) The term "hydrocarbon group" refers to a group formed by removing one or more hydrogen atoms from a hydrocarbon, and such hydrocarbons include saturated or unsaturated aliphatic hydrocarbons, saturated or unsaturated alicyclic hydrocarbons, and aromatic hydrocarbons.

[0026] (I-8) In the chemical structural formula showing the unit structure of the novolak resin in this specification, a bond (indicated by *) may be shown for convenience. However, unless otherwise specified, such a bond may be at any available bonding position in the unit structure, and does not in any way limit the bonding position in the unit structure.

[0027] [II. Thermal Acid Generator] (II-1) The thermal acid generator, which is the component (a) in the resist underlayer film-forming composition of one embodiment of the present invention, is represented by the following formula (1). Here, in formula (1), A １is an optionally substituted linear, branched, or cyclic saturated or unsaturated aliphatic hydrocarbon group, or an optionally substituted aromatic ring residue, preferably a methyl group, a trifluoromethyl group, a naphthyl group, a norbornanylmethyl group, a dimethylphenyl group, or a tolyl group. Here, the term "aromatic ring" encompasses an aromatic hydrocarbon ring and an aromatic heterocycle, and the term "residue" refers to an organic group in which a hydrogen atom bonded to a carbon atom or a heteroatom (nitrogen atom, oxygen atom) is replaced with a bond, and may be a monovalent group or a polyvalent group. In formula (1), n ​​represents the number of sulfonate anion groups, and is 1 or 2, preferably 1. In formula (1), B １ is one or more counter bases, and is a mono-acid base or represents the mono-acid base portion of a di-acid base or tri-acid base. １ When is a diacid or triacid, B １ There are two or three equivalents to A, which are covalently bonded to each other. １ and B １ The pair base B may be linked to the pair base B via a single bond or a linking group. １ and the base B of component (c) described below. ２ Among them, at least one base has a pKa greater than that of pyridine. １ and component (c) base B ２ The equivalent ratio and the like will be explained later in (IV-2) to (IV-3).

[0028] (II-2) Preferably, the counter base B in the formula (I) of component (a) １ and / or the base B of component (c) ２ is R I R II R III N. [Wherein, R I and R II each independently represents a hydrogen atom or an optionally substituted linear or branched saturated or unsaturated aliphatic hydrocarbon group; R I and R IImay form a ring via a heteroatom or without a heteroatom, or may form a ring via an aromatic ring, and the heteroatom is preferably an oxygen atom, a nitrogen atom, or a sulfur atom; R III represents a hydrogen atom, an optionally substituted aromatic ring residue, or an optionally substituted linear or branched saturated or unsaturated aliphatic hydrocarbon group; R I and R II does not form a ring, R III is a hydrogen atom or an aromatic ring residue which may be substituted. More preferably, the counter base B in formula (1) of component (a) is １ and / or the base B of component (c) ２ teeth, [In the formula, R １ and R ２ R each independently represents an optionally substituted linear or branched, saturated or unsaturated aliphatic hydrocarbon group; ３ represents a hydrogen atom or an optionally substituted aromatic group, preferably an optionally substituted phenyl, naphthyl, anthracenyl, pyrenyl, or phenanthrenyl group, or a cyclic amine compound of the following formula (III): [In formula (3), R represents a hydrogen atom; an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, an organic group containing an ether bond, an organic group containing a ketone bond, or an organic group containing an ester bond, which may be substituted with a nitro group, a cyano group, an amino group, a carboxyl group, a hydroxyl group, an amide group, an aldehyde group, a (meth)acryloyl group, a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), or an alkoxy group having 1 to 10 carbon atoms; an organic group containing an ether bond, an organic group containing a ketone bond, or an organic group containing an ester bond; or a group comprising a combination thereof; R' represents an aromatic ring which forms a condensed ring with the ring of the cyclic amine in formula (3), or and R ａ and R ｂ each independently represents an optionally substituted alkylene group, X represents O, S, SO ２, CO, CONH, COO, or NH, and n and m are each independently 2, 3, 4, 5, or 6. Preferably, R in formula (3) is a hydrogen atom, a methyl group, an ethyl group, an isobutyl group, an allyl group, or a cyanomethyl group. Also preferably, R' in formula (3) is wherein n and m are each independently 2, 3, 4, 5, or 6.

[0029] (II-3) (II-3-1) A in formula (1) １ In the definition of R I R II R III R in N I , R II , R III In the definition of R １ R ２ R ３ R in N １ , R ２ Examples of the "straight-chain, branched, saturated aliphatic hydrocarbon group" in the definition of (1) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, an s-butyl group, a t-butyl group, an n-pentyl group, a 1-methyl-n-butyl group, a 2-methyl-n-butyl group, a 3-methyl-n-butyl group, a 1,1-dimethyl-n-propyl group, a 1,2-dimethyl-n-propyl group, a 2,2-dimethyl-n-propyl group, a 1-ethyl-n-propyl group, an n-hexyl group, a 1-methyl-n-pentyl group, a 2-methyl-n-pentyl group, Examples include a 3-methyl-n-pentyl group, a 4-methyl-n-pentyl group, a 1,1-dimethyl-n-butyl group, a 1,2-dimethyl-n-butyl group, a 1,3-dimethyl-n-butyl group, a 2,2-dimethyl-n-butyl group, a 2,3-dimethyl-n-butyl group, a 3,3-dimethyl-n-butyl group, a 1-ethyl-n-butyl group, a 2-ethyl-n-butyl group, a 1,1,2-trimethyl-n-propyl group, a 1,2,2-trimethyl-n-propyl group, a 1-ethyl-1-methyl-n-propyl group, and a 1-ethyl-2-methyl-n-propyl group.

[0030] (II-3-2) A of formula (1) １In the definition of the formula (I), examples of the "cyclic saturated aliphatic hydrocarbon group" include a cyclopropyl group, a cyclobutyl group, a 1-methylcyclopropyl group, a 2-methylcyclopropyl group, a cyclopentyl group, a 1-methylcyclobutyl group, a 2-methylcyclobutyl group, a 3-methylcyclobutyl group, a 1,2-dimethylcyclopropyl group, a 2,3-dimethylcyclopropyl group, a 1-ethylcyclopropyl group, a 2-ethylcyclopropyl group, a cyclohexyl group, a 1-methylcyclopentyl group, a 2-methylcyclopentyl group, a 3-methylcyclopentyl group, a 1-ethylcyclobutyl group, a 2-ethylcyclobutyl group, a 3-ethylcyclobutyl group, a 1,2-dimethylcyclobutyl group, a 1 , 3-dimethyl-cyclobutyl group, 2,2-dimethyl-cyclobutyl group, 2,3-dimethyl-cyclobutyl group, 2,4-dimethyl-cyclobutyl group, 3,3-dimethyl-cyclobutyl group, 1-n-propyl-cyclopropyl group, 2-n-propyl-cyclopropyl group, 1-i-propyl-cyclopropyl group, 2-i-propyl-cyclopropyl group, 1,2,2-trimethyl-cyclopropyl group, 1,2,3-trimethyl-cyclopropyl group, 2,2,3-trimethyl-cyclopropyl group, 1-ethyl-2-methyl-cyclopropyl group, 2-ethyl-1-methyl-cyclopropyl group, 2-ethyl-2-methyl-cyclopropyl group, and 2-ethyl-3-methyl-cyclopropyl group.

[0031] (II-3-3) A of formula (1) １ In the definition of R I R II R III R in N I , R II , R III In the definition of R １ R ２ R ３ R in N １ , R ２Examples of the "straight-chain, branched, unsaturated aliphatic hydrocarbon group" in the definition of (1) include ethenyl group, 1-propenyl group, 2-propenyl group, 1-methyl-1-ethenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, 2-methyl-1-propenyl group, 2-methyl-2-propenyl group, 1-ethylethenyl group, 1-methyl-1-propenyl group, 1-methyl-2-propenyl group, 1-pentenyl group, 2-pentenyl group, 3-pentenyl group, 4-pentenyl group, 1-n-propylethenyl group, 1-methyl-1-butenyl group, 1-methyl-2-butenyl group, 1-methyl-3-butenyl group, 2-ethyl-2-propenyl group, 2-methyl-1-butenyl group, 2-methyl-2-butenyl group, 2-methyl-3-butenyl group, 3-methyl-1-butenyl group, 3-methyl-2-butenyl group, 3-methyl-3-butenyl group, 1,1-dimethyl-2-propenyl group, 1-i-propylethenyl group, 1,2-dimethyl-1-propenyl group, 1,2-dimethyl-2-propenyl group, 1-hexenyl group, 2-hexenyl group, 3-hexenyl group, 4-hexenyl group, 5-hexenyl group, 1-methyl-1-pentenyl group, 1-methyl-2- pentenyl group, 1-methyl-3-pentenyl group, 1-methyl-4-pentenyl group, 1-n-butylethenyl group, 2-methyl-1-pentenyl group, 2-methyl-2-pentenyl group, 2-methyl-3-pentenyl group, 2-methyl-4-pentenyl group, 2-n-propyl-2-propenyl group, 3-methyl-1-pentenyl group, 3-methyl-2-pentenyl group, 3-methyl-3-pentenyl group, 3-methyl-4-pentenyl group, 3-ethyl-3-butenyl group, 4-methyl-1-pentenyl group, 4-methyl-2-pentenyl group, 4-methyl-3-pentenyl group, 4- Methyl-4-pentenyl group, 1,1-dimethyl-2-butenyl group, 1,1-dimethyl-3-butenyl group, 1,2-dimethyl-1-butenyl group, 1,2-dimethyl-2-butenyl group, 1,2-dimethyl-3-butenyl group, 1-methyl-2-ethyl-2-propenyl group, 1-s-butylethenyl group, 1,3-dimethyl-1-butenyl group, 1,3-dimethyl-2-butenyl group, 1,3-dimethyl-3-butenyl group, 1-i-butylethenyl group, 2,2-dimethyl-3-butenyl group, 2,3-dimethyl-1-butenyl group, 2,3-dimethyl-2-butenyl group,Examples of such alkyl groups include a 3-dimethyl-3-butenyl group, a 2-i-propyl-2-propenyl group, a 3,3-dimethyl-1-butenyl group, a 1-ethyl-1-butenyl group, a 1-ethyl-2-butenyl group, a 1-ethyl-3-butenyl group, a 1-n-propyl-1-propenyl group, a 1-n-propyl-2-propenyl group, a 2-ethyl-1-butenyl group, a 2-ethyl-2-butenyl group, a 2-ethyl-3-butenyl group, a 1,1,2-trimethyl-2-propenyl group, a 1-t-butylethenyl group, a 1-methyl-1-ethyl-2-propenyl group, a 1-ethyl-2-methyl-1-propenyl group, a 1-ethyl-2-methyl-2-propenyl group, a 1-i-propyl-1-propenyl group, and a 1-i-propyl-2-propenyl group.

[0032] (II-3-4) A of formula (1) １ In the definition of the above, examples of the "cyclic unsaturated aliphatic hydrocarbon group" include a 1-cyclopentenyl group, a 2-cyclopentenyl group, a 3-cyclopentenyl group, a 1-methyl-2-cyclopentenyl group, a 1-methyl-3-cyclopentenyl group, a 2-methyl-1-cyclopentenyl group, a 2-methyl-2-cyclopentenyl group, a 2-methyl-3-cyclopentenyl group, a 2-methyl-4-cyclopentenyl group, a 2-methyl-5-cyclopentenyl group, a 2-methylene-cyclopentyl group, a 3-methyl-1-cyclopentenyl group, a 3-methyl-2-cyclopentenyl group, a 3-methyl-3-cyclopentenyl group, a 3-methyl-4-cyclopentenyl group, a 3-methyl-5-cyclopentenyl group, a 3-methylene-cyclopentyl group, a 1-cyclohexenyl group, a 2-cyclohexenyl group, and a 3-cyclohexenyl group.

[0033] (II-3-5) A of formula (1) １In the definition of R in formula (3), or in the definition of R in formula (3), examples of the aromatic hydrocarbon group include a phenyl group, an o-methylphenyl group, an m-methylphenyl group, a p-methylphenyl group, a 2,3-dimethylphenyl group, a 2,4-dimethylphenyl group, a 2,5-dimethylphenyl group, a 2,6-dimethylphenyl group, a 3,4-dimethylphenyl group, a 3,5-dimethylphenyl group, an o-chlorophenyl group, an m-chlorophenyl group, a p-chlorophenyl group, an o-fluorophenyl group, Examples of the alkyl group include a phenyl group, a p-fluorophenyl group, an o-methoxyphenyl group, a p-methoxyphenyl group, a p-nitrophenyl group, a p-cyanophenyl group, an α-naphthyl group, a β-naphthyl group, an o-biphenylyl group, an m-biphenylyl group, a p-biphenylyl group, a 1-anthryl group, a 2-anthryl group, a 9-anthryl group, a 1-phenanthryl group, a 2-phenanthryl group, a 3-phenanthryl group, a 4-phenanthryl group, a 9-phenanthryl group, a 1-pyrenyl group, a 2-pyrenyl group, and a 3-pyrenyl group. １ In the definition of R, examples of the aromatic heterocyclic residue of the "aromatic ring residue" include a furanyl group, a thiophenyl group, a pyrrolyl group, an imidazolyl group, a pyranyl group, a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyrrolidinyl group, a piperidinyl group, a piperazinyl group, a morpholinyl group, a quinuclidinyl group, an indolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a chromenyl group, a thianthrenyl group, a phenothiazinyl group, a phenoxazinyl group, a xanthenyl group, an acridinyl group, a phenazinyl group, and a carbazolyl group. I R II R III R in N III In the definition of R １ R ２ R ３ R in N ３ The "aromatic ring" or "aromatic ring" in the definition of the above is the same as exemplified above.

