Composition for resist underlayer film and pattern forming method using the same

Abstract

To provide a composition for the production of a resist underlayer that does not cause resist pattern collapse even in a fine patterning process and has improved sensitivity to an exposure light source, thereby improving patterning performance and energy efficiency.SOLUTION: A composition for a resist underlayer film comprises: a polymer containing a structural unit represented by the following chemical formula, a specific structural unit, or a combination thereof; a radical initiator having a bond dissociation energy of 0 to 60 kcal / mol; and a solvent.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention 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 evolved from patterns of several hundred nanometers to ultrafine technologies with patterns of several to several tens of nanometers. To realize such ultrafine technologies, effective lithographic methods are essential.

[0003] Lithographic techniques are a processing method in which a thin film is formed by coating a photoresist film on a semiconductor substrate such as a silicon wafer, and then the thin film is irradiated with activating radiation such as ultraviolet 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 surface of the substrate that corresponds to the pattern.

[0004] As semiconductor patterns become increasingly finer, thinner photoresist layers are required, which in turn requires thinner resist underlayers. A resist underlayer must not collapse the photoresist pattern even at a thin thickness, have good adhesion to the photoresist, and be formed to a uniform thickness. Additionally, resist underlayers are required to have improved sensitivity, such as a high refractive index and a low absorption coefficient, to the light source used in photolithography. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Korean Patent Publication No. 10-2023-0020811 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a composition for producing a resist underlayer film that does not cause resist pattern collapse even in a fine patterning process, has improved sensitivity to an exposure light source, and has improved patterning performance and energy efficiency.

[0007] An object of the present invention is to provide a pattern forming method using the above-mentioned composition for a resist underlayer film. [Means for solving the problem]

[0008] 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, a structural unit represented by the following chemical formula 2, or a combination thereof, a radical initiator having a bond dissociation energy (BDE) of 0 to 60 kcal / mol, and a solvent.

[0009] [ka] ...chemical formula 1

[0010] [ka] ...Chemical formula 2

[0011] In the above Chemical Formula 1 and Chemical Formula 2, A is a heterocyclic group containing a nitrogen atom in the ring, L 1 ~L 6 are each independently 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 C3-C20 heteroarylene group, or a combination thereof; X1 ~X 5 each independently represents a single bond, -O-, -S-, -S(=O)-, -S(=O)2-, -C(=O)-, -(CO)O-, -O(CO)O-, or -NR a -(where R a is hydrogen, deuterium, or a C1-C10 alkyl group), or a combination thereof; Y 1 ~Y 3 are each independently a hydroxy group, 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, a substituted or unsubstituted C3-C20 heteroaryl group, or a combination thereof; * is the attachment point.

[0012] The A is represented by one or more of the following chemical formulas A-1 to A-4.

[0013] [ka] ...Chemical formula A-1

[0014] [ka] ...Chemical formula A-2

[0015] [ka] ...Chemical formula A-3

[0016] [ka] ...Chemical formula A-4

[0017] In the chemical formulas A-1 to A-4, the R x is hydrogen, deuterium, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, or a substituted or unsubstituted C2 to C10 alkynyl group, and * is the point of attachment.

[0018] Said L 1 ~L 6 are each independently a single bond, a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C1-C10 heteroalkylene group, or a combination thereof; X 1 ~X 5 are each independently a single bond, -O-, -S-, -C(=O)-, -(CO)O-, -O(CO)O-, or a combination thereof; Y 1 ~Y 3 are each independently a hydroxy group, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, a substituted or unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted C2 to C10 heteroalkenyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a combination thereof.

[0019] The radical initiator is represented by any one of the following Chemical Formulas 3-1 to 3-4.

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

[0021] [ka] ...Chemical formula 3-2

[0022] [ka] ...Chemical formula 3-3

[0023] [ka] ...Chemical formula 3-4

[0024] In Chemical Formula 3-1 to Chemical Formula 3-4, R 1 ~R 5 are each independently a hydroxy group, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a combination thereof; R 6 ~R 9 are each independently hydrogen, deuterium, a hydroxy group, a substituted or unsubstituted C1 to C20 alkyl group, or a combination thereof; R a and R b are each independently deuterium, a hydroxy group, —SCH3, a substituted or unsubstituted C1 to C20 alkyl group, or a combination thereof; na and nb are each independently an integer of 0 to 5;

[0025] The radical initiator is represented by one or more of the following chemical formulas 4 to 10.

[0026] [ka] ...chemical formula 4

[0027] [ka] ...chemical formula 5

[0028] [ka] ...chemical formula 6

[0029] [ka] ...chemical formula 7

[0030] [ka] ...chemical formula 8

[0031] [ka] ...chemical formula 9

[0032] [ka] ...chemical formula 10

[0033] The chemical formula 1 is represented by the following chemical formula 1-1 or 1-2, and the chemical formula 2 is represented by any one of the following chemical formulas 2-1 to 2-3.

