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

Abstract

Provided are a composition for forming a resist underlayer film and a method for manufacturing a semiconductor substrate, the composition being capable of forming a film having excellent embedding property and bending resistance. The composition for forming a resist underlayer film contains a carbonyl group-containing compound and a solvent. The carbonyl group-containing compound has a molecular weight of 210 or more and has a partial structure represented by formula (A1). (In the formula: Ar1 and Ar2 are each an aromatic ring having 6 to 20 carbon atoms; R1 and R2 are each a hydroxy group, a nitro group, an amino group, a sulfanyl group, a halogen atom, or a monovalent organic group having 1 to 20 carbon atoms, or when a plurality of R1 groups or R2 groups are present, two R1 groups or R2 groups among the plurality of R1 groups or R2 groups are combined with each other to form a ring structure having 3 to 20 carbon atoms; and * and ** are each a binding site for other atoms constituting the carbonyl group-containing compound.)

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 the manufacturing of semiconductor devices, for example, a multilayer resist process is used to form a resist pattern 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.

[0003] Various studies have been conducted on materials used in such resist underlayer formation compositions (International Publication No. 2011 / 108365).

[0004] International Publication No. 2011 / 108365

[0005] Recently, substrates with patterns such as trenches and holes have been increasingly used, and resist underlayer compositions are required to have sufficient embedding properties to be embedded in the substrate patterns and to have bending resistance regardless of whether or not there are patterns.

[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 film with excellent embedding properties and bending resistance.

[0007] In one embodiment, the present invention relates to a composition for forming a resist underlayer film, comprising a carbonyl group-containing compound (hereinafter also referred to as "[A] compound") and a solvent (hereinafter also referred to as "[B] solvent), wherein the carbonyl group-containing compound has a molecular weight of 210 or more and has a substructure represented by the following formula (A1). (In the above formula (A1), Ar １ and Ar ２each independently represents an aromatic ring having 6 to 20 carbon atoms. p is an integer of 0 to 4. q is an integer of 0 to 4. When p is 2 or more, a plurality of R １ are the same or different. When q is 2 or more, a plurality of R ２ are the same or different. R １ is a hydroxy group, a nitro group, an amino group, a sulfanyl group, a halogen atom or a monovalent organic group having 1 to 20 carbon atoms, or R １ when a plurality of R １ exist, two of them are bonded to each other together with two carbon atoms of Ar １ to which they are bonded to form a ring structure having 3 to 20 carbon atoms. R ２ is a hydroxy group, a nitro group, an amino group, a sulfanyl group, a halogen atom or a monovalent organic group having 1 to 20 carbon atoms, or R ２ when a plurality of R ２ exist, two of them are bonded to each other together with two carbon atoms of Ar ２ to which they are bonded to form a ring structure having 3 to 20 carbon atoms. * is a bonding site to another atom constituting the carbonyl group-containing compound. ** is a bonding site to another atom constituting the carbonyl group-containing compound. n is an integer of 0 to 4. m is an integer of 0 to 4.)

[0008] According to the resist underlayer film-forming composition, a resist underlayer film excellent in embedding property and bending resistance can be formed. Although the reason for this is not clear, it is presumed as follows. The compound [A] has an aromatic ring and a carbonyl group having high electron density and affinity for solvents, substrates, etc., and a film formed by the resist underlayer film-forming composition can exhibit rigidity, high elasticity and film quality modifying properties. As a result, it is presumed that the resist underlayer film-forming composition can form a resist underlayer film excellent in embedding property and bending resistance.

[0009] In other embodiments, the present invention relates to a method for manufacturing a semiconductor substrate, comprising the steps of: coating a resist underlayer film forming composition directly or indirectly onto a substrate; directly or indirectly forming a resist pattern on the resist underlayer film formed by the coating step; and etching using the resist pattern as a mask, wherein the resist underlayer film forming composition contains a carbonyl group-containing compound and a solvent, and the carbonyl group-containing compound has a molecular weight of 210 or more and has a substructure represented by the following formula (A1). (In the above formula (A1), Ar １ and Ar ２ Each of these is an independent aromatic ring with 6 to 20 carbon atoms. p is an integer from 0 to 4. q is an integer from 0 to 4. If p is 2 or greater, multiple R １ They are the same or different. If q is 2 or more, there are multiple R ２ They are either the same or different. １ is a hydroxyl group, nitro group, amino group, sulfanyl group, halogen atom, or monovalent organic group having 1 to 20 carbon atoms, or R １ If multiple R １ Two of them can be combined and joined together as Ar １ It forms a ring structure with 3 to 20 carbon atoms together with the two carbon atoms. ２ is a hydroxyl group, nitro group, amino group, sulfanyl group, halogen atom, or monovalent organic group having 1 to 20 carbon atoms, or R ２ If multiple R ２ Two of them can be combined and joined together as Ar ２ It forms a ring structure with 3 to 20 carbon atoms together with the two carbon atoms. * indicates a bonding site with other atoms constituting the carbonyl group-containing compound. ** indicates a bonding site with other atoms constituting the carbonyl group-containing compound. n is an integer from 0 to 4. m is an integer from 0 to 4.

[0010] The resist underlayer film formation composition in the semiconductor substrate manufacturing method contains a compound [A] capable of forming a film with rigidity, high elasticity, and film quality homogeneity. Therefore, a resist underlayer film with excellent embedding and bending resistance can be formed, thereby enabling the efficient manufacture of semiconductor substrates with good pattern shapes.

[0011] In this specification, "fused ring" refers to a polycyclic structure formed by two adjacent rings sharing one edge (two adjacent atoms). "Ring assembly" refers to a structure in which two rings are joined by a single bond. "Spiro ring" refers to a polycyclic structure formed by two adjacent rings sharing one atom. "Organic group" refers to a group containing at least one carbon atom. Organic groups include cyano groups, carboxyl groups, formyl groups, etc.

[0012] The resist underlayer film formation composition allows for the formation of a film with excellent embedding properties and bending resistance. The semiconductor substrate manufacturing method allows for the formation of a resist underlayer film with excellent embedding properties and bending resistance, thereby obtaining a semiconductor substrate with a good pattern shape. Therefore, these can be suitably used in the manufacture of semiconductor devices, where further miniaturization is expected in the future.

[0013] This is a schematic plan view illustrating the method for evaluating bending resistance.

[0014] 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 preferable.

[0015] Composition for forming a resist underlayer film The resist underlayer film formation composition contains compound [A] and solvent [B]. The resist underlayer film formation composition may contain optional components as long as they do not impair the effects of the present invention.

[0016] The following describes each component contained in the resist underlayer film forming composition.

