WO2008082108A1

WO2008082108A1 - Organic copolymer for preparing organic antireflective coating, method of preparing the same, and composition comprising the same

Info

Publication number: WO2008082108A1
Application number: PCT/KR2007/006691
Authority: WO
Inventors: Jun Woo Kim; In Sik Cho
Original assignee: Hyosung Corporation
Priority date: 2006-12-29
Filing date: 2007-12-20
Publication date: 2008-07-10
Also published as: KR20080062645A; KR100889173B1

Abstract

A cyanato crosslinker-containing copolymer is provided. The copolymer can be used for the formation of an antireflective coating in photolithography for forming sub-micron circuits using deep UV light. Further provided are a method for preparing the copolymer, an organic antireflective coating composition comprising the copolymer, and an organic antireflective coating formed using the coating composition. When the organic antireflective coating is used to manufacture a gigabit (Gb) level, large-scale integrated DRAM device, it has good adhesion to a substrate and suppresses the occurrence of reflective notching between circuit layers and standing wave effects. Therefore, the organic antireflective coating can contribute to an increase in the yield of the semiconductor device.

Description

ORGANIC COPOLYMER FOR PREPARING ORGANIC ANTI- REFLECTIVE COATING, METHOD OF PREPARING THE SAME, AND COMPOSITION COMPRISING THE SAME

Technical Field

[1] The present invention relates to a cyanato crosslinker-containing organic copolymer for the formation of a bottom antireflective coating layer capable of suppressing reflective notching that occurs on a substrate underlying a photoresist and of eliminating standing wave effects caused due to the use of a light source and a thickness variation in the photoresist during photolithography, which is an exposure process for the formation of large-scale semiconductor integrated circuits on a sub-micron scale using deep UV light of short wavelength. The present invention also relates to a method for preparing the organic copolymer and an antireflective coating composition comprising the organic copolymer.

[2]

Background Art

[3] Antireflective coating (ARC) is a very thin photosensitive material layer that absorbs light, and is used in photolithographyfor stably forming sub-micron circuits on the order of 70-150 nm or less, which are essential for the manufacture of gigabit (Gb) level, very large-scale integrated semiconductor devices. Accordingly, antireflective coating is required to have interfacial and optical properties that match those of high- resolution photoresist (PR) materials currently used in semiconductor manufacturing processes. This antireflective coating is called a bottom antireflective coating (BARC or bottom ARC) because it is primarily coated on a substrate surface under the photoresist for exposing the process of deep ultraviolet light. The organic bottom antireflective coating layer with a high absorbance is generally used in current advanced photolithographic techniques for the formation of large-scale semiconductor integrated circuits. The ARC layer must have an excellent property of light absorption, as the wavelength of light source is shortened (G-line, I-line, KrF, ArF, F₂, etc.) in accordance with the technology of submicron-level, large-scale integrated chip advanced [M. Padmanaban et al., Proc. SPIE, 3678, 550 (1999); G. E. Bailey et al. Proc. SPIE, 3999, 521 (2000); M. Padmanaban et al, Proc. SPIE, 333, 206 (1998)].

[4] With the recent remarkable progress in the manufacturing technology of very large- scale integrated semiconductor devices, it is impossible to stably form sub-micron circuits on the order of 70-150 nm by conventional photolithographic techniques wherein a photosensitive material (i.e. a photoresist) is applied to a silicon wafer by spin coating, followed by irradiation with light to form circuits. Thus, there has been an increasing demand for the formation of special thin films under photoresist layers to prevent light from being reflected during irradiation.

[5] The ARC layer serves to eliminate standing wave effects caused by interference between incident light and light reflected from a substrate within a photoresist layer upon being irradiated with light, and to prevent or markedly reduce the reflection of light due to a topography resulting from existing circuit layers or reflective notching at edges. Accordingly, the antireflective coating layer plays a role in accurately controlling a desired critical dimension (CD) of sub-micron circuits to achieve increased process latitude of manufacturing conditions. Materials for antireflective coating are divided into organic materials by spin coating and inorganic materials by chemical vapor deposition according to their compositions. At present, the antireflective coating layer formed of organic materials is predominantly used because of convenience in terms of processing.