[0034] [ka] ...Chemical formula 1-1

[0035] [ka] ...Chemical formula 1-2

[0036] [ka] ...Chemical formula 2-1

[0037] [ka] ...Chemical formula 2-2

[0038] [ka] ...Chemical formula 2-3

[0039] The weight average molecular weight of the polymer is 1,000 g / mol to 300,000 g / mol.

[0040] 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.

[0041] The radical initiator is contained in an amount of 0.01% by weight to 30% by weight based on the total weight of the composition for a resist underlayer film.

[0042] The resist underlayer film composition may further include one or more polymers selected from an acrylic resin, an epoxy resin, a novolac resin, a glycouril resin, and a melamine resin.

[0043] The resist underlayer film composition may further include an additive such as a surfactant, a thermal acid generator, a photoacid generator, a plasticizer, or a combination thereof.

[0044] According to another embodiment, there is provided a pattern forming method including: 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 gradually etching the resist underlayer film and the film to be etched using the photoresist pattern as an etching mask. [Effects of the Invention]

[0045] The composition for a resist underlayer film according to one embodiment can provide a resist underlayer film having improved adhesion to the resist, preventing pattern collapse even in a fine patterning process, and improved sensitivity to an exposure light source, thereby improving patterning performance and energy efficiency. [Brief explanation of the drawings]

[0046] [Figure 1] 1 is a cross-sectional view illustrating a pattern forming method using a resist underlayer film composition according to one embodiment. [Figure 2] 1 is a cross-sectional view illustrating a pattern forming method using a resist underlayer film composition according to one embodiment. [Figure 3] 1 is a cross-sectional view illustrating a pattern forming method using a resist underlayer film composition according to one embodiment. [Figure 4] 1 is a cross-sectional view illustrating a pattern forming method using a resist underlayer film composition according to one embodiment. [Figure 5] 1 is a cross-sectional view illustrating a pattern forming method using a resist underlayer film composition according to one embodiment. [Figure 6] 1 is a cross-sectional view illustrating a pattern forming method using a resist underlayer film composition according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0047] 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 implement and practice the present invention. However, as the present invention may be embodied in many different forms, it is not limited to the embodiments set forth herein.

[0048] In the drawings, the thickness of various layers and regions is exaggerated for clarity, and similar parts are designated by the same reference numerals throughout the specification. When a layer, film, region, plate, or other part is said to be "on" another part, this includes not only the case where it is "directly on" that other part, but also the case where there is another part between them. Conversely, when a part is said to be "directly on" another part, it means that there is no other part between them.

[0049] 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 azido group, an amidino group, a hydrazino group, a hydrazono group, a carbonyl group, a carbamyl 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.

[0050] Furthermore, two adjacent substituents among the substituted halogen atoms (F, Br, Cl, or I), hydroxy groups, nitro groups, cyano groups, amino groups, azido groups, amidino groups, hydrazino groups, hydrazono groups, carbonyl groups, carbamyl groups, thiol groups, ester groups, carboxyl groups or salts thereof, sulfonic acid groups or salts thereof, phosphoric acid or salts thereof, C1-C30 alkyl groups, C2-C30 alkenyl groups, C2-C30 alkynyl groups, C6-C30 aryl groups, C7-C30 arylalkyl groups, C1-C30 alkoxy groups, C1-C20 heteroalkyl groups, C3-C20 heteroarylalkyl groups, C3-C30 cycloalkyl groups, C3-C15 cycloalkenyl groups, C6-C15 cycloalkynyl groups, and C2-C30 heterocyclic groups may be bonded to form a ring.

[0051] As used herein, the term "aryl group" refers to a group having one or more hydrocarbon aromatic moieties, and broadly includes both hydrocarbon aromatic moieties bonded by a single bond and non-aromatic fused rings to which hydrocarbon aromatic moieties are directly or indirectly fused. Aryl groups include monocyclic, polycyclic, or fused polycyclic (i.e., rings sharing adjacent pairs of carbon atoms) functional groups.

[0052] More specifically, the substituted or unsubstituted aryl group may be, but is not limited to, 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 perylenyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted indenyl group, a combination thereof, or a fused form of a combination thereof.

[0053] Unless otherwise defined herein, "hetero" means containing 1 to 3 heteroatoms selected from N, O, S, Se, and P.

[0054] As used herein, the term "heteroalkyl group" refers to a group that contains a heteroatom selected from the group consisting of N, O, S, P, and Si in place of one or more carbon atoms forming the alkyl group.

