Lithography film-forming material, composition, underlayer film for lithography, and pattern formation method

Abstract

The purpose of the present disclosure is to provide a film-forming material or the like that is for lithography, that is applicable in a wet process due to having high film-forming properties and solvent solubility, that has good curability, that can impart, to a film, excellent heat resistance, etching resistance, ability to be embedded in a multilevel substrate, and flatness, and that is useful for formation of a photoresist underlayer film. The film-forming material for lithography according to the present disclosure contains a compound having an amino group bonded to an aromatic ring. The compound is represented by, for example, formula (1A), formula (1B), formula (2), formula (3) or formula (4) in the description.

Description

[Technical Field]

[0001] The present invention relates to a film-forming material for lithography, a film-forming composition for lithography containing the material, an underlayer film for lithography formed using the composition, and a pattern-forming method (e.g., a method for forming a resist pattern or a method for forming a circuit pattern) using the composition. [Background technology]

[0002] In the manufacture of semiconductor devices, microfabrication is performed by lithography using photoresist materials. In recent years, with the increasing integration and speed of LSIs, further miniaturization by pattern rules is required. However, lithography, which uses optical exposure as a general-purpose technology, is approaching the intrinsic resolution limit due to the wavelength of the light source.

[0003] The wavelength of the lithography light source used in resist pattern formation has been shortened from KrF excimer lasers (248 nm) to ArF excimer lasers (193 nm). However, as resist patterns become finer, problems such as resolution and collapse of the resist pattern after development arise, making it desirable to thin the resist. However, simply thinning the resist makes it difficult to obtain a resist pattern with a thickness sufficient for substrate processing. Therefore, a process has become necessary in which a resist underlayer film is formed between the resist and the semiconductor substrate to be processed, and this resist underlayer film also functions as a mask during substrate processing.

[0004] Currently, various resist underlayer films for such processes are known. For example, a multilayer resist process underlayer film-forming material containing a resin component having at least a substituent that generates a sulfonic acid residue by elimination of an end group upon application of a predetermined energy, and a solvent, has been proposed to realize a resist underlayer film for lithography with a dry etching rate selectivity similar to that of a resist, unlike conventional resist underlayer films with a high etching rate (see Patent Document 1). Furthermore, a resist underlayer film material containing a polymer having a specific repeating unit has been proposed to realize a resist underlayer film for lithography with a dry etching rate selectivity lower than that of a resist (see Patent Document 2). Furthermore, a resist underlayer film material containing a polymer obtained by copolymerizing a repeating unit of an acenaphthylene derivative with a repeating unit having a substituted or unsubstituted hydroxy group has been proposed to realize a resist underlayer film for lithography with a dry etching rate selectivity lower than that of a semiconductor substrate (see Patent Document 3).

[0005] On the other hand, amorphous carbon underlayer films formed by CVD using methane gas, ethane gas, acetylene gas, or the like as raw materials are well known as materials having high etching resistance for this type of resist underlayer film.

[0006] The present inventors have also proposed an underlayer film-forming composition for lithography that contains a naphthalene formaldehyde polymer containing specific structural units and an organic solvent, as a material that has excellent optical properties and etching resistance, is soluble in solvents, and is applicable to wet processes (see Patent Documents 4 and 5).

[0007] Known methods for forming an intermediate layer used in forming a resist underlayer film in a three-layer process include a method for forming a silicon nitride film (see Patent Document 6) and a CVD method for forming a silicon nitride film (see Patent Document 7). Also, known intermediate layer materials for a three-layer process include materials containing silsesquioxane-based silicon compounds (see Patent Documents 8 and 9). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-177668 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-271838 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-250434 [Patent Document 4] International Publication No. 2009 / 072465 [Patent Document 5] International Publication No. 2011 / 034062 [Patent Document 6] Japanese Patent Application Laid-Open No. 2002-334869 [Patent Document 7] International Publication No. 2004 / 066377 [Patent Document 8] Japanese Patent Application Laid-Open No. 2007-226170 [Patent Document 9] Japanese Patent Application Laid-Open No. 2007-226204 Summary of the Invention

[0009] As described above, numerous film-forming materials for lithography have been proposed up to now, but none of them not only have high film-forming properties and solvent solubility that make them applicable to wet processes such as spin coating and screen printing, but also have a high level of curability, film heat resistance, film etching resistance, embeddability into uneven substrates, and film flatness, and therefore the development of new materials is required.

[0010] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a film-forming material for lithography that has high film-forming properties and solvent solubility, is applicable to wet processes, and is excellent in curability, film heat resistance, film etching resistance, embeddability into uneven substrates, and film flatness, and is useful for forming a photoresist underlayer film; a film-forming composition for lithography containing the material; an underlayer film for lithography formed using the composition; and a pattern formation method using the composition.

[0011] As a result of extensive research into solving the above problems, the present inventors have found that the above problems can be solved by using a compound having a specific structure, and have thus completed the present invention.

[0012] [1] A film-forming material for lithography containing a compound having an amino group bonded to an aromatic ring.

[0013] [2] The film-forming material for lithography according to the above [1], wherein the compound having an amino group bonded to an aromatic ring is a compound represented by the following formula (1A) and / or formula (1B):

[0014] [ka] (In formula (1A), X's each independently represent a single bond, -O-, -CH2-, -C(CH3)2-, -CO-, -C(CF3)2-, -CONH-, or -COO-; A is a single bond, an oxygen atom, or a divalent hydrocarbon group having 1 to 80 carbon atoms which may contain a heteroatom (that is, although it is clear from the structural formula, A is neither a monovalent group nor a trivalent or higher valent group), and among these, those other than a single bond are preferred, and those which do not contain a cycloalkane structure are further preferred; R 1 each independently represents a group having 0 to 30 carbon atoms which may contain a heteroatom, m 1 are each independently an integer of 0 to 4.

[0015] [ka] (In formula (1B), R 1 Each of R ' is independently a group having 0 to 30 carbon atoms which may contain a heteroatom, 1 at least one of ' is a hydroxymethyl group, a halooxymethyl group, or a methoxymethyl group; m 1 ' is an integer between 1 and 5.)

[0016] [3] The film-forming material for lithography according to the above [1], wherein the compound having an amino group bonded to an aromatic ring is a polymer of the formula (1A) and / or the formula (1B).

[0017] [4] A is a single bond, an oxygen atom, or any of the following structures, and among these, those other than a single bond are preferred, and further, those not containing a cycloalkane structure are preferred:

[0018] [ka] Y is a single bond, -O-, -CH2-, -C(CH3)2-, -C(CF3)2-,

[0019] [ka] That is, The film-forming material for lithography according to [2] or [3] above.

[0020] [5] X's are each independently a single bond, -O-, -C(CH3)2-, -CO-, or -COO-; A is a single bond, an oxygen atom, or the following structure, and among these, those other than a single bond are preferred, and further, those not containing a cycloalkane structure are preferred:

[0021] [ka] Y is —C(CH3)2— or —C(CF3)2—; The film-forming material for lithography according to [2] or [3] above.

[0022] [6] The film-forming material for lithography according to the above [1], wherein the compound having an amino group bonded to an aromatic ring is at least one selected from compounds represented by the following formulas (2), (3), and (4):

[0023] [ka] (In formula (2), R 2 are each independently a group having 0 to 10 carbon atoms which may contain a heteroatom, m 2 are each independently an integer of 0 to 3, m 2’ are each independently an integer of 0 to 4, n is an integer from 1 to 4.

