Resist underlayer film forming composition

Abstract

The present invention provides a resist underlayer film forming composition which makes it possible to suppress a deterioration of line width roughness (LWR) during the formation of a resist pattern without causing intermixture with a resist film formed on a resist underlayer film. Provided is a resist underlayer film forming composition comprising: (A) a phenol-based antioxidant which has a carbon number of seven or more and in which at least one of the carbon atoms at the ortho position and the para position of a phenolic hydroxy group on an aryl ring has a hydrogen atom that can be substituted; (B) a crosslinking agent-reactive polymer; (C) a crosslinking agent; (D) a curing catalyst; and (E) a solvent. Also provided are a resist underlayer film which is a cured product of a coating film made of the resist underlayer film forming composition and a method for producing a semiconductor device in which the resist underlayer film forming composition is used.

Description

Resist underlayer film-forming composition

[0001] The present invention relates to a composition used in a lithography process in semiconductor manufacturing, a method for manufacturing a substrate having a resist pattern using the resist underlayer film, and a method for manufacturing a semiconductor device.

[0002] In the manufacture of semiconductor devices, microfabrication by lithography using a resist composition has traditionally been performed. This microfabrication process involves forming a thin film of a photoresist composition on a semiconductor substrate, such as a silicon wafer, irradiating the substrate with active light such as ultraviolet light through a mask pattern bearing a device pattern, developing the film, and etching the substrate using the resulting photoresist pattern as a protective film, thereby forming fine irregularities on the substrate surface corresponding to the pattern. In recent years, the integration density of semiconductor devices has increased, and in addition to the conventionally used i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), and ArF excimer laser (wavelength 193 nm), the practical use of EUV light (extreme ultraviolet light, wavelength 13.5 nm) or EB (electron beam) is being considered for cutting-edge microfabrication. As a result, poor resist pattern formation due to influences from the semiconductor substrate and the like has become a major problem. To address this issue, methods of providing a resist underlayer film between the resist and the semiconductor substrate have been widely investigated.

[0003] The resist underlayer film is required to have the following characteristics: it must not intermix with the resist film formed on top of it (it must be insoluble in a resist solvent).It is also required to suppress deterioration of LWR (Line Width Roughness) during resist pattern formation, to form a resist pattern with a good rectangular shape, and to improve resist sensitivity (see Patent Documents 1 to 4).

[0004] International Publication No. 2020 / 071361 International Publication No. 2016 / 063805 International Publication No. 2013 / 141015 International Publication No. 2015 / 163195

[0005] An object of the present invention is to provide a novel composition for forming a resist underlayer film having the above-mentioned required properties, a resist underlayer film obtainable from the resist underlayer film-forming composition, a laminate having the resist underlayer film and a substrate, and a method for producing a semiconductor substrate including the laminate.

[0006] The present invention encompasses the following.

[0007] [1] A resist underlayer film-forming composition comprising: (A) a phenolic antioxidant having 7 or more carbon atoms, wherein at least one of the carbon atoms at the ortho-position or the para-position of a phenolic hydroxy group on an aryl ring has a substitutable hydrogen atom; (B) a crosslinker-reactive polymer; (C) a crosslinker; (D) a curing catalyst; and (E) a solvent.

[0008] [2] The phenolic antioxidant (A) is represented by the following formulas (I) to (III): [In formulas (1) to (III), each R independently represents an alkyl group of 1 to 10 carbon atoms which may have a substituent or a halogeno group, each Y independently represents a hydrogen atom, a hydroxy group, an alkoxy group of 1 to 10 carbon atoms, an alkyl group of 1 to 10 carbon atoms which may have a substituent, or a halogeno group, provided that when adjacent R and Y, or two adjacent Ys, are both alkyl groups which may have a substituent, they may be bonded to each other to form a ring; when one Y is a hydroxy group, the other Y on the same benzene ring represents a hydrogen atom, an alkoxy group of 1 to 10 carbon atoms, an alkyl group of 1 to 10 carbon atoms which may have a substituent, or a halogeno group, L represents an (n1+n2+n3+n4n+n5)-valent linking group that links carbon atoms on the (n1+n2+n3+n4+n5) benzene rings that constitute each phenol ring; n1, n2, n3, n4, and n5 each represent an integer of 0 or greater, and the sum of n1, n2, n3, n4, and n5 is 2 or greater.

[0009] [3] Formula (I) is the following formula (I-1) or (I-2): [The definitions of R and Y in formulas (I-1) and (I-2) are the same as in formula (I)].

[0010] [4] The resist underlayer film forming composition according to the above [1] or [2], wherein the crosslinking agent-reactive polymer (B) is a cyanuric acid-based polymer, a polyester-based polymer, or an acrylic-based polymer.

[0011] [5] The resist underlayer film-forming composition according to any one of the above [1] to [4], wherein the crosslinking agent (C) is at least one selected from the group consisting of aminoplast crosslinking agents and phenoplast crosslinking agents.

[0012] [6] The resist underlayer film-forming composition according to any one of the items [1] to [5], wherein the solvent (E) contains at least one selected from the group consisting of alkylene glycol monoalkyl ethers and monocarboxylic acid esters of alkylene glycol monoalkyl ethers.

[0013] [7] A resist underlayer film, which is a cured product of a coating film comprising the resist underlayer film-forming composition according to any one of [1] to [6] above.

[0014] [8] The resist underlayer film according to claim 7, which has a contact angle with water of 55° or more.

[0015] [9] A laminate comprising a substrate and the resist underlayer film according to claim 7 or 8.

[0016]

[10] A method for manufacturing a semiconductor device, comprising: a step of forming, on a semiconductor substrate, a resist underlayer film that is a cured product of a coating film made of the resist underlayer film-forming composition according to any one of [1] to [6]; and a step of forming a resist film on the resist underlayer film.

[0017]

[11] A method for manufacturing a semiconductor device, comprising: a step of forming, on a semiconductor substrate, a resist underlayer film that is a cured product of a coating film made of the resist underlayer film-forming composition according to any one of [1] to [6] above; a step of forming a resist film on the resist underlayer film; a step of exposing the resist film; a step of developing the exposed resist film to form a resist pattern; and a step of etching the resist underlayer film through the formed resist pattern to form a patterned resist underlayer film.

[0018] The present invention can provide a new resist underlayer film that does not undergo intermixing with a resist film formed on top of it, suppresses deterioration of LWR (Line Width Roughness, line width fluctuation (roughness)) during resist pattern formation, and enables the formation of a resist pattern with a good rectangular shape.

[0019] [1] Resist underlayer film-forming composition (1-1) A resist underlayer film-forming composition according to one embodiment of the present invention comprises: (A) a phenolic antioxidant having 7 or more carbon atoms, wherein at least one of the carbon atoms at the ortho- or para-position to the phenolic hydroxy group on the aryl ring has a substitutable hydrogen atom; (B) a crosslinker-reactive polymer; (C) a crosslinker; (D) a curing catalyst; and (E) a solvent.

[0020] (1-2) Phenol-Based Antioxidant (A) (1-2-1) The phenol-based antioxidant used in the resist underlayer film-forming composition of one embodiment of the present invention is an antioxidant having 7 or more carbon atoms, and in which at least one of the carbon atoms at the ortho- or para-position to the phenolic hydroxy group on the aryl ring has a substitutable hydrogen atom.

