Hardmask composition, hardmask layer, and method of forming patterns

Abstract

To provide a hardmask composition that can be effectively applied to a hardmask layer.SOLUTION: A hardmask composition comprises a polymer including a structural unit represented by Chemical Formula 1 and a solvent. The definitions of Chemical Formula 1 are as described in the specification.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hard mask composition, a hard mask layer containing a cured product of the hard mask composition, and a pattern forming method using the hard mask composition. [Background technology]

[0002] In recent years, the semiconductor industry has evolved from patterns of several hundred nanometers to ultrafine technology with patterns of several to several tens of nanometers. To realize such ultrafine technology, effective lithographic techniques are essential.

[0003] A typical lithographic technique involves forming a material layer on a semiconductor substrate, coating a photoresist layer thereon, exposing and developing the material layer to form a photoresist pattern, and then etching the material layer using the photoresist pattern as a mask.

[0004] In recent years, as the size of the pattern to be formed has decreased, it has become difficult to form a fine pattern with a good profile using only the typical lithographic techniques described above. Therefore, a supplementary layer called a hard mask layer is formed between the material layer to be etched and the photoresist layer to form the fine pattern. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Korean Patent Publication No. 10-2022-0092160 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a hard mask composition that can be effectively applied to a hard mask layer. [Means for solving the problem]

[0007] A hard mask composition according to one embodiment of the present invention includes a polymer having a structural unit represented by the following Formula 1, and a solvent:

[0008] [ka]

[0009] In the above chemical formula 1, A is a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 carbon atoms, or a ring assembly in which two or more substituted or unsubstituted aromatic rings having 6 to 30 carbon atoms are linked by a single bond or a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, B is represented by the following chemical formula 2: * is the connection point:

[0010] [ka]

[0011] In the above chemical formula 2, M is a substituted or unsubstituted hydrocarbon group having 1 to 40 carbon atoms; L is a single bond, -O-, -S-, -N-, a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, or a combination thereof; n is an integer of 3 or greater, * indicates a connection point.

[0012] In one embodiment, A can be a substituted or unsubstituted moiety selected from Group 1 below:

[0013] [ka]

[0014] In one embodiment, M may be a trivalent or tetravalent substituted or unsubstituted saturated or unsaturated aliphatic hydrocarbon group having 1 to 30 carbon atoms, a substituted or unsubstituted aromatic ring having 6 to 30 carbon atoms, or a ring assembly in which two or more substituted or unsubstituted aromatic rings having 6 to 20 carbon atoms are linked by a single bond or a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms.

[0015] In one embodiment, in the above Chemical Formula 2, M is a hydrocarbon group selected from Group 2 below, L is -O-, and n can be 3 or 4:

[0016] [ka]

[0017] In Group 2 above, * indicates a connection point.

[0018] In one embodiment, the polymer may further include a structural unit represented by the following formula 3:

[0019] [ka]

[0020] In the above chemical formula 3, C is a substituted or unsubstituted moiety selected from Group 3 below; D is a divalent organic group selected from Group 4 below, * is the connection point:

[0021] [ka]

[0022] In Group 4 above, * indicates a connection point.

[0023] In one embodiment, the structural unit represented by Chemical Formula 1 may be at least one selected from the group consisting of structural units represented by Chemical Formulas 1-1 to 1-5 below:

[0024] [ka]

[0025] In one embodiment, the weight average molecular weight of the polymer may be 1,000 g / mol to 200,000 g / mol.

[0026] In one embodiment, the polymer may be included in an amount of 0.1% by weight to 30% by weight based on the total weight of the hard mask composition.

[0027] In one embodiment, the solvent may be at least one selected from the group consisting of propylene glycol, propylene glycol diacetate, methoxypropanediol, diethylene glycol, diethylene glycol butyl ether, tri(ethylene glycol) monomethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, ethyl lactate, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, methylpyrrolidone (methylpyrrolidinone), acetylacetone, and ethyl 3-ethoxypropionate.

[0028] According to another embodiment of the present invention, there is provided a hard mask layer comprising a cured product of the hard mask composition described above.

[0029] According to yet another embodiment of the present invention, there is provided a patterning method including the steps of: providing a material layer on a substrate; applying the above-described hard mask composition on the material layer; heat-treating the hard mask composition to form a hard mask layer; forming a photoresist layer on the hard mask layer; exposing and developing the photoresist layer to form a photoresist pattern; selectively removing the hard mask layer using the photoresist pattern to expose portions of the material layer; and etching the exposed portions of the material layer.