[0024] [ka] (In formula (3), R 3 and R 4 are each independently a group having 0 to 10 carbon atoms which may contain a heteroatom, m 3 are each independently an integer of 0 to 4, m 4 are each independently an integer of 0 to 4, n is an integer from 0 to 4.

[0025] [ka] (In formula (4), R 5 are each independently a group having 0 to 10 carbon atoms which may contain a heteroatom, and m 5 are each independently an integer of 1 to 4, n is an integer from 2 to 10.

[0026] [7] The film-forming material for lithography according to any one of the above [2] to [5], wherein the heteroatom is selected from the group consisting of oxygen, fluorine, and silicon.

[0027] [8] The film-forming material for lithography according to any one of the above [1] to [7], further comprising a crosslinking agent.

[0028] [9] The film-forming material for lithography according to any one of the above [1] to [8], further comprising a crosslinking accelerator.

[0029]

[10] The film-forming material for lithography according to any one of the above [1] to [9], further comprising a radical polymerization initiator.

[0030]

[11] A film-forming composition for lithography, comprising the film-forming material for lithography according to any one of the above [1] to

[10] and a solvent.

[0031]

[12] The film-forming composition for lithography according to the above

[11] , further comprising an acid generator.

[0032]

[13] The film-forming composition for lithography according to the above

[11] or

[12] , further comprising a base generator.

[0033]

[14] The composition for forming a film for lithography according to any one of the above

[11] to

[13] , wherein the film for lithography is an underlayer film for lithography.

[0034]

[15] An underlayer film for lithography formed using the film-forming composition for lithography according to

[14] above.

[0035]

[16] forming an underlayer film on a substrate using the film-forming composition for lithography described in

[14] above; forming at least one photoresist layer on the underlayer film; irradiating predetermined areas of the photoresist layer with radiation and developing; A pattern forming method comprising:

[0036]

[17] forming an underlayer film on a substrate using the film-forming composition for lithography described in

[14] above; forming an intermediate layer film on the underlayer film using a resist intermediate layer film material containing silicon atoms; forming at least one photoresist layer on the intermediate layer film; irradiating predetermined areas of the photoresist layer with radiation and developing to form a resist pattern; a step of etching the intermediate layer film using the resist pattern as a mask to obtain an intermediate layer film pattern; a step of etching the underlayer film using the intermediate layer film pattern as an etching mask to obtain an underlayer film pattern; and a step of etching the substrate using the underlayer film pattern as an etching mask to form a pattern on the substrate; A pattern forming method comprising:

[0037] According to the present invention, it is possible to provide a film-forming material for lithography that has high film-forming properties and solvent solubility, making it applicable to wet processes, and that is excellent in curability, film heat resistance, film etching resistance, embeddability into uneven substrates, and film flatness, and is useful for forming a photoresist underlayer film; a film-forming composition for lithography containing the material; an underlayer film for lithography formed using the composition; and a pattern formation method using the composition. DETAILED DESCRIPTION OF THE INVENTION

[0038] The following describes embodiments of the present invention. Note that the following embodiments are merely examples for explaining the present invention, and the present invention is not limited to these embodiments, and various modifications are possible without departing from the spirit of the present invention.

[0039] This embodiment is an example of a film-forming material for lithography containing a compound having an amino group bonded to an aromatic ring (hereinafter referred to as an "aniline-based compound"). From the viewpoint of sublimation resistance during high-temperature baking, the content of the aniline-based compound in the film-forming material for lithography of this embodiment is preferably 51 to 100 mass%, more preferably 60 to 100 mass%, even more preferably 70 to 100 mass%, and particularly preferably 80 to 100 mass%.

[0040] The aniline-based compound in the film-forming material for lithography of this embodiment is characterized by having a function other than that of a basic compound.

[0041] The aniline-based material of this embodiment is preferably a compound represented by the following formula (1A) and / or formula (1B).

[0042] [ka]

[0043] In formula (1A), X's are each independently a single bond, -O-, -CH2-, -C(CH3)2-, -CO-, -C(CF3)2-, -CONH-, or -COO-. A's are single bonds, oxygen atoms, or divalent hydrocarbon groups having 6 to 80 carbon atoms which may contain heteroatoms. R 1 are each independently a group having 0 to 30 carbon atoms which may contain a heteroatom, and m 1 are each independently an integer of 0 to 4.

[0044] [ka]

[0045] In formula (1B), R 1 Each of R ' is independently a group having 0 to 30 carbon atoms which may contain a heteroatom, 1 At least one of m is a hydroxymethyl group, a halooxymethyl group, or a methoxymethyl group. 1 ' is an integer between 1 and 5.

[0046] More preferably, from the viewpoint of improving heat resistance, A in formula (1A) is a single bond, an oxygen atom, or a divalent hydrocarbon group containing an aromatic ring having 6 to 80 carbon atoms and optionally containing a heteroatom, even more preferably a single bond, an oxygen atom, or any of the following structures, and even more preferably, among these, anything other than a single bond and further, one that does not contain a cycloalkane structure.

[0047] [ka]

[0048] where Y is a single bond, -O-, -CH2-, -C(CH3)2-, -C(CF3)2-,

[0049] [ka] is.

[0050] More preferably, in formula (1A), X is each independently a single bond, -O-, -C(CH3)2-, -CO-, or -COO-, and A is a single bond, an oxygen atom, or the following structure, and even more preferably, among these, it is other than a single bond and does not contain a cycloalkane structure.

[0051] [ka]

[0052] Here, Y is —C(CH3)2— or —C(CF3)2—.

[0053] X is more preferably a single bond from the viewpoint of heat resistance, more preferably -COO- from the viewpoint of solubility, and more preferably -O- or -C(CH3)2- from the viewpoint of film flatness. Furthermore, Y is more preferably a single bond from the viewpoint of improving heat resistance. Furthermore, R 1 is more preferably a group having 0 to 20 or 0 to 10 carbon atoms which may contain a heteroatom (for example, oxygen, nitrogen, sulfur, fluorine, chlorine, bromine, or iodine). 1 is preferably a hydrocarbon group from the viewpoint of improving solubility in organic solvents. 1 Examples of the alkyl group include alkyl groups (for example, alkyl groups having 1 to 6 or 1 to 3 carbon atoms), and specific examples thereof include methyl groups and ethyl groups. 1 It is more preferable that ' is an integer of 0 to 2, and even more preferable that it is 1 or 2 from the viewpoint of raw material availability and improved solubility.

[0054] From the viewpoint of improving heat resistance, the aniline compound of the present embodiment is preferably any one of the compounds represented by the following formula (2), formula (3), and formula (4).

[0055] [ka]

[0056] In formula (2), R 2 are each independently a group having 0 to 10 carbon atoms which may contain a heteroatom (for example, oxygen, nitrogen, sulfur, fluorine, chlorine, bromine, or iodine), and are preferably a hydrocarbon group from the viewpoint of improving solubility in organic solvents. For example, R 2 Examples of the alkyl group include alkyl groups (for example, alkyl groups having 1 to 6 or 1 to 3 carbon atoms), and specific examples thereof include methyl groups and ethyl groups. 2 are each independently an integer of 0 to 3, preferably 0 or 1, and more preferably 0 from the viewpoint of raw material availability. 2’ are each independently an integer of 0 to 4, preferably 0 or 1, and from the viewpoint of raw material availability, more preferably 0. Furthermore, n is an integer of 0 to 4, preferably an integer of 1 to 4 or 0 to 2, and from the viewpoint of improving reactivity, more preferably an integer of 1 or 2.

