Resist underlayer film forming composition, and resist pattern formation method and semiconductor device manufacturing method using said composition

Abstract

Provided is a resist underlayer film forming composition that satisfies not only characteristics such as etching resistance and heat resistance but also satisfies various other characteristics such as curability, amount of generated sublimates, flattening characteristics, and optical characteristics (suppression of reflection when being exposed).　This resist underlayer film forming composition contains a novolak resin and a solvent. The novolak resin includes a unit structure A having an aromatic ring. The unit structure A includes one or more structural units represented by formula (A). R1 represents a hydrogen atom or a specific substituent group. R2 represents an arbitrarily selected specific substituent group. At least a portion of R1 and R2 in the novolak resin is a substituent group that has an alkynyl chain having 2-10 carbon atoms, and n represents the number of substituent groups R2. When n is more than one, the plurality of R2 may be the same or different from each other. '*' indicates a bond.

Description

[Rule 26 Supplement 10.08.2023] Resist underlayer film forming composition, method for forming a resist pattern using said composition, and method for manufacturing a semiconductor device

[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, the semiconductor manufacturing process has progressed rapidly, and this has led to a strong demand for higher quality and improved properties of resist underlayer films.

[0003] For example, Patent Document 1 reports that a polymer containing, as structural units, a divalent group of a specific heteroaromatic ring containing an indole skeleton as part of its structure and an aryl-substituted divalent group such as an aryl-substituted methylene group can be used as a material that achieves both film density and etching resistance. However, although the planarization property is mentioned, no demonstration has been provided.

[0004] Furthermore, Patent Document 2 reports that a polymer obtained by reacting an indole derivative with a mixture of specific types of aromatic aldehyde compounds can simultaneously ensure the solubility (applicability) of the polymer and the etching resistance and heat resistance of a hard mask layer using the polymer.

[0005] Furthermore, it has been reported that a resist underlayer film-forming composition containing a 2-arylindole derivative / analog structure and a polymer having an aryl-substituted methylene group as a unit structure in Patent Document 3, and a resist underlayer film-forming composition containing a pyrrole novolak resin in Patent Document 4, can form a good resist pattern shape without causing intermixing between the upper layer of the resist underlayer film and the layer coated thereon. Heat resistance is also mentioned, but has not been proven.

[0006] The novolak resins having an indole structure described in Patent Documents 1 to 3 have excellent etching resistance and heat resistance, but their optical constants are significantly different from those generally used for antireflection. Furthermore, they also have problems with planarization. On the other hand, the novolak resin having a pyrrole novolak structure described in Patent Document 4 exhibits a high refractive index / low absorption coefficient suitable for antireflection, but when various properties necessary for improving the quality and properties of resist underlayer films, such as curability, curing speed, film shrinkage, heat resistance, coatability on uneven substrates, planarization, embeddability, amount of sublimation product, etching resistance, and optical constants, are taken into consideration, there is still room for improvement.

[0007] JP 2016-151024 A JP 2020-105513 A International Publication No. 2013 / 146670 (A1) International Publication No. 2014 / 208499 (A1)

[0008] Therefore, the problem to be solved by the present invention is to provide a resist underlayer film-forming composition that satisfies the requirements for curability, suppression of the amount of sublimation product generated, and planarization properties in addition to etching resistance and heat resistance, and that also favorably maintains other properties such as coatability on uneven substrates having various vapor-deposited films, embeddability, and optical properties (suppression of reflection during exposure); 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.

[0009] The present invention includes the following aspects.

[0010] [1] A resist underlayer film-forming composition comprising a novolac resin and a solvent, wherein the novolac resin comprises a unit structure A having an aromatic ring, and the unit structure A is represented by the following formula (A): In the formula (A), R １ represents a hydrogen atom or a substituent on a nitrogen atom of a pyrrole ring, the substituent being (i) a methylol group; (ii) a linear, branched or cyclic alkoxymethyl group having 2 to 20 carbon atoms; or (iii) a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 30 carbon atoms; R ２represents an optional substituent on a carbon atom constituting a pyrrole ring, and is (iv); the same group of substituents as in (iii); or (v) an acyl group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, an aryloxy group having 6 to 15 carbon atoms, an alkoxycarbonyl group having 1 to 15 carbon atoms, an aryloxycarbonyl group having 7 to 15 carbon atoms, a mono-substituted amino group having 1 to 15 carbon atoms, or a di-substituted amino group having 2 to 30 carbon atoms; (vi) a hydroxy group, a nitro group, an amino group, a cyano group, a carboxyl group, a trifluoromethyl group, or a halo group, with the proviso that (ii) to (v) may be further substituted with an oxygen-atom-containing substituent, a sulfur-atom-containing substituent, a nitrogen-atom-containing substituent, an aryl group, or a halo group, or the hydrocarbon chain portion may be further interrupted by an oxygen-atom-containing substituent, a sulfur-atom-containing substituent, a nitrogen-atom-containing substituent, or an arylene group, and R in the novolak resin １ and R ２ At least a part of the substituents R ２ When n is plural, it represents the number of R ２ may be the same or different, and * indicates a bond.

[0011] [2] The novolak resin is represented by the following formula (AB): The resist underlayer film-forming composition according to [1], comprising a composite unit structure A-B represented by the following formula (AB): [In formula (B1), R １１ and R １２ each independently represents 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, and * indicates a bond.] [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, １ and J ２ each independently represents a direct bond or a divalent organic group which may have a substituent, and * indicates a bond. [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 numbers 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 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 if different, they may belong to the same non-aromatic monocycle or different non-aromatic monocycles, and * indicates a bond.]

[0012] [3] R in novolac resin １ and R ２ wherein the alkynyl chain is of the formula: [where * indicates a bond, R ３ is a single bond or a divalent organic group having 1 to 7 carbon atoms, R４ is a hydrogen atom or a monovalent organic group having 1 to 7 carbon atoms, and R ３ and R ４ The resist underlayer film forming composition according to [1] or [2], wherein the total number of carbon atoms is 0 to 8.

[0013] [4] The resist underlayer film forming composition according to any one of [1] to [3], wherein the solvent includes a solvent having a boiling point of 160° C. or higher.

[0014] [5] The resist underlayer film-forming composition according to any one of [1] to [4], further comprising an acid and / or a salt thereof and / or an acid generator.

[0015] [6] The resist underlayer film-forming composition according to any one of [1] to [5], further comprising a crosslinking agent.

[0016] [7] The resist underlayer film-forming composition according to [6], wherein the crosslinking agent is an aminoplast crosslinking agent or a phenoplast crosslinking agent.

[0017] [8] The resist underlayer film forming composition according to any one of [1] to [7], further comprising a surfactant.

[0018] [9] A resist underlayer film on a semiconductor substrate, which is a baked product of a coating film comprising the resist underlayer film-forming composition according to any one of [1] to [8].

[0019]

[10] A method for forming a resist pattern used in the production of semiconductors, comprising a step of applying the resist underlayer film-forming composition according to any one of [1] to [8] onto a semiconductor substrate and baking the composition to form a resist underlayer film.

[0020]

[11] A method for manufacturing a semiconductor device, comprising: a step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of [1] to [8]; a step of forming a resist film on the resist underlayer film; a step of forming a resist pattern on the resist film by irradiating with light or an electron beam and developing; a step of etching the resist underlayer film through the resist pattern; and a step of processing a semiconductor substrate using the patterned resist underlayer film.

[0021]

[12] A method for manufacturing a semiconductor device, comprising: a step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of [1] to [8]; a step of forming a hard mask on the resist underlayer film; a step of further forming a resist film on the hard mask; a step of forming a resist pattern on the resist film by irradiating with light or an electron beam and developing; a step of etching the hard mask through the resist pattern; a step of etching the resist underlayer film through the patterned hard mask; and a step of processing a semiconductor substrate through the patterned resist underlayer film.