[0021] Examples of the aryl ring include a benzene ring, a naphthalene ring, an acenaphthylene ring, an anthracene ring, and a phenanthrene ring, with a benzene ring being preferred.

[0022] A phenolic hydroxy group refers to a hydroxy group on a benzene ring (e.g., any benzene ring constituting a naphthalene ring) that constitutes all or at least a part of an aryl ring, and at least one of the carbon atoms at the ortho or para position of the hydroxy group has a substitutable hydrogen atom. The presence of such a hydrogen atom allows the phenolic antioxidant to react with the crosslinker and become part of the resin formed after crosslinking. This reduces loss of the phenolic antioxidant during the cleaning step in the manufacturing process of semiconductor devices, and prolongs its antioxidant effect.

[0023] The phenolic antioxidant has 7 or more carbon atoms, preferably 10 or more, more preferably 11 or more, and even more preferably 14 or more. The phenolic antioxidant also has 50 or less carbon atoms, more preferably 40 or less. From the viewpoint of facilitating migration of the phenolic antioxidant to the surface and more effectively exerting the antioxidant effect when forming a cured film in a crosslinking reaction, a phenolic antioxidant with a larger carbon number and higher lipophilicity is preferred. Without being bound by theory, it is believed that this allows excess active components to be quenched before the composition unnecessarily diffuses, thereby suppressing deterioration of LWR (Line Width Roughness) during resist pattern formation.

[0024] The blending amount of the phenol-based antioxidant is preferably 0.1 to 40 mass %, more preferably 1 to 30 mass %, and even more preferably 5 to 20 mass %, relative to the solid content of the resist underlayer film composition of one embodiment of the present invention.

[0025] (1-2-2) Preferred phenolic antioxidants (A) are those represented by the following formulae (I) to (III): Examples include:

[0026] In the formulas (1) to (III), each R independently represents an alkyl group having 1 to 10 carbon atoms or a halogeno group, which may have a substituent. Preferably, R represents a tertiary alkyl group having 4 to 8 carbon atoms, and more preferably a t-butyl group.

[0027] Each Y independently represents a hydrogen atom, a hydroxy group, an alkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms which may have a substituent, or a halogeno group. When Y is an alkyl group having 1 to 10 carbon atoms which may have a substituent, it is preferably a tertiary alkyl group having 4 to 8 carbon atoms, and more preferably a t-butyl group.

[0028] However, when adjacent R and Y or two adjacent Ys are both alkyl groups which may have a substituent, they may be bonded to each other to form a ring; when one Y is a hydroxy group, the other Y on the same benzene ring represents a hydrogen atom, an alkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms which may have a substituent, or a halogeno group.

[0029] Furthermore, L represents an (n1+n2+n3+n4+n5)-valent linking group that links carbon atoms on the (n1+n2+n3+n4+n5) benzene rings that respectively constitute a phenol ring; n1, n2, n3, n4, and n5 each represent an integer of 0 or greater, and the sum of n1, n2, n3, n4, and n5 is 2 or greater, preferably 2 or 3.

[0030] L is preferably a divalent or trivalent linking group.

[0031] Examples of the divalent linking group L include -O-, -S-, and -SO ２ -, -CO-, -CONH-, -COO-, -NH-, -(CR １ R ２ ) m １ -, -(Ar)m ２ -, -CH ２ -(Ar)m ２ -CH ２ - and -(cyclo-R)-, where R １ and R ２ are the same or different and each independently represent a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms (for example, a branched or linear alkylene group having 1 to 5 carbon atoms), or an aryl group having 6 to 30 carbon atoms; m １represents an integer of 1 to 10; Ar represents an arylene group having 6 to 30 carbon atoms; m ２ represents an integer of 1 to 3, which is the number of aromatic rings bonded to each other by single bonds; cyclo-R represents a divalent alicyclic hydrocarbon group having a 5- to 8-membered ring, which may form a condensed ring with one or two benzene rings or naphthalene rings; and examples of L as a trivalent linking group include: In these formulas, R ３ each independently represents a single bond or a branched or linear alkylene group having 1 to 5 carbon atoms; Ar represents an aryltriyl group (a trivalent aromatic group, such as a triazine group) having 6 to 30 carbon atoms; cyclo-R represents a trivalent alicyclic hydrocarbon group having a 5- to 8-membered ring which may form a condensed ring with one or two benzene rings or naphthalene rings; R １ represents a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or an aryl group having 6 to 30 carbon atoms.

[0032] Formula (I) is more preferably the following formula (I-1) or (I-2): [The definitions of R and Y in formula (I-1) and formula (I-2) are the same as in formula (I)]

[0033] Furthermore, the formula (III) is more preferably the following formula (III-1): [The definitions of R and Y in formula (III-1) are the same as in formula (III). L represents an (n1+n2+n3)-valent linking group that links carbon atoms on the (n1+n2+n3) benzene rings that respectively constitute the phenol ring; n1, n2, and n3 each represent an integer of 0 or greater, and the sum of n1, n2, and n3 is 2 or greater, preferably 2 or 3.]

[0034] (1-2-2) More specifically, the phenolic antioxidant of the present invention may be exemplified by the following phenolic antioxidants, which are available from ADEKA, Tokyo Chemical Industry Co., Ltd., Kawaguchi Chemical Industry Co., Ltd., etc.

[0035]

[0036] (1-3) Crosslinker-Reactive Polymer (B) (1-3-1) The crosslinker-reactive polymer used in the resist underlayer film-forming composition of one embodiment of the present invention is a polymer that can undergo a crosslinking reaction with a crosslinker in the presence of an acid. In this embodiment, the acid is provided by a curing catalyst. The polymer may be an uncrosslinked polymer or a partially crosslinked polymer, and can form a film that does not dissolve in a photoresist solvent by reacting with the crosslinker.

[0037] At least some of the repeating structural units of the crosslinker-reactive polymer of this embodiment contain crosslinking moieties having crosslinkable functional groups for crosslinking with the crosslinker. For example, when the crosslinker is an aminoplast crosslinker or a phenoplast crosslinker, which are thought to generate cationic active species in the presence of an acid, the polymer contains structural units having crosslinkable functional groups reactive to cationic active species, such as hydroxyl groups, unsaturated hydrocarbon groups (e.g., allyl groups), and aromatic groups. Among these, hydroxyl groups are preferred as the crosslinkable functional groups.

[0038] Examples of crosslinker-reactive polymers that can be used in this embodiment include curable resins such as epoxy resins, novolak resins (including phenol-formaldehyde resins, aniline-formaldehyde resins, etc.), and unsaturated polyester resins, as well as any polymers in which a crosslinkable functional group capable of reacting with a specific crosslinker has been introduced into a specific polymer skeleton.

[0039] Suitable examples of such specific polymer skeletons include cyanuric acid polymers, polyester polymers, and acrylic polymers (polyacrylic acid, polyacrylic acid esters, polymethacrylic acid, polymethacrylic acid esters, etc.).