[0017] <[A] Compound> The [A] compound has a molecular weight of 210 or more and has a substructure represented by the following formula (A1). The resist underlayer film forming composition may contain one or more [A] compounds. (In the above formula (A1), Ar １ and Ar ２ Each of these is an independent aromatic ring with 6 to 20 carbon atoms. p is an integer from 0 to 4. q is an integer from 0 to 4. If p is 2 or greater, multiple R １ They are the same or different. If q is 2 or more, there are multiple R ２ They are either the same or different. １ is a hydroxyl group, nitro group, amino group, sulfanyl group, halogen atom, or monovalent organic group having 1 to 20 carbon atoms, or R １ If multiple R １ Two of them can be combined and joined together as Ar １ It forms a ring structure with 3 to 20 carbon atoms together with the two carbon atoms. ２ is a hydroxyl group, nitro group, amino group, sulfanyl group, halogen atom, or monovalent organic group having 1 to 20 carbon atoms, or R ２ If multiple R ２ Two of them can be combined and joined together as Ar ２ It forms a ring structure with 3 to 20 carbon atoms together with the two carbon atoms. * indicates a bonding site with other atoms constituting the carbonyl group-containing compound. ** indicates a bonding site with other atoms constituting the carbonyl group-containing compound. n is an integer from 0 to 4. m is an integer from 0 to 4.

[0018] In the above formula (A1), Ar １ and Ar ２Examples of aromatic rings having 6 to 20 carbon atoms represented by Ar include aromatic hydrocarbon rings having 6 to 20 carbon atoms such as benzene rings, naphthalene rings, anthracene rings, phenalene rings, phenanthrene rings, pyrene rings, fluorene rings, perylene rings, and biphenyl rings; aromatic heterocycles having 6 to 20 carbon atoms such as indole rings, benzimidazole rings, benzofuran rings, quinoline rings, carbazole rings, and dibenzofuran rings; or combinations thereof. These combinations of rings may be fused ring structures, ring aggregate structures, or spiro ring structures. １ and Ar ２ The aromatic rings are preferably at least one aromatic hydrocarbon ring selected independently from the group consisting of a benzene ring, a naphthalene ring, anthracene ring, a phenalene ring, a phenanthrene ring, a pyrene ring, and a fluorene ring, and more preferably a benzene ring, a naphthalene ring, a pyrene ring, or a fluorene ring. Among these, the above Ar １ and Ar ２ The aromatic rings are preferably, independently, benzene rings or naphthalene rings, and more preferably benzene rings.

[0019] p and q are preferably independent integers between 0 and 3, and more preferably integers between 0 and 2. p + q is preferably 1 or greater. p or q is preferably 0.

[0020] R １ and R ２ Examples of halogen atoms represented by this formula include fluorine, chlorine, bromine, and iodine.

[0021] R １ and R ２ Examples of monovalent organic groups having 1 to 20 carbon atoms represented by include monovalent hydrocarbon groups having 1 to 20 carbon atoms, groups having a divalent heteroatom-containing linking group between carbon atoms of the hydrocarbon group or at the terminal end of the hydrocarbon group (hereinafter also referred to as "group (α)"), groups in which some or all of the hydrogen atoms of the hydrocarbon group or group (α) are replaced with monovalent heteroatom-containing substituents, or groups that combine these.

[0022] Examples of monovalent hydrocarbon groups having 1 to 20 carbon atoms include monovalent linear hydrocarbon groups having 1 to 20 carbon atoms, monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms, or groups combining these.

[0023] Examples of monovalent chain hydrocarbon groups having 1 to 20 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.

[0024] Examples of monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms include cycloalkyl groups such as cyclopentyl and cyclohexyl groups; cycloalkenyl groups such as cyclopropenyl, cyclopentenyl, and cyclohexenyl groups; bridged ring saturated hydrocarbon groups such as norbornyl, adamantyl, and tricyclodecyl groups; and bridged ring unsaturated hydrocarbon groups such as norbornyl and tricyclodecenyl groups.

[0025] Examples of monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms include aryl groups such as phenyl, tolyl, xyl, naphthyl, anthracenyl, pyrenyl, and fluorenyl groups; and aralkyl groups such as benzyl and phenethyl groups.

[0026] Examples of heteroatoms that constitute a divalent heteroatom-containing linking group or a monovalent heteroatom-containing substituent include oxygen, nitrogen, sulfur, phosphorus, silicon, and halogen atoms. The halogen atoms are as described above.

[0027] Examples of divalent heteroatom-containing linking groups include -CO-, -CS-, -NR'-, -O-, -S-, -SO-, and -SO ２ -Or groups that combine these. R' is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms.

[0028] Examples of monovalent heteroatom-containing substituents include hydroxyl groups, sulfanyl groups, cyano groups, nitro groups, amino groups, and halogen atoms.

[0029] R １ or R ２ If there are multiple R's, then two R's １ or two R ２ Ar is formed when these are combined with each other and these are joined together. １ or Ar ２ The ring structure having 3 to 20 carbon atoms formed with the two carbon atoms includes, for example, the structure corresponding to the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, the aromatic ring having 6 to 20 carbon atoms, and one or more methanediyl groups (-CH) in the structure corresponding to the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. ２ Examples include aliphatic heterocyclic structures in which -) is replaced with the above-mentioned divalent heteroatom-containing linking group, or structures combining these. These ring combinations may be fused ring structures, ring aggregate structures, or spiro ring structures. In the above-mentioned aliphatic heterocyclic structures, -CO-, -NR'-, or -O- are preferred as the above-mentioned divalent heteroatom-containing linking group. R' is as described above.

[0030] R １ and R ２ Preferably, each of these groups independently is an aryl group having 6 to 20 carbon atoms, an alkylaryl group having 7 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, an alkylarylamino group having 7 to 20 carbon atoms, an acylamino group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms, a hydroxyl group, or a combination thereof. Preferably, each group is an aryl group having 6 to 10 carbon atoms, an alkylaryl group having 7 to 10 carbon atoms, an arylamino group having 6 to 10 carbon atoms, or an alkylaryl group having 7 to 10 carbon atoms. More preferably are iliamino groups, acylamino groups having 2 to 10 carbon atoms, alkoxy groups having 1 to 10 carbon atoms, monovalent fluorinated chain hydrocarbon groups having 1 to 10 carbon atoms, hydroxyl groups, or combinations thereof. Even more preferably are phenyl groups, naphthyl groups, methylphenyl groups, ethylphenyl groups, phenylamino groups, methylphenylamino groups, benzoylamino groups, acetylamino groups, methoxy groups, ethoxy groups, trifluoromethyl groups, 2,2,2-trifluoroethyl groups, hydroxyl groups, or combinations thereof.

[0031] R１ or R ２ If there are multiple R's, then two R's １ or two R ２ The ring structure formed by the combination of these elements is preferably an aromatic ring having 6 to 20 carbon atoms, an aliphatic heterocyclic structure, or a structure combining these. More preferably, the structure is one in which one or more methanediyl groups of an aromatic hydrocarbon ring having 6 to 10 carbon atoms or a cycloalkane having 5 to 8 carbon atoms are substituted with -CO-, -NH-, or -O-, respectively, or a structure combining these. A condensed ring structure of a benzene ring and piperidine-4-one, a condensed ring structure of a benzene ring and piperazine, or a condensed ring structure of a benzene ring and 1,4-dioxane is even more preferred.

[0032] n and m are preferably independent integers between 0 and 3, and more preferably integers between 0 and 2.

