Composition for forming resist underlayer film and method for manufacturing semiconductor substrate

Abstract

Provided are: a composition for forming a resist underlayer film capable of forming a resist underlayer film having excellent pattern rectangularity and an excellent pattern peeling suppression property; and a method for manufacturing a semiconductor substrate. This composition for forming a resist underlayer film contains a polymer and a solvent, wherein the composition for forming a resist underlayer film further contains a compound having a moiety represented by formula (i), or the polymer contains a moiety represented by formula (i), and the polymer has at least one monovalent group (X) selected from the group consisting of a phenolic hydroxyl group-containing group and groups represented by formulae (2-1)-(2-8). (In the formula, X- represents -COO- or -SO3 -. W is a (1+p)-valent organic group. However, when X- is -SO3 -, a group other than a fluorine atom or a hydrogen atom is bonded to the α-position carbon of the sulfur atom of the -SO3 - group in W. Z+ is a q-valent organic cation.)

Description

Composition for forming a resist underlayer film and method for manufacturing a semiconductor substrate

[0001] This invention relates to a composition for forming a resist underlayer film and a method for manufacturing a semiconductor substrate.

[0002] In semiconductor substrate manufacturing, a multilayer resist process is used to form patterns by exposing and developing a resist film that has been laminated on a substrate via a resist underlayer film such as an organic underlayer film or a silicon-containing film. In this process, the resist pattern is used as a mask to etch the resist underlayer film, and the substrate is further etched using the resulting resist underlayer film pattern as a mask, thereby forming a desired pattern on the semiconductor substrate. Various studies have been conducted on compositions for forming resist underlayer films (see International Publication No. 2013 / 141015).

[0003] International Publication No. 2013 / 141015

[0004] In recent years, semiconductor devices have become even more highly integrated, and the exposure light used is tending to be shortened from KrF excimer lasers (248 nm) and ArF excimer lasers (193 nm) to extreme ultraviolet light (13.5 nm, hereinafter also referred to as "EUV"). Furthermore, in EUV lithography, metal-containing resist films are increasingly being used instead of organic resist films.

[0005] As the line width of resist patterns becomes finer, the underlayer film for resists is required to have pattern rectangularity to ensure the rectangular shape of the resist pattern and pattern peeling suppression properties to prevent the resist pattern from peeling off.

[0006] The present invention has been made based on the circumstances described above, and its objective is to provide a resist underlayer film formation composition and a semiconductor substrate manufacturing method that can form a resist underlayer film with excellent pattern rectangularity and pattern peeling suppression.

[0007] In one embodiment, the present invention provides a composition for forming an underlayer resist film containing a polymer and a solvent (hereinafter, also referred to as "[B] solvent"), wherein at least: the composition for forming an underlayer resist film further contains a compound having a partial structure represented by the following formula (i) (hereinafter, also referred to as "partial structure (i)") (hereinafter, also referred to as "[D1] compound"), or the polymer contains a partial structure represented by the following formula (i) (hereinafter, the polymer containing partial structure (i) is also referred to as "[D2] polymer"); and the polymer has at least one monovalent group (X) selected from the group consisting of a group having a phenolic hydroxyl group, a group represented by the following formula (2-1), a group represented by the following formula (2-2), a group represented by the following formula (2-3), a group represented by the following formula (2-4), a group represented by the following formula (2-5), a group represented by the following formula (2-6), a group represented by the following formula (2-7), and a group represented by the following formula (2-8). The present invention relates to the composition for forming an underlayer resist film. (In the above formula (i), X - is -COO - or -SO ３ - . W is a 1+p-valent organic group having 1 to 40 carbon atoms, provided that when X - is -SO ３ - , a group other than a fluorine atom or a hydrogen atom is bonded to the carbon at the α-position to the sulfur atom of -SO ３ - in W. Z ＋ is a q-valent organic cation. * represents a bond to another partial structure in the polymer or the compound. p and q are each independently 0 or 1, provided that when * is a bond to another partial structure in the polymer, p+q is 1.) (In the above formulas (2-1) to (2-8), R ７ are each independently a divalent organic group having 1 to 20 carbon atoms or a single bond. R ８ , R ９ , R １０ and R １３Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. Cy is a ring structure with 3 to 20 members, formed together with the two carbon atoms in formula (2-2). １１ R is a hydrogen atom, a monovalent organic group having 1 to 20 carbon atoms, or a single bond. １２ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. ** is a bond with an atom constituting Cy. However, R １１ If it is a single bond, R １１ It bonds with **. * represents the bonding site with each atom that makes up the polymer.

[0008] In other embodiments, the present invention relates to a method for manufacturing a semiconductor substrate, comprising the steps of: coating a substrate directly or indirectly with a resist underlayer film forming composition; forming a resist film on the resist underlayer film formed by the resist underlayer film forming composition coating step; exposing the resist film with radiation; and developing at least the exposed resist film, wherein the resist underlayer film forming composition contains a polymer and a solvent, and at least the resist underlayer film forming composition further contains a compound having a substructure represented by the following formula (i), or the polymer contains a substructure represented by the following formula (i), and the polymer has at least one monovalent group (X) selected from the group consisting of a group having a phenolic hydroxyl group, a group represented by the following formula (2-1), a group represented by the following formula (2-2), a group represented by the following formula (2-3), a group represented by the following formula (2-4), a group represented by the following formula (2-5), a group represented by the following formula (2-6), a group represented by the following formula (2-7), and a group represented by the following formula (2-8). (In the above equation (i), X - -COO - or -SO ３ - W is an organic group with 1 to 40 carbon atoms and a valency of 1+p. However, X - ga-SO ３ - If so, -SO in W ３ -A group other than a fluorine atom or a hydrogen atom is bonded to the α-carbon of the sulfur atom. ＋ p is a q-valent organic cation. * represents a bond with another substructure in the polymer or compound. p and q are independently either 0 or 1. However, if * is a bond with another substructure in the polymer, then p + q is 1. (In the above equations (2-1) to (2-8), R ７ Each of these is independently a divalent organic group or single bond having 1 to 20 carbon atoms. ８ , R ９ , R １０ and R １３ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. Cy is a ring structure with 3 to 20 members, formed together with the two carbon atoms in formula (2-2). １１ R is a hydrogen atom, a monovalent organic group having 1 to 20 carbon atoms, or a single bond. １２ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. ** is a bond with an atom constituting Cy. However, R １１ If it is a single bond, R １１ It bonds with **. * represents the bonding site with each atom that makes up the polymer.

[0009] In this specification, unless otherwise specified, the following terms have the meanings: "Fused ring" means a polycyclic structure formed by two adjacent rings sharing one edge (two adjacent atoms). "Ring assembly" means a structure in which two rings are joined by a single bond. "Spiro ring" means a polycyclic structure formed by two adjacent rings sharing one atom. "Organic group" means a group containing at least one carbon atom. Organic groups include cyano groups, carboxyl groups, formyl groups, etc. "Halogen atom" is a fluorine atom, chlorine atom, bromine atom, or iodine atom. "Substituent" is a halogen atom; hydroxyl group; carboxyl group; cyano group; nitro group; amino group; alkyl group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, acyloxy group, ethenyl group (vinyl group), ethynyl group, or a group in which a hydrogen atom of these groups is substituted with a halogen atom; oxo group (=O); or a group combining these. The same applies to substituents in the case of substitution, among "substituted or unsubstituted." "Divalent heteroatom-containing linking groups" are -CO-, -CS-, -NR'-, -O-, -S-, -SO-, -SO ２ -or a combination of these groups. R' is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. "Monovalent heteroatom-containing substituent" is a hydroxyl group, sulfanyl group, carboxyl group, cyano group, nitro group, amino group, halogen atom, or silyl group. In the structural formula, the abbreviations for substituents are as follows: "Me" represents a methyl group, "Et" represents an ethyl group, "tBu" or "t-Bu" represents a t-butyl group (tertiary butyl group), and "Ph" represents a phenyl group.

[0010] The resist underlayer film formation composition allows for the formation of a film with excellent pattern rectangularity and pattern peeling resistance. The semiconductor substrate manufacturing method utilizes a resist underlayer film formation composition capable of forming a resist underlayer film with excellent resist pattern rectangularity and pattern peeling resistance, enabling the efficient manufacture of semiconductor substrates with good pattern shapes. Therefore, these can be suitably used in the manufacture of semiconductor devices and the like.

[0011] The following describes in detail the resist underlayer film formation compositions and semiconductor substrate manufacturing methods according to each embodiment of the present invention. Preferred combinations of embodiments are also preferred.

[0012] Composition for forming a resist underlayer film The composition for forming a resist underlayer film (hereinafter also referred to as "the composition") contains a polymer and a solvent [B]. The polymer may be a [D2] polymer containing substructure (i), a polymer not containing substructure (i) (hereinafter also referred to as "[A] polymer"), or a mixture of both. If the composition contains only the [A] polymer as the polymer, the composition further contains the [D1] compound. If the composition contains the [D2] polymer, the inclusion of the [D1] compound and the [A] polymer in the composition is optional. Optional components may be included as long as they do not impair the effects of the present invention.

[0013] The composition makes it possible to form a resist underlayer film with excellent pattern rectangularity and pattern peeling suppression. Although the reason for this is not clear, it is presumed to be as follows: The composition contains at least a [D1] compound or a [D2] polymer. Substructure (i) of the [D1] compound or [D2] polymer generates acid when exposed to heat or light. As a result, the underlayer film obtained with the composition generates acid when exposed to extreme ultraviolet light or when the film is heated, creating a sufficient difference in solubility in the interface region on the underlayer side of the organic resist film, or improving adhesion through interaction between the resist film and the acid in the interface region. Furthermore, the generated acid can particularly promote the insolubilization of metal-containing resist films. These effects work synergistically to suppress pattern trailing at the bottom of the resist film, ensuring the rectangularity of the resist pattern, and suppressing pattern peeling.

[0014] The following describes each component contained in the composition.

[0015] <[D2] Polymer> The [D2] polymer includes substructure (i). The [D2] polymer may contain one or more substructures (i). The composition may contain one or more [D2] polymers. The form of the [D2] polymer is not particularly limited and may be any polymerization reactor such as an addition polymerization reactor, a polycondensation reactor, a polyaddition reactor, or an addition-condensation reactor. From the viewpoint of ease of introducing substructure (i), the form of the [D2] polymer is preferably an addition polymerization reactor.

[0016] Substructure (i) is a structure represented by the following formula (i) having an organic acid anion and an organic cation. (In the above equation (i), X - -COO - or -SO ３ - W is an organic group with 1 to 40 carbon atoms and a valency of 1+p. However, X - ga-SO ３ - If so, -SO in W ３ - A group other than a fluorine atom or a hydrogen atom is bonded to the α-carbon of the sulfur atom. ＋ p is a q-valent organic cation. * represents a bond with another substructure in the polymer. p and q are independently either 0 or 1. However, if * is a bond with another substructure in the polymer, then p + q is 1.

[0017] In formula (i) above, the 1+p valent organic group having 1 to 40 carbon atoms represented by W is a group obtained by removing p hydrogen atoms from a monovalent organic group having 1 to 40 carbon atoms. Examples of monovalent organic groups having 1 to 40 carbon atoms include a monovalent hydrocarbon group having 1 to 40 carbon atoms, a group (a) having a divalent heteroatom-containing linking group between the carbon atoms of the hydrocarbon group or at the terminal end of the hydrocarbon group, a group in which some or all of the hydrogen atoms of the hydrocarbon group or group (a) are replaced with a monovalent heteroatom-containing substituent, or combinations thereof.

[0018] Examples of monovalent hydrocarbon groups having 1 to 40 carbon atoms include monovalent linear hydrocarbon groups having 1 to 40 carbon atoms, monovalent alicyclic hydrocarbon groups having 3 to 40 carbon atoms, monovalent aromatic hydrocarbon groups having 6 to 40 carbon atoms, or combinations thereof.

