Semiconductor substrate manufacturing method, composition, and resist underlayer film

Abstract

The purpose of the present invention is to provide a composition, resist underlayer film, and semiconductor substrate production method that enable forming of a film having excellent etching resistance and heat resistance. A production method for a semiconductor substrate, the method comprising: a step for applying a composition for forming a resist underlayer film directly or indirectly on a substrate; a step for forming a resist pattern directly or indirectly on the resist underlayer film formed in the applying step; and a step for performing etching using the resist pattern as a mask, wherein the composition for forming the resist underlayer film contains a solvent and a compound represented by formula (1), and the molecular weight of the compound is at least 400.　[Formula 1] (in formula (1), X1 and X2 each independently represent a group having a 9 to 40-membered aromatic ring.)

Description

[Technical Field]

[0001] The present invention relates to a method for producing a semiconductor substrate, a composition, and a resist underlayer film. [Background technology]

[0002] In the manufacture of semiconductor devices, for example, a multilayer resist process is used in which a resist pattern is formed by exposing and developing a resist film laminated on a substrate via a resist underlayer film such as an organic underlayer film or a silicon-containing film. In this process, the resist underlayer film is etched using the resist pattern as a mask, and the substrate is further etched using the resulting resist underlayer film pattern as a mask, thereby forming a desired pattern on the semiconductor substrate (see, for example, JP 2004-177668 A).

[0003] Various studies have been conducted on materials used in such compositions for forming resist underlayer films (see, for example, WO 2011 / 108365). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-177668 [Patent Document 2] International Publication No. 2011 / 108365 Summary of the Invention [Problem to be solved by the invention]

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

[0006] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a method for producing a semiconductor substrate, a composition, and a resist underlayer film that form a film having excellent etching resistance and heat resistance to obtain a well-patterned semiconductor substrate. [Means for solving the problem]

[0007] In one embodiment, the present invention provides a step of directly or indirectly applying a composition for forming a resist underlayer film to a substrate; a step of forming a resist pattern directly or indirectly on the resist underlayer film formed by the coating step; a step of performing etching using the resist pattern as a mask; Equipped with The composition for forming a resist underlayer film, A compound represented by the following formula (1), Solvent and Contains The present invention relates to a method for producing a semiconductor substrate, wherein the compound has a molecular weight of 400 or more. [ka] (In formula (1), X 1 and X 2 are each independently a group having an aromatic ring having 9 to 40 ring members.

[0008] In this specification, "number of ring members" refers to the number of atoms constituting the ring of an aromatic ring structure. For example, a biphenyl ring has 12 ring members, a naphthalene ring has 10 ring members, and a fluorene ring has 13 ring members. A "fused ring structure" refers to a structure in which adjacent rings share one edge (two adjacent atoms).

[0009] In this specification, the term "hydrocarbon group" includes linear hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. This "hydrocarbon group" includes saturated and unsaturated hydrocarbon groups. The term "linear hydrocarbon group" refers to a hydrocarbon group that does not contain a ring structure and is composed only of a linear structure, and includes both linear hydrocarbon groups and branched hydrocarbon groups. The term "alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic structure as a ring structure and does not contain an aromatic ring structure, and includes both monocyclic alicyclic hydrocarbon groups and polycyclic alicyclic hydrocarbon groups (however, it does not have to be composed only of an alicyclic structure and may contain a linear structure as part of it). The term "aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure (however, it does not have to be composed only of an aromatic ring structure and may contain an alicyclic structure or a linear structure as part of it).

[0010] In another embodiment, the present invention provides A compound represented by the following formula (1), Solvent and Contains The present invention relates to a composition in which the molecular weight of the compound is 400 or more. [ka] (In formula (1), X 1 and X 2 are each independently a group having an aromatic ring with 9 to 40 ring members.

[0011] In yet another embodiment, the present invention relates to a resist underlayer film formed from the above composition. [Effects of the Invention]

[0012] The composition of the present invention can form a film having excellent etching resistance, heat resistance, and bending resistance. The resist film of the present invention has excellent etching resistance, heat resistance, and bending resistance. According to the method for producing a semiconductor substrate of the present invention, a well-patterned semiconductor substrate can be obtained. Therefore, these can be suitably used in the production of semiconductor devices, which are expected to become even more miniaturized in the future. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic plan view for explaining a method for evaluating bending resistance. DETAILED DESCRIPTION OF THE INVENTION

[0014] The composition, resist underlayer film, and semiconductor substrate manufacturing method according to each embodiment of the present invention will be described in detail below.

[0015] <Composition> The composition comprises: A compound represented by the following formula (1) (hereinafter also referred to as "compound [A]"), solvent (hereinafter also referred to as "[B] solvent") Contains The molecular weight of the compound is 400 or more. [ka] (In formula (1), X 1 and X 2 are each independently a group having an aromatic ring with 9 to 40 ring members.

[0016] The composition may contain, in addition to the compound (A) and the solvent (B), other optional components as long as the effects of the present invention are not impaired.

[0017] The composition contains the compound [A], which allows the formation of a film having excellent etching resistance, heat resistance, and bending resistance, and is therefore suitable for use in a multilayer resist process.

