Polymer compound for forming resist underlayer film and composition for forming resist underlayer film containing the same

Abstract

The present invention provides a polymer compound for forming a resist underlayer film, which can reduce the appropriate exposure dose of a resist film without affecting the shape of the resist pattern film after development. According to one embodiment, the present invention provides a polymer compound for forming a resist underlayer film, which comprises a repeating unit represented by the general formula 1.

Description

[Technical Field]

[0001] The present invention relates to a polymer compound for forming a resist underlayer film and a composition for forming a resist underlayer film containing the same. [Background technology]

[0002] EUV (Extreme Ultra Violet) lithography is a technology that creates finer patterns to facilitate the high integration of semiconductor chips. The biggest difference between EUV lithography and existing ArF immersion argon fluoride (ArF), ArF (argon fluoride), and KrF (krypton fluoride) lithography is that it uses light with a wavelength of approximately 13.5 nm. As the wavelength of the light used becomes shorter, the photon energy becomes higher and it penetrates most elements, eliminating the need for a bottom anti-reflective coating, which was used in existing processes. However, since most EUV resist films do not have the necessary level of adhesion with the resist underlayer during mass production, research is ongoing to improve adhesion without anti-reflective properties.

[0003] Another issue that needs to be overcome with EUV lithography is the economics of the process, due to the high equipment and maintenance costs. Generally, the amount of light irradiated onto a resist film to form a desired pattern is set, and this is called the appropriate exposure dose.

[0004] While considerable research has been conducted to minimize the exposure dose of EUV resist films, simply reducing the exposure dose has presented problems such as reduced surface roughness and size uniformity of the resist pattern film. This reduced surface roughness and size uniformity of the resist pattern film leads to reduced product performance and lower yields. This phenomenon is known as the stochastic effect. Photons with a wavelength of 13.5 nm in the EUV process possess approximately 92 eV of energy, 18.4 times higher than the approximately 5 eV of photons used in conventional KrF lithography. As a result, the number of photons irradiated with the same exposure dose in the EUV process is significantly lower than in conventional processes, further exacerbating the stochastic effect. Research is ongoing to address this issue. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a polymeric compound for forming a resist underlayer film, which can reduce the appropriate exposure dose of a resist film without affecting the shape of the resist pattern film after development.

[0006] Another object of the present invention is to provide a composition for forming a resist underlayer film, which contains the polymer compound for forming a resist underlayer film.

[0007] The objects of the present invention are not limited to the objects mentioned above, and other objects and advantages of the present invention not mentioned above will be understood from the following description and will become more clearly understood from the examples of the present invention. Furthermore, it will be easily understood that the objects and advantages of the present invention can be realized by the means and combinations thereof as claimed. [Means for solving the problem]

[0008] In order to achieve the above object, according to a first aspect of the present invention, there is provided a polymer compound for forming a resist underlayer film, which comprises a repeating unit represented by the following general formula 1: [General formula 1] JPEG2025540968000001.jpg49170

[0009] Specifically, in the general formula 1, R0 is a hydrogen atom; or a linear or branched alkyl group having 1 to 4 carbon atoms; R1, R2, R3, R4, and R5 are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a halogen atom, or a hydroxy group; and at least one of R1, R2, R3, R4, and R5 is a halogen atom, and at least one of them is a hydroxy group.

[0010] According to the second aspect of the present invention, in the first aspect, four selected from R1, R2, R3, R4, and R5 may include a halogen atom, and specifically may be composed of a halogen atom.

[0011] According to a third aspect of the present invention, in the first or second aspect, the halogen atom may be a fluorine atom or an iodine atom.

[0012] According to a fourth aspect of the present invention, there can be provided a polymer compound for forming a resist underlayer film according to any one of the first to third aspects, further comprising a repeating unit derived from an unsaturated compound having one or more crosslinking reactive functional groups at one end.

[0013] According to a fifth aspect of the present invention, in the fourth aspect, the crosslinking reactive functional group may be a hydroxy group or a thiol group.

[0014] According to a sixth aspect of the present invention, in the fourth or fifth aspect, the unsaturated compound may be an acrylic compound.

[0015] According to a seventh aspect of the present invention, there is provided a polymer compound for forming a resist underlayer film according to any one of the first to sixth aspects, further comprising a repeating unit represented by the following general formula 2: [General formula 2] JPEG2025540968000002.jpg57170

[0016] In the general formula 2, R6 is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and A is a substituted or unsubstituted linear saturated hydrocarbon linking group having 2 to 12 carbon atoms; a substituted or unsubstituted linear unsaturated hydrocarbon linking group having 3 to 12 carbon atoms and containing one or more unsaturated bonds; or a substituted or unsubstituted ring linking group having 3 to 12 carbon atoms.

[0017] According to an eighth aspect of the present invention, in the seventh aspect, the molar ratio of the repeating unit represented by the general formula 1 to the repeating unit represented by the general formula 2 (general formula 1:general formula 2) may be 50:50 or more and 100:0 or less.

[0018] According to a ninth aspect of the present invention, in any one of the first to eighth aspects, in the general formula 1, the ratio of hydroxy groups to halogen atoms (hydroxy groups:halogen atoms) may be 1:1 to 1:4.

[0019] According to a tenth aspect of the present invention, there is provided a composition for forming a resist underlayer film, comprising the polymer compound for forming a resist underlayer film according to any one of the first to ninth aspects and a solvent.

