Method for manufacturing a semiconductor substrate and composition

Abstract

Provided are: a semiconductor substrate production method in which a composition that makes it possible to form a film having excellent etching resistance, heat resistance, and bending resistance is used; and a composition and a resist underlayer film for the semiconductor substrate production method. The semiconductor substrate production method includes a step in which a composition for forming a resist underlayer film is applied directly or indirectly on a substrate, a step in which a resist pattern is formed directly or indirectly on the resist underlayer film formed in the application step, and a step in which etching is performed using the resist pattern as a mask. The composition for forming the resist underlayer film contains: a compound including at least one nitrogen-containing ring structure selected from the group consisting of pyridine ring structures and pyrimidine ring structures, and a partial structure represented by formula (1-1) or formula (1-2); and a solvent. In formulas (1-1) and (1-2), X1 and X2 each independently represent a group represented by formula (i), (ii), (iii), or (iv). * is a bond with a part in the compound other than the partial structure represented by formula (1-1) or (1-2). Ar11 and Ar12 each independently represent a substituted or unsubstituted aromatic ring structure that has 5-20 ring members and forms a condensed ring structure together with two adjacent carbon atoms in formula (1-1) and formula (1-2). In formula (i), R1 and R2 each independently represent a hydrogen atom or a monovalent organic group having 1-20 carbon atoms. In formula (ii), R3 and R4 each independently represent a hydrogen atom or a monovalent organic group having 1-20 carbon atoms. In formula (iii), R5 represents a monovalent organic group having 1-20 carbon atoms. In formula (iv), R6 represents a hydrogen atom or a monovalent organic group having 1-20 carbon atoms.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a semiconductor substrate and a composition.

Background Art

[0002] In the manufacture of semiconductor devices, for example, a multilayer resist process is used in which a resist film laminated via an organic underlayer film, a resist underlayer film such as a silicon-containing film, etc. on a substrate is exposed and developed to form a resist pattern. In this process, the resist underlayer film is etched using this resist pattern as a mask, and the obtained resist underlayer film pattern is used as a mask to further etch the substrate, whereby a desired pattern can be formed on the semiconductor substrate (see Japanese Patent Application Laid-Open No. 2004-177668).

[0003] Regarding the materials used for such a composition for forming a resist underlayer film, various studies have been conducted (see International Publication No. 2011 / 108365).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the multilayer resist process, the organic underlayer film as the resist underlayer film is required to have etching resistance, heat resistance, and bending resistance.

[0006] The present invention has been made based on the above circumstances, and an object thereof is to provide a method for manufacturing a semiconductor substrate using a composition capable of forming a film excellent in etching resistance, heat resistance, and bending resistance, and the composition.

Means for Solving the Problem

[0007] In one embodiment, the present invention includes 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 applying step, a step of performing etching using the resist pattern as a mask, and wherein the composition for forming a resist underlayer film contains a compound (hereinafter also referred to as "[A] compound") including at least one nitrogen-containing ring structure selected from the group consisting of a pyridine ring structure and a pyrimidine ring structure, and a partial structure represented by the following formula (1-1) or (1-2), and a solvent (hereinafter also referred to as "[B] solvent"). The present invention relates to a method for manufacturing a semiconductor substrate.

Chemical Formula

Chemical Formula

[0008] In this specification, "the number of ring members" refers to the number of atoms constituting the ring. For example, the number of ring members of a biphenyl ring is 12, the number of ring members of a naphthalene ring is 10, and the number of ring members of a fluorene ring is 13. "Fused ring structure" refers to a structure in which adjacent rings share one side (two adjacent atoms). "Organic group" refers to a group containing at least one carbon atom.

[0009] In other embodiments, the present invention a compound containing at least one nitrogen-containing ring structure selected from the group consisting of a pyridine ring structure and a pyrimidine ring structure, and a partial structure represented by the following formula (1-1) or (1-2), and a solvent and relates to a composition containing the same.

Chemical formula

Chemical formula

Advantages of the Invention

[0010] According to the method for manufacturing the semiconductor substrate, a resist underlayer film excellent in etching resistance, heat resistance, and bending resistance can be formed, so that a good semiconductor substrate can be obtained. According to the composition, a film excellent in etching resistance, heat resistance, and bending resistance can be formed. Therefore, these can be suitably used for manufacturing semiconductor devices and the like, which are expected to further progress in miniaturization in the future.

Brief Description of the Drawings

[0011]

Figure 1

Embodiments for Carrying Out the Invention

[0012] Hereinafter, the method for manufacturing a semiconductor substrate and the composition according to the embodiments of the present invention will be described in detail.

[0013] 《Method for Manufacturing a Semiconductor Substrate》 The method for manufacturing the semiconductor substrate includes a step of coating a composition for forming a resist underlayer film directly or indirectly on a substrate (hereinafter, also referred to as "coating step"), a step of forming a resist pattern directly or indirectly on the resist underlayer film formed by the coating step (hereinafter, also referred to as "resist pattern forming step"), and a step of performing etching using the resist pattern as a mask (hereinafter, also referred to as "etching step").

[0014] According to the method for manufacturing the semiconductor substrate, by using a predetermined resist underlayer film-forming composition in the coating step, a resist underlayer film excellent in etching resistance, heat resistance, and bending resistance can be formed, so that a semiconductor substrate having a good pattern shape can be manufactured.

[0015] The method for manufacturing the semiconductor substrate may further include a step of heating the resist underlayer film at 250°C or higher (hereinafter also referred to as the "heating step") before forming the resist pattern, if necessary.

[0016] The method for manufacturing the semiconductor substrate may further include a step of forming a silicon-containing film directly or indirectly on the resist underlayer film (hereinafter also referred to as the "silicon-containing film forming step") before forming the resist pattern, if necessary.

[0017] Hereinafter, the resist underlayer film-forming composition used in the method for manufacturing the semiconductor substrate and each step will be described.

[0018] [Resist Underlayer Film-Forming Composition] The resist underlayer film-forming composition contains [A] compound and [B] solvent. The resist underlayer film-forming composition may contain optional components as long as the effects of the present invention are not impaired. By containing the [A] compound, the resist underlayer film-forming composition can form a film excellent in etching resistance, heat resistance, and bending resistance. Therefore, this resist underlayer film-forming composition can be suitably used in a multilayer resist process.

[0019] <[A] Compound> [A] compound includes at least one nitrogen-containing ring structure selected from the group consisting of a pyridine ring structure and a pyrimidine ring structure, and a partial structure represented by the following formula (1-1) or (1-2). The resist underlayer film-forming composition can contain one or more [A] compounds.

Chemical formula

[0020] (Nitrogen-containing ring structure) [A] The compound contains at least one nitrogen-containing ring structure selected from the group consisting of a pyridine ring structure and a pyrimidine ring structure. However, the case where the nitrogen-containing ring structure is the partial structure represented by the above formula (1-1) or (1-2) is excluded. The number of nitrogen-containing ring structures in [A] compound may be 1 or 2 or more. As the form of containing the nitrogen-containing ring structure, a form independently containing their basic ring structures (that is, pyridine ring, pyrimidine ring), a form in which a plurality of ring structures are linked like bipyridine, etc., a form in which a condensed ring structure is formed with other ring structures such as an alicyclic ring structure or an aromatic ring structure, or any combination thereof may be used. From the viewpoints of ease of synthesis and heat resistance of [A] compound, a pyridine ring structure is preferable as the ring structure.)

[0021] The nitrogen-containing ring structure may have a substituent. Examples of the substituent include a monovalent linear hydrocarbon group having 1 to 10 carbon atoms, a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, an alkoxy group such as a methoxy group, an ethoxy group, and a propoxy group, an alkoxycarbonyl group such as a methoxycarbonyl group and an ethoxycarbonyl group, an alkoxycarbonyloxy group such as a methoxycarbonyloxy group and an ethoxycarbonyloxy group, an acyl group such as a formyl group, an acetyl group, a propionyl group, and a butyryl group, a cyano group, a nitro group, and the like.