[6] Since photolithographic techniques using deep UV light of short wavelength, particularly 248 nm-krypton fluoride (KrF) excimer laser, have come into practical use, the role of antireflective coatings has gained importance. Organic polymers using aromatic derivatives containing chromophores, such as anthracene and naphthalene, with a high absorbance in the deep UV region are widely used as antireflective coating materials to form sub-micron circuits of 150 nm or smaller, i.e. the order of 100 nm [J. Meador et al., Proc. SPIE, 3678, 800 (1999); G. Taylor et al., Proc. SPIE, 3678, 174 (1999); X. Shao et al., J. Photopolym. Sci. Technol., 14, 481 (2001); MyoungSoo Kim et al., Proc. SPIE, 5753, 644 (2005); K. Mizutani et al., Proc. SPIE, 3678, 518 (1999)]. In this connection, some techniques are found in U.S. Patent Nos. 5,693,691, 5,886,102, 5,919,599, 6,033,830, 6,080,530, 6,156,479 and 6,602,652.

[7] To form sub-micron circuits, the organic bottom antireflective coatings layer used in deep UV irradiation processes must meet the following requirements [H. Yoshino et al., Proc. SPIE, 3333, 655 (1998); P. Trefonas et al., Proc. SPIE, 3678, 701 (1999); S. Malik et al., J. Photopolym. Sci. Technol., 14, 489 (2001); R. Huang et al., Proc. SPIE, 5753, 637 (2005); C. Y. Chang et al., Proc. SPIE, 6153, 61530M (2006)]:

[8] - The organic bottom antireflective coating layer is required to have appropriate optical constants, such as refractive index (n) and extinction coefficient (k), for light sources used in semiconductor manufacturing processes;

[9] - The organic bottom antireflective coating layer is required to have a higher selectivity with respect to a plasma dry etch rate than overlying photoresists and leave no defects upon dry etching;

[10] - The organic bottom antireflective coating layer must be formed of organic polymers having reactive groups capable of forming suitable crosslinked structures in the organic polymer chains in order to prevent intermixing with overlying photoresist layers;

[H] - The ability to optimize the thickness of thin films, good film formation properties and coating uniformity upon spin coating are required in organic bottom antireflective coating.

[12]

Disclosure of Invention Technical Problem

[13] It is therefore a feature of an embodiment to provide a novel cyanato crosslinker- containing organic copolymer that can be used for the formation of sub-micron circuits using 248 nm-krypton fluoride (KrF) excimer laser or 193 nm-argon fluoride (ArF) excimer laser as an exposure light source in a very large-scale integrated semiconductor device manufacturing process, and a method for preparing the organic copolymer.

[14] It is therefore another feature of an embodiment to provide an organic polymeric material that is capable of preventing reflective notching from an underlying layer upon irradiation with short- wavelength light and exhibits good adhesiveness and crosslinking performance, and a method for preparing the organic polymeric material.

[15] It is therefore still another feature of an embodiment to provide a bottom antireflective coating composition using the organic polymeric material and a bottom antireflective coating formed using the coating composition.

