Resist underlayer compositions and methods of forming patterns using the compositions

Abstract

To provide a resist underlayer composition in which sensitivity is improved and patterning performance and energy efficiency are improved even in a fine patterning process.SOLUTION: A resist underlayer composition comprising a polymer including a structural unit represented by Chemical Formula 1, and a solvent. [Chemical Formula 1]SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a composition for a resist underlayer film and a pattern forming method using the same. [Background technology]

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

[0003] Lithography is a processing method in which a photoresist film is applied to a semiconductor substrate such as a silicon wafer to form a thin film, which is then irradiated with ultraviolet light such as i-line light through a mask pattern on which a device pattern is drawn, and then developed.The resulting photoresist pattern is used as a protective film to etch the substrate, thereby forming a fine pattern on the substrate surface that corresponds to the photoresist pattern.

[0004] As semiconductor patterns become finer, thinner photoresist layers are required, and so are thinner resist underlayers. A resist underlayer must be thin enough to maintain the photoresist pattern, have good adhesion to the photoresist, and be formed to a uniform thickness. Additionally, a resist underlayer must have a high refractive index and low absorption coefficient for the light used in photolithography, and an etching rate faster than that of the photoresist layer. Summary of the Invention [Problem to be solved by the invention]

[0005] The composition for a resist underlayer film according to one embodiment improves sensitivity to an exposure light source even in a fine patterning process, thereby improving patterning performance and energy efficiency, and providing a resist underlayer film on which a pattern is uniformly formed.

[0006] Another embodiment provides a pattern forming method using the above-mentioned resist underlayer film composition. [Means for solving the problem]

[0007] A composition for a resist underlayer film according to one embodiment includes a polymer including a structural unit represented by the following chemical formula 1, and a solvent.

[0008] [Chemical formula 1] [ka]

[0009] In chemical formula 1, R 1 ~R 3 are each independently hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group; L 1 represents a single bond, a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkenylene group, a substituted or unsubstituted C2-C10 alkynylene group, a substituted or unsubstituted C1-C10 heteroalkylene group, a substituted or unsubstituted C2-C10 heteroalkenylene group, or a combination thereof; X 1 represents a single bond, -O-, -C(=O)-, -(CO)O-, -O(CO)O-, -NR a -(where R a is hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group, or a combination thereof; Y 1 is *-(CH2)n-(CHI)m-CR x R y R z (where n is an integer from 0 to 5, m is 0 or 1, and R x ~R zare each independently a hydrogen, deuterium, or halogen atom; a substituted or unsubstituted C3 to C20 cycloalkyl group, two or more fused rings of a substituted or unsubstituted C3 to C10 cycloalkyl group, a substituted or unsubstituted C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a substituted or unsubstituted C2 to C20 heteroaryl group; * indicates a connection point.

[0010] L in Chemical Formula 1 1 is a substituted or unsubstituted C1-C10 alkylene group, and X 1 may be —(CO)O—.

[0011] The polymer may contain a structural unit represented by the following chemical formula 1-1.

[0012] [Chemical formula 1-1] [ka]

[0013] In chemical formula 1-1, R 4 is hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group; Y 2 is a substituted or unsubstituted methyl group, -CHICH3, a substituted or unsubstituted C3 to C20 cycloalkyl group, two or more fused rings of a substituted or unsubstituted C3 to C10 cycloalkyl group, or a substituted or unsubstituted C6 to C10 aryl group; * indicates a connection point.

[0014] The polymer may further include a structural unit represented by the following Chemical Formula 2:

[0015] [Chemical formula 2] [ka]

[0016] In chemical formula 2, R 5 ~R 7 are each independently hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group; X 2 and X 3 each independently represents a single bond, -O-, -S-, -S(=O)-, -S(=O)2-, -C(=O)-, -(CO)O-, -O(CO)O-, or -NR b -(where R b is hydrogen, deuterium, or a C1-C10 alkyl group, or a combination thereof; L 2 represents a single bond, a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C1-C10 heteroalkylene group, a substituted or unsubstituted C3-C20 cycloalkylene group, a substituted or unsubstituted C2-C20 heterocycloalkylene group, a substituted or unsubstituted C6-C20 arylene group, a substituted or unsubstituted C2-C20 heteroarylene group, or a combination thereof; Y 3 is hydrogen, deuterium, a hydroxy group, a nitro group, a cyano group, an amine group, -COOH, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C2-C10 alkenyl group, a substituted or unsubstituted C2-C10 alkynyl group, a substituted or unsubstituted C1-C10 heteroalkyl group, a substituted or unsubstituted C2-C10 heteroalkenyl group, a substituted or unsubstituted C2-C10 heteroalkynyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted C2-C20 heterocycloalkyl group, a substituted or unsubstituted C6-C20 aryl group, or a substituted or unsubstituted C2-C20 heteroaryl group; * indicates a connection point.

[0017] X in Chemical Formula 2 2 is -(CO)O-, and X 3 is a single bond, and Y 3may be a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, or a substituted or unsubstituted C6 to C20 aryl group.

[0018] The polymer may contain one or more structural units represented by the following chemical formulas 1-2 to 1-5.

[0019] [Chemical formula 1-2] [ka]

[0020] [Chemical formula 1-3] [ka]

[0021] [Chemical formula 1-4] [ka]

[0022] [Chemical formula 1-5] [ka]

[0023] The structural unit represented by Chemical Formula 1 may be 20% by weight to 80% by weight based on the total weight of the polymer.

[0024] The weight average molecular weight of the polymer may be from 1,000 g / mol to 300,000 g / mol.

[0025] The polymer may be contained in an amount of 0.1% by weight to 50% by weight based on the total weight of the composition for a resist underlayer film.

[0026] The composition may further include one or more polymers selected from acrylic resins, epoxy resins, novolac resins, glycoluril resins, and melamine resins.

[0027] The composition can further include an additive that is a surfactant, a thermal acid generator, a photoacid generator, a plasticizer, or a combination thereof.