[0022]

[13] A method for manufacturing a semiconductor device, comprising: a step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of [1] to [8]; a step of forming a hard mask on the resist underlayer film; a step of further forming a resist film on the hard mask; a step of forming a resist pattern on the resist film by irradiating with light or an electron beam and developing; a step of etching the hard mask through the resist pattern; a step of etching the resist underlayer film through the patterned hard mask; a step of removing the hard mask; and a step of processing a semiconductor substrate through the patterned resist underlayer film.

[0023]

[14] A method for manufacturing a semiconductor device, comprising: a step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of items [1] to [8]; a step of forming a hard mask on the resist underlayer film; a step of further forming a resist film on the hard mask; a step of forming a resist pattern on the resist film by irradiating with light or an electron beam and developing; a step of etching the hard mask through the resist pattern; a step of etching the resist underlayer film through the etched hard mask; a step of removing the hard mask; a step of forming a vapor-deposited film (spacer) on the resist underlayer film after removing the hard mask; a step of processing the vapor-deposited film (spacer) by etching; a step of removing the patterned resist underlayer film to leave the patterned vapor-deposited film (spacer); and a step of processing a semiconductor substrate through the patterned vapor-deposited film (spacer).

[0024]

[15] The method for manufacturing a semiconductor device according to any one of

[12] to

[14] , wherein the hard mask is formed by coating or vapor deposition of an inorganic substance.

[0025]

[16] The method for manufacturing a semiconductor device according to any one of

[11] to

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

[0026]

[17] The method for manufacturing a semiconductor device according to any one of

[13] to

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

[0027] The novolac resin contained in the resist underlayer film composition of one embodiment of the present invention contains a pyrrole structural unit having an alkynyl group (a carbon-carbon triple bond structure, a propargyl group, or the like), and since it cures at a lower temperature than pyrrole novolac resins not having an alkynyl group, it is possible to suppress the generation of sublimate components.

[0028] On the other hand, in the case of novolac resins that begin to cure at low temperatures, it has been found that they generally increase the film shrinkage rate due to heat and impair flattening and embedding properties, and it has been difficult to achieve both of these properties and low-temperature curing properties. However, the resist underlayer film of the present invention can achieve both of the above properties by introducing an alkynyl group.

[0029] Furthermore, due to its small film shrinkage rate, it is believed to have high heat resistance and contain few sublimation components, and has good coatability to silicon wafers and various types of uneven substrates, not only when fired at low temperatures but also when fired at high temperatures.

[0030] Furthermore, because the polymer exhibits self-crosslinking properties without the need for a crosslinking agent or curing catalyst, it can be cured sufficiently even in a nitrogen atmosphere. Therefore, it can be cured sufficiently in both air, as in conventional applications, and in a nitrogen atmosphere, making it suitable for a wide range of semiconductor manufacturing processes.

[0031] Furthermore, in order to suppress reflection during exposure, materials that exhibit high n / low k optical constants at 193 nm are generally required, and the introduction of alkynyl groups can also maintain such optical properties well.

[0032] In addition to possessing the above-mentioned properties, the etching resistance can also be adjusted depending on the process, making it possible to form a good pattern shape.

[0033] [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.

[0034] (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 (such as a substitution reaction, an addition reaction, or an addition-condensation reaction) 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).

[0035] Therefore, the novolac resin referred to in this specification is a polymer formed by linking a plurality of compounds having 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.

[0036] 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.

[0037] (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.

[0038] (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).

[0039] 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, more typically aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and pyrene; and aromatic hydrocarbon rings such as furan, pyran, thiophene, pyrrole, N-alkylpyrrole, and N-arylpyrrole. Examples of aromatic heterocycles include, but are not limited to, aromatic heterocycles such as pyrrole, imidazole, pyridine, pyrimidine, pyrazine, triazine, thiazole, indole, phenylindole, bisindolefluorene, bisindolebenzofluorene, bisindoledibenzofluorene, purine, quinoline, isoquinoline, chromene, thianthrene, phenothiazine, phenoxazine, xanthene, acridine, phenazine, carbazole, and indolocarbazole, and more typically, furan, thiophene, pyrrole, indole, phenylindole, bisindolefluorene, phenothiazine, carbazole, indolocarbazole, imidazole, pyran, pyridine, pyrimidine, and pyrazine.

[0040] 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) (including an alkyl group, an alkenyl group, an alkynyl group, a propargyl group, etc., whose hydrocarbon chain may be interrupted one or more times by an oxygen atom), 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), 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 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) above; organic groups having an ether bond, such as a methoxy group, an ethoxy group, or a phenoxy group; and aryl groups.

[0041] 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.

[0042] 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.

[0043] (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.

[0044] (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.

[0045] Examples of non-aromatic monocyclic rings (aliphatic rings, aliphatic monocyclic rings) include cyclopropane, cyclobutane, cyclobutene, cyclopentane, cyclopentene, cyclohexane, methylcyclohexane, cyclohexene, methylcyclohexene, cycloheptane, and cycloheptene.

[0046] "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.

[0047] "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.

[0048] 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.

[0049] 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.

[0050] (1-6) 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) that does not have a substituent.

[0051] (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.

[0052] (1-8) In the chemical structural formula showing the unit structure of the novolac 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.

[0053] [II: Resist Underlayer Film Forming Composition] The resist underlayer film forming composition, which is one embodiment of the present invention, contains a specific novolak resin and a solvent.

[0054] (IIA) Novolak Resin (IIA-1) The specific novolak resin contained in the resist underlayer film-forming composition of one embodiment of the present invention includes a unit structure A having an aromatic ring, and the unit structure A is represented by the following formula (A): The compound contains one or more pyrrole structural units represented by the following formula:

[0055] Unless otherwise specified, hereinafter in this specification, * indicates a bond.

[0056] In the above formula (A), the bond indicated by * extends from any of the carbon atoms constituting the pyrrole ring.

[0057] (IIA-1-1) R １ is a hydrogen atom or a substituent on the nitrogen atom of the pyrrole ring.

[0058] When R is such a substituent, １ represents (i) a methylol group; (ii) a linear, branched or cyclic alkoxymethyl group having 2 to 20 carbon atoms; or (iii) a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 30 carbon atoms.

[0059] However, the substituent groups (ii) and (iii) may be further substituted with a specific substituent or the hydrocarbon chain portion may be further interrupted by a specific divalent functional group, as described in (IIA-1-4) below.

[0060] (IIA-1-2) R ２is an optional substituent on a carbon atom constituting a pyrrole ring, (iv); the same group of substituents as in (iii) above, i.e., a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 30 carbon atoms; (v) an acyl group having 1 to 15 carbon atoms (such as an acetyl group or a benzoyl group), an alkoxy group having 1 to 15 carbon atoms (such as a methoxy group or a propargyloxy group), an aryloxy group having 6 to 15 carbon atoms (such as a phenoxy group), an alkoxycarbonyl group having 1 to 15 carbon atoms (such as a methoxycarbonyl group or a propargyloxycarbonyl group), an aryloxycarbonyl group having 7 to 15 carbon atoms (such as a phenoxycarbonyl group), a mono-substituted amino group having 1 to 15 carbon atoms (such as a monoalkylamine such as a monomethylamino group, a mono(alkenyl or alkynyl)amine such as a monopropargylamino group, or a monoarylamino group such as a phenylamino group), or a di-substituted amino group having 2 to 30 carbon atoms (such as a dialkylamino group such as a dimethylamino group, or a di(alkenyl or alkynyl)amino group such as a dipropargylamino group); or (vi) a hydroxy group, a nitro group, an amino group, a cyano group, a carboxyl group, a trifluoromethyl group, or a halo group.

