Resist underlayer film composition and method of forming patterns using the same

Abstract

To provide a resist underlayer film composition capable of forming a resist underlayer film that has improved crosslinking characteristics and coating uniformity, as well as an excellent etching rate and pattern forming property, in which the resist pattern collapse does not occur even during a fine patterning process.SOLUTION: The present invention relates to a resist underlayer film composition that includes a polymer including a structural unit represented by chemical formula 1, and a solvent, as well as a method of forming a pattern using the resist underlayer film composition. The definitions of the chemical formula 1 are as described in the specification.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Recently, the semiconductor industry has been evolving from patterns of hundreds of nanometers to ultra-fine technology with patterns of several to tens of nanometers. Effective lithographic techniques are essential to realize such ultra-fine technology.

[0003] Lithographic techniques involve coating a semiconductor substrate such as a silicon wafer with a photoresist film to form a thin film, exposing the thin film to activating radiation such as ultraviolet light through a mask pattern on which a device pattern is drawn, and developing the film. The resulting photoresist pattern is then used as a protective film to etch the substrate, thereby forming a fine pattern on the substrate surface that corresponds to the pattern.

[0004] As semiconductor patterns become finer, the thickness of the photoresist layer is required to become thinner, and therefore the thickness of the resist underlayer film is also required to become thinner. The resist underlayer film must not collapse the photoresist pattern even at a thin thickness, must have good adhesion to the photoresist, and must be formed with a uniform film thickness. In addition, the resist underlayer film must have a high refractive index and a low absorption coefficient for the light used in photolithography, and must have an etching speed faster than the photoresist layer. Summary of the Invention [Problem to be solved by the invention]

[0005] The composition for a resist underlayer film according to an embodiment provides a resist underlayer film that improves adhesion between the resist and the resist underlayer film and does not cause pattern collapse of the resist even during fine patterning processes. The composition for a resist underlayer film according to an embodiment provides a resist underlayer film having improved crosslinking properties, coating uniformity, and excellent etching rate and pattern formability. Another embodiment provides a method for forming a pattern using the composition for a resist underlayer film. [Means for solving the problem]

[0006] The composition for a resist underlayer film according to an embodiment includes a polymer having a structural unit represented by the following Formula 1, and a solvent: [ka] In the above Chemical Formula 1, L 1 ~L 4 are each independently a substituted or unsubstituted C1 to C20 alkyl or alkylene group, L 5 ~L 8 are each independently a single bond, a substituted or unsubstituted C1 to C20 alkyl group or alkylene group, a substituted or unsubstituted C2 to C20 alkenyl group or alkenylene group, a substituted or unsubstituted C2 to C20 alkynyl group or alkynylene group, a substituted or unsubstituted C3 to C20 cycloalkyl group or cycloalkylene group, a substituted or unsubstituted C6 to C30 aryl group or arylene group, or a combination thereof; M 1 ~M 8 are each independently a single bond, -C(=O)-, -OC(=O)-, or a combination thereof; x 1 ~x 4 are each independently 0 or 1, and x 1 ~x 4 Two or more of are 1, y 1 ~y 4 are each independently 0 or 1, z 1 ~z 4 are each independently 0 or 1, R 1 and R2 are each independently hydrogen, deuterium, a hydroxy group, a substituted or unsubstituted C1-C10 alkoxy 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, or a combination thereof; * indicates the connection point with other structural units.

[0007] L of the above Chemical Formula 1 1 ~L 4 are each independently a substituted or unsubstituted C1 to C10 alkyl or alkylene group, L 5 ~L 8 each independently represents a single bond, a substituted or unsubstituted C1 to C10 alkyl group or alkylene group, a substituted or unsubstituted C2 to C10 alkenyl group or alkenylene group, a substituted or unsubstituted C2 to C10 alkynyl group or alkynylene group, or a combination thereof; M 1 ~M 8 are each independently a single bond, -C(=O)-, or a combination thereof; x 1 ~x 4 Two of them are 1 and the other two are 0, R 1 and R 2 are each independently hydrogen, deuterium, a hydroxyl group, a substituted or unsubstituted C1 to C10 alkoxy group, a substituted or unsubstituted C1 to C10 alkyl group, or a combination thereof.

[0008] L5 to L8 in the above Chemical Formula 1 are each independently a single bond, a substituted or unsubstituted C1 to C10 alkyl or alkylene group, or a combination thereof; M 1 ~M 8 are each independently a single bond, -C(=O)-, or a combination thereof; R1 and R 2 is hydrogen. In the above Chemical Formula 1, x 1 and x 4 is 1, and x 2 and x 3 is 0.