[0028] According to another embodiment, there is provided a pattern forming method including the steps of forming a film to be etched on a substrate, applying a resist underlayer film composition according to an embodiment to the film to be etched to form a resist underlayer film, forming a photoresist pattern on the resist underlayer film, and sequentially etching the resist underlayer film and the film to be etched using the photoresist pattern as an etching mask. [Effects of the Invention]

[0029] The composition for a resist underlayer film according to one embodiment has excellent storage stability, and can provide a resist underlayer film that has improved sensitivity to an exposure light source even in a fine patterning process, thereby improving patterning performance and energy efficiency, and forming a uniform pattern. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a cross-sectional view illustrating a pattern forming method using a resist underlayer film composition according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0031] 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 can easily understand the present invention. However, the present invention may be embodied in many different forms and is not limited to the exemplary embodiments set forth herein.

[0032] In the drawings, the thickness of multiple layers and regions is exaggerated to clearly show them, and similar parts are designated by the same reference numerals throughout the specification. When a part such as a layer, film, region, or plate is said to be "on" another part, this includes not only the case where it is "directly on" the other part, but also the case where there is another part between them. Conversely, when a part is said to be "directly on" the other part, it means that there is no other part between them.

[0033] Hereinafter, unless otherwise defined in this specification, the term "substituted" means that a hydrogen atom in a compound is substituted with a substituent selected from deuterium, a 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, phosphoric acid or a salt thereof, a C1-C30 alkyl group, a C2-C30 alkenyl group, a C2-C30 alkynyl group, a C6-C30 aryl group, a C7-C30 arylalkyl group, a C1-C30 alkoxy group, a C1-C20 heteroalkyl group, a C3-C20 heteroarylalkyl group, a C3-C30 cycloalkyl group, a C3-C15 cycloalkenyl group, a C6-C15 cycloalkynyl group, a C2-C30 heterocyclic group, and combinations thereof.

[0034] Furthermore, two adjacent substituents among a substituted halogen atom (F, Br, Cl, or I), a hydroxy group, a nitro group, a cyano group, an amino group, an azido 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 C1-C30 alkyl group, a C2-C30 alkenyl group, a C2-C30 alkynyl group, a C6-C30 aryl group, a C7-C30 arylalkyl group, a C1-C30 alkoxy group, a C1-C20 heteroalkyl group, a C3-C20 heteroarylalkyl group, a C3-C30 cycloalkyl group, a C3-C15 cycloalkenyl group, a C6-C15 cycloalkynyl group, or a C2-C30 heterocyclic group may be fused to form a ring.

[0035] As used herein, the term "heterocyclic group" encompasses heteroaryl groups and, in addition, refers to a ring compound such as an aryl group, a cycloalkyl group, a fused ring thereof, or a combination thereof that contains at least one heteroatom selected from N, O, S, P, and Si in place of carbon (C) in the ring compound. When the heterocyclic group is a fused ring, the entire heterocyclic group or each ring may contain one or more heteroatoms.

[0036] More specifically, the substituted or unsubstituted aryl group and / or the substituted or unsubstituted heterocyclic group may be a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted phenanthryl group, a substituted or unsubstituted naphthacenyl group, a substituted or unsubstituted pyrenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, a substituted or unsubstituted quaterphenyl group, a substituted or unsubstituted chrysenyl group, a substituted or unsubstituted triphenylenyl group, a substituted or unsubstituted phenyl ... A substituted or unsubstituted perylenyl group, a substituted or unsubstituted indenyl group, a substituted or unsubstituted furanyl group, a substituted or unsubstituted thiophenyl group, a substituted or unsubstituted pyrrolyl group, a substituted or unsubstituted pyrazolyl group, a substituted or unsubstituted imidazolyl group, a substituted or unsubstituted triazolyl group, a substituted or unsubstituted oxazolyl group, a substituted or unsubstituted thiazolyl group, a substituted or unsubstituted oxadiazolyl group, a substituted or unsubstituted thiadiazolyl group, a substituted or unsubstituted pyridinyl group, a substituted or unsubstituted pyrimidinyl ... A radinyl group, a substituted or unsubstituted triazinyl group, a substituted or unsubstituted benzofuranyl group, a substituted or unsubstituted benzothiophenyl group, a substituted or unsubstituted benzimidazolyl group, a substituted or unsubstituted indolyl group, a substituted or unsubstituted quinolinyl group, a substituted or unsubstituted isoquinolinyl group, a substituted or unsubstituted quinazolinyl group, a substituted or unsubstituted quinoxalinyl group, a substituted or unsubstituted naphthyridinyl group, a substituted or unsubstituted benzoxazinyl group, a substituted or unsubstituted benzthiazinyl group, a substituted or unsubstituted acridinyl group, The alkyl group may be, but is not limited to, a substituted or unsubstituted phenyl group, a substituted or unsubstituted phenazinyl group, a substituted or unsubstituted phenothiazinyl group, a substituted or unsubstituted phenoxazinyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted carbazolyl group, a pyridoindolyl group, a benzopyridoxazinyl group, a benzopyridothiazinyl group, a 9,9-dimethyl-9,10-dihydroacridinyl group, a combination thereof, or a fused form of a combination thereof.

[0037] Unless otherwise specified herein, "combination" means blending or copolymerization.

[0038] In addition, in this specification, the term "polymer" can include both oligomers and polymers.

[0039] Unless otherwise specified in this specification, the "weight average molecular weight" is measured by dissolving a powder sample in tetrahydrofuran (THF) and then using Agilent Technologies' 1200 series gel permeation chromatography (GPC) (using a Shodex LF-804 column and Shodex polystyrene as the standard sample).

[0040] Additionally, unless otherwise defined herein, "*" indicates a structural unit of a polymer or a linking point of a moiety of a polymer.

[0041] The semiconductor industry is constantly demanding smaller chip sizes. To meet this demand, resist linewidths patterned using lithography must be reduced to the order of several tens of nanometers. This pattern must then be used to form patterns in the underlying material through an etching process of the underlying substrate. However, as the resist pattern size decreases, the resist height (aspect ratio) that can withstand the linewidth becomes limited, which can result in the resist not being able to withstand the etching step sufficiently. Therefore, resist underlayers have been used to compensate for this when using thin resist materials, when the substrate to be etched is thick, or when deep patterns are required.