[0061] However, the substituent groups (iv) and (v) may be further substituted with a specific substituent or the hydrocarbon chain portion may be further interrupted by a specific divalent functional group, as described in (IIA-1-4) below. For example, an arylalkoxy group such as a benzyloxy group belongs to the substituent group (v) as an alkoxy group substituted with a phenyl group, which is an aryl group.

[0062] In formula (A), n represents a substituent R ２ When n is plural, it represents the number of R ２ When the pyrrole structural unit is present in the polymer chain, n is an integer of 0 to 2, but when the pyrrole structural unit is present at the end of the polymer chain, n may be an integer of 0 to 3.

[0063] (IIA-1-3) However, R in the novolak resin １ and R２ At least some of the groups are substituents having an alkynyl chain having 2 to 10 carbon atoms.

[0064] Here, the substituent having an alkynyl chain includes not only an alkynyl group which is an alkynyl chain itself, but also a functional group which contains an alkynyl chain as a partial structure.

[0065] More specifically, R in the novolac resin １ At least some of R are alkynyl groups having 2 to 10 carbon atoms, and / or ２ When R ２ At least a part of these may be an alkynyl group having 2 to 10 carbon atoms, an alkynyloxy group having 2 to 10 carbon atoms, an alkynyloxycarbonyl group having 3 to 11 carbon atoms, a monoalkynylamino group having 2 to 10 carbon atoms, or a di(alkynyl)amino group having 4 to 20 carbon atoms.

[0066] Among these, R in the novolac resin １ It is more preferable that at least a part of the groups be alkynyl groups having 2 to 10 carbon atoms.

[0067] However, these substituent groups may be further substituted with specific substituents or the hydrocarbon chain portion may be further interrupted by specific divalent functional groups, as will be explained in (IIA-1-4) below.

[0068] Here, R in the novolac resin １ and R ２ "At least a portion" of the group refers to the optional substituent R ２ If does not exist, then R １ and the optional substituent R ２ If present, R １ At least a part of R ２ or at least a part of R １ and at least a part of R ２ means at least a part of

[0069] The introduction rate of the alkynyl chains into the novolac resin according to one embodiment of the present invention is preferably 5% or more. The introduction rate here represents the number (%) of alkynyl chains introduced into the pyrrole structural units in the novolac resin, assuming that the number of pyrrole structural units in formula (A) is 100. Such an introduction rate can be, for example, １ H-NMR measurement １３ The introduction rate can be calculated by C-NMR. If necessary, the introduction rate may be calculated using an internal standard or the like.

[0070] The alkynyl chain may also be of the general formula: is preferable from the viewpoint of self-crosslinking property.

[0071] Here, R ３ is a single bond; or a divalent organic group having 1 to 7 carbon atoms, preferably an alkylene group, more preferably a methylene group; R ４ is a hydrogen atom or a monovalent organic group having 1 to 7 carbon atoms, preferably an alkyl group, more preferably a hydrogen atom; R ３ and R ４ The total number of carbon atoms is 0 to 8, and more preferably 1 to 3. Here, the organic group refers to a hydrocarbon group which may be further substituted with a substituent containing a heteroatom, and the hydrocarbon chain portion may be further interrupted by a divalent group containing a heteroatom [see, for example, (IIA-1-4)].

[0072] The introduction of the alkynyl chain into the pyrrole ring structural unit represented by formula (A) can be carried out by any known and conventional method. For example, after the novolak resin is produced, the alkynyl chain may be introduced using an alkynylating agent such as an alkynyl halide. Alternatively, a similar resin can be produced by preparing a monomer into which an alkynyl group has been introduced and synthesizing the novolak resin using the monomer.

[0073] (IIA-1-4) The substituent groups (ii) and (iii) in (IIA-1-1) and (iv) and (v) in (IIA-1-2) may be further substituted with an oxygen atom-containing substituent (such as a hydroxyl group, an alkoxy group, an alkoxyalkyl group, an alkoxycarbonyl group, an aryloxy group, or a carboxyl group), a sulfur atom-containing substituent (such as a sulfonic acid group, an alkylsulfide group, an arylsulfide group, an alkylsulfonyl group, or an arylsulfonyl group), a nitrogen atom-containing substituent [such as an amino group, a substituted amino group (a mono- or di-substituted amino group such as a monoalkylamine or a dialkylamine), an amido group, a cyano group, or a nitro group], an aryl group (preferably an aryl group having 6 to 20 carbon atoms, such as a phenyl group or a pyrenyl group), or a halo group.

[0074] The substituent groups (ii) and (iii) in (IIA-1-1) and (iv) and (v) in (IIA-1-2) include oxygen atom-containing substituents [divalent groups such as —O—, —C(O)—, —C(O)O—, and —OC(O)—], sulfur atom-containing substituents (—S—, —SO ２ The hydrocarbon chain portion may be further interrupted by a nitrogen atom-containing substituent [a divalent group such as —N(R)C(O)—, —C(O)N(R)—, —OC(O)N(R)—, —N(R)C(O)O—, —N(R)C(O)N(R)—, —NR—, where each R is independently the same or different and represents a hydrocarbon group having 1 to 30 carbon atoms] or an arylene group (such as a phenylene group).

[0075] The term "hydrocarbon chain moiety" as used herein refers to a linear (straight or branched) hydrocarbon moiety, such as an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, and the linear hydrocarbon moiety in an alkoxycarbonyl group having 1 to 15 carbon atoms, an alkyloxy group having 1 to 15 carbon atoms, an acyl group having 1 to 15 carbon atoms, a monoalkylamino group having 1 to 15 carbon atoms, and a dialkylamino group having 2 to 30 carbon atoms. -O-, -S-, -C(O)-, etc. are inserted between two carbon atoms in the linear hydrocarbon moiety that are single-bonded to each other (but that are not part of a cyclic structure), and therefore, at least one pair of two carbon atoms that are single-bonded to each other (carbon atoms that are not part of a cyclic structure) is present in the linear hydrocarbon moiety. For example, an alkenyl group as a whole constitutes a hydrocarbon chain moiety, but a group that contains at least one pair of two carbon atoms that are single-bonded to each other (CH ３ -CH ２ -CH ２ If a pentyl group (a - moiety) is present, it can be interrupted by a divalent group. It can refer to a part of the substituent (a pentyl group), such as in the monopentylamino group, pentylcyclohexyl group, or p-pentylphenyl group. On the other hand, the entire substituent can be a chain hydrocarbon moiety, such as in a linear or branched alkyl group.

[0076] (IIA-1-5) Novolak resins having an alkynylated pyrrole structure form resist underlayer films that exhibit better properties than conventional novolak resins having a non-alkynylated pyrrole structure. Specifically, these properties are as follows:

[0077] By introducing an alkynyl self-crosslinking group such as a propargyl group, the material can be used as a resist underlayer film not only in air but also in a nitrogen atmosphere (where curing by oxidation does not occur due to the absence of oxygen) without the need for a crosslinking agent or curing catalyst, making it applicable to a wider range of processes than conventional materials.

[0078] Furthermore, by starting curing at a low temperature, it is possible to suppress the formation of sublimate components, and yet despite curing at a low temperature, it has the characteristic of having a small film shrinkage rate (i.e., high heat resistance). This is thought to be due to the fact that the film density increases and heat resistance improves due to the formation of a three-dimensional crosslinked structure by the alkynyl self-crosslinking group, and the fact that the crosslinked structure formed by the alkynyl self-crosslinking group expands in molecular volume.