[0057] [ka]

[0058] In formula (3), R 3 and R 4 are each independently a group having 0 to 10 carbon atoms which may contain a heteroatom (for example, oxygen, nitrogen, sulfur, fluorine, chlorine, bromine, or iodine), and are preferably a hydrocarbon group from the viewpoint of improving solubility in organic solvents. For example, R 3 and R 4 Examples of the alkyl group include alkyl groups (for example, alkyl groups having 1 to 6 or 1 to 3 carbon atoms), and specific examples thereof include methyl groups and ethyl groups. 3 are each independently an integer of 0 to 4, preferably an integer of 0 to 2, and more preferably 0 from the viewpoint of availability of raw materials. 4are each independently an integer of 0 to 4, preferably an integer of 0 to 2, and from the viewpoint of availability of raw materials, more preferably 0. Furthermore, n is an integer of 0 to 4, preferably an integer of 1 to 4 or 0 to 2, and from the viewpoint of reactivity, more preferably an integer of 1 or 2.

[0059] [ka]

[0060] In formula (4), R 5 are each independently a group having 0 to 10 carbon atoms which may contain a heteroatom. 5 is preferably a hydrocarbon group from the viewpoint of improving solubility in organic solvents. 5 Examples of the alkyl group include alkyl groups (for example, alkyl groups having 1 to 6 or 1 to 3 carbon atoms), and specific examples thereof include methyl groups and ethyl groups. 5 are each independently an integer of 1 to 4, preferably an integer of 1 or 2, and from the viewpoint of raw material availability, more preferably 1. Furthermore, n is an integer of 2 to 10, preferably an integer of 3 to 10 from the viewpoint of sublimation property, and more preferably an integer of 3 to 8 from the viewpoint of reactivity.

[0061] Moreover, from the viewpoint of further improving heat resistance, the aniline compound of the present embodiment is preferably a polymer of formula (1A) and / or formula (1B).

[0062] The lithography film-forming material of this embodiment can be applied to wet processes. Furthermore, the lithography film-forming material of this embodiment has an aromatic skeleton and is excellent in heat resistance and etching resistance. Furthermore, a rigid structure is easily formed by baking, film deterioration during high-temperature baking is suppressed, and an underlayer film with excellent heat resistance and etching resistance can be formed. Furthermore, despite having an aromatic structure, the lithography film-forming material of this embodiment has high solubility in organic solvents and high solubility in safe solvents. Furthermore, a lithography underlayer film made from the lithography film-forming composition of this embodiment, which will be described later, not only has excellent embedding properties in uneven substrates and film flatness, and good product quality stability, but also has excellent adhesion to resist layers and resist intermediate layer film materials, allowing for the formation of excellent resist patterns.

[0063] Specific examples of the aniline-based compounds used in this embodiment include 2,2-bis(4-aminophenyl)propane, 1,1-bis(4-aminophenyl)-1-phenylethane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)butane, bis(4-aminophenyl)diphenylmethane, 2,2-bis(3-methyl-4-aminophenyl)propane, bis(4-aminophenyl)-2,2-dichloroethylene, 1,1-bis(4-aminophenyl)ethane, bis(4-aminophenyl)methane, and 2,2-bis(4-amino-3-isopropylphenyl) Examples of the alkyl ether include propane, 1,3-bis(2-(4-aminophenyl)-2-propyl)benzene, bis(4-aminophenyl)sulfone, 5,5'-(1-methylethylidene)-bis[1,1'-(bisphenyl)-2-amino]propane, 1,1-bis(4-aminophenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-aminophenyl)cyclohexane, 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene, 3,3'-(1,3-phenylenebis)oxydianiline, and 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane.

[0064] Specific examples of the compounds represented by the above formulas (2), (3), and (4) include, but are not limited to, compounds represented by the following formulas:

[0065] [ka]

[0066] <Crosslinking agent> The film-forming material for lithography of this embodiment may contain, in addition to the aniline-based compound, a crosslinking agent as needed from the viewpoint of lowering the curing temperature and suppressing intermixing.

[0067] The crosslinking agent is not particularly limited as long as it crosslinks with the aniline compound, and any known crosslinking system can be used. Specific examples of crosslinking agents that can be used in this embodiment include, but are not limited to, phenol compounds, epoxy compounds, maleimide compounds, cyanate compounds, benzoxazine compounds, acrylate compounds, melamine compounds, guanamine compounds, glycoluril compounds, urea compounds, isocyanate compounds, and azide compounds. These crosslinking agents can be used alone or in combination of two or more. Among these, benzoxazine compounds and epoxy compounds are preferred, and epoxy compounds are more preferred from the viewpoint of reactivity.

[0068] In the crosslinking reaction between an aniline compound and a crosslinking agent, for example, the active groups of these crosslinking agents (phenolic hydroxyl groups, epoxy groups, maleimide groups, cyanate groups, or phenolic hydroxyl groups formed by ring-opening of the alicyclic moiety of benzoxazine) react with amino groups to form crosslinks, and also add to aromatic rings in the aniline compound to form crosslinks.

[0069] The epoxy compound can be a known compound selected from those having two or more epoxy groups in one molecule. Examples include those described in International Publication No. 2018 / 016614. The epoxy compound may be used alone or in combination of two or more types. From the viewpoints of heat resistance and solubility, epoxy resins that are solid at room temperature, such as epoxy resins obtained from phenol aralkyl resins and biphenyl aralkyl resins, are preferred.

[0070] In this embodiment, a crosslinking agent having at least one allyl group may be used from the viewpoint of improving crosslinkability. Examples of crosslinking agents having at least one allyl group include those described in International Publication No. 2018 / 016614. The crosslinking agent having at least one allyl group may be used alone or in a mixture of two or more types.

[0071] The lithography film-forming material of this embodiment can be formed by crosslinking and curing the aniline compound alone or in combination with a crosslinking agent using a known method. Examples of crosslinking methods include thermal curing and photocuring.

[0072] The content of the crosslinking agent is usually in the range of 0.1 to 10,000 parts by mass, and from the viewpoint of heat resistance and solubility, is preferably in the range of 0.1 to 1,000 parts by mass, more preferably in the range of 0.1 to 100 parts by mass, even more preferably in the range of 1 to 50 parts by mass, and particularly preferably in the range of 1 to 30 parts by mass, relative to 100 parts by mass of the aniline compound.

[0073] A crosslinking accelerator for accelerating crosslinking and curing reactions can be used in the lithography film-forming material of this embodiment, if necessary. The crosslinking accelerator is not particularly limited as long as it accelerates the crosslinking and curing reactions, and examples thereof include amines, imidazoles, organic phosphines, Lewis acids, and the like. These crosslinking accelerators can be used alone or in combination of two or more. Among these, imidazoles or organic phosphines are preferred, and imidazoles are more preferred from the viewpoint of lowering the crosslinking temperature. Examples of the crosslinking accelerator include those described in International Publication No. 2018 / 016614.

[0074] The amount of the crosslinking accelerator to be added is usually preferably in the range of 0.1 to 10 parts by mass, more preferably in the range of 0.1 to 5 parts by mass, and even more preferably in the range of 0.1 to 3 parts by mass, from the viewpoint of ease of control and economic efficiency, when the mass of the aniline compound is taken as 100 parts by mass.

[0075] The film-forming material for lithography of this embodiment may contain a latent base generator for promoting crosslinking and curing reactions, if necessary. Known base generators include those that generate a base by thermal decomposition and those that generate a base by light irradiation, and any of these may be used.