[0040] The polymer skeleton preferably contains a heterocyclic structure, such as furan, thiophene, pyrrole, imidazole, pyran, pyridine, pyrimidine, pyrazine, pyrrolidine, piperidine, piperazine, morpholine, indole, purine, quinoline, isoquinoline, quinuclidine, chromene, thianthrene, phenothiazine, phenoxazine, xanthene, acridine, phenazine, carbazole, triazinone, triazinedione, and triazinetrione.

[0041] The heterocyclic structure is preferably a triazineone, triazinedione or triazinetrione structure, and most preferably a triazinetrione structure.

[0042] The content of the crosslinking agent-reactive polymer is not particularly limited, but is preferably 40 to 99 mass %, more preferably 50 to 99 mass %, relative to the solid content of the resist underlayer film-forming composition of one embodiment of the present invention.

[0043] (1-3-2) Specific examples of such crosslinking agent reactive polymers include the following polymers:

[0044] (In the formula, m, n, l and numbers represent the molar ratio or the number of repeating units (any number). Usually, m, n and l are each independently an integer of 5 to 100).

[0045] (1-3-3) A suitable crosslinker-reactive polymer for use in the resist underlayer film-forming composition of one embodiment of the present invention is a reaction product (epoxy resin) of a compound containing two epoxy groups with a compound selected from the group consisting of a dicarboxylic acid-containing compound, an acid dianhydride, a compound containing two imino groups, and a compound having two hydroxy groups (WO 2022 / 039246). Ring-opening of the epoxy group forms a hydroxy group, which is a crosslinkable functional group.

[0046] Examples of compounds containing two epoxy groups include the following compounds (a) to (h) and (v) to (x). The compound containing two epoxy groups may be a compound containing two glycidyl groups.

[0047] Of the above, (a) and (x) give cyanuric acid-based polymers.

[0048] In addition, in formula (h), R ０ represents an alkylene group having 2 to 6 carbon atoms.

[0049] Furthermore, examples of compounds selected from the group consisting of dicarboxylic acid-containing compounds, acid dianhydrides, compounds containing two imino groups, and compounds having two hydroxy groups include the following compounds (i) to (u). The hydroxy groups may be phenolic hydroxy groups or non-phenolic hydroxy groups.

[0050] Of the above, (l) and (m) give cyanuric acid-based polymers.

[0051] (1-3-4) Another example of the polymer that can be used in the resist underlayer film-forming composition of one embodiment of the present invention is the polymer of the following formula (11) described in WO 2009 / 096340.

[0052] [In the above formula (11), X represents the following formula (12), formula (13), or formula (14): [In the above formulas (12), (13) and (14), R １ ~R ５ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group, or a phenyl group, and the phenyl group may be substituted with at least one group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and an alkylthio group having 1 to 6 carbon atoms; and R １ and R ２ , R ３ and R ４ may be bonded to each other to form a ring having 3 to 6 carbon atoms,１ ~A ６ each independently represents a hydrogen atom, a methyl group, or an ethyl group; １ represents a divalent group containing a disulfide bond, and n is the number of repeating unit structures and may be an integer of 5 to 100. For other information regarding this polymer, the contents of WO 2009 / 096340 are incorporated herein by reference.

[0053] (1-3-5) Still another example of the polymer used in the resist underlayer film-forming composition of an embodiment of the present invention is a polymer having a structural unit represented by the following formula (23), which is described in WO 2020 / 071361:

[0054] [In formula (23), A １ , A ２ , A ３ , A ４ , A ５ and A ６ each independently represents a hydrogen atom, a methyl group, or an ethyl group; Y １ is expressed by equation (24), equation (25), equation (26) or equation (27): [(In formulas (24) to (27), R ４ and R ５ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group, or a phenyl group, and the phenyl group may be substituted with at least one group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, a hydroxy group, and an alkylthio group having 1 to 6 carbon atoms; and R ４ and R ５ may be bonded to each other to form a ring having 3 to 6 carbon atoms, and R ６represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group, or a phenyl group, and the phenyl group may be substituted with at least one group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, a hydroxy group, and an alkylthio group having 1 to 6 carbon atoms, and Q is represented by formula (28) or formula (29): [In formulas (28) and (29), Q １ represents an alkylene group having 1 to 10 carbon atoms, a phenylene group, a naphthylene group, or an anthrylene group, and the phenylene group, naphthylene group, and anthrylene group may each be substituted with at least one group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, a hydroxy group, and an alkylthio group having 1 to 6 carbon atoms; ４ and n ５ each independently represents the number 0 or 1, Y ２ represents formula (24), formula (25) or formula (27)].

[0055] For other information regarding this polymer, the contents of WO 2020 / 071361 are incorporated herein by reference.

[0056] (1-3-6) Examples of acrylic acid-based polymers used in the resist underlayer film-forming composition of one embodiment of the present invention include polymers containing a structural unit represented by the following formula (1) and a structural unit having a crosslinking moiety represented by the following formula (2), which are described in WO 2012 / 017790:

[0057] Here, in formula (1), R １ represents a hydrogen atom or a methyl group, A represents an alkylene group having 1 to 13 carbon atoms or a phenylene group, Y represents a nitrogen atom or a phosphorus atom, R ２ , R ３ and R ４ each independently represents a hydrogen atom, an alkyl group having 1 to 13 carbon atoms, or a phenyl group; X -represents an anion selected from the group consisting of an alkylsulfonate anion having 1 to 13 carbon atoms, an alkylsulfate anion having 1 to 13 carbon atoms, a chloride anion, a bromide anion, a fluoroalkylsulfonate anion having 1 to 13 carbon atoms, a boron tetrafluoride anion, a phosphorus hexafluoride anion, and an alkylcarboxylate anion having 1 to 13 carbon atoms, wherein in formula (2), R represents a hydrogen atom or a methyl group, and D represents a linear, branched, or cyclic hydrocarbon group having 1 to 13 carbon atoms, the hydrocarbon group having at least one hydroxy group as a substituent.

[0058] For other information regarding this polymer, the contents of WO 2012 / 017790 are incorporated herein by reference.

[0059] (1-3-7) Another acrylic acid-based polymer that can be used in the resist underlayer film-forming composition of one embodiment of the present invention is a polymer having structural units represented by the following (A), (B-1), and (C-1) described in JP-A-2004-309561: (wherein, X represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a halogen atom, a hydroxy group, an alkoxy group having 1 to 5 carbon atoms, an acetyl group, or a cyano group; R ７ represents an alkyl group having 2 to 6 carbon atoms and having at least one hydroxy group, a hydrogen atom, or a glycidyl group; s represents a number from 1 to 5; q1 and r1 are the numbers of structural units contained in the polymer, each of which represents a number from 1 to 3,000; R １ represents a hydrogen atom, a methyl group, an ethyl group, or a chlorine atom; R ２、 R ３ each represents a hydrogen atom, a methyl group, or an ethyl group; R ４ each represents a hydrogen atom, a methyl group, an ethyl group, or a chlorine atom, L represents a polycyclic alicyclic structure, m represents the number 0 or 1, and p represents the number of structural units contained in the polymer and represents a number from 1 to 3000.) Other examples include polymers having structural units represented by the following (A), (B-2), and (C-1):

[0060] (wherein B is —CH ２- or -O-, or a direct bond; q2 is the number of structural units contained in the polymer and is a number of 1 to 3,000; Ar is a benzene ring, a naphthalene ring, or an anthracene ring which may be substituted with an alkyl group having 1 to 5 carbon atoms, a halogen atom, a hydroxy group, an alkoxy group having 1 to 5 carbon atoms, an acetyl group, or a cyano group; R １ , R ２ , R ３ , R ４ , R ７ , m, p and r1 have the same meanings as above.