[0030] In one embodiment, forming the hard mask layer includes heat treating the hard mask composition at 100°C to 1,000°C. [Effects of the Invention]

[0031] According to the present invention, a hard mask composition is provided that can be effectively applied to a hard mask layer. [Brief explanation of the drawings]

[0032] [Figure 1] FIG. 10 is a reference diagram showing a step in a hard mask layer as an example to explain a method for evaluating planarization characteristics. DETAILED DESCRIPTION OF THE INVENTION

[0033] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to exemplary embodiments thereof, so that those skilled in the art will be able to easily practice the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments set forth herein.

[0034] Unless otherwise defined in this specification, "substituted" means that a hydrogen atom in a compound is replaced with a halogen atom (F, Br, Cl, or I), a hydroxy group, an alkoxy group, a nitro group, a cyano group, an amino group, an azide group, an amidino group, a hydrazino group, a hydrazono group, a carbonyl group, a carbamoyl group, a thiol group, an ester group, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a vinyl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or a substituted or unsubstituted alkyl group having 2 to 20 carbon atoms. It means that the group is substituted with a substituent selected from an alkynyl group having 6 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl group having 7 to 30 carbon atoms, an arylaryl group having 9 to 30 carbon atoms, an alkoxy group having 1 to 30 carbon atoms, a heteroalkyl group having 1 to 20 carbon atoms, a heteroarylalkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, a cycloalkenyl group having 3 to 15 carbon atoms, a cycloalkynyl group having 6 to 15 carbon atoms, a heterocycloalkyl group having 3 to 30 carbon atoms, and combinations thereof.

[0035] Furthermore, two adjacent substituents in a substituted halogen atom (F, Br, Cl, or I), a hydroxy group, a nitro group, a cyano group, an amino group, an azide group, an amidino group, a hydrazino group, a hydrazono group, a carbonyl group, a carbamoyl group, a thiol group, an ester group, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl group having 7 to 30 carbon atoms, an alkoxy group having 1 to 30 carbon atoms, a heteroalkyl group having 1 to 20 carbon atoms, a heteroarylalkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, a cycloalkenyl group having 3 to 15 carbon atoms, a cycloalkynyl group having 6 to 15 carbon atoms, or a heterocyclic group having 2 to 30 carbon atoms can be fused to form a ring.

[0036] Unless otherwise defined in this specification, the term "aromatic hydrocarbon ring" refers to a group having one or more hydrocarbon aromatic moieties, and includes not only non-fused aromatic hydrocarbon rings and fused aromatic hydrocarbon rings, but also forms in which hydrocarbon aromatic moieties are linked by a single bond, forms of non-aromatic fused rings to which hydrocarbon aromatic moieties are directly or indirectly fused, or combinations thereof.

[0037] More specifically, the substituted or unsubstituted aromatic hydrocarbon ring is a substituted or unsubstituted phenyl group (phenylene group), a substituted or unsubstituted naphthyl group (naphthylene group), a substituted or unsubstituted anthracenyl group (anthracenylene group), a substituted or unsubstituted phenanthryl group (phenanthrylene group), a substituted or unsubstituted naphthacenyl group (naphthacenylene group), a substituted or unsubstituted pyrenyl group (pyrenylene group), a substituted or unsubstituted biphenyl group (biphenylene group), or a substituted or unsubstituted terphenyl group. (terphenylene group), a substituted or unsubstituted quaterphenyl group (quaterphenylene group), a substituted or unsubstituted chrysenyl group (chrysenylene group), a substituted or unsubstituted triphenylenyl group (triphenylenylene group), a substituted or unsubstituted perylenyl group (perylenylene group), a substituted or unsubstituted indenyl group (indenylene group), a substituted or unsubstituted fluorenyl group (fluorenylene group), a combination thereof, or a condensed form of a combination thereof, but is not limited to these.

[0038] Unless otherwise defined herein, "combination" means blending or copolymerization.

[0039] Unless otherwise defined herein, the term "polymer" can encompass both oligomers and polymers.

[0040] Unless otherwise defined in this specification, the "weight average molecular weight" is measured by dissolving a powder sample in tetrahydrofuran (THF) and then using a 1200 series gel permeation chromatography (GPC) manufactured by Agilent Technologies (using a Shodex LF-804 column and Shodex polystyrene as the standard sample).

[0041] The semiconductor industry continues to demand smaller chip sizes. To meet this demand, the linewidth of resists patterned using lithography must be on the order of tens of nanometers. This limits the height that resist patterns can withstand, and resists may not be sufficiently resistant to the etching process. To address this issue, an auxiliary layer known as a hard mask layer may be used between the material layer to be etched and the photoresist layer. This hard mask layer acts as an intermediate layer that transfers the fine pattern of the photoresist to the material layer through selective etching. Therefore, the hard mask layer must be heat-resistant and etch-resistant to withstand the etching process required for pattern transfer. Furthermore, when there are steps on the substrate being processed during multiple patterning processes, or when densely patterned and unpatterned areas coexist on the wafer, the hard mask layer that fills the patterns must have planarization properties that minimize the steps between the patterns.