[0055] As used herein, the term "heteroaryl group" refers to an aryl group containing at least one heteroatom selected from the group consisting of N, O, S, P, and Si. Two or more heteroaryl groups may be directly bonded by a sigma bond, or, if the heteroaryl group contains two or more rings, the two or more rings may be fused to each other. If the heteroaryl group is a fused ring, each ring may contain one or more heteroatoms.

[0056] More specifically, the substituted or unsubstituted heteroaryl group is 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 group, a substituted or unsubstituted pyrazinyl 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 benzophenone ... The alkyl group may be, but is not limited to, a substituted or unsubstituted phenyl group, a substituted or unsubstituted isoquinolinyl group, a substituted or unsubstituted quinazolinyl group, a substituted or unsubstituted quinoxalinyl group, a substituted or unsubstituted naphthyrinidyl group, a substituted or unsubstituted benzoxazinyl group, a substituted or unsubstituted benzthiazinyl group, a substituted or unsubstituted acridinyl group, a substituted or unsubstituted phenazinyl group, a substituted or unsubstituted phenothiazinyl group, a substituted or unsubstituted phenoxazinyl 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.

[0057] Unless otherwise specified herein, "combination" means blending or copolymerization.

[0058] In addition, in this specification, the term "polymer" can include both oligomers and polymers.

[0059] 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).

[0060] Also, unless otherwise defined herein, "*" refers to a structural unit of a compound or a point of attachment of a compound moiety.

[0061] The semiconductor industry continues to demand smaller chip sizes. To meet this trend, the linewidth of resists patterned in lithography must be reduced to the order of a few tens of nanometers. This pattern is then used to transfer the pattern to an underlying material through an etching process. 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.

[0062] The resist underlayer film must be thinner as the resist thickness decreases, and the photoresist pattern must not collapse even at a thin resist underlayer film. To achieve this, 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 therefrom must be improved, and the sensitivity to the exposure light source must be improved to improve pattern formability and energy efficiency.

[0063] According to one embodiment, the composition for an underlayer film includes a polymer including a structural unit represented by the following Chemical Formula 1, a structural unit represented by the following Chemical Formula 2, or a combination thereof, a radical initiator having a bond dissociation energy of 0 to 60 kcal / mol, and a solvent.

[0064] [ka] ...chemical formula 1

[0065] [ka] ...Chemical formula 2

[0066] In the above Chemical Formula 1 and Chemical Formula 2, A is a heterocyclic group containing a nitrogen atom in the ring, L 1 ~L 6 are each independently 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 C1-C20 heteroarylene group, or a combination thereof; X 1 ~X 5 each independently represents a single bond, -O-, -S-, -S(=O)-, -S(=O)2-, -C(=O)-, -(CO)O-, -O(CO)O-, or -NR a -(where R a is hydrogen, deuterium, or a C1-C10 alkyl group), or a combination thereof; Y 1 ~Y 3are each independently a hydroxy group, 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 C1-C10 heteroalkenyl group, a substituted or unsubstituted C1-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, a substituted or unsubstituted C3-C20 heteroaryl group, or a combination thereof; * is the attachment point.

[0067] In addition, the polymer contained in the underlayer film composition according to one embodiment contains a heterocycle containing a nitrogen atom in the ring, and therefore, the polymer containing these structural units has sp 2 -sp 2 The polymer can bond to the resist underlayer film. This allows the polymer to have high electron density. By including a polymer with high electron density, an underlayer film composition according to one embodiment can realize a film with a dense structure in the form of an ultrathin film. In addition, the high electron density of the polymer can have the effect of improving the absorption efficiency during exposure of the resist underlayer film composition. Furthermore, the polymer containing the heterocyclic skeleton has excellent etching selectivity and can improve energy efficiency during pattern formation after exposure using high-energy rays such as EUV (Extreme ultraviolet; wavelength 13.5 nm) and E-Beam (electron beam).

[0068] The composition for an underlayer film according to one embodiment includes a radical initiator having a bond dissociation energy within the specific range as described above, and thereby can covalently bond with radicals generated from the photoresist during exposure, thereby improving adhesion between the photoresist and the resist underlayer film. Furthermore, by rapidly removing unnecessary radicals from the photoresist, the composition for an underlayer film can improve resist sensitivity and improve fine pattern formability.

[0069] A in the structural unit forming the polymer is represented by one or more of the following chemical formulae A-1 to A-4.

[0070] [ka] ...Chemical formula A-1

[0071] [ka] ...Chemical formula A-2

[0072] [ka] ...Chemical formula A-3

[0073] [ka] ...Chemical formula A-4

[0074] In the chemical formulas A-1 to A-4, the R x is hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C2-C10 alkenyl group, or a substituted or unsubstituted C2-C10 alkynyl group, for example, hydrogen or a substituted or unsubstituted C1-C5 alkyl group, and * is the point of attachment.

