Resist underlayer film formation composition and production method for semiconductor substrate

Abstract

Provided are a resist underlayer film formation composition that makes it possible to form a film that has excellent flatness and embedding properties and a production method for a semiconductor substrate. A resist underlayer film formation composition according to the present invention contains a carbonyl group–containing compound and a solvent, the carbonyl group–containing compound having at least one partial structure selected from the group that consists of partial structures represented by formula (A1) and partial structures represented by formula (A2). (In the formulas, Ar1 and Ar2 are a C3–20 aromatic ring, R1 is a hydroxyl group, a nitro group, a halogen atom, or a C1–20 monovalent organic group, n is 1 or 2, p is an integer from 0 to 4, inclusive, and * is the site of a bond to another partial structure of the carbonyl group–containing compound, and in formula (A1), one of Y1and Y2 is a carbonyl group, and the other is a single bond, an oxygen atom, a sulfur atom, or a methylene group.)

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 compositions for forming the resist underlayer film are required to have both the ability to embed sufficiently into the substrate pattern and the ability to form a flat film regardless of the presence or absence of the pattern.

[0006] The present invention has been made based on the circumstances described above, and its purpose is to provide a resist underlayer film formation composition capable of forming a film with excellent embedding properties and flatness, and a method for manufacturing a semiconductor substrate.

[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 at least one substructure selected from the group consisting of a substructure represented by the following formula (A1) and a substructure represented by the following formula (A2). (In the above formulas (A1) and (A2), Ar １ and Ar ２is, independently, an aromatic ring having 3 to 20 carbon atoms. R １ is, independently, a hydroxy group, a nitro group, a halogen atom or a monovalent organic group having 1 to 20 carbon atoms. R １ When there are a plurality of R １ are the same as or different from each other. In the above formula (A1), Y １ or Y ２ One of them is a carbonyl group, and the other is a single bond, an oxygen atom, a sulfur atom or a methylene group. n is, independently, 1 or 2. p is, independently, an integer of 0 to 4. * is a bonding site with another partial structure in the above carbonyl group-containing compound.)

[0008] Since the composition for forming a resist underlayer film contains the [A] compound, a resist underlayer film excellent in embedding property and flatness can be formed. Although the reason is not clear, it is presumed as follows. The [A] compound has a carbonyl group having polarity together with an aromatic ring, and a structure that is rigid and has affinity for a solvent, a substrate, etc. is introduced. Thereby, the heat resistance and film quality homogeneity of the [A] compound can be improved, and as a result, it is presumed that the composition for forming a resist underlayer film can form a resist underlayer film excellent in embedding property and flatness.

[0009] In another embodiment of the present invention, a step of applying a composition for forming a resist underlayer film directly or indirectly on a substrate, a step of forming a resist pattern directly or indirectly on the resist underlayer film formed by the above coating step, and a step of performing etching using the resist pattern as a mask, and the composition for forming a resist underlayer film contains a carbonyl group-containing compound and a solvent, and the carbonyl group-containing compound has at least one partial structure selected from the group consisting of a partial structure represented by the following formula (A1) and a partial structure represented by the following formula (A2). The present invention relates to a method for manufacturing a semiconductor substrate. (In the above formula (A1) and the above formula (A2), Ar １ and Ar ２ are, independently, an aromatic ring having 3 to 20 carbon atoms. R １Each of these is independently a hydroxyl group, a nitro group, a halogen atom, or a monovalent organic group having 1 to 20 carbon atoms. １ If multiple R １ These are either identical or different from each other. In the above formula (A1), Y １ or Y ２ One of the components is a carbonyl group, and the other is a single bond, an oxygen atom, a sulfur atom, or a methylene group. n is independently 1 or 2. p is independently an integer from 0 to 4. * indicates a bonding site with other substructures in the carbonyl group-containing compound.

[0010] According to the semiconductor substrate manufacturing method, by using a resist underlayer film formation composition containing a [A] compound with good heat resistance and film homogeneity in the coating step, a resist underlayer film with excellent embedding properties and flatness can be formed, making it possible to manufacture a semiconductor substrate with a good pattern shape.

[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 flatness. The semiconductor substrate manufacturing method allows for the formation of a resist underlayer film with excellent embedding properties and flatness, 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 flatness.

[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 is a compound having at least one substructure selected from the group consisting of a substructure represented by the following formula (A1) and a substructure represented by the following formula (A2). The resist underlayer film forming composition may contain one or more [A] compounds. (In the above formulas (A1) and (A2), Ar １ and Ar ２ These are each independent aromatic rings with 3 to 20 carbon atoms. １ Each of these is independently a hydroxyl group, a nitro group, a halogen atom, or a monovalent organic group having 1 to 20 carbon atoms. １ If multiple R １ These are either identical or different from each other. In the above formula (A1), Y １ or Y ２ One of the components is a carbonyl group, and the other is a single bond, an oxygen atom, a sulfur atom, or a methylene group. n is independently 1 or 2. p is independently an integer from 0 to 4. * indicates a bonding site with other substructures in the carbonyl group-containing compound.