[0079] Furthermore, although the curing rate is increased, in the case of N-alkynylation, the effect of suppressing the increase in viscosity due to polarity derived from NH and the effect of lowering the polymer Tg are exhibited, and the flattening property is improved while maintaining good coatability on uneven substrates. Therefore, in the pyrrole ring structural unit of formula (A), R １ is preferably alkynylated (ie, N-alkynylated).

[0080] The embeddability is not impaired by alkynylation and exhibits good properties.

[0081] The alkynylated pyrrole structure not only exhibits the excellent properties described above, but also has the characteristic of being able to maintain the excellent optical constants of conventional pyrrole polymers (high n / low k@193 nm, preferably n value ≧ 1.3 / k value ≦ 0.7).

[0082] Although the presence of an alkynylated pyrrole structure is a necessary condition, by producing novolak resins using a wide variety of pyrrole raw materials, phenol raw materials, amine raw materials, aldehyde raw materials, ketone raw materials, and aldehyde equivalent raw materials, it is possible to freely change the optical constants and etching resistance while maintaining the above properties, and to tailor the resist underlayer film to suit the process.

[0083] These properties are not impaired by the addition of crosslinkers or acid catalysts. Therefore, novolak resins with alkynylated pyrrole structures are expected to become materials with wide applicability to diverse semiconductor manufacturing processes.

[0084] (IIA-1-6) Specific examples of the pyrrole ring structural unit represented by the representative formula (A) are listed below, where the bond from the structural unit is omitted.

[0085] Furthermore, the novolak resin contained in the resist underlayer film-forming composition, which is one embodiment of the present invention, at least partially contains pyrrole ring structural units having an alkynyl chain, such as those listed in the following specific examples (i) to (iii), but may also contain pyrrole ring structural units without an alkynyl chain, such as those listed in the following (iv).

[0086] (i) R in formula (A) １ Examples of compounds containing alkynyl chains (ii) R in formula (A) ２ Examples of compounds containing alkynyl chains (iii) R in formula (A) １ and R ２ Examples where both contain alkynyl chains (iv) Other specific examples In each of the pyrrole ring structural units listed in (i) above, specific examples in which the substituent on the nitrogen atom of the pyrrole ring is replaced with a hydrogen atom can be mentioned. For the sake of brevity, the explicit chemical structures of each are omitted.

[0087] Furthermore, specific examples of structural units such as those shown below are also listed.

[0088]

[0089] (IIA-1-7) As long as the effects of the present invention are not impaired, the structural unit A may contain one or more structural units having an aromatic ring other than those of formula (A) in (IIA-1) above.

[0090] Preferably, such aromatic rings have from 6 to 30, more preferably from 6 to 24, carbon atoms.

[0091] Preferably, the aromatic ring 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 heterocyclic ring or an aliphatic ring.

[0092] The aromatic ring may have any substituent, and the substituent preferably contains a heteroatom. In addition, the aromatic ring may have two or more aromatic rings connected by a linking group, and the linking group preferably contains a heteroatom. Examples of the heteroatom include an oxygen atom, a nitrogen atom, and a sulfur atom.

[0093] Preferably, the "aromatic ring" is an organic group having 6 to 30, or 6 to 24 carbon atoms, containing at least one heteroatom selected from N, S, and O on, within, or between the rings.

[0094] 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 atoms 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.

[0095] 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 ２ Examples 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.

[0096] For example, examples of skeletons used in the unit structure A other than that of formula (A) include the following skeletons.

[0097] (Examples of amine skeletons)

[0098] (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.

[0099] The unit structure A other than that of formula (A) is preferably at least one selected from the following: Note that the positions of the two bonds shown in each unit structure described below are shown merely for convenience, and each bond can extend from any possible carbon atom, and the positions are not limited thereto.

[0100] (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-) -NH- can also have a structure in which the hydrogen atom on N is substituted.

[0101]

[0102] (IIA-2) The novolak resin is preferably a compound represented by the following formula (AB): The compound includes a composite unit structure AB represented by:

[0103] In formula (AB), n represents the number of composite unit structures AB, and unit structure A is represented by formula (A) described in (IIA-1) above.

[0104] (IIA-2-1) 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) above], and includes structures represented by formula (B1), (B2), or (B3) described in (IIA-2-2) to (IIA-2-4) below. Unit Structure B can link two unit structures A together by forming a covalent bond with a carbon atom on a pyrrole ring of Unit Structure A.

[0105] 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), and (C3), which will be described later in (IIA-2-2-3), (IIA-2-3-2), and (IIA-2-4-3), respectively, as an equivalent unit structure.

[0106] (IIA-2-2) Formula (B1) In formula (B1), R １１ and R １２ each independently represents a hydrogen atom, an aromatic ring having 6 to 30 carbon atoms which may have a substituent, a heterocycle 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.

[0107] Furthermore, the two bonds in formula (B1) can be covalently bonded to the pyrrole ring in the structural unit A.

[0108] (IIA-2-2-1) In the definitions of R and R' in formula (B1), the terms "aromatic ring" and "heterocycle" can be referred to above in (I-3) and (I-4).

[0109] R in formula (B1) １１ , and R １２In the definition of the above, 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, and 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, 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, 3-ethyl-cyclobutyl group, 1,2-dimethyl-cyclobutyl group, 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,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.

[0110] Preferably, R １１ , and R １２ are each independently phenyl, naphthalenyl, anthracenyl, phenanthrenyl, naphthacenyl, or pyrenyl.

[0111] (IIA-2-2-2) The unit structure containing the structure represented by formula (B1) may also 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, one of the two bonds in each structure of formula (B1) is bonded to the linking group, as shown in formula (B11) below.

[0112] 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 ｘ１ )-, R ｘ１ 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).

[0113] [X ２ is a methylene group, an oxygen atom, -N(R ｘ２ )-, R ｘ２ represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aromatic hydrocarbon group having 5 to 20 carbon atoms.] 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.

[0114]

[0115] (IIA-2-2-3) In addition, R in formula (B1) １１ and R １２ When at least one of the aromatic rings is an aromatic ring [for example, R １２ may be bonded to another structural unit B.

[0116] In this case, 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.), it can also be substituted for at least one composite unit structure A-B 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 remaining bond from the linking carbon atom shown in formula (C1) may be bonded to the aromatic ring of unit structure A, thereby extending the polymer chain.

[0117] (IIA-2-2-4) 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.

[0118]

[0119] (IIA-2-3) In formula (B2), Z ０represents an aromatic ring residue or 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.

[0120] J １ and J ２ each 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.

[0121] (IIA-2-3-1) Furthermore, the unit structure containing the structure represented by formula (B2) may contain a structure in which two or three identical or different structures of formula (B2) are bonded to a divalent or trivalent linking group to form a dimer or trimer structure, as in (IIA-2-2-2) above for formula (B1).

[0122] (IIA-2-3-2) In addition, in the embodiment in which an aromatic ring is contained in formula (B2) [Z in formula (B2)] ０ ], and therefore, similarly to (IIA-2-2-3) of the formula (B1), the aromatic ring [for example, Z ０ Ａｒ The aromatic ring in the formula (B21) may be additionally bonded to another structural unit B [the vertical bond in the formula (B21)].

[0123] [In formula (B21), Z ０ Ａｒ is 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 ０Ａｒ 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 polymer chain may be extended by bonding to the aromatic ring of the unit structure A via a bond from the remaining connecting carbon atom shown in formula (C2).

[0124] (IIA-2-3-3) 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.

[0125]

[0126] (IIA-2-4) Formula (B3)

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] x and y represent the numbers X and Y, respectively, and each independently represents 0 or 1.

[0132] 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.

[0133] Furthermore, formula (B3) may optionally contain linking carbon atoms other than carbon atom 1 and carbon atom 2 [see (IIA-2-4-2) 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.