[0020] According to an eleventh aspect of the present invention, in the tenth aspect, the content of the polymer compound for forming a resist underlayer film may be 0.02 to 1.00 wt % based on the total weight of the composition for forming a resist underlayer film.

[0021] According to a twelfth aspect of the present invention, there can be provided a composition for forming a resist underlayer film according to the tenth or eleventh aspect, further comprising at least one of a crosslinking agent and a thermal acid generator.

[0022] The above summary of the invention is not an exhaustive list of the features of the invention, and the various features and advantages thereof will be more fully understood with reference to the following specific examples. [Effects of the Invention]

[0023] According to one aspect of the present invention, it is possible to provide a polymer compound for forming a resist underlayer film, which can maintain the same roughness and size of a resist pattern film even at an exposure dose lower than the appropriate exposure dose for the resist film, due to the influence of secondary electrons generated by increasing the photon absorption rate of the resist underlayer film.

[0024] In addition to the above-mentioned effects, specific effects of the present invention will be described below while explaining specific details for carrying out the invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] In this specification, the singular expression includes the plural expression unless the context clearly indicates otherwise.

[0026] When various embodiments are described in this specification, the effects of the present invention can be defined to include not only the effects attributable to each embodiment itself, but also the effects resulting from the organic combination of each embodiment. For example, even if Embodiments 1 and 2 are described independently in this specification, the effects resulting from the organic combination of Embodiments 1 and 2 are also included in the effects of the present invention, unless the context clearly indicates otherwise.

[0027] As used herein, terms such as "about" or "substantially" refer to a reasonable amount of deviation from the modified term so as not to significantly change the end result. Such terms can be interpreted to include a deviation of at least ±5% or at least ±10%, within the limits where such deviation does not alter or invalidate the meaning of the word.

[0028] In this specification, a numerical range indicated using the term "to" indicates a numerical range that includes the values ​​described before and after the term as the lower and upper limits, respectively. When multiple numerical values ​​are disclosed as the upper and lower limits of a given numerical range, the numerical range disclosed in this specification can be understood as any numerical range in which any one of the multiple lower limits and any one of the multiple upper limits are the lower and upper limits, respectively. For example, when a to b or c to d are described in the specification, this can be understood to mean a to b, a to d, c to d, or c to b.

[0029] As used herein, "containing at least one of a, b, and c" means containing a, b, or c alone, or a combination of two or more selected from the group consisting of a, b, and c.

[0030] As used herein, the term "substituted" can be defined as at least one or more hydrogen atoms being replaced with any one selected from the group consisting of a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, an amine group, a sulfide group, a thiol group, an alkoxy group, an acetoxy group, a nitrile group, an aldehyde group, an ether group, an ester group, an acetal group, a ketone group, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, a heterocycloalkyl group, an allyl group, an aryl group, a heteroaryl group, derivatives thereof, and combinations thereof.

[0031] As used herein, the term "layer" or "film" refers to a layer or film that covers the entire area of ​​the observed region, as well as a layer or film that covers only a portion of the observed region. For example, the surface of a layer or film can be defined as having a flat, non-flat, or a combination thereof; or a continuous, discontinuous, or a combination thereof. For example, when a layer or film is formed directly on another component, the coverage of the surface of the other component with respect to the surface of the first component can be defined as 1% or more, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 85% or more, 90% or more, 95% or more, or 99% or more.

[0032] In this specification, "weight average molecular weight" or "number average molecular weight" refers to a molecular weight in terms of standard polystyrene, and can be analyzed using a gel permeation chromatography (GPC) device. Here, the GPC analysis method can use tetrahydrofuran as a developing solvent, and may be performed under the following analytical conditions: a sample concentration of 5 mg / mL, a sample introduction amount of 100 μL, a temperature of 40° C., and a flow rate of 1 mL / min.

[0033] According to one aspect of the present invention, there is provided a polymer compound for forming a resist underlayer film, which comprises a repeating unit represented by the following general formula 1: [General formula 1] JPEG2025540968000003.jpg49170

[0034] Specifically, in the general formula 1, R0 is a hydrogen atom; or a linear or branched alkyl group having 1 to 4 carbon atoms; R1, R2, R3, R4, and R5 are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a halogen atom, or a hydroxy group; and at least one of R1, R2, R3, R4, and R5 is a halogen atom, and at least one of them is a hydroxy group.

[0035] The resist underlayer film is primarily introduced to improve the adhesion of the resist, and the appropriate exposure dose for forming the desired resist pattern may vary depending on the composition of the resist underlayer film. For example, simply reducing the exposure dose of the resist film can result in problems such as reduced surface roughness and size uniformity of the resist pattern film. According to one aspect of the present invention, in the repeating unit represented by General Formula 1, at least one of R1, R2, R3, R4, and R5 is a halogen atom, and the other contains a hydroxy group. This allows the halogen atom to facilitate EUV photon absorption in the resist underlayer film, increasing the generation of secondary electrons, and then smoothly transmitting the generated secondary electrons to the upper resist film via the hydroxy group. Even if a hydroxy group is substituted in the repeating unit of General Formula 1, if the halogen atom is not substituted, the generation of secondary electrons cannot be sufficiently increased, which can result in a problem of not being able to sufficiently reduce the appropriate exposure dose of the resist film. Even if a halogen atom is substituted on the repeating unit represented by general formula 1, if a hydroxy group is not substituted, secondary electrons generated by the halogen atom cannot be smoothly transmitted to the overlying resist film, and the appropriate exposure dose of the resist film may worsen rather than improve. That is, according to one aspect of the present invention, when the substituent on the repeating unit represented by general formula 1 is composed of a combination of a hydroxy group and a halogen atom, it is possible to provide a polymer compound for forming a resist underlayer film, which can maintain the same roughness and size of the resist pattern film even at an exposure dose lower than the appropriate exposure dose of the resist film due to the influence of the secondary electrons generated by increasing the photon absorption rate of the resist underlayer film. The configuration of the present invention will be described in more detail below.