[0009] The formula 1 is represented by at least one of the following formulas 1-1 and 1-2: [ka] [ka] In the above Chemical Formula 1-1 and Chemical Formula 1-2, R 11 , R 12 , R 21 , and R 22 are each independently hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group; R 13 , R 14 , R 23 , and R 24 are each independently hydrogen, deuterium, a hydroxyl group, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 alkoxy group, or a combination thereof; n 1 and n 2 are each independently an integer from 1 to 10, * indicates a connection point.

[0010] The weight average molecular weight of the polymer is from 1,000 g / mol to 300,000 g / mol. 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 resist underlayer film.

[0011] The resist underlayer film composition further includes one or more polymers selected from an acrylic resin, an epoxy resin, a novolac resin, a glycoluril resin, and a melamine resin. The resist underlayer film composition further includes an additive that is a surfactant, a thermal acid generator, a photoacid generator, a plasticizer, or a combination thereof.

[0012] According to another embodiment, there is provided a method for forming a pattern, the method including: forming a film to be etched on a substrate; applying a resist underlayer film composition according to an embodiment onto 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.

[0013] The composition for a resist underlayer film according to an embodiment can provide a resist underlayer film that has improved adhesion between the resist and the resist underlayer film and does not cause pattern collapse of the resist even in a fine patterning process. In addition, the composition for a resist underlayer film according to an embodiment may provide a resist underlayer film having improved crosslinking properties and coating uniformity, and excellent etching rate and pattern formability. [Brief description of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view illustrating a method for forming a pattern using a composition for a resist underlayer film according to an embodiment. [Diagram 2] 1 is a cross-sectional view illustrating a method for forming a pattern using a composition for a resist underlayer film according to an embodiment. [Diagram 3] 1 is a cross-sectional view illustrating a method for forming a pattern using a composition for a resist underlayer film according to an embodiment. [Figure 4] 1 is a cross-sectional view illustrating a method for forming a pattern using a composition for a resist underlayer film according to an embodiment. [Diagram 5] 1 is a cross-sectional view illustrating a method for forming a pattern using a composition for a resist underlayer film according to an embodiment. [Figure 6]1 is a cross-sectional view illustrating a method for forming a pattern using a composition for a resist underlayer film according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to exemplary embodiments so that those skilled in the art can easily practice 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.

[0016] In the drawings, the thickness is exaggerated to clearly show multiple layers and regions, and similar parts are given the same drawing reference numbers throughout the specification. When a part such as a layer, film, region, or plate is "on" another part, this includes not only when it is "directly on" the other part, but also when there is another part between them. Conversely, when a part is "directly on" another part, it means that there is no other part between them.

[0017] Hereinafter, unless otherwise defined in the present specification, "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 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 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.

[0018] 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, carbamoyl 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, or C2-C30 heterocyclic groups may be fused to form a ring.

[0019] In this specification, unless otherwise defined, the term "hetero" means containing 1 to 3 heteroatoms selected from N, O, S, Se and P. 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 linked by single bonds 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 which share adjacent pairs of carbon atoms) functionalities.

[0020] In this specification, the term "heterocyclic group" refers to a concept that includes heteroaryl groups, and in addition, means that the heterocyclic group contains at least one heteroatom selected from N, O, S, P, and Si in place of carbon (C) in a ring compound such as an aryl group, a cycloalkyl group, a fused ring thereof, or a combination thereof. When the heterocyclic group is a fused ring, the entire heterocyclic group or each ring may contain one or more heteroatoms.

[0021] More specifically, the substituted or unsubstituted aryl group and / or the substituted or unsubstituted heterocyclic group are 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 aryl ... a 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 group, a substituted or unsubstituted pyrazinyl group, 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 benzothiazinyl group, a substituted or unsubstituted acridinyl group, a substituted or an 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, or a combination thereof or a fused form of a combination thereof, but is not limited thereto. In this specification, unless otherwise specified, "combination" means mixing or copolymerization.

[0022] In addition, in this specification, the term "polymer" can include both an oligomer and a polymer. In this specification, unless otherwise specified, 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) (Shodex LF-804 column and Shodex polystyrene standard). Also, in this specification, unless otherwise defined, "*" indicates a structural unit of a compound or a linking point of a moiety of a compound.

[0023] In the semiconductor industry, there is a continuing demand to reduce the size of chips. To meet this trend, the line width of the resist patterned by lithography technology must be reduced to the level of several tens of nanometers, and the pattern thus formed is then transferred to the underlying material by an etching process on the underlying substrate. However, as the resist pattern size becomes smaller, the aspect ratio of the resist that can withstand the line width becomes limited, and as a result, the resist may not have sufficient resistance in the etching step. Therefore, a resist underlayer film has been used to compensate for this when a thin resist material is used, when the substrate to be etched is thick, or when a deep pattern is required.