[0076] <Radical polymerization initiator> The lithography film-forming material of this embodiment can be blended with a radical polymerization initiator to promote crosslinking and curing reactions as needed. The radical polymerization initiator may be a photopolymerization initiator that initiates radical polymerization using light, or a thermal polymerization initiator that initiates radical polymerization using heat. Examples of such radical polymerization initiators include those described in International Publication No. 2018 / 016614. The radical polymerization initiator of this embodiment may be used alone or in combination of two or more.

[0077] [Method for purifying a film-forming material for lithography] The lithography film-forming material can be purified by washing with ion-exchanged water. The purification method includes dissolving the lithography film-forming material in a water-immiscible organic solvent to obtain an organic phase, contacting the organic phase with ion-exchanged water to perform an extraction process, thereby transferring metals contained in the organic phase containing the lithography film-forming material and the organic solvent to the aqueous phase, and then separating the organic and aqueous phases. This purification can reduce the content of various metals in the lithography film-forming material of the present invention.

[0078] The water-immiscible organic solvent is not particularly limited, but is preferably an organic solvent that can be safely used in semiconductor manufacturing processes. The amount of the organic solvent used is usually about 1 to 100 times by mass relative to the film-forming material for lithography used.

[0079] Specific examples of the organic solvent to be used include those described in International Publication No. 2015 / 080240. Among these, toluene, 2-heptanone, cyclohexanone, cyclopentanone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, ethyl acetate, etc. are preferred, with cyclohexanone and propylene glycol monomethyl ether acetate being particularly preferred. These organic solvents can be used alone or in combination of two or more.

[0080] The temperature during the extraction treatment is usually 20 to 90°C, preferably in the range of 30 to 80°C. The extraction operation is carried out, for example, by thoroughly mixing the mixture by stirring or the like, followed by allowing it to stand. This allows the metal components contained in the solution containing the lithographic film-forming material and organic solvent to migrate into the aqueous phase. This operation also reduces the acidity of the solution, making it possible to suppress deterioration of the lithographic film-forming material used.

[0081] After the extraction treatment, the solution phase containing the lithography film-forming material and the organic solvent to be used is separated from the aqueous phase, and the solution containing the organic solvent is recovered by decantation or the like. The time for standing is not particularly limited, but a too short time for standing is undesirable because it results in poor separation of the solution phase containing the organic solvent from the aqueous phase. The time for standing is usually 1 minute or more, more preferably 10 minutes or more, and even more preferably 30 minutes or more. The extraction treatment may be performed only once, but it is also effective to repeat the steps of mixing, standing, and separation multiple times.

[0082] Water mixed in the solution containing the lithographic film-forming material and the organic solvent thus obtained can be easily removed by vacuum distillation, etc. Furthermore, the concentration of the lithographic film-forming material can be adjusted to any desired concentration by adding an organic solvent, if necessary.

[0083] The method for obtaining only the film-forming material for lithography from the obtained solution containing the organic solvent can be performed by a known method such as removal under reduced pressure, separation by reprecipitation, a combination thereof, etc. Furthermore, known treatments such as concentration, filtration, centrifugation, drying, etc. can be performed as necessary.

[0084] [Film-forming composition for lithography] The composition for forming a film for lithography according to the present embodiment contains the film-forming material for lithography and a solvent. The film for lithography is, for example, an underlayer film for lithography.

[0085] The film-forming composition for lithography of the present embodiment can be applied to a substrate, and then heated, if necessary, to evaporate the solvent, followed by heating or light irradiation to form a desired cured film. The film-forming composition for lithography of the present embodiment can be applied by any method, and for example, methods such as spin coating, dipping, flow coating, inkjet coating, spraying, bar coating, gravure coating, slit coating, roll coating, transfer printing, brush coating, blade coating, and air knife coating can be appropriately used.

[0086] The heating temperature of the film is not particularly limited for the purpose of evaporating the solvent, and can be, for example, 40 to 400°C. The heating method is also not particularly limited, and for example, evaporation can be performed using a hot plate or oven in an appropriate atmosphere, such as air, an inert gas such as nitrogen, or a vacuum. The heating temperature and heating time can be selected according to the processing steps of the target electronic device, and heating conditions can be selected such that the physical properties of the resulting film conform to the required characteristics of the electronic device. The conditions for light irradiation are also not particularly limited, and appropriate irradiation energy and irradiation time can be adopted depending on the lithography film-forming material used.

[0087] <Solvent> The solvent used in the lithography film-forming composition of this embodiment is not particularly limited as long as it can dissolve at least the aniline-based compound of this embodiment, and known solvents can be used as appropriate. Specific examples of solvents include those described in International Publication No. 2013 / 024779. These solvents can be used alone or in combination of two or more. Among these solvents, cyclohexanone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, methyl hydroxyisobutyrate, and anisole are particularly preferred from the standpoint of safety.

[0088] The content of the solvent is not particularly limited, but from the viewpoint of solubility and film formation, it is preferably 25 to 9900 parts by mass, more preferably 400 to 7900 parts by mass, and even more preferably 900 to 4900 parts by mass, relative to 100 parts by mass of the aniline-based compound in the lithography film-forming material.

[0089] <Acid generator> The film-forming composition for lithography of the present embodiment may contain an acid generator as needed from the viewpoint of further promoting the crosslinking reaction, etc. Known acid generators include those that generate acid by thermal decomposition and those that generate acid by light irradiation, and either of these can be used.

[0090] Examples of acid generators include those described in International Publication No. 2013 / 024779 by the present applicant, and the disclosure of acid generators in this patent document is incorporated herein by reference.

[0091] In the film-forming composition for lithography of this embodiment, the content of the acid generator is not particularly limited, but is preferably 0 to 50 parts by mass, and more preferably 0 to 40 parts by mass, relative to 100 parts by mass of the aniline-based compound in the film-forming material for lithography. By setting the content within the above preferred range, the crosslinking reaction tends to be enhanced, and the occurrence of mixing with the resist layer tends to be suppressed.

[0092] <Basic compounds> Furthermore, the composition for forming an underlayer film for lithography according to this embodiment may contain a basic compound from the viewpoint of improving storage stability, etc. The basic compound functions as an acid quencher to prevent a small amount of acid generated from the acid generator from proceeding with a crosslinking reaction. Examples of such basic compounds include, but are not limited to, primary, secondary, or tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amide derivatives, and imide derivatives, as described in International Publication No. 2013 / 024779.

[0093] In the film-forming composition for lithography of this embodiment, the content of the basic compound is not particularly limited, but is preferably 0 to 2 parts by mass, more preferably 0 to 1 part by mass, based on 100 parts by mass of the aniline-based compound in the film-forming material for lithography. By setting the content within the above preferred range, storage stability tends to be improved without excessively impairing the crosslinking reaction.

[0094] Furthermore, the film-forming composition for lithography of the present embodiment may contain known additives, including, but not limited to, ultraviolet absorbers, antifoaming agents, colorants, pigments, nonionic surfactants, anionic surfactants, and cationic surfactants.

[0095] [Underlayer film for lithography and pattern formation method] The underlayer film for lithography of this embodiment is formed using the film-forming composition for lithography of this embodiment.

[0096] The pattern formation method of this embodiment also includes a step (A-1) of forming an underlayer film on a substrate using the film-forming composition for lithography of this embodiment, a step (A-2) of forming at least one photoresist layer on the underlayer film, and, after step (A-2), a step (A-3) of irradiating a predetermined region of the photoresist layer with radiation and performing development.