[0042] As the thickness of the resist decreases, the resist underlayer film must also become thinner, and even a thin resist underlayer film must be able to maintain the photoresist pattern. Therefore, the resist underlayer film must have excellent adhesion to the photoresist. Furthermore, when forming a thin resist underlayer film, the coating uniformity of the resist underlayer film composition and the flatness of the resist underlayer film produced using the same must be improved, and the sensitivity to the exposure light source must be improved to improve pattern formability and energy efficiency.

[0043] A composition for a resist underlayer film according to one embodiment includes a polymer including a structural unit represented by the following chemical formula 1, and a solvent.

[0044] [Chemical formula 1] [ka]

[0045] In chemical formula 1, R 1 ~R 3 are each independently hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group; L 1 represents a single bond, a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkenylene group, a substituted or unsubstituted C2-C10 alkynylene group, a substituted or unsubstituted C1-C10 heteroalkylene group, a substituted or unsubstituted C2-C10 heteroalkenylene group, or a combination thereof; X 1 represents a single bond, -O-, -C(=O)-, -(CO)O-, -O(CO)O-, -NR a -(where R a is hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group, or a combination thereof; Y 1 is *-(CH2)n-(CHI)m-CR x R y R z(where n is an integer from 0 to 5, m is 0 or 1, and R x ~R z are each independently a hydrogen, deuterium, or halogen atom; a substituted or unsubstituted C3 to C20 cycloalkyl group, two or more fused rings of a substituted or unsubstituted C3 to C10 cycloalkyl group, a substituted or unsubstituted C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a substituted or unsubstituted C2 to C20 heteroaryl group; * indicates a connection point.

[0046] In one embodiment of the resist underlayer film composition, the polymer contains iodine, and therefore the composition has a high absorption rate of the exposure light source during exposure, thereby inducing the generation of secondary electrons in the photoresist on the upper part of the resist underlayer film and improving the sensitivity of the photoresist.

[0047] Specifically, the structural unit represented by chemical formula 1 contained in the polymer has a terminal functional group Y 1 The carbon atom bonded to the iodine is substituted with the iodine, thereby maximizing the absorption of light from the resist underlayer film composition and maximizing the sensitivity of the photoresist.

[0048] According to one embodiment, R 1 ~R 3 are each independently hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group, such as, but not limited to, hydrogen, a methyl group, or an ethyl group.

[0049] According to one embodiment, L 1is a single bond, a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkenylene group, a substituted or unsubstituted C2-C10 alkynylene group, a substituted or unsubstituted C1-C10 heteroalkylene group, or a combination thereof, such as a single bond, a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkenylene group, or a combination thereof, such as a single bond or a substituted or unsubstituted C1-C5 alkylene group, such as a C1-C5 alkylene group substituted with a hydroxy group, such as a propylene group substituted with a hydroxy group, but is not limited to these.

[0050] According to one embodiment, X 1 is a single bond, —O—, —C(═O)—, —(CO)O—, —O(CO)O—, —NH—, —N(CH)—, or a combination thereof, such as —(CO)O— or —NH—, such as, but not limited to, —(CO)O—.

[0051] According to one embodiment, Y 1 is *-(CH2)n-(CHI)m-CR x R y R z (where n is an integer from 0 to 5, m is 0 or 1, and R x ~R z are each independently a hydrogen, deuterium, or halogen atom.), a substituted or unsubstituted C3-C10 cycloalkyl group, two or more fused rings of a substituted or unsubstituted C3-C10 cycloalkyl group, a substituted or unsubstituted C2-C10 heterocycloalkyl group, a substituted or unsubstituted C6-C14 aryl group, or a substituted or unsubstituted C2-C20 heteroaryl group, such as, but not limited to, -(CH2)n-(CHI)m-CH3 (where n is an integer of 0 to 2, and m is 0 or 1), two or more fused rings of a substituted or unsubstituted C3-C10 cycloalkyl group, or a substituted or unsubstituted C6-C10 aryl group.

[0052] According to one embodiment, Chemical Formula 1 may include a structural unit represented by the following Chemical Formula 1-1.

[0053] [Chemical formula 1-1] [ka]

[0054] In chemical formula 1-1, R 4 is hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group, and Y 2 is a substituted or unsubstituted methyl group, -CHICH3, a substituted or unsubstituted C3 to C20 cycloalkyl group, two or more fused rings of a substituted or unsubstituted C3 to C10 cycloalkyl group, or a substituted or unsubstituted C6 to C10 aryl group, and * is the point of attachment.

[0055] According to one embodiment, Y 2 is, but is not limited to, a substituted or unsubstituted methyl group, -CHICH3, a substituted or unsubstituted C3-C10 cycloalkyl group, two or more fused rings of a substituted or unsubstituted C3-C10 cycloalkyl group, or a substituted or unsubstituted C6-C10 aryl group.

[0056] As an example, Y 2 The two or more fused rings of the substituted or unsubstituted C3-C10 cycloalkyl group may be formed by fusing two, three, or four substituted or unsubstituted C3-C10 cycloalkyl groups, for example, but not limited to, a fused ring formed by two cyclohexanes sharing two or three carbon atoms with different cyclohexanes, a fused ring formed by three cyclohexanes each sharing a carbon atom with a different cyclohexane, or a fused ring formed by four cyclohexanes each sharing a carbon atom with a different cyclohexane. For example, one or more hydrogen atoms in the fused ring may be substituted with another group, for example, but not limited to, iodine.

[0057] For example, the polymer may contain one or more structural units represented by the following formulas 1-2 to 1-5.