[0024] The resist underlayer film is required to become thinner as the resist becomes thinner, and the photoresist pattern must not collapse even when the resist underlayer film is thin. For this reason, the resist underlayer film must have excellent adhesion to the photoresist. In addition, when forming a thin resist underlayer film, the crosslinking property and coating uniformity of the composition for the resist underlayer film must be improved.

[0025] The composition for the underlayer film according to one embodiment includes a polymer having a structural unit represented by the following Formula 1, and a solvent: [ka]

[0026] In the above Chemical Formula 1, L 1 ~L 4 are each independently a substituted or unsubstituted C1 to C20 alkyl or alkylene group, L 5 ~L 8 are each independently a single bond, a substituted or unsubstituted C1 to C20 alkyl group or alkylene group, a substituted or unsubstituted C2 to C20 alkenyl group or alkenylene group, a substituted or unsubstituted C2 to C20 alkynyl group or alkynylene group, a substituted or unsubstituted C3 to C20 cycloalkyl group or cycloalkylene group, a substituted or unsubstituted C6 to C30 aryl group or arylene group, or a combination thereof; M 1 ~M 8 are each independently a single bond, -C(=O)-, -OC(=O)-, or a combination thereof; x 1 ~x 4 are each independently 0 or 1, and x 1 ~x 4 Two or more of are 1, y 1 ~y 4 are each independently 0 or 1, z 1 ~z 4 are each independently 0 or 1, R 1 and R 2 are each independently hydrogen, deuterium, a hydroxy group, a substituted or unsubstituted C1-C10 alkoxy 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, or a combination thereof; * indicates the connection point with other structural units.

[0027] The polymer includes a glycoluril structure formed of two cyclic urea groups fused together by a chain connecting the same two carbons, as shown in the structural unit represented by Chemical Formula 1. The glycoluril structure includes a carbonyl group (-C(=O)-) and two nitrogen atoms connected thereto that contain non-shared electron pairs, resulting in an interpolymer sp 2 -sp 2 As a result, the composition for an underlayer film containing the polymer has high electron density, and the density of the thin film produced therefrom is improved, and a film with a dense structure can be realized in the form of an ultra-thin film. In addition, the composition can have improved light absorption efficiency upon exposure to light.

[0028] In addition, the crosslinking properties and coating uniformity of the composition for resist underlayer film including the polymer can be adjusted by the substituent or linking group linked to the nitrogen (N) of glycoluril in the structural unit. For example, when the linking group linked to N of glycoluril includes a functional group having a non-shared electron pair such as -O- or -C(=O)-, or includes a hydrophilic substituent such as a hydroxyl group or an alkoxy group, the number of crosslinkable sites of the polymer increases. Therefore, the resist underlayer film formed from the composition including the polymer having many crosslinkable sites can have a more dense structure. Meanwhile, the linking group linked to N of glycoluril can include a hydrophobic group such as an alkylene group, an alkenylene group, or an alkynylene group, and a composition including many such hydrophobic groups can improve the coating properties and increase the etching rate. Therefore, the crosslinking properties and / or coating uniformity of the composition including the polymer can be optimized by adjusting the substituent or linking group in the structural unit represented by Chemical Formula 1. For the same reason, the etching rate and pattern formability of a resist underlayer film formed from the composition can also be improved.

[0029] In the above Chemical Formula 1, x 1 ~x 4 When x is 1, the four ends extending from the glycoluril are connected to other structural units, for example, 1 ~x 4 When at least two of the x are 1, the x can be bonded to two or more other structural units. Therefore, the resist underlayer film formed from the composition containing the polymer can have a denser structure. 1 ~x 4 When two or more of the above are 1, the coating uniformity of the composition containing the polymer is further improved.

[0030] In the above Chemical Formula 1, L 1 ~L 4are each independently a substituted or unsubstituted C1-C10 alkyl group or alkylene group, for example, a substituted or unsubstituted C1-C5 alkyl group or alkylene group, for example, a substituted or unsubstituted methyl group or methylene group, or a substituted or unsubstituted ethyl group or ethylene group, but are not limited thereto. By including such a linking group, the polymer including the structural unit can have excellent fluidity and can have increased solubility in a solvent.

[0031] Said L 5 ~L 8 are each independently a single bond, a substituted or unsubstituted C1 to C10 alkyl group or alkylene group, a substituted or unsubstituted C2 to C10 alkenyl group or alkenylene group, a substituted or unsubstituted C2 to C10 alkynyl group or alkynylene group, or a combination thereof, for example, but not limited to, a single bond, a substituted or unsubstituted C1 to C10 alkyl group or alkylene group, or a combination thereof. 5 ~L 8 x 1 ~x 4 When each is 0, it can exist as a monovalent group, and x 1 ~x 4 When each is 1, it can exist as a divalent group.