[0075] L of Chemical Formula 1 and Chemical Formula 2 1 ~L 6 are each independently 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, but not limited to, a single bond, a substituted or unsubstituted C1-C5 alkylene group, a substituted or unsubstituted C1-C5 heteroalkylene group, or a combination thereof.

[0076] X in the above Chemical Formula 1 and Chemical Formula 2 1 ~X 5 are each independently a single bond, —O—, —S—, —C(═O)—, —(CO)O—, —O(CO)O—, or a combination thereof, for example, but not limited to, a single bond, —C(═O)O—, —OC(═O)—, or —S—.

[0077] Y in the above Chemical Formula 1 and Chemical Formula 2 1 ~Y 3 are each independently a hydroxy group, 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, a substituted or unsubstituted C6-C20 aryl group, or a combination thereof, such as a hydroxy group, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C2-C10 alkenyl group, or a combination thereof, such as, but not limited to, a hydroxy group, a substituted or unsubstituted C1-C5 alkyl group, a substituted or unsubstituted C2-C5 alkenyl group, or a combination thereof.

[0078] As an example, the chemical formula 1 is represented by the following chemical formula 1-1 or chemical formula 1-2, and the chemical formula 2 is represented by any one of the following chemical formulas 2-1 to 2-3.

[0079] [ka] ...Chemical formula 1-1

[0080] [ka] ...Chemical formula 1-2

[0081] [ka] ...Chemical formula 2-1

[0082] [ka] ...Chemical formula 2-2

[0083] [ka] ...Chemical formula 2-3

[0084] In the above chemical formulas 1-1, 1-2, and 2-1 to 2-3, * represents a bonding point.

[0085] The bond dissociation energy of the radical initiator contained in the composition is 0 to 60 kcal / mol, for example, 0 to 55 kcal / mol, for example, 0 to 50 kcal / mol, for example, 0 to 45 kcal / mol, for example, 0 to 40 kcal / mol, but is not limited thereto. When the bond dissociation energy of the radical initiator is within this range, bonds within the radical initiator can be decomposed to form radicals upon exposure to short-wavelength light such as the 365 nm activation i-line, the 248 nm KrF excimer laser, the 193 nm ArF excimer laser, and the 13.5 nm EUV (Extreme ultraviolet). The radicals thus formed covalently bond with radicals within the photoresist, thereby improving adhesion between the photoresist and the resist underlayer film.

[0086] The radical initiator is not limited to a specific compound, and any radical initiator known in the art can be used as long as it can be decomposed by light having energy equivalent to the bond dissociation energy to form a radical.

[0087] Bond dissociation energy (BDE) is the energy required for the equilibrium decomposition of a chemical bond, specifically the energy required for the equilibrium decomposition of the most fragile bond in a compound. In this specification, bond dissociation energy is calculated using Jaguar software (DFT(b3lyp-d3)6-31g++**Jaguar software) with a dispersion term added to a B3LYP hybrid function containing an effective core potential and the 6-31g++** basis set.

[0088] The radical initiator is represented by any one of the following chemical formulas 3-1 to 3-4.

[0089] [ka] ...Chemical formula 3-1

[0090] [ka] ...Chemical formula 3-2

[0091] [ka] ...Chemical formula 3-3

[0092] [ka] ...Chemical formula 3-4

[0093] In the above Chemical Formulas 3-1 to 3-4, R 1 ~R 5are each independently a hydroxy group, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted C6-C20 aryl group, or a combination thereof, such as a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted C6-C20 aryl group, or a combination thereof, such as, but not limited to, a C1-C10 alkyl group substituted with a heterocyclic group, a substituted or unsubstituted C1-C10 alkoxy group, a C3-C10 cycloalkyl group substituted with a hydroxy group, a substituted or unsubstituted C6-C10 aryl group, or a combination thereof.

[0094] R 6 ~R 9 are each independently hydrogen, deuterium, a hydroxy group, a substituted or unsubstituted C1 to C20 alkyl group, or a combination thereof, for example, but not limited to, hydrogen or a substituted or unsubstituted C1 to C10 alkyl group, for example, a substituted or unsubstituted C1 to C5 alkyl group.

[0095] R a and R b are each independently deuterium, a hydroxy group, -SCH3, a substituted or unsubstituted C1 to C20 alkyl group, or a combination thereof, for example, -SCH3, a substituted or unsubstituted C1 to C10 alkyl group, or a combination thereof, for example, but not limited to, -SCH3, a substituted or unsubstituted C1 to C5 alkyl group, or a combination thereof.

[0096] The na and nb are each independently one of integers from 0 to 5, for example, one of integers from 0 to 4, for example, one of integers from 0 to 3, but are not limited thereto.