[0036] 1. Polymer compounds for forming resist underlayer films The polymer compound for forming a resist underlayer film according to the present invention contains a repeating unit represented by the following general formula 1: [General formula 1] JPEG2025540968000004.jpg49170

[0037] Specifically, in the general formula 1, R0 may be a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, more specifically a hydrogen atom or a linear or branched alkyl group having 1 to 3 carbon atoms, and even more specifically a hydrogen atom or an alkyl group having 1 to 2 carbon atoms. In the general formula 1, when the number of carbon atoms in R0 is within the above range, it is possible to provide an advantage that the molar concentration of the repeating unit represented by the general formula 1 can be easily increased during the synthesis of a polymer compound.

[0038] Specifically, in the general formula 1, R1, R2, R3, R4, and R5 are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a halogen atom, or a hydroxy group, and at least one of R1, R2, R3, R4, and R5 is a halogen atom and at least one is a hydroxy group. When at least one of R1, R2, R3, R4, and R5 in the repeating unit represented by the general formula 1 is a halogen atom and the other is a hydroxy group, the halogen atom facilitates EUV photon absorption in the resist underlayer film, increasing the generation of secondary electrons, and the generated secondary electrons can then be smoothly transferred to the upper resist film via the hydroxy group. Even if a hydroxy group is substituted into the repeating unit of the general formula 1, if a halogen atom is not substituted, the generation of secondary electrons cannot be sufficiently increased, and the appropriate exposure dose of the resist film cannot be sufficiently reduced. Even if a halogen atom is substituted in the repeating unit represented by the general formula 1, if a hydroxy group is not substituted, secondary electrons generated by the halogen atom cannot be smoothly transferred to the upper resist film, and the proper exposure amount of the resist film may be deteriorated rather than improved.

[0039] According to one embodiment of the present invention, the number of halogen atoms in R1, R2, R3, R4, and R5 may be 4. When the number of halogen atoms in R1, R2, R3, R4, and R5 is 4, the EUV photon absorption of the resist underlayer film can be further facilitated, thereby increasing the generation of secondary electrons. As a result, the appropriate exposure dose of the resist film can be sufficiently reduced.

[0040] According to one embodiment of the present invention, the halogen atom may be a fluorine atom or an iodine atom, and more specifically, may be an iodine atom. According to one embodiment of the present invention, when the halogen atom is a fluorine atom or an iodine atom, generation of etching gas can be more effectively prevented than with other halogen atoms. Meanwhile, iodine atoms have high absorbance to an EUV light source, and can further reduce the appropriate exposure dose of the resist film compared to fluorine atoms.

[0041] According to another embodiment of the present invention, the polymer compound for forming a resist underlayer film may further include a repeating unit derived from an unsaturated compound having one or more crosslinking functional groups at one end. Specifically, the crosslinking functional group may be a functional group having high reactivity to form a chemical bond with a crosslinking agent. The unsaturated compound may be a compound having an unsaturated bond such as a carbon-carbon double bond (C=C). Specifically, the unsaturated compound having one or more crosslinking functional groups at one end may increase the degree of crosslinking during the formation of the resist underlayer film, thereby mitigating the phenomenon of resist pattern collapse during the formation of a line and space pattern, etc.

[0042] Specifically, the cross-linking reactive functional group may be a hydroxy group or a thiol group, and more specifically, may be a hydroxy group.

[0043] Specifically, the unsaturated compound may be an acrylic compound, such as, but not limited to, hydroxyethyl methacrylate, 4-hydroxyphenyl methacrylate, or 3-hydroxyadamantan-1-yl methacrylate.

[0044] According to still another embodiment of the present invention, the polymer compound for forming a resist underlayer film may further include a repeating unit represented by the following general formula 2: [General formula 2] JPEG2025540968000005.jpg57170

[0045] In the general formula 2, R6 may be a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, specifically a linear or branched alkyl group having 1 to 3 carbon atoms, more specifically an alkyl group having 1 to 2 carbon atoms. When the carbon number of R6 is within the above range, the molar concentration of the repeating unit represented by the general formula 2 can be easily adjusted during the synthesis of the polymer.

[0046] In the general formula 2, A may be a substituted or unsubstituted linear saturated hydrocarbon linking group having 2 to 12 carbon atoms; a substituted or unsubstituted linear unsaturated hydrocarbon linking group having 3 to 12 carbon atoms and containing one or more unsaturated bonds; or a substituted or unsubstituted cyclic linking group having 3 to 12 carbon atoms. Specifically, the linear saturated hydrocarbon linking group may be a linear linking group consisting of a carbon-carbon single bond, such as -CH-CH- or -CH-CH-CH-. The linear unsaturated hydrocarbon linking group may be a linking group containing at least one of a carbon-carbon double bond and a triple bond, such as -HC=CH-CH-. The cyclic linking group may be a linking group containing at least one of an aliphatic ring and an aromatic ring, such as a benzene ring linking group or a multi-ring linking group. In this specification, the term "substituted" can be defined as at least one hydrogen atom being substituted with a heteroatom or a functional group containing a heteroatom. For example, the heteroatom-containing functional group may be a hydroxy group, an amine group, an ester group, an ether group, an alkoxy group, a thiol group, a ketone group, or the like.