[0097] Furthermore, another pattern formation method of this embodiment includes the steps of: (B-1) forming an underlayer film on a substrate using the lithography film-forming composition of this embodiment; (B-2) forming an intermediate layer film on the underlayer film using a resist intermediate layer film material containing silicon atoms; (B-3) forming at least one photoresist layer on the intermediate layer film; (B-4) irradiating a predetermined region of the photoresist layer with radiation and developing it to form a resist pattern; and (B-5) etching the intermediate layer film using the resist pattern as a mask after step (B-4), etching the underlayer film using the obtained intermediate layer film pattern as an etching mask, and etching the substrate using the obtained underlayer film pattern as an etching mask to form a pattern on the substrate.

[0098] The method for forming the underlayer film for lithography of the present embodiment is not particularly limited as long as it is formed from the film-forming composition for lithography of the present embodiment, and known methods can be applied. For example, the underlayer film can be formed by applying the film-forming composition for lithography of the present embodiment to a substrate by a known coating method or printing method such as spin coating or screen printing, and then removing the organic solvent by volatilization or the like.

[0099] When forming the underlayer film, baking is preferably performed to prevent mixing with the upper layer resist and promote the crosslinking reaction. In this case, the baking temperature is not particularly limited, but is preferably in the range of 80 to 450°C, and more preferably 200 to 400°C. The baking time is also not particularly limited, but is preferably in the range of 10 to 300 seconds. The thickness of the underlayer film can be appropriately selected depending on the required performance, and is not particularly limited, but is usually preferably 30 to 20,000 nm, more preferably 50 to 15,000 nm, and even more preferably 50 to 1,000 nm.

[0100] After forming an underlayer film on a substrate, it is preferable to form a silicon-containing resist layer or a monolayer resist made of a normal hydrocarbon on the underlayer film in the case of a two-layer process, or a silicon-containing intermediate layer and a silicon-free monolayer resist on the silicon-containing intermediate layer in the case of a three-layer process. In this case, known photoresist materials can be used to form these resist layers.

[0101] From the viewpoint of oxygen gas etching resistance, silicon-containing resist materials for two-layer processes are preferably positive photoresist materials that use a silicon atom-containing polymer such as a polysilsesquioxane derivative or a vinylsilane derivative as a base polymer, and further contain an organic solvent, an acid generator, and optionally a basic compound, etc. Here, the silicon atom-containing polymer can be any known polymer used in this type of resist material.

[0102] A polysilsesquioxane-based intermediate layer is preferably used as the silicon-containing intermediate layer for the three-layer process. By providing the intermediate layer with an anti-reflection coating effect, reflection tends to be effectively suppressed. For example, in a 193 nm exposure process, if a material containing many aromatic groups and having high substrate etching resistance is used as the underlayer film, the k value tends to be high and the substrate reflection tends to be high. However, by suppressing reflection with an intermediate layer, the substrate reflection can be reduced to 0.5% or less. While there are no particular limitations on the intermediate layer with such anti-reflection effect, for 193 nm exposure, a polysilsesquioxane that is crosslinked by acid or heat and that has a light-absorbing group having a phenyl group or a silicon-silicon bond introduced therein is preferably used.

[0103] Alternatively, an intermediate layer formed by CVD (Chemical Vapor Deposition) can be used. While there is no particular limitation on intermediate layers produced by CVD that are highly effective as anti-reflection films, SiON films are known, for example. Generally, forming an intermediate layer by a wet process such as spin coating or screen printing is simpler and more cost-effective than using CVD. The top layer resist in a three-layer process may be either positive or negative, and the same resist as a commonly used single-layer resist can be used.

[0104] Furthermore, the underlayer film of this embodiment can be used as an anti-reflection film for a normal single-layer resist or as an underlayer material for suppressing pattern collapse. Because the underlayer film of this embodiment has excellent etching resistance for underlayer processing, it can also be expected to function as a hard mask for underlayer processing.

[0105] When forming a resist layer using a photoresist material, wet processes such as spin coating and screen printing are preferably used, as in the case of forming an underlayer film. After applying the resist material by spin coating or the like, pre-baking is typically performed, preferably at 80 to 180°C for 10 to 300 seconds. Thereafter, exposure, post-exposure baking (PEB), and development are performed according to conventional methods to obtain a resist pattern. The thickness of the resist film is not particularly limited, but is generally preferably 30 to 500 nm, more preferably 50 to 400 nm.

[0106] The exposure light may be appropriately selected depending on the photoresist material used, and generally includes high-energy rays with a wavelength of 300 nm or less, specifically excimer lasers with wavelengths of 248 nm, 193 nm, and 157 nm, soft X-rays with wavelengths of 3 to 20 nm, electron beams, X-rays, etc.

[0107] The resist pattern formed by the above-described method is prevented from collapsing due to the underlayer film of this embodiment, and therefore, by using the underlayer film of this embodiment, a finer pattern can be obtained and the exposure dose required to obtain the resist pattern can be reduced.

[0108] Next, etching is performed using the resulting resist pattern as a mask. Gas etching is preferably used to etch the underlayer film in the two-layer process. For gas etching, oxygen gas is preferred. In addition to oxygen gas, inert gases such as He and Ar, or CO, CO2, NH3, SO2, N2, NO2, and H2 gases can also be added. Gas etching can also be performed using only CO, CO2, NH3, N2, NO2, and H2 gases without oxygen gas. The latter gases are particularly preferred for sidewall protection to prevent undercutting of the pattern sidewalls.

[0109] On the other hand, gas etching is also preferably used for etching the intermediate layer in the three-layer process. As the gas etching, the same as that described in the two-layer process can be applied. In particular, the processing of the intermediate layer in the three-layer process is preferably performed using a fluorocarbon-based gas and a resist pattern as a mask. Thereafter, as described above, the processing of the lower layer film can be performed by, for example, performing oxygen gas etching using the intermediate layer pattern as a mask.

[0110] When an inorganic hard mask intermediate layer film is formed as the intermediate layer, a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiON film) is formed by a CVD method, an ALD method, or the like. The method for forming the nitride film is not particularly limited, but for example, the methods described in JP 2002-334869 A (Patent Document 6) and WO 2004 / 066377 (Patent Document 7) can be used. A photoresist film can be formed directly on such an intermediate layer film, or an organic antireflective coating (BARC) can be formed on the intermediate layer film by spin coating, and then a photoresist film can be formed on top of that.

[0111] A polysilsesquioxane-based intermediate layer is also preferably used as the intermediate layer. By providing the resist intermediate layer with an anti-reflection coating effect, reflection tends to be effectively suppressed. Specific materials for the polysilsesquioxane-based intermediate layer are not particularly limited, but for example, those described in JP 2007-226170 A (Patent Document 8) and JP 2007-226204 A (Patent Document 9) can be used.

[0112] The subsequent etching of the substrate can also be performed by conventional methods. For example, if the substrate is SiO2 or SiN, etching can be performed primarily with fluorocarbon-based gases, and if it is p-Si, Al, or W, etching can be performed primarily with chlorine- or bromine-based gases. When etching the substrate with fluorocarbon-based gases, the silicon-containing resist of the two-layer resist process and the silicon-containing intermediate layer of the three-layer process are stripped simultaneously with substrate processing. On the other hand, when etching the substrate with chlorine- or bromine-based gases, the silicon-containing resist layer or silicon-containing intermediate layer is stripped separately, and generally, dry etching stripping using fluorocarbon-based gases is performed after substrate processing.