[0022] (Partial structure) The partial structure is represented by the above formula (1-1) or (1-2). [A] The lower limit of the number of partial structures in the compound is 1, and preferably 2. The upper limit of the number of the above partial structures is not particularly limited, preferably 10, and more preferably 6. When the [A] compound has two or more partial structures, the plurality of partial structures may be the same or different from each other.

[0023] In the above formulas (1-1) and (1-2), X 1 and X 2 are each independently a group represented by the above formula (i), (ii), (iii) or (iv).

[0024] In the above formulas (i), (ii), (iii) and (iv), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 Examples of the monovalent organic group having 1 to 20 carbon atoms represented by include a monovalent hydrocarbon group having 1 to 20 carbon atoms, a group having a divalent heteroatom-containing group between carbon-carbon atoms of this hydrocarbon group, a group in which some or all of the hydrogen atoms of the above hydrocarbon group are substituted with a monovalent heteroatom-containing group, or a combination thereof.

[0025] Examples of the monovalent hydrocarbon groups having 1 to 20 carbon atoms include monovalent chain hydrocarbon groups having 1 to 20 carbon atoms, monovalent alicyclic hydrocarbon groups having 4 to 20 carbon atoms, monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms, or combinations thereof.

[0026] In this specification, the "hydrocarbon group" includes a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. This "hydrocarbon group" includes a saturated hydrocarbon group and an unsaturated hydrocarbon group. The "chain hydrocarbon group" means a hydrocarbon group composed only of a chain structure without including a ring structure, and includes both a straight-chain hydrocarbon group and a branched-chain hydrocarbon group. The "alicyclic hydrocarbon group" means a hydrocarbon group that includes only an alicyclic structure as the ring structure and does not include an aromatic ring structure, and includes both a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic hydrocarbon group (however, it is not necessary to be composed only of an alicyclic structure, and a part thereof may include a chain structure). The "aromatic hydrocarbon group" means a hydrocarbon group that includes an aromatic ring structure as the ring structure (however, it is not necessary to be composed only of an aromatic ring structure, and a part thereof may include an alicyclic structure or a chain structure).

[0027] Examples of the monovalent chain hydrocarbon groups having 1 to 20 carbon atoms include alkyl groups such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, tert-butyl group; alkenyl groups such as ethenyl group, propenyl group, butenyl group; and alkynyl groups such as ethynyl group, propynyl group, butynyl group.

[0028] Examples of the monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms include cycloalkyl groups such as cyclopentyl group, cyclohexyl group; cycloalkenyl groups such as cyclopropenyl group, cyclopentenyl group, cyclohexenyl group; bridged ring saturated hydrocarbon groups such as norbornyl group, adamantyl group, tricyclodecyl group; and bridged ring unsaturated hydrocarbon groups such as norbornenyl group, tricyclodecenyl group.

[0029] Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include phenyl group, tolyl group, naphthyl group, anthracenyl group, pyrenyl group and the like.

[0030] Examples of the heteroatom constituting the divalent or monovalent heteroatom-containing group include, for example, oxygen atom, nitrogen atom, sulfur atom, phosphorus atom, silicon atom, halogen atom and the like. Examples of the halogen atom include fluorine atom, chlorine atom, bromine atom, iodine atom.

[0031] Examples of the divalent heteroatom-containing group include, for example, -CO-, -CS-, -NH-, -O-, -S-, and groups formed by combining these.

[0032] Examples of the monovalent heteroatom-containing group include, for example, hydroxy group, sulfanyl group, cyano group, nitro group, halogen atom and the like.

[0033] In the above formulas (1-1) and (1-2), Ar 11 and Ar 12 are each independently an aromatic ring having 5 to 20 ring members, which may be substituted or unsubstituted, and forms a condensed ring structure together with two adjacent carbon atoms in the above formulas (1-1) and (1-2). Examples of the aromatic ring having 5 to 20 ring members in Ar 11 and Ar 12 include, for example, aromatic hydrocarbon rings such as benzene ring, naphthalene ring, anthracene ring, indene ring, pyrene ring, fluorene ring, and aromatic heterocyclic rings such as furan ring, pyrrole ring, thiophene ring, phosphole ring, pyrazole ring, oxazole ring, isoxazole ring, thiazole ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring and the like. The pyridine ring and pyrimidine ring in Ar 11 and Ar 12 may be present as a component of the nitrogen-containing ring structure of the [A] compound, or may be present as a component separate from the nitrogen-containing ring structure. It is only necessary that the [A] compound as a whole contains a nitrogen-containing ring structure.

[0034] Ar 11 and Ar 12Examples of the substituent include the same substituents as those of the nitrogen-containing ring structure described above.

[0035] [A] compound preferably has at least one selected from the group consisting of a group represented by the following formula (X-1) and a group represented by the following formula (X-2). The lower limit of the total number of the group represented by the following formula (X-1) and the group represented by the following formula (X-2) that [A] compound has is preferably 1, more preferably 2, and even more preferably 3. The upper limit of the total number is preferably 10, more preferably 8, and even more preferably 6. Among them, the compound preferably has at least one group represented by the following formula (X-1). Thereby, the heat resistance of the obtained resist underlayer film can be improved.

Chemical formula

[0036] In the above formulas (X-1) and (X-2), R 7 Examples of the divalent hydrocarbon group having 1 to 18 carbon atoms represented by include groups obtained by removing one hydrogen atom from the groups corresponding to the monovalent hydrocarbon groups in the above formulas (i), (ii), (iii) and (iv) among R 1 R 2 R 3 R 4 R 5 R 6 and R 7 Among them, R

[0037] The group represented by the above formula (X-1) or (X-2) is preferably included in X 1 or X 2 contained in the partial structure represented by the above formula (1-1) or (1-2). R 1 in the above formula (i)and R 2 at least one of the following, R in the above formula (ii) 3 and R 4 at least one of the following, R in the above formula (iii) 5 and R in the above (iv) 6 is preferably a group represented by the above formula (X-1) or (X-2), respectively, independently.

[0038] [A] The compound is preferably represented by the following formula (2-1), (2-2) or (2-3). [Chemical formula] (In the above formulas (2-1), (2-2) and (2-3), X 1 and X 2 are synonymous with the above formulas (1-1) and (1-2), respectively. R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 and R 15 is each independently a monovalent organic group having 1 to 10 carbon atoms. R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 and R 15 When there are a plurality of each of R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 and R 15 are the same as or different from each other. n1, n4, n5, n6, n7 and n8 are each independently an integer of 0 to 4, and n2 and n3 are each independently an integer of 0 to 3. k is each independently 1 or 2. Y is a k-valent organic group having 1 to 20 carbon atoms.)

[0039] In the above formulas (2-1), (2-2) and (2-3), R8 、 R 9 、 R 10 、 R 11 、 R 12 、 R 13 、 R 14 and R 15 Examples of the monovalent organic group having 1 to 10 carbon atoms represented by are, in the above formulas (i), (ii), (iii) and (iv), R 1 、 R 2 、 R 3 、 R 4 、 R 5 and R 6 Among the monovalent organic groups having 1 to 20 carbon atoms represented by, groups corresponding to 1 to 10 carbon atoms are exemplified.

[0040] n1, n4, n5, n6, n7 and n8 are each independently preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0. n2 and n3 are each independently preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0. k is preferably 1.