[0033] [A] The compound is preferably a compound represented by the following formula (A1-1), a compound represented by the following formula (A1-2), a compound represented by the following formula (A1-3), a compound represented by the following formula (A1-4), a polymer having a repeating unit represented by the following formula (A1-5), or a polymer having a repeating unit represented by the following formula (A1-6). (In the above formulas (A1-1) to (A1-6), Ar １ Ar ２ , R １ , R ２ , p and q are equivalent to those in the above formula (A1). Ar １ Ar ２ , R １ , R ２ If there are multiple instances of p, q, X, and Y, then there are multiple Ar １ Ar ２ , R １ , R ２ p, q, X, and Y are either identical or different from each other. １ is a u-valent organic group having 1 to 40 carbon atoms. u is an integer from 1 to 4. X and Y are independently a single bond, an oxygen atom, -NH-, -CO-, or a divalent organic group. s is independently 1 or 2. W ２This is a divalent organic group having 1 to 40 carbon atoms. ３ (L is a divalent organic group with 1 to 40 carbon atoms. L is a single bond or a divalent organic group with 1 to 10 carbon atoms.)

[0034] In the above formula (A1-2), W １ As an organic group with 1 to 40 carbon atoms represented by the above formula (A1), R １ A group obtained by removing u hydrogen atoms from structure (a), which corresponds to a group that extends the monovalent organic group having 1 to 20 carbon atoms to 40 carbon atoms as shown in [reference], can be suitably adopted. １ The above structure (a) is preferably a structure containing an aromatic ring or imide ring having 6 to 20 carbon atoms, or a structure combining these, more preferably a structure containing an aromatic hydrocarbon ring or aromatic imide ring having 6 to 14 carbon atoms, or a structure combining these, and even more preferably a benzene ring, naphthalene ring, anthracene ring, pyrene ring, fluorene ring, biphenyl ring, phthalimide structure, benzoisoquinoline-1,3-dione structure, pyromellitic acid diimide structure, or a structure combining these. １ If it contains an imide ring-containing structure, the nitrogen atom in the imide ring-containing structure and Ar of the above formula (A1-2) １ It is preferable that the carbon atoms are bonded to each other.

[0035] If the above structure (a) has substituents, examples of substituents include halogen atoms such as fluorine, chlorine, bromine, and iodine atoms; hydroxyl groups; carboxyl groups; cyano groups; nitro groups; amino groups; alkyl groups, alkoxy groups, alkoxycarbonyl groups, alkoxycarbonyloxy groups, acyl groups, acyloxy groups, ethenyl groups (vinyl groups), ethynyl groups, or groups in which the hydrogen atoms of these groups are substituted with halogen atoms; oxo groups (=O); or combinations thereof.

[0036] u is preferably an integer between 1 and 3, and more preferably 1 or 2.

[0037] In the above formulas (A1-3) and (A1-4), the divalent organic groups represented by X and Y are R in the above formula (A1). １A group obtained by removing one hydrogen atom from a monovalent organic group having 1 to 20 carbon atoms (excluding monovalent characteristic groups or functional groups such as cyano groups, carboxyl groups, and formyl groups) shown in [reference] can be suitably adopted. As the divalent organic group in X and Y, a divalent hydrocarbon group or a group combining the divalent hydrocarbon group with the divalent heteroatom-containing linking group is preferred. Examples of the divalent hydrocarbon group include alkanediyl groups, arenediyl groups, or groups combining these. As the alkanediyl group, alkanediyl groups having 1 to 8 carbon atoms, such as methanediyl group, ethanediyl group, 1,3-propanediyl group, 2,2-propanediyl group, and isopentane-1,2-diyl, are preferred. As the arenediyl group, arenediyl groups having 6 to 10 prime numbers, such as benzenediyl group and naphthalenediyl group, are preferred. The divalent heteroatom-containing linking groups in X and Y are preferably -CO-, -NH-, -O-, or combinations thereof. X and Y are each preferably independently a single bond, an oxygen atom, or -NH-.

[0038] In the above formula (A1-5), W ２ As a divalent organic group having 1 to 40 carbon atoms represented by the above formula (A1-2), W １ A group obtained by removing two hydrogen atoms from the above structure (a) shown in can be suitably adopted. In particular, W ２ In the above structure (a), an aromatic ring having 6 to 40 carbon atoms is preferred. As such an aromatic ring, Ar of formula (A1) １ A ring with 6 to 20 carbon atoms, represented by the above, can be suitably used, with the number of carbon atoms extended up to 40. ２ Preferably, the ring is at least one aromatic hydrocarbon ring selected from the group consisting of a benzene ring, a naphthalene ring, anthracene ring, a phenalene ring, a phenanthrene ring, a pyrene ring, and a fluorene ring, and more preferably a benzene ring, a naphthalene ring, a pyrene ring, a fluorene ring, or a combination thereof.

[0039] W ２ If the above structure (a) has substituents, the substituents are W １A substituent that can be included in the above structure (a) can be suitably employed. A hydroxy group is preferable as the substituent.

[0040] In the above formula (A1-5), as the divalent organic group having 1 to 10 carbon atoms represented by L, the divalent organic groups represented by X and Y in the above formula (A1-3) and formula (A1-4) can be suitably employed. L is preferably a single bond.

[0041] In the above formula (A1-6), W ３ as the divalent organic group having 1 to 40 carbon atoms represented by W in the above formula (A1-2), １ a group obtained by removing two hydrogen atoms from the above structure (a) shown can be suitably employed. W ３ preferred examples of the above structure (a) include at least one structure (i) selected from the group consisting of the aromatic ring having 6 to 20 carbon atoms, the chain hydrocarbon structure and the imide ring-containing structure, or a structure obtained by combining the structure (i) with the above divalent heteroatom-containing linking group. As the above chain hydrocarbon structure, a structure corresponding to the monovalent chain hydrocarbon group having 1 to 20 carbon atoms shown for R in the above formula (A1) １ can be suitably employed. Among these, as the above structure (a) for W ３ more preferred is at least one structure (i-1) selected from the group consisting of an aromatic hydrocarbon ring having 6 to 14 carbon atoms, a chain saturated hydrocarbon structure having 1 to 10 carbon atoms, and an aromatic imide ring-containing structure, or a structure obtained by combining the structure (i-1) with -CO-, -NH-, -O- or a group combining any of these. Even more preferred is at least one structure (i-1a) selected from the group consisting of a benzene ring, a naphthalene ring, an anthracene ring, a pyrene ring, a fluorene ring, a biphenyl ring, methane, ethane, a phthalimide structure, a benzoisoquinoline-1,3-dione structure, and a pyromellitic diimide structure, or a structure obtained by combining the structure (i-1a) with -CO-, -NH-, -O- or a group combining any of these. When W ３ includes an imide ring-containing structure, it is preferable that the nitrogen atom in the imide ring-containing structure is bonded to a carbon atom of Ar １ in the above formula (A1-6).

[0042] Specific examples of compounds represented by the above formula (A1-1) include, but are not limited to, compounds represented by the following formula.

[0043]

[0044]

[0045] Specific examples of compounds represented by the above formula (A1-2) include, but are not limited to, compounds represented by the following formula.

[0046]

[0047] The compounds represented by the above formula (A1-3) are not limited to those represented by the following formulas.

[0048]

[0049] Specific examples of compounds represented by the above formula (A1-4) include, but are not limited to, compounds represented by the following formula.