[0061] (1-3-8) The ends of the polymer chains used in the resist underlayer film-forming composition of one embodiment of the present invention may be capped with a compound containing an aliphatic ring, the aliphatic ring may be substituted with a substituent, or the carbon-carbon bond of the aliphatic ring may be interrupted with a heteroatom.

[0062] The aliphatic ring is preferably a monocyclic or polycyclic aliphatic ring having 3 to 10 carbon atoms, and the polycyclic aliphatic ring is preferably a bicyclic or tricyclic ring.

[0063] The aliphatic ring preferably has at least one unsaturated bond.

[0064] Specific examples of such aliphatic rings include polymer ends derived from carboxyl group-containing compounds containing aliphatic rings, such as the following: Such compounds can bond to polymer ends having functional groups capable of forming chemical bonds with carboxyl groups, such as hydroxyl groups or amino groups, to form new polymer ends.

[0065] In addition, details of the compound containing an aliphatic ring in which the carbon-carbon bond may be interrupted by a heteroatom and may be substituted with a substituent are as described in WO 2020 / 226141.

[0066] (1-3-9) Furthermore, the end of the polymer chain used in the resist underlayer film-forming composition of one embodiment of the present invention may have a structure represented by the following formula (31) or (32) described in WO 2020 / 071361. Having a polymer end with such a structure further makes it possible to suppress deterioration of LWR [line width roughness, line width roughness, line width fluctuation (roughness)] during resist pattern formation.

[0067] [In the above formulas (31) and (32), X is a divalent organic group, A is an aryl group having 6 to 40 carbon atoms, and R １ is a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, and R ２ and R ３ are each independently a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, or an optionally substituted aryl group having 6 to 40 carbon atoms, n1 and n3 are each independently an integer of 1 to 12, and n2 is an integer of 0 to 11.

[0068] (1-3-9-1) A compound having the partial structure represented by the above formula (31) is represented, for example, by the following formula (1-1): Such a compound can form a new polymer end by bonding to a polymer end having a functional group capable of forming a chemical bond with a carboxyl group, such as a hydroxyl group or an amino group.

[0069] [In the above formula (1-1), X is a divalent organic group, A is an aryl group having 6 to 40 carbon atoms, and R １ represents a halogen atom, an alkyl group having 1 to 40 carbon atoms, or an alkoxy group having 1 to 40 carbon atoms, n1 represents an integer of 1 to 12, and n2 represents an integer of 0 to 11.

[0070] Specific examples of the compound represented by the above formula (1-1) are as follows.

[0071] (1-3-9-2) A compound having the partial structure represented by the above formula (32) is represented, for example, by the following formula (2-1): Such a compound can form a new polymer end by bonding to a polymer end having a functional group capable of forming a chemical bond with a carboxyl group, such as a hydroxyl group or an amino group.

[0072] [In the above formula (2-1), X is a divalent organic group, A is an aryl group having 6 to 40 carbon atoms, and R ２ and R ３ are each independently a hydrogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, an optionally substituted aryl group having 6 to 40 carbon atoms, or a halogen atom; ３ is an integer from 1 to 12.

[0073] Specific examples of the compound represented by the above formula (2-1) are as follows. For other information regarding this terminal structure, the contents of WO 2020 / 071361 are incorporated by reference into this application.

[0074] (1-3-10) Furthermore, the end of the polymer chain used in the resist underlayer film forming composition of one embodiment of the present invention may have a structure represented by the following formula (41) or (42). By having a polymer end with such a structure, it is possible to further prevent intermixing with the resist film formed on the upper layer.

[0075] [In formula (41) and formula (42), R １ represents an alkyl group having 1 to 6 carbon atoms, a phenyl group, a pyridyl group, a halogeno group, or a hydroxy group, which may have a substituent; R ２ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a hydroxy group, a halogeno group, or an ester group represented by -C(=O)O-X, where X represents an alkyl group having 1 to 6 carbon atoms which may have a substituent, R ３ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a hydroxy group, or a halogeno group; R ４ represents a direct bond or a divalent organic group having 1 to 8 carbon atoms; R ５represents a divalent organic group having 1 to 8 carbon atoms, A represents an aromatic ring or an aromatic heterocycle, t represents 0 or 1, and u represents 1 or 2.

[0076] For detailed information regarding the above formulas (41) and (42), the disclosure of WO 2015 / 163195 is incorporated herein by reference.

[0077] The compounds having the partial structures represented by the above formulas (41) and (42) are represented, for example, by the compound represented by the following formula (41a) and / or the compound represented by the following formula (42a): Such compounds can form new polymer ends by bonding to polymer ends having functional groups capable of forming chemical bonds with carboxy groups, such as hydroxy groups and amino groups.

[0078] [The meanings of the symbols in the above formulas (41a) and (42a) are as explained in the above formulas (41) and (42)]

[0079] (1-3-10-1) Examples of the compound represented by formula (41a) include compounds represented by the following formula:

[0080] (1-3-10-2) Examples of the compound represented by formula (42a) include compounds represented by the following formula:

[0081]

[0082] (1-3) Crosslinking Agent (C) (1-3-1) Typical crosslinking agents include aminoplast crosslinking agents and phenoplast crosslinking agents.

[0083] As the crosslinking agent, a crosslinking agent having high heat resistance can be used, and as the crosslinking agent having high heat resistance, a compound containing a crosslink-forming substituent having an aromatic ring (e.g., a benzene ring or a naphthalene ring) in the molecule can be preferably used.

[0084] (I-3-2) (1-3-2-1) Aminoplast crosslinking agents include highly alkylated, alkoxylated, alkoxyalkylated, or hydroxyalkylated melamine, benzoguanamine, glycoluril, urea, thiourea, and polymers thereof, which have at least two, and preferably four or more, crosslink-forming substituents.

[0085] For example, the following compounds can be specifically mentioned:

[0086] Methoxymethylated glycoluril [= 1,3,4,6-tetrakis(methoxymethyl)glycoluril, tetramethoxymethyl glycoluril, POWDERLINK (registered trademark) 1174)], butoxymethylated glycoluril [= 1,3,4,6-tetrakis(butoxymethyl)glycoluril], methoxymethylated melamine (= hexamethoxymethylmelamine), butoxymethylated melamine, methoxymethylated benzoguanamine (= tetramethoxymethylbenzoguanamine), butoxymethylated benzoguwanamine, methoxymethylated urea (= 1,1,3,3-tetrakis(methoxymethyl)urea), butoxymethylated urea (= 1,1,3,3-tetrakis(butoxymethyl)urea), 1,3-bis(hydroxymethyl)urea, methoxymethylated thiourea, or methoxymethylated thiourea

[0087] (1-3-2-2) The aminoplast crosslinking agent may have 2 to 6 alkoxyalkyl substituents represented by the following formula (51), which are described in WO 2017 / 187969, per molecule.