[0018] In the above formulas (A1) and (A2), Ar １ and Ar ２Examples of aromatic rings having 3 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 heterocyclic rings having 3 to 20 carbon atoms such as triazole rings, imidazole rings, furan rings, pyrrole rings, thiophene rings, phosphole rings, pyrazole rings, oxazole rings, isoxazole rings, thiazole rings, pyridine rings, pyrimidine rings, pyridazine rings, triazine rings, indole rings, benzimidazole rings, benzofuran rings, quinoline rings, and carbazole 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, a fluorene ring, and a quinoline ring, and more preferably a benzene ring, a naphthalene ring, a pyrene ring, or a fluorene ring. In particular, in the above formula (A1), Ar １ or Ar ２ Preferably, one of the rings is a benzene ring and the other is a naphthalene ring or a perylene ring. In the above formula (A2), Ar １ and Ar ２ Preferably, these are a benzene ring, a naphthalene ring, a quinoline ring, or a pyrene ring.

[0019] R １ Examples of halogen atoms represented by this formula include fluorine, chlorine, bromine, and iodine.

[0020] R １ 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] Examples of divalent heteroatom-containing linking groups include -CO-, -CS-, -NR'-, -O-, -S-, and -SO ２ - and combinations thereof are examples. R' is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms.

[0027] Examples of monovalent heteroatom-containing substituents include hydroxyl groups, sulfanyl groups, cyano groups, nitro groups, amino groups, and halogen atoms.

[0028] R １ Preferably, the group is a monovalent alkyl group having 1 to 20 carbon atoms, a monovalent alkoxy group having 1 to 20 carbon atoms, a monovalent alkynyloxy group having 2 to 20 carbon atoms, a monovalent aralkyl group having 7 to 20 carbon atoms, a monovalent aralkyloxy group having 7 to 20 carbon atoms, a hydroxyl group, or a combination thereof. More preferably, the group is a monovalent alkyl group having 1 to 10 carbon atoms, a monovalent alkoxy group having 1 to 5 carbon atoms, a monovalent alkynyloxy group having 2 to 6 carbon atoms, a monovalent aralkyl group having 7 to 12 carbon atoms, a monovalent aralkyloxy group having 7 to 10 carbon atoms, a hydroxyl group, or a combination thereof. Even more preferably, the group is a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a methoxy group, an ethoxy group, a propoxy group, a propargyloxy group, a benzyl group, a benzyloxy group, or a combination thereof.

[0029] Y １ or Y ２ Preferably, one of the bonds is a carbonyl group and the other is a single bond.

[0030] p is preferably an integer between 0 and 3, more preferably an integer between 0 and 2, and even more preferably 0 or 1.

[0031] Other substructures in the above carbonyl group-containing compounds represented by * also include hydrogen atoms.

[0032] [A] The compound is preferably a polymer having a repeating unit represented by the following formula (A1-1), a polymer having a repeating unit represented by the following formula (A1-2), a polymer having a repeating unit represented by the following formula (A1-3), a polymer having a repeating unit represented by the following formula (A1-4), a compound represented by the following formula (A1-5), a compound represented by the following formula (A1-6), or a polymer having a repeating unit represented by the following formula (A2-1). (In the above formulas (A1-1) to (A1-6) and (A2-1), Ar １ Ar ２ , R １ , Y １ , Y ２And p are equivalent to formulas (A1) and (A2) above. u is an integer from 1 to 4. v1 and v2 are independently integers from 0 to 2, where v1 + v2 is 1 or greater. Z are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. W ａ is a divalent organic group having 1 to 40 carbon atoms. When u is 1, 3, or 4, W ｂ This is an organic group with 1 to 40 carbon atoms and a u-valent charge. When u is 2, W ｂ (This refers to a single bond, a divalent heteroatom-containing linking group, or a divalent organic group having 1 to 40 carbon atoms.)

[0033] In the above formulas (A1-1) to (A1-2) and (A2-1), the monovalent organic group having 1 to 20 carbon atoms represented by Z is R in the above formulas (A1) and (A2). １ A monovalent organic group having 1 to 20 carbon atoms represented by the formula (A1) above can be suitably used. Z is preferably a monovalent group containing a substituted or unsubstituted aromatic ring having 3 to 20 carbon atoms, or an alkyl group having 1 to 10 carbon atoms. As a monovalent group containing an aromatic ring having 3 to 20 carbon atoms represented by Z, the Ar of the above formulas (A1) and (A2) above can be used. １ and Ar ２ A group obtained by removing one hydrogen atom from an aromatic ring having 3 to 20 carbon atoms, as shown in [reference], can be suitably adopted. In particular, Z is preferably a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, an alkyl group having 1 to 8 carbon atoms, or a group in which the hydrogen atoms of these groups are substituted with substituents, and more preferably a phenyl group, naphthyl group, pyrenyl group, biphenyl group, pentyl group, hexyl group, or a group in which the hydrogen atoms of these groups are substituted with substituents.

[0034] If the aromatic ring in Z has substituents, examples of substituents include halogen atoms such as fluorine, chlorine, bromine, and iodine; 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.