[0113] The underlayer film of this embodiment is characterized by its excellent etching resistance against these substrates. The substrate can be appropriately selected from known materials and is not particularly limited, but examples include Si, α-Si, p-Si, SiO2, SiN, SiON, W, TiN, and Al. The substrate may also be a laminate having a film to be processed (substrate to be processed) on a base material (support). Examples of such a film to be processed include various low-k films such as Si, SiO2, SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, and Al-Si, as well as stopper films therefor. Typically, a film made of a different material from the base material (support) is used. The thickness of the substrate or film to be processed is not particularly limited, but is typically about 50 to 1,000,000 nm, and more preferably 75 to 500,000 nm. [Example]

[0114] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples in any way.

[0115] <Production Example 1> A 10 L four-neck flask with a bottomless opening was prepared, equipped with a Dimroth condenser, a thermometer, and a stirring blade. Under a nitrogen stream, 1.09 kg (7 mol) of 1,5-dimethylnaphthalene (manufactured by Mitsubishi Gas Chemical Company, Inc.), 2.1 kg of 40% by weight formalin aqueous solution (28 mol as formaldehyde, manufactured by Mitsubishi Gas Chemical Company, Inc.), and 0.97 ml of 98% by weight sulfuric acid (manufactured by Kanto Chemical Co., Inc.) were charged into the four-neck flask and refluxed at 100°C under atmospheric pressure for 7 hours. Subsequently, 1.8 kg of ethylbenzene (manufactured by Wako Pure Chemical Industries, Ltd., special grade reagent) was added as a dilution solvent to the reaction solution. After allowing to stand, the lower aqueous phase was removed. The mixture was neutralized and washed with water. The ethylbenzene and unreacted 1,5-dimethylnaphthalene were distilled off under reduced pressure to obtain 1.25 kg of a light brown solid dimethylnaphthalene formaldehyde resin. The molecular weight of the obtained dimethylnaphthalene formaldehyde resin was a number average molecular weight (Mn): 562, a weight average molecular weight (Mw): 1168, and a dispersity (Mw / Mn): 2.08.

[0116] Next, a 0.5 L four-neck flask equipped with a Dimroth condenser, thermometer, and stirring blade was prepared. Under a nitrogen stream, 100 g (0.51 mol) of the dimethylnaphthalene formaldehyde resin obtained as described above and 0.05 g of paratoluenesulfonic acid were charged into the four-neck flask. The temperature was raised to 190°C and heated for 2 hours, followed by stirring. 52.0 g (0.36 mol) of 1-naphthol was then added, and the temperature was raised to 220°C and reacted for 2 hours. After dilution with a solvent, the mixture was neutralized and washed with water. The solvent was removed under reduced pressure to obtain 126.1 g of a black-brown solid modified resin (CR-1). The resulting resin (CR-1) had an Mn of 885, an Mw of 2220, and an Mw / Mn ratio of 2.51.

[0117] Thermogravimetry (TG) showed that the thermal weight loss of the resulting resin at 400°C was over 25% (evaluation C). Therefore, it was evaluated as being difficult to apply to high-temperature baking. Furthermore, evaluation of the solubility in PGMEA showed that it was 10% by mass or more (evaluation A), indicating sufficient solubility. The above Mn, Mw, and Mw / Mn were measured by gel permeation chromatography (GPC) analysis under the following conditions to determine the molecular weight in terms of polystyrene. Apparatus: Shodex GPC-101 (Showa Denko K.K.) Column: KF-80M x 3 Eluent: THF 1mL / min Temperature: 40℃

[0118] Example 1 A film-forming composition for lithography was prepared by adding 95 parts by mass of PGMEA as a solvent to 5 parts by mass of 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene (product name: Bisaniline P, manufactured by Mitsui Fine Chemicals, Inc., BAP below), and stirring the mixture at room temperature with a stirrer for at least 3 hours.

[0119] [ka]

[0120] Example 2 A film-forming composition for lithography was prepared in the same manner as in Example 1, except that 3,3'-(1,3-phenylenebis)oxydianiline (product name: APB-N, manufactured by Mitsui Fine Chemicals, Inc., APB-N below) was used instead of 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene.

[0121] [ka]

[0122] Example 3 A film-forming composition for lithography was prepared in the same manner as in Example 1, except that 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (product name: HFBAPP, manufactured by Wakayama Seika Kogyo Co., Ltd., HFBAPP below) was used instead of 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene.

[0123] [ka]

[0124] Example 4 A film-forming composition for lithography was prepared in the same manner as in Example 1, except that a diaminodiphenylmethane oligomer (PAN shown below) obtained by reproducing Synthesis Example 6 of JP-A No. 2001-26571 was used instead of 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene.

[0125] [ka]

[0126] Example 5 A film-forming composition for lithography was prepared in the same manner as in Example 1, except that a biphenylaralkyl polyaniline resin (product name: BAN, manufactured by Nippon Kayaku Co., Ltd., hereinafter referred to as BAN) was used instead of 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene.

[0127] [ka]

[0128] Example 6 A film-forming composition for lithography was prepared by adding 95 parts by weight of PGMEA as a solvent to 5 parts by weight of 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene (the BAP described above), using 2 parts by weight of a biphenylaralkyl epoxy resin represented by the following formula (product name: NC-3000-L, manufactured by Nippon Kayaku Co., Ltd., NC-3000-L described below) as a crosslinking agent, and adding 0.1 parts by weight of 2,4,5-triphenylimidazole (TPIZ) as a crosslinking accelerator. The mixture was stirred at room temperature with a stirrer for at least 3 hours. In the formula, n is an integer from 1 to 4.

[0129] [ka]

[0130] Example 7 A film-forming composition for lithography was prepared in the same manner as in Example 6, except that 3,3'-(1,3-phenylenebis)oxydianiline (APB-N above) was used instead of 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene.

[0131] Example 8 A film-forming composition for lithography was prepared in the same manner as in Example 6, except that 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP) was used instead of 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene.

[0132] Example 9 A film-forming composition for lithography was prepared in the same manner as in Example 6, except that a diaminodiphenylmethane oligomer (PAN) obtained by reproducing Synthesis Example 6 of JP-A-2001-26571 was used instead of 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene.

[0133] Example 10 A film-forming composition for lithography was prepared in the same manner as in Example 6, except that a biphenylaralkyl polyaniline resin (the above-mentioned BAN) was used instead of 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene.

[0134] Example 11 A film-forming composition for lithography was prepared in the same manner as in Example 10, except that 1 part by mass of a biphenyl aralkyl epoxy resin (product name: NC-3000-L, manufactured by Nippon Kayaku Co., Ltd., the above-mentioned NC-3000-L) was used as the crosslinking agent.

[0135] Example 12 A film-forming composition for lithography was prepared in the same manner as in Example 6, except that benzoxazine (BF-BXZ) represented by the following formula was used as the crosslinking agent.

[0136] [ka]

[0137] Example 13 A film-forming composition for lithography was prepared in the same manner as in Example 11, except that a diaminodiphenylmethane oligomer (PAN) obtained by reproducing Synthesis Example 6 of JP-A-2001-26571 was used instead of 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene.

[0138] (Comparative Example 1) A film-forming composition for lithography was prepared in the same manner as in Example 1, except that CR-1 obtained in Production Example 1 was used instead of 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene.

[0139] (Comparative Example 2) A film-forming composition for lithography was prepared in the same manner as in Example 6, except that CR-1 obtained in Production Example 1 was used instead of 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene.

