WO2008150058A1

WO2008150058A1 - Hardmask composition having antireflective properties and method of patterning material on substrate using the same

Info

Publication number: WO2008150058A1
Application number: PCT/KR2007/007059
Authority: WO
Inventors: Kyong Ho Yoon; Jong Seob Kim; Dong Seon Uh; Hwan Sung Cheon; Chang Il Oh; Min Soo Kim; Jin Kuk Lee
Original assignee: Cheil Industries Inc
Current assignee: Cheil Industries Inc
Priority date: 2007-06-05
Filing date: 2007-12-31
Publication date: 2008-12-11
Anticipated expiration: 2009-12-05
Also published as: TWI380133B; US7981594B2; CN101681096A; US8445187B2; US20080305441A1; US20110275019A1; KR100908601B1; TW200906977A; KR20080107210A; JP2010529499A

Abstract

A hardmask composition having antireflective properties is provided. The hardmask composition is suitable for lithography and provides excellent optical properties and mechanical properties. In addition, the hardmask composition can be readily applied by spin-on application techniques. Particularly, the composition is highly resistant to dry etching. Therefore, the composition can be used to provide a multilayer thin film that is capable of being patterned with a high aspect ratio. Further provided is a method for forming a pattern using the composition.

Description

HARDMASK COMPOSITION HAVING ANTIREFLECTIVE

PROPERTIES AND METHOD OF PATTERNING MATERIAL

ON SUBSTRATE USING THE SAME

TechnicaL Field

[1] The present invention relates to a hardmask composition haying antirefiective properties suitable for lithography. More specifically, the present invention relates to a hardmask composition comprising one or more aromatic ring-containing polymers with a strong absorption in the short wavelength region (e~g., 157 nm, 193 nm and 248 nm).

[2]

Background Art

[3] There is a continuous demand to reduce the size of structural shapes in the microelectronics industry and other related industries, including the manufacture of microscopic structures (for example, micromachiαes and magneto-resist heads). In the micfoέlectronics industry, there exists a need to reduce the size of microelectronic devices in order to provMea number of circuits in a given chip size,

[4.] Effective lithographic techniques are essential to achieve a reduction in the size of structural shapes. Lithography affects the manufacture of microscopic structures from the viewpoint of direct imaging of patterns on particular substrates and production of masks typically used for such imaging.

[S] A typical lithographic process involves patternwise exposure of a radiation-sensitive resist to imaging radiation to form a patterned resist layer. Thereafter, an, image is ■developed by bringing the exposed resist layer into contact with a certain substance (typically, an aqueous alkaline developing solution), Then, the substance present in openings of the patterned resist, layer is etched to transfer a pattern to an underlying material. After completion of the transfer, remaining portions of the resist layer are removed.

[6] R>r better resolution in most lithographic processes, an antireflective coating (ARQ is used to minimize the reflectivity between an imaging layer, e>g., n radiation- sensitive resist material layer, and an underlying layer. Plowever, since many portions of the imaging layer are removed during etching of ARC after patterning, patterning may be further required in the subsequent etching step. [7] In other words, in some lithographic imaging processes, the resist does not provide resistance to the subsequent etching step to an extent sufficient to effectively transfer the desired pattern to a layer underlying the resist, In actual applications (for example, in the case where an extremely thin resist layer is required, an underlying material to be etched is thick, a large etching depth is needed, and/br the use of a particular etchant is required depending on the type of an underlying material), a so-called 'hardmask layer¹ is used as an intermediate layer between the patterned resist layer and the underlying material that can be patterned by transfer from the patterned resist. The hardmask layer must be able to receive the pattern from the patterned resist layer and withstand etching required to transfer the pattern to the underlying material,

[8]

Disclosure of Invention Technical Problem

[9] Although a number of hardmask materials are known, there is a continuous need for an improved hardmask composition. Snce conventional hardmask materials are difficult to apply to substrates, the use of chemical and physical vapor deposition, special solvents, andfor high-temperature baking may be required. However, these methods not only necessitate the use of expensive equipment or the introduction of advanced techniques but also involve relatively complicated processes, thus incurring considerable production costs of devices. Thus, a hardmask composition that can be applied by spin-coating techniques would be desirable. A hardmask composition that can be selectively etched using an overlying photoresist layer as a mask in an easy manner while being resistant to etching necessary to pattern an underlying metal or silicon compound layer using a hardmask layer as a hardmask, would also be desirable. A hardmask composition that provides superior storage properties and avoids unwanted interactions (e.g_Υ, acid pollution from a hardmask) with an imaging resist layer would further be desirable, A hardmask composition that has particular optical properties against imaging radiation at shorter wavelengths {e.g., 157 nm, 193 nm, and 248 nm) would also be desirable.