[0035] In the above formulas (A1-3) to (A1-4), W ａ As a divalent organic group having 1 to 40 carbon atoms represented by the above formula (A1) and formula (A2), R １ A monovalent organic group with 1 to 20 carbon atoms represented by can be preferably adopted, which is an extended group with 40 carbon atoms, with one hydrogen atom removed. ａ Preferably, it is a substituted or unsubstituted divalent hydrocarbon group having 1 to 40 carbon atoms, or a group having a divalent heteroatom-containing linking group between the carbon atoms of the hydrocarbon group. ａ The divalent hydrocarbon group having 1 to 40 carbon atoms in the above formula (A1) and formula (A2) is R １ In particular, a group obtained by extending the monovalent hydrocarbon group having 1 to 20 carbon atoms shown above up to 40 carbon atoms, and then removing one hydrogen atom from that group, can be suitably adopted. ａ Each of these groups is preferably independently a group obtained by removing one hydrogen atom from a monovalent chain hydrocarbon having 1 to 40 carbon atoms, a group obtained by removing one hydrogen atom from a monovalent aromatic hydrocarbon group having 6 to 40 carbon atoms, or a combination thereof; more preferably a group obtained by removing one hydrogen atom from a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a group obtained by removing one hydrogen atom from a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, or a combination thereof; and even more preferably a propanediyl group, butanediyl group, pentanediyl group, hexanediyl group, benzenediyl group, naphthalenediyl group, fluororangeyl group, or a combination thereof.

[0036] In the above formula (A1-5), when u is 1, 3, or 4, W ｂ As for the u-valent organic group having 1 to 40 carbon atoms represented by the above formula (A1) and formula (A2), R １ A group obtained by extending the monovalent organic group with 1 to 20 carbon atoms represented by the formula up to 40 carbon atoms, and then removing u-1 hydrogen atoms from that group, can be suitably adopted. ｂ Preferably, it is a substituted or unsubstituted u-valent hydrocarbon group having 1 to 40 carbon atoms, or a group having the above-mentioned divalent heteroatom-containing linking group between the carbon atoms of the hydrocarbon group. ｂIn this, the u-valent hydrocarbon group having 1 to 40 carbon atoms is R in the above formulas (A1) and (A2). １ A suitable group can be obtained by removing u hydrogen atoms from a hydrocarbon corresponding to a group that extends the monovalent hydrocarbon group having 1 to 20 carbon atoms shown above up to 40 carbon atoms. The hydrocarbon group having 1 to 40 carbon atoms is preferably a hydrocarbon corresponding to a monovalent chain hydrocarbon having 1 to 40 carbon atoms, an aromatic hydrocarbon corresponding to a monovalent aromatic hydrocarbon group having 6 to 40 carbon atoms, or a combination thereof. More preferably, a chain saturated hydrocarbon corresponding to a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon corresponding to a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, or a combination thereof is preferred. Even more preferably, methane, ethane, propane, butane, pentane, hexane, heptane, octane, benzene, naphthalene, fluorene, or a combination thereof is preferred.

[0037] When u is 2, W ｂ As a divalent organic group having 1 to 40 carbon atoms, the case where u is 1, 3, or 4 is W ｂ A divalent organic group with 1 to 40 carbon atoms, represented by [formula], can be suitably adopted.

[0038] In the above formula (A1-5), u is preferably an integer between 1 and 3, and more preferably 1 or 2.

[0039] In the above formula (A1-6), v1 and v2 are preferably 0 or 1, and more preferably both are 1.

[0040] In the above formulas (A2) and (A2-1), p is an integer from 1 to 4, and R １ Preferably, each of these is independently a hydroxyl group or a monovalent organic group having 1 to 20 carbon atoms bonded to the aromatic ring via an ether bond. Preferred monovalent organic groups having 1 to 20 carbon atoms bonded to the aromatic ring via an ether bond include a monovalent alkoxy group having 1 to 20 carbon atoms, a monovalent alkynyloxy group having 2 to 20 carbon atoms, or a monovalent aralkyloxy group having 7 to 20 carbon atoms, more preferably a monovalent alkynyloxy group having 2 to 10 carbon atoms, and even more preferably a propargyloxy group.

[0041] Specific examples of polymers having repeating units represented by the above formula (A1-1) include, but are not limited to, polymers having repeating units represented by the following formula.

[0042]

[0043]

[0044] Specific examples of polymers having repeating units represented by the above formula (A1-2) include, but are not limited to, polymers having repeating units represented by the following formula.

[0045]

[0046] Specific examples of polymers having repeating units represented by the above formula (A1-3) include, but are not limited to, polymers having repeating units represented by the following formula.

[0047]

[0048] Specific examples of polymers having repeating units represented by the above formula (A1-4) include, but are not limited to, polymers having repeating units represented by the following formula.

[0049]

[0050] Specific examples of compounds represented by the above formulas (A1-5) include, but are not limited to, compounds represented by the following formulas.

[0051]

[0052]

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

[0054]

[0055] Specific examples of polymers having repeating units represented by the above formula (A2-1) include, but are not limited to, polymers having repeating units represented by the following formula.

[0056]

[0057]

[0058] [A] The molecular weight of compound [A] is preferably 500 or more, regardless of whether compound [A] is a polymer or a low molecular weight compound without repeating units. When compound [A] is a polymer, the lower limit of the molecular weight of compound [A] is preferably 1200, and more preferably 1600. The upper limit of the molecular weight is preferably 10000, and more preferably 8000. When compound [A] is a low molecular weight compound, the lower limit of the molecular weight of compound [A] is more preferably 550, and even more preferably 600. The upper limit of the molecular weight is preferably 1200, and more preferably 800. 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.

[0059] The content of compound [A] in the components other than the solvent in the above resist underlayer film forming composition is preferably 1% 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.