[0019] Examples of monovalent chain hydrocarbon groups having 1 to 40 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, and t-butyl groups; alkenyl groups such as ethenyl, propenyl, and butenyl groups; and alkynyl groups such as ethynyl, propynyl, and butynyl groups.

[0020] Examples of monovalent alicyclic hydrocarbon groups having 3 to 40 carbon atoms include monocyclic cycloalkyl groups such as cyclopentyl and cyclohexyl groups; monocyclic cycloalkenyl groups such as cyclopropenyl, cyclopentenyl, and cyclohexenyl groups; polycyclic saturated hydrocarbon groups such as norbornyl, adamantyl, tricyclodecyl, pinanyl, caranyl, and bornanyl groups; and polycyclic unsaturated hydrocarbon groups such as norborneyl and tricyclodecenyl groups.

[0021] Examples of monovalent aromatic hydrocarbon groups having 6 to 40 carbon atoms include aryl groups such as phenyl, tolyl, xyl, naphthyl, anthracenyl, and pyrenyl groups; and aralkyl groups such as benzyl and phenethyl groups.

[0022] The organic groups in W preferably include -O-, -CO-, a cyclic structure, or a combination thereof. This combination also includes structures (heterocyclic structures) in which -O- or -CO- are incorporated as ring-forming parts within the cyclic structure.

[0023] The cyclic structure may be monocyclic, polycyclic, or a combination thereof. Furthermore, the cyclic structure may be alicyclic, aromatic, heterocyclic, or a combination thereof. In the case of a combination, the cyclic structures may be linked by chain structures, and two or more cyclic structures may form fused ring structures, bridged ring structures, or spiro-ring structures. Divalent heteroatom-containing linking groups may exist between the carbon atoms forming the skeleton of the cyclic or chain structure, and some or all of the hydrogen atoms on the carbon atoms of the cyclic or chain structure may be substituted with substituents.

[0024] As the above-mentioned alicyclic structure, a structure corresponding to the monovalent alicyclic hydrocarbon group having 3 to 40 carbon atoms can be suitably adopted.

[0025] As the above aromatic ring structure, a structure corresponding to a monovalent aromatic hydrocarbon group having 6 to 40 carbon atoms can be suitably adopted.

[0026] Examples of the above heterocyclic structures include aliphatic heterocyclic structures and aromatic heterocyclic structures. Examples of aliphatic heterocyclic structures include oxirane, tetrahydrofuran, tetrahydropyran, dioxolane, dioxane, aziridine, pyrrolidine, piperidine, piperazine, thiethane, thiolane, thian, morpholine, 1,2-oxathiolane, and 1,3-oxathiolane. Examples of aromatic heterocyclic structures include furan, benzofuran, pyrrole, pyrazole, triazine, thiophene, oxazole, isothiazole, and thiazine.

[0027] Heterocyclic structures include lactone structures, cyclic carbonate structures, sultone structures, cyclic imide structures, cyclic ketone structures, cyclic acetals, or combinations thereof.

[0028] As the above-mentioned chain-like structure, a structure corresponding to a monovalent chain-like hydrocarbon group having 1 to 40 carbon atoms can be suitably adopted.

[0029] The cyclic structure in W is preferably an alicyclic or aromatic ring structure, more preferably an alicyclic hydrocarbon structure having 5 to 12 carbon atoms or an aromatic hydrocarbon structure having 6 to 20 carbon atoms, and even more preferably cyclopentane, cyclohexane, norbornane, benzene, and naphthalene.

[0030] If the organic group in W includes an aromatic ring structure, the aromatic ring structure may have iodine atoms as substituents. The number of iodine atoms is preferably 1 to 3, and more preferably 1 or 2.

[0031] X - ga-SO ３ - If so, -SO in W ３ - Groups other than the fluorine atom bonded to the α-carbon of the sulfur atom (hereinafter also referred to as "group (α)") include monovalent organic groups having 1 to 20 carbon atoms, hydroxyl groups, sulfanyl groups, amino groups, nitro groups, halogen atoms other than fluorine atoms, etc.

[0032] As the monovalent organic group having 1 to 20 carbon atoms in group (α), groups corresponding to 1 to 20 carbon atoms can be suitably adopted from the monovalent organic groups having 1 to 40 carbon atoms shown in W.

[0033] Other halogen atoms besides the fluorine atom in group (α) include chlorine, bromine, and iodine atoms.

[0034] The organic acid anion of substructure (i) preferably has a structure represented by the following formula (Z1). (In formula (Z1), Cy １１ and Cy １２ These are, independently, substituted or unsubstituted cyclic structures. １２ If there are multiple Cy １２ They are either identical or different from each other. １２ and L １３ Each of these is independently a single-bonded, substituted, or unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms, a divalent heteroatom-containing linking group, or a combination thereof. １２ If there are multiple L １２They are either identical or different from each other. However, X - ga-SO ３ - If L １３ -SO ３ - A group other than a fluorine atom or a hydrogen atom is bonded to the α-carbon of the sulfur atom. z12 is an integer from 0 to 3. *, p and X - This is equivalent to equation (i) above.

[0035] In the above formula (Z1), Cy １１ and Cy １２ As the annular structure represented by , the annular structure shown in W can be suitably adopted.

[0036] L １２ and L １３ As the divalent hydrocarbon group having 1 to 10 carbon atoms in the above formula (i), a group obtained by removing one hydrogen atom from the monovalent hydrocarbon group having 1 to 40 carbon atoms shown in W of the above formula (i) corresponding to the group having 1 to 10 carbon atoms can be suitably adopted. １２ and L １３ The divalent hydrocarbon group having 1 to 10 carbon atoms in the compound is preferably a methanediyl group, a 1,1-ethanediyl group, a 1,2-ethanediyl group, a 1,3-propanediyl group, a 1,1-propanediyl group, a 2,2-propanediyl group, a 2-methyl-propane-1,1-diyl group, a 1,4-butanediyl group, or a 1,1-butanediyl group.

[0037] z12 is preferably an integer between 0 and 2, and more preferably 0 or 1.

[0038] In the above equation (i), Z ＋ The organic cation represented by is not particularly limited, and examples include onium cations containing elements such as S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, and Bi. Examples of onium cations include sulfonium cations, tetrahydrothiophenium cations, iodonium cations, phosphonium cations, diazonium cations, pyridinium cations, and ammonium cations.

[0039] Z ＋It is preferable that the cation is a radiation-sensitive onium cation. Examples of radiation-sensitive onium cations include sulfonium cations, tetrahydrothiophenium cations, and iodonium cations. Among these, radiation-sensitive sulfonium cations or radiation-sensitive iodonium cations are preferred, and radiation-sensitive sulfonium cations are more preferred.

[0040] Z ＋ Preferably, it is a sulfonium cation represented by the following formula (Q-1).

[0041]

[0042] In the above equation (Q-1), * and q are equivalent to those in the above equation (i).

[0043] In the above formula (Q-1), Ra1 and Ra2 each independently represent substituents. n1 represents an integer from 0 to 5, and if n1 is 2 or greater, multiple Ra1s may be the same or different. n2 represents an integer from 0 to 5, and if n2 is 2 or greater, multiple Ra2s may be the same or different. Ra3 represents a substituent. n3 represents an integer from 0 to 5, and if n3 is 2 or greater, multiple Ra3s may be the same or different. Ra1 and Ra2 may be linked to each other to form a ring. If n1 is 2 or greater, multiple Ra1s may be linked to each other to form a ring. If n2 is 2 or greater, multiple Ra2s may be linked to each other to form a ring.

[0044] Preferred substituents represented by Ra1, Ra2, and Ra3 are alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkyloxy groups, alkoxycarbonyl groups, alkylsulfonyl groups, hydroxyl groups, halogen atoms, and halogenated hydrocarbon groups.

[0045] The alkyl groups Ra1 and Ra2 may be linear or branched alkyl groups. Preferably, these alkyl groups have 1 to 10 carbon atoms, and examples include methyl, ethyl, n-propyl, i-propyl, n-butyl, 2-methylpropyl, 1-methylpropyl, t-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl groups. Of these, methyl, ethyl, n-butyl, and t-butyl groups are particularly preferred.

[0046] Examples of cycloalkyl groups for Ra1 and Ra2 include monocyclic or polycyclic cycloalkyl groups (preferably cycloalkyl groups having 3 to 20 carbon atoms), such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclododecanyl, cyclopentenyl, cyclohexenyl, and cyclooctadienyl groups. Of these, cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups are particularly preferred.

[0047] Examples of the alkyl groups of the alkoxy groups of Ra1 and Ra2 include those previously listed as alkyl groups of Ra1 and Ra2. Methoxy, ethoxy, n-propoxy, and n-butoxy groups are particularly preferred as alkoxy groups.

[0048] Examples of the cycloalkyl group portions of Ra1 and Ra2 include those previously listed as cycloalkyl groups of Ra1 and Ra2. Cyclopentyloxy and cyclohexyloxy groups are particularly preferred as these cycloalkyl groups.

[0049] Examples of the alkoxy carbonyl groups of Ra1 and Ra2 include those previously listed as alkoxy groups of Ra1 and Ra2. Methoxycarbonyl groups, ethoxycarbonyl groups, and n-butoxycarbonyl groups are particularly preferred as alkoxycarbonyl groups.

[0050] Examples of the alkyl group portion of the alkylsulfonyl groups of Ra1 and Ra2 include those previously listed as alkyl groups of Ra1 and Ra2. Similarly, examples of the cycloalkyl group portion of the cycloalkylsulfonyl groups of Ra1 and Ra2 include those previously listed as cycloalkyl groups of Ra1 and Ra2. Among these alkylsulfonyl groups or cycloalkylsulfonyl groups, methanesulfonyl, ethanesulfonyl, n-propanesulfonyl, n-butanesulfonyl, cyclopentanesulfonyl, and cyclohexanesulfonyl groups are particularly preferred.

[0051] Each of the Ra1 and Ra2 groups may have further substituents. Examples of such substituents include halogen atoms such as fluorine atoms (preferably fluorine atoms), hydroxyl groups, carboxyl groups, cyano groups, nitro groups, alkoxy groups, cycloalkyloxy groups, alkoxyalkyl groups, cycloalkyloxyalkyl groups, alkoxycarbonyl groups, cycloalkyloxycarbonyl groups, alkoxycarbonyloxy groups, and cycloalkyloxycarbonyloxy groups.

[0052] Examples of halogen atoms for Ra1 and Ra2 include fluorine, chlorine, bromine, and iodine atoms, with fluorine and iodine atoms being preferred.

[0053] As the halogenated hydrocarbon groups of Ra1 and Ra2, halogenated alkyl groups are preferred. The alkyl groups and halogen atoms constituting the halogenated alkyl groups are the same as those described above. Among these, fluorinated alkyl groups are preferred, and CF ３ This is preferable.

[0054] As described above, Ra1 and Ra2 may be linked to each other to form a ring (i.e., a heterocycle containing a sulfur atom). In this case, it is preferable that Ra1 and Ra2 are linked to each other to form a single bond or a divalent linking group. Examples of divalent linking groups include -COO-, -OCO-, -CO-, -O-, -S-, -SO-, and -SO ２-, an alkylene group, a cycloalkylene group, an alkenylene group, or a combination of two or more of these, and those having a total carbon number of 20 or less are preferred. When Ra1 and Ra2 are bonded to each other to form a ring, Ra1 and Ra2 are bonded to each other to form -COO-, -OCO-, -CO-, -O-, -S-, -SO-, -SO ２ - or a single bond. Among them, forming -O-, -S- or a single bond is more preferred, and forming a single bond is particularly preferred. In addition, when n1 is 2 or more, a plurality of Ra1 groups may be bonded to each other to form a ring, and when n2 is 2 or more, a plurality of Ra2 groups may be bonded to each other to form a ring. Examples of such a case include an embodiment in which two Ra1 groups are bonded to each other and form a naphthalene ring together with the benzene ring to which they are bonded.