[0097] For example, the radical initiator is represented by one or more of the following formulas 4 to 10:

[0098] [ka] ...chemical formula 4

[0099] [ka] ...chemical formula 5

[0100] [ka] ...chemical formula 6

[0101] [ka] ...chemical formula 7

[0102] [ka] ...chemical formula 8

[0103] [ka] ...chemical formula 9

[0104] [ka] ...chemical formula 10

[0105] The polymer may have a weight-average molecular weight of 1,000 g / mol to 300,000 g / mol, for example, about 3,000 g / mol to 200,000 g / mol, for example, 3,000 g / mol to 100,000 g / mol, for example, 3,000 g / mol to 90,000 g / mol, for example, 3,000 g / mol to 70,000 g / mol, for example, 3,000 g / mol to 70,000 g / mol, for example, 3,000 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 this range, the carbon content and solubility in a solvent of a resist underlayer film composition containing the polymer can be adjusted and optimized.

[0106] The polymer is included 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 is included in an amount of 10 wt % to 50 wt %, for example, 20 wt % to 50 wt %, for example, 20 wt % to 30 wt %, based on the total weight of the composition for a resist underlayer film, but is not limited thereto. By including the polymer in the composition in this range, the thickness, surface roughness, and level of planarization of the resist underlayer film can be adjusted.

[0107] The radical initiator is included in an amount of 0.01 wt % to 30 wt % based on the total weight of the composition for a resist underlayer film. More specifically, the radical initiator is included in an amount of 0.1 wt % to 30.0 wt %, for example, 1.0 wt % to 30.0 wt %, for example, 5.0 wt % to 30.0 wt %, for example, 5.0 wt % to 25.0 wt %, for example, 8.0 wt % to 25.0 wt %, for example, 10.0 wt % to 25.0 wt %, based on the total weight of the composition for a resist underlayer film, but is not limited thereto. By including the radical initiator in the composition in this range, the thickness, surface roughness, chemical resistance, and planarization degree of the resist underlayer film can be adjusted.

[0108] The resist underlayer film composition according to an embodiment may include a solvent. The solvent is not particularly limited as long as it has sufficient solubility and / or dispersibility for the polymer according to an embodiment and the radical initiator, 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, cyclohexanone, ethyl lactate, gamma-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, methylpyrrolidone, methylpyrrolidinone, methyl 2-hydroxyisobutyrate, acetylacetone, ethyl 3-ethoxypropionate, or a combination thereof.

[0109] In addition to the polymer, radical initiator, and solvent, the composition for a resist underlayer film according to an embodiment may further include 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.

[0110] The resist underlayer film composition according to another embodiment may further include additives including a surfactant, a thermal acid generator, a photoacid generator, a plasticizer, or a combination thereof.

[0111] The surfactant may be used to improve coating defects that occur due to an increase in solid content during the formation of the resist underlayer film, and examples of the surfactant include, but are not limited to, alkylbenzene sulfonate, alkylpyridinium salt, polyethylene glycol, and quaternary ammonium salt.

[0112] 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.

[0113] 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, adipates, phosphates, trimellitates, and citrates, as well as polyether, polyester, and polyacetal compounds.

[0114] The additive may be, for example, a compound containing tin (Sn), and by adding the compound containing tin, it is possible to provide a resist underlayer film having improved adhesive strength to the resist. The additive may be represented by, for example, any one of the following chemical formulas X-1 to X-4.

[0115] [ka] ...Chemical formula X-1

[0116] [ka] ...Chemical formula X-2

[0117] [ka] ...Chemical formula X-3

[0118] [ka] ...Chemical formula X-4

[0119] The additive is 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 this range, the solubility of the composition for a resist underlayer film can be improved without changing the optical properties of the composition.

[0120] According to yet another embodiment, there is provided a resist underlayer film prepared using the composition for a resist underlayer film described above. The resist underlayer film may be in a form obtained by, for example, coating the composition for a resist underlayer film on a substrate and then curing it through a heat treatment process.

[0121] A method for forming a pattern using the above-mentioned composition for a resist underlayer film will be described below with reference to Figures 1 to 6. Figures 1 to 6 are cross-sectional views illustrating the method for forming a pattern using the composition for a resist underlayer film according to the present invention.

[0122] Referring to FIG. 1, 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 semiconductor substrate 100. The following description will be limited to the case where the object to be etched is the thin film 102. The surface of the thin film 102 is 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.

[0123] Next, the above-described resist underlayer film composition is coated on the surface of the cleaned thin film 102 by spin coating.

[0124] Thereafter, drying and baking processes are performed to form a resist underlayer film 104 on the thin film. The baking process is performed at 100° C. to 500° C., for example, 100° C. to 300° C. A more specific description of the composition for the resist underlayer film has been given above in detail, so it will be omitted to avoid duplication.

[0125] 2, a photoresist is coated on the resist underlayer film 104 to form a photoresist film 106. In one embodiment, the photoresist composition that forms the photoresist film 106 may include, but is not limited to, an organometallic compound containing Sn, a solvent, etc.