[0060] <Methods for producing [A] compounds> Although there are no particular limitations on the methods for producing [A] compounds, typical methods include: (1) an acid-catalyzed addition-condensation reaction between a carbonyl group-containing aromatic compound (hereinafter also referred to as "[a] compound") and an aldehyde (hereinafter also referred to as "[b] compound"); (2) an addition reaction of a halogenated compound (hereinafter also referred to as "[c1] compound") to a carbonyl group-containing aromatic compound and a subsequent oxidation reaction; and (3) a cross-coupling reaction between a halogenated carbonyl group-containing aromatic compound and an organometallic compound (hereinafter also referred to as "[c2] compound") in the presence of a transition metal catalyst.

[0061] ([a] compound) A [a] compound is a compound represented by the following formula (a1), formula (a2), or formula (a3) ​​(hereinafter referred to as "[a1] compound," etc.).

[0062] (In formulas (a1) to (a3), Ar １ Ar ２ , R １ , Y １ , Y ２ And p are equivalent to formulas (A1) and (A2) above. X is independently a halogen atom. g is independently an integer between 0 and 2. However, in the case of reaction (3) above, the sum of g in one formula is 2 or more.

[0063] In the above formulas (a1) to (a3), the halogen atom represented by X is preferably a bromine atom.

[0064] [a1] Specific examples of compounds include, but are not limited to, compounds represented by the following formula.

[0065]

[0066] [a2] Specific examples of compounds include, but are not limited to, compounds represented by the following formula.

[0067]

[0068] [a3] Specific examples of compounds include, but are not limited to, compounds represented by the following formula.

[0069]

[0070] ([b] compound) The [b] compound is a compound represented by the following formula (b). (In equation (b), Z is equivalent to equations (A1-1), (A1-2), and (A2-1) above.)

[0071] [b] Specific examples of compounds include, but are not limited to, compounds represented by the following formula.

[0072]

[0073] ([c1] compound) The [c1] compound is not particularly limited, but it is preferably a compound represented by the following formula (c1).

[0074] (In the above formula (c1), W １ X is an organic group with 1 to 40 carbon atoms and a u-valent charge. ｃ is a halogen atom. u is equivalent to the above formula (A1-5). If u is 2 or more, multiple X ｃ They are either identical or different from one another.

[0075] In the above formula (c1), W １ As an organic group with 1 to 40 carbon atoms represented by the above formula (A1-5), W ｂ Organic groups with 1 to 40 carbon atoms represented by the formula can be suitably used.

[0076] X ｃ The halogen atom represented is preferably a bromine atom.

[0077] [c1] Specific examples of the halogenated compounds that give the compound include, but are not limited to, compounds represented by the following formula.

[0078]

[0079] ([c2] compound) As the [c2] compound, known organometallic compounds used in cross-coupling reactions can be used. Examples of metals in the organometallic compound include boron, zinc, tin, silicon, etc., with boron being preferred. The [c2] compound is preferably a compound represented by the following formula (c2).

[0080] (In the above formula (c2), W ２ R is a divalent organic group having 1 to 40 carbon atoms. ｃ and R ｃｃ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, or R ｃ and R ｃｃ They combine with each other and form a ring structure with the boron atoms to which they bond.

[0081] In the above formula (c2), W ２ As a divalent organic group having 1 to 40 carbon atoms represented by the above formulas (A1-3) to (A1-4), W ａ Divalent organic groups having 1 to 40 carbon atoms, represented by [formula], can be suitably used.

[0082] R ｃ and R ｃｃ As a monovalent organic group having 1 to 20 carbon atoms represented by the above formula (A1) and formula (A2), R １ A monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably used.

[0083] R ｃ and R ｃｃ Examples of ring structures formed by this include ring structures in which the two oxygen atoms of -O-B-O- in the formula and the alkanediyl group are bonded at both ends, and structures in which an aromatic ring is fused to the two carbon atoms of the alkanediyl group. Examples of alkanediyl groups include alkanediyl groups having 1 to 5 carbon atoms, such as methanediyl groups, ethanediyl groups, and propanediyl groups. Examples of aromatic rings that condense with the above alkanediyl groups include Ar in formulas (A1) and (A2) above. １ and Ar ２ Aromatic rings with 3 to 20 carbon atoms, represented by [the formula shown], can be suitably used.

[0084] R ｃ and R ｃｃ Preferably, both are hydrogen atoms.

[0085] [c2] Specific examples of compounds include, but are not limited to, compounds represented by the following formula.

[0086]

[0087] In reaction (1) above, the acid addition condensation of compound [a] and compound [b] may be carried out according to a known method. Preferably, it can be carried out in a reaction solvent under an inert gas atmosphere such as a nitrogen gas atmosphere. The reaction temperature is preferably 80°C to 160°C, and may be set to a temperature at which reflux of the solvent occurs. The reaction time is preferably 1 hour to 36 hours. An acid catalyst may be added during the reaction. The acid catalyst is not particularly limited, and known inorganic acids and organic acids can be used. 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.

[0088] The above reaction (2) can also be carried out according to known methods. Typically, a Grignard reagent is prepared by reacting magnesium with compound [c1] in a solvent. Lithium, zinc, etc. may be used instead of magnesium. Subsequently, compound [a] is added to the prepared solution and the reaction is carried out at 20°C to 80°C for 1 to 10 hours. 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.

[0089] Furthermore, the benzanthrone structure of compound [a] undergoes 1,4-addition upon reaction with a Grignard reagent, but is reverted to a fused ring structure upon oxidation. Oxidation proceeds sufficiently with oxygen in the air, but an oxidizing agent may be used if necessary.

[0090] (In the scheme, R is a monovalent organic group, and [O] is oxygen or an oxidizing agent.)