[0032] In the above formula 1, R 1 and R 2 are each independently hydrogen, deuterium, a hydroxy group, a substituted or unsubstituted C1 to C10 alkoxy group, a substituted or unsubstituted C1 to C10 alkyl group, or a combination thereof, for example, but not limited to, hydrogen or deuterium.

[0033] In one embodiment, L in Formula 1 1 ~L 4 are each independently a substituted or unsubstituted methyl group or methylene group; L 5 ~L 8are each independently a single bond, a substituted or unsubstituted C1 to C10 alkyl or alkylene group, or a combination thereof; M 1 ~M 8 are each independently a single bond, -C(=O)-, or a combination thereof; R 1 and R 2 is hydrogen, but is not limited to these.

[0034] In the above Chemical Formula 1, x 1 ~x 4 are each independently 0 or 1, and x 1 ~x 4 Two or more of the following are 1, or three or more are 1, e.g., x 1 ~x 4 Two of them are 1, for example x 1 and x 4 is 1 or x 2 and x 3 can be 0, for example x 1 and x 2 is 1, and x 3 and x 4 can be 0, for example, x1 and x 3 is 1, and x 2 and x 4 can be 0. For example, x 1 and x 4 is 1, and x 2 and x 3 is 0, but is not limited to these.

[0035] As an example, the formula 1 may be represented by one or more of the following formulas 1-1 and 1-2: [ka] [ka]

[0036] In the above Chemical Formula 1-1 and Chemical Formula 1-2, R 11 , R 12 , R21 , and R 22 are each independently hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group; R 13 , R 14 , R 23 , and R 24 are each independently hydrogen, deuterium, a hydroxyl group, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 alkoxy group, or a combination thereof; 1 and n 2 are each independently an integer from 1 to 10.

[0037] In one embodiment, the R 11 , R 12 , R 21 , and R 22 are each independently a substituted or unsubstituted C1 to C5 alkyl group, such as, but not limited to, a substituted or unsubstituted methyl group, or a substituted or unsubstituted butyl group. In one embodiment, the R 13 , R 14 , R 23 , and R 24 are each independently hydrogen, deuterium, a hydroxy group, or a substituted or unsubstituted C1 to C5 alkyl group, for example, but not limited to, hydrogen, deuterium, or a hydroxy group. In one embodiment, n 1 and n 2 each independently represents an integer of 1 to 5, for example, an integer of 1 to 3, for example, an integer of 1 or 2, but is not limited thereto.

[0038] The polymer has a weight average molecular weight of 1,000g / mol to 300,000g / mol, for example, about 3,000g / mol to 200,000g / mol, for example, 3,000g / mol to 100,000g / mol, for example, 3,000g / mol to 90,000g / mol, for example, 3,000g / mol to 70,000g / mol, for example, 3,000g / mol to 70,000g / mol, for example, 3,000g / mol to 50,000g / mol, for example, 5,000g / mol to 50,000g / mol, for example, 5,000g / mol to 30,000g / mol, but is not limited thereto. By having a weight average molecular weight in the above range, the carbon content and solubility in a solvent of the composition for resist underlayer film containing the polymer can be adjusted and optimized.

[0039] In one embodiment, the polymer may be included in an amount of 0.1 wt% to 50 wt% based on the total weight of the composition for resist underlayer film. More specifically, the polymer may be included in an amount of 10 wt% to 50 wt%, for example, 20 wt% to 50 wt%, for example, 20 wt% to 40 wt%, for example, 20 wt% to 30 wt%, based on the total weight of the composition for resist underlayer film, but is not limited thereto. By including the polymer in the composition in the above range, the thickness and coating uniformity of the resist underlayer film can be adjusted.

[0040] The composition for the resist underlayer film according to an embodiment may include a solvent. The solvent may be any solvent having sufficient solubility and / or dispersibility for the polymer and compound according to an embodiment, and may include, but is not limited to, for example, propylene glycol, propylene glycol diacetate, methoxypropane diol, diethylene glycol, diethylene glycol butyl ether, tri(ethylene glycol) monomethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, ethyl lactate, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, methylpyrrolidone, methylpyrrolidinone, methyl 2-hydroxyisobutyrate, acetylacetone, ethyl 3-ethoxypropionate, or a combination thereof.

[0041] The composition for a resist underlayer film according to an embodiment may further include, in addition to the polymer, compound, and 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. The composition for a resist underlayer film according to another embodiment may further include additives including a surfactant, a thermal acid generator, a plasticizer, or a combination thereof.

[0042] The surfactant may be used to improve coating defects caused by an increase in solid content during the formation of a resist underlayer film, and examples of the surfactant include, but are not limited to, alkylbenzenesulfonate, alkylpyridinium salt, polyethylene glycol, and quaternary ammonium salt.