[16]

Technical Solution [17] In accordance with one aspect of the present invention for accomplishing the above objects, there is provided an N-cyanatophenylmaleimide-containing copolymer represented by Formula 1 :

(1)

[19] [20] wherein R is H, tetrahydropyranyl, -COOR₅ (R₅ is methyl, ?-butyl or C₂-C₃ alkyl), (SiRe)₃ (R₆ is methyl, t-butyl or C₂-C₃ alkyl) or t-butyl, [21] R₁ and R₃ are each independently hydrogen, Ci-C₆ alkyl, alkoxyalkyl, hydroxy alkyl or haloalkyl,

[22] R₂ and R₄ are each independently hydrogen or methyl,

[23] k, 1, m and n representing the mole fractions of the monomers satisfy the relations of

0 = k/(k + 1 + m + n) = 0.3, 0 = l/(k + 1 + m + n) =0.7, 0.1 =m/(k + 1 + m + n) = 0.5, 0.1

= n/(k + 1 + m + n) = 0.4, with the proviso that two kinds of N-phenylmaleimide monomers (k) may be provided depending on the choice of R. [24] In accordance with another aspect of the present invention, there is provided a method for preparing the copolymer. [25] In accordance with another aspect of the present invention, there is provided an organic antireflective coating composition comprising the copolymer. [26] In accordance with yet another aspect of the present invention, there is provided an organic antireflective coating formed using the coating composition. [27]

Advantageous Effects

[28] The organic antireflective coating using the copolymer as a basic structure has new thermally crosslinkable cyanato crosslinkers introduced into the polymer chain by covalent bonding. The presence of the crosslinkers makes the organic antireflective coating very safe against heat because almost no gas is generated during high- temperature crosslinking. In addition, the organic antireflective coating of the present invention has good adhesion to a substrate and has a sufficiently high absorbance. Based on these advantages, the organic antireflective coating of the present invention suppresses reflective notching that occurs on an underlying layer and can eliminate standing wave effects caused due to the use of a light source and a thickness variation in the photoresist upon exposure to light. Furthermore, the organic antireflective coating of the present invention can stably transfer circuits to a substrate due to its high etching capability with respect to plasma.

[29]

Best Mode for Carrying Out the Invention

[30] Preferred embodiments of the present invention will now be described in greater detail.

[31] The present invention provides an organic copolymer of three or four different monomers selected from monomers containing anthracene and hydroxyphenyl- maleimide chromophores with a high absorbance at exposure wavelengths of 248 and 193 nm, respectively, a monomer containing cyanate groups that are crosslinked to form an antireflective coating, a comonomer for controlling the physical properties of the copolymer, and other monomers. Specifically, the organic copolymer of the present invention may be a terpolymer, tetrapolymer or pentapolymer prepared from the three or four different monomers. Preferably, the hydroxyphenylmaleimide monomer is properly protected for ease of preparation of the polymer or has the ability to be crosslinked.

[32] The organic polymer of the present invention satisfying all characteristics described above has a structure represented by Formula 1 :

(1)

[34] wherein R is H, tetrahydropyranyl, -COOR₅ (R₅ is methyl, t-butyl or C₂-C₃ alkyl),

(SiRe)₃ (R₆ is methyl, t-butyl or C₂-C₃ alkyl) or t-butyl,

[35] Ri and R₃ are each independently hydrogen, Ci-C₆ alkyl, alkoxyalkyl, hydroxyalkyl or haloalkyl,

[36] R₂ and R₄ are each independently hydrogen or methyl,

[37] k, 1, m and n representing the mole fractions of the monomers satisfy the relations of

0 = k/(k + 1 + m + n) = 0.3, 0 = l/(k + 1 + m + n) =0.7, 0.1 =m/(k + 1 + m + n) = 0.5, 0.1 = n/(k + 1 + m + n) = 0.4, with the proviso that two kinds of N-phenylmaleimide monomers (k) may be provided depending on the choice of R.

[38] The organic polymer of Formula 1 according to the present invention may be generally represented by (M_a)_k-(M_b)r(M_c)_m-(M_d)i. Herein, M_a is a hydroxyphenylmaleimide monomer, exactly N-(4-hydroxyphenyl)maleimide, or has an N- (4-hydroxyphenyl)maleimide structure protected with an appropriate protecting group (R in Formula 1), M_b is a methacrylic acid ester structure having an appropriate group (Ri in Formula 1), M_c is an N-(4-cyanatophenyl)maleimide structure having the ability to be crosslinked, and M_d represents a 9-nthracenemethylmethacrylate monomer that has the ability to absorb light.