[10] Numerous technical difficulties remain in patterning relatively thick underlying layers by dry etching, ϊbr example, an overlying hardmask layer formed by spin coating may have an isotropic (e.g., bowed) etch profile during dry etching, which makes it difficult to allow the hardmask layer to function as a hardmask of a relatively thick underlying layer. Attempts have been made to prevent the occurrence of isotropic etch profiles, for example, by varying dry etching conditions. However, device makers suffer from limitations in the operation of mass-production facilities. Under such circumstances, the present inventors have endeavored to prepare a high-density networking polymer with high carbon content in an amorphous structure that can be used to form a hardmask having an anisotropic profile.

[11]

Technical Solution [12] The present invention has been made in view of the problems of the prior art, and it is one object of the present invention to provide a novel hardmask composition suitable for use in a lithographic process that exhibits high etch selectivity, is sufficiently resistant to multiple etching, and minimizes the reflectivity between a resist and an underlying layer.

[13] It is another object of the present invention to provide a method for patterning an underlying material layer on a substrate by using the hardmask composition, [14] In accordance with one aspect of the present invention for accomplishing the above objects, there is provided an antireflective hardmask composition comprising [15] (a) at least one aromatic ring-containing polymer selected from the group consisting of polymers represented by formulae 1, 2 and 3:

[17] wherein each R_x is selected from

[19] (R is H or alkyl), each R₂ is selected from hydrogen (-H), hydroxyl (-OH), C₁-Ci₀ alkyl, C₆-C₁₀ aryl, allyl and halogen, R₃ is selected from

[211 and 1 < n < 750;

[23] wherein R₄ is selected from

[27] and 1 < n < 750; and

[29] wherein R₁, R₂, R₃, R₄, R₅ and n are as defined in Ibrmulae 1 and 2, 1 < m < 750, and 2 < m + n < 1,500, and

[30] (b) an organic solvent.

[31] The hardmask composition of the present invention may further comprise (c) a cros slinking component.

[32] The hardmask composition of the present invention may further comprise (d) an acid or base catalyst

[33] In this case, the hardmask composition of the present invention may comprise 1 to 20% by weight of the aromatic ring-containing polymer (a), 75 to 98.8% by weight of the organic solvent (b), Ql to 5% by weight of the crosslinMng component (c), and QOOl to Q05% by weight of the acid or base catalyst (d).

[34] The aromatic ring-containing polymer preferably has a weight average molecular weight of 1 ,000 to 30,00Q

[35] The hardmask composition of the present invention may further comprise a surfactant

[36] The crosslinking component may be selected from the group consisting of melamine resins, amino resins, glycoluril compounds, and bisepoxy compounds.

[37] The acid catalyst may be selected from the group consisting of _p-toluenesulfonic acid monohydrate, pyridinium p-toluenesulfonate, 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, and alkyl esters of organic sulfonic acids.

[38] The base catalyst may be selected from ammonium hydroxides represented by NH ₄ OH or NR₄OH (R = alkyl).

[39] In accordance with another aspect of the present invention, there is provided a method for patterning a material on a substrate by using the hardmask composition.

[40] Specifically, the method of the present invention comprises the steps of (a) providing a material layer on a substrate, (b) forming an antireflective hardmask layer using the composition on the material layer, (c) forming a radiation-sensitive imaging layer on the antireflective hardmask layer, (d) patternwise exposing the radiation-sensitive imaging layer to radiation to form a pattern of radiation-exposed regions in the imaging layer, (e) selectively removing portions of the radiation-sensitive imaging layer and the antireflective hardmask layer to expose portions of the material layer, and (f) etching the exposed portions of the material layer to pattern the material layer.

[41] The method of the present invention may further comprise the step of forming a silicon-containing hardmask layer prior to step (c). [42] The method of the present invention may further comprise the step of forming a bottom antireflective coating (BARQ on the silicon-containing hardmask layer prior to step (c).

[43]

Best Mode for Carrying Out the Invention [44] Exemplary embodiments of the present invention will now be described in greater detail. [45J The present invention provides an antireflective hardmask composition characterized by the presence of one or more aromatic ring-containing polymers with a strong absorption in the short wavelength region (particularly, 248 nm or less).