[0140] <Evaluation of properties of film-forming compositions for lithography in Examples 1 to 13 and Comparative Examples 1 and 2>

[0141] [Evaluation of Solvent Solubility] The film-forming compositions for lithography of Examples 1 to 13 and Comparative Examples 1 and 2 and propylene glycol monomethyl ether acetate (PGMEA) were charged into a 50 ml screw bottle and stirred with a magnetic stirrer at 23°C for 1 hour. The amount of each film-forming composition for lithography dissolved in PGMEA was then measured, and the solvent solubility was evaluated according to the following evaluation criteria. From a practical standpoint, the following rating of S, A, or B is preferable. A rating of S, A, or B indicates high storage stability in solution and is fully applicable to edge beat rinse solutions (PGME / PGMEA mixtures) widely used in semiconductor microfabrication processes.

[0142] <Evaluation criteria> S: 15% by mass or more and less than 35% by mass A: 5% by mass or more and less than 15% by mass B: Less than 5% by mass

[0143] [Evaluation of curability] The lithography film-forming compositions of Examples 1 to 13 and Comparative Examples 1 and 2, each having the composition shown in Table 1, were spin-coated onto a silicon substrate, then baked at 150°C for 60 seconds, and the thickness of the coated film was measured. The silicon substrate was then immersed in a mixed solvent of 70% PGMEA / 30% PGME for 60 seconds, and the adhering solvent was removed with an aero duster, followed by solvent drying at 110°C. The film thickness reduction rate (%) was calculated from the difference in film thickness before and after immersion, and the curability of each underlayer film was evaluated according to the evaluation criteria shown below.

[0144] <Evaluation criteria> S: Film thickness reduction rate before and after solvent immersion ≦1% A: 1%< film thickness reduction rate before and after solvent immersion≦5% B: Film thickness reduction rate before and after solvent immersion > 5%

[0145] [Evaluation of film formation] The lithography film-forming compositions of Examples 1 to 13 and Comparative Examples 1 and 2 having the compositions shown in Table 1 were spin-coated onto a silicon substrate, and then baked at 150°C for 60 seconds, and the condition of the film and defects of 0.5 μm or larger on the film were visually evaluated.

[0146] <Evaluation criteria> S: 1cm 2 Fewer than 5 defects per hit A: 1cm 2 5 or more defects B: Unable to form a film.

[0147] [Evaluation of film heat resistance] After hardening and baking at 150°C, the underlayer film was further baked at 240°C for 120 seconds, and the film thickness reduction rate (%) was calculated from the difference in film thickness before and after baking, and the film heat resistance of each underlayer film was evaluated according to the evaluation criteria shown below.

[0148] <Evaluation criteria> S: Film thickness reduction rate before and after 400℃ baking ≦10% A: 10%<400℃ bake film thickness reduction rate≦15% B: 15%<400℃ bake film thickness reduction rate≦20% C: Film thickness reduction rate before and after 400℃ baking > 20%

[0149] [Evaluation of film etching resistance] First, a novolac underlayer film was prepared under the same conditions as in Example 1, except that novolac (PSM4357 manufactured by Gun-ei Chemical Co., Ltd.) was used instead of the lithography film-forming composition in Example 1, and the drying temperature was set to 110°C. The etching test shown below was then performed on this novolac underlayer film, and the etching rate was measured. Next, the etching test was similarly performed on underlayer films obtained from the lithography film-forming compositions of Examples 1 to 13 and Comparative Examples 1 and 2, and the etching rate was measured. The etching resistance of each underlayer film was evaluated according to the evaluation criteria shown below, using the etching rate of the novolac underlayer film as the standard. From a practical standpoint, the following S rating is particularly preferable, and A rating and B rating are preferred.

[0150] <Etching test> Etching equipment: Samco International RIE-10NR Output: 50W Pressure: 4Pa Time: 2 minutes Etching gas CF4 gas flow rate: O2 gas flow rate = 5:15 (sccm)

[0151] <Evaluation criteria> S: Etching rate is less than -30% compared to the novolac underlayer film A: The etching rate is between -30% and -20% compared to the novolac underlayer film. B: Etching rate is -20% or more to less than -10% compared to the novolac underlayer film C: The etching rate is -10% or more and 0% or less compared to the underlayer film of novolac

[0152] [Evaluation of embeddability in uneven substrates] The compositions for forming an underlayer film for lithography of Examples 1 to 13 and Comparative Examples 1 and 2 were applied to an 80-nm-thick SiO2 substrate with 60-nm lines and spaces, and baked for 60 seconds at 240° C. to form a 90-nm underlayer film. A cross section of the resulting film was cut out and observed with an electron microscope, and the embeddability into a stepped substrate was evaluated according to the following evaluation criteria.

[0153] <Evaluation criteria> A: The underlayer film is embedded without defects in the uneven parts of the 60nm line and space SiO2 substrate. C: There are defects in the uneven parts of the 60 nm line and space SiO2 substrate, and the underlayer film is not embedded.

[0154] [Evaluation of film flatness] Lithography underlayer film-forming compositions of Examples 1 to 10 and Comparative Examples 1 and 2 were each applied to a SiO2 stepped substrate containing a mixture of 100 nm wide, 150 nm pitch, and 150 nm deep trenches (aspect ratio: 1.5) and 5 μm wide, 180 nm deep trenches (open spaces). The resulting coating was then baked at 240°C for 120 seconds in an air atmosphere to form a 200 nm thick resist underlayer film. The shape of this resist underlayer film was observed with a scanning electron microscope (Hitachi High-Technologies Corporation's "S-4800"), and the difference (ΔFT) between the maximum and minimum film thicknesses of the resist underlayer film over the trenches or spaces was measured. The film flatness was evaluated according to the following criteria.

[0155] <Evaluation criteria> S: ΔFT<10nm (best flatness) A:10nm≦ΔFT<20nm (good flatness) B: 20nm≦ΔFT<40nm (fairly good flatness) C:40nm≦ΔFT (poor flatness)

[0156] The evaluation results of the above properties are summarized in Table 1. As is clear from Table 1, the film-forming compositions for lithography of Examples 1 to 13 containing an amine compound have high film-forming properties and solvent solubility, and are superior in curability, film heat resistance, film etching resistance, embeddability into uneven substrates, and film flatness compared to the film-forming compositions for lithography of Comparative Examples 1 and 2.

[0157] [Table 1]

[0158] Example 14 The lithography film-forming composition of Example 1 was applied to a 300 nm thick SiO2 substrate and baked at 150°C for 60 seconds and then at 240°C for 120 seconds to form an underlayer film with a thickness of 70 nm. An ArF resist solution was applied to this underlayer film and baked at 130°C for 60 seconds to form a photoresist layer with a thickness of 140 nm. The ArF resist solution used was prepared by blending 5 parts by mass of a compound of the following formula (R), 1 part by mass of triphenylsulfonium nonafluoromethanesulfonate, 2 parts by mass of tributylamine, and 92 parts by mass of PGMEA.

[0159] The compound of formula (R) below was prepared as follows: 4.15 g of 2-methyl-2-methacryloyloxyadamantane, 3.00 g of methacryloyloxy-γ-butyrolactone, 2.08 g of 3-hydroxy-1-adamantyl methacrylate, and 0.38 g of azobisisobutyronitrile were dissolved in 80 mL of tetrahydrofuran to form a reaction solution. This reaction solution was polymerized for 22 hours under a nitrogen atmosphere at a reaction temperature of 63°C, and then added dropwise to 400 mL of n-hexane. The resulting resin was coagulated and purified, and the resulting white powder was filtered and dried overnight under reduced pressure at 40°C to obtain the compound represented by formula (R) below.