[0018] Each component contained in the composition will be described below.

[0019] <[A] Compound> The compound [A] has a structure represented by the following formula (1): The composition can contain one or more types of the compound [A]. [ka] (In formula (1), X 1 and X 2 are each independently a group having an aromatic ring having 9 to 40 ring members.

[0020] In the above formula (1), X 1 and X 2 Examples of the aromatic ring having 9 to 40 ring members in the formula (I) include aromatic hydrocarbon rings such as a naphthalene ring, an anthracene ring, a phenanthrene ring, a tetracene ring, a pyrene ring, a pentacene ring, a coronene ring, a perylene ring, a fluorene ring, a biphenyl ring, a terphenyl ring, a tetraphenylbenzene ring, a pentaphenylbenzene ring, and a hexaphenylbenzene ring; and aromatic heterocycles such as a benzofuran ring, a benzothiophene ring, an indole ring, a benzimidazole ring, and a benzoxazole ring.

[0021] X 1 and X 2 The aromatic ring having 9 to 40 ring members in X may have a substituent. 1 and X 2Examples of the substituent on the aromatic ring having 9 to 40 ring members in the formula (I) include a monovalent chain hydrocarbon group having 1 to 10 carbon atoms, a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, an alkoxy group such as a methoxy group, an ethoxy group, or a propoxy group, an alkoxycarbonyl group such as a methoxycarbonyl group or an ethoxycarbonyl group, an alkoxycarbonyloxy group such as a methoxycarbonyloxy group or an ethoxycarbonyloxy group, an acyl group such as a formyl group, an acetyl group, a propionyl group, or a butyryl group, a cyano group, and a nitro group.

[0022] X 1 and X 2 At least one of the above is preferably a group represented by the following formula (1-1), (1-2) or (1-3). [ka] (In the above formula (1-1), Ar 1 and Ar 2 are each independently a substituted or unsubstituted aromatic ring having 6 to 20 ring members that forms a fused ring structure together with the cyclopentane ring in the above formula (1-1). R 1 is a monovalent organic group having 1 to 30 carbon atoms. * represents a bond to the carbon atom in the above formula (1). (In the above formula (1-2), Ar 3 and Ar 4 are each independently a substituted or unsubstituted aromatic ring having 6 to 20 ring members that forms a fused ring structure together with the cyclopentane ring in the above formula (1-2). R 2 is a substituted or unsubstituted divalent aromatic ring group having 6 to 30 ring members. * represents a bond to the carbon atom in the above formula (1). (In the above formula (1-3), Ar 5 and Ar 6 are each independently a substituted or unsubstituted aromatic ring having 6 to 20 ring members that forms a fused ring structure together with the cyclopentane ring in the above formula (1-3). R 3 and R 4 are each independently a monovalent organic group having 1 to 30 carbon atoms. * represents a bond to the carbon atom in the above formula (1).

[0023] In the above formulas (1-1), (1-2), and (1-3), Ar 1 ~Ar 6 Examples of the aromatic ring having 6 to 20 ring members in the formula (I) include aromatic hydrocarbon rings such as a benzene ring, a naphthalene ring, an anthracene ring, an indene ring, a pyrene ring, and a fluorene ring, and aromatic heterocycles such as a furan ring, a pyrrole ring, a thiophene ring, a phosphole ring, a pyrazole ring, an oxazole ring, an isoxazole ring, a thiazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, and a pyridazine ring.

[0024] Ar 1 ~Ar 6 The substituents in the above X 1 and X 2 Examples of the substituents include the same substituents as those of the aromatic ring having 9 to 40 ring members in the above.

[0025] In the above formula (1-1), R 1 Examples of the monovalent organic group having 1 to 30 carbon atoms in the formula (I) include a monovalent hydrocarbon group having 1 to 20 carbon atoms, a group having a divalent heteroatom-containing group between carbon atoms of the hydrocarbon group or at the carbon chain terminal, a group in which some or all of the hydrogen atoms of the hydrocarbon group have been substituted with a monovalent heteroatom-containing group, or a combination thereof.

[0026] Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and combinations thereof.

[0027] Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include groups in which one hydrogen atom has been removed from a linear or branched saturated or unsaturated hydrocarbon such as methane, ethane, propane, butane, hexane, or octane.

[0028] Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms include groups in which one hydrogen atom has been removed from cycloalkanes such as cyclopentane and cyclohexane, alicyclic saturated hydrocarbons such as bridged ring saturated hydrocarbons such as norbornane and adamantane, cycloalkenes such as cyclopentene and cyclohexene, and bridged ring unsaturated hydrocarbons such as norbornene.

[0029] The monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms includes the Ar 1 ~Ar 6 Examples include a group in which one hydrogen atom has been removed from an aromatic ring having 6 to 20 ring members.

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

[0031] Examples of the divalent heteroatom-containing group include -CO-, -CS-, -NH-, -O-, -S-, and combinations of these groups.

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

[0033] In the above formula (1-2), R 2 Examples of the divalent aromatic ring group having 6 to 30 ring members in the formula (I) include groups in which two hydrogen atoms have been removed from an aromatic hydrocarbon ring such as a benzene ring, a naphthalene ring, an anthracene ring, an indene ring, a pyrene ring, or a fluorene ring, or an aromatic heterocycle such as a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, or a triazine ring.