[0041] In the above formulas (2-1), (2-2) and (2-3), examples of the k-valent organic group having 1 to 20 carbon atoms represented by Y are, in the above formulas (i), (ii), (iii) and (iv), R 1 、 R 2 、 R 3 、 R 4 、 R 5 and R 6Examples thereof include monovalent organic groups having 1 to 20 carbon atoms represented by the formula, or divalent groups obtained by further removing one hydrogen atom from this organic group. Among them, as the k-valent organic group having 1 to 20 carbon atoms represented by Y, a group obtained by removing k hydrogen atoms from a group containing an aromatic hydrocarbon ring having 6 to 20 ring members is preferable, and a group obtained by removing k hydrogen atoms from a group containing a benzene ring, a naphthalene ring, an anthracene ring, a pyrene ring, a fluorene ring or a perylene ring is more preferable. Further, from the viewpoint of improving the resistance to basic hydrogen peroxide water such as a mixed cleaning liquid (SC-1) of aqueous ammonia, hydrogen peroxide water and ultrapure water, a structure in which these rings and a group having an acetal structure are combined, more specifically, a 1,3-benzodioxole structure is also preferable.

[0042] Examples of the [A] compound represented by the above formula (2-1) include compounds represented by the following formulas (2-1-1) to (2-1-7) (hereinafter, also referred to as "compounds (2-1-1) to (2-1-7)").

[0043] [Chemical formula]

[0044] [Chemical formula]

[0045] Examples of the [A] compound represented by the above formula (2-2) include compounds represented by the following formulas (2-2-1) to (2-2-6) (hereinafter, also referred to as "compounds (2-2-1) to (2-2-6)").

[0046] [Chemical formula]

[0047] Examples of the [A] compound represented by the above formula (2-3) include compounds represented by the following formulas (2-3-1) to (2-3-6) (hereinafter, also referred to as "compounds (2-3-1) to (2-3-6)").

[0048] [Chem.]

[0049] Examples of the [A] compound containing a pyridine ring structure other than the structures represented by the above formulas (2-1), (2-2), and (2-3) include structures represented by the following formulas (Z-1-1) to (Z-1-5).

[0050] [Chem.]

[0051] Examples of the [A] compound containing a pyrimidine ring structure include structures represented by the following formulas (Z-2-1) to (Z-2-6).

[0052] [Chem.]

[0053] As the lower limit of the molecular weight of the [A] compound, 400 is preferable, 500 is more preferable, 550 is further preferable, and 600 is particularly preferable. As the upper limit of the molecular weight, 3,000 is preferable, 1,500 is more preferable, and 1,000 is further preferable. By setting the molecular weight of the [A] compound within the above range, the flatness of the resist lower layer film formed by the composition for forming a resist lower layer film can be further improved.

[0054] As the upper limit of the content ratio of hydrogen atoms to all atoms constituting the [A] compound, 5.5% by mass is preferable, 5.2% by mass is more preferable, 5.0% by mass is further preferable, and 4.8% by mass is particularly preferable. As the lower limit of the content ratio, for example, it is 0.1% by mass. By setting the content ratio of hydrogen atoms to all atoms constituting the [A] compound within the above range, the bending resistance of the resist lower layer film formed by the composition for forming a resist lower layer film can be further improved. The content ratio of hydrogen atoms to all atoms constituting the [A] compound is a value calculated from the molecular formula of the [A] compound.

[0055] [A] As the lower limit of the content ratio of the compound, 50% by mass is preferable, 60% by mass is more preferable, and 70% by mass is even more preferable with respect to all components other than [B] the solvent in the composition for forming a resist lower layer film. As the upper limit of the above content ratio, 100% by mass is preferable, but 99% by mass may be used, or 98% by mass may also be used.

[0056] As the lower limit of the content ratio of [A] the compound in the composition for forming a resist lower layer film, 2% by mass is preferable, 4% by mass is more preferable, 5% by mass is even more preferable, and 6% by mass is particularly preferable in the total mass of [A] the compound and [B] the solvent. As the upper limit of the above content ratio, 30% by mass is preferable, 25% by mass is more preferable, 20% by mass is even more preferable, and 18% by mass is particularly preferable in the total mass of [A] the compound and [B] the solvent.

[0057] [Synthesis method of [A] compound] Regarding the synthesis method of [A] the compound, taking as an example the structure in which [A] the compound is represented by the above formula (2-1), X in the above formula (2-1) is represented by the above formula (ii), and the above formula (ii) part has a group represented by the above formula (X-1). Typically, as shown in the following scheme, a substituted pyridine ring is formed by the Crane-K type pyridine synthesis method using an aldehyde, a ketone, and a nitrogen source (amine or ammonium salt), and [A] the compound can be synthesized through the Knoevenagel condensation of the fluorene part and the ethynyl group-containing aldehyde under basic conditions.

[0058] [Chemical formula]

[0059] In the above scheme, Y has the same meaning as the above formula (2-1). Each R is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms. R 7is synonymous with the above formula (X-1). For other structures, they can be appropriately synthesized by changing the structure of Y in the starting aldehyde, the structure of the fluorene part of the ketone, the structure of the ethynyl group-containing aldehyde for modification, etc.

[0060] <[B] Solvent> [B] The solvent is not particularly limited as long as it can dissolve or disperse [A] the compound and any components contained as necessary.

[0061] [B] Examples of the solvent include hydrocarbon solvents, ester solvents, alcohol solvents, ketone solvents, ether solvents, nitrogen-containing solvents, etc. [B] The solvent can be used alone or in combination of two or more.

[0062] Examples of the hydrocarbon solvent include aliphatic hydrocarbon solvents such as n-pentane, n-hexane, cyclohexane, and aromatic hydrocarbon solvents such as benzene, toluene, xylene, etc.

[0063] Examples of the ester solvent include carbonate solvents such as diethyl carbonate, monoester solvents of acetic acid such as methyl acetate, ethyl acetate, lactone solvents such as γ-butyrolactone, polyhydric alcohol partial ether carboxylate solvents such as diethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, and lactate solvents such as methyl lactate, ethyl lactate, etc.

[0064] Examples of the alcohol solvent include monoalcohol solvents such as methanol, ethanol, n-propanol, and polyhydric alcohol solvents such as ethylene glycol, 1,2-propylene glycol, etc.

[0065] Examples of the ketone solvent include chain ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclic ketone solvents such as cyclohexanone.

[0066] Examples of the ether solvents include chain ether solvents such as n-butyl ether, cyclic ether solvents such as tetrahydrofuran, polyhydric alcohol ether solvents, and polyhydric alcohol partial ether solvents such as diethylene glycol monomethyl ether.

[0067] Examples of the nitrogen-containing solvents include chain nitrogen-containing solvents such as N,N-dimethylacetamide and cyclic nitrogen-containing solvents such as N-methylpyrrolidone.

[0068] [B] As the solvent, an ester solvent or a ketone solvent is preferred, a polyhydric alcohol partial ether carboxylate solvent or a cyclic ketone solvent is more preferred, and propylene glycol monomethyl ether acetate or cyclohexanone is even more preferred.

[0069] The lower limit of the content ratio of the [B] solvent in the composition for forming a resist underlayer film is preferably 50% by mass, more preferably 60% by mass, and even more preferably 70% by mass. The upper limit of the above content ratio is preferably 99.9% by mass, more preferably 99% by mass, and even more preferably 95% by mass.

[0070] (Optional component) The composition for forming a resist underlayer film may contain optional components as long as the effects of the present invention are not impaired. Examples of the optional components include acid generators, crosslinking agents, surfactants, etc. The optional components can be used alone or in combination of two or more. The content ratio of the optional components in the composition for forming a resist underlayer film can be appropriately determined according to the type of the optional components and the like.

[0071] [Method for preparing the composition for forming a resist underlayer film] The composition for forming a resist underlayer film can be prepared by mixing the [A] compound, the [B] solvent, and, if necessary, optional components at a predetermined ratio, and preferably filtering the obtained mixture through a membrane filter having a pore size of 0.02 μm to 0.5 μm.

[0072] [Coating process] In this process, a composition for forming a resist underlayer film is applied directly or indirectly onto a substrate. The method for applying the composition for forming a resist underlayer film is not particularly limited, and it can be carried out by an appropriate method such as spin coating, casting, roll coating, etc. Thereby, a coating film is formed, and a resist underlayer film is formed due to volatilization of the solvent and the like.