[0047] According to yet another embodiment of the present invention, the polymer compound for forming a resist underlayer film may be composed of a repeating unit represented by General Formula 1. By being composed of a repeating unit represented by General Formula 1, the polymer compound for forming a resist underlayer film can further reduce the appropriate exposure dose of the resist film without affecting the pattern shape of the resist film.

[0048] According to yet another embodiment of the present invention, the molar ratio of the repeating units represented by General Formula 1 to the repeating units represented by General Formula 2 (General Formula 1:General Formula 2) may be 50:50 or more and 100:0 or less, or 50:50 or more and less than 100:0, specifically 80:20 or more and 100:0 or less, or 80:20 or more and less than 100:0. When the molar ratio of the repeating units represented by General Formula 1 to the repeating units represented by General Formula 2 is 100:0, the polymer compound according to the present invention is a compound consisting solely of repeating units represented by General Formula 1. When the molar ratio of the repeating units represented by General Formula 1 to the repeating units represented by General Formula 2 satisfies the above molar ratio range or when the polymer compound according to the present invention consists solely of repeating units represented by General Formula 1, the appropriate exposure dose of the resist film can be further reduced without affecting the pattern shape of the resist film. For example, the molar ratio of the repeating units represented by General Formulas 1 and 2 is 1 It can be analyzed by H-NMR.

[0049] According to yet another embodiment of the present invention, the ratio of hydroxy groups to halogen atoms (hydroxy groups:halogen atoms) in General Formula 1 may be 1:1 to 1:4, specifically 1:2 to 1:4. When the ratio of hydroxy groups to halogen atoms in General Formula 1 satisfies the above numerical range, the appropriate exposure dose of the resist film can be further reduced without affecting the pattern shape of the resist film. For example, the ratio of hydroxy groups to halogen atoms in General Formula 1 can be analyzed by NMR or an elemental content analysis method.

[0050] The weight average molecular weight (M w) may be 1,500 to 50,000 g / mol, specifically 3,000 to 10,000 g / mol. When the weight-average molecular weight of the polymer compound for forming a resist underlayer film satisfies the above numerical range, the resist underlayer film produced is not partially dissolved by the solvent in the resist composition, and at the same time, has an appropriate level of solubility in the solvent of the resist underlayer film composition, and the etching rate of the resist underlayer film in a dry etching process can reach an appropriate level.

[0051] 2. Composition for forming resist underlayer film Another embodiment of the present invention provides a composition for forming a resist underlayer film, comprising the polymer compound for forming a resist underlayer film, and a solvent. The repeated descriptions of the above-mentioned parts will be briefly explained or omitted.

[0052] The content of the polymer compound for forming a resist underlayer film according to the present invention may be 0.02 to 1.00 wt %, specifically 0.02 to 0.50 wt %, based on the total weight of the composition for forming a resist underlayer film. When the content of the polymer compound for forming a resist underlayer film satisfies the above numerical range, the formation of a resist underlayer film is facilitated, a resist underlayer film having an appropriate thickness is realized, and the shape of an upper resist film can be sufficiently transferred.

[0053] The solvent according to the present invention may be an organic solvent commonly used in compositions for forming resist underlayer films, for example, any one selected from the group consisting of cyclohexanone, cyclopentanone, butyrolactone, dimethylacetamide, dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone (NMP), tetrahydrofurfural alcohol, propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), ethyl lactate, methyl 2-hydroxyisobutyrate (HBM), and mixtures thereof. According to one example, the content of the organic solvent may be the remainder excluding the polymer compound for forming a resist underlayer film, a crosslinking agent and a thermal acid generator, which will be described later, based on the total weight of the composition for forming a resist underlayer film; or the remainder excluding the polymer compound for forming a resist underlayer film, a crosslinking agent, a thermal acid generator and additives.

[0054] The composition for forming a resist underlayer film according to the present invention may further contain at least one of a crosslinking agent and a thermal acid generator.

[0055] The crosslinking agent according to the present invention can promote a crosslinking reaction between polymer compounds for forming a resist underlayer film. Specifically, the content of the crosslinking agent may be 0.005 to 1.0 wt %, more specifically 0.02 to 0.10 wt %, based on the total weight of the composition for forming a resist underlayer film. When the content of the crosslinking agent satisfies the above numerical range, a resist underlayer film can be easily formed. For example, the crosslinking agent may correspond to one selected from the group consisting of melamine-based crosslinking agents having a crosslinking substituent such as a methylol group or a methoxymethyl group, epoxy-based crosslinking agents, and combinations thereof. Typical examples include MX-270, MX-279, MX-280, and MW-390 manufactured by Sanwa Chemical Co., Ltd. The melamine-based crosslinking agent may correspond to one selected from the group consisting of hexamethylolmelamine, hexamethoxymethylmelamine, a compound in which 1 to 5 methylol groups of hexamethylolmelamine are methoxymethylated, hexamethoxyethylmelamine, hexaacyloxymethylmelamine, and a compound in which 1 to 5 methylol groups of hexamethylolmelamine are acyloxymethylated. The epoxy-based crosslinking agent may correspond to a substance having an epoxy group and having crosslinking properties.For example, the epoxy-based crosslinking agent may be a divalent glycidyl group-containing low molecular weight compound such as bisphenol A glycidyl ether, ethylene glycol diglycidyl ether, butanediol diglycidyl ether, hexanediol diglycidyl ether, dihydroxybiphenyl diglycidyl ether, phthalic acid diglycidyl ester, or N,N-diglycidylaniline; a trivalent glycidyl group-containing low molecular weight compound such as trimethylolpropane triglycidyl ether, trimethylolphenol triglycidyl ether, or TrisP-PA triglycidyl ether; a pentaerythritol glycidyl ether; The glycidyl group-containing polymer may include at least one selected from the group consisting of tetravalent glycidyl group-containing low molecular weight compounds such as dipentaerythritol tetraglycidyl ether and tetramethylol bisphenol A tetraglycidyl ether, polyvalent glycidyl group-containing low molecular weight compounds such as dipentaerythritol pentaglycidyl ether and dipentaerythritol hexaglycidyl ether, and glycidyl group-containing polymer compounds such as polyglycidyl (meth)acrylate and 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol.