[0050]

[0051] Specific examples of polymers having repeating units represented by the above formula (A1-5) include, but are not limited to, polymers having repeating units represented by the following formula.

[0052]

[0053] Specific examples of polymers having the repeating units represented by (A1-6) above include, but are not limited to, polymers having the repeating units represented by the following formula.

[0054]

[0055] The molecular weight of compound [A] is 210 or more, regardless of whether compound [A] is a polymer or a low molecular weight compound without repeating units. When compound [A] is a low molecular weight compound, the lower limit of the molecular weight of compound [A] is more preferably 220, and even more preferably 230. The upper limit of the molecular weight is preferably 1400, and even more preferably 1200. When compound [A] is a polymer, the lower limit of the molecular weight of compound [A] is preferably 2000, and even more preferably 3000. The upper limit of the molecular weight of compound [A] is preferably 10000, and even more preferably 8000. When compound [A] is a low molecular weight compound, the molecular weight is the value obtained from the structural formula. When compound [A] is a polymer, the molecular weight is the weight-average molecular weight measured by gel permeation chromatography using monodisperse polystyrene as the standard.

[0056] Preferably, the content of compound [A] in the components other than the solvent in the above resist underlayer film forming composition is 0.5% by mass or more. The above content of compound [A] may be 5% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 100% by mass.

[0057] <Method for Producing Compound [A]> The method for producing Compound [A] is not particularly limited, but typically involves preparing an anthraquinone raw material having a reactive functional group (e.g., hydroxyl group, amino group, carboxyl group, sulfanyl group, formyl group, etc.) and carrying out known reactions such as esterification, (thio) etherification, nucleophilic amination, amidation, imidation, and acid addition condensation. Whether Compound [A] takes the form of a low molecular weight or a polymer can be controlled by the number and type of reactive functional groups present in the anthraquinone raw material and the reaction substrate that reacts with it. The anthraquinone raw material may be used as Compound [A] as is. A commercially available product may be used as Compound [A]. After the reaction, Compound [A] can be obtained by separation, purification, drying, etc. As the reaction solvent, Solvent [B] described later can be suitably used.

[0058] <[B] Solvent> The [B] solvent is not particularly limited as long as it can dissolve or disperse the [A] compound and any optional components contained therein as needed.

[0059] [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.

[0060] 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.

[0061] 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, polyhydric alcohol partial ether carboxylate solvents such as diethylene glycol acetate monomethyl ether and propylene glycol acetate monomethyl ether, and lactate ester solvents such as methyl lactate and ethyl lactate.

[0062] Examples of alcohol-based solvents include monoalcohol solvents such as methanol, ethanol, n-propanol, and 1-butanol, and polyhydric alcohol solvents such as ethylene glycol and 1,2-propylene glycol.

[0063] Examples of ketone solvents include linear ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, and cyclic ketone solvents such as cyclohexanone.

[0064] Examples of ether-based solvents include linear ether solvents such as n-butyl ether, cyclic ether solvents such as tetrahydrofuran and dioxane, polyhydric alcohol ether solvents such as ethylene glycol dimethyl ether, and polyhydric alcohol partial ether solvents such as diethylene glycol monomethyl ether.

[0065] Examples of nitrogen-containing solvents include linear nitrogen-containing solvents such as N,N-dimethylacetamide and N,N-dimethylformamide, and cyclic nitrogen-containing solvents such as N-methyl-2-pyrrolidone.

[0066] [B] As the solvent, ester solvents or ketone solvents are preferred, polyhydric alcohol partial ether carboxylate solvents or cyclic ketone solvents are more preferred, and propylene glycol acetate monomethyl ether or cyclohexanone is even more preferred.

[0067] The lower limit of the content of solvent [B] in the resist underlayer film forming composition is preferably 50% by mass, more preferably 60% by mass, and still more preferably 70% by mass. The upper limit of the above content is preferably 99.9% by mass, more preferably 99% by mass, and still more preferably 98% by mass.

[0068] [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 aromatic ring-containing compounds with a molecular weight of 500 or more that are different from compound [A], acid generators, crosslinking agents, surfactants, defoamers, base generators, etc. The aromatic ring-containing compounds are not particularly limited as long as they have a molecular weight of 500 or more and contain an aromatic ring, and examples include novolac polymers, polyimides, (meth)acrylic polymers having an aromatic ring in the side chain, fluorene derivatives, aromatic rings having a phenolic hydroxyl group and their derivatives (e.g., oligomers, calixarenes, etc.). As defoamers, known defoamers can be used, and examples include alcohol defoamers, phosphate ester defoamers, fatty acid ester defoamers, polyether defoamers, silicone defoamers, etc. 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.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.). The 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 according to the type of optional component, etc.

[0069] [Method for preparing the composition] The resist underlayer film forming composition can be prepared by mixing [A] compound, [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.

[0070] 《Method for Manufacturing Semiconductor Substrates》 The method for manufacturing the semiconductor substrate includes a step of directly or indirectly coating a resist underlayer film formation composition onto a substrate (hereinafter also referred to as the "coating step"), a step of directly or indirectly forming a resist pattern onto the resist underlayer film formed by the coating step (hereinafter also referred to as the "resist pattern formation step"), and a step of performing etching using the resist pattern as a mask (hereinafter also referred to as the "etching step").

[0071] The method for manufacturing the semiconductor substrate may further include, if necessary, a step of heating the resist underlayer film formed by the coating step before the resist pattern formation step (hereinafter also referred to as the "heating step").

[0072] The method for manufacturing the semiconductor substrate may further include, if necessary, a step of forming a silicon-containing film directly or indirectly on the resist underlayer film before forming the resist pattern (hereinafter also referred to as the "silicon-containing film formation step").

[0073] The following describes the resist underlayer film formation composition used in the semiconductor substrate manufacturing method, as well as each step when the optional steps, such as the heating step and the silicon-containing film formation step, are included.

[0074] [Coating Process] In this process, the resist underlayer film formation composition is coated directly or indirectly onto the substrate. In this process, the resist underlayer film formation composition described above is used.

[0075] The coating method for the resist underlayer film 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 film is formed when the solvent [B] volatilizes.

[0076] Examples of substrates include metal or metalloid substrates such as silicon substrates, aluminum substrates, nickel substrates, chromium substrates, molybdenum substrates, tungsten substrates, copper substrates, tantalum substrates, and titanium substrates, with silicon substrates being preferred among these. The above substrates may also be substrates on which silicon nitride films, alumina films, silicon dioxide films, tantalum nitride films, titanium nitride films, etc., are formed.

[0077] The substrate may have patterns. The resist underlayer film forming composition has excellent embedding properties, so even if the substrate has patterns, it can form a good film while filling the gaps between patterns. Examples of the pattern shapes include trench patterns, line-and-space patterns, hole patterns, and pillar patterns. Examples of trench patterns and line-and-space patterns include patterns containing recesses with a width of 5 nm to 100 nm and patterns containing recesses with a depth of 5 nm to 500 nm. Examples of hole patterns include patterns containing holes with a diameter of 5 nm to 100 nm and patterns containing holes with a depth of 5 nm to 500 nm. Examples of pillar patterns include patterns containing pillars with a width of 5 nm to 100 nm and patterns containing pillars with a height of 5 nm to 500 nm.