[0091] The above reaction (3) can also be carried out according to known methods. Typically, this method involves reacting a halogenated [a] compound and a [c2] compound at 50°C to 150°C for 2 to 15 hours in the presence of a transition metal catalyst. Palladium catalysts such as palladium acetate are preferred as the transition metal catalyst. After the reaction, the [A] compound can be obtained by separation, purification, drying, etc. The [B] solvent described later can be suitably used as the reaction solvent.

[0092] <[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.

[0093] [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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] Examples of ketone solvents include linear ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, and cyclic ketone solvents such as cyclohexanone.

[0098] 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.

[0099] 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.

[0100] [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.

[0101] 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.

[0102] [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 acid generators, crosslinking agents, surfactants, base generators, defoaming agents, etc. 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.). These compounds may be used individually or in combination of two or more. As 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.

[0103] [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.

[0104] 《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").

[0105] 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").

[0106] 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").

[0107] The following describes each step in the manufacturing method of the semiconductor substrate, including the optional steps of the heating step and the silicon-containing film formation step.

[0108] [Coating Process] In this process, the resist underlayer film formation composition is coated onto the substrate either directly or indirectly. In this process, the resist underlayer film formation composition described above is used.

[0109] 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 thereafter, and the resist underlayer film is formed by the volatilization of solvent [B].

[0110] 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.

[0111] 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.

[0112] 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.

[0113] [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.

[0114] The heating of the coating film may be carried out in an air atmosphere or in a nitrogen atmosphere. As the lower limit of the heating temperature, 200 °C is preferable, and 240 °C is more preferable. As the upper limit of the heating temperature, 600 °C is preferable, and 500 °C is more preferable. As the lower limit of the time in heating, 15 seconds is preferable, and 30 seconds is more preferable. As the upper limit of the time, 1,200 seconds is preferable, and 600 seconds is more preferable.

[0115] In addition, after the coating step, the resist underlayer film may be exposed. After the coating step, the resist underlayer film may be exposed to plasma. After the coating step, ion implantation may be performed on the resist underlayer film. When the resist underlayer film is exposed, the etching resistance of the resist underlayer film is improved. When the resist underlayer film is exposed to plasma, the etching resistance of the resist underlayer film is improved. When ion implantation is performed on the resist underlayer film, the etching resistance of the resist underlayer film is improved.

[0116] 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, γ-rays; and particle beams such as electron beams, molecular beams, and ion beams.

[0117] As a method for exposing the resist underlayer film to plasma, for example, a direct method by placing the substrate in each gas atmosphere and performing plasma discharge can be mentioned. As the conditions for plasma exposure, usually the gas flow rate is 50 cc / min or more and 100 cc / min or less, and the supply power is 100 W or more and 1,500 W or less.

[0118] As the lower limit of the time for plasma exposure, 10 seconds is preferable, 30 seconds is more preferable, and 1 minute is even more preferable. As the upper limit of the time, 10 minutes is preferable, 5 minutes is more preferable, and 2 minutes is even more preferable.

[0119] Plasma is generated, for example, in an atmosphere of a mixed gas of H ２ gas and Ar gas. Also, in addition to H ２ gas and Ar gas, a carbon-containing gas such as CF ４ gas or CH ４ gas may be introduced. Incidentally, H ２Instead of either or both of the 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 which may be introduced.

[0120] Ion implantation into the resist underlayer film injects a dopant into the resist underlayer film. The dopant can be selected from the group consisting of boron, carbon, nitrogen, phosphorus, arsenic, aluminum, and tungsten. The implantation energy used to apply a voltage to the dopant ranges from about 0.5 keV to 60 keV depending on the type of dopant used and the desired depth of implantation.

[0121] As the lower limit of the average thickness of the formed resist underlayer film, 30 nm is preferable, 50 nm is more preferable, and 80 nm is even more preferable. As the upper limit of the average thickness, 3,000 nm is preferable, 2,000 nm is more preferable, and 500 nm is even more preferable. The method for measuring the average thickness is as described in the examples.

[0122] [Silicon-containing film formation step] In this step, a silicon-containing film is formed directly or indirectly on the resist underlayer film formed by the coating step or the heating step. Examples of the case where a silicon-containing film is formed indirectly on the resist underlayer film include the case where 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 having a contact angle with water different from that of the resist underlayer film.

[0123] 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).

[0124] 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.

[0125] The lower limit of the temperature when heating the coating film is preferably 90°C, more preferably 150°C, and even more preferably 200°C. The upper limit of the above temperature is preferably 550°C, more preferably 450°C, and even more preferably 300°C.

[0126] 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.

[0127] [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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] After development with the above-mentioned developer, the resist pattern is formed by washing and drying.

[0134] [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.

[0135] 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 Cl２ , 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 ２ Examples 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.

[0136] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0137] [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).

[0138] [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.

[0139] <[A] Starting materials used in the synthesis of compound [A]> For the synthesis of compound [A], the following compounds (a-1) to (a-10) were used as [a] compounds, the following compounds (b-1) to (b-9) were used as [b] compounds, and the following compounds (c-1) to (c-9) were used as [c] compounds ([c1] compound or [c2] compound).

[0140]

[0141]

[0142]

[0143] <Synthesis of Compound [A]> Compounds (A-1) to (A-29), represented by the following formulas, were synthesized according to the procedure shown below.