[0160] [ka]

[0161] In formula (R), 40, 40, 20 indicate the ratio of each structural unit, and do not indicate a block copolymer.

[0162] The photoresist layer was then exposed to light using an electron beam lithography system (ELS-7500, 50 keV, manufactured by Elionix), baked at 115°C for 90 seconds (PEB), and developed in a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) for 60 seconds to obtain a positive resist pattern. The evaluation results for the resolution, sensitivity, and pattern shape of the obtained resist pattern are shown in Table 2.

[0163] Example 15 A positive resist pattern was obtained in the same manner as in Example 14, except that the composition for forming an underlayer film for lithography in Example 2 was used instead of the composition for forming an underlayer film for lithography in Example 1.

[0164] Example 16 A positive resist pattern was obtained in the same manner as in Example 14, except that the composition for forming an underlayer film for lithography in Example 3 was used instead of the composition for forming an underlayer film for lithography in Example 1.

[0165] Example 17 A positive resist pattern was obtained in the same manner as in Example 14, except that the composition for forming an underlayer film for lithography in Example 4 was used instead of the composition for forming an underlayer film for lithography in Example 1.

[0166] Example 18 A positive resist pattern was obtained in the same manner as in Example 14, except that the composition for forming an underlayer film for lithography in Example 5 was used instead of the composition for forming an underlayer film for lithography in Example 1.

[0167] (Comparative Example 3) A positive resist pattern was obtained in the same manner as in Example 14, except that the underlayer film formed using the composition for forming an underlayer film for lithography of Example 1 was not formed.

[0168] [Measurement and evaluation of resolution, sensitivity, and pattern shape] The resist patterns obtained in Examples 14 to 18 and Comparative Example 3 were measured for resolution and sensitivity as shown below, and the pattern shape after resolution was evaluated. The measurement and evaluation results are summarized in Table 2. As is clear from Table 2, Examples 14 to 18, which used the film-forming compositions for lithography of Examples 1 to 5 containing an aniline compound, were confirmed to have significantly superior resolution and sensitivity compared to Comparative Example 3. In addition, it was confirmed that the resist pattern shape after development was free of pattern collapse and had good rectangularity. Furthermore, the difference in the resist pattern shape after development indicated that the underlayer films of Examples 14 to 18 obtained from the film-forming compositions for lithography of Examples 1 to 5 had good adhesion to the resist material.

[0169] [Table 2]

[0170] As described above, the lithography film-forming material according to the present disclosure has high solvent solubility and is excellent in curability, film heat resistance, film etching resistance, embeddability into uneven substrates, and film flatness, making it suitable for wet processes. Therefore, lithography film-forming compositions containing the lithography film-forming material according to the present disclosure can be widely and effectively used in various applications requiring these properties. In particular, the present invention can be particularly effectively used in the fields of underlayer films for lithography and underlayer films for multilayer resists. This application is based on Japanese Patent Application No. 2021-032898, filed March 2, 2021, the contents of which are incorporated herein by reference.

Claims

1. Contains a compound having an amino group bonded to an aromatic ring, The underlayer film forming material for lithography, wherein the compound having an amino group bonded to an aromatic ring is a compound represented by the following formula (1A) and / or formula (1B): 【Chemistry 1】 (In formula (1A), X's each independently represent a single bond, —O—, —C(CH 3 ) 2 —, —CO—, or —COO—; A is a single bond, an oxygen atom, or one of the following structures: 【Chemistry 2】 Y is a single bond, —O—, —CH 2 —, —C(CH 3 ) 2 —, —C(CF 3 ) 2 —, 【Transformation 3】 and R 1 's each independently represent a group having 0 to 30 carbon atoms which may contain a heteroatom; Each m 1 is independently an integer of 0 to 4. 【Chemistry 4】 (In formula (1B), R 1' s each independently represent a group having 0 to 30 carbon atoms which may contain a heteroatom, and at least one of R 1' s is a hydroxymethyl group, a halooxymethyl group, or a methoxymethyl group; m 1' is an integer between 1 and 5. Underlayer film forming material for lithography.

2. A compound having an amino group bonded to an aromatic ring, The compound having an amino group bonded to an aromatic ring is at least one selected from the compounds represented by the following formulas (2), (3), and (4): Underlayer film forming material for lithography. 【Transformation 5】 (In formula (2), R 2 s each independently represent a group having 0 to 10 carbon atoms which may contain a heteroatom; m 2 's each independently represent an integer of 0 to 3; m 2' each independently represents an integer of 0 to 4; n is an integer between 1 and 4. 【Transformation 6】 (In formula (3), R 3 and R 4 each independently represent a group having 0 to 10 carbon atoms which may contain a heteroatom; m 3 is independently an integer of 0 to 4, m 4 is independently an integer of 0 to 4, n is an integer between 0 and 4. 【Transformation 7】 (In formula (4), R 5 s each independently represent a group having 0 to 10 carbon atoms which may contain a heteroatom; m5's each independently represent an integer of 1 to 4; n is an integer between 2 and 10.

3. 2. The material for forming an underlayer film for lithography according to claim 1, wherein the compound having an amino group bonded to an aromatic ring is a polymer of the formula (1A) and / or the formula (1B).

4. A is a single bond, an oxygen atom, or the following structure: 【Transformation 8】 Y is -C(CH 3 ) 2 - or - C(CF 3 ) 2 -is, The material for forming an underlayer film for lithography according to claim 1 or 3.

5. 5. The material for forming an underlayer film for lithography according to claim 1, wherein the heteroatom is selected from the group consisting of oxygen, fluorine, and silicon.

6. 6. The material for forming an underlayer film for lithography according to claim 1, further comprising a crosslinking agent.

7. 7. The material for forming an underlayer film for lithography according to claim 1, further comprising a crosslinking accelerator.

8. 8. The material for forming an underlayer film for lithography according to claim 1, further comprising a radical polymerization initiator.

9. A composition for forming an underlayer film for lithography, comprising the material for forming an underlayer film for lithography according to any one of claims 1 to 8 and a solvent.

10. The composition for forming an underlayer film for lithography according to claim 9 , further comprising an acid generator.

11. The composition for forming an underlayer film for lithography according to claim 9 or 10, further comprising a base generator.

12. An underlayer film for lithography formed using the composition for forming an underlayer film for lithography according to any one of claims 1 to 11.

13. A step of forming an underlayer film on a substrate using the composition for forming an underlayer film for lithography according to any one of claims 1 to 11; forming at least one photoresist layer on the underlayer film; irradiating predetermined areas of the photoresist layer with radiation and developing; A pattern forming method comprising:

14. A step of forming an underlayer film on a substrate using the composition for forming an underlayer film for lithography according to any one of claims 1 to 11; forming an intermediate layer film on the underlayer film using a resist intermediate layer film material containing silicon atoms; forming at least one photoresist layer on the intermediate layer film; irradiating predetermined areas of the photoresist layer with radiation and developing to form a resist pattern; a step of etching the intermediate layer film using the resist pattern as a mask to obtain an intermediate layer film pattern; a step of etching the underlayer film using the intermediate layer film pattern as an etching mask to obtain an underlayer film pattern; and a step of etching the substrate using the underlayer film pattern as an etching mask to form a pattern on the substrate; A pattern forming method comprising:

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