[0034] (II-3-6) A of formula (1) １ In the definition of R I R II R III R in N I , RII , R III In the definition of R １ R ２ R ３ R in N １ , R ２ , R ３ In the definition of R ａ , R ｂ In the definition of (II-3-9), examples of the substituent corresponding to "optionally substituted" include a nitro group, an amino group, a cyano group, a sulfo group, a hydroxy group, a carboxyl group, an aldehyde group, a propargylamino group, a propargyloxy group, a halogen atom, an alkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, an organic group containing an ether bond, an organic group containing a ketone bond, an organic group containing an ester bond, or a combination thereof. For the organic group containing an ether bond, the organic group containing a ketone bond, and the organic group containing an ester bond, see the examples in (II-3-9) below.

[0035] (II-3-7) Examples of the "alkoxy group" in the definition of R in formula (3) include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, an s-butoxy group, a t-butoxy group, an n-pentyloxy group, a 1-methyl-n-butoxy group, a 2-methyl-n-butoxy group, a 3-methyl-n-butoxy group, a 1,1-dimethyl-n-propoxy group, a 1,2-dimethyl-n-propoxy group, a 2,2-dimethyl-n-propoxy group, a 1-ethyl-n-propoxy group, an n-hexyloxy group, a 1-methyl-n-pentyloxy group, and a 2-methyl-n-pentyloxy group. , 3-methyl-n-pentyloxy group, 4-methyl-n-pentyloxy group, 1,1-dimethyl-n-butoxy group, 1,2-dimethyl-n-butoxy group, 1,3-dimethyl-n-butoxy group, 2,2-dimethyl-n-butoxy group, 2,3-dimethyl-n-butoxy group, 3,3-dimethyl-n-butoxy group, 1-ethyl-n-butoxy group, 2-ethyl-n-butoxy group, 1,1,2-trimethyl-n-propoxy group, 1,2,2-trimethyl-n-propoxy group, 1-ethyl-1-methyl-n-propoxy group, and 1-ethyl-2-methyl-n-propoxy group.

[0036] (II-3-8) In the definition of R in formula (3), or R ａ , R ｂ The "alkylene group" in the definition of (III) can be exemplified by alkylene groups obtained by replacing a hydrogen atom of an alkyl group exemplified in (II-3-1) to (II-3-2) above with an additional bond. Furthermore, the "alkenyl group" in the definition of R in (III) can be referenced to the examples in (II-3-3) to (II-3-4) above. Furthermore, the "hydroxyalkyl group" in the definition of R in (III) can be exemplified by the following organic groups. In the formula, * represents the carbon atom to which the bond extends. Furthermore, the "alkynyl group" in the definition of R in formula (3) includes modes bonded to an aliphatic hydrocarbon chain (bonded to the end of the chain or inserted into the middle of the chain), modes further containing a heteroatom (oxygen atom, nitrogen atom, etc.), and modes in which multiple alkynyl groups are linked, and examples thereof include the following organic groups: * in the formula represents the carbon atom to which the bond extends.

[0037]

[0038] (II-3-9) The "organic group containing an ether bond" in the definition of R in formula (3) is R １１ -O-R １１ (R １１ are each independently an alkyl group having 1 to 6 carbon atoms, such as a methyl group or an ethyl group, an alkylene group, a phenyl group, a phenylene group, a naphthyl group, a naphthylene group, an anthranyl group, or a pyrenyl group. ) and examples thereof include organic groups containing an ether bond, such as a methoxy group, an ethoxy group, or a phenoxy group. The "organic group containing a ketone bond" in the definition of R in formula (3) is R ２１ -C(=O)-R ２１ (R ２１ are each independently an alkyl group having 1 to 6 carbon atoms, such as a methyl group or an ethyl group, an alkylene group, a phenyl group, a phenylene group, a naphthyl group, a naphthylene group, an anthranyl group, or a pyrenyl group. ) and examples thereof include organic groups containing a ketone bond, such as an acetoxy group or a benzoyl group. The "organic group containing an ester bond" in the definition of R in formula (3) can be a residue of a ketone compound represented by the formula (3), such as R ３１ -C(=O)O-R ３１ (R ３１ each independently represents an alkyl group having 1 to 6 carbon atoms, such as a methyl group or an ethyl group, an alkylene group, a phenyl group, a phenylene group, a naphthyl group, a naphthylene group, an anthranyl group, or a pyrenyl group.) Examples of such organic groups include organic groups containing an ester bond, such as methyl ester, ethyl ester, and phenyl ester.

[0039] (II-4) Examples of the thermal acid generator represented by formula (I) include, but are not limited to, any combination of at least one of the examples of counter base cations and at least one of the examples of sulfonate anions shown below, in such a way that the charge is neutral.

[0040] (II-4-1: Examples of counter base cations)

[0041] (II-4-2: Examples of sulfonate anions)

[0042] (II-4-3) More specifically, examples of thermal acid generators that are combinations of counter base cations and sulfonate anions include, but are not limited to, the following.

[0043] (II-5) The amount of the thermal acid generator is 0.0001 to 20% by mass, preferably 0.0005 to 10% by mass, and more preferably 0.01 to 3% by mass, based on the total solid content in the resist underlayer film-forming composition. The thermal decomposition initiation temperature, i.e., the thermal acid generation temperature, of the thermal acid generator according to one embodiment of the present invention is preferably 50°C or higher, more preferably 100°C or higher, and even more preferably 150°C or higher, and is preferably 400°C or lower.

[0044] [III. Polymers Containing Aromatic Rings] (III-1) The polymer containing an aromatic ring is not particularly limited, and may be, for example, at least one selected from the group consisting of polyvinyl alcohol, polyacrylamide, (meth)acrylic resins, polyamic acids, polyhydroxystyrenes, polyhydroxystyrene derivatives, copolymers of polymethacrylate and maleic anhydride, epoxy resins, phenolic resins, novolak resins, resol resins, maleimide resins, polyetheretherketone resins, polyetherketone resins, polyethersulfone resins, polyketone resins, polyester resins, polyether resins, urea resins, polyamides, polyimides, cellulose, cellulose derivatives, starch, chitin, chitosan, gelatin, zein, sugar-skeleton polymer compounds, polyethylene terephthalate, polycarbonates, polyurethanes, and polysiloxanes, each of which contains an aromatic ring. These resins may be used alone or in combination of two or more.

[0045] (III-2) (III-2-1) The polymer containing an aromatic ring is preferably a novolak resin. The term "novolak resin" as used herein has already been explained in (I-1) of [I. Definitions of Terms] above. (III-2-2) More preferably, the polymer containing an aromatic ring is a novolak resin containing a unit structure having an aromatic ring which may have a substituent, wherein the aromatic ring: (i) contains a heteroatom in the substituent on the aromatic ring, (ii) contains multiple aromatic rings in the unit structure, at least two of the aromatic rings are connected to each other by a linking group which contains a heteroatom, or (iii) the aromatic ring is an aromatic heterocycle, or an aromatic ring which forms a fused ring with one or more heterocycles. These aromatic rings (i) to (iii) correspond to the unit structure A in the novolak resin described in (I-1) above. For the aromatic ring, see the explanation of the aromatic ring in (I-3) above, and for the heterocycle, see the explanation of the heterocycle in (I-4) above. More preferably, the unit structure (i) or (ii) above is a unit structure having at least one, more preferably two, aromatic rings having an oxygen-containing substituent, or a plurality of aromatic rings connected by at least one -NH-. The oxygen-containing substituent includes a hydroxyl group; a hydroxyl group in which a hydrogen atom is replaced by a saturated or unsaturated linear, branched, or cyclic hydrocarbon group (i.e., an alkoxy group); and a saturated or unsaturated linear, branched, or cyclic hydrocarbon group interrupted one or more times by an oxygen atom, an aromatic ring residue, and the like.

[0046] (III-2-3) More preferably, the aromatic ring-containing polymer comprises: (i) one or more unit structures having an aromatic ring which may have a substituent; and (ii) a 4- to 12-membered monocyclic, bicyclic, tricyclic, or tetracyclic organic group unit structure which may have a substituent, wherein the monocyclic ring is a non-aromatic monocyclic ring; and at least one of the monocyclic rings constituting the bicyclic, tricyclic, or tetracyclic ring is a non-aromatic monocyclic ring, and the remaining monocyclic rings contain an organic group which may be either an aromatic monocyclic or a non-aromatic monocyclic ring. Such unit structures also include unit structures in which two or three of the same or different organic groups are linked by a divalent or trivalent linking group to form a dimer or trimer. Furthermore, the monocyclic, bicyclic, tricyclic, or tetracyclic organic group may further be fused with one or more aromatic rings to form a pentacyclic or higher ring. In the novolak resin, at least a carbon atom (linking carbon atom) on the non-aromatic monocycle of (ii) and a carbon atom on the aromatic ring of (i) are covalently bonded to bond (i) and (ii). That is, the unit structure of (i) corresponds to the unit structure A of the novolak resin described in (I-1) above, and the monocyclic, bicyclic, tricyclic, or tetracyclic organic group of (ii) corresponds to the unit structure B of the novolak resin described in (I-1) above. Typical examples of (ii) include a unit structure in which the keto group of a cyclic ketone is replaced with two bond proxies; and a unit structure in which the tertiary hydroxyl group of a compound obtained by adding an organic group to the keto group of a cyclic ketone to convert it into a tertiary alcohol is replaced with one bond proxies. When the unit structure (ii) contains an aromatic ring, and the aromatic ring is bonded to each of the linking carbon atoms of two other unit structures (ii), the unit structure (ii) can be used as a type of unit structure (i), i.e., as unit structure A. When the unit structure (ii) contains an aromatic ring X, and the linking carbon atom of the unit structure (ii) is bonded to the aromatic ring Y of one other unit structure (i) and the aromatic ring X of the unit structure (ii) is bonded to the linking carbon atom of one other unit structure (ii), the unit structure (ii) can be used as a unit structure equivalent to the composite unit structure by replacing at least a part of a composite unit structure consisting of one unit structure (i) and one unit structure (ii).This corresponds to the unit structure C in the novolak resin (I-1) above.

[0047] (III-3) Novolac resin containing a composite unit structure A-B The novolac resin is preferably a novolac resin represented by the following formula (AB): The compound includes a composite unit structure AB represented by:

[0048] In formula (AB), n represents the number of composite unit structures A-B. Unit structure A is one or more unit structures having an aromatic ring which may have a substituent. The substituent may contain a heteroatom; the unit structure may contain multiple aromatic rings, and the multiple aromatic rings may be connected to each other by a linking group which may contain a heteroatom; the aromatic ring may be a heteroaromatic ring, or may be an aromatic ring which forms a fused ring with one or more heterocycles. Furthermore, unit structure B is one or more unit structures which contain a linking carbon atom which bonds to an aromatic ring in unit structure A [see (I-1) "Novolak Resin" above], and includes a structure represented by formula (B1), (B2), or (B3), which will be described below in (III-3-B10) to (III-3-B14), (III-3-B20) to (III-3-B23), and (III-3-B30) to (III-3-B35), respectively. Such unit structures also include unit structures in which two or three identical or different structures represented by these formulas are linked by a divalent or trivalent linking group. Unit structure B can link two unit structures A by covalently bonding to a carbon atom on the aromatic ring of unit structure A. Furthermore, at least one composite unit structure A-B may be replaced with one or more unit structures C containing structures represented by formulas (C1), (C2), (C3), and (C4), which will be described below in (III-3-B13), (III-3-B22), and (III-3-B34), respectively, as an equivalent unit structure.