[0034] In the above formula (1-3), R 3 and R 4 In the above, the monovalent organic group having 1 to 30 carbon atoms is 1 Examples of the organic group include the same monovalent organic group having 1 to 30 carbon atoms as in the above.

[0035] In the above formulas (1-1), (1-2), and (1-3), * represents a bond to a carbon atom in the above formula (1-1), (1-2), or (1-3), respectively.

[0036] The compound [A] preferably has at least one group represented by the following formula (2-1) or (2-2). [ka] (In the above formulas (2-1) and (2-2), R 5 is a divalent hydrocarbon group having 1 to 20 carbon atoms or a single bond. * is a bond to the carbon atom in the above formula (1).

[0037] In the above formulas (2-1) and (2-2), R 5 Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms as R 1 Examples include groups in which one hydrogen atom has been removed from the examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the following formula:

[0038] Among them, R 5 is preferably a methanediyl group, a phenylene group, a combination thereof, or a single bond.

[0039] The compound [A] more preferably has at least one group represented by the above formula (2-1).

[0040] The upper limit of the content of hydrogen atoms relative to all atoms constituting the compound [A] is preferably 7% by mass, more preferably 6% by mass, and even more preferably 5% by mass. The lower limit of the content is, for example, 0.1% by mass. By setting the content of hydrogen atoms relative to all atoms constituting the compound [A] within the above range, the bending resistance of the resist underlayer film formed from the composition can be further improved. The content of hydrogen atoms relative to all atoms constituting the compound [A] is a value calculated from the molecular formula of the compound [A].

[0041] Examples of the compound [A] include compounds represented by the following formulas (A-1) to (A-5).

[0042] [ka]

[0043] The lower limit of the molecular weight of the compound [A] is preferably 400, more preferably 500, even more preferably 550, and particularly preferably 600. The upper limit of the molecular weight is preferably 3,000, more preferably 1,500, and even more preferably 1,000. By setting the molecular weight of the compound [A] within the above range, the flatness of the resist underlayer film formed from the composition can be further improved.

[0044] The upper limit of the content of hydrogen atoms relative to all atoms constituting the compound [A] is preferably 7% by mass, more preferably 6% by mass, and even more preferably 5% by mass. The lower limit of the content is, for example, 0.1% by mass. By setting the content of hydrogen atoms relative to all atoms constituting the compound [A] within the above range, the bending resistance of the resist underlayer film formed from the composition can be further improved. The content of hydrogen atoms relative to all atoms constituting the compound [A] is a value calculated from the molecular formula of the compound [A].

[0045] The lower limit of the content of the compound [A] is preferably 50 mass %, more preferably 60 mass %, and even more preferably 70 mass %, based on all components other than the solvent [B] in the composition. The upper limit of the content is preferably 100 mass % (containing only the compound [A] as a component other than the solvent [B]), and may be less than 100 mass %.

[0046] The lower limit of the content of the compound [A] in the composition is preferably 2% by mass, more preferably 4% by mass, even more preferably 5% by mass, and particularly preferably 6% by mass, based on the total mass of the compound [A] and the solvent [B]. The upper limit of the content is preferably 30% by mass, more preferably 25% by mass, even more preferably 20% by mass, and particularly preferably 18% by mass, based on the total mass of the compound [A] and the solvent [B].

[0047] [Method for synthesizing compound A] The compound [A] can be synthesized, for example, by reacting a compound containing a diyne structure, such as 1,4-bis(2-fluorenyl)-1,3-butadiyne, with an aldehyde compound, such as 4-ethynylbenzaldehyde.

[0048] <[B] Solvent> The solvent (B) is not particularly limited as long as it can dissolve or disperse the compound (A) and any optional components contained as needed.

[0049] Examples of the solvent [B] include hydrocarbon solvents, ester solvents, alcohol solvents, ketone solvents, ether solvents, nitrogen-containing solvents, etc. The solvent [B] can be used alone or in combination of two or more.

[0050] Examples of hydrocarbon solvents include aliphatic hydrocarbon solvents such as n-pentane, n-hexane, and cyclohexane, and aromatic hydrocarbon solvents such as benzene, toluene, and xylene.

[0051] Examples of ester-based solvents include carbonate-based solvents such as diethyl carbonate, acetate monoester-based solvents such as methyl acetate and ethyl acetate, lactone-based solvents such as γ-butyrolactone, polyhydric alcohol partial ether carboxylate-based solvents such as diethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate, and lactate-based solvents such as methyl lactate and ethyl lactate.

[0052] Examples of alcohol solvents include monoalcohol solvents such as methanol, ethanol, and n-propanol, and polyalcohol solvents such as ethylene glycol and 1,2-propylene glycol.

[0053] Examples of the ketone solvent include chain ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, and cyclic ketone solvents such as cyclohexanone.

[0054] Examples of ether solvents include chain ether solvents such as n-butyl ether, polyhydric alcohol ether solvents such as cyclic ether solvents such as tetrahydrofuran, and polyhydric alcohol partial ether solvents such as diethylene glycol monomethyl ether.