[0042] Existing hard mask layers are formed by chemical vapor deposition or physical vapor deposition, but these methods require large equipment scales and high process costs, resulting in poor economic viability. Therefore, a technology for forming hard mask layers using a spin coating method has recently been developed. The spin coating method is easier to process than conventional methods, and the hard mask layers formed using this method may have better gap fill and planarization properties. Therefore, a hard mask composition that can be applied to the spin coating method is required. However, a problem with hard mask layers formed using the spin coating method is that they have slightly reduced etch resistance. Therefore, a hard mask composition that can be applied to the spin coating method and that produces hard mask layers formed using this method is required to have etch resistance equivalent to that of hard mask layers formed using the chemical vapor deposition or physical vapor deposition method.

[0043] Therefore, research has been conducted to maximize the carbon content of hard mask compositions in order to improve the etching resistance of hard mask layers. However, as the carbon content of the polymer contained in the hard mask composition increases, the solubility in solvents tends to decrease. Therefore, the carbon content of the polymer contained in the hard mask composition must be maximized to improve the etching resistance of the hard mask layer formed therefrom, while also ensuring that the polymer is highly soluble in solvents.

[0044] A hard mask composition according to one embodiment of the present invention includes a polymer having a structural unit represented by the following Formula 1, and a solvent:

[0045] [ka]

[0046] In the above chemical formula 1, A is a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 carbon atoms, or a ring assembly in which two or more substituted or unsubstituted aromatic rings having 6 to 30 carbon atoms are linked by a single bond or a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, B is represented by the following chemical formula 2: * is the connection point:

[0047] [ka]

[0048] In the above chemical formula 2, M is a substituted or unsubstituted hydrocarbon group having 1 to 40 carbon atoms; L is a single bond, -O-, -S-, -N-, a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, or a combination thereof; n is an integer of 3 or greater, * indicates a connection point.

[0049] As described above, the composition according to one embodiment includes a polymer structural unit that includes an aromatic ring or a ring assembly including two or more aromatic rings, thereby increasing the carbon content of the composition and ensuring the etching resistance of a hard mask layer formed from the composition.

[0050] Furthermore, the structural unit contains a linking group represented by Chemical Formula 2, thereby forming a branched structure in the polymer and thereby forming a crosslinked structure between the polymers. This allows the polymer to have a denser structure, and a hard mask layer formed from a composition containing the polymer can ensure excellent heat resistance. In addition, the linking group represented by Chemical Formula 2 imparts flexibility to the polymer, increasing the solubility of the polymer in a solvent and ensuring excellent gap-fill properties.

[0051] In the above formula 1, A can be a substituted or unsubstituted moiety selected from Group 1 below:

[0052] [ka]

[0053] In the above chemical formula 2, M may be a trivalent or tetravalent substituted or unsubstituted saturated or unsaturated aliphatic hydrocarbon group having 1 to 30 carbon atoms, a substituted or unsubstituted aromatic ring having 6 to 30 carbon atoms, or a ring assembly in which two or more substituted or unsubstituted aromatic rings having 6 to 20 carbon atoms are linked by a single bond or a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms. For example, M may be, but is not limited to, a trivalent or tetravalent substituted or unsubstituted saturated or unsaturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a ring assembly in which two or more substituted or unsubstituted aromatic rings having 6 to 20 carbon atoms are linked by a single bond or a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms.

[0054] For example, M in the above Chemical Formula 2 may be a hydrocarbon group selected from Group 2 below, but is not limited thereto.

[0055] [ka]

[0056] In Group 2 above, * indicates a connection point.

[0057] In the above chemical formula 2, L may be a single bond, -O-, -S-, -N-, a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms, or a combination thereof, for example, but not limited to, a single bond, -O-, a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms, or a combination thereof, for example, -O-. When L is -O-, -S-, or -N-, the solubility of the polymer in a solvent can be further increased.

[0058] In the above chemical formula 2, n is an integer of 3 or greater, and does not exceed the valence of M. When n is an integer of 3 or greater, the polymer containing the linking group represented by the above chemical formula 2 has a branched structure, which forms crosslinks between polymers and makes the structure of the polymer containing this more compact. For example, n can be an integer of 3 to 6, such as 3 or 4, but is not limited thereto.

[0059] In the above chemical formula 2, * is a linking point where A is linked to A in the same structural unit or A in a different structural unit.