[0078] Examples of indirectly coating a substrate with a resist underlayer film formation composition include coating a low-dielectric insulating film or an organic underlayer film formed on the substrate with the resist underlayer film formation composition.

[0079] [Heating Process] In this process, the coated film formed by the above coating process is heated. Heating the coated film promotes the formation of the resist underlayer film. More specifically, heating the coated film promotes the volatilization of solvent [B], etc.

[0080] The above-mentioned coating film may be heated under an atmospheric environment or under a nitrogen atmosphere. The lower limit of the heating temperature is preferably 250°C, and more preferably 300°C. The upper limit of the heating temperature is preferably 600°C, and more preferably 500°C. The lower limit of the heating time is preferably 15 seconds, and more preferably 30 seconds. The upper limit of the heating time is preferably 1,200 seconds, and more preferably 600 seconds.

[0081] Furthermore, the resist underlayer film may be exposed after the above coating step. Plasma may be exposed to the resist underlayer film after the above coating step. Ion implantation may be performed into the resist underlayer film after the above coating step. Exposing the resist underlayer film improves the etching resistance of the resist underlayer film. Exposing the resist underlayer film to plasma improves the etching resistance of the resist underlayer film. Performing ion implantation into the resist underlayer film improves the etching resistance of the resist underlayer film.

[0082] The radiation used for exposing the resist underlayer film is appropriately selected from electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, X-rays and γ-rays; and particle beams such as electron beams, molecular beams and ion beams.

[0083] Examples of the method for exposing the resist underlayer film to plasma include a direct method in which a substrate is placed in each gas atmosphere and subjected to plasma discharge. As conditions for the plasma exposure, the gas flow rate is usually 50 cc / min or more and 100 cc / min or less, and the supplied power is 100 W or more and 1,500 W or less.

[0084] As the lower limit of the plasma exposure time, 10 seconds is preferable, 30 seconds is more preferable, and 1 minute is further preferable. As the upper limit of the above time, 10 minutes is preferable, 5 minutes is more preferable, and 2 minutes is further preferable.

[0085] Plasma is generated, for example, in an atmosphere of a mixed gas of H ２ gas and Ar gas. Further, in addition to H ２ gas and Ar gas, CF ４ gas and CH ４ gas and other carbon-containing gases may be introduced. Note that instead of one or both of H ２ gas and Ar gas, CF ４ gas, NF ３ gas, CHF ３ gas, CO ２ gas, CH ２ F ２ gas, CH ４ gas and C ４ F ８ gas, at least one of these may be introduced.

[0086] Ion implantation into the resist underlayer involves implanting dopants into the resist underlayer. Dopants can be selected from a group consisting of boron, carbon, nitrogen, phosphorus, arsenic, aluminum, and tungsten. The implantation energy used to apply voltage to the dopant ranges from approximately 0.5 keV to 60 keV, depending on the type of dopant used and the desired implantation depth.

[0087] The lower limit of the average thickness of the resist underlayer film formed is preferably 30 nm, more preferably 50 nm, and even more preferably 60 nm. The upper limit of the average thickness is preferably 3,000 nm, more preferably 2,000 nm, and even more preferably 500 nm. The method for measuring the average thickness is as described in the examples.

[0088] [Silicon-containing film formation process] In this process, a silicon-containing film is formed directly or indirectly on the resist underlayer film formed by the coating process or the heating process described above. An example of indirect formation of a silicon-containing film on the resist underlayer film is when a surface modification film of the resist underlayer film is formed on the resist underlayer film. The surface modification film of the resist underlayer film is, for example, a film whose contact angle with water is different from that of the resist underlayer film.

[0089] Silicon-containing films can be formed by coating with a silicon-containing film-forming composition, chemical vapor deposition (CVD), atomic layer deposition (ALD), etc. A method for forming a silicon-containing film by coating with a silicon-containing film-forming composition includes, for example, directly or indirectly coating the resist underlayer with the silicon-containing film-forming composition, and then curing the resulting coated film by exposure and / or heating. Commercially available silicon-containing film-forming compositions include, for example, "NFC SOG01," "NFC SOG04," and "NFC SOG080" (all manufactured by JSR Corporation). Silicon oxide films, silicon nitride films, silicon oxidnitride films, and amorphous silicon films can be formed by chemical vapor deposition (CVD) or atomic layer deposition (ALD).

[0090] Examples of radiation used in the above exposure include electromagnetic waves such as visible light, ultraviolet rays, far ultraviolet rays, X-rays, and gamma rays, as well as particle beams such as electron beams, molecular beams, and ion beams.

[0091] The lower limit of the temperature when heating the coating film is preferably 90°C, more preferably 150°C, and even more preferably 180°C. The upper limit of the above temperature is preferably 550°C, more preferably 450°C, and even more preferably 320°C. Heating may be carried out in stages.

[0092] The lower limit of the average thickness of the silicon-containing film is preferably 1 nm, more preferably 10 nm, and even more preferably 20 nm. The upper limit is preferably 20,000 nm, more preferably 1,000 nm, and even more preferably 100 nm. The average thickness of the silicon-containing film is the value measured using the spectroscopic ellipsometer, similar to the average thickness of the resist underlayer film.

[0093] [Resist Pattern Formation Process] In this process, a resist pattern is formed directly or indirectly on the resist underlayer film. Methods for performing this process include, for example, using a resist composition, using a nanoimprint method, or using a self-assembled composition. An example of indirectly forming a resist pattern on the resist underlayer film is forming a resist pattern on the silicon-containing film.

[0094] Examples of the above-mentioned resist compositions 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 compositions containing metals such as tin, zirconium, and hafnium.

[0095] Examples of coating methods for the resist composition include rotary coating. The pre-baking temperature and time can be appropriately adjusted depending on the type of resist composition used.

[0096] Next, the resist film formed above is exposed by selective radiation irradiation. The radiation used for exposure can be appropriately selected depending on the type of radiation-sensitive acid generator used in the resist composition, and examples include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, X-rays, and gamma rays, as well as particle beams such as electron beams, molecular beams, and ion beams. Among these, far ultraviolet light is preferred, and KrF excimer laser light (wavelength 248 nm), ArF excimer laser light (wavelength 193 nm), F ２ Excimer 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, etc., hereinafter also referred to as "EUV") is more preferred, and KrF excimer laser light, ArF excimer laser light, or EUV is even more preferred.

[0097] After the exposure described above, post-baking can be performed to improve resolution, pattern profile, developability, etc. The temperature and time of this post-baking can be appropriately determined depending on the type of resist composition used, etc.

[0098] Next, the exposed resist film is developed with a developer to form a resist pattern. This development may be alkaline development or organic solvent development. Examples of developers for alkaline development include basic aqueous solutions such as ammonia, triethanolamine, tetramethylammonium hydroxide (TMAH), and tetraethylammonium hydroxide. These basic aqueous solutions may also have appropriate amounts of water-soluble organic solvents such as methanol and ethanol, or surfactants added to them. For organic solvent development, examples of developers include the various organic solvents exemplified as solvent [B] in the resist underlayer film forming composition described above.

[0099] After development with the above-mentioned developer, the resist pattern is formed by washing and drying.