[0073] Examples of the substrate include metal or semi-metal substrates such as silicon substrates, aluminum substrates, nickel substrates, chromium substrates, molybdenum substrates, tungsten substrates, copper substrates, tantalum substrates, and titanium substrates. Among these, a silicon substrate is preferred. The above substrate may be a substrate on which a silicon nitride film, an alumina film, a silicon dioxide film, a tantalum nitride film, a titanium nitride film, etc. are formed.

[0074] Examples of the case where the composition for forming a resist underlayer film is applied indirectly onto a substrate include the case where the composition for forming a resist underlayer film is applied onto a silicon-containing film described later formed on the above substrate.

[0075] [Heating Process] In this process, before forming a resist pattern, the above resist underlayer film is heated at 250 °C or higher. The formation of the resist underlayer film is promoted by heating the coating film. More specifically, volatilization of the solvent and the like are promoted by heating the coating film.

[0076] The heating of the above coating film may be carried out in an air atmosphere or in a nitrogen atmosphere. As the lower limit of the heating temperature, 250 °C is preferred, 260 °C is more preferred, and 280 °C is even more preferred. As the upper limit of the above heating temperature, 600 °C is preferred, and 500 °C is more preferred. As the lower limit of the time in heating, 15 seconds is preferred, and 30 seconds is more preferred. As the upper limit of the above time, 1,200 seconds is preferred, and 600 seconds is more preferred.

[0077] Note that after the coating process, the resist underlayer film may be exposed. After the coating process, the resist underlayer film may be exposed to plasma. After the coating process, 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.

[0078] The radiation used for exposing the resist underlayer film is appropriately selected from electromagnetic waves such as visible light, ultraviolet rays, far ultraviolet rays, X-rays, and γ-rays; and particle beams such as electron beams, molecular beams, and ion beams.

[0079] Examples of the method for exposing the resist underlayer film to plasma include a direct method by placing the substrate in each gas atmosphere and performing plasma discharge. 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 supplied power is 100 W or more and 1,500 W or less.

[0080] The lower limit of the plasma exposure time is preferably 10 seconds, more preferably 30 seconds, and even more preferably 1 minute. The upper limit of the above time is preferably 10 minutes, more preferably 5 minutes, and even more preferably 2 minutes.

[0081] Plasma is generated, for example, in an atmosphere of a mixed gas of H2 gas and Ar gas. In addition to H2 gas and Ar gas, a carbon-containing gas such as CF4 gas or CH4 gas may be introduced. Note that at least one of CF4 gas, NF3 gas, CHF3 gas, CO2 gas, CH2F2 gas, CH4 gas, and C4F8 gas may be introduced instead of one or both of H2 gas and Ar gas.

[0082] 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.

[0083] As the lower limit of the average thickness of the resist underlayer film to be formed, 10 nm is preferable, 20 nm is more preferable, and 30 nm is even more preferable. As the upper limit of the average thickness, 3,000 nm is preferable, 1,000 nm is more preferable, and 100 nm is even more preferable. Note that the method for measuring the average thickness is as described in the examples.

[0084] [Silicon-containing film formation step] In this step, before forming the resist pattern, a silicon-containing film is formed directly or indirectly on the resist underlayer film formed through the above coating step and, if necessary, the above 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.

[0085] The silicon-containing film can be formed by coating a composition for forming a silicon-containing film, chemical vapor deposition (CVD) method, atomic layer deposition (ALD), etc. Examples of the method for forming a silicon-containing film by coating a composition for forming a silicon-containing film include a method of curing a coating film formed by directly or indirectly coating a composition for forming a silicon-containing film on the resist underlayer film by exposure and / or heating. As commercially available products of the composition for forming a silicon-containing film, for example, "NFC SOG01", "NFC SOG04", "NFC SOG080" (above, JSR Corporation), etc. can be used. A silicon oxide film, a silicon nitride film, a silicon oxynitride film, and an amorphous silicon film can be formed by chemical vapor deposition (CVD) method or atomic layer deposition (ALD).

[0086] Examples of the radiation used for the exposure include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, X-rays, and γ-rays, and particle beams such as electron beams, molecular beams, and ion beams.

[0087] As the lower limit of the temperature when heating the coating film, 90°C is preferable, 150°C is more preferable, and 200°C is even more preferable. As the upper limit of the temperature, 550°C is preferable, 450°C is more preferable, and 300°C is even more preferable.

[0088] As the lower limit of the average thickness of the silicon-containing film, 1 nm is preferable, 10 nm is more preferable, and 20 nm is even more preferable. As the upper limit, 20,000 nm is preferable, 1,000 nm is more preferable, and 100 nm is even more preferable. The average thickness of the silicon-containing film is a value measured using the spectroscopic ellipsometer in the same manner as the average thickness of the resist underlayer film.

[0089] [Resist pattern formation step] In this step, a resist pattern is formed directly or indirectly on the resist underlayer film. Examples of the method for performing this step include a method using a resist composition, a method using a nanoimprint method, and a method using a self-assembled composition. Examples of the case where a resist pattern is formed indirectly on the resist underlayer film include a case where a resist pattern is formed on the silicon-containing film.

[0090] Examples of the resist composition include a positive or negative chemically amplified resist composition containing a radiation-sensitive acid generator, a positive resist composition containing an alkali-soluble resin and a quinonediazide-based photosensitizer, and a negative resist composition containing an alkali-soluble resin and a crosslinking agent.

[0091] First, a resist composition is applied directly or indirectly onto the above-mentioned resist underlayer film to form a resist film. Examples of the coating method of the resist composition include a spin coating method and the like. After coating, if necessary, pre-baking (PB) may be performed to promote the volatilization of the solvent in the coated film. The temperature and time of pre-baking can be appropriately adjusted according to the type of the resist composition used and the like.

[0092] Next, the resist film formed above is exposed by selective radiation irradiation. The radiation used for exposure can be appropriately selected according to the type of the radiation-sensitive acid generator used in the resist composition and the like. Examples thereof include electromagnetic waves such as visible light, ultraviolet rays, far ultraviolet rays, X-rays, and γ-rays, and particle beams such as electron beams, molecular beams, and ion beams. Among these, far ultraviolet rays are preferable, and KrF excimer laser light (wavelength 248 nm), ArF excimer laser light (wavelength 193 nm), F2 excimer laser light (wavelength 157 nm), Kr2 excimer laser light (wavelength 147 nm), ArKr excimer laser light (wavelength 134 nm), or extreme ultraviolet rays (wavelength 13.5 nm, etc., hereinafter also referred to as "EUV") are more preferable, and KrF excimer laser light, ArF excimer laser light, or EUV are even more preferable.

[0093] After the above exposure, post-baking can be performed to improve resolution, pattern profile, developability, and the like. The temperature and time of this post-baking can be appropriately determined according to the type of the resist composition used and the like.

[0094] Next, the exposed resist film is developed with a developer to form a resist pattern. This development may be either alkali development or organic solvent development. Examples of the developer include, in the case of alkali development, basic aqueous solutions such as ammonia, triethanolamine, tetramethylammonium hydroxide (TMAH), and tetraethylammonium hydroxide. Appropriate amounts of water-soluble organic solvents such as alcohols like methanol and ethanol, and surfactants can also be added to these basic aqueous solutions. In the case of organic solvent development, examples of the developer include various organic solvents exemplified as the [B] solvent of the above-described resist underlayer film-forming composition.

[0095] After development with the above developer, washing and drying are performed to form a predetermined resist pattern.

[0096] [Etching Step] In this step, etching is performed using the above resist pattern as a mask. The number of etching times can be once or multiple times, that is, sequential etching may be performed using the pattern obtained by etching as a mask. From the viewpoint of obtaining a pattern with a better shape, multiple times are preferred. When performing multiple times of etching, for example, etching is sequentially performed in the order of a silicon-containing film, a resist underlayer film, and a substrate. Examples of the etching method include dry etching and wet etching. From the viewpoint of making the shape of the pattern on the substrate better, dry etching is preferred. For this dry etching, gas plasmas such as oxygen plasma are used. By the above etching, a semiconductor substrate having a predetermined pattern is obtained.