[0060] In another embodiment, the polymer may further include a structural unit represented by the following formula 3:

[0061] [ka]

[0062] In the above chemical formula 3, C is a substituted or unsubstituted moiety selected from Group 3 below; D is a divalent organic group selected from Group 4 below, * is the connection point:

[0063] [ka]

[0064] In Group 4 above, * indicates a connection point.

[0065] When the polymer further includes a structural unit represented by Chemical Formula 3, the carbon content in the polymer can be increased, and the etching resistance of a hard mask layer formed from a composition including the polymer can be further improved.

[0066] For example, the structural unit represented by Chemical Formula 1 may be at least one selected from the group consisting of structural units represented by Chemical Formulas 1-1 to 1-5 below:

[0067] [ka]

[0068] The polymer may have a weight-average molecular weight of 1,000 g / mol to 200,000 g / mol. The polymer may have a weight-average molecular weight of, for example, 1,000 g / mol to 150,000 g / mol, for example, 1,000 g / mol to 100,000 g / mol, for example, 1,200 g / mol to 50,000 g / mol, for example, 1,200 g / mol to 10,000 g / mol, but is not limited thereto. By having a weight-average molecular weight within the above range, the carbon content and solubility in a solvent of a hard mask composition containing the polymer can be adjusted and optimized.

[0069] The polymer may be included in an amount of 0.1% by mass to 30% by mass based on the total mass of the hard mask composition. The amount of the polymer may be, but is not limited to, 0.2% by mass to 30% by mass, for example, 0.5% by mass to 30% by mass, for example, 1% by mass to 30% by mass, for example, 1.5% by mass to 25% by mass, or for example, 2% by mass to 20% by mass based on the total mass of the hard mask composition. By including the polymer in the above range, the thickness, surface roughness, and degree of planarization of the hard mask layer can be easily adjusted.

[0070] A hard mask composition according to one embodiment of the present invention includes a solvent. Examples of the solvent include, but are not limited to, at least one selected from the group consisting of propylene glycol, propylene glycol diacetate, methoxypropanediol, diethylene glycol, diethylene glycol butyl ether, tri(ethylene glycol) monomethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, ethyl lactate, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, methylpyrrolidone (methylpyrrolidinone), acetylacetone, and ethyl 3-ethoxypropionate. Two or more solvents may be mixed and used. The solvent is not particularly limited as long as it has sufficient solubility and / or dispersibility in the polymer.

[0071] The hard mask composition may further include additives such as a surfactant, a crosslinking agent, a thermal acid generator, and a plasticizer.

[0072] Examples of the surfactant that can be used include, but are not limited to, fluoroalkyl compounds, alkylbenzenesulfonates, alkylpyridinium salts, polyethylene glycols, and quaternary ammonium salts.

[0073] Examples of the crosslinking agent include melamine-based agents, substituted urea-based agents, and polymers thereof. A crosslinking agent having at least two crosslink-forming substituents is preferred, and compounds such as methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxymethylated benzoguanamine, methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, and butoxymethylated thiourea can be used.

[0074] Furthermore, a crosslinking agent having high heat resistance can be used as the crosslinking agent. As the crosslinking agent having high heat resistance, a compound containing a crosslink-forming substituent having an aromatic ring (e.g., a benzene ring or a naphthalene ring) in the molecule can be used.

[0075] Examples of the thermal acid generator that can be used include, but are not limited to, acidic compounds such as p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonate, salicylic acid, sulfosalicylic acid, citric acid, benzoic acid, hydroxybenzoic acid, and naphthalenecarboxylic acid, and / or 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, and other organic sulfonic acid alkyl esters.

[0076] According to another embodiment of the present invention, there is provided a hard mask layer comprising a cured product of the hard mask composition described above.

[0077] A method for forming a pattern using the above-described hard mask composition will now be described.

[0078] A patterning method according to one embodiment of the present invention includes the steps of providing a material layer on a substrate, applying a hard mask composition containing the above-described polymer and a solvent onto the material layer, heat-treating the hard mask composition to form a hard mask layer, forming a photoresist layer on the hard mask layer, exposing and developing the photoresist layer to form a photoresist pattern, selectively removing the hard mask layer using the photoresist pattern to expose a portion of the material layer, and etching the exposed portion of the material layer.

[0079] The substrate may be, for example, a silicon wafer, a glass substrate, or a polymer substrate. The material layer is a material on which a pattern is to be formed, and may be, for example, a metal layer such as aluminum or copper, a semiconductor layer such as silicon, or an insulating layer such as silicon oxide or silicon nitride. The material layer may be formed by, for example, chemical vapor deposition.