[0049] (III-3-A0) Unit Structure A The "aromatic ring" in unit structure A is a concept that encompasses not only aromatic hydrocarbon rings but also aromatic heterocycles, and not only monocyclic but also polycyclic rings. In the case of a polycyclic ring, at least one monocycle is an aromatic monocycle, but the remaining monocycles may be heterocyclic monocycles or alicyclic monocycles, as already explained in (I-3) above. For further details, the explanation of the aromatic ring in (I-3) above and the explanation of the heterocycle in (I-4) above can be referred to. The "aromatic ring" in unit structure A may also be an organic group having a structure in which two or more aromatic rings are linked by a linking group such as an alkylene group. Preferably, the "aromatic ring" in unit structure A has 6 to 30 or 6 to 24 carbon atoms. Preferably, the "aromatic ring" in unit structure A is one or more benzene rings, naphthalene rings, anthracene rings, or pyrene rings; or a condensed ring of a benzene ring, a naphthalene ring, an anthracene ring, or a pyrene ring with a heterocycle or an aliphatic ring. The aromatic ring in unit structure A may optionally have a substituent, but it is preferable that the substituent contains a heteroatom. Furthermore, the aromatic ring in unit structure A may have two or more aromatic rings linked by a linking group, and it is preferable that the linking group contains a heteroatom. Examples of heteroatoms include an oxygen atom, a nitrogen atom, a sulfur atom, and the like. Preferably, the "aromatic ring" in unit structure A is an organic group having 6 to 30 or 6 to 24 carbon atoms and containing at least one heteroatom selected from N, S, and O on the ring, within the ring, or between rings. Examples of heteroatoms contained on the ring include nitrogen atoms contained in amino groups (e.g., propargylamino groups) and cyano groups; oxygen atoms contained in oxygen-containing substituents such as formyl groups, hydroxy groups, carboxyl groups, and alkoxy groups (e.g., propargyloxy groups); and nitrogen and oxygen atoms contained in oxygen-containing and nitrogen-containing substituents such as nitro groups. Examples of heteroatoms contained in the ring include oxygen atoms contained in xanthene and nitrogen atoms contained in carbazole. Heteroatoms contained in the linking group of two or more aromatic rings include an -NH- bond, an -NHCO- bond, an -O- bond, a -COO- bond, a -CO- bond, an -S- bond, an -SS- bond, an -SO ２Examples of the unit structure A include a nitrogen atom, an oxygen atom, and a sulfur atom contained in the - bond. Preferably, the unit structure A is a unit structure having an aromatic ring having the above-mentioned oxygen-containing substituent, a unit structure having two or more aromatic rings connected by -NH-, or a unit structure having one or more fused rings of one or more aromatic hydrocarbon rings and one or more heterocyclic rings.

[0050] (III-3-A1) Preferably, the unit structure A is at least one selected from the following: (Examples of amine skeletons)

[0051] (Example of a phenol skeleton) Furthermore, the H of NH of the amine skeleton and the H of OH of the phenol skeleton may be substituted with the following substituents.

[0052] (III-3-A2) Preferably, the unit structure A is at least one selected from the following: (Examples of unit structures derived from heterocycles) (Examples of unit structures derived from aromatic hydrocarbons having oxygen-containing substituents) (Examples of unit structures derived from aromatic hydrocarbons linked by —NH—)

[0053] (III-3-B0) Unit Structure B Unit Structure B is one or more unit structures containing a linking carbon atom bonding to an aromatic ring in Unit Structure A [see (I-1) "Novolak Resin" above], and includes structures represented by formula (B1), (B2), or (B3), which will be described below in (III-3-B10) to (III-3-B14), (III-3-B20) to (III-3-B23), and (III-3-B30) to (III-3-B35), respectively.

[0054] (III-3-B10) Formula (B1) In formula (B1), R and R' each independently represent a hydrogen atom, an aromatic ring having 6 to 30 carbon atoms which may have a substituent, a heterocyclic ring having 3 to 30 carbon atoms which may have a substituent, or a linear, branched, or cyclic alkyl group which may have 10 or less carbon atoms which may have a substituent. In the definitions of R and R' in formula (B1), the terms "substituent," "aromatic ring," and "heterocyclic ring" are the same as those explained above in (I-3), (I-4), etc.

[0055] Furthermore, the two bonds in formula (B1) can be covalently bonded to the aromatic ring in the structural unit A.

[0056] (III-3-B11) In the definition of R and R′ in formula (B1), examples of the “alkyl group” include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a cyclopropyl group, an n-butyl group, an i-butyl group, an s-butyl group, a t-butyl group, a cyclobutyl group, a 1-methyl-cyclopropyl group, a 2-methyl-cyclopropyl group, an n-pentyl group, a 1-methyl-n-butyl group, a 2-methyl-n-butyl group, a 3-methyl-n-butyl group, a 1,1-dimethyl-n-propyl group, a 1,2-dimethyl-n-propyl group, a 2,2-dimethyl-n-propyl group, a 1- Ethyl-n-propyl group, cyclopentyl group, 1-methyl-cyclobutyl group, 2-methyl-cyclobutyl group, 3-methyl-cyclobutyl group, 1,2-dimethyl-cyclopropyl group, 2,3-dimethyl-cyclopropyl group, 1-ethyl-cyclopropyl group, 2-ethyl-cyclopropyl group, n-hexyl group, 1-methyl-n-pentyl group, 2-methyl-n-pentyl group, 3-methyl-n-pentyl group, 4-methyl-n-pentyl group, 1,1-dimethyl-n-butyl group, 1,2-dimethyl-n-butyl group, 1,3-dimethyl-n-butyl group ethyl group, 2,2-dimethyl-n-butyl group, 2,3-dimethyl-n-butyl group, 3,3-dimethyl-n-butyl group, 1-ethyl-n-butyl group, 2-ethyl-n-butyl group, 1,1,2-trimethyl-n-propyl group, 1,2,2-trimethyl-n-propyl group, 1-ethyl-1-methyl-n-propyl group, 1-ethyl-2-methyl-n-propyl group, cyclohexyl group, 1-methyl-cyclopentyl group, 2-methyl-cyclopentyl group, 3-methyl-cyclopentyl group, 1-ethyl-cyclobutyl group, 2-ethyl-cyclobutyl group cyclobutyl group, 3-ethylcyclobutyl group, 1,2-dimethylcyclobutyl group, 1,3-dimethylcyclobutyl group, 2,2-dimethylcyclobutyl group, 2,3-dimethylcyclobutyl group, 2,4-dimethylcyclobutyl group, 3,3-dimethylcyclobutyl group, 1-n-propylcyclopropyl group, 2-n-propylcyclopropyl group, 1-i-propylcyclopropyl group, 2-i-propylcyclopropyl group, 1,2,2-trimethylcyclopropyl group, 1,2,3-trimethylcyclopropyl group, 2,2,Examples include a 3-trimethyl-cyclopropyl group, a 1-ethyl-2-methyl-cyclopropyl group, a 2-ethyl-1-methyl-cyclopropyl group, a 2-ethyl-2-methyl-cyclopropyl group, and a 2-ethyl-3-methyl-cyclopropyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, and an n-decyl group.

[0057] Preferably, R and R' are each independently phenyl, naphthalenyl, anthracenyl, phenanthrenyl, naphthacenyl, or pyrenyl.

[0058] (III-3-B12) In principle, the two bonds in formula (B1) are bonded to aromatic rings of other structures (corresponding to unit structure A) having an aromatic ring, but at the polymer terminals, they are bonded to polymer terminal groups [see (III-3-B4) below]. Furthermore, the unit structure containing the structure represented by formula (B1) may contain, for example, a structure in which two or three identical or different structures of formula (B1) are bonded to a divalent or trivalent linking group to form a dimer or trimer structure. In this case, as shown in formula (B11) below, one of the two bonds in each structure of formula (B1) is bonded to the linking group.

[0059]

[0060] Examples of such linking groups include linking groups having two or three aromatic rings (corresponding to unit structure A). Specific examples of divalent or trivalent linking groups include the following divalent linking groups (L1) exemplified in the above formula (B11): [X １ represents a single bond, a methylene group, an oxygen atom, a sulfur atom, or —N(R ５ )-, R ５ represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms (including a chain hydrocarbon and a cyclic hydrocarbon (which may be aromatic or non-aromatic)). )], examples thereof include divalent or trivalent linking groups of the following formulae (L2) and (L3).

[0061] [X ２ is a methylene group, an oxygen atom, -N(R ６ )-, R ６represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aromatic hydrocarbon group having 5 to 20 carbon atoms.]

[0062] Examples also include divalent linking groups such as those of the following formula (L4), which can form a covalent bond with the linking carbon atom by an addition reaction between an acetylide and a ketone.

[0063]

[0064] (III-3-B13) Note that, when at least one of R and R' in formula (B1) is an aromatic ring, the aromatic ring [see, for example, Ar in formula (B12) below] may additionally be bonded to another unit structure B. That is, when at least one of R and R' in formula (BI) is an aromatic ring, if such aromatic ring is bonded to another unit structure B and one bond in formula (B1) is bonded to the aromatic ring of unit structure A, the unit structure represented by formula (B1) can be considered as a unit structure C equivalent to composite unit structure A-B. Therefore, the structure represented by formula (B1) may be included in composite unit structure A-B as such unit structure C. In this case, the remaining bond in formula (B1) may be bonded, for example, to a polymer terminal group or to an aromatic ring in another polymer chain to form a crosslink.

[0065] For example, the following formula (C1): When one bond of the linking carbon atom is bonded to a polymer terminal T (hydrogen atom; various functional groups such as a hydroxyl group or an unsaturated aliphatic hydrocarbon group; a terminal unit structure A; a unit structure A in another polymer chain, etc.), as in the above, at least one composite unit structure A-B can be substituted as a unit structure C equivalent to the composite unit structure A-B. That is, the aromatic ring [Ar in formula (C1)] in formula (C1) may be bonded to another unit structure B, and the polymer chain may be extended by bonding to the aromatic ring of unit structure A via a bond from the remaining linking carbon atom shown in formula (C1). Note that, when a bond with unit structure A is mentioned in this specification, it may be interpreted as including a bond with the aromatic ring in unit structure C, even if not specified. Furthermore, when a bond with unit structure B is mentioned in this specification, it may be interpreted as including a bond with the linking carbon atom in unit structure C, even if not specified.

[0066] (III-3-B14) Some specific examples of the structural unit B containing the structure represented by formula (B1) are as follows. * basically indicates the bonding site with the structural unit A. Needless to say, the structure may contain the exemplified structure as a part of the whole.

[0067]

[0068] (III-3-B20) Formula (B2) In formula (B2), Z ０ represents an aromatic ring residue or an aliphatic ring residue having 6 to 30 carbon atoms, which may have a substituent, or an organic group in which two aromatic or aliphatic rings are linked by a single bond. Examples of the organic group in which two aromatic or aliphatic rings are linked by a single bond include divalent residues such as biphenyl, cyclohexylphenyl, and bicyclohexyl. Z in formula (B2) ０ In the definitions of (I-1), the terms "aromatic ring", "substituent", "aliphatic ring", and "residue" are the same as those explained in (I-2), (I-3), and (I-5) above.

[0069] J １ and J ２each independently represents a divalent organic group which may have a direct bond or a substituent. The divalent organic group is preferably a linear or branched alkylene group having 1 to 6 carbon atoms which may be substituted with a hydroxyl group, an aryl group (e.g., a phenyl group, a substituted phenyl group), or a halo group (e.g., fluorine) as a substituent. Examples of linear alkylene groups include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, and a hexylene group.

[0070] (III-3-B21) Furthermore, the unit structure containing the structure represented by formula (B2) may contain a structure in which two or three identical or different structures represented by formula (B2) are bonded to a divalent or trivalent linking group to form a dimer or trimer structure, as in (III-3-B12) above for formula (B1).

[0071] (III-3-B22) In addition, in the embodiment where the formula (B2) contains an aromatic ring [Z in the formula (B2)] ０ ], and therefore, similar to (III-3-B13) of the formula (B1), the aromatic ring [for example, Z ０ Ａｒ [an aromatic ring in the formula (B2)] may additionally be bonded to another unit structure B [the longitudinal bond in formula (B21)]. That is, since formula (B2) includes an embodiment containing an aromatic ring, in such an embodiment, when the aromatic ring of formula (B2) is bonded to another unit structure B and one bond in formula (B2) is bonded to the aromatic ring of unit structure A, the unit structure represented by formula (B2) can be regarded as a unit structure C equivalent to the composite unit structure A-B. Therefore, such unit structure C may be included in the structure represented by formula (B2) in the composite unit structure A-B. In this case, the other bond in formula (B2) may be bonded, for example, to a polymer terminal group or to an aromatic ring in another polymer chain to form a crosslink.

[0072] [In formula (B21), Z ０ Ａｒis an aromatic ring residue having 6 to 30 carbon atoms which may have a substituent, or an organic group in which two aromatic rings or aliphatic rings are linked by a single bond, and which has at least one aromatic ring; Z ０ Ａｒ The connecting hand extending downwards is Z ０ Ａｒ extending from the aromatic ring in J １ and J ２ is defined as in formula (B2). In this case, the following formula (C2): [In formula (C2), Z ０ Ａｒ , J １ and J ２ is defined as in formula (B21), and T represents a polymer terminal. ], when one bond of the linking carbon atom is bonded to a polymer terminal T (hydrogen atom; various functional groups such as a hydroxyl group or an unsaturated aliphatic hydrocarbon group, a terminal unit structure A, a unit structure A in another polymer chain, etc.), it can also be replaced with at least one composite unit structure A-B as one unit structure C equivalent to the composite unit structure A-B. That is, the aromatic ring in formula (C2) [Z in formula (C2) ０ Ａｒ The aromatic ring in the unit structure A may be bonded to another unit structure B, and the remaining connecting carbon atom shown in formula (C2) may be bonded to the aromatic ring of the unit structure A, thereby extending the polymer chain.