[0097] As dry etching, for example, it can be carried out using a known dry etching apparatus. The etching gas used for dry etching can be appropriately selected according to the mask pattern, the elemental composition of the film to be etched, etc. For example, fluorine-based gases such as CHF3, CF4, C2F6, C3F8, SF6, etc., chlorine-based gases such as Cl2, BCl3, etc., oxygen-based gases such as O2, O3, H2O, etc., reducing gases such as H2, NH3, CO, CO2, CH4, C2H2, C2H4, C2H6, C3H4, C3H6, C3H8, HF, HI, HBr, HCl, NO, NH3, BCl3, etc., and inert gases such as He, N2, Ar, etc. These gases can also be used in combination. When etching the resist underlayer film, usually, an oxygen-based gas is used. When etching the substrate using the pattern of the resist underlayer film as a mask, usually, a fluorine-based gas is used.

[0098] 《Composition》 The composition contains a compound containing at least one nitrogen-containing ring structure selected from the group consisting of a pyridine ring structure and a pyrimidine ring structure, a partial structure represented by the following formula (1-1) or (1-2), and a solvent.

[0099]

Chemical formula

[0100]

Chemical formula

[0101] The above compound in the composition corresponds to the [A] compound in the above composition for forming a resist underlayer film, and the above solvent corresponds to the [B] solvent. Therefore, except for the use as a composition for forming a resist underlayer film, the above composition for forming a resist underlayer film can be preferably used as the composition.

[0102] Although the composition is preferably used for forming a resist underlayer film, it is not limited thereto and can be applied to other interlayer films, surface modification films, sealing films, etc.

Examples

[0103] Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples.

[0104] [Weight average molecular weight (Mw)] The Mw of polymer (x-1) was measured by gel permeation chromatography (detector: differential refractometer) using GPC columns of Tosoh Corporation ("G2000HXL" 2 pieces and "G3000HXL" 1 piece), flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, and column temperature: 40°C, with monodisperse polystyrene as the standard.

[0105] [Average thickness of the film] The average thickness of the film was determined as the value obtained by measuring the film thickness at any nine points at 5 cm intervals including the center of the resist underlayer film using a spectroscopic ellipsometer ("M2000D" manufactured by J.A. WOLLAM) and calculating the average value of those film thicknesses.

[0106] <[Synthesis of Compound]> According to the procedure shown below, a compound represented by the following formula (A-1) to (A-10) (hereinafter also referred to as "compounds (A-1) to (A-10)"), a polymer represented by the following formula (x-1) (hereinafter also referred to as "polymer (x-1)"), and a compound represented by the following formula (x-2) (hereinafter also referred to as "compound (x-2)") were synthesized respectively.

[0107] [Chemical Formula]

[0108] [Chemical Formula]

[0109] [Chemical Formula]

[0110] [Synthesis Example 1] (Synthesis of Compound (a-1)) Into a reaction vessel, 30.0 g of 2-acetylfluorene, 16.6 g of 1-formylpyrene, 9.26 g of benzylamine, and 28.0 g of decalin were charged under a nitrogen atmosphere and heated to 80 °C to dissolve. Next, after adding 0.69 g of diphenylammonium trifluoromethanesulfonate, it was heated to 130 °C and reacted for 20 hours. After completion of the reaction, 90 g of toluene, 60 g of water, and 180 g of hexane were added to obtain a precipitate. The obtained precipitate was collected by filter paper, washed with a tetrahydrofuran / hexane = 50 / 50 wt% solution, and dried to obtain a compound (a-1) represented by the following formula (a-1).

[0111] [Chemical Formula]

[0112] [Synthesis Example 2] (Synthesis of Compound (a-2)) In a reaction vessel, under a nitrogen atmosphere, 30.0 g of indanone, 26.1 g of 1-formylpyrene, 13.5 g of ammonium acetate, and 281 g of ethanol were charged and heated to 70 °C to dissolve. Then, after adding 1.96 g of L-proline, it was heated to 85 °C and reacted for 18 hours. After completion of the reaction, 280 g of methanol was added to obtain a precipitate. The obtained precipitate was collected by filter paper, washed with a tetrahydrofuran / hexane = 50 / 50 wt% solution, and dried to obtain Compound (a-2) represented by the following formula (a-2).

[0113] [Chemical Formula]

[0114] [Synthesis Example 3] (Synthesis of Compound (a-3)) In a reaction vessel, under a nitrogen atmosphere, 30.0 g of 2-acetylfluorene, 10.8 g of piperonal, 34.2 g of ammonium acetate, and 61.2 g of chlorobenzene were charged and heated to 100 °C to dissolve. Then, after adding 1.08 g of iodine, it was heated to 135 °C and reacted for 18 hours. After completion of the reaction, 60 g of toluene, 60 g of water, and 120 g of hexane were added to obtain a precipitate. The obtained precipitate was collected by filter paper, washed with a tetrahydrofuran / hexane = 50 / 50 wt% solution, and dried to obtain Compound (a-3) represented by the following formula (a-3).

[0115] [Chemical Formula]

[0116] [Synthesis Example 4] (Synthesis of Compound (a-4)) Into a reaction vessel, 15.0 g of indanone, 15.9 g of 3-formylperylene, 6.73 g of ammonium acetate, 92.8 g of dioxane, and 309 g of ethanol were charged under a nitrogen atmosphere, and the mixture was heated to 70 °C to dissolve. Then, after adding 1.96 g of L-proline, the mixture was heated to 85 °C and reacted for 24 hours. After completion of the reaction, 310 g of methanol was added to obtain a precipitate. The obtained precipitate was collected by filter paper, washed with a tetrahydrofuran / hexane = 50 / 50 wt% solution, and dried to obtain a compound (a-4) represented by the following formula (a-4).

[0117] [Chemical formula]

[0118] [Synthesis Example 5] (Synthesis of compound (a-5)) Into a reaction vessel, 30.0 g of indanone, 15.2 g of terephthalaldehyde, 26.9 g of ammonium acetate, and 226 g of ethanol were charged under a nitrogen atmosphere, and the mixture was heated to 70 °C to dissolve. Then, after adding 3.92 g of L-proline, the mixture was heated to 85 °C and reacted for 24 hours. After completion of the reaction, 230 g of methanol was added to obtain a precipitate. The obtained precipitate was collected by filter paper, washed with a tetrahydrofuran / hexane = 50 / 50 wt% solution, and dried to obtain a compound (a-5) represented by the following formula (a-5).

[0119] [Chemical formula]

[0120] [Synthesis Example 6] (Synthesis of compound (a-6)) Into a reaction vessel, 30.0 g of 3-acetylindole, 21.7 g of 1-formylpyrene, 44.7 g of ammonium acetate, and 77.5 g of chlorobenzene were charged under a nitrogen atmosphere, heated to 100 °C and dissolved. Then, after adding 1.41 g of iodine, the mixture was heated to 135 °C and reacted for 18 hours. After completion of the reaction, 60 g of toluene, 60 g of water, and 120 g of hexane were added to obtain a precipitate. The obtained precipitate was collected by filter paper, washed with a tetrahydrofuran / hexane = 50 / 50 wt% solution, and dried to obtain a compound (a-6) represented by the following formula (a-6).

[0121] [Chemical formula]

[0122] [Synthesis Example 7] (Synthesis of compound (a-7)) Into a reaction vessel, 15.0 g of 2-acetylfluorene, 21.4 g of piperonal, 44.7 g of ammonium iodide, and 77.5 g of chlorobenzene were charged under a nitrogen atmosphere, heated to 100 °C and dissolved. Then, after adding 1.41 g of iodine, the mixture was heated to 135 °C and reacted for 18 hours. After completion of the reaction, 60 g of toluene, 60 g of water, and 120 g of hexane were added to obtain a precipitate. The obtained precipitate was collected by filter paper, washed with a tetrahydrofuran / hexane = 50 / 50 wt% solution, and dried to obtain a compound (a-7) represented by the following formula (a-7).