[0043] The thermal acid generator may be, for example, an acidic compound such as p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonate, salicylic acid, sulfosalicylic acid, citric acid, benzoic acid, hydroxybenzoic acid, naphthalenecarboxylic acid, or / and an organic sulfonic acid alkyl ester such as benzoin tosylate, 2-nitrobenzyl tosylate, or the like, but is not limited thereto.

[0044] 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, polyether-based, polyester-based, and polyacetal-based compounds.

[0045] The additive may be contained in an amount of 0.001 to 40 parts by weight based on 100 parts by weight of the composition for resist underlayer film. By containing the additive in the above range, the solubility of the composition for resist underlayer film can be improved without changing the optical properties of the composition for resist underlayer film.

[0046] According to 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 coating the composition for a resist underlayer film on a substrate, for example, and then curing the composition through a heat treatment process.

[0047] Hereinafter, a method for forming a pattern using the above-mentioned composition for a resist underlayer film will be described with reference to FIGS. 1 to 6 are cross-sectional views illustrating a pattern forming method using a resist underlayer film composition according to the present invention.

[0048] Referring to FIG. 1, a first etching target is prepared. An example of the first etching target may be a thin film 102 formed on a semiconductor substrate 100. Hereinafter, only the case where the first etching target is the thin film 102 will be described. 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.

[0049] Then, the above-mentioned composition for a resist underlayer film is coated on the surface of the cleaned thin film 102 by spin coating.

[0050] 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, at 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.

[0051] Referring to FIG. 2, a photoresist is coated on the resist underlayer film 104 to form a photoresist film 106 .

[0052] Examples of the photoresist include a Western-style positive photoresist containing a naphthoquinone diazide compound and a novolak resin; a chemically amplified Western-style photoresist containing an acid generator capable of dissociating an acid upon exposure, a compound that decomposes in the presence of an acid to increase its solubility in an alkaline aqueous solution, and an alkali-soluble resin; and a chemically amplified Western-style photoresist containing an acid generator and an alkali-soluble resin having a group that can decompose in the presence of an acid to give a resin that has increased solubility in an alkaline aqueous solution.

[0053] Next, a first baking process is performed to heat the substrate 100 on which the photoresist film 106 is formed. The first baking process can be performed at a temperature of 90°C to 120°C.

[0054] 3, the photoresist film 106 is selectively exposed to light. To explain an exposure process for exposing the photoresist film 106 as an example, an exposure mask having a predetermined pattern formed thereon is positioned on a mask stage of an exposure tool, and an exposure mask 110 is aligned on the photoresist film 106. Then, light is irradiated onto the mask 110, so that a predetermined portion of the photoresist film 106 formed on the substrate 100 selectively reacts with the light transmitted through the exposure mask.

[0055] Examples of light that can be used in the exposure process include short wavelength light such as an activation irradiation conductor i-line having a wavelength of 365 nm, a KrF excimer laser having a wavelength of 248 nm, and an ArF excimer laser having a wavelength of 193 nm, as well as extreme ultraviolet (EUV) having a wavelength of 13.5 nm, which corresponds to extreme light.

[0056] The exposed portion of the photoresist film 106a is relatively hydrophilic compared to the unexposed portion of the photoresist film 106b, and therefore the exposed portion 106a and the unexposed portion 106b of the photoresist film have different solubilities.

[0057] 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 corresponding to the exposed region becomes easily dissolved in a specific solvent.

[0058] Referring to FIG. 4, specifically, the photoresist film 106a corresponding to the exposed region is dissolved and then removed using tetra-methylammonium hydroxide (TMAH) or the like, and the remaining photoresist film 106b after development forms the photoresist pattern 108.

[0059] Next, the resist underlayer film 104 is etched using the photoresist pattern 108 as an etching mask. Through this etching process, an organic film pattern 112 is formed as shown in FIG. The etching can be performed, for example, by dry etching using an etching gas, and the etching gas can be, for example, CHF3, CF4, Cl2, O2, 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, and therefore, a smooth etching process can be performed within a short time.

[0060] 6, the photoresist pattern 108 is applied as an etching mask to etch the exposed thin film 102. As a result, the thin film is formed as a thin film pattern 114. In the previous exposure process, the thin film pattern 114 formed by the exposure process performed using a short wavelength light source such as an activation irradiation conductor i-line (wavelength 365 nm), a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), etc. has a width of several tens to several hundreds of nm, while the thin film pattern 114 formed by the exposure process performed using an EUV light source can have a width of 20 nm or less.

[0061] The present invention will be described in more detail below with reference to examples of synthesis of the above-mentioned polymer and preparation of a composition for a resist underlayer film containing the same. However, the present invention is not technically limited by the following examples.