[0073] (III-3-B23) Some specific examples of unit structures containing the structure represented by formula (B2) are as follows. * indicates the bonding site with unit structure A. Needless to say, the unit structure may contain the exemplified structure as a part of the whole.

[0074]

[0075] (III-3-B30) Formula (B3) [Formula (B3)]

[0076] In formula (B3), Z is a monocyclic ring or a bicyclic, tricyclic, or tetracyclic fused ring having 4 to 25 carbon atoms, which may have a substituent. The number of carbon atoms referred to here means only the number of carbon atoms constituting the ring skeleton of the monocyclic ring or the bicyclic, tricyclic, or tetracyclic fused ring excluding substituents, and does not include the number of heteroatoms constituting the heterocyclic ring when the monocyclic ring or fused ring is a heterocyclic ring.

[0077] The monocycle is a non-aromatic monocycle; at least one of the monocycles constituting the bicycle, tricycle, or tetracycle is a non-aromatic monocycle, and the remaining monocycles may be aromatic or non-aromatic monocycles.

[0078] The monocyclic or bicyclic, tricyclic, or tetracyclic fused ring may further form a fused ring with one or more aromatic rings to form a pentacyclic or higher fused ring, and the number of carbon atoms in the pentacyclic or higher fused ring is preferably 40 or less. The number of carbon atoms referred to here means only the number of carbon atoms constituting the ring skeleton of the pentacyclic or higher fused ring excluding substituents, and does not include the number of heteroatoms constituting the heterocyclic ring when the pentacyclic or higher fused ring is a heterocyclic ring.

[0079] X and Y may be the same or different and each represent -CR 31 R 32 represents a - group, and R 31 and R 32 are the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms.

[0080] x and y represent the numbers X and Y, respectively, and each independently represents 0 or 1.

[0081] is bonded to any carbon atom (referred to as "carbon atom 1") constituting the non-aromatic monocyclic ring of Z (when x = 1) or extends from carbon atom 1 (when x = 0), is bonded to any carbon atom (referred to as "carbon atom 2") constituting the non-aromatic monocycle of Z (when y = 1) or extends from carbon atom 2 (when y = 0), and carbon atom 1 and carbon atom 2 may be the same or different, and when different, they may belong to the same non-aromatic monocycle or different non-aromatic monocycles.

[0082] Furthermore, formula (B3) may optionally contain linking carbon atoms other than carbon atom 1 and carbon atom 2 [see (III-3-B33) below]. When Z is a tricyclic or higher fused ring, the permutation relationship between one or two non-aromatic monocycles to which carbon atoms 1 and 2 in formula (B3) belong and the remaining monocycles in the fused ring is arbitrary, and when carbon atom 1 and carbon atom 2 belong to different non-aromatic monocycles (referred to as "non-aromatic monocycle 1" and "non-aromatic monocycle 2," respectively), the permutation relationship between non-aromatic monocycle 1 and non-aromatic monocycle 2 in the fused ring is also arbitrary.

[0083] (III-3-B31) An example of a unit structure that is one aspect of formula (B3) is formula (B31) shown below. Z is a 4- to 17-membered monocyclic, bicyclic, tricyclic, or tetracyclic organic group which may have a substituent, and of the one or more monocyclic rings constituting the organic group, at least one monocyclic ring is a non-aromatic monocyclic ring, and the organic group may have a maximum of four non-aromatic monocyclic rings. The other monocyclic rings are aromatic rings, and may further form fused rings with additional aromatic monocyclic rings to form a polycyclic organic group having five or more rings. For details on non-aromatic monocyclic rings, non-aromatic bicyclic rings, non-aromatic tricyclic rings, and non-aromatic tetracyclic rings, see (I-5) above. Examples of aromatic monocyclic rings or aromatic rings are similar to those exemplified in (I-3) above, with preferred examples including an optionally substituted benzene ring, naphthalene ring, anthracene ring, and pyrene ring. The non-aromatic monocyclic ring may contain C or C' as defined in formula (B31) [i.e., the linking carbon atom as defined in (I-1) above], each representing one carbon atom in the group of atoms constituting the cyclic portion. Among these, the linking carbon atom C is always present, but the linking carbon atom C' is optional, and n in formula (B31) representing the number of C' is 0 to 2, preferably 0. X, Y, X', and Y' may be the same or different and represent -CR 1 R 2 represents a - group, and R 1 and R 2are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, but are merely optional linking groups, and therefore x, y, x', and y', which represent the numbers X, Y, X', and Y' (0 or 1), may all be 0. p, q, p', and q' represent the number of bonds and each independently represents 0 or 1, but 0 means that it is replaced with a hydrogen atom. In principle, these bonds bond to aromatic rings of other structures (corresponding to unit structure A) having an aromatic ring, but at the polymer terminals, they bond to polymer terminal groups [see (III-3-B4) below]. Since at least two bonds are required to form a polymer chain, when n is 0, p and q are 1; when n is 1, provided that there is at least one bond extending from C and C' (so-called connecting carbon atoms), at least one of p and q and at least one of p' and q' is 1; similarly, when n is 2, at least one of p and q and at least one of p' and q' of each C' is 1. When there are two or more bonds, these extra bonds may be bonded, for example, to a polymer end group or to an aromatic ring in another polymer chain to form a crosslink.

[0084] (III-3-B32) As in (III-3-B12) above for Formula (B1), two or three identical or different structures of Formula (B3) may be bonded to a divalent or trivalent linking group to form a dimer or trimer structure. In the case of Formula (B31), one of p and q, which are the bond valences in each structure of Formula (B31), is bonded to the linking group. And, n is not 0, and one bond valence is provided from the linking carbon atom C and at least one bond valence is provided from the linking carbon atom C'.

[0085] (III-3-B33) Specific examples of the organic group containing the structure represented by formula (B3) are as follows. The bonding site with the unit structure A is not particularly limited. Needless to say, the structure may contain the exemplified structure as a part of the whole.

[0086] Examples include those with more than two bond valences (*), and these excess bond valences can be used for bonding to aromatic rings in other polymer chains, crosslinking, etc.

[0087]

[0088] (III-3-B34) When Z in formula (B3) contains an aromatic ring, the aromatic ring [for example, Ar in formula (B32) below] １ [See reference] may additionally be bonded to another unit structure B.

[0089] In formula (B32), Z １ is at least one non-aromatic monocyclic ring, Ar １ is Z １ and Z and Ar represent at least one aromatic monocyclic ring forming a condensed ring with a non-aromatic monocyclic ring of the formula １ The group as a whole constitutes a bicyclic, tricyclic, tetracyclic, or pentacyclic fused ring, optionally having a substituent, having 8 to 25 carbon atoms. The number of carbon atoms referred to here means only the number of carbon atoms constituting the ring skeleton of the bicyclic, tricyclic, or tetracyclic fused ring, excluding substituents, and does not include the number of heteroatoms constituting the heterocyclic ring when the bicyclic, tricyclic, or tetracyclic fused ring is a heterocyclic ring.

[0090] The bicyclic, tricyclic, tetracyclic, or pentacyclic organic group may further form a fused ring with one or more aromatic rings to form a hexacyclic or higher ring, and the hexacyclic or higher fused ring preferably has 40 or less carbon atoms. The number of carbon atoms referred to here means only the number of carbon atoms constituting the ring skeleton of the hexacyclic or higher fused ring excluding substituents, and does not include the number of heteroatoms constituting the heterocyclic ring when the hexacyclic or higher fused ring is a heterocyclic ring.

[0091] In addition, Z in the cyclic organic group １ and one or more non-aromatic monocyclic rings belonging to the group １ The order and positional relationship of one or more aromatic monocyclic rings belonging to the formula (I) includes any order. １ two or more non-aromatic monocyclic rings belonging to Ar １ When there are two or more aromatic monocyclic rings belonging to Z １ and non-aromatic monocyclic rings belonging to Ar１ and aromatic monocyclic rings belonging to the formula (I) may be arranged alternately to form a condensed ring.

[0092] Furthermore, X, Y, x, and y are defined as in formula (B3).

[0093] In this case, the following formula (C3): [In formula (C3), Z １ , Ar １ , X, Y, x, and y are the same as those defined in formula (B32), and T represents a polymer terminal. ], when one bond of the linking carbon atom is bonded to a polymer terminal T (hydrogen atom; various functional groups such as a hydroxyl group or an unsaturated aliphatic hydrocarbon group, a terminal unit structure A, a unit structure A in another polymer chain, etc.), it can also be replaced with at least one composite unit structure A-B as one unit structure C equivalent to the composite unit structure A-B. That is, the aromatic ring in formula (C3) [Ar in formula (C3)] １ and another unit structure B, and at the same time, a bond from the remaining linking carbon atom shown in formula (C3) is bonded to the aromatic ring of unit structure A, thereby extending the polymer chain. Alternatively, another unit structure C equivalent to the composite unit structure A-B may also include a unit structure containing a structure shown in formula (C4) below. In formula (C4), Z １ is at least one non-aromatic monocyclic ring, Ar １ represents at least one aromatic monocyclic ring, Z and Ar １ The whole constitutes a cyclic organic group which is an 8- to 17-membered bicyclic or higher fused ring which may have a substituent. The arrangement and order of the aromatic monocyclic rings and non-aromatic monocyclic rings in the cyclic organic group may be arbitrary. １ In any of the non-aromatic monocycles, there is a C represented by formula (C4) [i.e., the linking carbon atom referred to in (I-1) above], which represents one carbon atom among the atomic group constituting the cyclic portion. X, Y, x, and y are defined as in formula (B31). T represents a polymer end group or an aromatic ring residue Ar ２represents. p represents one bond for a covalent bond with the aromatic ring of unit structure A (which may include the aromatic ring in the second unit structure C). On the other hand, k and m represent the number of bonds for a covalent bond with unit structure B (which may include the third unit structure C), and each independently k represents 0 to 2, m represents 0 or 1, and at least one of k and m is not 0 (when k or m is 0, this means that the bond is replaced with a hydrogen atom). When k is 2, the two bonds of k may extend from the same aromatic monocycle or from different aromatic monocycles. When k is 2, or when k is 1 and m is 1, the extra bond forms a polymer end group or a crosslink with another polymer chain.

[0094] (III-3-B35) As a more specific structure of formula (C3) or (C4), for example, in the following formula (C31), T in formula (C3) is a hydrogen atom which is a terminal group, and p and k which can be bonding hands are １ and k ２ Among them, p and k １ , or p and k ２ This can result in one unit structure C equivalent to the composite unit structure AB.

[0095] In addition, k １ Tok ２ It can also function as unit structure A.

[0096] In addition, the following formula (C32) shows an example where T in formula (C3) is a phenyl group. In this example, p and k, which can be bonding hands, １ , k ２ and m, p and k １ , p and k ２ , or p and m can result in a single unit structure C equivalent to the composite unit structure AB.

[0097] In addition, k １ Tok ２ , k １ and m or k ２ and m, it can also function as a unit structure A.

[0098] Some specific examples of the structural unit C of formula (C3) (a structural unit equivalent to the composite structural unit A-B) are as follows. * indicates the bonding site with structural unit A.

[0099] In the unit structure C, a bond extends from the aromatic ring in these structures to bond to the unit structure B, but in the specific examples below, such a bond is omitted. Needless to say, the unit structure may include the exemplified structure as a part of the whole.

[0100] In the above specific examples, when there is no bond from the aromatic ring, it can be a specific example of a polymer terminal.

[0101] (III-3-B4) At the polymer terminal, the structural unit B forms a covalent bond with a terminal group (polymer terminal group). Such a polymer terminal group may or may not be an aromatic ring derived from the structural unit A. Examples of such a polymer terminal group include a hydrogen atom, an optionally substituted aromatic ring residue, and an organic group containing an optionally substituted unsaturated aliphatic hydrocarbon residue [see the substituent corresponding to T in formula (C3) or (C4) in the specific example of (III-3-B35)].

[0102] (III-3-S) [Synthesis Method] Novolak resins having a structure represented by formula (AB) can be prepared by known methods. For example, they can be prepared by condensing a ring-containing compound represented by H-A-H with an oxygen-containing compound represented by OHC-B, O═C-B, HO-B-OH, RO-B-OR, or the like. In the formula, A and B have the same meanings as above. R represents a halogen or an alkyl group having approximately 1 to 3 carbon atoms. The ring-containing compound and the oxygen-containing compound may be used alone or in combination of two or more. In this condensation reaction, the oxygen-containing compound can be used in a ratio of 0.1 to 10 moles, preferably 0.1 to 2 moles, per mole of the ring-containing compound. Examples of catalysts that can be used in the condensation reaction include mineral acids such as sulfuric acid, phosphoric acid, and perchloric acid; organic sulfonic acids such as p-toluenesulfonic acid, p-toluenesulfonic acid monohydrate, methanesulfonic acid, and trifluoromethanesulfonic acid; and carboxylic acids such as formic acid and oxalic acid. The amount of catalyst used varies depending on the type of catalyst used, but is typically 0.001 to 10,000 parts by mass, preferably 0.01 to 1,000 parts by mass, and more preferably 0.05 to 100 parts by mass per 100 parts by mass of the ring-containing compound (or the total amount of ring-containing compounds if multiple types are used). The condensation reaction can be carried out without a solvent, but is typically carried out using a solvent. The solvent is not particularly limited as long as it can dissolve the reaction substrates and does not inhibit the reaction. Examples of the solvent include 1,2-dimethoxyethane, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, tetrahydrofuran, tetrahydropyran, 4-methyltetrahydropyran, dioxane, 1,2-dichloromethane, 1,2-dichloroethane, toluene, N-methylpyrrolidone, and dimethylformamide. The condensation reaction temperature is typically 40°C to 200°C, preferably 100°C to 180°C. The reaction time varies depending on the reaction temperature, but is usually 5 minutes to 50 hours, preferably 5 minutes to 24 hours. The weight average molecular weight of the novolak resin according to one embodiment of the present invention is usually 500 to 100,000, preferably 600 to 50,000, 700 to 10,000, or 800 to 8,000.