[0134] (IIA-2-4-1) As in (IIA-2-2-2) 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.

[0135] (IIA-2-4-2) 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.

[0136] 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.

[0137]

[0138] (IIA-2-4-3) 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.

[0139] 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 １The 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.

[0140] 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.

[0141] 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 Ar １ and aromatic monocyclic rings belonging to the formula (I) may be arranged alternately to form a condensed ring.

[0142] Furthermore, X, Y, x, and y are defined as in formula (B3).

[0143] 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 ] may be bonded to another unit structure B, and at the same time, the remaining connecting carbon atom shown in formula (C3) may be bonded to the aromatic ring of unit structure A, thereby extending the polymer chain.

[0144] (IIA-2-4-4) As a more specific structure of formula (C3), 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.

[0145] In addition, k １ Tok ２ It can also function as unit structure A.

[0146] 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.

[0147] In addition, k １ Tok ２ , k １ and m or k ２ and m, it can also function as a unit structure A.

[0148] 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.

[0149] 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.

[0150] In the above specific examples, when there is no bond from the aromatic ring, it can be a specific example of a polymer terminal.

[0151] (IIA-3) 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, HOB-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 about 1 to 3 carbon atoms.

[0152] The ring-containing compound and the oxygen-containing compound may each be used alone or in combination of two or more. In this condensation reaction, the oxygen-containing compound can be used in an amount of 0.1 to 10 moles, preferably 0.1 to 2 moles, per mole of the ring-containing compound.

[0153] Examples of the catalyst 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 usually 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 when multiple types are used).

[0154] The condensation reaction can be carried out without a solvent, but is usually 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, dioxane, 1,2-dichloromethane, 1,2-dichloroethane, toluene, N-methylpyrrolidone, and dimethylformamide. The condensation reaction temperature is usually 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.

[0155] 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.

[0156] (IIB) Solvent The resist underlayer film-forming composition of one embodiment of the present invention contains a solvent.

[0157] The solvent is not particularly limited as long as it can dissolve the specific novolak resin and other optional components added as needed.

[0158] (IIB-1) Examples of the solvent 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, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, 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, 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 monomethyl 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, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-methoxybutyrate Examples of suitable solvents include methyl acetoacetate, 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, 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.

[0159] (IIB-2) A solvent having a boiling point of 160°C or higher may be used in combination with a solvent having a boiling point of less than 160°C.

[0160] As such a high-boiling point solvent, for example, the following compounds described in WO 2018 / 131562 (A1) can be preferably used.

[0161] [R in formula (i)] １ , R ２ and R ３each 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.

[0162] 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.

[0163] (IIC) Acid and / or Salt Thereof and / or Acid Generator The resist underlayer film forming composition, which is one embodiment of the present invention, can optionally contain an acid and / or a salt thereof and / or an acid generator.

[0164] (IIC-1) Examples of the acid include p-toluenesulfonic acid, trifluoromethanesulfonic acid, salicylic acid, 5-sulfosalicylic acid, 4-phenolsulfonic acid, camphorsulfonic acid, 4-chlorobenzenesulfonic acid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, citric acid, benzoic acid, hydroxybenzoic acid, and naphthalenecarboxylic acid.

[0165] The salt may be a salt of the above-mentioned acid, and is not limited thereto, but ammonia derivative salts such as trimethylamine salts and triethylamine salts, pyridine derivative salts, morpholine derivative salts, etc. may be suitably used.

[0166] The acid and / or salt thereof may be used singly or in combination of two or more kinds, and the blending amount is usually 0.0001 to 20 mass %, preferably 0.0005 to 10 mass %, and more preferably 0.01 to 5 mass %, based on the total solid content.

[0167] (IIC-2) Examples of the acid generator include a thermal acid generator and a photoacid generator.

[0168] (IIC-2-1) Examples of thermal acid generators include 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, K-PURE (registered trademark) CXC-1612, CXC-1614, TAG-2172, TAG-2179, TAG-2678, TAG2689, and TAG2700 (manufactured by King Industries), and SI-45, SI-60, SI-80, SI-100, SI-110, and SI-150 (manufactured by Sanshin Chemical Industry Co., Ltd.), and other organic sulfonic acid alkyl esters.

[0169] (IIC-2-2) A photoacid generator generates acid when the resist is exposed to light. This allows the acidity of the underlayer film to be adjusted. This is one way to match the acidity of the underlayer film to that of the upper layer resist. Furthermore, adjusting the acidity of the underlayer film allows the pattern shape of the resist formed on the upper layer to be adjusted.

[0170] Examples of the photoacid generator contained in the resist underlayer film-forming composition of the present invention include onium salt compounds, sulfonimide compounds, and disulfonyldiazomethane compounds.

[0171] Examples of the onium salt compound include iodonium salt compounds such as diphenyliodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-normal butanesulfonate, diphenyliodonium perfluoro-normal octanesulfonate, diphenyliodonium camphorsulfonate, bis(4-tert-butylphenyl)iodonium camphorsulfonate, and bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate; and sulfonium salt compounds such as triphenylsulfonium hexafluoroantimonate, triphenylsulfonium nonafluoro-normal butanesulfonate, triphenylsulfonium camphorsulfonate, and triphenylsulfonium trifluoromethanesulfonate.

[0172] Examples of the sulfonimide compound include N-(trifluoromethanesulfonyloxy)succinimide, N-(nonafluoronormalbutanesulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, and N-(trifluoromethanesulfonyloxy)naphthalimide.

[0173] Examples of the disulfonyldiazomethane compound include bis(trifluoromethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(2,4-dimethylbenzenesulfonyl)diazomethane, and methylsulfonyl-p-toluenesulfonyldiazomethane.

[0174] (IIC-2-3) The acid generators can be used alone or in combination of two or more.

[0175] When an acid generator is used, the proportion thereof is 0.01 to 10 parts by mass, or 0.1 to 8 parts by mass, or 0.5 to 5 parts by mass, relative to 100 parts by mass of the solid content of the resist underlayer film-forming composition.

[0176] (IID) Other Optional Components The resist underlayer film-forming composition of one embodiment of the present invention may contain, in addition to the above, a crosslinking agent, a surfactant, a light-absorbing agent, a rheology adjuster, an adhesion aid, and the like, as necessary.

[0177] (IID-1) Crosslinking Agents Typical crosslinking agents include aminoplast crosslinking agents and phenoplast crosslinking agents.

[0178] As the crosslinking agent, a crosslinking agent having high heat resistance can be used, and as the crosslinking agent having high heat resistance, a compound containing a crosslink-forming substituent having an aromatic ring (e.g., a benzene ring or a naphthalene ring) in the molecule can be preferably used.

[0179] (IID-1-1) Examples of aminoplast crosslinking agents include highly alkylated, alkoxylated, or alkoxyalkylated melamine, benzoguanamine, glycoluril, urea, and polymers thereof. Crosslinking agents having at least two crosslink-forming substituents are preferred, such as methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguwanamine, butoxymethylated benzoguwanamine, methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, and methoxymethylated thiourea. Condensates of these compounds can also be used.

[0180] Preferably, it is at least one selected from the group consisting of tetramethoxymethyl glycoluril and hexamethoxymethyl melamine.

[0181] Some specific examples are as follows:

[0182]

[0183] (IID-1-2) Examples of phenoplast crosslinking agents include highly alkylated, alkoxylated, or alkoxyalkylated aromatics and their polymers. Preferred examples include 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.

[0184] 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).

[0185] The above R １１ , R １２ , R １３ , and R １４ is 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 number of 2 to 100 or 2 to 50 can be used.