[0062] Polymer synthesis Synthesis Example 1 In a 500 mL two-neck round bottom flask equipped with a container, 0.5 g of p-toluene sulfonic acid (PTSA), 30 g of 1,3,4,6-Tetrakis(methoxymethyl)glycoluril (TMGU), 3 g of 1,2-ethanediol, and 150 g of 1,4-dioxane are added and reacted at 80°C for 10 hours. After the reaction is completed, the reaction solution is cooled to room temperature. Then, triethylamine is added to the reaction solution to neutralize it, and the solution is purified to finally obtain polymer 1 composed of structural units represented by the following chemical formula 2.

[0063] [ka]

[0064] Synthesis Example 2 Polymer 2 composed of structural units represented by the following formula 3 was obtained in the same manner as in Synthesis Example 1, except that 6 g of succinic acid was used instead of 1,2-ethanediol.

[0065] [ka]

[0066] Synthesis Example 3 Polymer 3 composed of structural units represented by the following chemical formula 4 was obtained in the same manner as in Synthesis Example 1, except that 45 g of 1,3,4,6-tetrakis(butoxymethyl)glycoluril was used instead of 30 g of 1,3,4,6-tetrakis(methoxymethyl)glycoluril (TMGU) and 7.5 g of 2,3-dihydroxysuccinic acid was used instead of 1,2-ethanediol.

[0067] [ka]

[0068] Comparative synthesis example 1 A reaction solution is prepared by adding 20g of 1,3-diallyl-5-(1-hydroxyethyl)-isocyanurate, 6.0g of 1,3-propanedithiol, 1g of azobisisobutyronitrile (AIBN), and 50g of N,N-dimethylformamide to a 250mL four-neck flask, and a condenser is connected. The reaction solution is heated at 50°C for 5 hours to proceed with the reaction, and then cooled to room temperature. The reaction solution is then stirred in a beaker containing 300g of distilled water, and dropped to produce a gum, which is then dissolved in 30g of tetrahydrofuran (THF). The dissolved resin solution is precipitated in toluene to remove monomolecules and low molecular weight compounds, and finally a polymer composed of structural units represented by the following chemical formula 5 (weight average molecular weight (Mw) = 5,500 g / mol) is obtained.

[0069] [ka]

[0070] Comparative synthesis example 2 In a 1L two-necked round flask, 148.6g of 1,3,5-triglycidyl isocyanurate, 60.0g of 2,2'-thiodiacetic acid, 9.1g of benzyltriethyl ammonium chloride, and 350g of N,N-dimethylformamide are added and a condenser is connected. The temperature is raised to 100°C, and the reaction is allowed to proceed for 8 hours, after which the reaction liquid is cooled to room temperature (23°C). The reaction liquid is then transferred to a 1L wide-mouthed bottle, washed three times with hexane, and then washed in sequence with purified water. The resulting gum-like resin is completely dissolved using 80g of THF, and then slowly dripped into 700g of toluene while stirring. Thereafter, the solvent is removed to finally obtain a polymer composed of structural units represented by the following chemical formula 6 (weight average molecular weight (Mw) = 8, 200 g / mol).

[0071] [ka]

[0072] Comparative synthesis example 3 In a 500mL two-neck round bottom flask equipped with a container, 0.5g of p-toluenesulfonic acid (PTSA), 30g of Comparative Synthesis Example 1, 3,4,6-Tetrakis(methoxymethyl)glycoluril (TMGU) 3g, and 150g of Methyl 2-Hydroxyisobutyrate are added and reacted at 80°C for 2 hours. After the reaction is allowed to proceed, the reaction solution is cooled to room temperature. Then, triethylamine is added to the reaction solution to neutralize it, and the solution is purified to finally obtain a polymer (weight average molecular weight (Mw) = 6, 200g / mol) composed of structural units represented by the following chemical formula 7.

[0073] [ka]

[0074] Example 1 0.1 g of the polymer prepared in Synthesis Example 1 and 0.01 g of pyridinium para-toluenesulfonate (PPTS) were completely dissolved in 90 g of propylene glycol monomethyl ether and 5 g of ethyl lactate, and then the mixture was further diluted with a solvent to prepare a composition for a resist underlayer film according to Example 1.

[0075] Example 2 A composition for a resist underlayer film was prepared in the same manner as in Example 1, except that the polymer prepared in Synthesis Example 2 was used instead of the polymer prepared in Synthesis Example 1.

[0076] Example 3 A composition for a resist underlayer film was prepared in the same manner as in Example 1, except that the polymer prepared in Synthesis Example 3 was used instead of the polymer prepared in Synthesis Example 1.