[0088] (In formula (51), R １ represents a methyl group or an ethyl group.

[0089] The nitrogen-containing compound having 2 to 6 substituents represented by the formula (51) in one molecule may be a glycoluril derivative represented by the following formula (1A).

[0090] [In formula (1A), four R １ each independently represents a methyl group or an ethyl group, R２ and R ３ each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group.

[0091] Examples of the glycoluril derivative represented by the formula (1A) include compounds represented by the following formulas (1A-1) to (1A-6).

[0092] The compound represented by formula (1A) can be obtained by reacting a nitrogen-containing compound having, in one molecule, 2 to 6 substituents bonded to a nitrogen atom and represented by formula (52) below with at least one compound represented by formula (53) below to produce a nitrogen-containing compound having, in one molecule, 2 to 6 substituents represented by formula (51) below: [In formula (52) and formula (53), R １ represents a methyl group or an ethyl group, R ４ represents an alkyl group having 1 to 4 carbon atoms.

[0093] The glycoluril derivative represented by the formula (1A) can be obtained by reacting a glycoluril derivative represented by the following formula (2A) with at least one compound represented by the formula (53).

[0094] The nitrogen-containing compound having 2 to 6 substituents represented by the formula (52) in one molecule is, for example, a glycoluril derivative represented by the following formula (2A).

[0095] [In formula (2A), R ２ and R ３ each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group; R ４ each independently represents an alkyl group having 1 to 4 carbon atoms.

[0096] Examples of the glycoluril derivative represented by the formula (2A) include compounds represented by the following formulas (2A-1) to (2A-4).

[0097] Further, examples of the compound represented by the formula (53) include compounds represented by the following formulas (3-1) and (3-2). Other nitrogen atoms bonded to the following formula (51) The details of the nitrogen-containing compound having 2 to 6 substituents represented by the following formula (I) in one molecule are in accordance with the contents described in WO 2017 / 187969.

[0098] (1-3-3) (1-3-3-1) Phenoplast crosslinking agents include highly alkylated, alkoxylated, or alkoxyalkylated aromatics, their polymers, and the like. Preferred crosslinking agents have at least two crosslink-forming substituents per molecule, such as 2,6-dihydroxymethyl-4-methylphenol, 2,4-dihydroxymethyl-6-methylphenol, bis(2-hydroxy-3-hydroxymethyl-5-methylphenyl)methane, bis(4-hydroxy-3-hydroxymethyl-5-methylphenyl)methane, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, bis(3-formyl-4-hydroxyphenyl)methane, bis(4-hydroxy-2,5-dimethylphenyl)formylmethane, and α,α-bis(4-hydroxy-2,5-dimethylphenyl)-4-formyltoluene. Condensates of these compounds can also be used.

[0099] (1-3-3-2) In addition to the compounds mentioned above, examples of such compounds include compounds having a partial structure of the following formula (4) and polymers or oligomers having a repeating unit of the following formula (5).

[0100] The above R １１ , R １２ , R １３ , and R １４ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the above-mentioned examples of these alkyl groups can be used. n1 is an integer of 1 to 4, n2 is an integer of 1 to (5-n1), and (n1+n2) is an integer of 2 to 5. n3 is an integer of 1 to 4, n4 is an integer of 0 to (4-n3), and (n3+n4) is an integer of 1 to 4. Oligomers and polymers having a repeating unit structure number of 2 to 100 or 2 to 50 can be used.

[0101] (1-3-3-3) Some specific examples are as follows:

[0102]

[0103] (1-3-3) The crosslinking agents such as aminoplast crosslinking agents and phenoplast crosslinking agents may be used alone or in combination of two or more. The aminoplast crosslinking agent may be produced by a known method or a method equivalent thereto, or a commercially available product may be used.

[0104] The amount of the crosslinking agent, such as an aminoplast crosslinking agent or a phenoplast crosslinking agent, used varies depending on the coating solvent used, the base substrate used, the required solution viscosity, the required film shape, and the like, but the content of the crosslinking agent is, for example, 1% by mass to 50% by mass, and preferably 5% by mass to 30% by mass, relative to the solid content of the resist underlayer film-forming composition.

[0105] (1-4) Curing Catalyst (D) (1-4-1) As the curing catalyst contained in the resist underlayer film-forming composition, an acid or an acid generator can be used, but it is preferable to use an acid generator.

[0106] As the acid generator, either a thermal acid generator or a photoacid generator can be used, but it is preferable to use a thermal acid generator.

[0107] (1-4-2) Examples of thermal acid generators include 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, K-PURE (registered trademark) CXC-1612, CXC-1614, TAG-2172, TAG-2179, TAG-2678, TAG2689, and TAG2700 (manufactured by King Industries), and SI-45, SI-60, SI-80, SI-100, SI-110, and SI-150 (manufactured by Sanshin Chemical Industry Co., Ltd.), organic sulfonate alkyl esters such as methyl 4-phenolsulfonate, and sulfonate salts such as pyridinium-p-toluenesulfonate and pyridinium-p-hydroxybenzenesulfonate.

[0108] (1-4-3) Examples of the photoacid generator include onium salt compounds, sulfonimide compounds, and disulfonyldiazomethane compounds.

[0109] Examples of the onium salt compound include iodonium salt compounds such as diphenyliodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-normal butanesulfonate, diphenyliodonium perfluoro-normal octanesulfonate, diphenyliodonium camphorsulfonate, bis(4-tert-butylphenyl)iodonium camphorsulfonate, and bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate; and sulfonium salt compounds such as triphenylsulfonium hexafluoroantimonate, triphenylsulfonium nonafluoro-normal butanesulfonate, triphenylsulfonium camphorsulfonate, and triphenylsulfonium trifluoromethanesulfonate.

[0110] Examples of the sulfonimide compound include N-(trifluoromethanesulfonyloxy)succinimide, N-(nonafluoronormalbutanesulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, and N-(trifluoromethanesulfonyloxy)naphthalimide.

[0111] Examples of the disulfonyldiazomethane compound include bis(trifluoromethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(2,4-dimethylbenzenesulfonyl)diazomethane, and methylsulfonyl-p-toluenesulfonyldiazomethane.

[0112] (1-4-4) The curing catalyst may be used alone or in combination of two or more.

[0113] The content of the curing catalyst is, for example, 0.1 to 50 parts by mass, and preferably 1 to 30 parts by mass, based on the solid content of the resist underlayer film-forming composition.

[0114] (1-5) Solvent (E) Examples of organic solvents contained in the resist underlayer film-forming composition of the present invention include alkylene glycol monoalkyl ethers and monocarboxylic acid esters thereof, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, and propylene glycol propyl ether acetate; propylene glycol, toluene, xylene, and methyl ethyl ketone. , methyl isobutyl ketone, cyclopentanone, cyclohexanone, cycloheptanone, 4-methyl-2-pentanol, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, ethyl ethoxyacetate, 2-hydroxyethyl acetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, 2-heptanone, methoxycyclopentane, anisole, γ-butyrolactone, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide. These solvents can be used alone or in combination of two or more.