[0103] [IV. One or more bases B ２ (IV-1) One or more bases B, which are additional base components in the underlayer film-forming composition according to the present invention ２ This allows the base to trap the acid generated during firing, slowing down the hardening rate, and as a result, SiO ２ A cured film with high flatness and high embedding properties can be obtained with various film types such as TiN, SiN, etc. Furthermore, since there is no influence from the acid generator and the storage stability of the polymer, which is the main component of the resist underlayer film, can be ensured, a film can be formed that does not discolor and does not dissolve in photoresist solvents. (IV-2) From the viewpoint of more effectively trapping the acid generated during baking, a base B ２ The amount of the sulfonate anion group (SO ) contained in the thermal acid generator (a) is ３ － When the amount of base required to neutralize the same number of moles of sulfonic acid (monobasic acid) as the sulfonic acid anion group (SO ) contained in the thermal acid generator (a) is taken as 1 equivalent, the sulfonic acid anion group (SO ) is preferably 0.05 to 3.0, more preferably 0.1 to 2.5, and even more preferably 0.2 to 2.0. ３ － When the amount of base required to neutralize the same number of moles of sulfonic acid (monobasic acid) as the base B is taken as 1 equivalent, １ and base B ２ Preferably, a base having a pKa greater than that of pyridine in the thermal acid generator (a), more preferably a base having a pKa of 6.5 or greater, is present in an amount of 1.05 equivalents or greater, more preferably 1.1 equivalents or greater, and even more preferably 1.2 equivalents or greater. On the other hand, from the viewpoint of cost commensurate with the effect, the sulfonate anion group (SO ３ － When the amount of base required to neutralize the same number of moles of sulfonic acid (monobasic acid) as the base B is taken as 1 equivalent, １ and base B ２ Preferably, a base having a pKa greater than that of pyridine, more preferably a base having a pKa of 6.5 or greater, is present in an amount of 2 equivalents or less, more preferably 1.8 equivalents or less, and even more preferably 1.5 equivalents or less.

[0104] (IV-3) In the present invention, specific examples of bases having a pKa greater than that of pyridine, preferably a base having a pKa of 6.5 or greater, include N-methylmorpholine, N,N-diethylaniline, N-isobutylmorpholine, and N-allylmorpholine. For measuring pKa, for example, the pKa value in water, preferably at 25°C, can be measured by potentiometric titration [see, for example, S. Xu et al., "Dissociation constants of alkanolamines", Can. J. Chem. 71, 1048 (1993)] and compared. R. Linnell, J. Org. Chem. 1960, 25, 2, 290-290; M. Kotake, ed., "Great Organic Chemistry, Supplementary Volume 2, Handbook of Organic Chemistry Constants", p. 584 (1963), (Asakura Shoten); HK Hall Jr. et al., Tetrahedron Letters 53 (2012) 1830-1832 can also be used as references.

[0105] [V. Solvent] (V-1) The resist underlayer film-forming composition according to the present invention contains a solvent. The solvent is not particularly limited as long as it can dissolve (a) the thermal acid generator, (b) the aromatic ring-containing polymer, and (c) the base, as well as any optional components added as needed. In particular, when the resist underlayer film-forming composition is used in the form of a homogeneous solution for nanoimprinting, it is recommended to use a solvent commonly used in lithography processes in combination with the resist underlayer film-forming composition, taking into account its coating performance. Examples of such solvents include methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, methyl isobutyl carbinol, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoether ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, ethyl, methyl pyruvate, ethyl pyruvate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether, ethyl lactate,Propyl lactate, isopropyl lactate, butyl lactate, isobutyl lactate, methyl formate, ethyl formate, propyl formate, isopropyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl acetate, ethyl acetate, amyl acetate, isoamyl acetate, hexyl acetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, butyl propionate, isobutyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, isopropyl butyrate, butyl butyrate, isobutyl butyrate, ethyl hydroxyacetate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutyrate, ethyl methoxyacetate, Examples of suitable solvents include ethyl acetoacetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-methoxybutyl acetate, 3-methoxypropyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, methyl acetoacetate, toluene, xylene, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, cyclopentanone, cyclohexanone, N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpyrrolidone, 4-methyl-2-pentanol, and γ-butyrolactone. These solvents can be used alone or in combination of two or more.

[0106] (V-2) From the viewpoint of uniformly dissolving (a) the acid thermal generator, (b) the polymer containing an aromatic ring, and (c) the base, as well as optional components (such as an aminoplast crosslinking agent or a phenoplast crosslinking agent), a compound having an alcoholic hydroxyl group or a compound having a group capable of forming an alcoholic hydroxyl group is preferred as the solvent. Preferred examples of such a solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, propylene glycol propyl ether acetate, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, Examples of the hydroxypropyl ether include propylene glycol monomethyl ether, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, and butyl lactate. Among these, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, methyl 2-hydroxy-2-methylpropionate, ethyl lactate, and cyclohexanone are more preferred, and propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl 2-hydroxy-2-methylpropionate, ethyl lactate, and cyclohexanone are most preferred.

[0107] (V-3) It may also contain a solvent having a boiling point of 160° C. or higher. For example, the following compound described in WO 2018 / 131562 (A1) can be used. (R in formula (i) １ , R ２ and R ３ each represents a hydrogen atom, an oxygen atom, a sulfur atom, or an alkyl group having 1 to 20 carbon atoms which may be interrupted by an amide bond, and may be the same or different from each other and may be bonded to each other to form a ring structure.) Alternatively, 1,6-diacetoxyhexane (boiling point 260°C) and tripropylene glycol monomethyl ether (boiling point 242°C) described in JP-A-2021-84974, as well as various other high-boiling point solvents described in paragraph 0082 of the same publication, can be preferably used. Alternatively, dipropylene glycol monomethyl ether acetate (boiling point 213°C), diethylene glycol monoethyl ether acetate (boiling point 217°C), diethylene glycol monobutyl ether acetate (boiling point 247°C), dipropylene glycol dimethyl ether (boiling point 171°C), dipropylene glycol monomethyl ether (boiling point 187°C), dipropylene glycol monobutyl ether (boiling point 231°C), tripropylene glycol monomethyl ether (boiling point 242°C), γ-butyrolactone (boiling point 204°C), benzyl alcohol (boiling point 205°C), propylene carbonate (boiling point 242°C), tetraethylene glycol dimethyl ether (boiling point 275°C), 1,6-diacetoxyhexane (boiling point 260°C), dipropylene glycol (boiling point 230°C), 1, 3-butylene glycol diacetate (boiling point 232° C.) and various other high boiling point solvents described in paragraphs 0023 to 0031 of the publication can be preferably used.

[0108] [VI. Other Optional Components] In addition to the above, the resist underlayer film-forming composition according to the present invention may contain a crosslinking agent, a surfactant, a light absorber, a rheology adjuster, an adhesion aid, and the like, as needed.

[0109] (VI-1: Aminoplast Crosslinking Agents) Examples of aminoplast crosslinking agents include highly alkylated, alkoxylated, or alkoxyalkylated melamine, benzoguanamine, glycoluril, urea, and polymers thereof. Preferred are crosslinking agents having at least two crosslinking substituents, such as methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxymethylated benzoguanamine, methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, or methoxymethylated thiourea. Condensates of these compounds can also be used. Furthermore, crosslinking agents with high heat resistance can be used. Preferred crosslinking agents with high heat resistance include compounds containing crosslinking substituents with an aromatic ring (e.g., a benzene ring or a naphthalene ring) in the molecule. Preferably, the crosslinking agent is at least one selected from the group consisting of tetramethoxymethylglycoluril and hexamethoxymethylmelamine. The aminoplast crosslinking agent may be used alone or in combination of two or more. The aminoplast crosslinking agent can be produced by a method known per se or a method similar thereto, or a commercially available product may be used. The amount of the aminoplast crosslinking agent used varies depending on the coating solvent used, the base substrate used, the required solution viscosity, the required film shape, etc., but is 0.001 mass% or more, 0.01 mass% or more, 0.05 mass% or more, 0.5 mass% or more, or 1.0 mass% or more, and 80 mass% or less, 50 mass% or less, 40 mass% or less, 20 mass% or less, or 10 mass% or less, based on the total solids content of the resist underlayer film-forming composition of the present invention. Some specific examples are as follows.

[0110] (VI-2: Phenoplast Crosslinking Agents) Examples of phenoplast crosslinking agents include highly alkylated, alkoxylated, or alkoxyalkylated aromatics, polymers thereof, and the like. Preferred are crosslinking agents having at least two crosslink-forming substituents per molecule, such as 2,6-dihydroxymethyl-4-methylphenol, 2,4-dihydroxymethyl-6-methylphenol, bis(2-hydroxy-3-hydroxymethyl-5-methylphenyl)methane, bis(4-hydroxy-3-hydroxymethyl-5-methylphenyl)methane, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, bis(3-formyl-4-hydroxyphenyl)methane, bis(4-hydroxy-2,5-dimethylphenyl)formylmethane, and α,α-bis(4-hydroxy-2,5-dimethylphenyl)-4-formyltoluene. Condensates of these compounds can also be used. Furthermore, crosslinking agents with high heat resistance can be used as the crosslinking agent. As a crosslinking agent with high heat resistance, a compound containing a crosslinking substituent having an aromatic ring (e.g., a benzene ring or a naphthalene ring) in the molecule can be preferably used. The phenoplast crosslinking agent may be used alone or in combination of two or more. The phenoplast crosslinking agent can be produced by a method known per se or a method equivalent thereto, or a commercially available product may be used. The amount of the phenoplast crosslinking agent used varies depending on the coating solvent used, the base substrate used, the required solution viscosity, the required film shape, etc., but is 0.001 mass% or more, 0.01 mass% or more, 0.05 mass% or more, 0.5 mass% or more, or 1.0 mass% or more, and 80 mass% or less, 50 mass% or less, 40 mass% or less, 20 mass% or less, or 10 mass% or less, based on the total solids content of the resist underlayer film-forming composition of the present invention. In addition to the above, other examples of such compounds include compounds having a partial structure of the following formula (4) and polymers or oligomers having a repeating unit of the following formula (5). The above R １１ , R １２ , R １３ , and R １４is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the above-mentioned examples of these alkyl groups can be used. n1 is an integer of 1 to 4, n2 is an integer of 1 to (5-n1), and (n1+n2) is an integer of 2 to 5. n3 is an integer of 1 to 4, n4 is an integer of 0 to (4-n3), and (n3+n4) is an integer of 1 to 4. Oligomers and polymers having a repeating unit structure of 2 to 100 or 2 to 50 can be used. Some specific examples are as follows:

[0111] (VI-3: Surfactant) The resist underlayer film-forming composition according to the present invention can contain a surfactant in order to prevent the generation of pinholes, striations, etc. and further improve coatability against surface irregularities. Examples of the surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkyl aryl ethers such as polyoxyethylene octyl phenol ether and polyoxyethylene nonyl phenol ether; polyoxyethylene-polyoxypropylene block copolymers; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate; polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate; Examples of suitable surfactants include nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters, such as polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate; fluorosurfactants such as EFTOP EF301, EF303, and EF352 (trade names, manufactured by Tochem Products Co., Ltd.), Megafac F171, F173, R-30, and R-40 (trade names, manufactured by Dainippon Ink Co., Ltd.), Fluorad FC430 and FC431 (trade names, manufactured by Sumitomo 3M Limited), Asahiguard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (trade names, manufactured by Asahi Glass Co., Ltd.); and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.). The amount of these surfactants to be added is usually 2.0 mass % or less, and preferably 1.0 mass % or less, based on the total solid content of the resist underlayer film-forming composition of the present invention. These surfactants may be added alone or in combination of two or more.