[0058] [Chemical formula 1-2] [ka]

[0059] [Chemical formula 1-3] [ka]

[0060] [Chemical formula 1-4] [ka]

[0061] [Chemical formula 1-5] [ka]

[0062] The polymer contained in the composition for a resist underlayer film according to another embodiment may further contain a structural unit represented by the following Chemical Formula 2:

[0063] [Chemical formula 2] [ka]

[0064] In chemical formula 2, R 5 ~R 7 are each independently hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group; X 2 and X 3 each independently represents a single bond, -O-, -S-, -S(=O)-, -S(=O)2-, -C(=O)-, -(CO)O-, -O(CO)O-, or -NR b -(where R bis hydrogen, deuterium, or a C1-C10 alkyl group, or a combination thereof; L 2 represents a single bond, a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C1-C10 heteroalkylene group, a substituted or unsubstituted C3-C20 cycloalkylene group, a substituted or unsubstituted C2-C20 heterocycloalkylene group, a substituted or unsubstituted C6-C20 arylene group, a substituted or unsubstituted C2-C20 heteroarylene group, or a combination thereof; Y 3 is hydrogen, deuterium, a hydroxy group, a nitro group, a cyano group, an amine group, -COOH, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C2-C10 alkenyl group, a substituted or unsubstituted C2-C10 alkynyl group, a substituted or unsubstituted C1-C10 heteroalkyl group, a substituted or unsubstituted C2-C10 heteroalkenyl group, a substituted or unsubstituted C2-C10 heteroalkynyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted C2-C20 heterocycloalkyl group, a substituted or unsubstituted C6-C20 aryl group, or a substituted or unsubstituted C2-C20 heteroaryl group; * indicates a connection point.

[0065] According to one embodiment, R 5 ~R 7 are each independently hydrogen, deuterium, or a substituted or unsubstituted C1 to C5 alkyl group, for example, but not limited to, hydrogen or a methyl group.

[0066] According to one embodiment, X 2 and X 3 are each independently a single bond, -O-, -S-, -S(=O)-, -S(=O)2-, -C(=O)-, -(CO)O-, -O(CO)O-, -NH-, or a combination thereof, for example, a single bond, -O-, -C(=O)-, -(CO)O-, -O(CO)O-, -NH-, or a combination thereof, for example, but not limited to, a single bond or -(CO)O-.

[0067] According to one embodiment, L 2 is a single bond, a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C1-C10 heteroalkylene group, or a combination thereof, for example, a single bond or a substituted or unsubstituted C1-C10 alkylene group, for example, a single bond or a substituted or unsubstituted C1-C5 alkylene group, but is not limited to these.

[0068] According to one embodiment, Y 3 is hydrogen, deuterium, a hydroxy group, a nitro group, a cyano group, an amine group, -COOH, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C2-C10 alkenyl group, a substituted or unsubstituted C1-C10 heteroalkyl group, a substituted or unsubstituted C2-C10 heteroalkenyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted C2-C20 heterocycloalkyl group, or a substituted or unsubstituted C6-C20 aryl group, for example, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, or a substituted or unsubstituted C6-C20 aryl group, for example, a substituted or unsubstituted C1-C5 alkyl group or a substituted or unsubstituted C3-C10 cycloalkyl group, but is not limited to these.

[0069] The structural unit represented by Chemical Formula 1 may be included in an amount of 20% to 80% by weight based on the total weight of the polymer. More specifically, the structural unit represented by Chemical Formula 1 may be included in an amount of 20% to 75% by weight based on the total weight of the polymer, for example, but not limited to, 20% to 70% by weight, 20% to 65% by weight, 20% to 60% by weight, 25% to 60% by weight, or 30% to 60% by weight. When the polymer contains the structural unit represented by Chemical Formula 1 in the above range, the sensitivity of the photoresist can be further improved.

[0070] The polymer may have a weight-average molecular weight (Mw) of 1,000 g / mol to 300,000 g / mol, for example, about 1,000 g / mol to 200,000 g / mol, for example, 1,000 g / mol to 100,000 g / mol, for example, 2,000 g / mol to 90,000 g / mol, for example, 2,000 g / mol to 70,000 g / mol, for example, 2,000 g / mol to 50,000 g / mol, for example, 5,000 g / mol to 50,000 g / mol, for example, 5,000 g / mol to 30,000 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 the resist underlayer film composition containing the polymer can be adjusted and optimized.

[0071] The polymer may be contained in an amount of 0.1 wt% to 50 wt% based on the total weight of the composition for a resist underlayer film. More specifically, the polymer may be contained in an amount of 0.1 wt% to 45 wt%, for example, 0.1 wt% to 40 wt%, 0.1 wt% to 35 wt%, 0.1 wt% to 30 wt%, 0.2 wt% to 30 wt%, 0.3 wt% to 30 wt%, 0.4 wt% to 30 wt%, or 0.5 wt% to 30 wt%, based on the total weight of the composition for a resist underlayer film, but is not limited thereto. By containing the polymer in the composition in the above range, the thickness, surface roughness, and degree of planarization of the resist underlayer film can be adjusted.

[0072] The resist underlayer film composition according to an embodiment may contain a solvent. The solvent is not particularly limited as long as it has sufficient solubility and / or dispersibility in the polymer according to an embodiment, and may include, but is not limited to, for example, 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 (PGMEA), cyclohexanone, ethyl lactate, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, methylpyrrolidone, methylpyrrolidinone, methyl 2-hydroxyisobutyrate, acetylacetone, ethyl 3-ethoxypropionate, or a combination thereof.

[0073] The composition for a resist underlayer film according to an embodiment may further include, in addition to the polymer and the solvent, one or more polymers selected from an acrylic resin, an epoxy resin, a novolac resin, a glycoluril resin, and a melamine resin, but is not limited thereto.

[0074] Furthermore, the composition for a resist underlayer film according to another embodiment may further include additives including a surfactant, a thermal acid generator, a photoacid generator, a plasticizer, or a combination thereof.

[0075] The surfactant may be used to improve coating defects that occur due to an increase in the solid content during the formation of the resist underlayer film. Examples of surfactants that may be used include, but are not limited to, alkylbenzene sulfonates, alkylpyridinium salts, polyethylene glycols, and quaternary ammonium salts.

[0076] 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 benzoin tosylate, 2-nitrobenzyl tosylate, and other organic sulfonic acid alkyl esters.

[0077] The plasticizer is not particularly limited, and various known plasticizers can be used. Examples of the plasticizer include low molecular weight compounds such as phthalates, adipic esters, phosphates, trimellitates, and citrates, as well as polyether, polyester, and polyacetal compounds.