[0056] The thermal acid generator according to the present invention can promote the crosslinking reaction of a polymer compound for forming a resist underlayer film. The thermal acid generator may be a conventional thermal acid generator that promotes crosslinking reactions, such as an ammonium salt compound, a sulfonium salt compound, an iodonium salt compound, or a mixture thereof. Examples of the thermal acid generator include triethylammonium nonaflate, triphenylsulfonium nonaflate, dodecyl benzenesulfonic acid, and para-toluene sulfonic acid. Specifically, the content of the thermal acid generator may be 0.001 to 0.5 wt %, more specifically 0.005 to 0.10 wt %, based on the total weight of the composition for forming a resist underlayer film. When the content of the thermal acid generator is within the above range, the resist film can be easily formed and at the same time, generation of fumes during the heating process can be prevented.

[0057] If necessary, the composition for forming a resist underlayer film according to the present invention may further contain an additive. Specifically, the additive may be one selected from the group consisting of an adhesion promoter, a surfactant, a rheology modifier, and a mixture thereof. The content of the additive may be appropriately changed.

[0058] The adhesion promoter can be added to improve the adhesion of the resist underlayer film to the substrate or resist film, particularly to prevent the resist film from peeling off during development. Examples of the adhesion promoter include chlorosilanes such as trimethylchlorosilane, dimethylvinylchlorosilane, methyldiphenylchlorosilane, and chloromethyldimethylchlorosilane; alkoxysilanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethylvinylethoxysilane, diphenyldimethoxysilane, and phenyltriethoxysilane; silazanes such as hexamethyldisilazane, N,N'-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine, and trimethylsilylimidazole; vinyltrichlorosilanes such as methyltrichlorosilane, methylvinyldimethoxysilane, methyltrichloro ... silanes such as methylsilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-glycidoxypropyltrimethoxysilane; heterocyclic compounds such as benzotriazole, benzimidazole, indazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, urazole, thiouracil, mercaptoimidazole, and mercaptopyrimidine; or ureas such as 1,1-dimethylurea and 1,3-dimethylurea, or thiourea compounds.

[0059] The surfactant can be added to prevent pinholes and striations from occurring and to further improve the coating properties for surface stains. Examples of the surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkylaryl ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether; polyoxyethylene-polyoxypropylene block copolymers; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate; nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate; EFTOP EF301, EF303, and EF352 (manufactured by Tohkem Products Corporation); At least one selected from the group consisting of fluorosurfactants such as F171 and F173 (manufactured by Dainippon Ink and Chemicals, Inc.), FLUORAD FC430 and FC431 (manufactured by Sumitomo 3M Limited.), ASAHI GUARD AG710, SURFLON S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (manufactured by Asahi Glass Co., Ltd.), and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can be used.

[0060] The rheology adjuster can be added to improve the fluidity of the resist underlayer film composition. Examples of the rheology adjuster include phthalic acid derivatives such as dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, and butyl isodecyl phthalate, adipic acid derivatives such as di-n-butyl adipate, diisobutyl adipate, diisooctyl adipate, and octyldecyl adipate, maleic acid derivatives such as di-n-butyl maleate, diethyl maleate, and dinonyl maleate, oleic acid derivatives such as methyl oleate, butyl oleate, and tetrahydrofurfuryl oleate, and stearic acid derivatives such as n-butyl stearate and glyceryl stearate.

[0061] The resist underlayer film according to the present invention is obtained by curing the composition for forming a resist underlayer film.

[0062] The method for producing a resist underlayer film according to the present invention may include the steps of applying the composition for forming a resist underlayer film to an upper portion of a layer to be etched, such as a silicon wafer or an aluminum substrate, and crosslinking the applied composition.

[0063] For example, the step of applying the composition for forming a resist underlayer film may be performed by a conventional method such as spin coating, roller coating, or spraying, and the step of crosslinking the applied composition for forming a resist underlayer film may be performed by heating the applied composition using a device such as a hot plate or a convection oven. For example, the crosslinking step may be performed at a temperature of 90 to 240°C. When the temperature is within this range, the solvent can be sufficiently removed and the crosslinking reaction can be sufficiently carried out.

[0064] Hereinafter, the embodiments of the present invention will be described in detail so that a person having ordinary skill in the art to which the present invention pertains can easily implement the present invention. However, this is merely an example, and the scope of the present invention is not limited by the following content.