[39] The cyanato crosslinker-containing polymer of Formula 1 according to the present invention exhibits markedly improved adhesion to a wafer as compared to hydroxyl crosslinker-containing derivatives and has improved crosslinking properties to prevent intermixing with a photoresist layer.

[40] The present invention also provides a method for preparing the polymer of Formula

1. Specifically, the polymer of Formula 1 can be prepared by reacting the monomers in the presence of a radical polymerization initiator under an inert atmosphere, such as nitrogen or argon, for 2 to 24 hours. Any known thermal polymerization initiator may be used as the radical polymerization initiator and examples thereof include azobis- isobutyronitrile (AIBN), azobisvaleronitrile (AIVN), benzoyl peroxide (BPO) and di-t - butyl peroxide (DTBP). The reaction is preferably carried out at a temperature ranging from 50 to 9O⁰C. The polymerization reaction may be carried out in a solvent, such as dioxane, tetrahydrofuran or an aromatic solvent (e.g., benzene). The molecular weight of the polymer required in a semiconductor exposure process may be optimized by varying the weight ratio between the monomers and the polymerization solvent or the amount of the radical polymerization initiator used. The polymerization conditions of the polymer of Formula 1 may be varied such that the polymer has a molecular weight of 5,000 to 100,000, as measured by gel permeation chromatography (GPC). The optimal molecular weight of the polymer is determined in view of coatability for the formation of an antireflective coating.

[41] The present invention also provides a composition for forming an organic antireflective coating. The organic antireflective coating composition of the present invention is prepared by dissolving 0.2 to 20% by weight of the polymer of Formula 1 in an organic solvent, such as propylene glycol monomethyl ether acetate (PGMEA), ethyl 3-ethoxypropionate, ethyl lactate, methyl 3-methoxypropionate or cyclo- hexanone, and adding an appropriate amount of at least one functional additive to the solution. The solvent is preferably one that has superior ability to form a coating and is used in photolithographic techniques for the formation of semiconductor integrated circuits. The functional additive may be a crosslinking binder. For example, the crosslinking binder may be used in an amount of 0.1 to 10% by weight, based on the weight of the polymer.

[42] The composition in a solution state is passed through a filter to remove fine particles, spin-coated on a silicon wafer, and crosslinked at a suitable temperature to form a desired antireflective coating. The antireflective coating thus formed plays a role in eliminating problems caused by the reflection of light during processing of sub-micron circuits with deep UV light of short wavelength, leading to the manufacture of semiconductor devices without any particular difficulty.

[43] The cyanato crosslinker-containing polymer of the present invention is suitable for use in an organic antireflective coating for the formation of sub-micron circuits at exposure wavelengths of 248 nm, 193 nm and 157 nm as deep UV light sources of short wavelength. The antireflective coating formed using the coating polymer of the present invention exhibits good adhesiveness and excellent superior crosslinking properties when compared to hydroxyl crosslinker-based antireflective coatings. From these advantages, it is confirmed that the antireflective coating of the present invention is useful for the formation of sub-micron circuits of semiconductor devices. [44]

Mode for the Invention

[45] Hereinafter, the present invention will be explained in more detail with reference to the following examples. However, these examples are given for the purpose of illustration and not intended to limit the present invention.

[46]

[47] EXAMPLES

[48] EXAMPLE 1: Synthesis of N-hvdroxyphenylmaleimide (HOPMI. 'Monomer Y)

maleic anhydride 4-aminophenol HOPMAA 1 (HOPMI)

[50] Maleic anhydride (39.2Og, 0.40 mol) and 4-aminophenol (41.4Og, 0.38 mol) were dissolved in 50 ml of dimethylformamide (DMF) in a 250 ml round-bottom flask equipped with a reflux condenser. The mixture was allowed to react for 90 minutes. Filtration of the reaction mixture gave a yellow solid product. The product was washed with distilled water 3-4 times and dried to afford 75.4Og (yield 96.0%) of N- (4-hydroxyphenyl)maleamic acid (HOPMA, m.p. 18O⁰C).