[0078] The additive may be contained in an amount of 0.001 to 40 parts by weight relative to 100 parts by weight of the composition for a resist underlayer film. By containing the additive in the above range, the solubility of the composition for a resist underlayer film can be improved without changing the optical properties of the composition for a resist underlayer film.

[0079] According to another embodiment, there is provided a resist underlayer film produced using the resist underlayer film composition. The resist underlayer film may be in a form obtained by, for example, applying the resist underlayer film composition onto a substrate and then curing the composition through a heat treatment process.

[0080] Hereinafter, a method for forming a pattern using a composition for a resist underlayer film will be described with reference to FIG.

[0081] FIG. 1 is a cross-sectional view illustrating a pattern forming method using a resist underlayer film composition according to the present invention.

[0082] Referring to FIG. 1(a), first, an object to be etched is provided. An example of the object to be etched may be a thin film 102 formed on a substrate 100. Hereinafter, the description will be given assuming that the object to be etched is the thin film 102. The surface of the thin film 102 is pre-cleaned to remove contaminants remaining on the thin film 102. The thin film 102 may be, for example, a silicon nitride film, a polysilicon film, or a silicon oxide film.

[0083] Next, a resist underlayer film composition is applied onto the surface of the cleaned thin film 102 by spin coating.

[0084] Thereafter, drying and baking steps are performed to form a resist underlayer film 104 on the thin film 102. The baking process is performed at 100°C to 500°C, and can be performed at, for example, 100°C to 300°C. A more specific description of the composition for a resist underlayer film has been given above, and will be omitted here to avoid duplication.

[0085] Referring to FIG. 1(b), a photoresist is applied onto the resist underlayer film 104 to form a photoresist film 106.

[0086] Examples of photoresists include positive photoresists containing a naphthoquinone diazide compound and a novolak resin, chemically amplified positive photoresists containing an acid generator capable of dissociating an acid upon exposure, a compound that decomposes in the presence of acid to increase its solubility in an alkaline aqueous solution, and an alkali-soluble resin, and chemically amplified positive photoresists containing an acid generator and an alkali-soluble resin having a group that decomposes in the presence of acid to increase its solubility in an alkaline aqueous solution.

[0087] Next, a first baking step is performed to heat the substrate 100 on which the photoresist film 106 is formed. The first baking step can be performed at a temperature of 90°C to 120°C.

[0088] 1(c), the photoresist film 106 is selectively exposed. To explain the exposure process for exposing the photoresist film 106 as an example, an exposure mask having a predetermined pattern formed thereon is placed on a mask stage of an exposure tool, and the exposure mask 110 is aligned on the photoresist film 106. Next, light is irradiated onto the exposure mask 110, causing predetermined portions of the photoresist film 106 formed on the substrate 100 to selectively react with the light transmitted through the exposure mask.

[0089] Examples of light that can be used in the exposure process include short wavelength light such as i-line having a wavelength of 365 nm, KrF excimer laser having a wavelength of 248 nm, and ArF excimer laser having a wavelength of 193 nm, as well as extreme ultraviolet (EUV) having a wavelength of 13.5 nm.

[0090] The photoresist film 106a in the exposed area is relatively hydrophilic compared to the photoresist film 106b in the unexposed area, and therefore the photoresist film 106a in the exposed area and the photoresist film 106b in the unexposed area have different solubilities.

[0091] Next, a second baking process is performed on the substrate 100. The second baking process can be performed at a temperature of 90°C to 150°C. By performing the second baking process, the photoresist film in the unexposed region is additionally hardened, and when the film in the exposed region is removed by a developer, the unexposed region can be prevented from being removed together with the film in the exposed region or from swelling due to the developer.

[0092] Referring to FIG. 1(d), specifically, the photoresist film 106a in the exposed region is dissolved and then removed using tetramethyl ammonium hydroxide (TMAH) or the like, and the photoresist film 106b remaining after development forms the photoresist pattern 108.

[0093] Next, the resist underlayer film 104 is etched using the photoresist pattern 108 as an etching mask. This etching process forms an organic film pattern 112 as shown in FIG. 1(e). The etching can be performed, for example, by dry etching using an etching gas, such as CHF, CF, Cl, O, or a mixture thereof. As described above, the resist underlayer film formed using the resist underlayer film composition according to one embodiment has a high etching rate, allowing smooth etching to be performed in a short time.

[0094] 1(f), the exposed thin film 102 is etched using the photoresist pattern 108 as an etching mask. As a result, the thin film is formed into a thin film pattern 114. The thin film pattern 114 formed by the previous exposure process using a short wavelength light source such as i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), or ArF excimer laser (wavelength 193 nm) may have a width of several tens to several hundreds of nm, and the thin film pattern 114 formed by the exposure process using an EUV light source may have a width of 20 nm or less.

[0095] The present invention will be described in more detail below through examples of the synthesis of the above-mentioned polymer and the preparation of a composition for a resist underlayer film containing the same. However, the technical features of the present invention are not limited to the following examples.

[0096] (Synthesis example) (Synthesis Example 1) A 500ml three-neck round-bottom flask was charged with 4.9g of glycidyl methacrylate (Aldrich), 4.9g of propyl methacrylate (Aldrich), 4.8g of dimethyl 2,2'-azobis(2-methylpropionate) (V-601; TCI), and 64g of propylene glycol methyl ether acetate (PGMEA) to prepare a reaction solution, and a condenser was connected. The reaction solution was heated to 90°C for 1 hour and then cooled to room temperature (23°C). The reaction solution was then added dropwise to a beaker containing 450g of heptane while stirring to form a gum, which was then dissolved in 90g of DMF (dimethyl formamide).