[0077] Comparative Example 1 0.5 g of the polymer prepared in Comparative Synthesis Example 1 was added, and 0.15 g of PD1174 (TCI; crosslinking agent) and 0.01 g of pyridinium para-toluenesulfonate (PPTS) were added, and the mixture was completely dissolved in 90 g of propylene glycol monomethyl ether and 5 g of ethyl lactate, followed by further dilution with a solvent to prepare a composition for a resist underlayer film according to Comparative Example 1.

[0078] Comparative Example 2 A composition for a resist underlayer film was prepared in the same manner as in Comparative Example 1, except that the polymer prepared in Comparative Synthesis Example 2 was used instead of the polymer prepared in Comparative Synthesis Example 1.

[0079] Comparative Example 3 A composition for a resist underlayer film was prepared in the same manner as in Comparative Example 2, except that PD1174 (TCI; crosslinking agent) was not used.

[0080] Comparative Example 4 A composition for a resist underlayer film was prepared in the same manner as in Comparative Example 1, except that the polymer prepared in Comparative Synthesis Example 3 was used instead of the polymer prepared in Comparative Synthesis Example 1.

[0081] Evaluation 1: Coating uniformity evaluation 2 ml of each of the compositions obtained in Examples 1 to 3 and Comparative Examples 1 to 4 was taken and coated on an 8-inch wafer, and then spin-coated at a main spin speed of 1,500 rpm for 20 seconds using an auto track (TEL Corporation ACT-8), and cured at 205°C for 60 seconds to form a thin film with a thickness of 50 Å.

[0082] 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 formula 1. The smaller the coating uniformity value, the better the coating uniformity is. Specifically, coating uniformity of less than 2 Å is rated as "excellent," 2 Å to less than 5 Å is rated as "average," and 5 Å or more is rated as "poor." The results are shown in Table 1 below. [Formula 1] Coating uniformity (Å) = Maximum-minimum thickness measured at 51 points on a wafer

[0083] [Table 1]

[0084] Referring to Table 1, it can be seen that the coating uniformity of the resist underlayer film formed from the composition according to the embodiment is smaller or equal to that of the film formed from the composition according to the comparative example, and the coating uniformity of the resist underlayer film formed from the composition according to the embodiment is better than that of the composition according to the comparative example.

[0085] Evaluation 2: Etching rate evaluation The resist underlayer film compositions according to Examples 1 to 3 and Comparative Examples 1 to 4 were spin-coated on a silicon wafer and heat-treated at 240°C for 120 seconds, and the thickness of the coated thin film was measured. The thin film was then dry-etched for 60 seconds using a N2 / O2 mixed gas, and the thickness of the thin film was measured. The thin film was also dry-etched for 100 seconds using CFx gas, and the thickness of the thin film was measured. The etch rate was calculated from the thin film thickness before and after dry etching and the etching time according to the following formula 2, and the remaining etch rates were converted relatively based on the etch rate of Example 1, and the results are shown in Table 2 below. [Formula 2] Etching rate (Å / s) = (initial base film thickness - thin film thickness after etching) / etching time

[0086] [Table 2]

[0087] Referring to Table 2, it can be seen that the thin films formed from the compositions for resist underlayer films according to the Examples have higher etching rates than the thin films formed from the compositions for resist underlayer films according to the Comparative Examples.

[0088] Evaluation 3: Contact angle evaluation 2 ml of each of the resist underlayer film compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was applied onto a 4-inch wafer, and spin-coated at 1,500 rpm for 20 seconds using a spin coater (Mikasa). After curing at 210°C for 90 seconds to form a thin film, the contact angle was measured when distilled water (DIW) was dropped onto the surface. The smaller the contact angle, the better the adhesion to the resist. The measured contact angles are shown in Table 3 below.

[0089] [Table 3]

[0090] Referring to Table 3, it can be seen that the contact angle of distilled water is lower in the resist underlayer film formed from the composition according to the embodiment, and the adhesion between the resist underlayer film formed from the composition according to the embodiment and the resist is superior to the adhesion between the resist underlayer film formed from the composition according to the comparative example and the resist.

[0091] Evaluation 4: Chemical resistance evaluation 2 ml of each of the resist underlayer film compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was applied onto a 4-inch wafer, and spin-coated at 1,500 rpm for 20 seconds using a spin coater (Mikasa). Then, curing was performed at 210° C. for 90 seconds, and the thickness of the formed thin film was measured using a thin film thickness measuring device (K-MAC). Next, the thin film was immersed in a mixed solvent of ethyl 3-ethoxypropionate (EEP) and ethyl lactate (EL) (7:3 (v / v)) for 1 minute, removed, and the thickness of the thin film was measured. The chemical resistance of the underlayer film was evaluated from the thickness reduction rate measured before and after immersion according to the following calculation formula 3. The smaller the thickness reduction rate, the better the chemical resistance. Specifically, a thickness reduction rate of less than 2% was evaluated as "even", a thickness reduction rate of 2% to less than 5% was evaluated as "normal", and a thickness reduction rate of 5% or more was evaluated as "poor". The results are shown in Table 4 below. [Formula 3] Lower layer film thickness reduction rate (%) = {(thin film thickness before immersion - thin film thickness after immersion) / thin film thickness before immersion} x 100