[0055] Examples of nitrogen-containing solvents include chain nitrogen-containing solvents such as N,N-dimethylacetamide, and cyclic nitrogen-containing solvents such as N-methylpyrrolidone.

[0056] The solvent (B) is preferably an ester solvent or a ketone solvent, more preferably a polyhydric alcohol partial ether carboxylate solvent or a cyclic ketone solvent, and even more preferably propylene glycol monomethyl ether acetate or cyclohexanone.

[0057] The lower limit of the content of the solvent [B] in the composition is preferably 50% by mass, more preferably 60% by mass, and even more preferably 70% by mass, and the upper limit of the content is preferably 99.9% by mass, more preferably 99% by mass, and even more preferably 95% by mass.

[0058] [Optional ingredients] The composition may contain optional components within the range that does not impair the effects of the present invention. Examples of optional components include an acid generator, a crosslinking agent, a surfactant, etc. The optional components may be used alone or in combination of two or more. The content ratio of the optional components in the composition can be appropriately determined depending on the type of optional component, etc.

[0059] The composition is particularly preferably used for forming a resist underlayer film, since it can form a film that has excellent etching resistance, heat resistance, and bending resistance.

[0060] [Method for preparing the composition] The composition can be prepared by mixing the compound [A], the solvent [B], and, if necessary, any optional components in a predetermined ratio, and then filtering the resulting mixture preferably through a membrane filter or the like having a pore size of 0.45 μm or less.

[0061] <Resist Underlayer Film> The resist underlayer film is a film formed from the above-mentioned composition.

[0062] The resist underlayer film is formed from the above-described composition, and therefore has excellent etching resistance, heat resistance, and bending resistance. The method for forming the resist underlayer film will be described in detail in the next section on the method for manufacturing a semiconductor substrate.

[0063] <Method of manufacturing semiconductor substrate> The method for manufacturing the semiconductor substrate includes: a step of directly or indirectly applying a composition for forming a resist underlayer film to a substrate (hereinafter also referred to as a "coating step"); a step of directly or indirectly forming a resist pattern on the resist underlayer film formed in the coating step (hereinafter also referred to as a "resist pattern forming step"); The method includes a step of performing etching using the resist pattern as a mask (hereinafter also referred to as "etching step").

[0064] According to the method for producing a semiconductor substrate, by using the composition described above as a composition for forming a resist underlayer film in the coating step, a resist underlayer film having excellent etching resistance, heat resistance, and bending resistance can be formed, and therefore a semiconductor substrate having a good pattern shape can be produced.

[0065] The method for manufacturing a semiconductor substrate may further include, as necessary, a step of heating the resist underlayer film formed in the coating step at 200°C or higher (hereinafter also referred to as a "heating step") before the resist pattern forming step.

[0066] The method for producing a semiconductor substrate may further include, as necessary, a step of forming a silicon-containing film directly or indirectly on the resist underlayer film formed by the coating step or the heating step (hereinafter also referred to as a "silicon-containing film forming step").

[0067] The composition used in the method for producing a semiconductor substrate and each step will be described below.

[0068] [Coating process] In this step, the composition for forming a resist underlayer film is applied directly or indirectly to a substrate. In this step, the composition for forming a resist underlayer film is the composition described above.

[0069] The method for applying the composition for forming a resist underlayer film is not particularly limited, and can be any appropriate method such as spin coating, casting coating, roll coating, etc. This forms a coating film, and the resist underlayer film is formed by volatilization of the solvent [B].

[0070] Examples of the substrate include metal or semimetal substrates such as silicon substrates, aluminum substrates, nickel substrates, chromium substrates, molybdenum substrates, tungsten substrates, copper substrates, tantalum substrates, and titanium substrates, among which silicon substrates are preferred.The substrate may also be a substrate on which a silicon nitride film, an alumina film, a silicon dioxide film, a tantalum nitride film, a titanium nitride film, or the like is formed.

[0071] An example of the case where the composition for forming a resist underlayer film is indirectly applied to a substrate is the case where the composition for forming a resist underlayer film is applied onto a silicon-containing film, which will be described later, formed on the substrate.

[0072] [Heating process] In this step, the coating film formed in the coating step is heated. Heating the coating film promotes the formation of the resist underlayer film. More specifically, heating the coating film promotes the evaporation of the solvent [B].

[0073] The coating film may be heated in an air atmosphere or a nitrogen atmosphere. The lower limit of the heating temperature is preferably 200°C, more preferably 230°C, and even more preferably 250°C. The upper limit of the heating temperature is preferably 600°C, and more preferably 500°C. The lower limit of the heating time is preferably 15 seconds, and more preferably 30 seconds. The upper limit of the heating time is preferably 1,200 seconds, and more preferably 600 seconds.

[0074] The lower limit of the average thickness of the resist underlayer film formed is preferably 10 nm, more preferably 20 nm, and even more preferably 30 nm. The upper limit of the average thickness is preferably 3,000 nm, more preferably 1,000 nm, and even more preferably 100 nm. The average thickness is measured as described in the Examples.