[0097] A 500ml three-neck round-bottom flask was charged with 80.0g of the intermediate product obtained above, 9.0g of 2-iodopropionic acid, 0.5g of pyridine, and 0.5g of butylated hydroxytoluene (BHT) to prepare a reaction solution, and a condenser was connected. The reaction solution was heated to 80°C for 4 hours and then cooled to room temperature. The reaction solution was then added dropwise to a beaker containing 450g of heptane while stirring to form a gum, which was then dissolved in 90.0g of PGMEA. The solution was then used to remove monomolecular and small molecules, and dried to obtain a polymer consisting of structural units represented by the following formulas 1-2 and 2-1. (Mw: 8,200g / mol)

[0098] [Chemical formula 1-2] [ka]

[0099] [Chemical formula 2-1] [ka]

[0100] (Synthesis Example 2) Under a nitrogen atmosphere, 41.0 g of cyclohexyl methacrylate and 31.61 g of PGMEA were placed in a 500 ml two-neck round-bottom flask, connected to a condenser, and heated to 80°C. 20.5 g of glycidyl methacrylate (TCI) and 12.5 g of dimethyl 2,2'-azobis(2-methylpropionate) were dissolved in 82.43 g of PGMEA and added dropwise over one hour. The mixture was allowed to react for three hours and then cooled to room temperature. The reaction solution was then transferred to a 1 L wide-mouth bottle and 450 g of heptane was added with stirring to form a gum, which was then dissolved in 150 g of THF. The solution was then used to remove monomolecular and small molecules, dried, and dissolved in 90 g of DMF.

[0101] A 500ml three-neck round-bottom flask was charged with 80.0g of the intermediate product obtained above, 13.0g of 2,3-diiodobutanoic acid, 0.5g of pyridine, and 0.5g of BHT to prepare a reaction solution, and a condenser was connected. The reaction solution was heated to 80°C for 4 hours and allowed to react, then cooled to room temperature. The reaction solution was then added dropwise to a beaker containing 450g of heptane while stirring to produce a gum, which was then dissolved in 90.0g of PGMEA. The solution was then used to remove monomolecular and small molecules, and dried to obtain a polymer consisting of structural units represented by the following formulas 1-3 and 2-2. (Mw: 11,000g / mol)

[0102] [Chemical formula 1-3] [ka]

[0103] [Chemical formula 2-2] [ka]

[0104] (Synthesis Example 3) Under a nitrogen atmosphere, 30.0 g of methyl methacrylate and 41.61 g of PGMEA were placed in a 500 ml two-neck round-bottom flask, connected to a condenser, and heated to 80°C. 15.25 g of glycidyl methacrylate (TCI) and 12.5 g of dimethyl 2,2'-azobis(2-methylpropionate) were dissolved in 82.43 g of PGMEA and added dropwise over one hour. The mixture was allowed to react for three hours and then cooled to room temperature. The reaction solution was then transferred to a 1 L wide-mouth bottle and 450 g of heptane was added with stirring to form a gum, which was then dissolved in 150 g of THF. The resulting solution was then used to remove monomolecular and small molecules, dried, and dissolved in 90.0 g of DMF.

[0105] A 500ml three-neck round-bottom flask was charged with 80.0g of the intermediate product obtained above, 15.0g of α-iodophenylacetic acid, 0.5g of pyridine, and 0.5g of BHT to prepare a reaction solution, and a condenser was connected. The reaction solution was heated to 80°C for 4 hours and then cooled to room temperature. The reaction solution was then added dropwise to a beaker containing 450g of heptane while stirring to produce a gum, which was then dissolved in 90.0g of PGMEA. The solution was then used to remove monomolecular and small molecules, and dried to obtain a polymer consisting of structural units represented by the following chemical formulas 1-4 and 2-3. (Mw: 13,000g / mol)

[0106] [Chemical formula 1-4] [ka]

[0107] [Chemical formula 2-3] [ka]

[0108] (Synthesis Example 4) A reaction solution was prepared by adding 10.0 g of 1-adamantaneacetic acid (Aldrich), 50.0 g of thionyl chloride (Aldrich), and 2.0 g of iodine (Aldrich) to a 250 ml two-neck round-bottom flask and connecting a condenser. The reaction solution was heated to 65°C for 3 hours and then cooled to room temperature. The reaction solution was then added dropwise to a beaker containing 200 g of deionized water (DIW) while stirring, and the DIW was removed. 200 g of DIW and 200 g of THF were then added to the beaker, stirred, and dried to obtain reaction product (A).

[0109] A 500ml three-neck round-bottom flask was charged with 15.5g of tert-butyl methacrylate (TCI), 15.25g of glycidyl acrylate (TCI), 4.8g of dimethyl 2,2'-azobis(2-methylpropionate), and 64g of PGMEA to prepare a reaction solution, and a condenser was connected. The reaction solution was heated to 90°C for 1 hour and then cooled to room temperature. The reaction solution was then added dropwise to a beaker containing 450g of heptane while stirring to form a gum, which was then dissolved in 90g of DMF. The solution was then used to remove monomolecular and small molecules, yielding polymer (B).

[0110] A reaction solution was prepared by adding 5.0 g of reactant (A), 30.0 g of polymer (B), 0.3 g of pyridine, and 0.3 g of BHT to a 250 ml three-neck round-bottom flask and connecting a condenser. The reaction solution was heated to 80°C for 4 hours and then cooled to room temperature. The reaction solution was then added dropwise to a beaker containing 450 g of heptane while stirring to form a gum, which was then dissolved in 90.0 g of PGMEA. After removing monomolecular and small molecules from the solution using heptane, a polymer consisting of structural units represented by the following chemical formulas 1-5 and 2-4 was finally obtained. (Mw: 8,200 g / mol)

[0111] [Chemical formula 1-5] [ka]

[0112] [Chemical formula 2-4] [ka]

[0113] (Comparative Synthesis Example 1) Under a nitrogen atmosphere, 30.0 g of methyl methacrylate and 41.61 g of PGMEA were placed in a 500 ml two-neck round-bottom flask, connected to a condenser, and heated to 80°C. 15.25 g of glycidyl acrylate and 12.5 g of dimethyl 2,2'-azobis(2-methylpropionate) were dissolved in 82.43 g of PGMEA and added dropwise over one hour, then allowed to react for three hours and cooled to room temperature. The reaction solution was then transferred to a 1 L wide-mouth bottle, and 450 g of heptane was added with stirring to form a gum, which was then dissolved in 150 g of THF. The solution was then dried using heptane to remove monomolecular and small molecules, yielding a copolymer consisting of structural units represented by the following formulas: 2-3 and 2-4 (Mw = 12,000 g / mol).