[0144]

[0145]

[0146]

[0147]

[0148]

[0149]

[0150]

[0151] [Example 1-1] (Synthesis of polymer (A-1)) In a reaction vessel, under a nitrogen atmosphere, 20.0 g of compound (a-1), 2.67 g of paraformaldehyde (b-1), and 120 g of 1-propoxy-2-propanol were added and heated to 80°C. Then, 20.0 g of methanesulfonic acid was slowly added dropwise, and the mixture was reacted under reflux for 12 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 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 hexane / diisopropyl ether = 5 / 5 (v / v) solution to obtain a precipitate. The precipitate was collected by suction filtration and washed several times with 200 g of hexane. Then, polymer (A-1) was obtained by drying in a vacuum dryer at 60°C for 12 hours. The Mw of (A-1) was 3500.

[0152] [Examples 1-2 to 1-9, 1-21 to 1-22, 1-24, 1-26 to 1-29] (Synthesis of polymers (A-2) to (A-9), (A-21) to (A-22), (A-24), (A-26) to (A-29)) Polymers (A-2) to (A-9), (A-21) to (A-22), (A-24), (A-26) to (A-29) were obtained as products under the same reaction conditions as in Example 1-1, except that the starting compounds shown in Table 1 were used.

[0153] [Example 1-10] (Synthesis of polymer (A-10)) In a reaction vessel, under a nitrogen atmosphere, 20.0 g of compound (a-2), 1.27 g of paraformaldehyde (b-1), 100 g of mesitylene, and 60 g of 1-propoxy-2-propanol were added and heated to 80°C. Then, 16.0 g of methanesulfonic acid was slowly added dropwise, and the mixture was reacted under reflux for 12 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% aqueous oxalic acid. After separating the aqueous phase, the obtained organic phase was washed several times with water. Then, it was concentrated using 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. Subsequently, polymer (A-10) was obtained by drying in a vacuum dryer at 60°C for 12 hours. The Mw of (A-1) was 6400.

[0154] [Example 1-11] (Synthesis of polymer (A-11)) Polymer (A-11) was obtained as the product under the same reaction conditions as in Example 1-10, except that compound (a-3) was used instead of compound (a-2).

[0155] [Example 1-12] (Synthesis of compound (A-12)) In a reaction vessel, under a nitrogen atmosphere, 2.32 g of magnesium and 40 g of tetrahydrofuran were added. 14.9 g of compound (c-1), which had been pre-dissolved in 40 g of tetrahydrofuran, was added dropwise while maintaining the temperature below 40°C, and the mixture was reacted at 40°C for 1 hour. The resulting solution was cooled to room temperature, and 20.0 g of compound (a-1), which had been dissolved in 120 g of tetrahydrofuran, was slowly added dropwise, and the mixture was reacted at 60°C for 4 hours. After adding 400 g of ultrapure water to stop the reaction, the aerosol phase was extracted with 400 g of chloroform. The aerosol phase obtained by extraction was washed with 500 g of 1% oxalic acid solution, and the resulting organic phase was washed several times with water. The resulting aerosol phase was vigorously stirred under air at 40°C for 12 hours, then concentrated in an evaporator, and the residue was added dropwise to 400 g of solution to obtain a precipitate. The precipitate was collected by suction filtration and washed several times with 200 g of methanol. Subsequently, compound (A-12) was obtained by drying in a vacuum dryer at 60°C for 12 hours. The Mw of (A-12) was 611.

[0156] [Examples 1-13 to 1-16] (Synthesis of compounds (A-13) to (A-16)) Compounds (A-13) to (A-16) were obtained as products under the same reaction conditions as in Example 1-12, except that the same starting compounds shown in Table 1 were used.

[0157] [Example 1-17] (Synthesis of compound (A-17)) In a reaction vessel, under a nitrogen atmosphere, 1.06 g of magnesium and 20 g of tetrahydrofuran were added. 21.9 g of compound (c-6), which had been pre-dissolved in 80 g of tetrahydrofuran, was added dropwise while maintaining the temperature below 40°C, and the reaction was carried out at 40°C for 1 hour. The resulting solution was cooled to room temperature, and 10.0 g of compound (a-1), which had been dissolved in 120 g of tetrahydrofuran, was slowly added dropwise, and the reaction was carried out at 60°C for 4 hours. After adding 400 g of ultrapure water to stop the reaction, the aerosol phase was extracted with 400 g of chloroform. The aerosol phase obtained by extraction was washed with 500 g of 1% oxalic acid solution, and the resulting organic phase was washed several times with water. The obtained aerosol phase was vigorously stirred under air at 40°C for 12 hours, then concentrated in an evaporator, and the residue was added dropwise to 400 g of solution to obtain a precipitate. The precipitate was collected by suction filtration and washed several times with 200 g of methanol. Subsequently, compound (A-17) was obtained by drying in a vacuum dryer at 60°C for 12 hours. The Mw of (A-17) was 653.