[46] Specifically, the antireflective hardmask composition comprises (a) at least one aromatic ring-containing polymer having a strong absorption in the short wavelength region (particularly, 248 nm or less), which is selected from the group consisting of polymers represented by formulae 1, 2 and 3:

[48] wherein each R₁ is selected from

[50] (R is H or alkyl), eachR2 is selected from hydrogen (-H), hydroxy! (-OH), C₁-Ci₀ alkyl, C₆-Ci₀ aryl, allyl and halogen, R₃ is selected from

[52] and 1 < n< 750;

54 wherein R is selected from

[56] (RisHorallcyl), R₅ is selected from

[57]

[58] and 1 < n < 750; and

(3) [60] wherein RJ, R₂, R₃, R^, R₅ and n are as defined in ϊbrmulae 1 and 1, 1 < m < 750, and

2 < m + n < 1,50O₃ and

[61] (b) an organic solvent

[62] It is preferred that the aromatic ring-containing polymer (a) contains aromatic rings in the skeleton of the polymer. Since the aromatic rings absorb light of short wavelengths (248 nm or less) during lithography, the composition of the present invention can be used to form a hardmask layer that minimizes the reflectivity between a resist and an underlying layer, thus avoiding the formation of an additional antire- flective coating (ARQ.

[63] It is preferred that the aromatic ring-containing polymer has a number of reactive sites (i.e. hydroxyl (-OH) groups) distributed along the backbone chain of the polymer that reacts with a crosslinking component. At this time, the hydroxyl groups react with the adjacent hydroxyl groups or the terminal alkoxy (-OCH₃) groups of the polymer ('self-crosslinkmg'). This self-crosslinking allows the antireflective hardmask composition of the present invention to be cured by baking without the use of an additional crosslinking component.

[64] The curing of the composition according to the present invention may be promoted by crosslinking with a crosslinking component other than the selfcrosslinking. That is, a number of reactive sites (particularly, hydroxyl (-OH) groups) distributed along the backbone of the polymer can be crosslinked with a crosslinking component,

[65] In addition, the antireflective hardmask composition of the present invention lias solution- and film-forming characteristics, which assist in the formation of a layer by a conventional spin-coating technique.

[66] AH the above requirements are met due to the presence of at least one aromatic ring- containing polymer selected from polymer selected from the group consisting of the polymers represented by ϊbrmulae 1, 2 and 3 in the hardmask composition of the present invention.

[67] The aromatic ring-containing polymer preferably has a weight average molecular weight of 1,000 to 30,000 Within this range, the aromatic ring-containing polymer is appropriately soluble in the solvent, rendering the hardmask composition suitable for coating.

[68] The aromatic ring-containing polymer (a) is preferably present in an amount of 1 to 30 parts by weight, based on 100 parts by weight of the organic solvent (b). The reason why the amount of the aromatic ring-containing polymer used is limited within the range defined above is that a desired coating thickness is not attained, Le. it is difficult to accurately regulate a coating thickness.

[69] There is no particular limitation on the kind of the organic solvent (b) so long as the aromatic ring-containing polymer (a) can be sufficiently dissolved in the organic solvent (b). As suitable organic solvents, there may be exemplified propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), cyclohexanone (Anone) and ethyl lactate (EL).

[Z)] The hardmask composition of the present invention may further comprise (c) a crosslinking component that is preferably capable of crosslinking the repeating units of the polymer upon heating. The hardmask composition of the present invention may further comprise (d) an acid or base catalyst that preferably serves to catalyze the crosslinking component (c). It is more preferred that the catalyst (d) be thermally activated.

[71] Any crosslinking component capable of reacting with the hydroxyl groups of the aromatic ring-containing polymer in a manner that can be catalyzed by the acid or base catalyst may be used without any particular limitation in the hardmask composition of the present invention.

[72] Specific examples of suitable crosslinking components for use in the antireflective hardmask composition of the present invention include: etherified amino resins, methylated melamine resins (e.g,, N-methoxymethyl-melamine resins), butylated melamine resins (e.g., N-butoxymethyl-melamine resins), methylated and butylated urea resins (e.g., Cymel U-65 Resin and UFR 80 Resin), glycoluril derivatives (e.g., Powderlink 1174), and 2,6-bis(hydroxymethyl)-/?-cresol.