[0065] [Synthesis example: Synthesis of polymer compounds for forming resist underlayer films] <Example 1: Synthesis example of compound represented by chemical formula 1> A 250 mL reactor was charged with 40 g of 2-butanone and heated to 85°C. Then, 17.15 g of 3-fluoro-4-hydroxyphenyl methacrylate, 2.85 g of hydroxyethyl methacrylate, and 2.01 g of dimethyl 2,2'-azobis(2-methylpropionate) were added dropwise to a solution of 40 g of 2-butanone for 6 hours. After refluxing for 12 hours, the temperature was lowered to room temperature to terminate the polymerization reaction. After evaporating the 2-butanone using a rotary evaporator, 40 g of ethyl acetate was added. 40 g of deionized water was added, stirred, and then allowed to stand to separate the layers. After removing the lower aqueous layer, 40 g of deionized water was added again, stirred, and then allowed to stand to separate the layers. After removing the lower aqueous layer, the solvent was removed using a rotary evaporator, and the resulting solvent-removed product was dissolved in 180 g of tetrahydrofuran. The solution thus prepared was added dropwise to 2 kg of heptane, and the resulting precipitate was filtered to synthesize the compound represented by the following formula 1.

[0066] 1 As a result of confirmation by 1 H-NMR, the molar ratio of each repeating unit in the compound represented by the following chemical formula 1 is m:n=80:20. [ka]

[0067] <Example 2: Synthesis example of compound represented by chemical formula 2> A compound represented by the following chemical formula 2 was synthesized in the same manner as in Example 1, except that 17.15 g of 3-fluoro-5-hydroxyphenyl methacrylate was used instead of 17.15 g of 3-fluoro-4-hydroxyphenyl methacrylate.

[0068] 1 As a result of confirmation by 1 H-NMR, the ratio of the repeating units in the compound represented by the following chemical formula 2 was m:n=80:20. [ka]

[0069] <Example 3: Synthesis example of compound represented by chemical formula 3> A compound represented by the following chemical formula 3 was synthesized in the same manner as in Example 1, except that 17.15 g of 3-fluoro-2-hydroxyphenyl methacrylate was used instead of 17.15 g of 3-fluoro-4-hydroxyphenyl methacrylate.

[0070] 1 As a result of confirmation by 1 H-NMR, the molar ratio of each repeating unit in the compound represented by the following chemical formula 3 was m:n=80:20. [ka]

[0071] <Example 4: Synthesis example of compound represented by chemical formula 4> A compound represented by the following chemical formula 4 was synthesized in the same manner as in Example 1, except that 18.07 g of 3-hydroxy-2-iodophenyl methacrylate was used instead of 17.15 g of 3-fluoro-4-hydroxyphenyl methacrylate, 1.93 g of hydroxyethyl methacrylate was used instead of 2.85 g, and 1.37 g of dimethyl 2,2′-azobis(2-methylpropionate) was used instead of 2.01 g.

[0072] 1 As a result of confirmation by 1 H-NMR, the molar ratio of each repeating unit in the compound represented by the following chemical formula 4 is m:n=80:20. [ka]

[0073] <Example 5: Synthesis example of compound represented by chemical formula 5> A compound represented by the following chemical formula 5 was synthesized in the same manner as in Example 1, except that 13.16 g of 2,3,5,6-Tetrafluoro-4-hydroxyphenyl methacrylate was used instead of 17.15 g of 3-Fluoro-4-hydroxyphenyl methacrylate, 6.84 g of hydroxyethyl methacrylate was used instead of 2.85 g, and 1.94 g of dimethyl 2,2′-azobis(2-methylpropionate) was used instead of 2.01 g.

[0074] 1 As a result of confirmation by 1 H-NMR, the molar ratio of each repeating unit in the compound represented by the following chemical formula 5 is m:n=50:50. [ka]

[0075] <Example 6: Synthesis example of compound represented by chemical formula 6> A compound represented by the following chemical formula 6 was synthesized in the same manner as in Example 1, except that 17.70 g of 2,3,5,6-Tetrafluoro-4-hydroxyphenyl methacrylate was used instead of 17.15 g of 3-Fluoro-4-hydroxyphenyl methacrylate, 2.30 g of hydroxyethyl methacrylate was used instead of 2.85 g, and 1.63 g of dimethyl 2,2′-azobis(2-methylpropionate) was used instead of 2.01 g.

[0076] 1 As a result of confirmation by 1 H-NMR, the molar ratio of each repeating unit in the compound represented by the following chemical formula 6 is m:n=80:20. [ka]

[0077] <Example 7: Synthesis example of compound represented by chemical formula 7> A compound represented by the following chemical formula 7 was synthesized in the same manner as in Example 1, except that 20.00 g of 2,3,5,6-Tetrafluoro-4-hydroxyphenyl methacrylate was used instead of 17.15 g of 3-Fluoro-4-hydroxyphenyl methacrylate, 1.47 g of dimethyl 2,2′-azobis(2-methylpropionate) was used instead of 2.01 g, and 2.85 g of hydroxyethyl methacrylate was not used.

[0078] 1 As a result of confirmation by H-NMR, the molar ratio of the compound represented by the following chemical formula 7 is m=100. [ka]

[0079] <Example 8: Synthesis example of compound represented by chemical formula 8> A compound represented by the following chemical formula 8 was synthesized in the same manner as in Example 1, except that 16.98 g of 2,3,5,6-tetrafluoro-4-hydroxyphenyl methacrylate was used instead of 17.15 g of 3-fluoro-4-hydroxyphenyl methacrylate, 3.02 g of 4-hydroxyphenyl methacrylate was used instead of 2.85 g of hydroxyethyl methacrylate, and 1.56 g of dimethyl 2,2′-azobis(2-methylpropionate) was used instead of 2.01 g.