[0158] [Example 1-18] (Synthesis of compound (A-18)) In a reaction vessel, under a nitrogen atmosphere, 2.24 g of magnesium and 40 g of tetrahydrofuran were added. 19.1 g of compound (c-7), which had been pre-dissolved in 40 g of tetrahydrofuran, was added dropwise while maintaining the temperature below 40°C, and the reaction was carried out at 40°C for 1 hour. The resulting solution was cooled to room temperature, and 20.0 g of compound (a-2), which had been dissolved in 120 g of tetrahydrofuran, was slowly added dropwise, and the reaction was carried out at 60°C for 4 hours. After adding 400 g of ultrapure water to stop the reaction, the aerosol phase was extracted with 400 g of chloroform. The aerosol phase obtained by extraction was washed with 500 g of 1% oxalic acid solution, and the resulting organic phase was washed several times with water. The obtained aerosol phase was vigorously stirred under air at 40°C for 12 hours, then concentrated in an evaporator, and the residue was added dropwise to 400 g of solution to obtain a precipitate. The precipitate was collected by suction filtration and washed several times with 200 g of methanol. Subsequently, compound (A-18) was obtained by drying in a vacuum dryer at 60°C for 12 hours. The Mw of (A-18) was 709.

[0159] [Example 1-19] (Synthesis of polymer (A-19)) Polymer (A-19) was obtained as the product under the same reaction conditions as in Example 1-18, except that the starting compound shown in Table 1 was used.

[0160] [Example 1-20] (Synthesis of polymer (A-20)) In a reaction vessel, under a nitrogen atmosphere, 20.0 g of compound (a-4), 8.54 g of compound (c-8), 14.2 g of potassium carbonate, 1.16 g of palladium(II) acetate, 1.35 g of triphenylphosphine, and 200 g of N,N-dimethylformamide were added and the mixture was reacted at 110°C for 8 hours. After the reaction was complete, the residue was filtered, and the reaction solution was transferred to a separatory funnel. 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, the mixture was concentrated using 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. Subsequently, polymer (A-20) was obtained by drying in a vacuum dryer at 60°C for 12 hours. The Mw of (A-20) was 3100.

[0161] [Example 1-23] (Synthesis of polymer (A-23)) In a reaction vessel, under a nitrogen atmosphere, 20.0 g of polymer (A-22), 27.1 g of potassium carbonate, and N,N-dimethylacetamide were added, and 23.3 g of compound (c-9) was slowly added dropwise. The reaction was carried out at 80°C for 6 hours. After the reaction was complete, the residue was filtered and the reaction solution was transferred to a separatory funnel. 500 g of methyl isobutyl ketone and 500 g of 1% oxalic acid solution were added to wash the organic phase. After separating the aqueous phase, the obtained organic phase was washed several times with water. The mixture was then concentrated using an evaporator, and the residue was added dropwise to 400 g of methanol to obtain a precipitate. The precipitate was collected by suction filtration and washed several times with 200 g of methanol. Polymer (A-23) was then obtained by drying in a vacuum dryer at 60°C for 12 hours. The Mw of (A-23) was 3900.

[0162] [Example 1-25] (Synthesis of polymer (A-25)) Polymer (A-25) was obtained as the product under the same reaction conditions as in Example 1-23, except that the starting compound shown in Table 1 was used.

[0163] [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.

[0164]

[0165]

[0166] <Preparation of composition for forming a resist underlayer film> The following describes the [A] compound, [B] solvent, [C] acid generator, [D] 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").

[0167] [[A] Compounds] A-1 to A-29: Compounds synthesized above (A-1) to (A-29)

[0168] [B Solvent] B-1: Propylene glycol monomethyl ether acetate B-2: Cyclohexanone

[0169] [C] Acid Generator: C-1: Compound represented by the following formula (C-1)

[0170] [D] Crosslinking agent: D-1: Compound represented by the following formula (D-1) D-2: Compound represented by the following formula (D-2)

[0171] [Other components] x-1: The polymer synthesized above (x-1)

[0172] [Example 2-1] [A] 3 parts by mass of (A-1) as a compound and [D] 0.3 parts by mass of (D-1) as a crosslinking agent were dissolved in 97 parts by mass of (B-1) as a solvent. The resulting solution was filtered through a polytetrafluoroethylene (PTFE) membrane filter with a pore size of 0.45 μm to prepare composition (J-1).

[0173] [Examples 2-2 to 2-36 and Comparative Example 2-1] Compositions (J-2) to (J-36) and (CJ-1) were prepared in the same manner as in Example 2-1, except that the components used were of the types and in the amounts shown in Table 2 below. A "-" in Table 2 indicates that the corresponding component was not used.

[0174]

[0175] <Evaluation> [Examples 3-1 to 3-36 and Comparative Example 3-1] The embedding properties and flatness were evaluated using the above-prepared resist underlayer film formation compositions by the following method. The evaluation results are also shown in Table 3 below.

[0176] [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.

[0177] [Flatness] The above-prepared composition was coated onto a silicon substrate 1 on which a trench pattern with a depth of 150 nm and a width of 10 μm was formed, using a spin coater (CLEAN TRACK ACT12 from Tokyo Electron Ltd.) by rotary coating, as shown in Figure 1. Next, a resist underlayer film 2 with an average thickness of 200 nm in the non-trenched areas was formed by heating at 250°C for 60 seconds in an air atmosphere and then cooling at 23°C for 60 seconds. Then, a silicon substrate with a resist underlayer film was obtained by heating at 350°C for 60 seconds in an air atmosphere and then cooling at 23°C for 60 seconds. The cross-sectional shape of the silicon substrate with the resist underlayer film described above was observed using a scanning electron microscope (Hitachi High-Technologies Corporation's "S-4800"). The difference (ΔFT) between the height of the central portion b of the trench pattern in the resist underlayer film 2 and the height of the non-trenched portion a located 5 μm from the edge of the trench pattern was used as an indicator of flatness. Flatness was evaluated as follows: "A" (good) if the ΔFT was less than 20 nm, "B" (fairly good) if the ΔFT was between 20 nm and 30 nm, and "C" (poor) if the ΔFT was 30 nm or more. Note that the height difference shown in Figure 1 is exaggerated compared to the actual difference.