[0112] (VI-4: Other Additives) In addition to the crosslinking catalyst of formula (I), the resist underlayer film-forming composition according to the present invention may also contain, as a catalyst for accelerating the crosslinking reaction, acidic compounds such as citric acid, thermal acid generators such as 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, and other organic sulfonic acid alkyl esters, onium salt-based photoacid generators such as bis(4-t-butylphenyl)iodonium trifluoromethanesulfonate and triphenylsulfonium trifluoromethanesulfonate, halogen-containing compound-based photoacid generators such as phenyl-bis(trichloromethyl)-s-triazine, and sulfonic acid-based photoacid generators such as benzoin tosylate and N-hydroxysuccinimide trifluoromethanesulfonate. Examples of the light-absorbing agent include commercially available light-absorbing agents described in "Technology and Market of Industrial Dyes" (CMC Publishing) and "Dye Handbook" (edited by the Society of Organic Synthetic Chemistry), for example, C.I. C.I. Disperse Yellow 1, 3, 4, 5, 7, 8, 13, 23, 31, 49, 50, 51, 54, 60, 64, 66, 68, 79, 82, 88, 90, 93, 102, 114 and 124; C.I. Disperse Orange 1, 5, 13, 25, 29, 30, 31, 44, 57, 72 and 73; C.I. Disperse Red 1, 5, 7, 13, 17, 19, 43, 50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199 and 210; C.I. Disperse Violet 43; C.I. Disperse Blue 96; C.I. Fluorescent Brightening Agent 112, 135, and 163; C.I. Solvent Orange 2 and 45; C.I. Solvent Red 1, 3, 8, 23, 24, 25, 27, and 49; C.I. Pigment Green 10; C.I. Pigment Brown 2, and the like, can be suitably used. The above-mentioned light-absorbing agent is usually blended in an amount of 10% by mass or less, preferably 5% by mass or less, based on the total solids content of the resist underlayer film-forming composition according to the present invention. The rheology control agent is added mainly to improve the fluidity of the resist underlayer film-forming composition and, particularly in the baking step, to improve the film thickness uniformity of the resist underlayer film and the filling ability of the resist underlayer film-forming composition into holes.Specific examples include phthalic acid derivatives such as dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, and butyl isodecyl phthalate; adipic acid derivatives such as di-n-butyl adipate, diisobutyl adipate, diisooctyl adipate, and octyldecyl adipate; maleic acid derivatives such as di-n-butyl maleate, diethyl maleate, and dinonyl maleate; oleic acid derivatives such as methyl oleate, butyl oleate, and tetrahydrofurfuryl oleate; and stearic acid derivatives such as n-butyl stearate and glyceryl stearate. These rheology modifiers are typically blended in an amount of less than 30% by mass based on the total solids content of the resist underlayer film-forming composition of the present invention. The adhesion promoter is added primarily to improve the adhesion between the substrate or resist and the resist underlayer film-forming composition, particularly to prevent peeling of the resist during development. Specific examples include chlorosilanes such as trimethylchlorosilane, dimethylvinylchlorosilane, methyldiphenylchlorosilane, and chloromethyldimethylchlorosilane; alkoxysilanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethylvinylethoxysilane, diphenyldimethoxysilane, and phenyltriethoxysilane; silazanes such as hexamethyldisilazane, N,N'-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine, and trimethylsilylimidazole; and vinyltrichlorosilane. Examples of the adhesion aid include silanes such as silane, γ-chloropropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-glycidoxypropyltrimethoxysilane; heterocyclic compounds such as benzotriazole, benzimidazole, indazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, urazole, thiouracil, mercaptoimidazole, and mercaptopyrimidine; and ureas such as 1,1-dimethylurea and 1,3-dimethylurea, or thiourea compounds. These adhesion aids are blended in an amount of usually less than 5% by mass, and preferably less than 2% by mass, based on the total solids content of the resist underlayer film-forming composition of the present invention.The resist underlayer film-forming composition according to the present invention has a solids content of 0.1 to 70% by mass, or 0.1 to 60% by mass. The solids content is the content of all components of the resist underlayer film-forming composition excluding the solvent. The solids content may contain a crosslinkable resin in an amount of 1 to 99.9% by mass, or 50 to 99.9% by mass, or 50 to 95% by mass, or 50 to 90% by mass.

[0113] [VII: Resist Underlayer Film] A resist underlayer film can be formed using the resist underlayer film-forming composition according to the present invention as follows: ２The resist underlayer film-forming composition according to one embodiment of the present invention is applied to a substrate (e.g., a silicon nitride substrate (SiN substrate), a silicon oxynitride substrate (SiON substrate), a titanium nitride substrate (TiN substrate), a tungsten substrate (W substrate), a glass substrate, an ITO substrate, a polyimide substrate, or a substrate coated with a low dielectric constant material (low-k material)) by a suitable application method such as a spinner or coater, and then baked using a heating means such as a hot plate to form a resist underlayer film. Baking conditions are appropriately selected from a baking temperature of 80°C to 600°C and a baking time of 0.3 to 60 minutes. Preferably, the baking temperature is 150°C to 400°C, more preferably 150°C to 350°C, and the baking time is 0.5 to 2 minutes. The atmospheric gas during baking may be air, or an inert gas such as nitrogen or argon. In one embodiment, it is particularly preferable that the oxygen concentration is 1% or less. The thickness of the underlayer film formed here is, for example, 10 to 1,000 nm, or 20 to 500 nm, or 30 to 400 nm, or 50 to 300 nm. Furthermore, by using a quartz substrate as the substrate, a replica (mold replica) of a quartz imprint mold can be produced. Furthermore, an adhesion layer and / or a silicone layer containing 99% by mass or less, or 50% by mass or less, of Si can be formed by coating or vapor deposition on the resist underlayer film of one embodiment of the present invention. For example, in addition to the adhesion layer described in JP 2013-202982 A and JP 5827180 A, and the method of forming the silicon-containing resist underlayer film (inorganic resist underlayer film)-forming composition described in WO 2009 / 104552 A1 by spin coating, a Si-based inorganic material film can also be formed by a CVD method or the like. Furthermore, by applying the resist underlayer film-forming composition of one embodiment of the present invention to a semiconductor substrate having a portion with a step and a portion without a step (a so-called stepped substrate) and baking it, the step between the portion with a step and the portion without a step can be reduced.

[0114] [VIII: Method for Manufacturing a Semiconductor Device] (VIII-1) (i) A method for manufacturing a semiconductor device according to one aspect of the present invention includes the steps of: forming a resist underlayer film on a semiconductor substrate using a resist underlayer film-forming composition according to one aspect of the present invention; forming a resist film on the formed resist underlayer film; forming a resist pattern by irradiating the formed resist film with light or an electron beam and developing it; etching the resist underlayer film through the formed resist pattern; and processing a semiconductor substrate through the patterned resist underlayer film. (ii) A method for manufacturing a semiconductor device according to one aspect of the present invention includes the steps of: forming a resist underlayer film on a semiconductor substrate using a resist underlayer film-forming composition according to one aspect of the present invention; forming a hard mask on the formed resist underlayer film; forming a resist film on the formed hard mask; forming a resist pattern by irradiating the formed resist film with light or an electron beam and developing it; etching the hard mask through the formed resist pattern; etching the resist underlayer film through the patterned hard mask; and processing a semiconductor substrate through the patterned resist underlayer film. (iii) A method for manufacturing a semiconductor device according to one aspect of the present invention includes the steps of: forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to one aspect of the present invention; forming a hard mask on the formed resist underlayer film; forming a resist film on the formed hard mask; forming a resist pattern by irradiating the formed resist film with light or an electron beam and developing it; etching the hard mask using the formed resist pattern; etching the resist underlayer film using the patterned hard mask; removing the hard mask; and processing a semiconductor substrate using the patterned resist underlayer film.(iv) A method for manufacturing a semiconductor device according to one embodiment of the present invention includes the steps of: forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to one embodiment of the present invention; forming a hard mask on the formed resist underlayer film; forming a resist film on the formed hard mask; forming a resist pattern by irradiating the formed resist film with light or an electron beam and developing it; etching the hard mask using the formed resist pattern; etching the resist underlayer film using the patterned hard mask; removing the hard mask; and forming a vapor-deposited film (spacer) on the resist underlayer film after removing the hard mask; processing the vapor-deposited film (spacer) by etching; removing the patterned resist underlayer film to leave the patterned vapor-deposited film (spacer); and processing a semiconductor substrate via the patterned vapor-deposited film (spacer).

[0115] (VIII-2) The step of forming a resist underlayer film using the resist underlayer film-forming composition according to one embodiment of the present invention is as described above in [VII: Resist Underlayer Film]. A hard mask such as a silicon-containing film may be formed as a second resist underlayer film on the resist underlayer film formed by the above step, and a resist pattern may be formed thereon. This second resist underlayer film may be a coated film, or a SiON film, SiN film, or SiO film formed by a vapor deposition method such as CVD or PVD. ２The resist underlayer film may be a resist pattern forming film. Furthermore, an antireflective coating (BARC) may be formed on the second resist underlayer film as a third resist underlayer film, and the third resist underlayer film may be a resist shape correction film without antireflective properties. In the resist pattern forming process, exposure is performed through a mask (reticle) for forming a predetermined pattern or by direct writing. Examples of exposure sources that can be used include g-line, i-line, KrF excimer laser, ArF excimer laser, EUV, and electron beam. After exposure, post-exposure baking is performed as needed. The resist is then developed with a developer (e.g., a 2.38% by mass aqueous solution of tetramethylammonium hydroxide, butyl acetate), and then rinsed with a rinse solution or pure water to remove the used developer. Post-baking is then performed to dry the resist pattern and enhance adhesion to the underlying substrate. The etching process performed after the resist pattern formation is performed by dry etching. The following gases are used for processing the hard mask (silicon-containing layer), resist underlayer film, and substrate: CF ４ , CHF ３ , C.H. ２ F ２ , CH ３ F, C ４ F ６ , C ４ F ８ , O ２ , N ２ O, NO ２ , H ２ , He can be used. These gases may be used alone or in combination of two or more. Furthermore, these gases may be mixed with argon, nitrogen, carbon dioxide, carbonyl sulfide, sulfur dioxide, neon, or nitrogen trifluoride.

[0116] (VIII-3) The resist film may be patterned by a nanoimprinting method or a self-assembled film method. In the nanoimprinting method, a resist composition is molded using a patterned mold that is transparent to irradiated light. In the self-assembled film method, a pattern is formed using a self-assembled film that naturally forms a regular structure on the nanometer order, such as a diblock polymer (polystyrene-polymethyl methacrylate, etc.). In the nanoimprinting method, before applying the curable composition that will become the resist film, a silicon layer (hard mask layer) may optionally be formed on the resist underlayer film by coating or vapor deposition, and an adhesion layer may further be formed on the resist underlayer film or the silicon layer (hard mask layer) by coating or vapor deposition, and the curable composition that will become the resist film may be applied on the adhesion layer.

[0117] (VIII-4) In addition, wet etching may be performed to simplify the process steps and reduce damage to the processed substrate. This leads to suppression of fluctuations in processing dimensions and reduction of pattern roughness, making it possible to process the substrate with a high yield. Therefore, in (IVA)(iii) to (iv), the hard mask can be removed by either etching or an alkaline chemical solution. In particular, when an alkaline chemical solution is used, there are no restrictions on the components, but it is preferable that the alkaline component contains the following:

[0118] Examples of the alkaline component include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, methyltripropylammonium hydroxide, methyltributylammonium hydroxide, ethyltrimethylammonium hydroxide, dimethyldiethylammonium hydroxide, benzyltrimethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, and (2-hydroxyethyl)trimethylammonium hydroxide, monoethanolamine, diethanolamine, triethanolamine, 2-(2-aminoethoxy)ethanol, N,N-dimethylethanolamine, N,N-diethylethanolamine, N , N-dibutylethanolamine, N-methylethanolamine, N-ethylethanolamine, N-butylethanolamine, N-methyldiethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, tetrahydrofurfurylamine, N-(2-aminoethyl)piperazine, 1,8-diazabicyclo[5.4.0]undecene-7, 1,4-diazabicyclo[2.2.2]octane, hydroxyethylpiperazine, piperazine, 2-methylpiperazine, trans-2,5-dimethylpiperazine, cis-2,6-dimethylpiperazine, 2-piperidinemethanol, cyclohexylamine, 1,5-diazabicyclo[4.3.0]nonene-5, etc. Furthermore, particularly from the viewpoint of handling, tetramethylammonium hydroxide and tetraethylammonium hydroxide are particularly preferred, and an inorganic base may be used in combination with the quaternary ammonium hydroxide. As the inorganic base, alkali metal hydroxides such as potassium hydroxide, sodium hydroxide, rubidium hydroxide, etc. are preferred, with potassium hydroxide being more preferred.

[0119] [IX] The resist underlayer film-forming composition according to the present invention contains one or more bases B as an additional base component. ２ Without wishing to be bound by theory, it is believed that the addition of such a base slows down the hardening rate by trapping the acid generated during firing, resulting in the formation of SiO ２It is possible to obtain a cured film with high flatness and high embedding properties for various film types such as SiO2, TiN, and SiN. In addition, since there is no influence from the acid generator and the storage stability of the polymer, which is the main component of the resist underlayer film, can be ensured, it is possible to form a film that does not discolor or dissolve in photoresist solvents.

[0120] [Polymer Synthesis 1] Polymers used in resist underlayer films having structural formulas (S1) to (S15) were synthesized using Compound Group A, Compound Group B, Compound Group C, Catalyst Group D, Solvent Group E, and Reprecipitation Solvent Group F shown below.