[0055] Ra3 is preferably a fluorine atom, a group having one or more fluorine atoms, or an iodine atom. Examples of the group having a fluorine atom include groups obtained by substituting a fluorine atom into the alkyl group, cycloalkyl group, alkoxy group, cycloalkyloxy group, alkoxycarbonyl group and alkylsulfonyl group as Ra1 and Ra2. Among these, fluorinated alkyl groups are preferred, and CF ３ , C ２ F ５ , C ３ F ７ , C ４ F ９ , C ５ F １１ , C ６ F １３ , C ７ F １５ , C ８ F １７ , CH ２ CF ３ , CH ２ CH ２ CF ３ , CH ２ C ２ F ５ , CH ２ CH ２ C ２ F ５ , CH ２ C ３ F７ ,CH ２ CH ２ C ３ F ７ ,CH ２ C ４ F ９ and CH ２ CH ２ C ４ F ９ The following can be more preferably listed: CF ３ The following can be particularly preferred.

[0056] Ra3 is a fluorine atom, an iodine atom, or CF ３ It is preferable that it be a fluorine atom or an iodine atom.

[0057] n1 and n2 are each independently preferably integers between 0 and 3, and preferably integers between 0 and 2.

[0058] n3 is preferably an integer between 1 and 3, and more preferably 1 or 2.

[0059] (n1 + n2 + n3) is preferably an integer from 1 to 15, more preferably an integer from 1 to 9, even more preferably an integer from 2 to 6, and particularly preferably an integer from 3 to 6. When (n1 + n2 + n3) is 1, n3 = 1 and Ra3 is a fluorine atom, an iodine atom, or CF ３ It is preferable that (n1 + n2 + n3) is 2, then n1 = n3 = 1 and Ra1 and Ra3 are each independently a fluorine atom, an iodine atom, or CF ３ The combinations are as follows, and n3=2 and Ra3 is a fluorine atom, an iodine atom or CF ３ The following combinations are preferred. When (n1 + n2 + n3) is 3, n1 = n2 = n3 = 1 and Ra1 to Ra3 are each independently a fluorine atom, an iodine atom, or CF ３ The following combinations are preferred. When (n1 + n2 + n3) is 4, n1 = n3 = 2 and Ra1 and Ra3 are each independently a fluorine atom, an iodine atom or CF ３ The following combinations are preferred. When (n1 + n2 + n3) is 5, n1 = n2 = 1 and n3 = 3, and Ra1 to Ra3 are each independently a fluorine atom, an iodine atom, or CF ３The combination is such that n1=n2=2 and n3=1, and Ra1 to Ra3 are each independently a fluorine atom, an iodine atom, or CF ３ The combinations are such that n3=5 and each Ra3 is independently a fluorine atom, an iodine atom, or CF ３ The following combinations are preferred. When (n1 + n2 + n3) is 6, n1 = n2 = n3 = 2 and Ra1 to Ra3 are each independently a fluorine atom, an iodine atom, or CF ３ The combination is preferable.

[0060] In the above equation (i), Z ＋ This may be a diaryliodonium cation. The diaryliodonium cation preferably has one or more fluorine or iodine atoms. A phenyl group is preferred as the aryl group. A heteroaryl group may be used instead of the aryl group. As the heteroaryl group, a group obtained by removing one hydrogen atom from the aromatic heterocyclic structure shown in the cyclic structure of W in formula (i) above can be suitably adopted. The aryl group may have substituents represented by Ra1, Ra2, and Ra3 in formula (Q-1) above.

[0061] Specific examples of the sulfonium cation represented by the above formula (Q-1) include the structure represented by the following formula. In the following formula, the bonds with other structures of the polymer are omitted.

[0062]

[0063]

[0064]

[0065]

[0066] Specific examples of the iodonium cation mentioned above include structures represented by the following formula.

[0067] [D2] The polymer preferably contains repeating units having substructure (i) (hereinafter also referred to as "repeating unit (1)"), from the viewpoint of ease of introducing substructure (i).

[0068] The form in which the organic acid anion and organic cation constituting the substructure (i) in the repeating unit (1) are contained is not particularly limited, and the [D2] polymer may have the organic acid anion as a side chain portion, or it may have the organic cation as a side chain portion. Having as a side chain portion means that the corresponding organic acid anion or organic cation is bonded (covalently bonded) to the main chain as a side chain structure of the [D2] polymer. When the organic acid anion is bonded to the main chain as a side chain structure of the [D2] polymer, the organic cation is ionically bonded to the organic acid anion as its counterion (in formula (i) above, p=1 and q=0). On the other hand, when the organic cation is bonded to the main chain as a side chain structure of the [D2] polymer, the organic acid anion is ionically bonded to the organic cation as its counterion (in formula (i) above, p=0 and q=1).

[0069] [D2] The polymer preferably has repeating units (1) derived from a compound represented by the following formula (B1) (hereinafter also referred to as "repeating unit (1-B1)"), repeating units derived from a compound represented by the following formula (B2) (hereinafter also referred to as "repeating unit (1-B2)"), repeating units derived from a compound represented by the following formula (B3) (hereinafter also referred to as "repeating unit (1-B3)"), or repeating units derived from a compound represented by the following formula (B4) (hereinafter also referred to as "repeating unit (1-B4)").

[0070] (In the above formulas (B1) to (B4), X - This is equivalent to equation (i) above. R Ｂ Each of these is independently a hydrogen atom, a halogen atom, or a monovalent organic group having 1 to 20 carbon atoms. Ｂ Each of these is independently a single bond or a divalent linking group. Ｂ１ Each of these is independently a divalent organic group having 1 to 40 carbon atoms. However, X - ga-SO ３ - If W Ｂ１ -SO ３ -A group other than a fluorine atom or a hydrogen atom is bonded to the α-carbon of the sulfur atom. １ and L ２ Each of these is independently a single bond or a divalent linking group. Each of these is independently an aromatic ring. Z Ｂ１ ＋ These are, independently, organic cations. Ｂ２ X is a monovalent organic group having 1 to 40 carbon atoms. - ga-SO ３ - If W Ｂ２ -SO ３ - A group other than a fluorine atom or a hydrogen atom is bonded to the α-carbon of the sulfur atom. Ｂ２ ＋ These are, independently, monovalent organic cations.

[0071] In the above formulas (B1) to (B4), R Ｂ As the monovalent organic group having 1 to 20 carbon atoms represented by the above formula (i), the monovalent organic group having 1 to 20 carbon atoms in the W group (α) of the above formula (i) can be suitably adopted. Ｂ A hydrogen atom or a methyl group is preferred as the element.

[0072] In the above formulas (B1) to (B2) and formula (B4), L Ｂ As the divalent linking group represented by , for example, a divalent hydrocarbon group, a divalent heteroatom-containing linking group, or a group combining these can be suitably adopted.

[0073] L Ｂ In formula (i) above, the divalent hydrocarbon group can preferably be one obtained by removing one hydrogen atom from the monovalent hydrocarbon group with 1 to 40 carbon atoms, as shown in W, which corresponds to the group with 1 to 20 carbon atoms. Ｂ The divalent hydrocarbon groups in this compound are preferably methanediyl, ethanediyl, benzenediyl, and naphthalenediyl groups, with benzenediyl being more preferred.

[0074] L Ｂ As for divalent heteroatom-containing linking groups in this, ＊-COO- is preferred. * indicates the bond on the carbon-carbon double bond side.

[0075] In the above formulas (B1), (B3) to (B4), W Ｂ１ As the divalent organic group having 1 to 40 carbon atoms represented by the above formula (i), a group obtained by removing one hydrogen atom from the monovalent organic group having 1 to 40 carbon atoms shown in W of the above formula (i) can be suitably adopted. In the above formula (B1), W Ｂ１ It is preferable that the structure is represented by the above formula (Z1).

[0076] In the above formulas (B3) to (B4), W Ｂ１ It is preferable that the A-side terminal has an ester bond, ether bond, amide bond, or sulfonamide bond, more preferably an ester bond or ether bond, and even more preferably an ester bond.

[0077] In the above formulas (B3) to (B4), L １ and L ２ As a divalent linking group represented by , L Ｂ A divalent linking group represented by L can be suitably adopted. １ and L ２ Examples include single bonds, alkylene groups with 1 to 5 carbon atoms, -O-, -S-, or -NR １１ - (R １１ is preferably a hydrogen atom or a monovalent hydrocarbon group, more preferably a single bond, -O-, or -S-, and even more preferably a single bond.

[0078] In formulas (B3) to (B4) above, the aromatic ring represented by A can preferably be the aromatic ring structure or aromatic heterocyclic structure shown as the cyclic structure of W in formula (i) above. Among these, it is preferably a benzene ring, a naphthalene ring, anthracene ring, or a furan ring, more preferably a benzene ring or a naphthalene ring, and even more preferably a naphthalene ring.

[0079] In the above formula (B2), W Ｂ２As the monovalent organic group having 1 to 40 carbon atoms represented by the above formula (i), the monovalent organic group having 1 to 40 carbon atoms shown in W can be suitably adopted. In the above formula (B2), W Ｂ２ It is preferable that the structure is represented by the above formula (Z1).

[0080] In the above formulas (B1) and (B3), Z Ｂ１ ＋ The organic cation represented by is Z of formula (i) above. ＋ This allows for the suitability of employing an organic cation (corresponding to q=0).

[0081] In the above formulas (B2) and (B4), Z Ｂ２ ＋ As a monovalent organic cation represented by the above formula (i), Z ＋ A structure obtained by removing one hydrogen atom from the organic cation represented by (corresponding to q=1) can be suitably adopted.

[0082] Specific examples of organic acid anions of the compound represented by the above formula (B1) include, but are not limited to, the structure represented by the following formula. In the following formula, R Ｂ This is equivalent to the above formula (B1). X - This is equivalent to equation (i) above.

[0083]

[0084]

[0085] As the organic acid cation of the compound represented by formula (B1) above, a sulfonium cation represented by formula (Q-1) above, or a diaryliodonium cation can be suitably used.

[0086] A specific example of the organic acid anion of the compound represented by formula (B2) above is H from the structure of the organic acid anion of the compound represented by formula (B1) above. ２ C = C(R Ｂ )-or H ２ C = C(R Ｂ In addition to the structure excluding )-COO-, other examples include the structure represented by the following formula. In the following formula, X - This is equivalent to equation (i) above.

[0087]

[0088]

[0089] As the organic acid cation of the compound represented by formula (B2) above, H is attached to one benzene ring of the sulfonium cation represented by formula (Q-1) above. ２ C = C(R Ｂ )-or H ２ C = C(R Ｂ A structure in which )-COO- is bonded, or one aryl group of diaryliodonium cation is bonded to H ２ C = C(R Ｂ )-or H ２ C = C(R Ｂ A structure in which )-COO- is bonded can be suitably adopted. Ｂ This is equivalent to equation (i) above.

[0090] Specific examples of organic acid anions of the compounds represented by formulas (B3) and (B4) above include, but are not limited to, the structures represented by the following formulas. In the following formulas, R Ｂ Although all of them are hydrogen atoms, R is in the above formula (B3). Ｂ The groups shown can be suitably adopted.

[0091]

[0092]

[0093] As the organic acid cation of the compound represented by formula (B3) above, a sulfonium cation represented by formula (Q-1) above, or a diaryliodonium cation can be suitably used.

[0094] As the organic acid cation of the compound represented by formula (B4) above, H is attached to one benzene ring of the sulfonium cation represented by formula (Q-1) above. ２ C = C(R Ｂ )-or H ２ C = C(R Ｂ A structure in which )-COO- is bonded, or one aryl group of diaryliodonium cation is bonded to H ２ C = C(R Ｂ )-or H２ C = C(R Ｂ A structure in which )-COO- is bonded can be suitably adopted. Ｂ This is equivalent to equation (i) above.

[0095] [D2] The lower limit of the content of repeating unit (1) in the total repeating units constituting the polymer (the total content if there are multiple types) is preferably 0.5 mol%, more preferably 1 mol%, and even more preferably 1.5 mol%. The upper limit of the above content is preferably 40 mol%, more preferably 30 mol%, and even more preferably 20 mol%.