[0178]

[0179] As can be seen from the results in Table 3, the compositions of the examples and the resist underlayer films formed from these compositions exhibited superior embedding and flatness compared to the comparative examples.

[0180] The resist underlayer film formation composition of the present invention makes it possible to form a resist underlayer film with excellent embedding properties and flatness. 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 embed the substrate pattern, but also has excellent flatness of the film after embedding. Therefore, these can be suitably used in the manufacture of semiconductor devices, for which further miniaturization is expected to progress in the future.

[0181] 1. Silicon substrate 2. Resist underlayer

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 at least one substructure selected from the group consisting of a substructure represented by the following formula (A1) and a substructure represented by the following formula (A2). (In the above formulas (A1) and (A2), Ar １ and Ar ２ These are each independent aromatic rings with 3 to 20 carbon atoms. １ Each of these is independently a hydroxyl group, a nitro group, a halogen atom, or a monovalent organic group having 1 to 20 carbon atoms. １ If multiple R １ These are either identical or different from each other. In the above formula (A1), Y １ or Y ２ One of the components is a carbonyl group, and the other is a single bond, an oxygen atom, a sulfur atom, or a methylene group. n is independently 1 or 2. p is independently an integer from 0 to 4. * indicates a bonding site with other substructures in the carbonyl group-containing compound.

2. The carbonyl group-containing compound is a polymer having a repeating unit represented by the following formula (A1-1), a polymer having a repeating unit represented by the following formula (A1-2), a polymer having a repeating unit represented by the following formula (A1-3), a polymer having a repeating unit represented by the following formula (A1-4), a compound represented by the following formula (A1-5), a compound represented by the following formula (A1-6), or a polymer having a repeating unit represented by the following formula (A2-1). The composition for forming a resist lower layer film according to claim 1. (In the above formulas (A1-1) to (A1-6) and formula (A2-1), Ar １ , Ar ２ , R １ , Y １ , Y ２ and p are as defined in the above formulas (A1) and (A2). u is an integer of 1 to 4. v1 and v2 are each independently an integer of 0 to 2. However, v1 + v2 is 1 or more. Z is each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. W ａ is a divalent organic group having 1 to 40 carbon atoms. When u is 1, 3 or 4, W ｂ is a u-valent organic group having 1 to 40 carbon atoms. When u is 2, W ｂ is a single bond, a divalent heteroatom-containing linking group, or a divalent organic group having 1 to 40 carbon atoms.) 3. In the above formulas (A2) and (A2-1), p is an integer from 1 to 4, and R １ The resist underlayer film forming composition according to claim 1 or 2, wherein each is independently a hydroxyl group or a monovalent organic group having 1 to 20 carbon atoms bonded to the aromatic ring via an ether bond.

4. 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 at least one substructure selected from the group consisting of a substructure represented by the following formula (A1) and a substructure represented by the following formula (A2). (In the above formulas (A1) and (A2), Ar １ and Ar ２ These are each independent aromatic rings with 3 to 20 carbon atoms. １ Each of these is independently a hydroxyl group, a nitro group, a halogen atom, or a monovalent organic group having 1 to 20 carbon atoms. １ If multiple R １ These are either identical or different from each other. In the above formula (A1), Y １ or Y ２ One of the components is a carbonyl group, and the other is a single bond, an oxygen atom, a sulfur atom, or a methylene group. n is independently 1 or 2. p is independently an integer from 0 to 4. * indicates a bonding site with other substructures in the carbonyl group-containing compound.

5. The method for producing a semiconductor substrate according to claim 4, wherein the carbonyl group-containing compound is a polymer having a repeating unit represented by the following formula (A1-1), a polymer having a repeating unit represented by the following formula (A1-2), a polymer having a repeating unit represented by the following formula (A1-3), a polymer having a repeating unit represented by the following formula (A1-4), a compound represented by the following formula (A1-5), a compound represented by the following formula (A1-6), or a polymer having a repeating unit represented by the following formula (A2-1). (In the above formulas (A1-1) to (A1-6) and (A2-1), Ar １ Ar ２ , R １ , Y １ , Y ２ And p are equivalent to formulas (A1) and (A2) above. u is an integer from 1 to 4. v1 and v2 are independently integers from 0 to 2, where v1 + v2 is 1 or greater. Z are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. W ａ is a divalent organic group having 1 to 40 carbon atoms. When u is 1, 3, or 4, W ｂ This is an organic group with 1 to 40 carbon atoms and a u-valent charge. When u is 2, W ｂ (This refers to a single bond, a divalent heteroatom-containing linking group, or a divalent organic group having 1 to 40 carbon atoms.) 6. In the above formulas (A2) and (A2-1), p is an integer from 1 to 4, and R １ The method for producing a semiconductor substrate according to claim 4 or 5, wherein each is independently a hydroxyl group or a monovalent organic group having 1 to 20 carbon atoms bonded to the aromatic ring via an ether bond.

7. The method for manufacturing a semiconductor substrate according to claim 4 or claim 5, further comprising the step of forming a silicon-containing film directly or indirectly on the resist underlayer film before forming the resist pattern.

Images