[73] The Powderlink 1174 is a compound of Ramula 4:

[75] As the crosslinking component, there may be used the bisepoxy compound of formula 5:

[77] Exemplary acid catalysts include organic acids, e.g,, p-toluenesulfonic acid monohydrate. In view of storage stability, a thermal acid generator (TAG) may be used as the acid catalyst. TAG is a compound that generates an acid upon thermal treatment. Examples of preferred TAGs include pyridinium p-toluenesύlfonate, 2,4,4 ,6-tetrabromocyclohexadienol, benzoin tosylate, 2-nitrobenzyl tosylate, and alkyl esters of organic sulfonic acids.

[78] The base catalyst may be selected from ammonium hydroxides represented by NH₄

OH or NR ₄OH (R = alkyl).

[79] Other radiation-sensitive acid catalysts known in the field of resists can also be used so long as they are compatible with the other components of the antireflective composition.

[80] In the hardmask composition of the present invention, the aromatic ring-containing polymer (a) is preferably present in an amount of 1 to 2C% by weight and more preferably 3 to 10% by weight, the organic solvent (b) is preferably present in an amount of 75 to 98.8% by weight, the crosslinking component (c) is preferably present in an amount of Ql to 5% by weight and more preferably Ql to 3% by weight, and the acid or base catalyst (d) is preferably present in an amount of QOOl to Q05% by weight and more preferably QOOl to QQ3% by weight.

[81] When the content of the aromatic ring-containing polymer (a) is outside the range defined above, a desired coating thickness is not attained, Le. it is difficult to accurately regulate a coating thickness.

[82] When th& content of the organic solvent is outside the range defined above, a desired coating thickness is not attained, Le. it is difficult to accurately regulate a coating thickness.

[83] When the content of the crosslinking component is les s than Q 1 % by weight, crosslinking properties may be not exhibited. Meanwhile, when the content of the crosslinking component is greater than 5% by weight, deformation of a pattern profile may be caused and redeposition contamination may occur due to volatile components evolved upon baking.

[84] When the content of the acid or base catalyst is less than QOO 1% by weight, crosslinking properties may be not exhibited. Meanwhile, when the content of the acid or base catalyst exceeds Q05% by weight, the storage stability of the composition may be adversely affected.

[85] The hardmask composition of the present invention may further comprise at least one additive, such as a surfactant.

[86] The present invention also provides a method for patterning an underlying material layer on a substrate by using the hardmask composition. [87] Specifically, the method of the present invention comprises the steps of (a) providing a material layer on a substrate, (b) forming an antireflective hardmask layer using the composition on the material layer, (c) forming a radiation-sensitive imaging layer on the antireflective hardmask layer, (d) patternwise exposing the radiation-sensitive imaging layer to radiation to form a pattern of radiation-exposed regions in the imaging layer, (e) selectively removing portions of the radiation-sensitive imaging layer and the hardmask layer to expose portions of the material layer, and (f) etching the exposed portions of the material layer to pattern the material layer.

[88] The method may further comprise the step of forming a silicon-containing hardmask layer prior to step (c). The method may further comprise the step of forming a bottom antireflective hardmask layer (BARQ on the silicon-containing hardmask layer prior to step (c).

[89] Specifically, the method of the present invention can be carried out in accordance with the following procedure. Erst, a material ( e.g., aluminum or silicon nitride (SN)) to be patterned is applied to a silicon substrate by any technique known in the art, The material may be an, electrically conductive, semi-conductive, magnetic or insulating material. Thereafter, the hardmask composition of the present invention is spin-coated to a thickness of 500 to 8,000 and baked at 100-30CFC for 10 seconds to 10 minutes to form a hardmask layer. Thereafter, a silicon-containing hardmask composition may be spin-coated to a thickness of 500 to 4,000 on the hardmask layer and baked at 100-3 OCPC for 10 seconds to 10 minutes to form a silicon-containing hardmask layer. If needed, a bottom antireflective coating (BARQ may be formed on the silicon- containing hardmask layer.

[90] A radiation- sensitive image layer is formed on the hardmask layer. Light exposure and development are performed to form a pattern on the imaging layer. Dry etching is performed using a gas mixture, such as CHP₃/CF₄, through recessed portions of the patterned imaging layer to transfer the pattern to the silicon-containing hardmask layer. After the dry etching, a gas mixture, such as BC1₃/C1₂, is used to etch the exposed portions of the hardmask layer through the patterned silicon hardmask layer as a mask. As a result, the hardmask layer is patterned.