[0100] [Etching Process] In this process, etching is performed using the resist pattern described above as a mask. The etching may be performed once or multiple times, i.e., sequentially using the pattern obtained by etching as a mask. From the viewpoint of obtaining a pattern with a better shape, multiple etchings are preferred. When multiple etchings are performed, for example, the silicon-containing film, the resist underlayer film, and the substrate are etched sequentially. Examples of etching methods include dry etching and wet etching. From the viewpoint of obtaining a better shape for the substrate pattern, dry etching is preferred. For this dry etching, for example, a gas plasma such as oxygen plasma is used. By performing the above etching, a semiconductor substrate having a predetermined pattern is obtained.

[0101] Dry etching can be performed, for example, using a known dry etching apparatus. The etching gas used for dry etching can be appropriately selected depending on the mask pattern, the elemental composition of the film to be etched, etc., for example, CHF ３ CF ４ , C ２ F ６ , C ３ F ８ SF ６ Fluorine-based gases such as Cl ２ , BCl ３ Chlorine-based gases such as O ２ , O ３ , H ２ Oxygen-based gases such as O, H ２ CO, CO ２ ,CH ４ , C ２ H ２ , C ２ H ４ , C ２ H ６ , C ３ H ４ , C ３ H ６ , C ３ H ８ , HF, HI, HBr, HCl, NO, NH ３ , BCl ３ Reducing gases such as He, N ２Examples include inert gases such as Ar. These gases can also be used in mixtures. When etching a substrate using the pattern of the resist underlayer as a mask, fluorine-based gases are usually used.

[0102] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0103] [Weight-average molecular weight (Mw)] The Mw of the polymer was measured by gel permeation chromatography (detector: differential refractometer) using monodisperse polystyrene as the standard, under analytical conditions of flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, column temperature: 40°C, using GPC columns from Tosoh Corporation (two "G2000HXL" columns and one "G3000HXL" column).

[0104] [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.

[0105] <Synthesis of Compounds [A] and Compounds [A]> Compounds (A-1) to (A-10), represented by the following formulas (A-1) to (A-10), were commercially available products. Compounds (A-11) to (A-12), represented by the following formulas (A-11) to (A-12), and polymers (A-13) to (A-17), which have repeating units, were synthesized by the following procedures.

[0106]

[0107]

[0108]

[0109]

[0110] [Example 1-1] (Synthesis of Compound (A-11)) 20.00 g of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride and 20.87 g of 1-amino-4-hydroxyanthraquinone were added to 120 g of N-methyl-2-pyrrolidone, and the mixture was reacted at 40°C for 3 hours under a nitrogen atmosphere. 8.28 g of pyridine was added to the resulting reaction solution, and then 13.36 g of acetic anhydride was added dropwise, and the mixture was reacted at 60°C for 4 hours. After the reaction was complete, the mixture was cooled to room temperature, 400 g of methyl isobutyl ketone was added, and the organic layer was washed twice with 300 g of 3% aqueous nitric acid solution, then washed six times with 300 g of pure water, and the organic layer was dried under reduced pressure. 120 g of tetrahydrofuran (THF) was added, and the mixture was immersed in methanol for reprecipitation. The precipitate was filtered off, washed twice with 300 g of methanol, and then vacuum dried at 70°C to obtain compound (A-11).

[0111] [Example 1-2] (Synthesis of Compound (A-12)) Compound (A-12) was obtained as the product under the same reaction conditions as in Example 1-1, except that 19.87 g of 1-aminoanthraquinone was used instead of 1-amino-4-hydroxyanthraquinone.

[0112] [Example 1-3] (Synthesis of polymer (A-13)) Polymer (A-13) was obtained as the product under the same reaction conditions as in Example 1-1, except that 20.79 g of 1,4-diaminoanthraquinone was used instead of 1-amino-4-hydroxyanthraquinone. The Mw of polymer (A-13) was 4200.

[0113] [Example 1-4] (Synthesis of polymer (A-14)) Under a nitrogen atmosphere, 160 g of THF and 4.49 g of magnesium were charged into a reaction vessel, and 22.16 g of α,α'-dibromo-p-xylene was added dropwise. The mixture was then reacted at 40°C for 1 hour. 20.00 g of 1,4-diaminoanthraquinone was added to the resulting reaction solution, and the mixture was reacted under reflux for 12 hours. After the reaction was complete, the mixture was cooled to room temperature, the residue was filtered, and 500 g of methyl isobutyl ketone was added. The organic layer was washed twice with 300 g of 3% aqueous nitric acid solution, and then washed six times with 300 g of pure water. The organic layer was dried under reduced pressure. 120 g of THF was added, and the mixture was immersed in methanol for reprecipitation. The precipitate was filtered off, washed twice with 300 g of methanol, and then vacuum dried at 70°C to obtain polymer (A-14). The Mw of polymer (A-14) was 3700.

[0114] [Example 1-5] (Synthesis of polymer (A-15)) Polymer (A-15) was obtained as the product under the same reaction conditions as in Example 1-4, except that 20.00 g of 1,4-dihydroxyanthraquinone was used instead of 1,4-diaminoanthraquinone. The Mw of polymer (A-15) was 5200.

[0115] [Example 1-6] (Synthesis of polymer (A-16)) In a reaction vessel, under a nitrogen atmosphere, 20.0 g of 1-hydroxypyrene, 20.56 g of 2-anthraquinone aldehyde, and 150 g of 1-propoxy-2-propanol were added and heated to 80°C. Then, 8.80 g of methanesulfonic acid was slowly added dropwise, and the mixture was reacted at 120°C for 20 hours. After the reaction was complete, the reaction solution was transferred to a separatory funnel, and the organic phase was washed with 500 g of methyl isobutyl ketone, 200 g of cyclohexanone, and 500 g of 1% oxalic acid solution. After separating the aqueous phase, the obtained organic phase was washed several times with water. Then, it was concentrated in an evaporator, and the residue was added dropwise to 400 g of diisopropyl ether to obtain a precipitate. The precipitate was collected by suction filtration and washed several times with 200 g of diisopropyl ether. Then, polymer (A-16) was obtained by drying in a vacuum dryer at 60°C for 12 hours. The Mw of polymer (A-16) was 4800.

[0116] [Example 1-7] (Synthesis of polymer (A-17)) Polymer (A-17) was obtained as the product under the same reaction conditions as in Example 1-6, except that 31.23 g of 9,9-bis(4-hydroxyphenyl)fluorene was used instead of 1-hydroxypyrene. The Mw of polymer (A-17) was 6500.

[0117] [Comparative Synthesis Example 1-1] (Synthesis of Polymer (x-1)) In a reaction vessel, under a nitrogen atmosphere, 250.0 g of m-cresol, 125.0 g of 37% by mass formalin, and 2 g of oxalic anhydride were added. The mixture was reacted at 100°C for 3 hours and then at 180°C for 1 hour. After that, unreacted monomers were removed under reduced pressure to obtain polymer (x-1) represented by the following formula (x-1). The Mw of the obtained polymer (x-1) was 11,000.

[0118]

[0119] <Preparation of composition for forming a resist underlayer film> The following describes the compounds [A], [B], [C], [D], acid generator, [E], crosslinking agent, and other components used in the preparation of the composition for forming a resist underlayer film (hereinafter also referred to as "the composition").