[0115] Among these solvents, alkylene glycol monoalkyl ethers such as propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate, and their monocarboxylic acid esters; ethyl lactate, butyl lactate, and cyclohexanone are preferred.

[0116] In particular, alkylene glycol monoalkyl ethers and their monocarboxylic acid esters are preferred, and propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate are more preferred.

[0117] (1-6) Other Components (1-6-1) A surfactant may be further added to the resist underlayer film-forming composition of one embodiment of the present invention in order to prevent pinholes, striations, and the like from occurring and to further improve the coatability against surface irregularities.

[0118] Examples of surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkyl aryl ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether; polyoxyethylene-polyoxypropylene block copolymers; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate; polyoxyethylene sorbitan monolaurate; polyoxyethylene sorbitan monopalmitate; nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters, such as polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate; fluorine-based surfactants such as Eftop EF301, EF303, and EF352 (trade names, manufactured by Tochem Products Co., Ltd.), Megafac F171, F173, and R-30 (trade names, manufactured by Dainippon Ink Co., Ltd.), Fluorad FC430 and FC431 (trade names, manufactured by Sumitomo 3M Limited), Asahiguard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (trade names, manufactured by Asahi Glass Co., Ltd.); and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.). The amount of these surfactants to be added is usually 2.0 mass % or less, and preferably 1.0 mass % or less, based on the total solid content of the resist underlayer film-forming composition of the present invention. These surfactants may be added alone or in combination of two or more.

[0119] (1-6-2) The solid content (film-forming components) in the resist underlayer film-forming composition used in the present invention is, for example, 0.01 to 50 mass %, or 0.05 to 10 mass %, or 0.1 to 5 mass %. Here, the solid content is the total content of all components of the resist underlayer film-forming composition excluding the solvent.

[0120] (1-6-3) When the resist underlayer film forming composition of one embodiment of the present invention is used for EB or EUV lithography, it is preferably used to form a resist underlayer film for EB or EUV lithography having a film thickness of 10 nm or less.

[0121] [2] Resist underlayer film, laminate (2-1) The resist underlayer film of one embodiment of the present invention is a cured product of a coating film comprising the resist underlayer film-forming composition described above, and can be produced by applying the resist underlayer film-forming composition to a base material such as a semiconductor substrate and baking the composition. The resist underlayer film is particularly suitable for use as a resist underlayer film for EB or EUV lithography.

[0122] A laminate having the substrate and the resist underlayer film is also one aspect of the present invention.

[0123] An example of a substrate to which the resist underlayer film-forming composition of one embodiment of the present invention is applied is a semiconductor substrate. Examples of the semiconductor substrate include a silicon wafer, a germanium wafer, and a compound semiconductor wafer such as gallium arsenide, indium phosphide, gallium nitride, indium nitride, or aluminum nitride.

[0124] When a semiconductor substrate having an inorganic film formed on its surface is used, the inorganic film can be formed by, for example, ALD (atomic layer deposition), CVD (chemical vapor deposition), reactive sputtering, ion plating, vacuum deposition, or spin coating (spin-on glass: SOG). Examples of the inorganic film include a polysilicon film, a silicon oxide film, a silicon nitride film, a BPSG (Boro-Phospho Silicate Glass) film, a titanium nitride film, a titanium nitride oxide film, a tungsten film, a gallium nitride film, and a gallium arsenide film.

[0125] A resist underlayer film-forming composition according to one embodiment of the present invention is applied onto such a semiconductor substrate by a suitable application method such as a spinner or coater. The composition is then baked using a heating means such as a hot plate to form a resist underlayer film. Baking conditions are appropriately selected from a baking temperature of 100°C to 400°C and a baking time of 0.3 minutes to 60 minutes. A baking temperature of 120°C to 350°C and a baking time of 0.5 minutes to 30 minutes are preferred, and a baking temperature of 150°C to 300°C and a baking time of 0.8 minutes to 10 minutes are more preferred.

[0126] The thickness of the resist underlayer film to be formed may be, for example, 0.001 μm (1 nm) to 10 μm, 0.002 μm (2 nm) to 1 μm, 0.005 μm (5 nm) to 0.5 μm (500 nm), 0.001 μm (1 nm) to 0.05 μm (50 nm), 0.002 μm (2 nm) to 0.05 μm (50 nm), 0.003 μm (1 nm) to 0.05 μm (50 nm), ) to 0.05 μm (50 nm), 0.004 μm (4 nm) to 0.05 μm (50 nm), 0.005 μm (5 nm) to 0.05 μm (50 nm), 0.003 μm (3 nm) to 0.03 μm (30 nm), 0.003 μm (3 nm) to 0.02 μm (20 nm), and 0.005 μm (5 nm) to 0.02 μm (20 nm). If the baking temperature is lower than the above range, crosslinking will be insufficient. On the other hand, if the baking temperature is higher than the above range, the resist underlayer film may be decomposed by heat.

[0127] (2-2) The resist underlayer film-forming composition according to one embodiment of the present invention contains a phenolic antioxidant (A). By baking after application, the polymer and the phenolic antioxidant (A) are chemically bonded to each other by a crosslinking agent in the presence of an acid derived from a curing catalyst, forming a cured film. Here, the phenolic antioxidant (A) is lipophilic due to a substituent such as an alkyl group or a halogeno group, and thus tends to migrate to the film surface during the formation of the cured film. This allows for the production of a resist underlayer film with a high probability of the phenolic antioxidant (A) structure being present on the surface. Without being bound by theory, this is believed to improve the antioxidant properties of the resist underlayer film and suppress deterioration of LWR (Line Width Roughness) during resist pattern formation due to diffusion of the composition.

[0128] Whether or not the phenol-based antioxidant is present on the surface of the resist underlayer film can be estimated by measuring the contact angle of the surface of the resist underlayer film with water. The contact angle with water is preferably 55° or more, more preferably 57° or more.

[0129] [3] Method for manufacturing a semiconductor device (3-1) A method for manufacturing a semiconductor device according to one aspect of the present invention is characterized by comprising the steps of: forming, on a semiconductor substrate, a resist underlayer film that is a cured product of a coating film made of the resist underlayer film-forming composition according to another aspect of the present invention; and forming a resist film on the resist underlayer film.

[0130] Furthermore, the method for manufacturing a semiconductor device according to one aspect of the present invention further includes the steps of: exposing the resist film; developing the exposed resist film to form a resist pattern; and etching the resist underlayer film through the formed resist pattern to form a patterned resist underlayer film.

[0131] (3-2) The step of forming a resist underlayer film, which is a cured product of a coating film made of a resist underlayer film-forming composition, on a semiconductor substrate is as described above in (2-1).

[0132] (3-3) The step of forming a resist film on the resist underlayer film is carried out by a known coating and baking method. The photoresist to be formed is not particularly limited as long as it is sensitive to light or electron beams used for exposure.