[0096] [D2] The polymer preferably contains repeating units having the above group (X) (hereinafter also referred to as "repeating unit (2)") as a form of containing the above group (X). The above group (X) is more preferably at least one monovalent group selected from the group consisting of the group represented by formula (2-1), the group represented by formula (2-2), the group represented by formula (2-3), the group represented by formula (2-4), the group represented by formula (2-5), the group represented by formula (2-6), the group represented by formula (2-7), and the group represented by formula (2-8). The repeating unit (2) is preferably a repeating unit derived from a compound represented by any of the following formulas (G-1) to (G-3). The [D2] polymer may have one or more types of repeating units (2).

[0097] (In formulas (G-1) to (G-3), R ３ Each of these is independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. ３ Each of these is independently a single bond or a divalent linking group. ４ Each of these is independently the above-mentioned group (X). １ , L ２ And A is equivalent to the above formula (B3).

[0098] In the above formulas (G-1) to (G-3), R ３As the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the above formula (i), the monovalent hydrocarbon group having 1 to 20 carbon atoms shown in W can be suitably adopted. ３ It is preferable that this is a hydrogen atom or a methyl group.

[0099] In the above formulas (G-1) to (G-3), L ３ The divalent linking group represented by is L in formula (B1) above. Ｂ Examples include divalent linking groups represented by L. ３ As COO ＊ ( ＊ R ４ The bond is a methanediyl group, ethanediyl group, benzenediyl group, naphthalenediyl group, or a combination thereof, or a single bond is preferred.

[0100] In the above formulas (G-1) to (G-3), R ４ The group having a phenolic hydroxyl group represented by is preferably the group represented by the following formula (P). (In formula (P), Ar is a substituted or unsubstituted aromatic ring. c is an integer from 1 to 3. * is L) ３ (This is a combination of the two.)

[0101] As the aromatic ring in Ar, the aromatic ring structure shown as the cyclic structure of W in formula (i) above, or the aromatic heterocyclic structure can be suitably adopted. Among these, the benzene ring and the naphthalene ring are preferred as the aromatic ring of Ar, with the benzene ring being more preferred.

[0102] c is preferably 1 or 2.

[0103] In the above equations (2-1) to (2-3) and (2-7), R ８ , R ９ , R １０ , R １１ , R １２ and R １３ (Hereinafter referred to as “R ８ ~R １３It is also written as ). As a monovalent organic group having 1 to 20 carbon atoms represented by ), the group corresponding to 1 to 20 carbon atoms from among the monovalent organic groups having 1 to 40 carbon atoms shown in W of formula (i) above can be suitably adopted.

[0104] R ８ ~R １３ Each of these is preferably a hydrogen atom or a methyl group, and more preferably both are hydrogen atoms.

[0105] In formula (2-2) above, the ring structure with 3 to 20 members that is formed together with the two carbon atoms in the formula represented by Cy can preferably be a ring structure corresponding to a monovalent alicyclic hydrocarbon having 3 to 20 carbon atoms as shown in W in formula (i) above. As Cy, a cycloalkane ring having 5 to 10 carbon atoms is preferred, and a cyclopentane ring, a cyclohexane ring, or a cycloheptane ring is more preferred.

[0106] In the above equations (2-1) to (2-8), R ７ As a divalent organic group having 1 to 20 carbon atoms represented by the above R ８ ~R １３ A monovalent organic group having 1 to 20 carbon atoms, represented by [the formula shown], can be suitably used, with one hydrogen atom removed.

[0107] R ７ Preferred linkages include single bonds, divalent hydrocarbon groups having 1 to 10 carbon atoms, or combinations of divalent hydrocarbon groups having 1 to 10 carbon atoms and divalent heteroatom-containing linkages. Preferred divalent hydrocarbon groups having 1 to 10 carbon atoms include methylene groups and ethanediyl groups. Preferred divalent heteroatom-containing linkages include -O-, -CO-, or combinations thereof.

[0108] Specific examples of compounds represented by the above formulas (G-1) to (G-3) that give the repeating unit (2) include, for example, the compounds represented by the following formulas.

[0109]

[0110]

[0111] In the above formula, R ３This is equivalent to equations (G-1) to (G-3) above.

[0112] When the [D2] polymer contains repeating units (2), the lower limit of the content of repeating units (2) to the total repeating units constituting the [D2] polymer (total content if multiple types are included) is preferably 40 mol%, more preferably 50 mol%, and even more preferably 60 mol%. The upper limit of the above content is preferably 98 mol%, more preferably 95 mol%, and even more preferably 90 mol%. By setting the content of repeating units (2) within the above range, high levels of solvent resistance and resist pattern rectangularity can be achieved.

[0113] The [D2] polymer may have other repeating units (different from repeating units (1) or (2)), such as repeating units containing structures that generate acid upon exposure, such as an onium salt structure containing a sulfonate anion and a sulfonium cation, an onium salt structure containing a sulfonate anion and an iodonium cation, repeating units having a fluorine atom or an iodine atom, repeating units having an acid-dissociable group, repeating units having a hydroxyl group, etc. An "acid-dissociable group" is a group that substitutes a hydrogen atom, such as a carboxyl group, a phenolic hydroxyl group, an alcoholic hydroxyl group, or a sulfo group, and dissociates upon the action of an acid. Examples of repeating units having an acid-dissociable group include a repeating unit having a tertiary alkyl ester moiety, a repeating unit having a structure in which an aromatic group and an aliphatic group are bonded to the secondary carbon constituting the secondary alkyl ester moiety, a repeating unit having a structure in which the hydrogen atom of a phenolic hydroxyl group is substituted with a tertiary alkyl group, and a repeating unit having an acetal bond. The [D2] polymer may contain one or more of these other repeating units. If the [D2] polymer contains other repeating units, the lower limit of the proportion of other repeating units to the total repeating units constituting the [D2] polymer (the total proportion if there are multiple types) may be 2 mol%, 5 mol%, or 8 mol%. The upper limit of the above proportion may be 80 mol%, 70 mol%, or 60 mol%.

[0114] <[A] Polymer> The [A] polymer is a polymer that does not contain substructure (i). The [A] polymer may have the same structure as the [D2] polymer, except that it does not contain substructure (i). That is, when the [A] polymer is an addition polymerization reactant, it may have at least one repeating unit selected from the group consisting of the above repeating unit (2) and other repeating units. The content ratio of each repeating unit is determined according to the ratio of the content ratios of each repeating unit other than repeating unit (1) in the [D2] polymerization, and a value converted so that the sum of the content ratios of each repeating unit is 100 mol% can preferably be adopted.

[0115] [A] The polymer may be an addition-condensation reactant. When [A] is an addition-condensation reactant, the polymer may have repeating units represented by the following formula (J) (hereinafter also referred to as "repeating unit (3)"). The polymer [A] may have one or more repeating units (3).

[0116] (In formula (J), Ar １ R is a divalent group having an aromatic ring with 5 to 40 carbon atoms. ０ (This refers to a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms.)

[0117] In the above formula (J), Ar １ As aromatic rings with 5 to 40 members in the above formula (i), the aromatic ring structure shown as the cyclic structure of W and the aromatic heterocyclic structure can be suitably adopted. Among them, Ar １ The aromatic rings are preferably benzene rings and naphthalene rings, preferably pyrene rings and fluorene rings, and more preferably benzene rings and naphthalene rings.

[0118] In the above formula (1), Ar １ As a divalent group having an aromatic ring with 5 to 40 carbon atoms represented by the above Ar １ Preferred examples include groups obtained by removing two hydrogen atoms from an aromatic ring having 5 to 40 carbon atoms.

[0119] Ar １The divalent group preferably has a substituent. Preferred substituents are hydroxyl groups, alkyl groups, and groups represented by formulas (2-1) to (2-8) above. Preferred alkyl groups are methyl groups and ethyl groups.

[0120] In the above formula (J), R ０ As the monovalent organic group having 1 to 20 carbon atoms represented by the above formula (i), groups corresponding to 1 to 20 carbon atoms can be suitably adopted from among the monovalent organic groups having 1 to 40 carbon atoms shown in W of formula (i) above. ０ Preferred elements include hydrogen atoms, benzene rings, and naphthalene rings.

[0121] Specific examples of repeating units (3) include structures represented by the following formula.

[0122]

[0123] [A] The content ratio of the above repeating unit (3) to the total repeating units constituting the polymer (the total content ratio if there are multiple types) may be 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, or 100 mol%.

[0124] Regardless of whether the polymer is a [D2] polymer or an [A] polymer, the lower limit of the weight-average molecular weight (Mw) is preferably 2000, more preferably 3000, and even more preferably 4000. The upper limit of the above molecular weight is preferably 12000, more preferably 9000, and even more preferably 7000. The method for measuring the weight-average molecular weight is as described in the examples.

[0125] Regardless of whether the polymer is a [D2] polymer or an [A] polymer, the lower limit of the number average molecular weight (Mn) is preferably 1000, more preferably 2000, and even more preferably 3000. The upper limit of the above molecular weight is preferably 8000, more preferably 6000, and even more preferably 4500. The method for measuring the number average molecular weight is as described in the examples.

[0126] The content of the [D2] polymer or [A] polymer in the components other than the [B] solvent in the resist underlayer film forming composition may be 40% by mass or more, 50% by mass, 60% by mass, 70% by mass, 80% by mass, 90% by mass, or 100% by mass.

[0127] [Method for synthesizing polymers] Polymers can be synthesized by radical polymerization, ionic polymerization, polycondensation, polyaddition, addition condensation, etc., depending on the type of monomer. For example, when synthesizing the [D2] polymer or the [A] polymer by radical polymerization, the monomers that give each repeating unit can be synthesized by polymerizing them in a suitable solvent using a radical polymerization initiator, etc. When synthesizing the [A] polymer by addition condensation, preferably in an inert gas atmosphere such as a nitrogen gas atmosphere, Ar １ It can be synthesized by reacting a precursor compound that gives the compound with an aldehyde. An acid catalyst may be added during the addition condensation. The acid catalyst is not particularly limited, and known inorganic and organic acids can be used. After the reaction, separation, purification, washing, drying, etc. may be carried out as appropriate.

[0128] The solvent used in the polymerization described above can preferably be the solvent [B] described later. These solvents used in polymerization may be used individually or in combination of two or more.

[0129] The reaction temperature in the polymerization described above is usually 40°C to 150°C, with 50°C to 120°C being preferred. The reaction time is usually 1 hour to 48 hours, with 1 hour to 24 hours being preferred.

[0130] <[D1] Compounds> [D1] compounds are compounds that have a substructure (i). Unlike [D2] polymers, which incorporate substructure (i) as a side chain structure, [D1] compounds have a structure that is free from the polymerization chain. In other words, [D1] compounds have a smaller molecular weight than [D2] polymers and do not have repeating units.

[0131] [D1] The compound is preferably a compound represented by the following formula (A) having an organic acid anion and an organic cation. (In the above formula (A), X - This is equivalent to equation (i) above. W Ａ X is a monovalent organic group having 1 to 40 carbon atoms. - ga-SO ３ - If W Ａ -SO ３ - A group other than a fluorine atom or a hydrogen atom is bonded to the α-carbon of the sulfur atom. Ａ ＋ (This is an organic cation.)

[0132] In the above formula (A), W Ａ As the monovalent organic group having 1 to 40 carbon atoms represented by the above formula (i), the monovalent organic group having 1 to 40 carbon atoms shown in W can be suitably adopted.

[0133] X - ga-SO ３ - If W Ａ -SO ３ - As a group other than the fluorine atom bonded to the α-carbon of the sulfur atom, the group (α) shown in W of the above formula (i) can be suitably adopted.

[0134] [D1] Organic acid anion of the compound (in formula (A) above, W Ａ -X - As a specific example of the corresponding (corresponding to), a specific example of an organic acid anion of the compound represented by the above formula (B2) can be suitably adopted.