[0080] 1 As a result of confirmation by 1 H-NMR, the molar ratio of each repeating unit in the compound represented by the following chemical formula 8 is m:n=80:20. [ka]

[0081] <Example 9: Synthesis example of compound represented by chemical formula 9> A compound represented by the following chemical formula 9 was synthesized in the same manner as in Example 1, except that 16.18 g of 2,3,5,6-tetrafluoro-4-hydroxyphenyl methacrylate was used instead of 17.15 g of 3-fluoro-4-hydroxyphenyl methacrylate, 3.82 g of 3-hydroxyadamantan-1-yl methacrylate was used instead of 2.85 g of hydroxyethyl methacrylate, and 1.49 g of dimethyl 2,2′-azobis(2-methylpropionate) was used instead of 2.01 g.

[0082] 1 As a result of confirmation by 1 H-NMR, the molar ratio of each repeating unit in the compound represented by the following chemical formula 9 is m:n=80:20. [ka]

[0083] <Comparative Example 1: Compound represented by Chemical Formula 10> A compound represented by the following chemical formula 10 was synthesized by the method described in Preparation Example 4 of Korean Patent Publication No. 10-2017-0014120. n in the following chemical formula 10 is 5. [ka]

[0084] <Comparative Example 2: Synthesis example of compound represented by chemical formula 11> A compound represented by the following chemical formula 11 was synthesized in the same manner as in Example 1, except that 16.91 g of 4-hydroxyphenyl methacrylate was used instead of 17.15 g of 3-fluoro-4-hydroxyphenyl methacrylate, 3.09 g of hydroxyethyl methacrylate was used instead of 2.85 g, and 2.19 g of dimethyl 2,2′-azobis(2-methylpropionate) was used instead of 2.01 g.

[0085] 1 As a result of confirmation by 1 H-NMR, the molar ratio of each repeating unit in the compound represented by the following chemical formula 11 is m:n=80:20. [ka]

[0086] <Comparative Example 3: Synthesis example of compound represented by chemical formula 12> A compound represented by the following chemical formula 12 was synthesized in the same manner as in Example 1, except that 17.50 g of 6-hydroxynaphthyl methacrylate was used instead of 17.15 g of 3-fluoro-4-hydroxyphenyl methacrylate, 2.50 g of hydroxyethyl methacrylate was used instead of 2.85 g, and 1.77 g of dimethyl 2,2′-azobis(2-methylpropionate) was used instead of 2.01 g.

[0087] 1As a result of confirmation by 1 H-NMR, the molar ratio of each repeating unit in the compound represented by the following chemical formula 12 was m:n=80:20. [ka]

[0088] <Comparative Example 4: Synthesis example of compound represented by chemical formula 13> A compound represented by the following chemical formula 13 was synthesized in the same manner as in Example 1, except that 17.71 g of pentafluorophenyl methacrylate was used instead of 17.15 g of 3-fluoro-4-hydroxyphenyl methacrylate, 2.29 g of hydroxyethyl methacrylate was used instead of 2.85 g, and 1.62 g of dimethyl 2,2′-azobis(2-methylpropionate) was used instead of 2.01 g.

[0089] 1 As a result of confirmation by 1 H-NMR, the molar ratio of each repeating unit in the compound represented by the following chemical formula 13 was m:n=80:20. [ka]

[0090] [Production Example 1: Production of composition for forming resist underlayer film] A solution was prepared by mixing 0.47 g of each polymer compound synthesized by the method according to Examples 1 to 9 and Comparative Examples 1 to 4, 0.14 g of tetrabutoxymethylglycoluril (NIKALAC MX-279, Sanwa Chemical Co., Ltd.) acting as a crosslinker, 0.03 g of triethylammonium nonaflate acting as a thermal acid generator, and 299.36 g of methyl 2-hydroxyisobutyrate acting as a solvent. The prepared solution was filtered using a microfilter with a pore size of 0.45 μm to prepare compositions for forming resist underlayer films according to Examples 1 to 9 and Comparative Examples 1 to 4, respectively.

[0091] [Experimental example: Evaluation of proper exposure and uniformity of circular patterns] The appropriate exposure dose and uniformity of the circular pattern for the composition for forming a resist underlayer film produced by the method according to Production Example 1 were evaluated by the following methods.

[0092] 1) Proper exposure Each of the compositions for forming a resist underlayer film prepared by the method of Preparation Example 1 was spin-coated on a silicon wafer and then baked at 205°C for 60 seconds to form a resist underlayer film having a thickness of 50 Å.

[0093] An EUV resist composition (CAR type positive EUV photoresist) was coated on the formed resist underlayer film to a thickness of 500 Å and soft-baked at 130°C for 60 seconds. Then, it was exposed using an EUV exposure tool (ASML, NXE3300) with an exposure mask having a hexagonally arranged hole pattern, and post-baked at 110°C for 60 seconds.

[0094] The resist was then developed with a 2.38 wt% aqueous solution of tetramethylammonium hydroxide (TMAH) to form a hexagonally arranged hole pattern with a diameter of 26 nm. The resist pattern film formed by this process was observed using a scanning electron microscope to confirm the optimum exposure dose for forming a hole with a diameter of 26 nm. In this case, a lower optimum exposure dose means improved productivity and yield.