[0120] [[A] Compounds] A-1 to A-17: The synthesized compounds (A-1) to (A-12) and polymers (A-13) to (A-17) described above.

[0121] [[B] Compounds] B-1 to B-34: Compounds (B-1) to (B-34) represented by the following formulas. (In the formulas below, the numbers in parentheses around the repeating units indicate the content (mol%) of each repeating unit. R represents a hydrogen atom or a propargyl group. * represents the bond with the oxygen atom in the -OR in the formula.)

[0122]

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129] [C Solvent] C-1: Propylene glycol monomethyl ether acetate C-2: Cyclohexanone

[0130] [[D] Acid Generator] D-1: Compound represented by the following formula (D-1)

[0131] [E] Crosslinking agent E-1: Compound represented by the following formula (E-1) E-2: Compound represented by the following formula (E-2)

[0132] [Other components] x-1: The polymer synthesized above (x-1) x-2: The compound represented by the following formula (x-2) x-3: The compound represented by the following formula (x-3)

[0133] [Example 2-1] 30 parts by mass of (A-1) as compound [A] and 70 parts by mass of (B-1) as compound [B] were dissolved in 3300 parts by mass of (C-1) as solvent [B]. The resulting solution was filtered through a polytetrafluoroethylene (PTFE) membrane filter with a pore size of 0.45 μm to prepare composition (J-1).

[0134] [Examples 2-2 to 2-63 and Comparative Examples 2-1 to 2-3] Compositions (J-2) to (J-63) and (CJ-1) to (CJ-3) were prepared in the same manner as in Example 2-1, except that the types and amounts of each component shown in Tables 1-1 to 1-3 below were used. A "-" in Tables 1-1 to 1-3 indicates that the corresponding component was not used.

[0135]

[0136]

[0137]

[0138] <Evaluation> [Examples 3-1 to 3-63 and Comparative Examples 3-1 to 3-3] The embedding properties and bending resistance were evaluated using the above-prepared resist underlayer film forming compositions by the following methods. The evaluation results are shown in Tables 3-1 to 3-3 below.

[0139] [Embedding Properties] The above resist underlayer film formation composition was applied to a substrate on which trench patterns with a depth of 65 nm and widths of 20 nm and 30 nm were formed, using a spin coater (LITHIUS Pro Z from Tokyo Electron Limited) by rotary coating. The rotation conditions of the spin coater were set to obtain a film-coated substrate with an average thickness of 100 nm. Next, the substrate was heated at 400°C for 90 seconds in an air atmosphere, and then cooled at 23°C for 60 seconds. The cross-sectional shape of the substrate was observed (200,000x magnification) using a scanning electron microscope (S-4800 from Hitachi High-Technologies Corporation) to evaluate its embedding properties. The embedding performance was evaluated as follows: "A" (good) if the resist underlayer film was embedded to the bottom of the 20 nm wide trench pattern on the substrate; "B" (fairly good) if it was not embedded to the bottom of the 20 nm wide trench pattern but was embedded to the bottom of the 30 nm wide trench pattern; and "C" (poor) if it was not embedded to the bottom of the 30 nm wide trench pattern.

[0140] [Bending Resistance] The above-prepared composition was coated onto a silicon substrate on which a silicon dioxide film with an average thickness of 500 nm had been formed, using a spin coater (CLEAN TRACK ACT12 from Tokyo Electron Limited) by rotary coating. Next, the substrate was heated at 350°C for 60 seconds in an air atmosphere, and then cooled at 23°C for 60 seconds to obtain a film-coated substrate on which a resist underlayer film with an average thickness of 200 nm had been formed. On the above-prepared film-coated substrate, a silicon-containing film-forming composition (NFC SOG080 from JSR Corporation) was coated by rotary coating, and then heated at 200°C for 60 seconds in an air atmosphere, and further heated at 300°C for 60 seconds to form a silicon-containing film with an average thickness of 50 nm. An ArF resist composition (AR1682J from JSR Corporation) was coated onto the silicon-containing film using a rotary coating method, and the resist film was heated (fired) at 130°C for 60 seconds in an air atmosphere to form a resist film with an average thickness of 200 nm. The resist film was exposed using an ArF excimer laser exposure apparatus (lens numerical aperture 0.78, exposure wavelength 193 nm) through a 1:1 line-and-space mask pattern with a target size of 100 nm, with varying exposure levels. After exposure, the resist film was heated (fired) at 130°C for 60 seconds in an air atmosphere, developed at 25°C for 1 minute using a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH), washed with water, and dried to obtain a substrate on which a line-and-space resist pattern with a 200 nm pitch and line widths ranging from 30 nm to 100 nm was formed.

[0141] Using the above resist pattern as a mask, the above etching apparatus is used to process CF ４ Under the conditions of =200 sccm, PRESS. =85 mT, HF RF (high-frequency power for plasma generation) =500 W, LF RF (high-frequency power for bias) =0 W, DCS = -150 V, and RDC (gas center flow rate ratio) =50%, a silicon-containing film was etched to obtain a substrate with a pattern formed on the silicon-containing film. Next, using the silicon-containing film pattern as a mask, the etching apparatus was used to etch O ２Under the conditions of =400 sccm, PRESS. =25 mT, HF RF (high-frequency power for plasma generation) =400 W, LF RF (high-frequency power for bias) =0 W, DCS =0 V, and RDC (gas center flow rate ratio) =50%, the resist underlayer film was etched to obtain a substrate with a pattern formed on the resist underlayer film. Using the above resist underlayer film pattern as a mask, the above etching apparatus was used to CF ４ Under the conditions of 180 sccm, Ar = 360 sccm, PRESS. = 150 mT, HF RF (high-frequency power for plasma generation) = 1,000 W, LF RF (high-frequency power for bias) = ​​1,000 W, DCS = -150 V, RDC (gas center flow rate ratio) = 50%, and 60 seconds, a silicon dioxide film was etched to obtain a substrate with a pattern formed on the silicon dioxide film.

[0142] Subsequently, for the substrate on which the silicon dioxide film pattern was formed, images of the shape of the resist underlayer film pattern for each line width were obtained by magnifying 250,000 times using a scanning electron microscope (Hitachi High-Technologies Corporation's "CG-4000"). By processing these images, as shown in Figure 1, the LER (line edge roughness) was defined as the standard deviation of 3 times the average position Xa calculated from the position Xn (n=1 to 10) in the line width direction, which was measured at 10 locations at 100 nm intervals on the lateral surface 3a of the resist underlayer film pattern 3 (line pattern) with a length of 1,000 nm, and the average position Xa of these positions in the line width direction. The LER, which indicates the degree of curvature of the resist underlayer film pattern, increases as the line width of the resist underlayer film pattern becomes narrower. Bending resistance was evaluated as follows: "A" (good) if the line width of the film pattern with a LER of 5.5 nm was less than 40.0 nm; "B" (fairly good) if it was between 40.0 nm and 45.0 nm; and "C" (poor) if it was 45.0 nm or more. Note that the degree of bending of the film pattern shown in Figure 1 is exaggerated compared to the actual degree.