[0114] [Chemical formula 2-3] [ka]

[0115] [Chemical formula 2-4] [ka]

[0116] (Comparative Synthesis Example 2) Under a nitrogen atmosphere, 20.0 g of hydroxypropyl methacrylate and 40.0 g of PGMEA were placed in a 500 ml two-neck round-bottom flask, connected to a condenser, and heated to 80°C. 15.0 g of glycidyl acrylate and 10.0 g of dimethyl 2,2'-azobis(2-methylpropionate) were dissolved in 80.0 g of PGMEA and added dropwise over one hour. The mixture was allowed to react for three hours and then cooled to room temperature. The reaction solution was then transferred to a 1 L wide-mouth bottle, and 450 g of heptane was added with stirring to form a gum, which was then dissolved in 150 g of THF. The resulting solution was then used to remove monomolecular and small molecules using heptane, dried, and dissolved in 90.0 g of DMF.

[0117] A reaction solution was prepared by adding 80.0 g of the intermediate product obtained above, 15.0 g of 3-iodopropanoic acid, 0.5 g of pyridine, and 0.5 g of BHT to a 500 ml three-neck round-bottom flask and connecting a condenser. The reaction solution was heated to 80°C for 4 hours and then cooled to room temperature. The reaction solution was then added dropwise to a beaker containing 450 g of heptane while stirring to form a gum, which was then dissolved in 90.0 g of PGMEA. After removing monomolecular and small molecules from the solution using heptane, a copolymer consisting of structural units represented by the following formulas 3 and 2-5 was finally obtained (Mw = 9,800 g / mol).

[0118] [Chemical formula 3] [ka]

[0119] [Chemical formula 2-5] [ka] (Comparative Synthesis Example 3) Under a nitrogen atmosphere, 30.0 g of methyl methacrylate and 40.0 g of PGMEA were placed in a 500 ml two-neck round-bottom flask, connected to a condenser, and heated to 80°C. 15.0 g of glycidyl acrylate and 10.0 g of dimethyl 2,2'-azobis(2-methylpropionate) were dissolved in 80.0 g of PGMEA and added dropwise over one hour. The mixture was then allowed to react for three hours and cooled to room temperature. The reaction solution was then transferred to a 1 L wide-mouth bottle, and 450 g of heptane was added with stirring to form a gum, which was then dissolved in 150 g of THF. The resulting solution was then used to remove monomolecular and small molecules, dried, and dissolved in 90.0 g of DMF.

[0120] A reaction solution was prepared by adding 80.0 g of the intermediate product obtained above, 18.0 g of α,α-difluorophenylacetic acid, 0.5 g of pyridine, and 0.5 g of BHT to a 500 ml three-neck round-bottom flask and connecting a condenser. The reaction solution was heated to 80°C for 4 hours and then cooled to room temperature. The reaction solution was then added dropwise to a beaker containing 450 g of heptane while stirring to form a gum, which was then dissolved in 90.0 g of PGMEA. After removing monomolecular and small molecules from the solution using heptane, a copolymer consisting of structural units represented by the following formulas 4 and 2-3 was finally obtained. (Mw=13,500 / mol)

[0121] [Chemical formula 4] [ka]

[0122] [Chemical formula 2-3] [ka]

[0123] (Production of composition for resist underlayer film) Examples and Comparative Examples The polymers, crosslinker (PL1174), and thermal acid generator (TAG) (pyridinium p-poluenesulfonate; PPTS) prepared in the above Synthesis Examples and Comparative Synthesis Examples were each dissolved in PGMEA to a solids concentration of 2 wt %. The resulting solution was diluted with methyl 2-hydroxyisobutyrate to prepare resist underlayer film compositions having a solids concentration of 1 wt % based on the total weight of the entire composition, as shown in Table 1 below. The respective contents in Table 1 below are in wt % based on the total weight of the resist underlayer film composition.

[0124] [Table 1]

[0125] (Evaluation 1: Line width roughness (LWR) evaluation) The compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were each spin-coated and then heat-treated on a hot plate at 205°C for 60 seconds to form a 50 Å thick resist underlayer film. A photoresist solution was then spin-coated onto the underlayer film and heat-treated on a hot plate at 110°C for 1 minute to form a photoresist layer. The resist layer was exposed using an e-beam exposure tool (Elionix, accelerating voltage 100 keV). The resist layer was then heat-treated at 95°C for 60 seconds, developed in a 2.38 wt% TMAH aqueous solution for 60 seconds, and rinsed with pure water for 15 seconds to form a resist pattern.

[0126] The line width roughness (LWR) was measured by observing the formed pattern with a scanning electron microscope (SEM) S-9260 (manufactured by Hitachi) and measuring the distance that the edge deviated from the reference line within a 2 μm range from the edge in the longitudinal direction of the pattern.

[0127] The evaluation values ​​of the exposure dose and LWR measured in the Examples and Comparative Examples as described above were converted into a ratio based on the exposure dose or LWR of Comparative Example 1 as shown in the following formula. The results are shown in Table 2 below. The smaller the exposure dose and LWR values, the better the pattern formability and sensitivity.

[0128] *Exposure (or LWR) (%) = (Exposure (or LWR) in each Example - Exposure (or LWR) in Comparative Example 1) / Exposure (or LWR) in Comparative Example 1 x 100

[0129] [Table 2]

[0130] Referring to Table 2, it can be seen that the photoresist films according to the Examples are cured with a smaller exposure dose than the photoresist films according to the Comparative Examples, and therefore the photoresist films according to the Examples have better sensitivity than the Comparative Examples. It can also be seen that the photoresist films according to the Examples have a smaller LWR than the Comparative Examples, and therefore have more uniform patterns.

[0131] As a result, it can be confirmed that the compositions according to the examples, which contain a polymer containing a structural unit in which iodine is substituted on the carbon atom to which a terminal functional group is bonded, have superior sensitivity compared to Comparative Examples 1 to 3 and can form photoresist films with more uniform patterns.