[0123] [Chemical formula]

[0124] [Synthesis Example 8] (Synthesis of compound (a-8)) Into a reaction vessel, 15.0 g of 2-acetylfluorene, 33.2 g of 1-formylpyrene, 20.8 g of ammonium carbonate, and 77.5 g of chlorobenzene were charged under a nitrogen atmosphere, heated to 100 °C and dissolved. Next, after adding 1.41 g of iodine, the mixture was heated to 135 °C and reacted for 18 hours. After completion of the reaction, 60 g of toluene, 60 g of water, and 120 g of hexane were added to obtain a precipitate. The obtained precipitate was collected by filter paper, washed with a tetrahydrofuran / hexane = 50 / 50 wt% solution, and dried to obtain a compound (a-8) represented by the following formula (a-8).

[0125] [Chemical formula]

[0126] [Synthesis Example 9] (Synthesis of compound (a-9)) Into a reaction vessel, 15.0 g of 5-acetyl-1,3-benzodioxole, 35.5 g of 2-fluorene carboxaldehyde, 20.8 g of ammonium carbonate, and 77.5 g of chlorobenzene were charged under a nitrogen atmosphere, heated to 100 °C and dissolved. Next, after adding 1.41 g of iodine, the mixture was heated to 135 °C and reacted for 18 hours. After completion of the reaction, 60 g of toluene, 60 g of water, and 120 g of hexane were added to obtain a precipitate. The obtained precipitate was collected by filter paper, washed with a tetrahydrofuran / hexane = 50 / 50 wt% solution, and dried to obtain a compound (a-9) represented by the following formula (a-9).

[0127] [Chemical formula]

[0128] [Synthesis Example 10] (Synthesis of compound (a-10)) Into a reaction vessel, 15.0 g of 5-acetyl-1,3-benzodioxole, 22.3 g of acetylpyrene, 20.8 g of ammonium carbonate, and 77.5 g of chlorobenzene were charged under a nitrogen atmosphere, and the mixture was heated to 100 °C to dissolve. Then, 1.41 g of iodine was added, and the mixture was heated to 135 °C and reacted for 18 hours. After completion of the reaction, 60 g of toluene, 60 g of water, and 120 g of hexane were added to obtain a precipitate. The obtained precipitate was collected by filter paper, washed with a tetrahydrofuran / hexane = 50 / 50 wt% solution, and dried to obtain a compound (a-10) represented by the following formula (a-10).

[0129] [Chemical formula]

[0130] [Synthesis Example 11] (Synthesis of Compound (A-1)) Into a reaction vessel, 10.0 g of the above compound (a-1), 4.5 g of m-ethynylbenzaldehyde, and 43.5 g of tetrahydrofuran were added under a nitrogen atmosphere. After stirring, 43.2 g of a 25 wt% aqueous solution of tetramethylammonium hydroxide and 1.06 g of tetrabutylammonium bromide were added, and the mixture was reacted at 40 °C for 4 hours. After completion of the reaction, the aqueous phase was removed, and then 45 g of a 5 wt% aqueous oxalic acid solution and 44 g of methyl isobutyl ketone were added. After removing the aqueous phase, liquid-liquid extraction with water was performed, and the organic layer was poured into hexane for reprecipitation. The precipitate was collected by filter paper and dried to obtain Compound (A-1).

[0131] [Synthesis Example 12] (Synthesis of Compound (A-2)) Compound (A-2) was obtained in the same manner as in Synthesis Example 11, except that 7.6 g of the above compound (a-2) was used instead of 10.0 g of the above compound (a-1).

[0132] [Synthesis Example 13] (Synthesis of Compound (A-3)) Compound (A-3) was obtained in the same manner as in Synthesis Example 11, except that 8.8 g of the above compound (a-3) was used instead of 10.0 g of the above compound (a-1).

[0133] [Synthesis Example 14] (Synthesis of Compound (A-4)) In a reaction vessel, under a nitrogen atmosphere, 10.0 g of the above compound (a-4), 14.1 g of propargyl bromide, and 50 g of dioxane were added, and after stirring, 17.8 g of a 50% by mass aqueous potassium hydroxide solution and 1.28 g of tetrabutylammonium bromide were added, and the mixture was reacted at 95 °C for 12 hours. After completion of the reaction, the aqueous phase was removed, then 40 g of water and 100 g of hexane were added, and the precipitate was collected by filtration and dried to obtain Compound (A-4).

[0134] [Synthesis Example 15] (Synthesis of Compound (A-5)) Compound (A-5) was obtained in the same manner as in Synthesis Example 14, except that 6.0 g of the above compound (a-5) was used instead of 10.0 g of the above compound (a-4).

[0135] [Synthesis Example 16] (Synthesis of Compound (A-6)) Compound (A-6) was obtained in the same manner as in Synthesis Example 14, except that 20.0 g of the above compound (a-6) was used instead of 10.0 g of the above compound (a-4).

[0136] [Synthesis Example 17] (Synthesis of Compound (A-7)) In a reaction vessel, under a nitrogen atmosphere, 10.0 g of the above compound (a-7), 3.2 g of m-ethynylbenzaldehyde, and 43.5 g of tetrahydrofuran were added, and after stirring, 43.2 g of a 25% by mass aqueous tetramethylammonium hydroxide solution and 1.06 g of tetrabutylammonium bromide were added, and the mixture was reacted at 40 °C for 4 hours. After completion of the reaction, the aqueous phase was removed, then 45 g of a 5% by mass oxalic acid aqueous solution and 44 g of methyl isobutyl ketone were added. After removing the aqueous phase, liquid separation extraction with water was performed, and the organic layer was poured into hexane for reprecipitation. The precipitate was collected by filtration and dried to obtain Compound (A-7).

[0137] [Synthesis Example 18] (Synthesis of Compound (A-8)) Compound (A-8) was obtained in the same manner as in Synthesis Example 17, except that 13.3 g of the above compound (a-8) was used instead of 10.0 g of the above compound (a-7).

[0138] [Synthesis Example 19] (Synthesis of Compound (A-9)) Compound (A-9) was obtained in the same manner as in Synthesis Example 17, except that 15.6 g of the above compound (a-9) was used instead of 10.0 g of the above compound (a-7).

[0139] [Synthesis Example 20] (Synthesis of Compound (A-10)) Compound (A-10) was obtained in the same manner as in Synthesis Example 17, except that 17.3 g of the above compound (a-10) was used instead of 10.0 g of the above compound (a-7).

[0140] [Synthesis Example 21] (Synthesis of Polymer (x-1)) Into a reaction vessel, 250.0 g of m-cresol, 125.0 g of 37% by mass formalin, and 2 g of oxalic anhydride were added under a nitrogen atmosphere, and the mixture was reacted at 100 °C for 3 hours and at 180 °C for 1 hour. Then, unreacted monomers were removed under reduced pressure to obtain Polymer (x-1). The Mw of the obtained Polymer (x-1) was 11,000.

[0141] [Synthesis Example 22] (Synthesis of Compound (x-2)) Into a reaction vessel, 23.2 g of cyanuric chloride, 50.0 g of phloroglucinol, 586 g of diethyl ether, and 146 g of 1,2-dichloroethane were charged and dissolved at room temperature. After cooling to 0 °C, 52.9 g (396.5 mmol) of aluminum chloride was added to initiate the reaction. After the addition was completed, the mixture was warmed to 40 °C and reacted for 12 hours. After the reaction was completed, the reaction solution was concentrated to remove diethyl ether, and then reprecipitated with a large amount of 10% hydrochloric acid. The precipitate was dissolved in 300 g of dimethylformamide and 300 of methanol, and then reprecipitated with a large amount of 10% hydrochloric acid to recover the precipitate. The precipitate was dispersed in 500 g of ethanol, neutralized with triethylamine, and the precipitate was dried to obtain an intermediate compound.