[0186] Some specific examples are as follows:

[0187]

[0188] (IID-1-3) Crosslinking agents such as aminoplast crosslinking agents and phenoplast crosslinking agents may be used alone or in combination of two or more. The aminoplast crosslinking agent may be produced by a method known per se or a method equivalent thereto, or a commercially available product may be used.

[0189] The amount of the crosslinking agent, such as an aminoplast crosslinking agent or a phenoplast crosslinking agent, used varies depending on the coating solvent used, the base substrate used, the required solution viscosity, the required film shape, and the like, 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 is 80 mass % or less, 50 mass % or less, 40 mass % or less, 20 mass % or less, or 10 mass % or less, relative to the total solids content of the resist underlayer film-forming composition of the present invention.

[0190] (IID-2) Surfactant The resist underlayer film forming composition according to the present invention can contain a surfactant in order to prevent pinholes, striations, and the like from occurring and to further improve coatability against surface irregularities.

[0191] Examples of surfactants include nonionic surfactants such as polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkylaryl ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether; polyoxyethylene-polyoxypropylene block copolymers; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate; and polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate. Examples of suitable surfactants include fluorine-based surfactants such as F-TOP 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), and 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.).

[0192] 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.

[0193] (IID-3) Other Additives 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), such as 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. 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, etc. can be suitably used. The light-absorbing agent is usually blended in an amount of 10% by mass or less, and preferably 5% by mass or less, based on the total solid content of the resist underlayer film-forming composition according to the present invention.

[0194] The rheology modifier is added primarily to improve the fluidity of the resist underlayer film-forming composition, particularly in the baking step, to improve the film thickness uniformity of the resist underlayer film and the ability of the resist underlayer film-forming composition to fill 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 incorporated 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.

[0195] The adhesion promoter is added mainly for the purpose of improving the adhesion between the substrate or resist and the resist underlayer film-forming composition, and 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; 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.

[0196] 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.

[0197] [III: Resist Underlayer Film] The resist underlayer film can be formed, for example, as follows using the resist underlayer film-forming composition according to the present invention.

[0198] Substrates used in the manufacture of semiconductor devices (e.g., silicon wafer substrates, silicon dioxide coated substrates (SiO２ The resist underlayer film-forming composition according to one embodiment of the present invention is applied onto 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 800°C and a baking time of 0.3 to 60 minutes. Preferably, the baking temperature is 150°C to 400°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 may also be used. The thickness of the underlayer film formed here is, for example, 10 to 1000 nm, 20 to 500 nm, 30 to 400 nm, or 50 to 300 nm. Furthermore, if a quartz substrate is used as the substrate, a replica of the quartz imprint mold (mold replica) can be produced.

[0199] Furthermore, an adhesion layer and / or a silicon-containing 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 according to one embodiment of the present invention. For example, an adhesion layer as described in JP-A-2013-202982 or JP-A-5827180, a silicon-containing resist underlayer film (inorganic resist underlayer film)-forming composition as described in WO 2009 / 104552 (A1) can be formed by spin coating, or a Si-based inorganic material film can be formed by CVD or the like.

[0200] 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.

[0201] [IV: Method for manufacturing a semiconductor device] (IVA) (i) A method for manufacturing a semiconductor device, which is one aspect of the present invention, includes: a step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition, which is one aspect of the present invention; a step of forming a resist film on the resist underlayer film; a step of forming a resist pattern on the resist film by irradiating with light or an electron beam and developing; a step of etching and patterning the resist underlayer film via the resist pattern; and a step of processing a semiconductor substrate using the patterned resist underlayer film.

[0202] (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 the resist underlayer film-forming composition according to one aspect of the present invention; forming a hard mask on the resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern on the resist film by irradiating with light or an electron beam and developing; etching and patterning the hard mask via the resist pattern; etching and patterning the resist underlayer film via the patterned hard mask; and processing a semiconductor substrate via the patterned resist underlayer film.

[0203] (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 resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern on the resist film by irradiating with light or an electron beam and developing; etching and patterning the hard mask via the resist pattern; etching and patterning the resist underlayer film via the patterned hard mask; removing the hard mask; and processing a semiconductor substrate via the patterned resist underlayer film.

[0204] (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 resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern on the resist film by irradiating with light or an electron beam and developing; etching and patterning the hard mask through the resist pattern; etching and patterning the resist underlayer film through the etched hard mask; removing the hard mask; 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 through the patterned vapor-deposited film (spacer).

[0205] The manufacturing methods (i) to (iv) above can be used to process a semiconductor substrate.

[0206] (IVB) The step of forming a resist underlayer film using the resist underlayer film forming composition of one embodiment of the present invention is as described above in [III: Resist Underlayer Film].

[0207] 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 process, and a resist pattern may be formed thereon [(IVA)(ii) to (iv) above].

[0208] The hard mask may be a coating film of an inorganic material or a vapor-deposited film of an inorganic material formed by a vapor deposition method such as CVD, PVD, or ALD, and may be a SiON film, a SiN film, or a SiO ２ An example is a membrane.

[0209] Furthermore, an anti-reflective coating (BARC) may be formed on this hard mask, or a resist shape correction film without anti-reflective properties may be formed.

[0210] In the step of forming the resist pattern, 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 underlayer.

[0211] The etching step performed after the formation of the resist pattern is performed by dry etching.

[0212] (IVC) The resist film may be patterned by a nanoimprint method or a self-assembled film method.

[0213] In the nanoimprint method, a resist composition is molded using a patterned mold that is transparent to irradiated light, while 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 (e.g., polystyrene-polymethyl methacrylate).

[0214] In the nanoimprint method, before applying the curable composition that will form the resist film, a silicon-containing layer (hard mask layer) may be optionally formed on the resist underlayer film by coating or vapor deposition, and further an adhesion layer may be formed on the resist underlayer film or the silicon-containing layer (hard mask layer) by coating or vapor deposition, and the curable composition that will form the resist film may be applied on the adhesion layer.

[0215] (IVD) 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 , C４ 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.

[0216] (IVE) In addition, wet etching may be performed to simplify the process 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 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:

[0217] 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.

[0218] Polymer Synthesis Polymers used in resist underlayer films having structural formulae (S1) to (S17) and (S'1) to (S'17) were synthesized using Compound Group A, Compound Group B, Compound Group C, Catalyst Group D, Solvent Group E, Reprecipitation Solvent Group F, and Separation Solvent G shown below.

[0219] ○Compound groups A to C

[0220] Catalyst group D, solvent group E, reprecipitation solvent group F, separation solvent group G Methanesulfonic acid: D1 Tetrabutylammonium iodide: D2 Cyclohexanone (=CYH): E1 Tetrahydrofuran (=THF): E2 25% aqueous sodium hydroxide solution: E3 Methanol / aqueous ammonia: F1 Methanol / water: F2 Butyl acetate / water: G1

[0221] Synthesis Example 1: 10.0 g of A1, 3.6 g of C1, 20.5 g of C2, and 51.1 g of E1 were placed in a flask and stirred. Subsequently, a mixed solution of 12.8 g of E1 and 0.3 g of D1 was added dropwise at room temperature under nitrogen and allowed to react for approximately 1 hour. After the reaction was stopped, the mixture was reprecipitated with F1, and the resin was dried to obtain (S1). The weight-average molecular weight Mw measured by GPC in terms of polystyrene was approximately 1,700. The resulting resin was dissolved in PGMEA, and ion exchange was performed using a cation exchange resin and an anion exchange resin for 4 hours to obtain a solution of the target compound. Resins S2 to S17 were synthesized using the same procedure.