[0080] The hard mask composition may be prepared in the form of a solution and applied by spin coating, as described above. The thickness of the hard mask composition is not particularly limited, but may be, for example, 50 to 200,000 Å.

[0081] The step of heat-treating the hard mask composition may be performed, for example, at 100° C. to 1,000° C. for 10 seconds to 1 hour. For example, the step of heat-treating the hard mask composition may include multiple heat-treatment steps, for example, a first heat-treatment step and a second heat-treatment step.

[0082] In one embodiment, the step of heat-treating the hard mask composition may include a single heat-treatment step performed at 100°C to 1000°C for 10 seconds to 1 hour. For example, the heat-treatment step may be performed in an air or nitrogen atmosphere, or in an atmosphere having an oxygen concentration of 1% by weight or less.

[0083] In one embodiment, the step of heat-treating the hard mask composition may include a first heat-treatment step performed at, for example, 100°C to 1,000°C, for example, 100°C to 800°C, for example, 100°C to 500°C, for example, 150°C to 400°C, for 30 seconds to 1 hour, for example, 30 seconds to 30 minutes, for example, 30 seconds to 10 minutes, for example, 30 seconds to 5 minutes.

[0084] Furthermore, after the first heat treatment step, a second heat treatment step may be consecutively performed at, for example, 100°C to 1,000°C, for example, 300°C to 1,000°C, for example, 500°C to 1,000°C, for example, 500°C to 600°C, for 30 seconds to 1 hour, for example, 30 seconds to 30 minutes, for example, 30 seconds to 10 minutes, for example, 30 seconds to 5 minutes. For example, the first and second heat treatment steps may be performed in an air or nitrogen atmosphere, or in an atmosphere with an oxygen concentration of 1% by mass or less.

[0085] At least one of the heat-treating steps of the hard mask composition is performed at a high temperature of 200°C or higher, thereby exhibiting high etching resistance that can withstand etching gases and chemical solutions to which the hard mask composition is exposed in subsequent processes, including etching processes.

[0086] In one embodiment, forming the hard mask layer may include a UV / Vis cure step and / or a near IR cure step.

[0087] In one embodiment, the step of forming the hard mask layer may include at least one of the first heat treatment step, the second heat treatment step, the UV / Vis curing step, and the near IR curing step, or may include two or more of these steps consecutively.

[0088] In one embodiment, the method may further include forming a silicon-containing thin film layer on the hard mask layer, which may be formed of a material such as SiCN, SiOC, SiON, SiOCN, SiC, SiO, and / or SiN.

[0089] In one embodiment, before forming the photoresist layer, a bottom anti-reflective coating (BARC) may be further formed on the silicon-containing thin film layer or the hard mask layer.

[0090] In one embodiment, the step of exposing the photoresist layer may be performed using, for example, an ArF excimer laser, a KrF excimer laser, or extreme ultraviolet (EUV) light, etc. After the exposure, a heat treatment process may be further performed at, for example, 100°C to 700°C.

[0091] In one embodiment, the step of etching the exposed portions of the material layer can be performed by dry etching using an etching gas, such as N2 / O2, CHF3, CF4, Cl2, BCl3, and mixtures thereof.

[0092] The etched material layer may be formed in multiple patterns, which may be diverse, such as metal patterns, semiconductor patterns, insulating patterns, etc., and may be applied as various patterns within a semiconductor integrated circuit device, for example. [Example]

[0093] The above-described embodiments of the present invention will be described in more detail with reference to the following examples, which are provided for illustrative purposes only and are not intended to limit the scope of the present invention.

[0094] [Polymer synthesis] (Synthesis of Compounds 1c to 4c) (Synthesis Example 1) A flask was charged with 4-hydroxybenzaldehyde (40.3 g, 0.33 mol), 1,3-dibromo-2-(bromomethyl)-2-methylpropane (30.6 g, 0.1 mol), potassium carbonate (82.9 g, 0.6 mol), and 400 mL of anhydrous dimethylformamide (DMF), and the mixture was stirred at 100°C for 14 hours under a nitrogen stream.

[0095] After the reaction was completed, the reactant was cooled to room temperature and slowly added dropwise to 1,000 ml of cold water. The resulting solid was filtered and washed twice with water (500 ml) and with an aqueous methanol solution (water:MeOH = 3:1 (volume ratio), 200 ml). The remaining solvent was then removed under reduced pressure to obtain compound 1a represented by the following formula 1a.

[0096] [ka]

[0097] Compound 1a (43.2 g, 0.1 mol) was dissolved in 500 ml of a mixed solvent of dichloromethane and MeOH in a volume ratio of 1:1, and sodium borohydride (34 g, 0.9 mol) was slowly added over 20 minutes at room temperature, followed by stirring at room temperature for 5 hours.