[0126] 3, the photoresist film 106 is selectively exposed. To illustrate the exposure process for exposing the photoresist film 106, an exposure mask having a predetermined pattern formed thereon is placed on a mask stage of an exposure tool, and an exposure mask 110 is aligned over the photoresist film 106. Next, light is irradiated onto the mask 110, so that predetermined portions of the photoresist film 106 formed on the substrate 100 selectively react with the light transmitted through the exposure mask.

[0127] Examples of light that can be used in the exposure process include short wavelength light such as activation irradiation 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 EUV (Extreme ultraviolet) having a wavelength of 13.5 nm, which corresponds to extreme ultraviolet light.

[0128] The exposed regions 106b of the photoresist film 106 have a different solubility from the unexposed regions 106a of the photoresist film 106 due to the formation of a polymer through a crosslinking reaction such as condensation between organometallic compounds.

[0129] Next, a second baking step is performed on the substrate 100. The second baking step can be performed at a temperature of about 90° C. to about 200° C. By performing the second baking step, the exposed region 106b of the photoresist film 106 becomes less soluble in a developer.

[0130] Referring to FIG. 4, the photoresist film 106a corresponding to the unexposed region is dissolved and removed using an organic solvent developer such as 2-heptanone, and the photoresist film 106b remaining after development forms a photoresist pattern 108.

[0131] As described above, the developer used in the pattern formation method according to an embodiment may be an organic solvent. Examples of the organic solvent used in the pattern formation method according to an embodiment include ketones such as methyl ethyl ketone, acetone, cyclohexanone, and 2-heptanone, alcohols such as 4-methyl-2-propanol, 1-butanol, isopropanol, 1-propanol, and methanol, esters such as propylene glycol monomethyl ether acetate, ethyl acetate, ethyl lactate, n-butyl acetate, and butyrolactone, aromatic compounds such as benzene, xylene, and toluene, and combinations thereof.

[0132] However, the photoresist pattern according to an embodiment is not necessarily limited to a negative tone image, and may be formed to have a positive tone image. In this case, developers that can be used to form a positive tone image include quaternary ammonium hydroxide compositions such as tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, or combinations thereof.

[0133] As described above, the photoresist pattern 108 formed by exposure to light having a wavelength such as i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), or ArF excimer laser (wavelength 193 nm), as well as high-energy light such as EUV (Extreme UltraViolet; wavelength 13.5 nm) or E-Beam (electron beam), may have a thickness of 5 nm to 100 nm. For example, the photoresist pattern 108 may have a width of 5 nm to 90 nm, 5 nm to 80 nm, 5 nm to 70 nm, 5 nm to 60 nm, 5 nm to 50 nm, 5 nm to 40 nm, 5 nm to 30 nm, 5 nm to 20 nm, or 5 nm to 10 nm.

[0134] On the other hand, the photoresist pattern 108 can have a half-pitch of about 50 nm or less, e.g., 40 nm or less, e.g., 30 nm or less, e.g., 20 nm or less, e.g., 10 nm or less, and a pitch with a line width roughness of about 5 nm or less, about 3 nm or less, about 2 nm or less, or about 1 nm or less.

[0135] Next, the resist underlayer film 104 is etched using the photoresist pattern 108 as an etching mask, to form an organic film pattern 112 as shown in FIG.

[0136] The formed organic layer pattern 112 may also have a width corresponding to the photoresist pattern 108. The etching may be performed 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 an embodiment has a high etching rate, allowing for a smooth etching process to be performed within a short period of time.

[0137] 6, the photoresist pattern 108 is used as an etching mask to etch the exposed thin film 102. As a result, the thin film is formed into a thin film pattern 114.

[0138] The thin film pattern 114 formed by the previous exposure process using a short wavelength light source such as an activation irradiation i-line (wavelength 365 nm), a KrF excimer laser (wavelength 248 nm), or an ArF excimer laser (wavelength 193 nm) can 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 can have a width of 20 nm or less.

[0139] 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 present invention is not technically limited by the following examples. [Example]

[0140] Polymer synthesis Synthesis Example 1 A 500ml three-neck round-bottom flask was charged with 24.9g of 1,3-diallyl-5-(2-hydroxyethyl)isocyanurate, 7.4g of mercaptoethanol, 0.7g of AIBN (azobisisobutyronitrile), and 48g of N,N-dimethylformamide (DMF), and a condenser was connected. The reaction was allowed to proceed at 80°C for 16 hours, after which the reaction solution was cooled to room temperature. The reaction solution was stirred in a 1L wide-mouth bottle containing 800g of water, and the water was added dropwise to form a gum, which was then dissolved in 80g of tetrahydrofuran (THF). The dissolved resin solution was precipitated using toluene to remove monomolecular and small molecules. Finally, a polymer consisting of the structural unit represented by the following chemical formula 1-1 was obtained. (Weight average molecular weight (Mw)=10,500g / mol)