[0075] [Silicon-containing film formation process] In this process, a silicon-containing film is formed directly or indirectly on the resist underlayer film formed by the coating process or the heating process.When the silicon-containing film is formed indirectly on the resist underlayer film, for example, a surface-modified film of the resist underlayer film is formed on the resist underlayer film.The surface-modified film of the resist underlayer film is, for example, a film whose contact angle with water is different from that of the resist underlayer film.

[0076] The silicon-containing film can be formed by coating a silicon-containing film-forming composition, chemical vapor deposition (CVD), atomic layer deposition (ALD), or the like. Examples of methods for forming a silicon-containing film by coating a silicon-containing film-forming composition include a method in which the silicon-containing film-forming composition is directly or indirectly coated onto the resist underlayer film, and the resulting coated film is then cured by exposure and / or heating. Examples of commercially available silicon-containing film-forming compositions that can be used include "NFC SOG01," "NFC SOG04," and "NFC SOG080" (all from JSR Corporation). Silicon oxide films, silicon nitride films, silicon oxynitride films, and amorphous silicon films can be formed by chemical vapor deposition (CVD) or atomic layer deposition (ALD).

[0077] Examples of 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.

[0078] The lower limit of the temperature when heating the coating film is preferably 90°C, more preferably 150°C, and even more preferably 200°C. The upper limit of the temperature is preferably 550°C, more preferably 450°C, and even more preferably 300°C.

[0079] The lower limit of the average thickness of the silicon-containing film is preferably 1 nm, more preferably 10 nm, and even more preferably 20 nm. The upper limit is preferably 20,000 nm, more preferably 1,000 nm, and even more preferably 100 nm. The average thickness of the silicon-containing film is a value measured using the spectroscopic ellipsometer, similar to the average thickness of the resist underlayer film.

[0080] [Resist pattern formation process] In this step, a resist pattern is formed directly or indirectly on the resist underlayer film.Methods for carrying out this step include, for example, a method using a resist composition, a method using a nanoimprint method, a method using a self-assembling composition, etc.An example of a case where a resist pattern is formed indirectly on the resist underlayer film is, for example, a case where a resist pattern is formed on the silicon-containing film.

[0081] Examples of the resist composition include a positive or negative chemically amplified resist composition that contains a radiation-sensitive acid generator, a positive resist composition that contains an alkali-soluble resin and a quinone diazide-based photosensitizer, and a negative resist composition that contains an alkali-soluble resin and a crosslinking agent.

[0082] The resist composition can be applied, for example, by rotary coating, etc. The pre-baking temperature and time can be adjusted appropriately depending on the type of resist composition used.

[0083] Next, the resist film formed above is exposed by selective irradiation with radiation. The radiation used for exposure can be appropriately selected depending on the type of radiation-sensitive acid generator used in the resist composition, and examples include visible light, ultraviolet light, far ultraviolet light, electromagnetic waves such as X-rays and gamma rays, and particle beams such as electron beams, molecular beams, and ion beams. Among these, far ultraviolet light is preferred, and KrF excimer laser light (wavelength 248 nm), ArF excimer laser light (wavelength 193 nm), F2 excimer laser light (wavelength 157 nm), Kr2 excimer laser light (wavelength 147 nm), ArKr excimer laser light (wavelength 134 nm), or extreme ultraviolet light (wavelength 13.5 nm, etc., hereinafter also referred to as "EUV") is more preferred, and KrF excimer laser light, ArF excimer laser light, or EUV is even more preferred.

[0084] After the exposure, post-baking can be carried out to improve resolution, pattern profile, developability, etc. The temperature and time of this post-baking can be appropriately determined depending on the type of resist composition used, etc.

[0085] Next, the exposed resist film is developed with a developer to form a resist pattern. This development may be alkaline development or organic solvent development. In the case of alkaline development, examples of the developer include aqueous solutions of basic compounds such as ammonia, triethanolamine, tetramethylammonium hydroxide (TMAH), and tetraethylammonium hydroxide. These aqueous solutions of basic compounds may also contain an appropriate amount of a water-soluble organic solvent, such as an alcohol (e.g., methanol or ethanol), a surfactant, etc. In the case of organic solvent development, examples of the developer include the various organic solvents exemplified above as the solvent [B] of the composition.

[0086] After development with the developer, the resist is washed and dried to form a desired resist pattern.

[0087] [Etching process] In this step, etching is performed using the resist pattern as a mask. The etching may be performed once or multiple times, i.e., sequentially using the pattern obtained by etching as a mask. From the viewpoint of obtaining a pattern with a better shape, multiple times is preferred. When performing multiple etchings, for example, etching is performed sequentially in the order of the silicon-containing film, the resist underlayer film, and the substrate. Examples of etching methods include dry etching and wet etching. From the viewpoint of obtaining a better pattern shape on the substrate, dry etching is preferred. For this dry etching, a gas plasma such as oxygen plasma is used. By the above etching, a semiconductor substrate having a predetermined pattern is obtained.