[0222]

[0223]

[0224] Synthesis Example 18: 10.0 g of S1, 21.1 g of C15, 1.1 g of D2, 48.3 g of E2, and 21.7 g of E3 were placed in a flask. The mixture was heated to 55°C under nitrogen and allowed to react for approximately 20 hours. After the reaction was stopped, the liquid separation procedure was repeated using G1, and the organic layer was concentrated, reprecipitated using F2, and dried to obtain resin (S'1). The weight-average molecular weight Mw measured by GPC in terms of polystyrene was approximately 2,100. The obtained resin was dissolved in PGMEA, and ion exchange was performed using a cation exchange resin and an anion exchange resin for 4 hours to obtain a solution of the target compound. Resins S'2 to S'17 were synthesized using the same procedure.

[0225]

[0226] The above structural formula shows the corresponding structure when all alkynylatable sites are alkynylated.

[0227] Preparation of Resist Underlayer Films Polymers (S1) to (S17) and (S'1) to (S'17), crosslinking agents (CL1 to CL2), acid generators (Ad1 to Ad2), solvents (propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), cyclohexanone (CYH)), and Megafac R-40 (manufactured by DIC Corporation, H1) as a surfactant were mixed in the proportions shown in the table below (the weight proportions of the crosslinking agent, acid generator, and surfactant are shown when the weight of the polymer is 100; for the solvents, the weight proportions of each solvent are shown when the total solvent weight is 100), and the mixture was filtered through a 0.1 μm polytetrafluoroethylene microfilter to prepare resist underlayer film materials (M1 to M17) and comparative examples (Comparative M1 to M17).

[0228]

[0229]

[0230] [Solvent Resistance Test for Resist Solvents] The resist underlayer film materials of Comparative Examples 1-17 and Examples 1-20 were applied to a silicon wafer using a spin coater and baked in the atmosphere at the specified temperature and for the specified time shown in the table to form a resist underlayer film with a film thickness of approximately 130 nm. 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 to remove residual solvent, thereby confirming its solvent resistance. A sample with a film thickness reduction of 1% or less after immersion in thinner was evaluated as "good" (Table 1). Samples evaluated as "good" were judged to have sufficient curability to be used as a resist underlayer film.

[0231] [Curability Test (Confirmation of Curing Initiation Temperature)] The resist underlayer film materials of Comparative Examples 1-17 and Examples 1-20 were applied to a silicon wafer using a spin coater and baked in the atmosphere at the specified temperature listed in the table for 60 seconds to form a resist underlayer film with a film thickness of approximately 130 nm. 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 to remove residual solvent, thereby confirming its resistance to solvent. Cases where the film thickness reduction rate before and after immersion in thinner at each baking temperature was smaller than that of the comparative example (composition corresponding to the example without propargyl groups introduced) were judged as ◯ (Table 1). Samples judged as ◯ indicate that they begin to cure at a lower temperature range than the comparative example.

[0232]

[0233] [Solvent Resistance Test in Nitrogen] The resist underlayer film materials of Comparative Examples 1-17, Examples 1-4, 6, 10, 12, and 18-19 were applied to silicon wafers using an ACT-8 coating machine manufactured by Tokyo Electron Limited, and baked under nitrogen at the predetermined temperatures and for the predetermined times shown in the tables to form 130 nm resist underlayer films. As described above, the films were immersed in a 7 / 3 PGME / PGMEA mixture for 60 seconds, spin-dried, and baked at 100°C for 30 seconds to remove residual solvent, thereby confirming their solvent resistance. Cases in which the rate of film thickness reduction before and after thinner immersion was smaller than that of the comparative examples (structures corresponding to the examples without a propargyl group introduced) were evaluated as "good" (Table 2).

[0234]

[0235] [Measurement of Etching Rate] The resist underlayer film materials of Comparative Example 1-17 and Example 1-20 were each applied onto a silicon wafer using a spin coater. The resist underlayer film was baked on a hot plate at the predetermined temperature for the predetermined time shown in the table to form a 130 nm thick resist underlayer film. O was used as the etching gas. ２ / N ２ Gas or CF ４The dry etching rate was measured using the gas. The dry etching rate ratio shown in the table is the dry etching rate ratio of (resist underlayer film) / (phenol novolac resin film) (Table 3).

[0236] The etcher and etching gas used in the etching measurement were as follows: RIE-200NL (manufactured by Samco): CF ４ 50 sccm RIE-200NL (manufactured by Samco): O ２ / N ２ 10sccm / 200sccm

[0237] [Optical Constant Measurement] The resist underlayer film materials of Comparative Examples 1-17 and Examples 1-20 were each applied to a silicon wafer using a spin coater. The resist underlayer films were baked on a hot plate at the specified temperatures and for the specified times shown in the table to form resist underlayer films (film thickness 50 nm). The refractive index (n value) and optical extinction coefficient (k value, also called extinction coefficient) of these resist underlayer films at a wavelength of 193 nm were measured using a spectroscopic ellipsometer (Table 3).

[0238] [Film Shrinkage Measurement] The resist underlayer film materials of Comparative Example 1-17 and Example 1-20 were each applied onto a silicon wafer using a spin coater, and then baked at 160°C for 60 seconds, and the film thickness was measured. Then, the film was further baked at 350°C for 60 seconds, and the film thickness was measured. Compared to the comparative example (the structure corresponding to the example without a propargyl group), samples with a small difference in film thickness between when baked at 160°C and when baked at 350°C were judged to have small film shrinkage and excellent heat resistance, and were therefore judged to be ○ (Table 3).

[0239]

[0240] [Coating and Covering Test on Stepped Substrate] As a coating test on a stepped substrate, a 200 nm thick SiO ２A silicon wafer, a silicon nitride wafer, and a silicon nitride wafer were used. In the case of a stepped substrate, the resist underlayer film may have poorer coatability compared to a silicon wafer without steps. Therefore, whether the resist underlayer film could be evenly coated on the stepped substrate was tested. Visual inspection was performed, and even coating was evaluated as "good." Planarization was evaluated in a trench area (dense pattern area) with a trench width of 50 nm and a pitch of 100 nm present in the substrate. The coating film thickness in the dense area was compared with that in an area without a pattern (open area). The resist underlayer film-forming compositions prepared in Comparative Example 1-17 and Example 1-20 were applied to the substrate, and then baked on a hot plate at the specified temperature for the specified time shown in the table to form a 130 nm resist underlayer film. 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 difference in film thickness between the trench area (patterned portion) and the open area (non-patterned portion) of the uneven substrate (the coating step between the trench area and the open area, which is called the bias). Here, planarization means that the difference in film thickness (Iso-dense bias) of the coating present on the portion where a pattern is present (trench area (patterned portion)) and the portion where a pattern is not present (open area (non-patterned portion)) is small. Those in which the bias was improved compared to the comparative example (the structure corresponding to the example without the propargyl group introduced) were judged to be good (Table 4).

[0241]

[0242] [Test for embedding ability into uneven substrate] As a coating test for uneven substrate, a 200 nm thick SiO ２A substrate, a SiN substrate, and a TiN substrate were used. The embeddability was evaluated in a trench area (dense pattern area) with a trench width of 50 nm and a pitch of 100 nm present in the substrate. The resist underlayer film-forming compositions prepared in the examples and comparative examples in the table below were applied to the substrate, and then baked on a hot plate at the predetermined temperature and for the predetermined time shown in the table to form a 130 nm resist underlayer film. The embeddability of this substrate was observed using a scanning electron microscope (S-4800) manufactured by Hitachi High-Technologies Corporation. The embeddability was judged to be good when the resist underlayer film was able to fill the trench bottom (Table 5).