[51] The product (75.4Og, 0.36 mol) was introduced into a 250 ml round-bottom flask equipped with a reflux condenser, and then phosphorus pentoxide (P₂O₅, 10.0g, 0.07 mol) was slowly added thereto to react at 8O⁰C. After the by-product (water) was removed, a dilute solution of 4 ml of sulfuric acid in 20 ml of DMF was slowly added. The reaction was carried out for 2 hours. The reaction product was precipitated in an excess of distilled water to give a monomeric product. The monomeric product was re- crystallized from propanol to afford 56.37g (yield 81.9%) of N- hydroxyphenylmaleimide (HOPMI, 'monomer 1') as an orange crystal (m.p. 182⁰C).

[52]

[53] EXAMPLE 2: Synthesis of N-(4-tetrahvdropyranyloxyphenyl)maleimide

(THP-OPMI. Monomer 2)

HOPMl Dihydropyran 2 (THP-OPMI)

[55] Monomer 1 (47.3Og, 0.25 mol) and dihydropyrane (105.2Og, 1.25 mol) were dissolved in 150 ml of tetrahydrofuran (THF) in a 500 ml round-bottom flask. To the mixture was slowly added dropwise a dilute solution of 0.5 ml of concentrated sulfuric acid in 100 ml of THF. The resulting mixture was allowed to react with stirring at room temperature for 12 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure. The residue was precipitated in an excess of distilled water and filtered. The filtered product was washed with distilled water several times and recrystallized from propanol to afford 53.2Og (yield 77.9%) of N-tetrahydropyranyloxymaleimide (THP-OPMI, 'Monomer 2' as an orange crystal (m.p. 12O⁰C). Monomer 2 is a protected form of monomer 1.

[56]

[57] EXAMPLE 3: Synthesis of N-f4-cvanatophenvDmaleimide (CvPMI. Monomer 3)

HOPMI 3 (CyPMI)

[59] Monomer 1 (15.0Og, 0.79 mol) and cyanogen bromide (lO.lOg, 0.95 mol) were dissolved in 120 ml of acetone in a 250 ml round-bottom flask and cooled in an ice bath at O⁰C. To the mixture was slowly added triethylamine (9.6Og, 0.95 mol) over 20 minutes. The resulting mixture was allowed to react for 4 hours. The reaction mixture was filtered to remove ammonium salts, and then the filtrate was precipitated in an excess of distilled water. The precipitate was collected and recrystallized from a mixture of hexane and acetone (6:1) to afford 13.74g (yield 80.90%) of N- cyanatophenylmaleimide (CyPMI, 'monomer 3' as an orange crystal (m.p. 132⁰C).

[60]

[61] EXAMPLE 4: Synthesis of terpolvmer using monomer 3. anthracene methyl- methacylate and methyl methacrylate

[62] Monomer 3 (7.84g, 36 mmol), anthracene methylmethacylate (AMMA, 10.22g, 36 mmol), methyl methacrylate (MMA, 7.32g, 72 mmol) and 3 mol% of AIBN as a radical initiator were dissolved in dioxane (50 ml) in a polymerization reactor. The mixture was polymerized under a nitrogen atmosphere at a temperature of 6O⁰C for 10 hours. The polymerization product was precipitated in an excess of methanol, filtered and dried to afford terpolymer P (CyPMFAMMA/MMA) in a yield of 86%. The terpolymer was found to have a weight average molecular weight of about 43,000, as measured by GPC. A film was formed with no difficulty using the terpolymer.