[0133] Both negative and positive photoresists can be used, including positive photoresists made from a novolak resin and a 1,2-naphthoquinone diazide sulfonic acid ester, chemically amplified photoresists made from a binder having a group that decomposes in the presence of an acid to increase the alkaline dissolution rate and a photoacid generator, chemically amplified photoresists made from a low molecular weight compound that decomposes in the presence of an acid to increase the alkaline dissolution rate of the photoresist, an alkali-soluble binder, and a photoacid generator, chemically amplified photoresists made from a binder having a group that decomposes in the presence of an acid to increase the alkaline dissolution rate of the photoresist, a low molecular weight compound that decomposes in the presence of an acid to increase the alkaline dissolution rate of the photoresist, and a photoacid generator, and resists containing metal elements.

[0134] Examples of such photoresists include V146G (trade name) manufactured by JSR Corporation, APEX-E (trade name) manufactured by Shipley, PAR710 (trade name) manufactured by Sumitomo Chemical Co., Ltd., and AR2772 and SEPR430 (trade names) manufactured by Shin-Etsu Chemical Co., Ltd. Further examples include fluorine-containing polymer photoresists such as those described in Proc. SPIE, Vol. 3999, 330-334 (2000), Proc. SPIE, Vol. 3999, 357-364 (2000), and Proc. SPIE, Vol. 3999, 365-374 (2000).

[0135] Also, International Publication Nos. WO 2019 / 188595, WO 2019 / 187881, WO 2019 / 187803, WO 2019 / 167737, WO 2019 / 167725, WO 2019 / 187445, WO 2019 / 167419, WO 2019 / 123842, WO 2019 / 054282, WO 2019 / 058945, WO 2019 / 058890, WO 2019 / 039290, WO 2019 / 044259, WO No. 2019 / 044231, WO 2019 / 026549, WO 2018 / 193954, WO 2019 / 172054, WO 2019 / 021975, WO 2018 / 230334, WO 2018 / 194123, JP 2018-180525, WO 2018 / 190088, JP 2018-070596, JP 2018-028090, JP 2016-153409, JP 2016-130240, JP 2016-108325, JP 2016-047920, JP 20 16-035570, JP 2016-035567, JP 2016-035565, JP 2019-101417, JP 2019-117373, JP 2019-052294, JP 2019-008280, JP 2019-008279, JP 2019-003176, JP 2019-003175, JP 2018-197853, JP 2019-191298, JP 2019-061217, JP 2018-045152, JP 2018-022039, JP 2016-090441, JP 2015-10878, JP 2012-1 68279, JP 2012-022261, JP 2012-022258, JP 2011-043749, JP 2010-181857, JP 2010-128369, WO 2018 / 031896, JP 2019-113855, WO 2017 / 156388, WO 2017 / 066319, JP 2018-41099, WO 2016 / 065120, WO 2015 / 026482, JP 2016-29498, JP 2011-253185, and other resist compositions and radiation-sensitive resin compositions;So-called resist compositions, such as high-resolution patterning compositions based on organometallic solutions, metal-containing resist compositions, etc., can be used, but are not limited to these.

[0136] (3-4) A pattern forming method according to one embodiment of the present invention includes at least the following steps:

[0137] a step of forming a resist underlayer film on a semiconductor substrate using a resist underlayer film-forming composition according to one embodiment of the present invention; a step of forming a resist film on the resist underlayer film using a resist, preferably a resist for EB or EUV lithography; a step of exposing the resist film, i.e., irradiating the resist film with light or an electron beam (preferably EB or EUV), and then developing the resist film to obtain a resist pattern; and a step of etching the resist underlayer film using the resist pattern as a mask.

[0138] (3-5) In the process of developing the exposed resist film to form a resist pattern, an alkaline developer is used, with the development temperature being appropriately selected from 5°C to 50°C and the development time being appropriately selected from 10 seconds to 300 seconds. Examples of alkaline developers that can be used include aqueous solutions of inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia; primary amines such as ethylamine and n-propylamine; secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and choline; and cyclic amines such as pyrrole and piperidine. Furthermore, the aqueous solutions of the above alkaline solutions can also be used by adding appropriate amounts of alcohols such as isopropyl alcohol and surfactants such as nonionic surfactants. Among these, preferred developers are quaternary ammonium salts, more preferably tetramethylammonium hydroxide and choline. Furthermore, surfactants and the like can also be added to these developers. Alternatively, an organic solvent such as butyl acetate may be used instead of an alkaline developer to develop the portions of the photoresist where the alkaline dissolution rate is not improved. Through the above steps, a substrate having the resist patterned thereon can be produced.

[0139] (3-5) In the step of forming a patterned resist underlayer film by etching the resist underlayer film through the formed resist pattern, the resist underlayer film is etched using the formed resist pattern as a mask.

[0140] In this case, if an inorganic film is formed on the surface of the semiconductor substrate used, the surface of the inorganic film is exposed, and if an inorganic film is not formed on the surface of the semiconductor substrate used, the surface of the semiconductor substrate is exposed. Thereafter, the substrate is processed by a method known per se (e.g., dry etching), whereby a semiconductor device can be manufactured.

[0141] The weight average molecular weight of the polymer shown in Synthesis Example 1 below in this specification is the result of measurement by gel permeation chromatography (hereinafter abbreviated as GPC). For the measurement, a GPC device manufactured by Tosoh Corporation was used, and the measurement conditions etc. are as follows.

[0142] GPC column: Shodex KF803L, Shodex KF802, Shodex KF801 (registered trademark) (Showa Denko K.K.) Column temperature: 40°C Solvent: N,N-dimethylformamide (DMF) Flow rate: 0.6 ml / min Standard sample: polystyrene (manufactured by Tosoh Corporation)

[0143] Synthesis Example 1 8.00 g of monoallyl diglycidyl isocyanuric acid (manufactured by Shikoku Chemical Industry Co., Ltd.), 5.45 g of diethylbarbituric acid (manufactured by Tokyo Chemical Industry Co., Ltd.), and 0.48 g of tetrabutylphosphonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to 56.00 g of propylene glycol monomethyl ether and dissolved. After replacing the atmosphere in the reaction vessel with nitrogen, the mixture was reacted by heating under reflux for 10 hours to obtain a polymer solution. The polymer solution did not become cloudy even when cooled to room temperature, and had good solubility in propylene glycol monomethyl ether. GPC analysis revealed that the polymer in the obtained solution had a weight-average molecular weight of 10,000 in terms of standard polystyrene. The polymer obtained in this synthesis example has structural units represented by the following formulas (1a) and (1b).

[0144]

[0145] Example 1 0.33 g of the polymer solution obtained in Synthesis Example 1 above was mixed with 0.04 g of tetramethoxymethylglycoluril (manufactured by Nippon Cytec Industries Co., Ltd.), 0.004 g of p-phenolsulfonic acid pyridinium salt (1:1), and 0.007 g of tris-1,1,3-(2-methyl-4-hydroxy-5-tert-butylphenyl)butane (1c) [ADK STAB (registered trademark) AO-30 (manufactured by ADEKA Corporation)], and 27.20 g of propylene glycol monomethyl ether and 11.98 g of propylene glycol monomethyl ether acetate were added and dissolved. The mixture was then filtered using a polyethylene microfilter with a pore size of 0.05 μm to obtain a resist underlayer film-forming composition for lithography.