[0121] ○Compound groups A to C

[0122] Catalyst group D, solvent group E, reprecipitation solvent group F p-toluenesulfonic acid monohydrate: D1 methanesulfonic acid: D2 1,4-dioxane: E1 toluene: E2 propylene glycol monomethyl ether acetate (=PGMEA): E3 methanol: F1

[0123] Synthesis Example 1: 10.0 g of phenylnaphthylamine, 7.1 g of 1-naphthaldehyde, 0.9 g of p-toluenesulfonic acid monohydrate, and 21.0 g of 1,4-dioxane were placed in a flask. The mixture was then heated to 110°C under nitrogen and reacted for approximately 12 hours. After the reaction was stopped, the mixture was reprecipitated with methanol and dried to obtain resin (S1). The weight-average molecular weight Mw measured in polystyrene equivalent terms by GPC was approximately 1,400. The resulting resin was dissolved in PGMEA, and ion exchange was carried out for 4 hours using a cation exchange resin and an anion exchange resin to obtain a solution of the target compound.

[0124] [Synthesis Examples 2 to 15] Polymers to be used for resist underlayer films were synthesized by variously changing Compound Group A, Compound Group B, Compound Group C, Catalyst Group D, Solvent Group E, and Reprecipitation Solvent Group F. The experimental procedures were the same as in Synthesis Example 1. Polymers (S1) to (S15) were obtained by synthesis under the following conditions.

[0125]

[0126] [Preparation of Resist Underlayer Film 1] Polymers (S1) to (S15), crosslinkers (CR1 to CR2), acid generators (Ad1 to Ad3), bases (Base1 to Base12, the molar ratio relative to the molar amount of acid generator is shown in parentheses), solvents (propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), cyclohexanone (CYH)), and Megafac R-40 (manufactured by DIC Corporation, G1) as a surfactant were mixed in the proportions shown in the table below, and the mixture was filtered through a 0.1 μm polytetrafluoroethylene microfilter to prepare resist underlayer film materials (M1 to M29, Comparative M1 to Comparative M18). Note that the numerical values ​​for the crosslinker, acid generator, and surfactant in the table represent the grams of crosslinker, acid generator, and surfactant used per 100 g of polymer. The numerical value of the base is expressed in parentheses because it is a molar ratio relative to the number of moles of the acid generator, as described above, and the numerical value of each solvent indicates the number of grams of each solvent used, assuming the total amount of solvent is 100 g.

[0127] The evaluations of the examples described below show the results of comparing the properties with those of comparative examples using polymers of the same synthesis examples.

[0128] [Resist Solvent Dissolution Test 1] Each resist underlayer film material was applied to a silicon wafer using a spin coater and baked on a hot plate at 240°C for 60 seconds to form a resist underlayer film with a film thickness of approximately 120 nm (Comparative Example 1-18 and Example 1-29). The formed resist underlayer film was immersed in a general-purpose thinner, PGME / PGMEA = 7 / 3, for 60 seconds, spin-dried, and baked at 100°C for 30 seconds. The film thickness before and after immersion in the thinner was compared to confirm resistance to the solvent. A film thickness reduction of 1% or less before and after immersion in the thinner was judged as ○, and a film thickness reduction of 1% or more was judged as ×.

[0129] [Storage Stability Test 1 for Resist Underlayer Film Materials] The total solids content of each resist underlayer film material was adjusted to 3% (Comparative Example 1-18 and Example 1-29). These samples were placed in screw tubes and stored in a thermostatic chamber at 35°C for one week under light-shielded conditions. After one week, the color of the sample before and after storage was visually confirmed. Cases where a color change was observed were rated as ×, and cases where no color change was observed were rated as ◯.

[0130]

[0131] [Evaluation of embedding property 1] SiO with a thickness of 200 nm ２、 The embedding ability was confirmed in a dense pattern area of ​​a SiN or TiN substrate with a trench width of 50 nm and a pitch of 100 nm. Each resist underlayer film material was applied to the substrate and then baked at 240°C for 60 seconds to form a resist underlayer film of approximately 120 nm (Comparative Example 1-20 and Example 1-31). The planarization ability of this substrate was observed using a scanning electron microscope (S-4800) manufactured by Hitachi High-Technologies Corporation, and the presence or absence of the resist underlayer film-forming composition filling the interior of the pattern was confirmed. Cases where the resist underlayer film was embedded were judged as ◯, and cases where the resist underlayer film was not embedded were judged as ×.

[0132] [Coating Test 1 on a Stepped Substrate] As a coating test on a stepped substrate, a 200 nm thick SiO ２、On SiN and TiN substrates, the coating film thickness was compared between an 800 nm trench area (TRENCH) and an open area (OPEN) where no pattern was formed. Each resist underlayer film-forming composition was applied to the substrate and then baked at 240°C for 60 seconds to form a resist underlayer film of approximately 120 nm (Comparative Example 1-20 and Example 1-31). The planarization of this substrate was observed using a scanning electron microscope (S-4800) manufactured by Hitachi High-Technologies Corporation, and the planarization was evaluated by measuring the film thickness difference between the trench area (patterned portion) and the open area (non-patterned portion) of the stepped substrate (the coating step between the trench area and the open area, referred to as bias). Here, planarization means that the difference in film thickness (Iso-dense bias) of the coated material present on the upper portion of the patterned portion (trench area (patterned portion)) and the non-patterned portion (open area (non-patterned portion)) is small. Examples showing improved bias compared to the comparative examples were evaluated as "good."

[0133] As shown in Tables 1 and 2, even when a base component is added, the composition exhibits sufficient curability as a resist underlayer film. By adding an amine component, which is more basic than pyridine, as a base, the free sulfonic acid is captured. As a result, coloration resulting from the action of sulfonic acid on a polymer containing an amine component is suppressed, and storage stability is significantly improved. Furthermore, by adding a base component, it is possible to trap a portion of the acid component generated from the acid generator in the resist underlayer film composition during baking. This allows the curing rate to be reduced, ensuring sufficient flow time for the resin, making it possible to provide a flatter film on a patterned substrate, and, depending on the resin, improving embedding properties. This effect is achieved by using SiN, SiO ２ , TiN, and other patterned substrates.

[0134] [Polymer Synthesis 2] Polymers of structural formulae (S'1) to (S'11) used for resist underlayer films were synthesized using the following compounds A', compounds B', catalysts C', solvents D', and reprecipitation solvents E'.

[0135] ○Compound group A'-B'

[0136] Catalyst group C', solvent group D', reprecipitation solvent group E' Methanesulfonic acid: C'1 Trifluoromethanesulfonic acid: C'2 Propylene glycol monomethyl ether acetate: D'1 Propylene glycol monomethyl ether: D'2 Methanol / water: E'1 Methanol: E'2

[0137] Synthesis Example 1' A flask was charged with 13.0 g of catechol, 18.4 g of 1-naphthaldehyde, 3.4 g of methanesulfonic acid, 24.4 g of propylene glycol monomethyl ether acetate, and 10.5 g of propylene glycol monomethyl ether. The mixture was then reacted under reflux conditions under nitrogen for approximately 30 hours. After the reaction was stopped, the mixture was reprecipitated in a methanol / water mixed solvent and dried to obtain resin (S'1). The weight-average molecular weight Mw measured by GPC in terms of polystyrene was approximately 1,650. The resulting resin was dissolved in PGMEA, and ion exchange was carried out for 4 hours using a cation exchange resin and an anion exchange resin to obtain a solution of the target compound.

[0138] [Synthesis Examples 2' to 11'] Polymers to be used for resist underlayer films were synthesized by varying Compound Group A', Compound Group B', Catalyst Group C', Solvent Group D', and Reprecipitation Solvent Group E'. The experimental procedures were the same as in Synthesis Example 1'. Polymers (S'1) to (S'11) were obtained by synthesis under the following conditions.

[0139]

[0140] [Preparation of Resist Underlayer Film 2] Polymers (S'1) to (S'11), crosslinkers (CR'1 to CR'3), acid generators (Ad'1 to Ad'4), bases (Base'1 to Base'12, the molar ratio relative to the number of moles of acid generator is shown in parentheses), solvents (propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), cyclohexanone (CYH)), and Megafac R-40 (manufactured by DIC Corporation, G'1) as a surfactant were mixed in the proportions shown in the table below, and the mixture was filtered through a 0.1 μm polytetrafluoroethylene microfilter to prepare resist underlayer film materials (M'1 to M'26, Comparative M'1 to Comparative M'13). In Table 4, the numerical values ​​for the crosslinker, acid generator, and surfactant represent the number of grams of the crosslinker, acid generator, and surfactant used when 100 g of polymer is used. The numerical value for the base alone is in parentheses because, as mentioned above, it is a molar ratio relative to the number of moles of the acid generator, and the standard is different. The numerical value for each solvent represents the number of grams of each solvent used when the total amount of solvent is 100 g.

[0141] The evaluations of the examples described below show the results of comparing the properties with those of comparative examples using polymers of the same synthesis examples.

[0142] [Resist Solvent Dissolution Test 2] Each resist underlayer film material was applied to a silicon wafer using a spin coater and baked on a hot plate at 240°C for 60 seconds to form a resist underlayer film with a film thickness of approximately 120 nm (Comparative Examples 1'-13' and Examples 1'-26'). The formed resist underlayer film was immersed in a general-purpose thinner, PGME / PGMEA (7 / 3), for 60 seconds, spin-dried, and baked at 100°C for 30 seconds. The film thickness before and after immersion in the thinner was compared to confirm resistance to the solvent. A film thickness reduction of 1% or less after immersion in the thinner was judged as O, and a film thickness reduction of 1% or more was judged as ×.

[0143]

[0144] [Evaluation of embedding property 2] SiO ２、 The embedding ability was confirmed in a dense pattern area of ​​a SiN or TiN substrate with a trench width of 50 nm and a pitch of 100 nm. Each resist underlayer film material was applied to the substrate and then baked at 240°C for 60 seconds to form a resist underlayer film of approximately 120 nm (Comparative Example 1'-15' and Example 1'-28'). The planarization ability of this substrate was observed using a scanning electron microscope (S-4800) manufactured by Hitachi High-Technologies Corporation, and the presence or absence of the resist underlayer film-forming composition filling the interior of the pattern was confirmed. Cases where the resist underlayer film was embedded were judged as ◯, and cases where the resist underlayer film was not embedded were judged as ×.

[0145] [Coating Test 2 on a Stepped Substrate] As a coating test on a stepped substrate, a 200 nm thick SiO ２、 On SiN and TiN substrates, the coating film thickness was compared between an 800 nm trench area (TRENCH) and an open area (OPEN) where no pattern was formed. Each resist underlayer film-forming composition was applied to the substrate and then baked at 240°C for 60 seconds to form a resist underlayer film of approximately 120 nm (Comparative Example 1'-15' and Example 1'-28'). The planarization of this substrate was observed using a scanning electron microscope (S-4800) manufactured by Hitachi High-Technologies Corporation, and the planarization was evaluated by measuring the film thickness difference between the trench area (patterned portion) and the open area (non-patterned portion) of the stepped substrate (the coating step between the trench area and the open area, referred to as bias). Here, planarization means that the difference in film thickness (Iso-dense bias) of the coating present on the upper portion of the patterned portion (trench area (patterned portion)) and the non-patterned portion (open area (non-patterned portion)) is small. Examples showing improved bias compared to the comparative examples were evaluated as "good."

[0146]

[0147] As shown in Tables 1' and 2', even when a base component is added, the resist underlayer film exhibits sufficient curability. Furthermore, by adding a base component, it is possible to trap a portion of the acid component generated from the acid generator in the resist underlayer film composition during baking. This allows the curing rate to be slowed, ensuring sufficient flow time for the resin and providing a film that is flatter and has better embedding properties on patterned substrates. This effect is due to the addition of SiN, SiO ２ , TiN, and other patterned substrates.

Claims

1. (a) The following formula (1): 【Transformation 67】 a thermal acid generator represented by the formula: (b) Polymers containing aromatic rings; (c) One or more bases B ２ and (d) solvent A resist underlayer film-forming composition comprising: In formula (1), A １ represents an optionally substituted linear, branched, or cyclic saturated or unsaturated aliphatic hydrocarbon group, or an optionally substituted aromatic ring residue, In formula (1), n ​​represents the number of sulfonate anion groups and is 1 or 2; In formula (1), B １ represents one or more counter bases, which are mono- or di- or tri-acid bases, A １ and B １ may be linked to by a single bond or a linking group, B １ and B ２ wherein at least one base has a pKa greater than that of pyridine; A resist underlayer film-forming composition.

2. 2. The resist underlayer film forming composition according to claim 1, wherein the polymer containing an aromatic ring is a novolak resin.

3. The aromatic ring-containing polymer is a novolak resin containing a unit structure having an aromatic ring which may have a substituent, and the aromatic ring is (i) a heteroatom is contained in the substituent on the aromatic ring; (ii) The unit structure contains a plurality of aromatic rings, at least two of which are linked to each other by a linking group, and the linking group contains a heteroatom; or (iii) 3. The resist underlayer film forming composition according to claim 2, wherein the aromatic ring is an aromatic heterocycle or an aromatic ring formed as a condensed ring with one or more heterocycles.