[0142] Into a reaction vessel, 20.0 g of the above intermediate compound, 120 g of N,N-dimethylacetamide and 60.4 g of potassium carbonate were charged under a nitrogen atmosphere. Next, the mixture was heated to 60 °C, 52.9 g of allyl bromide was added, and then the reaction was carried out with stirring for 18 hours. Thereafter, 40 g of methyl isobutyl ketone, 40 g of tetrahydrofuran and 240 g of water were added to the reaction solution for liquid separation operation. Then, the organic phase was poured into a large amount of hexane, and the precipitated compound was filtered to obtain compound (x-2).

[0143] <Preparation of Composition> The [A] compound, [B] solvent, [C] acid generator and [D] crosslinking agent used in the preparation of the composition are shown below.

[0144] [[A] Compound] Examples: The above-synthesized compounds (A-1) to (A-10) Comparative Examples: The above-synthesized polymer (x-1) and compound (x-2)

[0145] [[B] Solvent] B-1: Propylene glycol monomethyl ether acetate B-2: Cyclohexanone

[0146] [[C] Acid Generator] C-1: Bis(4-t-butylphenyl)iodonium nonafluoro-n-butanesulfonate (compound represented by the following formula (C-1))

[0147] [Chemical Formula]

[0148] [[D] Crosslinking Agent] D-1: 1,3,4,6-Tetrakis(methoxymethyl)glycoluril (compound represented by the following formula (D-1))

[0149] [Chemical Formula]

[0150] [Example 1] 10 parts by mass of (A-1) as [A] compound was dissolved in 90 parts by mass of (B-1) as [B] 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).

[0151] [Examples 2 to 10 and Comparative Examples 1 to 2] Compositions (J-2) to (J-10) and (CJ-1) to (CJ-2) were prepared in the same manner as in Example 1, except that each component having the types and contents shown in Table 1 below was used. The "-" in the columns of "[C] Acid Generator" and "[D] Crosslinking Agent" in Table 1 indicates that the corresponding component was not used. The "Hydrogen Atom Content Ratio" in Table 1 indicates the content ratio of hydrogen atoms to all atoms constituting [A] compound, and is a value calculated from the molecular formula of [A] compound. The "-" in the column of "Hydrogen Atom Content Ratio" in Table 1 indicates that the hydrogen atom content ratio was not calculated.

[0152] [Table 1]

[0153] [Evaluation] Using the above-obtained compositions, evaluation was carried out on etching resistance, heat resistance, and bend resistance by the following methods. The evaluation results are shown in Table 2 below.

[0154] [Etching Resistance] The above-prepared composition was applied onto a silicon wafer (substrate) by spin coating using a spin coater ("CLEAN TRACK ACT12" manufactured by Tokyo Electron Limited). Next, after heating at 350 °C for 60 seconds in an air atmosphere and then cooling at 23 °C for 60 seconds, a film with an average thickness of 200 nm was formed, and a film-coated substrate with a film formed thereon was obtained. The film on the obtained film-coated substrate was processed using an etching apparatus ("TACTRAS" manufactured by Tokyo Electron Limited) under the conditions of CF4 / Ar = 110 / 440 sccm, PRESS. = 30 MT, HF RF (high-frequency power for plasma generation) = 500 W, LF RF (high-frequency power for bias) = 3000 W, DCS = -150 V, RDC (gas center flow rate ratio) = 50%, and for 30 seconds. The etching rate (nm / min) was calculated from the average thickness of the film before and after the treatment. Subsequently, the ratio to Comparative Example 2 was calculated based on the etching rate of Comparative Example 2, and this ratio was used as a measure of etching resistance. The etching resistance was evaluated as "A" (extremely good) when the above ratio was 0.95 or less, "B" (good) when it exceeded 0.95 and was less than 1.00, and "C" (poor) when it was 1.00 or more. Note that "-" in Table 2 indicates that it is an evaluation criterion for etching resistance.

[0155] [Heat resistance] The above-prepared composition was applied onto a silicon wafer (substrate) by spin coating using a spin coater ("CLEAN TRACK ACT12" manufactured by Tokyo Electron Limited). Next, after heating at 200 °C for 60 seconds in an air atmosphere and then cooling at 23 °C for 60 seconds, a film with an average thickness of 200 nm was formed, and a film-coated substrate with a film formed thereon was obtained. The powder was recovered by scraping the film of the obtained film-coated substrate, and the recovered powder was placed in a container used for measurement by a TG-DTA apparatus ("TG-DTA2000SR" manufactured by NETZSCH), and the mass before heating was measured. Next, using the above TG-DTA apparatus, it was heated up to 400 °C at a heating rate of 10 °C / min in a nitrogen atmosphere, and the mass of the powder when it reached 400 °C was measured. Then, the mass reduction rate (%) was measured by the following formula, and this mass reduction rate was used as a measure of heat resistance. M L={(m1 - m2) / m1}×100 Here, in the above formula, M L is the mass loss rate (%), m1 is the mass (mg) before heating, and m2 is the mass (mg) at 400°C. The heat resistance is better as the mass loss rate of the powder used as the sample is smaller, meaning there are fewer sublimates and decomposition products of the film generated during heating of the film. That is, a smaller mass loss rate indicates higher heat resistance. The heat resistance was evaluated as "A" (extremely good) when the mass loss rate was less than 5%, "B" (good) when it was 5% or more and less than 10%, and "C" (poor) when it was 10% or more.

[0156] [Bending resistance] The above-prepared composition was spin-coated onto a silicon substrate on which a silicon dioxide film with an average thickness of 500 nm was formed, using a spin coater ("CLEAN TRACK ACT12" manufactured by Tokyo Electron Limited). Next, after heating at 350°C for 60 seconds in an air atmosphere and then cooling at 23°C for 60 seconds, a substrate with a resist underlayer film having an average thickness of 200 nm was obtained. On the obtained substrate with the film, a composition for forming a silicon-containing film ("NFC SOG080" manufactured by JSR Corporation) was spin-coated, then heated at 200°C for 60 seconds in an air atmosphere and further heated at 300°C for 60 seconds to form a silicon-containing film with an average thickness of 50 nm. On the above silicon-containing film, an ArF resist composition ("AR1682J" manufactured by JSR Corporation) was spin-coated and heated (baked) at 130°C for 60 seconds in an air atmosphere to form a resist film with an average thickness of 200 nm. The resist film was exposed using an ArF excimer laser exposure apparatus (lens numerical aperture 0.78, exposure wavelength 193 nm) through a 1:1 line and space mask pattern with a target size of 100 nm while changing the exposure dose. After that, it was heated (baked) at 130°C for 60 seconds in an air atmosphere, developed at 25°C for 1 minute using a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution, washed with water, and dried to obtain a substrate on which a resist pattern of a 200 nm pitch line and space with a line width of the line pattern ranging from 30 nm to 100 nm was formed.

[0157] Using the resist pattern as a mask, with the etching apparatus, a silicon-containing film was etched under the conditions of CF4 = 200 sccm, PRESS. = 85 mT, HF RF (high-frequency power for plasma generation) = 500 W, LF RF (high-frequency power for bias) = 0 W, DCS = -150 V, RDC (gas center flow rate ratio) = 50%, to obtain a substrate with a pattern formed on the silicon-containing film. Next, using the silicon-containing film pattern as a mask, with the etching apparatus, the resist underlayer film was etched under the conditions of O2 = 400 sccm, PRESS. = 25 mT, HF RF (high-frequency power for plasma generation) = 400 W, LF RF (high-frequency power for bias) = 0 W, DCS = 0 V, RDC (gas center flow rate ratio) = 50%, to obtain a substrate with a pattern formed on the resist underlayer film. Using the resist underlayer film pattern as a mask, with the etching apparatus, a silicon dioxide film was etched under the conditions of CF4 = 180 sccm, Ar = 360 sccm, PRESS. = 150 mT, HF RF (high-frequency power for plasma generation) = 1,000 W, LF RF (high-frequency power for bias) = 1,000 W, DCS = -150 V, RDC (gas center flow rate ratio) = 50%, for 60 seconds, to obtain a substrate with a pattern formed on the silicon dioxide film.