[0132] (Evaluation 2: Evaluation of storage stability) The resist underlayer film compositions according to the Examples and Comparative Examples were stored at 35°C for one month, and the presence or absence of precipitates was visually inspected after one month of storage to evaluate storage stability. If no precipitates were formed, it meant that the storage stability was excellent, and the results are shown in Table 3 below.

[0133] [Table 3]

[0134] Referring to Table 3, the resist underlayer film composition according to the Example did not produce any precipitate even after one month of storage, whereas the resist underlayer film compositions according to Comparative Examples 2 and 3 produced precipitates after one month of storage, demonstrating that the compositions according to the Examples have excellent storage stability.

[0135] Although specific embodiments of the present invention have been described and illustrated above, it will be apparent to those skilled in the art that the present invention is not limited to the described embodiments, and that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, such modifications or variations should not be understood individually from the technical spirit and perspective of the present invention, and the modified embodiments should be considered to fall within the scope of the claims of the present invention. [Explanation of symbols]

[0136] 100: Substrate 102: Thin film 104: Resist underlayer film 106: Photoresist film 106a: exposure area 106b: Non-exposed area 108: Photoresist pattern 110: Mask 112: Organic film pattern 114: Thin film pattern

Claims

1. A composition for a resist underlayer film, comprising: a polymer containing a structural unit represented by the following chemical formula 1; and a solvent. [Chemical formula 1] 【Chemistry 1】 (In the above Chemical Formula 1, R １ ~R ３ are each independently hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group; L １ is a single bond, a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C2 to C10 alkenylene group, a substituted or unsubstituted C2 to C10 alkynylene group, a substituted or unsubstituted C1 to C10 heteroalkylene group, a substituted or unsubstituted C2 to C10 heteroalkenylene group, or a combination thereof; X １ represents a single bond, —O—, —C(═O)—, —(CO)O—, —O(CO)O—, —NR ａ - (where R ａ is hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group; or a combination thereof; Y １ is *-(CH ２ )n-(CHI)m-CR ｘ R ｙ R ｚ (where n is an integer from 0 to 5, m is 0 or 1, and R ｘ ~R ｚ are each independently a hydrogen, deuterium, or halogen atom; a substituted or unsubstituted C3 to C20 cycloalkyl group, two or more fused rings of a substituted or unsubstituted C3 to C10 cycloalkyl group, a substituted or unsubstituted C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a substituted or unsubstituted C2 to C20 heteroaryl group; * indicates a connection point.)

2. L of Formula 1 １ is a substituted or unsubstituted C1-C10 alkylene group, and X １ The composition for a resist underlayer film according to claim 1, wherein is —(CO)O—.

3. 2. The resist underlayer film composition according to claim 1, wherein the polymer comprises a structural unit represented by the following chemical formula 1-1: [Chemical formula 1-1] 【Chemistry 2】 (In the above chemical formula 1-1, R ４ is hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group; Y ２ is a substituted or unsubstituted methyl group, -CHICH ３ a substituted or unsubstituted C3 to C20 cycloalkyl group, two or more fused rings of a substituted or unsubstituted C3 to C10 cycloalkyl group, or a substituted or unsubstituted C6 to C10 aryl group; * indicates a connection point.)

4. The composition for a resist underlayer film according to claim 1 , wherein the polymer further comprises a structural unit represented by the following chemical formula 2: [Chemical formula 2] 【Transformation 3】 (In the above chemical formula 2, R ５ ~R ７ are each independently hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group; X ２ and X ３ are each independently a single bond, —O—, —S—, —S(═O)—, or —S(═O) ２ -, -C(=O)-, -(CO)O-, -O(CO)O-, -NR ｂ - (where R ｂ is hydrogen, deuterium, or a C1-C10 alkyl group; or a combination thereof; L ２ is a single bond, a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C1 to C10 heteroalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C2 to C20 heterocycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C2 to C20 heteroarylene group, or a combination thereof; Y ３ is hydrogen, deuterium, a hydroxy group, a nitro group, a cyano group, an amine group, —COOH, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C2-C10 alkenyl group, a substituted or unsubstituted C2-C10 alkynyl group, a substituted or unsubstituted C1-C10 heteroalkyl group, a substituted or unsubstituted C2-C10 heteroalkenyl group, a substituted or unsubstituted C2-C10 heteroalkynyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted C2-C20 heterocycloalkyl group, a substituted or unsubstituted C6-C20 aryl group, or a substituted or unsubstituted C2-C20 heteroaryl group; * indicates a connection point.)

5. X in Formula 2 ２ is —(CO)O—, and X ３ is a single bond, and Y ３ is a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, or a substituted or unsubstituted C6 to C20 aryl group.

6. 2. The resist underlayer film composition according to claim 1, wherein the polymer comprises one or more structural units represented by the following chemical formulas 1-2 to 1-5: [Chemical formula 1-2] 【Chemistry 4】 [Chemical formula 1-3] 【Transformation 5】 [Chemical formula 1-4] 【Transformation 6】 [Chemical formula 1-5] 【Transformation 7】

7. 2. The composition for a resist underlayer film according to claim 1, wherein the structural unit represented by Chemical Formula 1 is present in an amount of 20% by weight to 80% by weight based on the total weight of the polymer.

8. 2. The resist underlayer film composition according to claim 1, wherein the polymer has a weight average molecular weight of 1,000 g / mol to 300,000 g / mol.

9. 2. The composition for a resist underlayer film according to claim 1, wherein the polymer is contained in an amount of 0.1% by weight to 50% by weight based on the total weight of the composition for a resist underlayer film.

10. 2. The resist underlayer film composition according to claim 1, further comprising one or more polymers selected from the group consisting of acrylic resins, epoxy resins, novolac resins, glycoluril resins, and melamine resins.

11. The resist underlayer film composition according to claim 1 , further comprising an additive selected from the group consisting of a surfactant, a thermal acid generator, a photoacid generator, a plasticizer, and a combination thereof.

12. forming a film to be etched on a substrate; Applying the composition for a resist underlayer film according to any one of claims 1 to 11 onto the film to be etched to form a resist underlayer film; forming a photoresist pattern on the resist underlayer film; sequentially etching the resist underlayer film and the etching target film using the photoresist pattern as an etching mask; A pattern forming method comprising:

Images