[0243]

Claims

1. A resist underlayer film forming composition comprising a novolac resin and a solvent, The novolac resin comprises a unit structure A having an aromatic ring, wherein the unit structure A is defined by the following formula (A): 【Chemistry 52】 It includes one or more structural units represented by In the above formula (A), R １ is a substituent on a hydrogen atom or on a nitrogen atom of a pyrrole ring, wherein the substituent is (i) Methylol group; (ii) Linear, branched, or cyclic alkoxymethyl groups having 2 to 20 carbon atoms; or (iii) Represents a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 30 carbon atoms; R ２ is an optional substituent on a carbon atom constituting the pyrrole ring, (iv); the same group of substituents as in (iii) above; or (v) Acyl groups having 1 to 15 carbon atoms, alkoxy groups having 1 to 15 carbon atoms, aryloxy groups having 6 to 15 carbon atoms, alkoxycarbonyl groups having 1 to 15 carbon atoms, aryloxycarbonyl groups having 7 to 15 carbon atoms, monosubstituted amino groups having 1 to 15 carbon atoms, or disubstituted amino groups having 2 to 30 carbon atoms; (vi) Represents a hydroxyl group, nitro group, amino group, cyano group, carboxyl group, trifluoromethyl group, or halo group; However, with respect to (ii) to (v) above, the hydrocarbon chain portion may be further substituted with an oxygen atom-containing substituent, a sulfur atom-containing substituent, a nitrogen atom-containing substituent, an aryl group or a halo group, or the hydrocarbon chain portion may be further interrupted with an oxygen atom-containing substituent, a sulfur atom-containing substituent, a nitrogen atom-containing substituent or an arylene group. Also, R in novolac resin １ and R ２ At least a portion of these is a substituent having an alkynyl chain with 2 to 10 carbon atoms, n is a substituent R ２ Represents the number of R, and if n is multiple, it represents multiple R ２ They may be the same or different. * indicates a bonding hand; a resist underlayer forming composition.

2. The novolac resin, The following formula (AB): 【Chemistry 53】 A resist underlayer film forming composition according to claim 1, comprising a composite unit structure A-B represented by, In the above formula (AB), n represents the number of composite unit structures A-B, Unit structure A is represented by formula (A) described in claim 1, Unit structure B represents one or more unit structures including the structure represented by the following formulas (B1), (B2), or (B3): * indicates a bonding hand; a resist underlayer forming composition. 【Chemistry 54】 [In formula (B1), R １１ and R １２ Each of these independently represents a hydrogen atom, an aromatic ring residue having 6 to 30 carbon atoms which may have substituents, a heterocyclic residue having 3 to 30 carbon atoms which may have substituents, or a linear, branched, or cyclic alkyl group having 10 or fewer carbon atoms which may have substituents. * indicates a bonding hand. 【Transformation 55】 [In formula (B2), Z ０ represents an aromatic ring residue, 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 of these independently represents a divalent organic group which may have direct bonding or substituents, * indicates a bonding hand. 【Transformation 56】 [In formula (B3), Z is a monocyclic, dicyclic, tricyclic, or tetracyclic fused ring having 4 to 25 carbon atoms, which may have substituents, and the monocyclic ring is a non-aromatic monocyclic ring; at least one of the monocyclic rings constituting the dicyclic, tricyclic, and tetracyclic rings is a non-aromatic monocyclic ring, and the remaining monocyclic rings may be aromatic or non-aromatic monocyclic rings, and the monocyclic, dicyclic, tricyclic, or tetracyclic fused ring may further form fused rings with one or more aromatic rings to form a fused ring of five or more rings. X and Y are the same or different, -CR 31 R 32 - Represents the base, R 31 and R 32 Each of these is either the same or different, representing a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. x and y represent the numbers X and Y, respectively, and each independently represents either 0 or 1. 【Chemistry 57】 It is bonded to any of the carbon atoms constituting the non-aromatic monoring of Z (referred to as "carbon atom 1") (when x=1), or extends from carbon atom 1 (when x=0), 【Chemistry 58】 It is bonded to any of the carbon atoms constituting the non-aromatic monoring of Z (referred to as "carbon atom 2") (when y=1), or extends from carbon atom 2 (when y=0), Carbon atoms 1 and 2 may be the same or different, and if they are different, they may belong to the same non-aromatic monoring or to different non-aromatic monorings. * indicates a bonding hand.

3. R in novolac resin １ and R ２ The aforementioned alkynyl chain is given by the following formula: 【Chemistry 59】 [Here, * indicates a bonding hand. R ３ It is a single bond or a divalent organic group having 1 to 7 carbon atoms. R ４ is a hydrogen atom, or a monovalent organic group having 1 to 7 carbon atoms. R ３ and R ４ The resist underlayer film forming composition according to claim 1, wherein the total number of carbon atoms is 0 to 8.

4. The resist underlayer film forming composition according to claim 1, wherein the solvent comprises a solvent with a boiling point of 160°C or higher.

5. The resist underlayer forming composition according to claim 1, further comprising an acid and / or a salt thereof and / or an acid generator.

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

7. The resist underlayer film forming composition according to claim 6, wherein the crosslinking agent is an aminoplast crosslinking agent or a phenoplast crosslinking agent.

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

9. A resist underlayer film on a semiconductor substrate, which is a fired product of a coated film made from the resist underlayer film forming composition according to any one of claims 1 to 8.

10. A method for forming a resist pattern used in semiconductor manufacturing, comprising the step of applying a resist underlayer forming composition according to any one of claims 1 to 8 onto a semiconductor substrate and firing it to form a resist underlayer film.

11. A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film forming composition described in claim 1, A process of forming a resist film on top of a resist underlayer film, A process of forming a resist pattern on a resist film by irradiation with light or an electron beam and development. A step of etching the resist underlayer film via a resist pattern, and Process of processing semiconductor substrates with a patterned resist underlayer film. A method for manufacturing a semiconductor device containing [a specific component].

12. A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film forming composition described in claim 1, A process of forming a hard mask on top of the resist underlayer film, Furthermore, a step of forming a resist film on top of the hard mask. A process of forming a resist pattern on a resist film by irradiation with light or an electron beam and development. The process of etching a hard mask through a resist pattern, A step of etching the resist underlayer film through a patterned hard mask, and A method for manufacturing a semiconductor device, comprising the step of processing a semiconductor substrate via a patterned resist underlayer film.

13. A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film forming composition described in claim 1, A process of forming a hard mask on top of the resist underlayer film, Furthermore, a step of forming a resist film on top of the hard mask. A process of forming a resist pattern on a resist film by irradiation with light or an electron beam and development. The process of etching a hard mask through a resist pattern, A step of etching the resist underlayer film through a patterned hard mask, The process of removing the hard mask, and A process of processing a semiconductor substrate via a patterned resist underlayer film. A method for manufacturing a semiconductor device containing [a specific component].

14. A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film forming composition described in claim 1, A process of forming a hard mask on top of the resist underlayer film, Furthermore, a step of forming a resist film on top of the hard mask. A process of forming a resist pattern on a resist film by irradiation with light or an electron beam and development. The process of etching a hard mask through a resist pattern, A step of etching the resist underlayer film through the etched hard mask, The process of removing the hard mask, The process of forming a vapor-deposited film (spacer) on the resist underlayer after hard mask removal. The process of processing a vapor-deposited film (spacer) by etching. A step of removing the patterned resist underlayer film and leaving the patterned vapor-deposited film (spacer), and A method for manufacturing a semiconductor device, comprising the step of processing a semiconductor substrate via a patterned vapor-deposited film (spacer).

15. The method for manufacturing a semiconductor device according to any one of claims 12 to 14, wherein the hard mask is formed by coating or depositing an inorganic substance.

16. The method for manufacturing a semiconductor device according to any one of claims 11 to 14, wherein the resist film is patterned by a nanoimprint method or a self-assembled film.

17. A method for manufacturing a semiconductor device according to any one of claims 13 to 14, wherein the hard mask is removed by etching or by an alkaline chemical solution.

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