[0092] [Table 4]

[0093] From Table 4, it can be seen that the thickness reduction rate before and after immersion in the mixed solution of EEP and EL in the Examples is smaller than that in the Comparative Examples. Therefore, it can be seen that the chemical resistance of the resist underlayer film in the Examples is superior to that of the thin film in the Comparative Examples.

[0094] Although specific embodiments of the present invention have been described and illustrated above, the present invention is not limited to the described embodiments, and it is obvious to those skilled in the art 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 separately from the technical spirit or perspective of the present invention, and the modified embodiments should belong to the scope of the claims of the present invention. [Explanation of symbols]

[0095] 100 Substrates 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 having a structural unit represented by the following chemical formula 1, and a solvent: 【Chemistry 1】 In the above Chemical Formula 1, L １ ~L ４ are each independently a substituted or unsubstituted C1 to C20 alkyl or alkylene group; L ５ ~L ８ are each independently a single bond, a substituted or unsubstituted C1 to C20 alkyl group or alkylene group, a substituted or unsubstituted C2 to C20 alkenyl group or alkenylene group, a substituted or unsubstituted C2 to C20 alkynyl group or alkynylene group, a substituted or unsubstituted C3 to C20 cycloalkyl group or cycloalkylene group, a substituted or unsubstituted C6 to C30 aryl group or arylene group, or a combination thereof; M １ ~M ８ each independently represents a single bond, —C(═O)—, —OC(═O)—, or a combination thereof; x １ ~x ４ are each independently 0 or 1, １ ~x ４ Two or more of are 1, y １ ~y ４ are each independently 0 or 1; Z １ ~z ４ are each independently 0 or 1; R １ and R ２ are each independently hydrogen, deuterium, a hydroxy group, a substituted or unsubstituted C1-C10 alkoxy 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, or a combination thereof; * indicates a connection point with other structural units.

2. L of Formula 1 １ ~L ４ are each independently a substituted or unsubstituted C1 to C10 alkyl or alkylene group; L ５ ~L ８ each independently represents a single bond, a substituted or unsubstituted C1 to C10 alkyl group or alkylene group, a substituted or unsubstituted C2 to C10 alkenyl group or alkenylene group, a substituted or unsubstituted C2 to C10 alkynyl group or alkynylene group, or a combination thereof; M １ ~M ８ each independently represents a single bond, —C(═O)—, or a combination thereof; x １ ~x ４ Two of them are 1 and the other two are 0, R １ and R ２ are each independently a hydrogen atom, a deuterium atom, a hydroxyl group, a substituted or unsubstituted C1 to C10 alkoxy group, a substituted or unsubstituted C1 to C10 alkyl group, or a combination thereof.

3. L of Formula 1 ５ ~L ８ are each independently a single bond, a substituted or unsubstituted C1 to C10 alkyl or alkylene group, or a combination thereof; M １ ~M ８ are each independently a single bond, -C(=O)-, or a combination thereof; R １ and R ２ The resist underlayer film composition according to claim 1 , wherein is hydrogen.

4. In the above formula 1, x １ and x ４ is 1, and x ２ and x ３ The resist underlayer film composition according to claim 1 , wherein

5. The composition for a resist underlayer film according to claim 1, wherein the chemical formula 1 is represented by at least one of the following chemical formulas 1-1 and 1-2: 【Chemistry 2】 【Chemistry 3】 In the above Chemical Formula 1-1 and Chemical Formula 1-2, R １１ , R １２ , R ２１ , and R ２２ are each independently hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group; R １３ , R １４ , R ２３ , and R ２４ are each independently hydrogen, deuterium, a hydroxyl group, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 alkoxy group, or a combination thereof; n1 and n2 each independently represent an integer from 1 to 10; * indicates a connection point.

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

7. 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.

8. 2. The resist underlayer film composition according to claim 1, further comprising one or more polymers selected from an acrylic resin, an epoxy resin, a novolac resin, a glycoluril resin, and a melamine resin.

9. 2. 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 combinations thereof.

10. forming a film to be etched on a substrate; Applying the composition for a resist underlayer film according to claim 1 onto the film to be etched to form a resist underlayer film; forming a photoresist pattern on the resist underlayer film; and A method for forming a pattern, comprising the steps of sequentially etching the resist underlayer film and the film to be etched using the photoresist pattern as an etching mask.

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