[0143]

[0144]

[0145]

[0146] As can be seen from the results in Tables 3-1 to 3-3, the compositions of the examples and the resist underlayer films formed from these compositions exhibited superior embedding properties and bending resistance compared to the comparative examples.

[0147] The semiconductor substrate manufacturing method of the present invention makes it possible to form a resist underlayer film that not only has excellent embedding properties that can sufficiently fill the substrate pattern, but also has excellent bending resistance. The resist underlayer film forming composition of the present invention makes it possible to form a resist underlayer film that has excellent embedding properties and bending resistance. Therefore, these can be suitably used in the manufacture of semiconductor devices, for which further miniaturization is expected in the future.

[0148] 3. Resist underlayer pattern 3a. Side view of the resist underlayer pattern

Claims

1. A composition for forming a resist underlayer film, comprising a carbonyl group-containing compound and a solvent, wherein the carbonyl group-containing compound has a molecular weight of 210 or more and has a partial structure represented by the following formula (A1). (In the above formula (A1), Ar １ and Ar ２ are each independently an aromatic ring having 6 to 20 carbon atoms. p is an integer of 0 to 4. q is an integer of 0 to 4. When p is 2 or more, a plurality of R １ are the same or different. When q is 2 or more, a plurality of R ２ are the same or different. R １ is a hydroxy group, a nitro group, an amino group, a sulfanyl group, a halogen atom or a monovalent organic group having 1 to 20 carbon atoms, or when a plurality of R １ are present, two of the plurality of R １ are combined with each other to form a ring structure having 3 to 20 carbon atoms together with the two carbon atoms of Ar １ to which they are bonded. R ２ is a hydroxy group, a nitro group, an amino group, a sulfanyl group, a halogen atom or a monovalent organic group having 1 to 20 carbon atoms, or when a plurality of R ２ are present, two of the plurality of R ２ are combined with each other to form a ring structure having 3 to 20 carbon atoms together with the two carbon atoms of Ar ２ to which they are bonded. * is a bonding site with another atom constituting the carbonyl group-containing compound. ** is a bonding site with another atom constituting the carbonyl group-containing compound. n is an integer of 0 to 4. m is an integer of 0 to 4.) 2. The resist underlayer film forming composition according to claim 1, wherein the carbonyl group-containing compound is a compound represented by the following formula (A1-1), a compound represented by the following formula (A1-2), a compound represented by the following formula (A1-3), a compound represented by the following formula (A1-4), a polymer having a repeating unit represented by the following formula (A1-5), or a polymer having a repeating unit represented by the following formula (A1-6). (In the above formulas (A1-1) to (A1-6), Ar １ Ar ２ , R １ , R ２ , p and q are equivalent to those in the above formula (A1). Ar １ Ar ２ , R １ , R ２ If there are multiple instances of p, q, X, and Y, then there are multiple Ar １ Ar ２ , R １ , R ２ p, q, X, and Y are either identical or different from each other. １ is a u-valent organic group having 1 to 40 carbon atoms. u is an integer from 1 to 4. X and Y are independently a single bond, an oxygen atom, -NH-, -CO-, or a divalent organic group. s is 1 or 2. W ２ This is a divalent organic group having 1 to 40 carbon atoms. ３ (L is a divalent organic group with 1 to 40 carbon atoms. L is a single bond or a divalent organic group with 1 to 10 carbon atoms.) 3. Ar １ and Ar ２ The resist underlayer film forming composition according to claim 1 or claim 2, wherein each is independently a benzene ring or a naphthalene ring.

4. The resist underlayer film forming composition according to claim 1 or claim 2, wherein the content of the carbonyl group-containing compound in the components other than the solvent in the resist underlayer film forming composition is 0.5% by mass or more.

5. The resist underlayer film forming composition according to claim 1 or claim 2, further comprising an aromatic ring-containing compound having a molecular weight of 500 or more, which is different from the carbonyl group-containing compound described above.

6. A method for manufacturing a semiconductor substrate, comprising the steps of: coating a substrate directly or indirectly with a resist underlayer film forming composition; directly or indirectly forming a resist pattern on the resist underlayer film formed by the coating step; and etching using the resist pattern as a mask, wherein the resist underlayer film forming composition contains a carbonyl group-containing compound and a solvent, and the carbonyl group-containing compound has a molecular weight of 210 or more and has a substructure represented by the following formula (A1). (In the above formula (A1), Ar １ and Ar ２ Each of these is an independent aromatic ring with 6 to 20 carbon atoms. p is an integer from 0 to 4. q is an integer from 0 to 4. If p is 2 or greater, multiple R １ They are the same or different. If q is 2 or more, there are multiple R ２ They are either the same or different. １ is a hydroxyl group, nitro group, amino group, sulfanyl group, halogen atom, or monovalent organic group having 1 to 20 carbon atoms, or R １ If multiple R １ Two of them can be combined and joined together as Ar １ It forms a ring structure with 3 to 20 carbon atoms together with the two carbon atoms. ２ is a hydroxyl group, nitro group, amino group, sulfanyl group, halogen atom, or monovalent organic group having 1 to 20 carbon atoms, or R ２ If multiple R ２ Two of them can be combined and joined together as Ar ２ It forms a ring structure with 3 to 20 carbon atoms together with the two carbon atoms. * indicates a bonding site with other atoms constituting the carbonyl group-containing compound. ** indicates a bonding site with other atoms constituting the carbonyl group-containing compound. n is an integer from 0 to 4. m is an integer from 0 to 4.

7. The method for producing a semiconductor substrate according to claim 6, wherein the carbonyl group-containing compound is a compound represented by the following formula (A1-1), a compound represented by the following formula (A1-2), a compound represented by the following formula (A1-3), a compound represented by the following formula (A1-4), a polymer having a repeating unit represented by the following formula (A1-5), or a polymer having a repeating unit represented by the following formula (A1-6). (In the above formulas (A1-1) to (A1-6), Ar １ Ar ２ , R １ , R ２ , p and q are equivalent to those in the above formula (A1). Ar １ Ar ２ , R １ , R ２ If there are multiple instances of p, q, X, and Y, then there are multiple Ar １ Ar ２ , R １ , R ２ p, q, X, and Y are either identical or different from each other. １ is a u-valent organic group having 1 to 40 carbon atoms. u is an integer from 1 to 4. X and Y are independently a single bond, an oxygen atom, -NH-, -CO-, or a divalent organic group. s is independently 1 or 2. W ２ This is a divalent organic group having 1 to 40 carbon atoms. ３ (L is a divalent organic group with 1 to 40 carbon atoms. L is a single bond or a divalent organic group with 1 to 10 carbon atoms.) 8. Ar １ and Ar ２ The method for manufacturing a semiconductor substrate according to claim 6 or claim 7, wherein each of them is independently a benzene ring or a naphthalene ring.

9. The method for producing a semiconductor substrate according to claim 6 or claim 7, wherein the content of the carbonyl group-containing compound in the components other than the solvent in the resist underlayer film-forming composition is 0.5% by mass or more.

10. A method for manufacturing a semiconductor substrate according to claim 6 or claim 7, further comprising the step of forming a silicon-containing film directly or indirectly on the resist underlayer film before forming the resist pattern described above.

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