[0135] Z Ａ ＋ As an organic cation represented by Z, ＋ An organic cation represented by (corresponding to q=0) can be suitably used.

[0136] [D1] Specific examples of the organic cation of the compound include the sulfonium cation and diaryliodonium cation represented by the above formula (Q-1).

[0137] The lower limit of the content of compound [D1] is preferably 0.5 parts by mass, more preferably 1 part by mass, and still more preferably 1.5 parts by mass, per 100 parts by mass of polymer [A]. The upper limit of the above content is preferably 15 parts by mass, more preferably 10 parts by mass, and still more preferably 8 parts by mass.

[0138] <[B] Solvent> The [B] solvent is not particularly limited as long as it can dissolve or disperse the [A] polymer and any optional components contained therein as needed.

[0139] [B] Examples of solvents include hydrocarbon solvents, ester solvents, alcohol solvents, ketone solvents, ether solvents, and nitrogen-containing solvents. [B] Solvents can be used individually or in combination of two or more.

[0140] Examples of hydrocarbon solvents include aliphatic hydrocarbon solvents such as n-pentane, n-hexane, and cyclohexane, and aromatic hydrocarbon solvents such as benzene, toluene, and xylene.

[0141] Examples of ester solvents include carbonate solvents such as diethyl carbonate, acetic acid monoester solvents such as methyl acetate and ethyl acetate, lactone solvents such as γ-butyrolactone, and polyhydric alcohol partial ether carboxylate solvents such as diethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate.

[0142] Examples of alcohol-based solvents include monoalcohol solvents such as methanol, ethanol, n-propanol, 4-methyl-2-pentanol, and 2,2-dimethyl-1-propanol, and polyhydric alcohol solvents such as ethylene glycol and 1,2-propylene glycol. In this embodiment, alcohol acid ester solvents such as methyl lactate, ethyl lactate, propyl lactate, butyl lactate, methyl 2-hydroxyisobutyrate, isopropyl 2-hydroxyisobutyrate, isobutyl 2-hydroxyisobutyrate, and n-butyl 2-hydroxyisobutyrate are also included in the alcohol-based solvents.

[0143] Examples of ketone solvents include linear ketone solvents such as methyl ethyl ketone, 4-methyl-2-pentanone (methyl isobutyl ketone), and 2-heptanone, as well as cyclic ketone solvents such as cyclohexanone.

[0144] Examples of ether-based solvents include linear ether solvents such as n-butyl ether, polyhydric alcohol ether solvents such as cyclic ether solvents such as tetrahydrofuran, and polyhydric alcohol partial ether solvents such as diethylene glycol monomethyl ether and propylene glycol monomethyl ether.

[0145] Examples of nitrogen-containing solvents include linear nitrogen-containing solvents such as N,N-dimethylacetamide and cyclic nitrogen-containing solvents such as N-methylpyrrolidone.

[0146] [B] As solvents, ether-based solvents, ester-based solvents, and alcohol-based solvents are preferred, polyhydric alcohol partial ether-based solvents, polyhydric alcohol partial ether carboxylate-based solvents, and alcohol acid ester-based solvents are more preferred, and propylene glycol monomethyl ether, propylene glycol acetate monomethyl ether, and methyl 2-hydroxyisobutyrate are even more preferred.

[0147] [Optional Components] The resist underlayer film forming composition may contain optional components as long as they do not impair the effects of the present invention. Examples of optional components include crosslinking agents, acid generators (different from [D1] compounds and [D2] polymers), photoradical generators, base generators, dehydrating agents, acid diffusion control agents, surfactants, and defoaming agents. Specific examples of base generators include, for example, "U-CAT (registered trademark) SA1", "U-CAT (registered trademark) SA102", "U-CAT (registered trademark) SA102-50", "U-CAT (registered trademark) SA106", "U-CAT (registered trademark) SA112", "U-CAT (registered trademark) SA506", "U-CAT (registered trademark) SA603", "U-CAT (registered trademark) 1000", "U-CAT (registered trademark) 1102", "U-CAT (registered trademark) 2000", "U-CAT (registered trademark) 2024", "U-CAT (registered trademark) 2026", "U-CAT (registered trademark) 2030", "U-CAT (registered trademark) Examples include "Trademark 2110", "U-CAT (Registered Trademark) 2313", "U-CAT (Registered Trademark) 651M", "U-CAT (Registered Trademark) 660M", "U-CAT (Registered Trademark) 18X", "TMED", "U-CAT (Registered Trademark) 201G", "U-CAT (Registered Trademark) 202", "U-CAT (Registered Trademark) 420A", "U-CAT (Registered Trademark) 130", "U-CAT (Registered Trademark) 891", "POLYCAT (Registered Trademark) 8", "POLYCAT (Registered Trademark) 9", "POLYCAT (Registered Trademark) 12", and "POLYCAT (Registered Trademark) 41" (all are product names, manufactured by Sunapro Co., Ltd.). As for defoaming agents, known defoaming agents can be used, including alcohol defoaming agents, phosphate ester defoaming agents, fatty acid ester defoaming agents, polyether defoaming agents, and silicone defoaming agents. Examples of fatty acid ester defoaming agents include methyl laurate, methyl palmitate, methyl stearate, propyl butyrate, butyl butyrate, ethyl isovalerate, and isobutyl propionate, with propyl butyrate and butyl butyrate being preferred. Ketone solvents such as 2-heptanone may also be used as defoaming agents. Optional components can be used individually or in combination of two or more. The content ratio of the optional components in the resist underlayer film forming composition can be appropriately determined depending on the type of optional component.

[0148] [Method for preparing a composition for forming a resist underlayer film] The resist underlayer film forming composition can be prepared by mixing [A] polymer, [B] solvent, and optionally any other components in a predetermined ratio, and preferably by filtering the resulting mixture through a membrane filter with a pore size of 0.5 μm or less.

[0149] 《Method for Manufacturing a Semiconductor Substrate》 The method for manufacturing the semiconductor substrate includes a step of directly or indirectly coating a resist underlayer film forming composition onto a substrate (hereinafter also referred to as the "resist underlayer film forming composition coating step"), a step of forming a resist film on the resist underlayer film formed by the resist underlayer film forming composition coating step (hereinafter also referred to as the "resist film forming step"), a step of exposing the resist film with radiation (hereinafter also referred to as the "exposure step"), and a step of developing at least the exposed resist film (hereinafter also referred to as the "development step").

[0150] According to the semiconductor substrate manufacturing method, by using a predetermined resist underlayer film formation composition in the coating step, a resist underlayer film with excellent resist pattern rectangularity and pattern peeling suppression can be formed, thereby enabling the manufacture of a semiconductor substrate with a good pattern shape.

[0151] The method for manufacturing the semiconductor substrate may further include, if necessary, a step of forming an organic underlayer film directly or indirectly on the substrate before the resist underlayer film formation composition coating step (hereinafter also referred to as the "organic underlayer film formation step").

[0152] The method for manufacturing the semiconductor substrate may further include, if necessary, a step of forming a silicon-containing film on the substrate directly or indirectly (hereinafter also referred to as the "silicon-containing film formation step") prior to the resist underlayer film formation composition coating step.

[0153] The following describes each step when the optional steps of forming an organic underlayer film and forming a silicon-containing film are included.

[0154] [Organic Underlayer Formation Process] In this process, an organic underlayer is formed directly or indirectly on the substrate before the resist underlayer formation composition coating process described above. This process is optional. Through this process, an organic underlayer is formed directly or indirectly on the substrate.

[0155] Examples of substrates include insulating films such as silicon oxide, silicon nitride, silicon oxynitride, and polysiloxane, as well as resin substrates. Furthermore, the substrate may be one that has been patterned with features such as wiring trenches and plug grooves (vias).

[0156] An organic underlayer can be formed by coating with an organic underlayer-forming composition. Methods for forming an organic underlayer by coating with an organic underlayer-forming composition include, for example, directly or indirectly coating a substrate with the composition and then curing the resulting coating by heating or exposure. Examples of organic underlayer-forming compositions include JSR Corporation's "HM8006". The heating and exposure conditions can be appropriately determined depending on the type of organic underlayer-forming composition used.

[0157] Examples of cases where an organic underlayer film is indirectly formed on a substrate include forming the organic underlayer film on a low-dielectric insulating film formed on the substrate.

[0158] [Silicon-containing film formation process] In this process, a silicon-containing film is formed on the substrate either directly or indirectly.

[0159] As the substrate, the substrate exemplified in the organic underlayer film formation process described above can be suitably used.

[0160] Silicon-containing films can be formed by coating with a silicon-containing film-forming composition, chemical vapor deposition (CVD), atomic layer deposition (ALD), etc. Methods for forming silicon-containing films by coating with a silicon-containing film-forming composition include, for example, directly or indirectly coating a substrate with the silicon-containing film-forming composition and then curing the resulting coating by exposure and / or heating. Commercially available silicon-containing film-forming compositions include, for example, "NFC SOG01," "NFC SOG04," and "NFC SOG080" (all from JSR Corporation). Silicon oxide films, silicon nitride films, silicon oxidizite films, and amorphous silicon films can be formed by chemical vapor deposition (CVD) or atomic layer deposition (ALD). Heating and exposure conditions can be appropriately determined depending on the type of silicon-containing film-forming composition used.

[0161] Examples of cases where a silicon-containing film is indirectly formed on a substrate include forming a silicon-containing film on a low-dielectric insulating film or an organic underlayer film formed on the substrate.

[0162] [Coating Process for Resist Underlayer Formation Composition] In this process, the resist underlayer formation composition is coated onto the silicon-containing film formed on the substrate. The coating method for the resist underlayer formation composition is not particularly limited and can be carried out by any suitable method, such as rotary coating, casting coating, or roll coating. A coating film is formed as a result, and the resist underlayer is formed by the volatilization of the solvent [B].

[0163] Furthermore, if the resist underlayer film formation composition is applied directly to the substrate, the above-mentioned organic underlayer film formation step and silicon-containing film formation step may be omitted.

[0164] Next, the coating film formed by the above coating process is heated. Heating the coating film promotes the formation of the resist underlayer film. More specifically, heating the coating film promotes the volatilization of solvent [B], etc.

[0165] The above-mentioned coating film may be heated in an atmospheric environment or in a nitrogen atmosphere. The lower limit of the heating temperature is preferably 100°C, more preferably 150°C, and even more preferably 180°C. The upper limit of the heating temperature is preferably 400°C, more preferably 350°C, and even more preferably 280°C. The lower limit of the heating time is preferably 15 seconds, more preferably 30 seconds. The upper limit of the heating time is preferably 1,200 seconds, and even more preferably 600 seconds.

[0166] The lower limit of the film thickness (average thickness) of the resist underlayer film formed is preferably 0.5 nm, more preferably 1 nm, and even more preferably 2 nm. The upper limit of the average thickness is preferably 15 nm, more preferably 12 nm, even more preferably 8 nm, and particularly preferably 5 nm. The method for measuring the average thickness is as described in the examples.

[0167] [Resist Film Formation Process] In this process, a resist film is formed on the resist underlayer film formed by the resist underlayer film forming composition coating process described above. The resist film is preferably formed using the resist film forming composition. The resist film may be either a coated film or a deposited film, but it is preferably a coated film. There are no particular limitations on the coating method of the resist film forming composition, and examples include rotary coating.

[0168] Examples of resist film-forming compositions used in this process include positive or negative type chemically amplified resist compositions containing a radiation-sensitive acid generator, positive type resist compositions containing an alkali-soluble resin and a quinone diazide-based photosensitive agent, negative type resist compositions containing an alkali-soluble resin and a crosslinking agent, and metal-containing resist film-forming compositions containing metals such as tin, zirconium, and hafnium. Among these, compositions subjected to exposure to extreme ultraviolet light are preferred as resist film-forming compositions, and positive or negative type chemically amplified resist compositions containing a radiation-sensitive acid generator, and metal-containing resist compositions containing metals such as tin, zirconium, and hafnium can be suitably used.