[0158] Thereafter, for the substrate with a pattern formed on the silicon dioxide film, an image magnified 250,000 times of the shape of the resist underlayer film pattern of each line width was obtained using a scanning electron microscope ("CG-4000" of Hitachi High-Technologies Corporation), and by performing image processing on the image, as shown in FIG. 1, for the lateral side 3a of the resist underlayer film pattern 3 (line pattern) with a length of 1,000 nm, the positions Xn (n = 1 to 10) in the line width direction measured at 100 nm intervals and the 3-sigma value obtained by multiplying the standard deviation calculated from the position Xa of the average value of these positions in the line width direction by 3 were defined as LER (line edge roughness). The LER indicating the degree of bending of the resist underlayer film pattern increases as the line width of the resist underlayer film pattern becomes thinner. The bending resistance was evaluated as "A" (good) when the line width of the film pattern with an LER of 5.5 nm was less than 40.0 nm, "B" (somewhat good) when it was 40.0 nm or more and less than 45.0 nm, and "C" (poor) when it was 45.0 nm or more. Note that the degree of bending of the film pattern shown in FIG. 1 is exaggerated compared to the actual situation.

[0159]

Table 2

[0160] As can be seen from the results in Table 2, the resist underlayer film formed from the composition of the example was excellent in etching resistance, heat resistance, and bending resistance compared to the resist underlayer film formed from the composition of the comparative example.

Industrial Applicability

[0161] The composition of the present invention can form a resist underlayer film excellent in etching resistance, heat resistance, and bending resistance. The resist underlayer film of the present invention is excellent in etching resistance, heat resistance, and bending resistance. According to the method for manufacturing a semiconductor substrate of the present invention, a well-patterned substrate can be obtained. Therefore, these can be suitably used for the manufacture of semiconductor devices and the like, which are expected to further miniaturize in the future.

Explanation of Signs

[0162] 3 Resist lower layer film pattern 3a Lateral side of the resist lower layer film pattern

Claims

1. 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 applying step; A step of performing etching using the resist pattern as a mask and including, wherein the composition for forming a resist underlayer film contains a compound including at least one nitrogen-containing ring structure selected from the group consisting of a pyridine ring structure and a pyrimidine ring structure, and a partial structure represented by the following formula (1-1) or (1-2), and a solvent and, the compound has at least one selected from the group consisting of a group represented by the following formula (X-1) and a group represented by the following formula (X-2), a method for manufacturing a semiconductor substrate. 【Chemical Formula 1】 (In Formulas (1-1) and (1-2), X １ and X ２ are each independently a group represented by the following formula (i), (ii), (iii) or (iv). * is a bond with a portion other than the partial structure represented by Formula (1-1) or (1-2) in the above compound. Ar １１ and Ar １２ are each independently a substituted or unsubstituted aromatic ring having 5 to 20 ring members that forms a condensed ring structure together with two adjacent carbon atoms in Formulas (1-1) and (1-2).) [Chemical 2] (In formula (i), R １ and R ２ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms.) In formula (ii), R ３ and R ４ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. In formula (iii), R ５ is a monovalent organic group having 1 to 20 carbon atoms. In formula (iv), R ６ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms.) [Chemical Formula 3] (In the above formulas (X-1) and (X-2), R7 is each independently a divalent hydrocarbon group having 1 to 18 carbon atoms or a single bond. * is a bond with a carbon atom in the above compound.) At least one of R1 and R2 in the above formula (i), at least one of R3 and R4 in the above formula (ii), R5 in the above formula (iii), and R6 in the above (iv) are each independently a group represented by the above formula (X-1) or (X-2).)

2. The compound is represented by the following formula (2-1), (2-2) or (2-3), the method for manufacturing a semiconductor substrate according to Claim 1. 【Chemical Formula 4】 (In the above formulas (2-1), (2-2) and (2-3), X1 and X2 are each synonymous with the above formulas (1-1) and (1-2). R8, R9, R10, R11, R12, R13, R14 and R15 are each independently a monovalent organic group having 1 to 10 carbon atoms. When a plurality of R8, R9, R10, R11, R12, R13, R14 and R15 exist respectively, the plurality of R8, R9, R10, R11, R12, R13, R14 and R15 are the same as or different from each other. n1, n4, n5, n6, n7 and n8 are each independently an integer of 0 to 4, and n2 and n3 are each independently an integer of 0 to 3. k is each independently 1 or 2. Y is a k-valent organic group having 1 to 20 carbon atoms.)

3. Before forming the resist pattern, a step of heating the resist underlayer film at 250 °C or higher The method for manufacturing a semiconductor substrate according to claim 1 or 2, further comprising

4. Before forming the resist pattern, a step of forming a silicon-containing film directly or indirectly on the resist underlayer film The method for manufacturing a semiconductor substrate according to any one of claims 1 to 3, further comprising

5. A compound containing at least one nitrogen-containing ring structure selected from the group consisting of a pyridine ring structure and a pyrimidine ring structure, and a partial structure represented by the following formula (1-1) or (1-2), and a solvent containing The compound has at least one selected from the group consisting of a group represented by the following formula (X-1) and a group represented by the following formula (X-2), A composition for forming a resist underlayer film. 【Chemical Formula 5】 (In formulas (1-1) and (1-2), X １ and X ２ are each independently a group represented by the following formula (i), (ii), (iii) or (iv). * is a bond with a part other than the partial structure represented by the above formula (1-1) or (1-2) in the above compound. Ar １１ and Ar １２ are each independently a substituted or unsubstituted aromatic ring having 5 to 20 ring members that forms a condensed ring structure together with two adjacent carbon atoms in the above formulas (1-1) and (1-2).) 【Chemical Formula 6】 (In formula (i), R １ and R ２ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms.) In formula (ii), R ３ and R ４ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ４ is a monovalent organic group having 1 to 20 carbon atoms. In formula (iii), R ５ is a monovalent organic group having 1 to 20 carbon atoms. In formula (iv), R ６ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms.) 【Chemical Formula 7】 (In the above formulas (X-1) and (X-2), R7 is each independently a divalent hydrocarbon group having 1 to 18 carbon atoms or a single bond. * is a bond to a carbon atom in the above compound.) At least one of R1 and R2 in the above formula (i), at least one of R3 and R4 in the above formula (ii), R5 in the above formula (iii), and R6 in the above (iv) are each independently a group represented by the above formula (X-1) or (X-2).)

6. The composition according to claim 5, wherein the compound is represented by the following formula (2-1), (2-2) or (2-3). 【Chemical Formula 8】 (In the above formulas (2-1), (2-2) and (2-3), X １ and X ２ are synonymous with the above formulas (1-1) and (1-2), respectively. R ８ 、R ９ 、R １０ 、R １１ 、R １２ 、R １３ 、R １４ and R １５ are each independently a monovalent organic group having 1 to 10 carbon atoms. R ８ 、R ９ 、R １０ 、R １１ 、R １２ 、R １３ 、R １４ and R １５ When there are a plurality of each of R ８ 、R ９ 、R １０ 、R １１ 、R １２ 、R １３ 、R １４ and R １５ are the same as or different from each other. n １ 、n ４ 、n ５ 、n ６ 、n ７ and n ８ are each independently an integer of 0 to 4, and n ２ and n ３ are each independently an integer of 0 to 3. k is each independently 1 or 2. Y is a k-valent organic group having 1 to 20 carbon atoms.)

7. The composition according to claim 5 or 6, wherein the content ratio of hydrogen atoms to all atoms constituting the compound is 5.5% by mass or less.

Images