[0098] After the reaction was completed, about half of the solvent was removed under reduced pressure, and the organic layer was extracted with ethyl acetate (600 ml), and the remaining solvent was removed under reduced pressure to obtain compound 1b represented by the following formula 1b.

[0099] [ka]

[0100] Compound 1b (21.9 g, 0.05 mol) was dissolved in 150 ml of anhydrous dimethylformamide (DMF), and then sodium hydride (12 g, 0.5 mol) was slowly added while blowing nitrogen, followed by stirring at room temperature for 30 minutes. Iodomethane (71 g, 0.5 mol) was slowly added dropwise to the reaction mixture, followed by stirring at room temperature for 3 hours.

[0101] After the reaction was completed, the organic layer was extracted with ethyl acetate (500 ml), and the remaining solvent was removed under reduced pressure, followed by column chromatography to obtain compound 1c represented by the following formula 1c.

[0102] [ka]

[0103] (Synthesis Example 2) Compound 2c represented by the following chemical formula 2c was obtained in the same manner as in Synthesis example 1 above, except that 4-fluorobenzaldehyde was used instead of 4-hydroxybenzaldehyde and 2,4-bis[2-(4-hydroxyphenyl)-2-propanyl]phenol was used instead of 1,3-dibromo-2-(bromomethyl)-2-methylpropane.

[0104] [ka]

[0105] (Synthesis Example 3) Compound 3c represented by the following chemical formula 3c was obtained in the same manner as in Synthesis example 2 above, except that 4,4'-(1-(4-(2-(4-hydroxyphenyl)propan-2-yl)phenyl)ethane-1,1-diyl)diphenol was used instead of 2,4-bis[2-(4-hydroxyphenyl)-2-propanyl]phenol.

[0106] [ka]

[0107] (Synthesis Example 4) Compound 4c represented by the following chemical formula 4c was obtained in the same manner as in Synthesis Example 2 above, except that 1,1,2,2-Tetrakis(p-hydroxyphenyl)ethane was used instead of 2,4-bis[2-(4-hydroxyphenyl)-2-propanyl]phenol.

[0108] [ka]

[0109] (Synthesis of Polymers 1 to 5, Comparative Polymers 1 and 2) (Polymerization Example 1) 9,9-Bis(6-hydroxy-2-naphthyl)fluorene (22.5 g, 0.05 mol), the above compound 1c (15.8 g, 0.033 mol), diethyl sulfate (0.15 g), and propylene glycol monomethyl ether acetate (PGMEA, 150 g) were sequentially placed in a flask, and the mixture was stirred at 90°C for 6 hours to polymerize.

[0110] After the reaction was complete, the reaction mixture was added to 50 g of distilled water and 200 g of methanol, stirred vigorously, and then allowed to stand. The supernatant was then removed, and the precipitate was dissolved in 60 g of propylene glycol monomethyl ether acetate. The resulting solution was then stirred vigorously with 200 g of methanol and allowed to stand. This purification process was repeated five times, and the purified polymer was dissolved in 100 g of propylene glycol monomethyl ether acetate (PGMEA). The residual solvent was removed under reduced pressure to obtain Polymer 1, which has a weight-average molecular weight of 2,500 g / mol and is composed of structural units represented by the following chemical formula 1-1:

[0111] [ka]

[0112] (Polymerization Example 2) Polymer 2 having a weight average molecular weight of 2,500 g / mol and composed of structural units represented by the following chemical formula 1-2 was obtained in the same manner as in Polymerization Example 1 above, except that compound 2c was used instead of compound 1c.

[0113] [ka]

[0114] (Polymerization Example 3) Polymer 3 having a weight average molecular weight of 2,500 g / mol and composed of structural units represented by the following chemical formula 1-3 was obtained in the same manner as in Polymerization Example 1, except that 1-hydroxypyrene was used instead of 9,9-bis(6-hydroxy-2-naphthyl)fluorene and compound 3c was used instead of compound 1c.

[0115] [ka]

[0116] (Polymerization Example 4) Polymer 4 having a weight average molecular weight of 2,500 g / mol and composed of structural units represented by the following chemical formula 1-4 was obtained in the same manner as in Polymerization Example 3, except that compound 4c was used instead of compound 1c.

[0117] [ka]

[0118] (Polymerization Example 5) 9,9-bis(6-hydroxy-2-naphthyl)fluorene (22.5 g, 0.05 mol), compound 1c (9.6 g, 0.02 mol), diethyl sulfate (0.15 g), and propylene glycol monomethyl ether acetate (PGMEA, 150 g) were sequentially placed in a flask and stirred at 90 °C for 2 hours to polymerize. 1,4-bis(methoxymethyl)benzene (3.3 g, 0.02 mol) was then added and stirred for 4 hours.