[0169] The above-mentioned resist film preferably contains a metal. Such a metal-containing resist film is preferably formed using a metal-containing resist film forming composition.

[0170] (Composition for forming metal-containing resist films) The composition for forming metal-containing resist films contains a metal-containing compound (hereinafter also referred to as "metal-containing compound (A)") and a solvent (hereinafter also referred to as "solvent (F)"), and it is preferable that the content ratio of the metal-containing compound (A) to the components other than solvent (F) in the above metal-containing resist film forming composition is 50% by mass or more. The above metal-containing resist film forming composition may further contain other components.

[0171] (Metal-containing compound (A)) Metal-containing compound (A) is a compound containing metal atoms. Metal-containing compound (A) can be used alone or in combination of two or more types. Furthermore, the metal atoms constituting metal-containing compound (A) can be used alone or in combination of two or more types. Here, "metal atom" is a concept that includes metalloids, namely boron, silicon, germanium, arsenic, antimony, and tellurium.

[0172] The metal atoms constituting the metal-containing compound (A) are not particularly limited, and examples include metal atoms from groups 3 to 16. Specific examples of the above metal atoms include, for example, group 4 metal atoms such as titanium, zirconium, and hafnium; group 5 metal atoms such as tantalum; group 6 metal atoms such as chromium and tungsten; group 8 metal atoms such as iron and ruthenium; group 9 metal atoms such as cobalt; group 10 metal atoms such as nickel; group 11 metal atoms such as copper; group 12 metal atoms such as zinc, cadmium, and mercury; group 13 metal atoms such as boron, aluminum, gallium, indium, and thallium; group 14 metal atoms such as germanium, tin, and lead; group 15 metal atoms such as antimony and bismuth; and group 16 metal atoms such as tellurium.

[0173] The metal atoms constituting the metal-containing compound (A) may include a first metal atom belonging to Group 4, Group 12, or Group 14 of the periodic table, and belonging to Period 4, Period 5, or Period 6. That is, the metal atoms may include at least one of titanium, zirconium, hafnium, zinc, cadmium, mercury, germanium, tin, and lead. In this way, the inclusion of a first metal atom in the metal-containing compound (A) promotes the emission of secondary electrons in the exposed area of ​​the resist film and the change in the solubility of the metal-containing compound (A) in the developer due to these secondary electrons. As a result, the rectangularity of the pattern can be improved. Tin or zirconium is preferred as the first metal atom.

[0174] The metal-containing compound (A) preferably further contains atoms other than metal atoms. Examples of these other atoms include carbon atoms, hydrogen atoms, oxygen atoms, nitrogen atoms, phosphorus atoms, sulfur atoms, halogen atoms, etc., with carbon atoms, hydrogen atoms, and oxygen atoms being preferred among these. The other atoms in the metal-containing compound (A) can be used individually or in combination of two or more types.

[0175] The lower limit of the content of the metal-containing compound (A) in the metal-containing resist film-forming composition, calculated on a solid content basis, is preferably 70% by mass, more preferably 90% by mass, and even more preferably 95% by mass. The above content may also be 100% by mass. Here, the solid content in the metal-containing resist film-forming composition refers to components other than the solvent (F) described later.

[0176] (Method for synthesizing metal-containing compound (A)) Metal-containing compound (A) can be obtained, for example, by performing a hydrolysis condensation reaction, ligand exchange reaction, etc., on a metal compound having a metal atom and a hydrolyzable group, a hydrolysate of this metal compound, a hydrolysis condensate of the above metal compound, or a combination thereof. The above metal compounds can be used individually or in combination of two or more.

[0177] The metal-containing compound (A) is preferably derived from a metal compound having a metal atom and a hydrolyzable group represented by the following formula (4) (hereinafter also referred to as "metal compound precursor (1)"). By using such a metal compound precursor (1), a stable metal-containing compound (A) can be obtained.

[0178] In the above formula (4), M is a metal atom. Ａ is a ligand or a monovalent organic group having 1 to 20 carbon atoms. a1 is an integer from 0 to 6. If a1 is 2 or more, multiple L １ Q may be the same or different. Q is a monovalent hydrolyzable group. b1 is an integer from 2 to 6. Multiple Qs may be the same or different. Note that L Ａ This is a ligand or organic group that does not correspond to Q.

[0179] The metal atom represented by M is preferably a metal atom of Group 14, and more preferably tin.

[0180] The hydrolyzable group represented by Q can be appropriately changed in accordance with the metal atom represented by M, but examples include substituted or unsubstituted ethynyl groups, halogen atoms, alkoxy groups, alkylcarbonyloxy groups, substituted or unsubstituted amino groups, etc.

[0181] The substituents in the substituted or unsubstituted ethynyl group and the substituted or unsubstituted amino group represented by Q are preferably monovalent hydrocarbon groups having 1 to 20 carbon atoms, more preferably linear hydrocarbon groups, and even more preferably alkyl groups.

[0182] Examples of halogen atoms represented by Q include fluorine, chlorine, bromine, and iodine atoms. Among these, chlorine atoms are preferred.

[0183] Examples of alkoxy groups represented by Q include methoxy, ethoxy, n-propoxy, i-propoxy, and n-butoxy groups. Among these, ethoxy, i-propoxy, and n-butoxy groups are preferred.

[0184] Examples of alkylcarbonyloxy groups represented by Q include acetoxy group, ethylcarbonyloxy group, propylcarbonyloxy group, n-butylcarbonyloxy group, t-butylcarbonyloxy group, t-amylcarbonyloxy group, n-hexylcarbonyloxy group, and n-octylcarbonyloxy group. Among these, the acetoxy group is preferred.

[0185] Examples of substituted or unsubstituted amino groups represented by Q include amino groups, methylamino groups, dimethylamino groups, diethylamino groups, and dipropylamino groups. Among these, dimethylamino groups and diethylamino groups are preferred.

[0186] The following describes preferred combinations of a metal atom represented by M and a hydrolyzable group represented by Q. When the metal atom represented by M is tin, the hydrolyzable group represented by Q is preferably a substituted or unsubstituted ethynyl group, a halogen atom, an alkoxy group, an alkylcarbonyloxy group, and a substituted or unsubstituted amino group, with a halogen atom being more preferred. When the metal atom represented by M is germanium, the hydrolyzable group represented by Q is preferably a halogen atom, an alkoxy group, an alkylcarbonyloxy group, and a substituted or unsubstituted amino group. When the metal atom represented by M is hafnium, zirconium, or titanium, the hydrolyzable group represented by Q is preferably a halogen atom, an alkoxy group, or an alkylcarbonyloxy group.

[0187] L Ａ Ligands represented by this include monodentate ligands and polydentate ligands.

[0188] Examples of the monodentate ligands mentioned above include hydroxo ligands, nitro ligands, and ammonia.

[0189] Examples of the polydentate ligands mentioned above include hydroxy acid esters, β-diketones, β-ketoesters, malonic acid diesters in which the α-carbon atom may be substituted, hydrocarbons having a π bond, ligands derived from these compounds, and diphosphines.

[0190] Examples of the above-mentioned diphosphines include 1,1-bis(diphenylphosphino)methane, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl, and 1,1'-bis(diphenylphosphino)ferrocene.

[0191] L Ａ As the monovalent organic group represented by the above formula (i), a monovalent organic group having 1 to 20 carbon atoms, as shown in the W group (α) of the above formula (i), can be suitably adopted.

[0192] L Ａ The lower limit of the number of carbon atoms in the monovalent organic group represented by is preferably 2, and more preferably 3. On the other hand, the upper limit of the number of carbon atoms is preferably 10, and more preferably 5. １ The monovalent organic group represented by is preferably a substituted or unsubstituted hydrocarbon group, more preferably a substituted or unsubstituted linear hydrocarbon group or a substituted or unsubstituted aromatic hydrocarbon group, even more preferably a substituted or unsubstituted alkyl group or a substituted or unsubstituted aralkyl group, and particularly preferably an isopropyl group or a benzyl group.

[0193] For a1, 1 and 2 are preferred, with 1 being more preferred.

[0194] b1 is preferably an integer between 2 and 4. By setting b1 to the above value, the proportion of metal atoms in the metal-containing compound (A) can be increased, and the generation of secondary electrons by the metal-containing compound (A) can be promoted more effectively. As a result, the rectangularity of the pattern can be improved.

[0195] As the metal compound precursor (1), a metal halide compound is preferred, and isopropyltin trichloride or benzyltin trichloride is more preferred.

[0196] A method for carrying out a hydrolysis condensation reaction with a metal compound precursor (1) includes, for example, stirring the metal compound precursor (1) in water or a water-containing solvent in the presence of a base such as tetramethylammonium hydroxide, which can be used as needed. In this case, other compounds having hydrolyzable groups may be added as needed. The lower limit of the amount of water used in this hydrolysis condensation reaction is preferably 0.2 moles, more preferably 1 mole, and even more preferably 3 moles, relative to the hydrolyzable groups present in the metal compound precursor (1). By setting the amount of water in the hydrolysis condensation reaction within the above range, a metal-containing compound (A) can be efficiently obtained.

[0197] In the synthesis reaction of the metal-containing compound (A), in addition to the metal compound precursor (1), L in the compound of formula (4) above is also present. Ａ Compounds that can act as polydentate ligands or crosslinking ligands, etc., represented by the formula, may be added. Examples of compounds that can act as crosslinking ligands include compounds having two or more coordinating groups such as hydroxyl groups, isocyanate groups, amino groups, ester groups, and amide groups.

[0198] The lower limit of the temperature for the synthesis reaction of the metal-containing compound (A) is preferably 0°C, more preferably 10°C. The upper limit of the above temperature is preferably 150°C, more preferably 100°C, and even more preferably 50°C.

[0199] The lower limit of the time for the synthesis reaction of the metal-containing compound (A) is preferably 1 minute, more preferably 10 minutes, and even more preferably 1 hour. The upper limit of the above time is preferably 100 hours, more preferably 50 hours, even more preferably 24 hours, and particularly preferably 4 hours.

[0200] (Solvent (F)) An organic solvent is preferred as solvent (F). Specific examples of this organic solvent include, for example, those similar to those exemplified as solvent [B] in the above-mentioned underlayer film-forming composition for metal-containing resist films.

[0201] As the solvent (F), an ether-based solvent is preferred, and propylene glycol monoethyl ether is more preferred.

[0202] (Other optional components) In addition to the metal-containing compound (A) and solvent (F), the metal-containing resist film forming composition may also contain other optional components such as ligands and surfactants.

[0203] (Compounds that can act as ligands) Examples of compounds that can act as ligands include compounds that can act as polydentate ligands or bridging ligands, and specifically include those similar to the compounds that can act as polydentate ligands or bridging ligands exemplified in the synthesis method of metal-containing compound (A).

[0204] (Surfactants) Surfactants are components that improve the applicability, striation, etc. Examples of surfactants include nonionic surfactants such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, and polyethylene glycol distearate, as well as the following trade names: KP341 (Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, and Polyflow No. Examples include 95 (Kyoeisha Chemical Co., Ltd.), F-Top EF301, EF303, EF352 (all from Tochem Products Co., Ltd.), Megafac F171, F173 (both from Dainippon Ink and Chemicals, Inc.), Florard FC430, FC431 (both from Sumitomo 3M Co., Ltd.), Asahiguard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (all from Asahi Glass Co., Ltd.).

[0205] (Method for preparing a composition for forming a metal-containing resist film) A composition for forming a metal-containing resist film can be prepared, for example, by mixing a metal-containing compound (A) and a solvent (F) with other optional components in a predetermined ratio, and preferably by filtering the resulting mixture through a membrane filter with a pore size of 0.4 μm or less. It is preferable that the content of the metal-containing compound (A) in the components other than the solvent (F) in the above metal-containing resist film forming composition is 50% by mass or more. The lower limit of the content of the metal-containing compound (A) is more preferably 60% by mass, and even more preferably 70% by mass. On the other hand, the upper limit of the above content is preferably 100% by mass, but may also be 98% by mass or 95% by mass.