[63]

[64] EXAMPLE 5: Synthesis of tetrapolymer using monomer 1. monomer 3. AMMA and

MMA

[65] Monomer 1 (7.1 Ig, 36 mmol), monomer 3 (7.84g, 36 mmol), AMMA (10.22g, 36 mmol), MMA (7.32g, 72 mmol) and 3 mol% of AIBN as a radical initiator were dissolved in dioxane (50 ml) in a polymerization reactor. The mixture was polymerized under a nitrogen atmosphere at a temperature of 6O⁰C for 10 hours. The polymerization product was precipitated in an excess of methanol, filtered and dried to afford tet- rapolymer P (HOPMI/CyPMI/AMMA/MMA) in a yield of 88%. The tetrapolymer P was found to have a weight average molecular weight of about 41,000, as measured by GPC. A film was formed with no difficulty using the tetrapolymer.

[66]

[67] EXAMPLE 6: Synthesis of tetrapolvmer using monomer 2. monomer 3. AMMA and

MMA

[68] Monomer 2 (10.0g, 36 mmol), monomer 3 (7.84g, 36 mmol), AMMA (10.22g, 36 mmol), MMA (7.32g, 72 mmol) and 3 mol% of AIBN as a radical initiator were dissolved in dioxane (50 ml) in a polymerization reactor. The mixture was polymerized under a nitrogen atmosphere at a temperature of 6O⁰C for 10 hours. The polymerization product was precipitated in an excess of methanol, filtered and dried to afford tetrapolymer P (THP-OPMI/CyPMI/AMMA/MMA) in a yield of 91%. The tetrapolymer P was found to have a weight average molecular weight of about 42,500, as measured by GPC. A film was formed with no difficulty using the tetrapolymer.

[69]

[70] EXAMPLE 7: Synthesis of pentapolymer using monomer 1. monomer 2. monomer

3. AMMA and MMA

[71] Monomer 1 (7.11g, 36 mmol), monomer 2 (10.0g, 36 mmol), monomer 3 (7.84g, 36 mmol), AMMA (10.22g, 36 mmol), MMA (7.32g, 72 mmol) and 3 mol% of AIBN as a radical initiator were dissolved in dioxane (50 ml) in a polymerization reactor. The mixture was polymerized under a nitrogen atmosphere at a temperature of 6O⁰C for 10 hours. The polymerization product was precipitated in an excess of methanol, filtered and dried to afford pentapolymer P (HOPMI/THP-OPMI/CyPMI/AMMA/MMA) in a yield of 87%. The pentapolymer P was found to have a weight average molecular weight of about 40,500, as measured by GPC. A film was formed with no difficulty using the pentapolymer.

[72]

[73] EXAMPLE 8: Preparation and application of organic antireflective coating compositions

[74] Each of the copolymers prepared in Examples 4 to 7 was dissolved in propylene glycol monomethyl ether acetate (PGMEA), which is known to have superior ability to form a coating. At this time, the weight ratio of the copolymer to the solvent was adjusted to about 1:20 to about 1:50. Various additives, such as a thermal crosslinking binder and a stabilizer, were added to the solution, stirred and passed through a mi- croporous membrane filter to prepare an organic antireflective coating solution for irradiation with deep UV light of short wavelength. The coating solution was spin- coated on a silicon wafer and crosslinked at 100-250⁰C for 10-120 seconds to form an antireflective coating capable of preventing intermixing with a photoresist. A commercial photoresist was spin-coated on the antireflective coating in accordance with a general photolithographic process for forming sub-micron circuits. The organic antireflective coating compositions using the respective copolymers prepared in Examples 4 to 7 were found to be in acid equilibrium with photoresists upon development after irradiation with light. As a result, no undercutting or footing was observed under fine patterns of the photoresists. In addition, a dimensional variation in sub-micron circuits of the patterns resulting from reflective notching was very small, indicating that high-resolution sub-micron circuits on the order of 70-150 nm were stably formed. [75]

Industrial Applicability

[76] The organic antireflective coating using the polymer of the present invention can be irradiated with excimer laser of 248 nm, 193 nm and 157 nm to stably manufacture 1 -gigabit DRAM or higher memory devices or system integrated circuits on the order of 70-150nm. Therefore, the organic antireflective coating of the present invention can contribute to an increase in the yield of semiconductor devices.