[0088] Dry etching can be performed using, for example, a known dry etching apparatus. The etching gas used for dry etching can be appropriately selected depending on the mask pattern, the elemental composition of the film to be etched, etc., and includes, for example, fluorine-based gases such as CHF3, CF4, C2F6, C3F8, and SF6; chlorine-based gases such as Cl2 and BCl3; oxygen-based gases such as O2, O3, and H2O; reducing gases such as H2, NH3, CO, CO2, CH4, C2H2, C2H4, C2H6, C3H4, C3H6, C3H8, HF, HI, HBr, HCl, NO, NH3, and BCl3; and inert gases such as He, N2, and Ar. These gases can also be used in combination. When etching a substrate using a resist underlayer film pattern as a mask, a fluorine-based gas is usually used. [Example]

[0089] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples.

[0090] [Weight average molecular weight (Mw)] The Mw of polymer (a-1) was measured by gel permeation chromatography (detector: differential refractometer) using GPC columns (two "G2000HXL" and one "G3000HXL" manufactured by Tosoh Corporation) under the analytical conditions of a flow rate of 1.0 mL / min, elution solvent: tetrahydrofuran, and column temperature: 40°C, with monodisperse polystyrene as the standard.

[0091] [Average film thickness] The average thickness of the film was determined by measuring the film thickness at nine arbitrary positions at 5 cm intervals, including the center of the resist underlayer film, using a spectroscopic ellipsometer (JAWOOLLAM's "M2000D") and calculating the average of these film thicknesses.

[0092] <Synthesis of Compound [A]> According to the procedures shown below, compounds represented by the following formulas (A-1) to (A-5) (hereinafter also referred to as "compounds (A-1) to (A-5)") and a compound represented by the following formula (a-1) (hereinafter also referred to as "polymer (a-1)") were synthesized.

[0093] [ka] [ka]

[0094] [Synthesis Example 1] (Synthesis of Compound (A-1)) In a nitrogen atmosphere, 1.2 g of 1,4-bis(2-fluorenyl)-1,3-butadiyne, 0.2 g of tetrabutylammonium bromide, 8.4 g of 50% by mass aqueous tetramethylammonium hydroxide solution, and 8 g of tetrahydrofuran (hereinafter also referred to as "THF") were added to a reaction vessel and heated to 40°C. After reacting at 40°C for 0.25 hours, 0.9 g of 4-ethynylbenzaldehyde was added and reacted at 40°C for 4 hours. The reaction solution was cooled to room temperature, and 20 g of methyl isobutyl ketone was added. 50 g of a 5% by mass aqueous oxalic acid solution was added, and extraction was performed. Compound (A-1) (molecular weight 603) was obtained by reprecipitation in methanol.

[0095] [Synthesis Example 2] (Synthesis of Compound (A-2)) Compound (A-2) (molecular weight 603) was obtained in the same manner as in Synthesis Example 1, except that 3-ethynylbenzaldehyde was used instead of 4-ethynylbenzaldehyde.

[0096] [Synthesis Example 3] (Synthesis of Compound (A-3)) Compound (A-3) (molecular weight: 883) was obtained in the same manner as in Synthesis Example 1, except that 9,9-dipropargylfluorene-2-carboxaldehyde was used instead of 4-ethynylbenzaldehyde. 9,9-Dipropargylfluorene-2-carboxaldehyde was synthesized by the following method. Under a nitrogen atmosphere, 5.0 g of fluorene-2-carboxaldehyde, 0.8 g of tetrabutylammonium bromide, 12.4 g of 50% by mass aqueous sodium hydroxide solution, and 21 g of THF were added to a reaction vessel, followed by dropwise addition of 9.2 g of propargyl bromide. After completion of the dropwise addition, the mixture was allowed to react at 90°C for 5 hours. The reaction solution was cooled to room temperature, and then 20 g of methyl isobutyl ketone was added. The aqueous layer was acidified by adding a 5% by mass aqueous oxalic acid solution. After separation and extraction, the mixture was reprecipitated in hexane to obtain 9,9-dipropargylfluorene-2-carboxaldehyde.

[0097] [Synthesis Example 4] (Synthesis of Compound (A-4)) Compound (A-4) (molecular weight 655) was obtained in the same manner as in Synthesis Example 1, except that 1-naphthaldehyde was used instead of 4-ethynylbenzaldehyde.

[0098] [Synthesis Example 6] (Synthesis of Compound (A-5)) Compound (A-6) (molecular weight 651) was obtained in the same manner as in Synthesis Example 1, except that 2,7-diethynylfluorene was used instead of 1,4-bis(2-fluorenyl)-1,3-butadiyne and 1,4-bis(3-formylphenyl)-1,3-butadiyne was used instead of 4-ethynylbenzaldehyde.

[0099] Comparative Synthesis Example 1 (Synthesis of Polymer (a-1)) In a reaction vessel, 250.0 g of m-cresol, 125.0 g of 37% by mass formalin, and 2 g of anhydrous oxalic acid were added under a nitrogen atmosphere, and the mixture was reacted at 100°C for 3 hours and at 180°C for 1 hour. After that, unreacted monomers were removed under reduced pressure to obtain polymer (a-1). The Mw of the obtained compound (a-1) was 11,000.

[0100] <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.