[0119] After the reaction was complete, the reaction mixture was added to 50 g of distilled water and 200 g of methanol, stirred vigorously, and then allowed to stand. The supernatant was then removed, and the precipitate was dissolved in 60 g of propylene glycol monomethyl ether acetate. Then, 200 g of methanol was added, stirred vigorously, and allowed to stand. The purification process was repeated twice more, and the purified polymer was dissolved in 100 g of propylene glycol monomethyl ether acetate (PGMEA). The residual solvent was removed under reduced pressure to obtain Polymer 5, which has a weight-average molecular weight of 2,500 g / mol and is composed of structural units represented by the following chemical formula 1-5:

[0120] [ka]

[0121] (Comparative Polymerization Example 1) 9,9-bis(6-hydroxy-2-naphthyl)fluorene (22.5 g, 0.05 mol) and paraformaldehyde (1.5 g, 0.05 mol) were placed in a flask, and 0.57 g (0.003 mol) of p-toluenesulfonic acid monohydrate was dissolved in 163 g of propylene glycol monomethyl ether acetate (PGMEA). The mixture was then stirred at 90°C for 15 hours to polymerize.

[0122] After the reaction was complete, the reaction mixture was added to 40 g of distilled water and 300 g of methanol, stirred vigorously, and then allowed to stand. The supernatant was then removed, and the precipitate was dissolved in 80 g of propylene glycol monomethyl ether acetate. The resulting solution was then stirred vigorously with 300 g of methanol and allowed to stand. This purification process was repeated five times, and the purified polymer was dissolved in 100 g of propylene glycol monomethyl ether acetate (PGMEA). The remaining methanol and distilled water were then removed under reduced pressure to obtain Comparative Polymer 1, which has a weight-average molecular weight of 2,500 g / mol and is composed of structural units represented by the following chemical formula X:

[0123] [ka]

[0124] (Comparative Polymerization Example 2) Comparative Polymer 2 having a weight average molecular weight of 2,500 g / mol and comprising a structural unit represented by the following chemical formula Y was obtained in the same manner as in Comparative Polymerization Example 1, except that 1-hydroxypyrene was used instead of 9,9-bis(6-hydroxy-2-naphthyl)fluorene and 1,4-bis(methoxymethyl)benzene was used instead of paraformaldehyde.

[0125] [ka]

[0126] [Preparation of hard mask composition] Examples 1-1 to 5-1 and Comparative Examples 1-1 to 2-1 The polymers obtained in Polymerization Examples 1 to 5 and Comparative Polymerization Examples 1 and 2 were each uniformly dissolved in a solvent in which propylene glycol monomethyl ether acetate and cyclohexanone were mixed in a volume ratio of 1:1 to prepare hard mask compositions with a solid content of approximately 15% by mass.

[0127] Examples 1-2 to 5-2 and Comparative Examples 1-2 to 2-2 The polymers obtained in Polymerization Examples 1 to 5 and Comparative Polymerization Examples 1 and 2 were each uniformly dissolved in a solvent in which propylene glycol monomethyl ether acetate and cyclohexanone were mixed in a volume ratio of 1:1 to prepare hard mask compositions having a solid content of 5 to 10 mass %.

[0128] [Evaluation 1: Heat resistance evaluation] The hard mask compositions according to Examples 1-1 to 5-1 and Comparative Examples 1-1 to 2-1 were applied onto silicon wafers and then heat-treated on a hot plate at 150°C for 2 minutes to form hard mask films. The heat resistance was evaluated using a thermogravimetric analyzer (TGA) under air heating conditions. The results are shown in Table 1 below. In Table 1 below, T 95 (°C) is the temperature at which the residual weight of the hard mask film is 95% of the initial weight, and T 90 (°C) is the temperature at which the residual weight of the hard mask film is 90% of the initial weight.

[0129] [Table 1]

[0130] Referring to Table 1 above, the T of the hard mask films formed from the compositions according to Examples 1-1 to 5-1 95 and T 90 It can be seen that the heat resistance of the resulting hard mask layers is improved when using the hard mask compositions of Examples 1-1 to 5-1 compared to the hard mask films formed using the compositions of Comparative Examples 1-1 to 2-1.

[0131] [Evaluation 2: Planarization and Gap Fill Characteristics Evaluation] The hard mask compositions according to Examples 1-2 to 5-2 and Comparative Examples 1-2 to 2-2 were applied to patterned wafers (aspect ratio = 1:2) and heat-treated on a hot plate at 400°C for 2 minutes to form thin films with thicknesses of 2,000 Å to 2,100 Å. The gap-fill properties and planarization performance were then evaluated using a scanning electron microscope (SEM).