Claims

Claims [1] An N-cyanatophenylmaleimide-containing copolymer represented by Formula 1 :

(1) wherein R is H, tetrahydropyranyl, -COOR₅ (R₅ is methyl, ?-butyl or C₂-C₃ alkyl), (SiR₆)₃ (R₆ is methyl, ?-butyl or C₂-C₃ alkyl) or ?-butyl,

Ri and R₃ are each independently hydrogen, Ci-C₆ alkyl, alkoxyalkyl, hy- droxyalkyl or haloalkyl,

R₂ and R₄ are each independently hydrogen or methyl, k, 1, m and n representing the mole fractions of the monomers satisfy the relations of 0 = k/(k + 1 + m + n) = 0.3, 0 = l/(k + 1 + m + n) =0.7, 0.1 =m/(k + 1 + m + n) = 0.5, 0.1 = n/(k + 1 + m + n) = 0.4, with the proviso that one or two kinds of N-phenylmaleimide monomers (k) are provided depending on the choice of R.

[2] The copolymer according to claim 1, wherein the copolymer has an average molecular weight of 10,000 to 100,000. [3] A method for preparing an N-cyanatophenylmaleimide-containing copolymer represented by Formula 1, the method comprising reacting the monomers in a solvent selected from the group consisting of dioxane, tetrahydrofuran, methyl ethyl ketone and aromatic solvents in the presence of a polymerization initiator selected from the group consisting of azobisisobutyronitrile (AIBN), di-?-butyl peroxide (DTBP), benzoyl peroxide (BPO) and azobisvaleronitrile (AIVN).

(1) wherein R is H, tetrahydropyranyl, -COOR₅ (R₅ is methyl, ?-butyl or C₂-C₃ alkyl), (SiR₆)₃ (R₆ is methyl, t-butyl or C₂-C₃ alkyl) or t-butyl,

R₁ and R₃ are each independently hydrogen, Ci-C₆ alkyl, alkoxyalkyl, hy- droxyalkyl or haloalkyl,

R₂ and R₄ are each independently hydrogen or methyl, k, 1, m and n representing the mole fractions of the monomers satisfy the relations of 0 = k/(k + 1 + m + n) = 0.

3, 0 = l/(k + 1 + m + n) =0.7, 0.1 =m/(k + 1 + m + n) = 0.5, 0.1 = n/(k + 1 + m + n) = 0.4, with the proviso that one or two kinds of N-phenylmaleimide monomers (k) are provided depending on the choice of R,

[4] An organic antireflective coating composition comprising an organic solvent, at least one additive and a polymer represented by Formula 1 :

(1) wherein R is H, tetrahydropyranyl, -COOR₅ (R₅ is methyl, t-butyl or C₂-C₃ alkyl), (SiR₆)₃ (R₆ is methyl, t-butyl or C₂-C₃ alkyl) or t-butyl, R₁ and R₃ are each independently hydrogen, Ci-C₆ alkyl, alkoxyalkyl, hy- droxyalkyl or haloalkyl,

[5] The composition according to claim 4, wherein the composition is prepared by dissolving 0.2 to 20% by weight of the polymer in the organic solvent and adding 0.2 to 10% by weight of the functional additive to the solution.

[6] The composition according to claim 4, wherein the organic solvent is selected from the group consisting of butyrolactone, cyclopentanone, cyclohexanone, dime thylacetamide, dimethylformamide, dimethylsulfoxide, N- methylpyrrolidone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, and mixtures thereof.

[7] An organic antireflective coating formed using the composition according to any one of claims 4 to 6.