[0146]

[0147] Example 2 0.31 g of the polymer solution obtained in Synthesis Example 1 above was mixed with 0.03 g of tetramethoxymethylglycoluril (manufactured by Nippon Cytec Industries Co., Ltd.), 0.003 g of p-phenolsulfonic acid pyridinium salt (1:1), and 0.02 g of tris-1,1,3-(2-methyl-4-hydroxy-5-tert-butylphenyl)butane (1c) [ADK STAB (registered trademark) AO-30 (manufactured by ADEKA Corporation)], and 27.16 g of propylene glycol monomethyl ether and 11.98 g of propylene glycol monomethyl ether acetate were added and dissolved. The mixture was then filtered using a polyethylene microfilter with a pore size of 0.05 μm to obtain a resist underlayer film-forming composition for lithography.

[0148] Comparative Example 1 0.34 g of the polymer solution obtained in Synthesis Example 1 above was mixed with 0.01 g of tetramethoxymethyl glycoluril (manufactured by Nippon Cytec Industries Co., Ltd.) and 0.001 g of p-phenolsulfonic acid pyridinium salt (1:1), and 27.24 g of propylene glycol monomethyl ether and 11.98 g of propylene glycol monomethyl ether acetate were added and dissolved. The mixture was then filtered using a polyethylene microfilter with a pore size of 0.05 μm to obtain a resist underlayer film-forming composition for lithography.

[0149] [Elution Test in Photoresist Solvent] Each of the resist underlayer film-forming compositions of Example 1, Example 2, and Comparative Example 1 was applied to a silicon wafer, which is a semiconductor substrate, using a spinner. The silicon wafer was placed on a hot plate and baked at 205°C for 1 minute to form a resist underlayer film (film thickness: 5 nm). These resist underlayer films were immersed in ethyl lactate and propylene glycol monomethyl ether, which are solvents used in photoresists, and it was confirmed that they were insoluble in these solvents.

[0150] [Contact Angle Measurement] The resist underlayer film forming compositions of Example 1, Example 2, and Comparative Example 1 were each applied onto a silicon wafer, which was a semiconductor substrate, using a spinner. The silicon wafer was placed on a hot plate and baked at 205°C for 1 minute to form a resist underlayer film (film thickness 5 nm). The contact angle of pure water on each resist underlayer film was measured using a contact angle meter (device name: DM-701 (manufactured by Kyowa Scientific Co., Ltd.) when pure water was dropped onto the film. The results are shown in Table 1. These results indicate that, compared to Comparative Example 1, Examples 1 and 2 became more hydrophobic as the amount of additive added increased, and that the additive (compound represented by formula (1c)) remained in the film even after baking.

[0151]

[0152] [Formation of Positive Resist Pattern Using Electron Beam Lithography Apparatus] The resist underlayer film forming compositions of Examples 1, 2, and Comparative Example 1 were each applied to a silicon wafer using a spinner. The silicon wafer was baked on a hot plate at 205°C for 60 seconds to obtain a 5 nm-thick resist underlayer film. An EUV positive resist solution (containing a methacrylic polymer) was spin-coated onto the resist underlayer film and heated at 130°C for 60 seconds to form an EUV resist film. The resist film was exposed under specified conditions using an electron beam lithography apparatus (ELS-G130). After exposure, the resist film was baked at 100°C for 60 seconds (PEB), cooled to room temperature on a cooling plate, and developed with an alkaline developer (2.38% TMAH), forming a 22 nm line pattern / 44 nm pitch resist pattern. A scanning electron microscope (CG4100, manufactured by Hitachi High-Technologies Corporation) was used to measure the resist pattern. The photoresist patterns thus obtained were observed from above and evaluated. Table 2 shows the LWR for a line pattern with a CD size of 22 nm.

[0153] In Example 1 and Example 2, an improvement effect in LWR in a line pattern with a CD size of 22 nm was confirmed compared with Comparative Example 1. This result demonstrates that the resist underlayer film containing the compound represented by formula (1c) can improve LWR and has good pattern forming ability.

Claims

1. A resist underlayer forming composition comprising: (A) a phenolic antioxidant having at least one substituted hydrogen atom among the ortho or para carbon atoms of a phenolic hydroxyl group on an aryl ring, and having 7 or more carbon atoms; (B) a polymer reactive with a crosslinking agent; (C) a crosslinking agent; (D) a curing catalyst; and (E) a solvent.

2. The phenolic antioxidant (A) is given by the following formulas (I) to (III): 【Chemistry 42】 [In formulas (1) to (III), Each R independently represents an alkyl group or halogeno group having 1 to 10 carbon atoms, which may have substituents. Each Y independently represents a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms which may have substituents, or a halogen group, provided that adjacent R and Y, or two adjacent Ys, are both alkyl groups which may have substituents, they may be bonded to each other to form a ring; if one Y is a hydroxyl group, the other Y on the same benzene ring represents a hydrogen atom, an alkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms which may have substituents, or a halogen group. L represents a (n1 + n2 + n3 + n4 + n5) valency linking group that connects the carbon atoms on the (n1 + n2 + n3 + n4 + n5) benzene rings that make up the phenol ring; n1, n2, n3, n4, and n5 each represent an integer of 0 or more, and the sum of n1, n2, n3, n4, and n5 is 2 or more. The resist underlayer film forming composition according to claim 1, wherein the composition is at least one selected from the group consisting of antioxidants represented by .

3. Equation (I) is the following equation (I-1) or (I-2): 【Chemistry 43】 [The definitions of R and Y in equations (I-1) and (I-2) are the same as in equation (I)] The resist underlayer film forming composition according to claim 2, as represented by [the specified symbol].

4. The resist underlayer film forming composition according to claim 1, wherein polymer (B) is a cyanuric acid-based polymer, a polyester-based polymer, or an acrylic-based polymer.

5. The resist underlayer film forming composition according to claim 1, wherein the crosslinking agent (C) is at least one selected from the group consisting of aminoplast crosslinking agents and phenoplast crosslinking agents.

6. The resist underlayer forming composition according to claim 1, wherein the solvent (E) contains at least one selected from the group consisting of alkylene glycol monoalkyl ethers and monocarboxylic acid esters of alkylene glycol monoalkyl ethers.

7. A resist underlayer film, which is a cured product of a coated film made from the resist underlayer film forming composition according to any one of claims 1 to 6.

8. The resist underlayer film according to claim 7, wherein the contact angle with water is 55° or more.

9. A laminate having a substrate and a resist underlayer film according to claim 7.

10. A laminate having a substrate and a resist underlayer film according to claim 8.

11. A step of forming a resist underlayer film on a semiconductor substrate, which is a cured product of a coating film made of the resist underlayer film forming composition according to any one of Claims 1 to 6, A step of forming a resist film on the resist underlayer film, A method for manufacturing a semiconductor device, characterized by including the following:

12. A step of forming a resist underlayer film on a semiconductor substrate, which is a cured product of a coating film made of the resist underlayer film forming composition according to any one of Claims 1 to 6, A step of forming a resist film on the resist underlayer film, The process of exposing the resist film, A step of developing the resist film after exposure to form a resist pattern, A step of forming a patterned resist underlayer film by etching the resist underlayer film through the formed resist pattern, A method for manufacturing a semiconductor device, characterized by including the following:

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