[0132] The gap-fill characteristics were evaluated by observing the presence or absence of voids in the cross section of the thin film pattern using a scanning electron microscope (SEM). The planarization characteristics were evaluated from the result of the following calculation formula 1 regarding the degree of planarization (%). Referring to Figure 1, h1 in the following calculation formula 1 is the average value of the thin film thickness measured at three arbitrary points on the substrate where no pattern is formed, and h2 is the average value of the thin film thickness measured at three arbitrary points on the substrate where a pattern is formed. The thin film thickness was measured using a thin film thickness measuring device manufactured by K-MAC. The higher the degree of planarization, the better the planarization characteristics. The results of the gap-fill and planarization characteristics evaluation are shown in Table 2 below. [Formula 1] Flatness degree (%)=(h2 / h1)×100(%)

[0133] [Table 2]

[0134] Referring to Table 2, it can be seen that the hard mask layers formed from the hard mask compositions of Examples 1-2 to 5-2 have better planarization and gap-fill properties than the hard mask layers formed from the hard mask compositions of Comparative Examples 1-2 to 2-2.

[0135] 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 hard mask composition comprising a polymer having a structural unit represented by the following chemical formula 1, and a solvent: 【Chemical 1】 In the above Chemical Formula 1, A is a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 carbon atoms, or a ring assembly in which two or more substituted or unsubstituted aromatic rings having 6 to 30 carbon atoms are connected by a single bond or a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms; B is represented by the following chemical formula 2: * is the connection point: 【Chemistry 2】 In the above Chemical Formula 2, M is a substituted or unsubstituted hydrocarbon group having 1 to 40 carbon atoms; L represents a single bond, —O—, —S—, —N—, a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, or a combination thereof; n is an integer of 3 or more, * indicates a connection point.

2. 2. The hard mask composition of claim 1, wherein A is a substituted or unsubstituted moiety selected from Group 1: 【Chemistry 3】

3. 2. The hard mask composition according to claim 1, wherein M is a trivalent or tetravalent substituted or unsubstituted, saturated or unsaturated aliphatic hydrocarbon group having 1 to 30 carbon atoms, a substituted or unsubstituted aromatic ring having 6 to 30 carbon atoms, or a ring assembly in which two or more substituted or unsubstituted aromatic rings having 6 to 20 carbon atoms are connected by a single bond or a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms.

4. 2. The hard mask composition of claim 1, wherein, in Formula 2, M is a hydrocarbon group selected from Group 2 below, L is —O—, and n is 3 or 4: 【Chemistry 4】 In Group 2, * indicates a connection point.

5. 10. The hard mask composition of claim 1, wherein the polymer further comprises a structural unit represented by the following formula 3: 【Chemistry 5】 In the above Chemical Formula 3, C is a substituted or unsubstituted moiety selected from Group 3 below: D is a divalent organic group selected from Group 4 below, * is the connection point: 【Chemistry 6】 In Group 4, * indicates a connection point.

6. 2. The hard mask composition of claim 1, wherein the structural unit represented by Chemical Formula 1 is at least one selected from the group consisting of structural units represented by the following Chemical Formulas 1-1 to 1-5: 【Chemistry 7】

7. 2. The hard mask composition of claim 1, wherein the weight average molecular weight of the polymer is 1,000 g / mol to 200,000 g / mol.

8. The hard mask composition of claim 1 , wherein the polymer is contained in an amount of 0.1% by weight to 30% by weight based on the total weight of the hard mask composition.

9. 2. The hard mask composition of claim 1, wherein the solvent is at least one selected from the group consisting of propylene glycol, propylene glycol diacetate, methoxypropanediol, diethylene glycol, diethylene glycol butyl ether, tri(ethylene glycol) monomethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, ethyl lactate, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, methylpyrrolidone, acetylacetone, and ethyl 3-ethoxypropionate.

10. A hard mask layer comprising a cured product of the hard mask composition according to any one of claims 1 to 9.

11. providing a layer of material on a substrate; applying a hard mask composition according to any one of claims 1 to 9 onto the material layer; heat-treating the hard mask composition to form a hard mask layer; forming a photoresist layer on the hard mask layer; exposing and developing the photoresist layer to form a photoresist pattern; selectively removing the hard mask layer using the photoresist pattern to expose a portion of the material layer; etching the exposed portions of the layer of material; A pattern forming method comprising:

12. 12. The pattern formation method of claim 11, wherein the forming of the hard mask layer comprises heat-treating the hard mask composition at a temperature of 100 to 1,000°C.

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