[0141] [ka] ...Chemical formula 1-1

[0142] Synthesis Example 2 A 500ml three-neck round-bottom flask was charged with 24.9g of 1,3,5-triallyl-1,3,5-triazinane-2,4,6-trione, 7.4g of mercaptoethanol, 0.7g of AIBN (azobisisobutyronitrile), and 48g of N,N-dimethylformamide (DMF), and a condenser was connected. The reaction was allowed to proceed at 80°C for 16 hours, after which the reaction solution was cooled to room temperature. The reaction solution was stirred in a 1L wide-mouth bottle containing 800g of water, and the water was added dropwise to form a gum, which was then dissolved in 80g of THF. The dissolved resin solution was precipitated using toluene to remove monomolecular and small molecules. Finally, a polymer consisting of the structural unit represented by the following chemical formula 1-2 was obtained. (Weight average molecular weight (Mw)=8,000g / mol)

[0143] [ka] ...Chemical formula 1-2

[0144] Production of a composition for a resist underlayer film Examples 1 to 5 and Comparative Example 1 As shown in the composition in Table 1 below, 1.2 g of the polymer obtained in the synthesis example above and the radical initiators represented by the following chemical formulas 4 to 9 and chemical formula X in a ratio of 100:40, 0.4 g of PD1174 (crosslinking agent) and 0.02 g of pyridinium para-toluenesulfonate (PPTS) were mixed and completely dissolved in propylene glycol monomethyl ether to a solid content of 3%, and then diluted with an additional solvent to prepare a resist underlayer film composition according to each example.

[0145] [Table 1]

[0146]

change

[0147]

change

[0148]

change

[0149]

change

[0150]

change

[0151] Comparative Example 2 1.2 g of the polymer represented by Chemical Formula 1-2 obtained in Synthesis Example 2, 0.4 g of PD1174 (crosslinking agent), and 0.02 g of pyridinium para-toluenesulfonate (PPTS) were mixed and completely dissolved in propylene glycol monomethyl ether to a solid content of 3%, and then diluted with an additional solvent to prepare a composition for a resist underlayer film.

[0152] Evaluation 1: Coating uniformity evaluation 2 ml of each of the compositions obtained in the Examples and Comparative Examples was applied to an 8-inch wafer, and spin-coated at a main spin speed of 1,500 rpm for 20 seconds using an auto track (TEL ACT-8), followed by curing at 205°C for 60 seconds to form a thin film with a thickness of 50 Å.

[0153] The thickness was measured at 51 points on the horizontal axis, and the difference between the maximum and minimum thickness values ​​was compared to evaluate the coating uniformity using the following calculation formula 1. The smaller the coating uniformity value, the better the coating uniformity. Specifically, a coating uniformity of less than 2 Å was rated as "excellent," 2 Å to less than 5 Å was rated as "fair," and 5 Å or more was rated as "poor." The results are shown in Table 2 below.

[0154] [Formula 1] Coating uniformity (Å) = Maximum - minimum thickness measured at 51 points within the wafer

[0155] [Table 2]

[0156] Referring to Table 2, it can be seen that the coating uniformity of the resist underlayer films formed from the compositions according to the Examples is smaller than that of the films formed from the compositions according to the Comparative Examples, and that the compositions according to the Examples have better coating uniformity of the resist underlayer films formed from them than the compositions according to the Comparative Examples.

[0157] Evaluation 2: Chemical resistance evaluation 2 ml of each resist underlayer film composition prepared in the Examples and Comparative Examples was applied to a 4-inch wafer and spin-coated at 1,500 rpm for 20 seconds using a spin coater (Mikasa). The film was then cured at 210°C for 90 seconds, and the thickness of the resulting thin film was measured using a K-MAC thin film thickness meter. The thin film was then immersed in a mixed solvent (70 wt% propylene glycol monomethyl ether + 30 wt% propylene glycol monomethyl ether acetate) for 1 minute, removed, and the thickness of the thin film was measured. The chemical resistance of the underlayer film was evaluated based on the thickness reduction rate measured before and after application, using Equation 2 below. The smaller the thickness reduction rate, the better the chemical resistance. The results are shown in Table 3 below.

[0158] [Formula 2] Lower layer film thickness reduction rate (%) = {(thickness of thin film before loading - thickness of thin film after loading) / thickness of thin film before loading} x 100

[0159] [Table 3]

[0160] Referring to Table 2, it can be seen that the chemical resistance of the resist underlayer films formed from the compositions according to the examples is superior to that of the comparative examples.