[0101] [[A] compound] Example: Compounds (A-1) to (A-5) synthesized above Comparative Example: Polymer (a-1) synthesized above

[0102] [[B] Solvent] B-1: Cyclohexanone

[0103] [[C] Acid generator] C-1: bis(4-t-butylphenyl)iodonium nonafluoro-n-butanesulfonate (compound represented by the following formula (C-1))

[0104] [ka]

[0105] [[D] Crosslinker] D-1: 1,3,4,6-tetrakis(methoxymethyl)glycoluril (a compound represented by the following formula (D-1))

[0106] [ka]

[0107] [Example 1] 10 parts by mass of (A-1) as the compound [A] was dissolved in 90 parts by mass of (B-1) as the solvent [B]. The resulting solution was filtered through a polytetrafluoroethylene (PTFE) membrane filter with a pore size of 0.45 μm to prepare a composition for forming a resist underlayer film (J-1).

[0108] [Examples 2 to 5 and Comparative Example 1] Compositions (J-2) to (J-5) and (CJ-1) were prepared in the same manner as in Example 1, except that the types and amounts of each component shown in Table 1 below were used. In Table 1, a "-" in the "Acid Generator (C)" and "Crosslinker (D)" columns indicates that the corresponding component was not used. In Table 1, the "Hydrogen Atom Content" column indicates the hydrogen atom content ratio relative to all atoms constituting the compound (A), and is a value calculated from the molecular formula of the compound (A). In Table 1, a "-" in the "Hydrogen Atom Content" column indicates that the hydrogen atom content ratio was not calculated.

[0109] [Table 1]

[0110] <Film formation> The composition prepared above was applied onto a silicon wafer (substrate) by spin coating using a spin coater (Tokyo Electron Ltd.'s "CLEAN TRACK ACT12"), followed by heating at 350°C for 60 seconds in an air atmosphere and then cooling at 23°C for 60 seconds to form a film with an average thickness of 100 nm, yielding a film-coated substrate on which a film had been formed.

[0111] <Evaluation> The etching resistance, heat resistance, and bending resistance of the obtained compositions were evaluated by the following methods. The evaluation results are shown in Table 2 below.

[0112] [Etching resistance] The composition prepared above was applied to a silicon wafer (substrate) by spin coating using a spin coater (Tokyo Electron Limited's "CLEAN TRACK ACT12"). Next, the substrate was heated at 350°C for 60 seconds in an air atmosphere, followed by cooling at 23°C for 60 seconds to form a film with an average thickness of 100 nm, yielding a film-coated substrate. The film on the obtained film-coated substrate was treated using an etching device (Tokyo Electron Limited's "TACTRAS") under the following conditions: 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 ratio) = 50%, for 30 seconds. The etching rate (nm / min) was calculated from the average film thickness before and after treatment. Next, the ratio to the etching rate of Comparative Example 1 was calculated using the etching rate of Comparative Example 1 as a standard, and this ratio was used as a measure of etching resistance. The etching resistance was evaluated as "A" (good) when the ratio was less than 1.00, and as "B" (poor) when the ratio was 1.00 or more. In Table 2, "-" indicates that this is the evaluation standard for etching resistance.

[0113] [Heat resistance] The powders obtained in the above synthesis examples were vacuum dried. The mass change of these powders was measured using a TG-DTA device (NETZSCH "TG-DTA2000SR") under a nitrogen atmosphere while heating them to 400°C at a heating rate of 10°C / min. The mass loss rate (%) was then calculated using the following formula, and this mass loss rate was used as a measure of heat resistance. M L ={(m1-m2) / m1}×100 In the above formula, M L is the mass loss rate (%), m1 is the mass (mg) at 200°C, and m2 is the mass (mg) at 400°C.

[0114] The smaller the mass loss rate of the sample powder, the less sublimate and film decomposition products are generated when the film is heated, and the better the heat resistance. In other words, the smaller the mass loss rate, the higher the heat resistance. Heat resistance was evaluated as "A" (good) when the mass loss rate was less than 5%, and "B" (poor) when it was 5% or more.

[0115] [Bending resistance] The composition prepared above was applied by spin coating using a spin coater (Tokyo Electron Limited's "CLEAN TRACK ACT12") onto a silicon substrate on which a silicon dioxide film with an average thickness of 100 nm had been formed. The substrate was then heated at 350°C for 60 seconds in an atmospheric environment, followed by cooling at 23°C for 60 seconds, to obtain a substrate with a resist underlayer film with an average thickness of 45 nm. A silicon-containing film-forming composition (JSR Corporation's "NFC SOG080") was applied by spin coating onto the obtained substrate with a resist underlayer film, followed by heating at 200°C for 60 seconds in an atmospheric environment, followed by further heating at 300°C for 60 seconds, to form a silicon-containing film with an average thickness of 50 nm. An ArF resist composition (JSR Corporation's "AR1682J") was applied onto the silicon-containing film by spin coating 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 to light using an ArF excimer laser exposure device (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, varying the exposure dose, and then heated (baked) at 130°C for 60 seconds in an air atmosphere. The resist film was then developed using a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) at 25°C for 1 minute, washed with water, and dried to obtain a substrate on which a line-and-space resist pattern with a 200 nm pitch and line width of 25 to 50 nm was formed.