[0206] To explain this resist film formation process in more detail, when the resist film is formed using a metal-containing resist film forming composition, for example, after coating the metal-containing resist film forming composition so that the metal-containing resist film to be formed has a predetermined thickness, the solvent in the coated film is evaporated by pre-baking (hereinafter also referred to as "PB"), thereby forming the metal-containing resist film.

[0207] The PB temperature and PB time can be appropriately determined depending on the type of metal-containing resist film forming composition used. The lower limit of the PB temperature is preferably 30°C, and more preferably 50°C. The upper limit of the PB temperature is preferably 200°C, and more preferably 150°C. The lower limit of the PB time is preferably 10 seconds, and more preferably 30 seconds. The upper limit of the PB time is preferably 600 seconds, and more preferably 300 seconds.

[0208] [Exposure Process] In this process, the resist film is exposed to radiation.

[0209] The radiation used for exposure can be appropriately selected depending on the type of resist film-forming composition used. Examples include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, X-rays, and gamma rays, and particle beams such as electron beams, molecular beams, and ion beams. Among these, electron beams or far ultraviolet light are preferred, and electron beams or KrF excimer laser light (wavelength 248 nm), ArF excimer laser light (wavelength 193 nm), F ２Excimer laser light (wavelength 157 nm), Kr ２ Excimer laser light (wavelength 147 nm), ArKr excimer laser light (wavelength 134 nm), or extreme ultraviolet light (wavelength 13.5 nm, also known as "EUV") is more preferred, and electron beams or EUV are even more preferred. Furthermore, the exposure conditions can be appropriately determined according to the type of resist film-forming composition used, etc.

[0210] Furthermore, in this process, after exposure, post-exposure baking (hereinafter also referred to as "PEB") can be performed to improve the performance of the resist film, such as resolution, pattern profile, and developability. The PEB temperature and PEB time can be appropriately determined according to the type of resist film forming composition used. The lower limit of the PEB temperature is preferably 50°C, and more preferably 70°C. The upper limit of the PEB temperature is preferably 200°C, and more preferably 150°C. The lower limit of the PEB time is preferably 10 seconds, and more preferably 30 seconds. The upper limit of the PEB time is preferably 600 seconds, and more preferably 300 seconds.

[0211] [Development Process] In this process, at least the exposed resist film is developed. At this time, a portion of the underlying resist film may also be developed. Depending on the type of resist film forming composition, development may be by dissolution in a developer solution, by volatilization by heating or reduced pressure, or by etching. This allows a resist pattern to be formed.

[0212] Examples of developers used when employing the above-mentioned developer include alkaline aqueous solutions (alkaline developer) and organic solvent-containing solutions (organic solvent developer).

[0213] The basic solution for alkaline development is not particularly limited, and known basic solutions can be used. Examples of basic solutions for alkaline development include alkaline aqueous solutions in which at least one alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, and 1,5-diazabicyclo-[4.3.0]-5-nonene is dissolved. Among these, aqueous TMAH is preferred, and a 2.38% by mass aqueous TMAH solution is more preferred.

[0214] Examples of organic solvent developers used in organic solvent development include those similar to those exemplified as solvent [B] above. Preferred organic solvents include ester solvents, ether solvents, alcohol solvents, ketone solvents and / or hydrocarbon solvents, with ketone solvents being more preferred, and 2-heptanone being particularly preferred.

[0215] Etching methods include dry etching and wet etching. Dry etching using hydrogen bromide or the like is preferred as the etching method.

[0216] In this process, washing and / or drying may be performed after development as described above. Furthermore, etching may be performed using the resist pattern as a mask. The above-described method can be suitably used as the etching method.

[0217] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0218] [Weight-average molecular weight (Mw), number-average molecular weight (Mn)] The Mw and Mn of the polymers were measured by gel permeation chromatography (detector: differential refractometer) using monodisperse polystyrene as the standard, under analytical conditions of Tosoh Corporation's GPC columns (two "G2000HXL" columns and one "G3000HXL" column), flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, column temperature: 40°C.

[0219] [Average film thickness] The average film thickness was determined by measuring the film thickness at nine arbitrary points at 5 cm intervals, including the center of the resist underlayer film formed on a silicon wafer (substrate), using a spectroscopic ellipsometer (J.A. WOOLLAM's "M2000D"). The average of these film thicknesses was then calculated.

[0220] <Synthesis of [A] polymer and [D2] polymer> [A] polymer having repeating units represented by the following formulas (A-1) to (A-21), and [D2] polymer having repeating units represented by the following formulas (D2-1) to (D2-7), were synthesized according to the procedure described below. In the following formulas, the numbers attached to each repeating unit indicate the content percentage (mol%) of that repeating unit. The composition ratio is as follows: １３ Confirmed via C-NMR.

[0221]

[0222]

[0223]

[0224]

[0225]

[0226]

[0227]

[0228] The following monomers (a-1) to (a-17) (hereinafter also referred to as "[a] compounds") and the following compounds (b-1) to (b-22) (hereinafter also referred to as "[b] compounds") were used in the synthesis of the [A] polymer and the [D2] polymer.

[0229]

[0230]

[0231]

[0232]

[0233] [Synthesis Example 1-1] (Synthesis of Polymer (A-1)) 6.00 g of 4-methyl-2-pentanone was placed in a reaction vessel and maintained at 80°C. A mixture of 4.00 g of compound (a-1), 2.05 g of compound (b-1), 1.35 g of dimethyl-2,2-azobis(2-methylpropionate), and 12.00 g of 4-methyl-2-pentanone was added dropwise from a feeder over 3 hours. The mixture was then stirred at 80°C for 3 hours. The resulting polymerization solution was precipitated and purified with five times the volume of heptane to obtain polymer (A-1) as a white solid. The Mw and Mn of the obtained [A] polymer or [D2] polymer are shown in Table 1. In the table, "-" indicates that the corresponding component was not used. The same applies to subsequent tables.

[0234] [Synthesis Examples 1-2 to 1-9 and 1-14 to 1-21] (Synthesis of polymers (A-2) to (A-9) and polymers (A-14) to (A-21)) Polymers (A-2) to (A-9) and polymers (A-14) to (A-21) were synthesized in the same manner as polymer (A-1), except that compound (a-1) and compound (b-1) were of the types and amounts of compound [a] and compound [b] shown in Table 1.

[0235] [Synthesis Example 1-10] (Synthesis of Polymer (A-10)) In a reaction vessel, 10.80 g of (a-16), 3.00 g of (b-9), and 87.30 g of methyl isobutyl ketone were charged under a nitrogen atmosphere and dissolved. 1.00 g of p-toluenesulfonic acid monohydrate was added to the reaction vessel, and the mixture was heated to 85°C and reacted for 4 hours. After the reaction was complete, the reaction solution was transferred to a separatory funnel, and the organic phase was washed with 200 g of methyl isobutyl ketone and 400 g of water. After separating the aqueous phase, the obtained organic phase was concentrated in an evaporator, and the residue was added dropwise to 500 g of methanol to obtain a precipitate. The precipitate was collected by suction filtration and washed several times with 100 g of methanol. Then, polymer (A-10) was obtained by drying in a vacuum dryer at 60°C for 12 hours.

[0236] [Synthesis Example 1-12] (Synthesis of polymer (A-12)) Polymer (A-12) was obtained in the same manner as in Synthesis Example 1-10, except that 10.80 g of (a-16) was changed to 16.00 g of (a-9).

[0237] [Synthesis Example 1-11] (Synthesis of Polymer (A-11)) In a reaction vessel, under a nitrogen atmosphere, 6.00 g of the above polymer (A-10), 5.83 g of (b-10), 90 g of methyl isobutyl ketone, and 45.0 g of methanol were added and stirred. Then, 85.5 g of 25% by mass aqueous solution of tetramethylammonium hydroxide was added and the mixture was reacted at 50°C for 6 hours. After cooling the reaction solution to 30°C, 200.0 g of 5% by mass aqueous solution of oxalic acid was added. After removing the aqueous phase, the obtained organic phase was concentrated in an evaporator, and the residue was added dropwise to 500 g of methanol to obtain a precipitate. The precipitate was recovered by suction filtration and washed several times with 100 g of methanol. Then, polymer (A-11) was obtained by drying in a vacuum dryer at 60°C for 12 hours.

[0238] [Synthesis Example 1-13] (Synthesis of polymer (A-13)) Polymer (A-13) was obtained in the same manner as in Synthesis Example 1-11, except that 6.00 g of (A-10) was changed to 7.71 g of (A-12).

[0239] [Synthesis Examples 2-1 to 2-7] (Synthesis of polymers (D2-1) to (D2-7)) Polymers (D2-1) to (D2-7) were synthesized in the same manner as polymer (A-1), except that compound (a-1) and compound (b-1) were of the types and amounts of compound [a] and compound [b] shown in Table 1.

[0240]

[0241] <Preparation of Underlayer Forming Composition for Resist Films> The polymers, solvents, acid generators, compounds, polymers, additives, and crosslinking agents used in the preparation of the underlayer forming composition for resist films (hereinafter also referred to as "the composition") are shown below.

[0242] [A Polymer] A-1 to A-21: The polymers synthesized above (A-1) to (A-21)

[0243] [B Solvent] B-1: Propylene glycol monomethyl ether acetate B-2: Propylene glycol monomethyl ether B-3: Methyl 2-hydroxyisobutyrate

[0244] [C] Acid Generators: C-1 to C-10: Compounds represented by the following formulas (C-1) to (C-10)

[0245]

[0246]

[0247]

[0248] [D1] Compounds D-1 to D-17: Compounds represented by the following formulas (D1-1) to (D1-17)

[0249]

[0250]

[0251] [D2] Polymers D2-1 to D2-7: The polymers synthesized above (D2-1) to (D2-7)

[0252] [E] Additives E-1: Compound represented by the following formula (E-1) E-2: Compound represented by the following formula (E-2) E-3: Compound represented by the following formula (E-3) E-4: Compound represented by the following formula (E-4) E-5: Compound represented by the following formula (E-5)

[0253]

[0254] [F Additive] F-1: Compound represented by the following formula (F-1)

[0255]

[0256] [Example 1-1] [A] 100 parts by mass of (A-1) as a polymer and [D1] 2 parts by mass of (D1-1) as a compound were dissolved in [B] 2,000 parts by mass of (B-1) and 18,000 parts by mass of (B-2) as solvents. The resulting solution was filtered through a polytetrafluoroethylene (PTFE) membrane filter with a pore size of 0.45 μm to prepare composition (J-1).

[0257] [Examples 1-2 to 1-34 and Comparative Example 1-1] Compositions (J-2) to (J-34) and (CJ-1) were prepared in the same manner as in Example 1-1, except that the components used were of the types and in the amounts shown in Table 2 below.

[0258]

[0259] <Evaluation> Using the compositions prepared above, the rectangularity of the resist pattern obtained by EUV exposure using the resist film formation composition was evaluated by the following method. The evaluation results are shown in Table 3 below.

[0260] <Preparation of Resist Composition (R-1)> Compound (S-1) used in the preparation of resist composition (R-1) was synthesized by the following procedure. In a reaction vessel, 6.5 parts by mass of isopropyltin trichloride was added while stirring 150 mL of 0.5 N aqueous sodium hydroxide solution, and the mixture was stirred for 2 hours. The precipitated material was filtered off, washed twice with 50 parts by mass of water, and then dried to obtain compound (S-1). Compound (S-1) is the oxidized hydroxide product (i-PrSnO) of the hydrolysis product of isopropyltin trichloride. （３／２-ｘ／２） (OH) ｘ(The structural units were defined as 0 < x < 3).

[0261] Two parts by mass of the synthesized compound (S-1) were mixed with 98 parts by mass of propylene glycol monoethyl ether. The resulting mixture was then filtered to remove residual water using an activated 4 Å molecular sieve, and then filtered through a 0.2 μm pore size filter to prepare the resist composition (R-1).