[0095] 2) Uniformity evaluation of circular patterns The hole circularity, which is the uniformity of the circular pattern of 150 holes in a resist pattern film irradiated with an energy similar to the appropriate exposure dose, was measured using a CG-6300 (Hitachi) SEM. Specifically, the hole circularity is a numerical representation of the roundness of the holes, and the lower the value, the better the uniformity of the circular pattern.

[0096] [Table 1]

[0097] Comparing Example 1 and Comparative Examples 2 to 4 in Table 1 from the perspective of the substituents of the repeating unit represented by General Formula 1, it can be inferred that when at least one of R1, R2, R3, R4, and R5 in the repeating unit represented by General Formula 1 is a halogen atom and the other is a hydroxy group, the halogen atom facilitates EUV photon absorption in the resist underlayer film, increasing the generation of secondary electrons, and then the generated secondary electrons can be smoothly transferred to the upper resist film via the hydroxy group. This suggests that an effect similar to that achieved when a high exposure dose is applied is achieved. For example, in Comparative Examples 2 and 3, the repeating unit represented by General Formula 1 is not substituted with a halogen atom, which prevents a sufficient increase in secondary electron generation, and therefore the appropriate exposure dose of the resist film is not sufficiently low. As another example, in Comparative Example 4, the repeating unit represented by General Formula 1 is not substituted with a hydroxy group, which prevents the generated secondary electrons from being smoothly transferred to the upper resist film, and therefore the appropriate exposure dose of the resist film is very high.

[0098] In Table 1, by comparing Examples 5 to 7 from the viewpoint of the molar ratio of the repeating unit represented by General Formula 1 to the repeating unit represented by General Formula 2 (General Formula 1:General Formula 2), it can be confirmed that when the molar ratio is 80:20 to 100:0, it is possible to reduce the appropriate exposure dose of the resist film without affecting the pattern shape of the resist film.

[0099] In Table 1, comparing Examples 1, 2 and 8 from the viewpoint of the number of halogen atoms, it can be seen that when the number of halogen atoms is four, sufficient secondary electrons are generated and the appropriate exposure dose of the resist film is reduced.

[0100] In Table 1, by comparing Examples 1 to 4 from the viewpoint of the type of halogen atom, it can be confirmed that when the halogen atom is an iodine atom, sufficient secondary electrons are generated, resulting in a lower appropriate exposure dose of the resist film.

[0101] Comparing Comparative Example 1 with Examples 1 to 9 in terms of compound structure in Table 1, the polymer compounds for forming resist underlayer films produced by the methods of Examples 1 to 9 contain a repeating unit represented by General Formula 1 above, or additionally a repeating unit represented by General Formula 2 above. This allows the effect of maintaining the same roughness and size of the resist pattern film even with an exposure dose that is lower than the appropriate exposure dose for the resist film due to the influence of secondary electrons that increase the photon absorption rate of the resist underlayer film.

[0102] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

Claims

1. A polymer compound for forming a resist underlayer film, comprising a repeating unit represented by the following general formula 1: [General formula 1] In the general formula 1, R ０ is a hydrogen atom; or a linear or branched alkyl group having 1 to 4 carbon atoms, R １ , R ２ , R ３ , R ４ , and R ５ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a halogen atom, or a hydroxy group, The R １ , R ２ , R ３ , R ４ , and R ５ At least one of them is a halogen atom, and at least one of them is a hydroxy group.

2. The R １ , R ２ , R ３ , R ４ , and R ５ wherein four selected from the above contain halogen atoms; The polymer compound for forming a resist underlayer film according to claim 1 .

3. The halogen atom is a fluorine atom or an iodine atom. The polymer compound for forming a resist underlayer film according to claim 1 .

4. Further comprising a repeating unit derived from an unsaturated compound containing one or more crosslinking reactive functional groups at one end thereof; The polymer compound for forming a resist underlayer film according to claim 1 .

5. The crosslinking reactive functional group is a hydroxy group or a thiol group. The polymer compound for forming a resist underlayer film according to claim 4 .

6. The unsaturated compound is an acrylic compound. The polymer compound for forming a resist underlayer film according to claim 4 .

7. Further containing a repeating unit represented by the following general formula 2: The polymer compound for forming a resist underlayer film according to claim 1: [General formula 2] In the general formula 2, R ６ is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, A is a substituted or unsubstituted linear saturated hydrocarbon linking group having 2 to 12 carbon atoms; a substituted or unsubstituted linear unsaturated hydrocarbon linking group having 3 to 12 carbon atoms and containing one or more unsaturated bonds; or a substituted or unsubstituted ring linking group having 3 to 12 carbon atoms.

8. the molar ratio of the repeating unit represented by the general formula 1 to the repeating unit represented by the general formula 2 is 50:50 or more and 100:0 or less; The polymer compound for forming a resist underlayer film according to claim 7 .

9. In the general formula 1, the ratio of hydroxy groups to halogen atoms is 1:1 to 1:

4. The polymer compound for forming a resist underlayer film according to claim 1 .

10. The polymer compound for forming a resist underlayer film according to claim 1 , a solvent; A composition for forming a resist underlayer film.

11. the content of the polymer compound for forming a resist underlayer film is 0.02 to 1.00 wt % based on the total weight of the composition for forming a resist underlayer film; The composition for forming a resist underlayer film according to claim 10.

12. Further comprising at least one of a crosslinking agent and a thermal acid generator; The composition for forming a resist underlayer film according to claim 10.

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