[0161] 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 and variations should not be understood separately from the technical spirit and perspective of the present invention, and the modified embodiments should be included within the scope of the claims of the present invention. [Explanation of symbols]

[0162] 100: substrate, 102: thin film 104: resist underlayer film, 106: photoresist film 106a: non-exposed area, 106b: 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 including a structural unit represented by the following chemical formula 1, a structural unit represented by the following chemical formula 2, or a combination thereof; a radical initiator having a bond dissociation energy (BDE) of 0 to 60 kcal / mol; and a solvent: 【Chemical 1】 ...Chemical formula 1 【Chemistry 2】 ...Chemical formula 2 In the above Chemical Formula 1 and Chemical Formula 2, A is a heterocyclic group containing a nitrogen atom in the ring, L １ ~L ６ are each independently 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 C3 to C20 heteroarylene group, or a combination thereof; X １ ~X ５ are each independently a single bond, —O—, —S—, —S(═O)—, or —S(═O) ２ -, -C(=O)-, -(CO)O-, -O(CO)O-, -NR ａ - (where R ａ is hydrogen, deuterium, or a C1-C10 alkyl group), or a combination thereof; Y １ ~Y ３ are each independently a hydroxy group, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, a substituted or unsubstituted C2 to C10 alkynyl group, a substituted or unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted C2 to C10 heteroalkenyl group, a substituted or unsubstituted C2 to C10 heteroalkynyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C3 to C20 heteroaryl group, or a combination thereof; * indicates the binding site.

2. 2. The resist underlayer film composition according to claim 1, wherein A is represented by one or more of the following chemical formulas A-1 to A-4: 【Chemistry 3】 ...Chemical formula A-1 【Chemistry 4】 ...Chemical formula A-2 【Chemistry 5】 ...Chemical formula A-3 【Chemistry 6】 ...Chemical formula A-4 In the chemical formulas A-1 to A-4, The R ｘ is hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C2-C10 alkenyl group, or a substituted or unsubstituted C2-C10 alkynyl group; * indicates the binding site.

3. Said L １ ~L ６ are each independently a single bond, a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C1-C10 heteroalkylene group, or a combination thereof; X １ ~X ５ each independently represents a single bond, —O—, —S—, —C(═O)—, —(CO)O—, —O(CO)O—, or a combination thereof, Y １ ~Y ３ are each independently a hydroxy group, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, a substituted or unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted C2 to C10 heteroalkenyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a combination thereof.

4. The composition for a resist underlayer film according to claim 1, wherein the radical initiator is represented by any one of the following Chemical Formulas 3-1 to 3-4: 【Chemistry 7】 ...Chemical formula 3-1 【Chemistry 8】 ...Chemical formula 3-2 【Chemistry 9】 ...Chemical formula 3-3 【Chemistry 10】 ...Chemical formula 3-4 In Chemical Formula 3-1 to Chemical Formula 3-4, R １ ~R ５ are each independently a hydroxy group, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a combination thereof; R ６ ~R ９ are each independently hydrogen, deuterium, a hydroxy group, a substituted or unsubstituted C1 to C20 alkyl group, or a combination thereof; R ａ and R ｂ are each independently a deuterium atom, a hydroxy group, or —SCH ３ , a substituted or unsubstituted C1 to C20 alkyl group, or a combination thereof; na and nb are each independently an integer from 0 to 5;

5. The composition for a resist underlayer film according to claim 1, wherein the radical initiator is represented by any one or more of the following formulas 4 to 10: 【Chemistry 11】 ...Chemical formula 4 【Chemistry 12】 ...Chemical formula 5 【Chemistry 13】 ...Chemical formula 6 【Chemistry 14】 ...Chemical formula 7 【Chemistry 15】 ...Chemical formula 8 【Chemistry 16】 ...Chemical formula 9 【Chemistry 17】 ...Chemical formula 10

6. 2. The composition for a resist underlayer film according to claim 1, wherein Chemical Formula 1 is represented by the following Chemical Formula 1-1 or Chemical Formula 1-2, and Chemical Formula 2 is represented by any one of the following Chemical Formulas 2-1 to 2-3: 【Chemistry 18】 ...Chemical formula 1-1 【Chemistry 19】 ...Chemical formula 1-2 【Chemistry 20】 ...Chemical formula 2-1 【Chemical 21】 ...Chemical formula 2-2 【Chemical 22】 ...Chemical formula 2-3

7. 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.

8. 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.

9. 2. The composition for a resist underlayer film according to claim 1, wherein the radical initiator is contained in an amount of 0.01% by weight to 30% 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; forming a resist underlayer film by applying the composition for a resist underlayer film according to any one of claims 1 to 11 onto the film to be etched; forming a photoresist pattern on the resist underlayer film; gradually etching the resist underlayer film and the etching target film using the photoresist pattern as an etching mask; A pattern forming method comprising:

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