4. 4. The resist underlayer film forming composition according to claim 3, wherein the unit structure (i) or (ii) is a unit structure having an aromatic ring having at least one oxygen-containing substituent, or an aromatic ring connected by at least one —NH—.

5. The polymer containing an aromatic ring is (i) one or more unit structures having an aromatic ring which may have a substituent; and (ii) A novolak resin having a unit structure containing an organic group which is a 4- to 17-membered monocyclic, bicyclic, tricyclic, or tetracyclic organic group which may have a substituent, wherein the monocyclic group is a non-aromatic monocyclic group; at least one of the monocyclic groups constituting the bicyclic, tricyclic, or tetracyclic group is a non-aromatic monocyclic group, and the remaining monocyclic groups may be either aromatic or non-aromatic monocyclic groups; The monocyclic, bicyclic, tricyclic, or tetracyclic organic group may further be fused with one or more aromatic rings to form a pentacyclic or higher ring; (i) and (ii) are bonded by a covalent bond between at least a carbon atom on the non-aromatic monocyclic ring of (ii) and a carbon atom on the aromatic ring of (i); The resist underlayer film forming composition according to claim 2 .

6. The aromatic ring-containing polymer is represented by the following formula (AB): 【Transformation 68】 The compound includes a structure represented by In formula (AB), n represents the number of composite unit structures A-B. The unit structure A is One or more unit structures having an aromatic ring which may have a substituent, The substituents may contain heteroatoms, The unit structure contains a plurality of aromatic rings, the plurality of aromatic rings are connected to each other via linking groups, and the linking groups may contain a heteroatom, The aromatic ring may be an aromatic heterocycle, or may be an aromatic ring formed as a condensed ring with one or more heterocycles; The unit structure B represents one or more unit structures including a structure represented by the following formula (B1), (B2), or (B3): The resist underlayer film forming composition according to claim 2 . 【Transformation 69】 [In formula (B1), R and R′ each independently represent a hydrogen atom, an aromatic ring residue having 6 to 30 carbon atoms which may have a substituent, a heterocyclic ring residue having 3 to 30 carbon atoms which may have a substituent, or a linear, branched, or cyclic alkyl group having 10 or less carbon atoms which may have a substituent.] 【Transformation 70】 [In formula (B2), Z ０ represents an aromatic ring residue or an aliphatic ring residue having 6 to 30 carbon atoms, which may have a substituent, or an organic group in which two aromatic ring residues or aliphatic ring residues are linked by a single bond; J １ and J ２ each independently represents a direct bond or a divalent organic group which may have a substituent. 【Chemistry 71】 [In formula (B3), Z is a monocyclic, bicyclic, tricyclic or tetracyclic fused ring having 4 to 25 carbon atoms which may have a substituent, and the monocyclic ring is a non-aromatic monocyclic ring; at least one of the monocyclic rings constituting the bicyclic, tricyclic or tetracyclic ring is a non-aromatic monocyclic ring, and the remaining monocyclic rings may be aromatic or non-aromatic monocyclic rings; the monocyclic, bicyclic, tricyclic or tetracyclic fused ring may further form a fused ring with one or more aromatic rings to form a pentacyclic or higher fused ring; X and Y may be the same or different and each represent -CR 31 R 32 represents a - group, and R 31 and R 32 are the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, x and y represent the number of X and Y, respectively, and each independently represents 0 or 1; 【Chemistry 72】 is bonded to any carbon atom (referred to as "carbon atom 1") constituting the non-aromatic monocyclic ring of Z (when x = 1) or extends from carbon atom 1 (when x = 0), 【Transformation 73】 is bonded to any carbon atom (referred to as "carbon atom 2") constituting the non-aromatic monocyclic ring of Z (when y = 1) or extends from carbon atom 2 (when y = 0), the carbon atom 1 and the carbon atom 2 may be the same or different, and when they are different, they may belong to the same non-aromatic monocycle or different non-aromatic monocycles; * indicates a bond.

7. The formula (B3) is the following formula (B31): 【Chemistry 74】 [In formula (B31), Z is a 4- to 17-membered monocyclic, bicyclic, tricyclic, or tetracyclic organic group which may have a substituent, and the monocyclic group is a non-aromatic monocyclic group; at least one of the monocyclic groups constituting the bicyclic, tricyclic, or tetracyclic group is a non-aromatic monocyclic group, and the remaining monocyclic groups may be either aromatic or non-aromatic monocyclic groups; The monocyclic, bicyclic, tricyclic, or tetracyclic organic group may further be fused with one or more aromatic rings to form a pentacyclic or higher ring; C and C' each represent one carbon atom in the group of atoms constituting the cyclic moiety of any of the non-aromatic monocycles represented by Z, and the non-aromatic monocycles to which C and C' belong may be the same or different; n is the number of carbon atoms C′ and represents an integer of 0 to 2; p, q, p', and q' represent the number of bonds, each independently representing 0 or 1; when n is 0, p and q are 1; When n is 1 or 2, at least one of p and q, and at least one of p' and q' of each C' are each 1; when n is 2, the non-aromatic monocycles to which the two C's belong may be the same or different, and when they are the same, the two C's may or may not be directly bonded to each other; X, Y, X', and Y' may be the same or different and each represent -CR 1 R 2 represents a - group, and R 1 and R 2 are the same or different and each represent a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, when n is 2, two X' may be the same or different, and two Y' may be the same or different, x, y, x', and y' represent the numbers X, Y, X', and Y', respectively, and each independently represents 0 or 1.] The resist underlayer film forming composition according to claim 6 , wherein the resist underlayer film forming composition is represented by the formula:

8. The sulfonate anion group (SO ) contained in the thermal acid generator (a) ３ － When the amount of base required to neutralize the same number of moles of sulfonic acid (monobasic acid) as that of component (a) is taken as 1 equivalent, the counter base B in formula (i) of component (a) is １ and the base B of component (c) ２ 2. The resist underlayer film forming composition according to claim 1, wherein the base having a pKa greater than that of pyridine is present in an amount of 1.05 equivalents or greater.

9. The sulfonate anion group (SO ) contained in the thermal acid generator (a) ３ － When the amount of base required to neutralize the same number of moles of sulfonic acid (monobasic acid) as the base B is taken as 1 equivalent, ２ 2. The resist underlayer film forming composition according to claim 1, wherein the amount of added is 0.05 to 3.0 equivalents.

10. Counterbase B in formula (1) of component (a) １ and / or the base B of component (c) ２ is R I R II R III N, R I and R II each independently represents a hydrogen atom or an optionally substituted linear or branched saturated or unsaturated aliphatic hydrocarbon group, R I and R II may form a ring via a heteroatom or without a heteroatom, or may form a ring via an aromatic ring, R III represents a hydrogen atom, an optionally substituted aromatic ring residue, or an optionally substituted linear or branched saturated or unsaturated aliphatic hydrocarbon group, R I and R II does not form a ring, R III is a hydrogen atom or an optionally substituted aromatic ring residue, The resist underlayer film forming composition according to claim 1 .

11. Counterbase B in formula (1) of component (a) １ and / or the base B of component (c) ２ teeth, 【Chemistry 75】 [In the formula, R １ and R ２ each independently represents an optionally substituted linear or branched, saturated or unsaturated aliphatic hydrocarbon group, R ３ represents a hydrogen atom or an optionally substituted aromatic hydrocarbon group; or A cyclic amine compound represented by the following formula (III): 【Transformation 76】 [In formula (3), R is hydrogen atom; a nitro group, a cyano group, an amino group, a carboxyl group, a hydroxy group, an amide group, an aldehyde group, a (meth)acryloyl group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, an organic group containing an ether bond, an organic group containing a ketone bond, or an organic group containing an ester bond, which may be substituted with a halogen atom or an alkoxy group having 1 to 10 carbon atoms; or It is a group that combines them, R' is an aromatic ring fused with the ring of the cyclic amine in formula (3), or 【Chemical 77】 and R ａ and R ｂ each independently represents an optionally substituted alkylene group; X is O, S, SO ２ , CO, CONH, COO, or NH; n and m are each independently 2, 3, 4, 5, or 6. The resist underlayer film forming composition according to claim 1 , wherein the base is represented by the formula:

12. R in the above formula (2) ３ represents an optionally substituted phenyl, naphthyl, anthracenyl, pyrenyl, or phenanthrenyl group, R in the above formula (3) is a hydrogen atom, a methyl group, an ethyl group, an isobutyl group, an allyl group, or a cyanomethyl group; R' in the above formula (3) is 【Transformation 78】 and n and m each independently represent 2, 3, 4, 5, or 6.

13. Counterbase B in formula (1) of component (a) １ and / or the base B of component (c) ２ 2. The resist underlayer film forming composition according to claim 1, wherein is one or more of N-methylmorpholine, N-isobutylmorpholine, N-allylmorpholine, and N,N-diethylaniline.

14. A in the above formula (1) １ 2. The resist underlayer film forming composition according to claim 1, wherein is a methyl group, a trifluoromethyl group, a naphthyl group, a norbornanylmethyl group, a dimethylphenyl group, or a tolyl group.

15. The resist underlayer film forming composition according to claim 1 , further comprising a crosslinking agent.

16. The resist underlayer film forming composition according to claim 15, wherein the crosslinking agent is an aminoplast crosslinking agent or a phenoplast crosslinking agent.

17. 17. The resist underlayer film forming composition according to claim 16, wherein the aminoplast crosslinker is a highly alkylated, alkoxylated, or alkoxyalkylated melamine, benzoguanamine, glycoluril, urea, or polymer thereof.

18. 17. The resist underlayer film forming composition according to claim 16, wherein the phenoplast crosslinker is a highly alkylated, alkoxylated, or alkoxyalkylated aromatic, or a polymer thereof.

19. 2. The resist underlayer film forming composition according to claim 1, wherein the solvent (d) is a compound having an alcoholic hydroxyl group or a compound having a group capable of forming an alcoholic hydroxyl group.

20. 20. The resist underlayer film forming composition according to claim 19, wherein the compound having an alcoholic hydroxyl group or the compound having a group capable of forming an alcoholic hydroxyl group is a propylene glycol-based solvent, an oxyisobutyric acid ester-based solvent, or a butylene glycol-based solvent.

21. 20. The resist underlayer film forming composition according to claim 19, wherein the compound having an alcoholic hydroxyl group or the compound having a group capable of forming an alcoholic hydroxyl group is propylene glycol monomethyl ether, methyl 2-hydroxy-2-methylpropionate, cyclohexanone, propylene glycol monomethyl ether acetate, or ethyl lactate.

22. The resist underlayer film forming composition according to claim 1 , further comprising a surfactant.

23. A resist underlayer film, which is a baked product of a coating film comprising the resist underlayer film-forming composition according to any one of claims 1 to 22, formed on a semiconductor substrate.

24. A method for forming a resist pattern used in the production of semiconductors, comprising the step of applying the resist underlayer film-forming composition according to any one of claims 1 to 22 onto a semiconductor substrate and baking the composition to form a resist underlayer film.

25. A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of claims 1 to 22; forming a resist film thereon; a step of forming a resist pattern by irradiating with light or an electron beam and developing; Etching the resist underlayer film using the formed resist pattern; and A process for processing a semiconductor substrate using a patterned resist underlayer film. A method for manufacturing a semiconductor device comprising:

26. A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of claims 1 to 22; forming a hard mask thereon; a step of forming a resist film thereon; a step of forming a resist pattern by irradiating with light or an electron beam and developing; Etching the hard mask using the formed resist pattern; Etching the resist underlayer film with a patterned hard mask; and A process for processing a semiconductor substrate using a patterned resist underlayer film. A method for manufacturing a semiconductor device comprising:

27. A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of claims 1 to 22; forming a hard mask thereon; a step of forming a resist film thereon; a step of forming a resist pattern by irradiating with light or an electron beam and developing; Etching the hard mask using the formed resist pattern; Etching the resist underlayer film with a patterned hard mask; removing the hard mask; and A process for processing a semiconductor substrate using a patterned resist underlayer film. A method for manufacturing a semiconductor device comprising:

28. A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of claims 1 to 22; forming a hard mask thereon; a step of forming a resist film thereon; a step of forming a resist pattern by irradiating with light or an electron beam and developing; Etching the hard mask using the formed resist pattern; Etching the resist underlayer film with a patterned hard mask; removing the hard mask; and forming a vapor-deposited film (spacer) on the resist underlayer film after removing the hard mask; A process of processing the vapor-deposited film (spacer) by etching; removing the patterned resist underlayer film to leave a patterned vapor-deposited film (spacer); and A method for manufacturing a semiconductor device, comprising: processing a semiconductor substrate through a patterned vapor-deposited film (spacer).

29. The manufacturing method according to claim 26, wherein the hard mask is formed by coating or vapor deposition of an inorganic substance.

30. The manufacturing method according to claim 25, wherein the resist film is patterned by a nanoimprint method or a self-assembled film.

31. 28. The method for manufacturing a semiconductor device according to claim 27, wherein the hard mask is removed by etching or an alkaline chemical solution.

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