[0262] [Rectangular Resist Pattern (EUV Exposure, Wet Development)] An organic underlayer film formation material (HM8006 from JSR Corporation) was applied to a 12-inch silicon wafer by a rotary coating method using a spin coater (CLEAN TRACK ACT12 from Tokyo Electron Limited), and then heated at 250°C for 60 seconds to form an organic underlayer film with an average thickness of 100 nm. The resist underlayer film formation composition prepared above was applied to this organic underlayer film, heated at 220°C for 60 seconds, and then cooled at 23°C for 30 seconds to form a resist underlayer film with an average thickness of 5 nm. The resist composition (R-1) was applied to this resist underlayer film by a rotary coating method using the spin coater, and after a predetermined time had elapsed, heated at 90°C for 60 seconds and then cooled at 23°C for 30 seconds to form a resist film with an average thickness of 35 nm. The resist film was exposed using an EUV scanner (ASML's "TWINSCAN NXE:3300B" (NA 0.3, sigma 0.9, quadruple pole illumination, wafer-mounted 1:1 line-and-space mask with a line width of 16 nm)). After exposure, the substrate was heated at 110°C for 60 seconds, then cooled at 23°C for 60 seconds. Subsequently, it was developed using the paddle method with 2-heptanone (20-25°C) and dried to obtain an evaluation substrate with a resist pattern formed on it. A scanning electron microscope (Hitachi High-Tech Corporation's "CG-6300") was used to measure and observe the resist pattern on the evaluation substrate. The rectangularity of the resist pattern was evaluated as "A" (good) if the cross-sectional shape of the pattern was rectangular, and "B" (poor) if there was a hem in the cross-section of the pattern.

[0263] [Resist Pattern Peeling (EUV Exposure)] The resist pattern was measured and observed in the same manner as for the evaluation of the resist pattern rectangularity. Resist pattern peeling was evaluated as "A" (good) if no peeling occurred, and "B" (poor) if peeling occurred.

[0264]

[0265] [Rectangular Resist Pattern (EUV Exposure, Dry Development)] An organic underlayer film formation material (HM8006 from JSR Corporation) was applied to a 12-inch silicon wafer by a rotary coating method using a spin coater (CLEAN TRACK ACT12 from Tokyo Electron Limited), and then heated at 250°C for 60 seconds to form an organic underlayer film with an average thickness of 100 nm. The resist underlayer film formation composition prepared above was applied to this organic underlayer film, heated at 220°C for 60 seconds, and then cooled at 23°C for 30 seconds to form a resist underlayer film with an average thickness of 5 nm. The resist composition (R-1) was applied to this resist underlayer film by a rotary coating method using the spin coater, and after a predetermined time had elapsed, heated at 90°C for 60 seconds and then cooled at 23°C for 30 seconds to form a resist film with an average thickness of 35 nm. The resist film was exposed using an EUV scanner (ASML's "TWINSCAN NXE:3300B" (NA 0.3, sigma 0.9, quadruple pole illumination, wafer-mounted 1:1 line-and-space mask with a line width of 16 nm)). After exposure, the substrate was heated at 110°C for 60 seconds, then cooled at 23°C for 60 seconds. Subsequently, an evaluation substrate with a resist pattern was obtained by developing it with hydrogen bromide. A scanning electron microscope (Hitachi High-Tech Corporation's "CG-6300") was used to measure and observe the resist pattern on the evaluation substrate. The rectangularity of the resist pattern was evaluated as "A" (good) if the cross-sectional shape of the pattern was rectangular, and "B" (poor) if there was a drooping edge in the cross-section of the pattern.

[0266] [Resist Pattern Peeling (EUV Exposure)] The resist pattern was measured and observed in the same manner as for the evaluation of the resist pattern rectangularity. Resist pattern peeling was evaluated as "A" (good) if no peeling occurred, and "B" (poor) if peeling occurred.

[0267]

[0268] As can be seen from the results in Tables 3 and 4, the resist underlayer film formed from the composition of the example showed superior resistance pattern rectangularity and resistance pattern peeling suppression compared to the resist underlayer film formed from the composition of the comparative example.

[0269] The resist underlayer film formation composition of the present invention makes it possible to form a film with excellent resist pattern rectangularity and pattern peeling suppression. The semiconductor substrate manufacturing method of the present invention uses a resist underlayer film formation composition capable of forming a resist underlayer film with excellent resist pattern rectangularity and pattern peeling suppression, thus enabling efficient manufacturing of semiconductor substrates. Therefore, these can be suitably used in the manufacture of semiconductor devices and the like.

Claims

1. A composition for forming a resist underlayer film containing a polymer and a solvent, wherein at least: the composition for forming a resist underlayer film further contains a compound having a partial structure represented by the following formula (i), or the polymer contains a partial structure represented by the following formula (i); and the polymer has at least one monovalent group (X) selected from the group consisting of a group having a phenolic hydroxyl group, a group represented by the following formula (2-1), a group represented by the following formula (2-2), a group represented by the following formula (2-3), a group represented by the following formula (2-4), a group represented by the following formula (2-5), a group represented by the following formula (2-6), a group represented by the following formula (2-7), and a group represented by the following formula (2-8), the composition for forming a resist underlayer film. (In the above formula (i), X - is -COO - or -SO ３ - ; W is a 1+p-valent organic group having 1 to 40 carbon atoms, provided that when X - is -SO ３ - , a group other than a fluorine atom or a hydrogen atom is bonded to the carbon atom at the α-position to the sulfur atom of -SO ３ - in W; Z ＋ is a q-valent organic cation; * is a bonding hand to another partial structure in the polymer or the compound; and p and q are each independently 0 or 1, provided that p+q is 1 when * is a bonding hand to another partial structure in the polymer.) (In the above formulas (2-1) to (2-8), R ７ is each independently a divalent organic group having 1 to 20 carbon atoms or a single bond; R ８ , R ９ , R １０ and R １３ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms; Cy is a cyclic structure having 3 to 20 ring members formed together with the two carbon atoms in formula (2-2); R １１ is a hydrogen atom, a monovalent organic group having 1 to 20 carbon atoms or a single bond; R １２ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. ** is a bond with an atom constituting Cy. However, R １１ If it is a single bond, R １１ It bonds with **. * represents the bonding site with each atom that makes up the polymer.

2. The resist underlayer film forming composition according to claim 1, wherein the polymer has at least one monovalent group (X) selected from the group consisting of a group represented by formula (2-1), a group represented by formula (2-2), a group represented by formula (2-3), a group represented by formula (2-4), a group represented by formula (2-5), a group represented by formula (2-6), a group represented by formula (2-7), and a group represented by formula (2-8).

3. The resist underlayer film forming composition according to claim 1, wherein the compound is a compound represented by the following formula (A). (In the above formula (A), X - This is equivalent to equation (i) above. W Ａ X is a monovalent organic group having 1 to 40 carbon atoms. - ga-SO ３ - If W Ａ -SO ３ - A group other than a fluorine atom or a hydrogen atom is bonded to the α-carbon of the sulfur atom. Ａ ＋ (This is an organic cation.) 4. The resist underlayer film forming composition according to claim 1, wherein the polymer has repeating units derived from a compound represented by the following formula (B1), repeating units derived from a compound represented by the following formula (B2), repeating units derived from a compound represented by the following formula (B3), or repeating units derived from a compound represented by the following formula (B4). (In the above formulas (B1) to (B4), X - This is equivalent to equation (i) above. R Ｂ Each of these is independently a hydrogen atom, a halogen atom, or a monovalent organic group having 1 to 20 carbon atoms. Ｂ Each of these is independently a single bond or a divalent linking group. Ｂ１ Each of these is independently a divalent organic group having 1 to 40 carbon atoms. However, X - ga-SO ３ - If W Ｂ１ -SO ３ - A group other than a fluorine atom or a hydrogen atom is bonded to the α-carbon of the sulfur atom. １ and L ２ Each of these is independently a single bond or a divalent linking group. Each of these is independently an aromatic ring. Z Ｂ１ ＋ These are, independently, organic cations. Ｂ２ X is a monovalent organic group having 1 to 40 carbon atoms. - ga-SO ３ - If W Ｂ２ -SO ３ - A group other than a fluorine atom or a hydrogen atom is bonded to the α-carbon of the sulfur atom. Ｂ２ ＋ These are, independently, monovalent organic cations.

5. A composition for forming an underlayer of a resist film that is subjected to exposure with extreme ultraviolet light, as described in any one of claims 1 to 4.

6. The resist underlayer film forming composition according to any one of claims 1 to 4, wherein the resist film contains a metal.

7. The resist film is formed by a metal-containing resist film forming composition, the metal-containing resist film forming composition contains a metal-containing compound and a solvent, and the proportion of the metal-containing compound in the metal-containing resist film forming composition other than the solvent is 50% by mass or more, according to claim 6.

8. The resist underlayer film forming composition according to any one of claims 1 to 4, wherein the thickness of the resist underlayer film is 5 nm or less.

9. A method for manufacturing a semiconductor substrate, comprising: a step of directly or indirectly applying a composition for forming a resist underlayer film onto a substrate; a step of forming a resist film on the resist underlayer film formed by the step of applying the composition for forming a resist underlayer film; a step of exposing the resist film to radiation; and a step of developing at least the exposed resist film, wherein the composition for forming a resist underlayer film contains a polymer and a solvent, and at least: the composition for forming a resist underlayer film further contains a compound having a partial structure represented by the following formula (i), or the polymer contains a partial structure represented by the following formula (i), and the polymer has at least one monovalent group (X) selected from the group consisting of a group having a phenolic hydroxyl group, a group represented by the following formula (2-1), a group represented by the following formula (2-2), a group represented by the following formula (2-3), a group represented by the following formula (2-4), a group represented by the following formula (2-5), a group represented by the following formula (2-6), a group represented by the following formula (2-7), and a group represented by the following formula (2-8). (In the above formula (i), X - is -COO - or -SO ３ - . W is a (1+p)-valent organic group having 1 to 40 carbon atoms, provided that when X - is -SO ３ - , a group other than a fluorine atom or a hydrogen atom is bonded to the carbon atom at the α-position to the sulfur atom of -SO ３ - in W. Z ＋ is a q-valent organic cation. * represents a bond to another partial structure in the polymer or the compound. p and q are each independently 0 or 1, provided that when * is a bond to another partial structure in the polymer, p+q is 1.) (In the above formulas (2-1) to (2-8), R ７ are each independently a divalent organic group having 1 to 20 carbon atoms or a single bond. R ８ , R ９ , R １０ and R １３ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. Cy is a ring structure with 3 to 20 members, formed together with the two carbon atoms in formula (2-2). １１ R is a hydrogen atom, a monovalent organic group having 1 to 20 carbon atoms, or a single bond. １２ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. ** is a bond with an atom constituting Cy. However, R １１ If it is a single bond, R １１ It bonds with **. * represents the bonding site with each atom that makes up the polymer.

10. The method for manufacturing a semiconductor substrate according to claim 9, wherein the polymer has at least one monovalent group (X) selected from the group consisting of a group represented by formula (2-1), a group represented by formula (2-2), a group represented by formula (2-3), a group represented by formula (2-4), a group represented by formula (2-5), a group represented by formula (2-6), a group represented by formula (2-7), and a group represented by formula (2-8).

11. The method for manufacturing a semiconductor substrate according to claim 9, wherein the resist film is formed using a metal-containing resist film forming composition, the metal-containing resist film forming composition contains a metal-containing compound and a solvent, and the proportion of the metal-containing compound in the metal-containing resist film forming composition other than the solvent is 50% by mass or more.

12. A method for manufacturing a semiconductor substrate according to any one of claims 9 to 11, wherein the radiation is extreme ultraviolet light.

13. A method for manufacturing a semiconductor substrate according to any one of claims 9 to 11, wherein the thickness of the resist underlayer film is 5 nm or less.

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