[0116] Using the resist pattern as a mask, the silicon-containing film was etched using the etching system under the following conditions: CF4 = 200 sccm, PRESS = 85 mT, HF RF (plasma generation high frequency power) = 500 W, LF RF (bias high frequency power) = 0 W, DCS = -150 V, RDC (gas center flow ratio) = 50%, to obtain a substrate with a pattern formed in the silicon-containing film. Next, using the silicon-containing film pattern as a mask, the resist underlayer film was etched using the etching system under the following conditions: O2 = 400 sccm, PRESS = 25 mT, HF RF (plasma generation high frequency power) = 400 W, LF RF (bias high frequency power) = 0 W, DCS = 0 V, RDC (gas center flow ratio) = 50%, to obtain a substrate with a pattern formed in the resist underlayer film. Using the resist underlayer film pattern as a mask, the silicon dioxide film was etched using the above etching apparatus under the following conditions: CH2CF2=30sccm, Ar=400sccm, PRESS.=45mT, HF RF (high frequency power for plasma generation)=600W, LF RF (high frequency power for bias)=3,000W, DCS=-150V, RDC (gas center flow ratio)=50%, for 60 seconds, to obtain a substrate with a pattern formed in the silicon dioxide film.

[0117] Then, for the substrate with the pattern formed on the silicon dioxide film, images of the resist underlayer film pattern for each line width were obtained at 250,000x magnification using a scanning electron microscope (Hitachi High-Technologies Corporation's "CG-4000"), and the images were processed to obtain the LER (line edge roughness) value. Ten line width position Xn (n = 1 to 10) measurements were taken at 100 nm intervals for the lateral side 3a of the 1,000 nm long resist underlayer film pattern 3 (line pattern), as shown in Figure 1. The standard deviation calculated from the average position Xa of these line width position measurements was tripled to obtain the LER (line edge roughness) value. The LER, which indicates the degree of curvature of the resist underlayer film pattern, increases as the line width of the resist underlayer film pattern narrows. The bending resistance was evaluated as "A" (good) when the line width of the resist underlayer film pattern, which resulted in an LER of 4.0 nm, was less than 34.0 nm, and as "B" (poor) when it was 34.0 nm or more. Note that the degree of bending of the resist underlayer film pattern shown in Figure 1 is exaggerated compared to the actual state.

[0118] [Table 2]

[0119] As can be seen from the results in Table 2, the resist underlayer films formed from the compositions of the examples were superior in etching resistance, heat resistance, and bending resistance compared to the resist underlayer films formed from the compositions of the comparative examples. [Industrial Applicability]

[0120] The composition of the present invention can form a resist underlayer film having excellent etching resistance, heat resistance, and bending resistance. The resist underlayer film of the present invention has excellent etching resistance, heat resistance, and bending resistance. The method for producing a semiconductor substrate of the present invention can obtain a well-patterned semiconductor substrate. Therefore, these can be suitably used in the production of semiconductor devices, which are expected to become even more miniaturized in the future. [Explanation of symbols]

[0121] 3. Resist underlayer film pattern 3a Lateral side of resist underlayer film pattern

Claims

1. a step of directly or indirectly applying a composition for forming a resist underlayer film to a substrate; a step of forming a resist pattern directly or indirectly on the resist underlayer film formed by the coating step; a step of performing etching using the resist pattern as a mask; Equipped with The composition for forming a resist underlayer film, A compound represented by the following formula (1), Solvent and Contains The method for producing a semiconductor substrate, wherein the compound has a molecular weight of 400 or more. 【Chemistry 1】 (In formula (1), X １ and X ２ are each independently a group having an aromatic ring with 9 to 40 ring members. At least one of X 1 and X 2 is a group represented by the following formula (1-1), (1-2) or (1-3). 【Chemistry 2】 (In the above formula (1-1), Ar 1 and Ar 2 each independently represent a substituted or unsubstituted aromatic ring having 6 to 20 ring members that forms a fused ring structure together with the cyclopentane ring in the above formula (1-1). R 1 is a monovalent organic group having 1 to 30 carbon atoms. * represents a bond to the carbon atom in the above formula (1). (In the above formula (1-2), Ar 3 and Ar 4 are each independently a substituted or unsubstituted aromatic ring having 6 to 20 ring members that forms a fused ring structure together with the cyclopentane ring in the above formula (1-2). R 2 is a substituted or unsubstituted divalent aromatic ring group having 6 to 30 ring members. * represents a bond to the carbon atom in the above formula (1). (In the above formula (1-3), Ar 5 and Ar 6 are each independently a substituted or unsubstituted aromatic ring having 6 to 20 ring members that forms a fused ring structure together with the cyclopentane ring in the above formula (1-3). R 3 and R 4 are each independently a monovalent organic group having 1 to 30 carbon atoms. * represents a bond to the carbon atom in the above formula (1).

2. Before the resist pattern forming step, a step of heating the resist underlayer film at 200° C. or higher The method for manufacturing a semiconductor substrate according to claim 1 , further comprising:

3. 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 claim 1 or 2, further comprising:

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