[91] Dry etching is performed using a gas mixture, such as CHF₃/CF₄, to pattern the material layer on the substrate. Ashing may be performed to remove the remaining material, leaving the patterned material layer only, for example, the removal of the remaining material can be accomplished using oxygen plasma. The method of the present invention can be applied to the fabrication of a semiconductor integrated circuit device.

[92] 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 only and are not intended to limit the scope of the invention.

[93]

Mode for the Invention

[94] [Synthesis Example 1] [95] (Synthesis of terpolymer of 9,9'-bishydroxynaphthylfluorene, 1-naphthol and 9, 10-bismethoxymethylanthracene)

[96] 45Q5g (1.0 mol) of 9,9'-bishydroxynaρhthylfluorene, 144.2g (1.0 mol) of 1-naphthol, 3.1g (Q02 mol) of diethyl sulfate and 350g of propylene glycol monomethyl ether were completely dissolved with stirring in a 3 L three-neck flask equipped with a mechanical agitator and a condenser while maintaining the temperature of the reactor at IGCC. 10 minutes afterthe dissolution, 532.7g of (2.0 mol) of 9,10-bismefhoxymethylanthracene was dropped into the solution, and then the resulting mixture was allowed to react at 12UC for 15 hours. To the reaction mixture was added 2.98g (Q02 mol) of triethanolamine as a neutralizing agent to quench the reaction. After completion of the reaction, a water/methanol mixture was used to remove the acid from the reaction mixture, and methanol was used to remove low- molecular weight compounds containing the oligomers and monomers, yielding the polymer represented by Ibrmula 6 (M _w = 10,000, polydspersity = 2.0, n =≤ 10, m = 9).

[98] [99] [Synthesis Example 2] [100] (Synthesis of terpolymer of 9,9'-bishydroxynaphthylfluorene, 1-hydroxypyrene and 1 ,4-bismethoxymethylbenzene)

[101] The procedure of Synthesis Example 1 was repeated except that 218.3g (1 mol) of 1-hydroxypyrene was added instead of 144.2g of 1-naphthol and 332.9g (2 mol) of 1,4-bismethoxymethylbenzene was added instead of 532.7g of (2.0 mol) of 9,10-bismethoxymethylanthracene, yielding the copolymer of Ibrmula 7:

[IGB] The molecular weight and the polydispersity of the copolymer were measured by gel permeation chromatography (GPQ in tetrahydrofuran. As a result, the copolymer was found to have a molecular weight of 11,000 (n = 10, m = 11) and a polydispersity of 2.2.

[104] [105] [Synthesis Example 3] [106] (Synthesis of terpolymer of 9,9'-bishydroxynaphthylfluorene, phenol and formaldehyde)

[107] The procedure of Synthesis Example 1 was repeated except that 94.1g (1,0 mol) of phenol was added instead of 144.2g of 1-naphthol and ffllg (2 mol) of formaldehyde was ailed instead of 532.7g of (2.0 mol) of 9, 10-bismethoxymethylanthracene, yielding the copolymer of Formula 8:

[109] The molecular weight and the polydispersity of the copolymer were measured by gel permeation chromatography (GPQ in tetrahydrofuran. As a result, the copolymer was found to have a.molecular weight of 10,000 (n = 8, m = 8) and a polydispersity of 1.8,

[HO] [111] [Synthesis Example 4] [112] (Synthesis of copolymer of 9,9'-bishydroxynaphthylfluorene and 1,4-bismethoxymethylbenzene and copolymer of 9,9'-bishydroxyphenylfluorene and 1,4-bismethoxymethylbenzene, and preparation of blend of the copolymers)

[113] 45Q5g (1.0 mol) of 9,9'-bishydroxynaphthylfluorene, 3.1g (Q02 mol) of diethyl sulfate and 25Og of propylene glycol "monomethyl ether were completely dissolved with stirring in a 2 L three-neck flask equipped with a mechanical agitator and a condenser while maintaining the temperature of the reactor at 100¹C. 10 minutes after the dissolution, 166.4g (1.0 mol) of 1,4-bismethoxymethylbenzene was dropped into the solution, and then the resulting mixture was allowed to react at 12CfC for 24 hours. To the reaction mixture was added 2.98g (Q02 mol) of triethanolamine as a neutralizing agent to quench the reaction. After completion of the reaction, a water/ methanol mixture was used to remove the acid from the reaction mixture, and methanol was used to remove low-molecular weight compounds containing the oligomers and monomers, yielding the polymer represented by Ibrmula 9 (M _w = 10,000, polydispersity = 2.3, n = 20).

[115] 393.5g (1.0 mol) of 9,9'-bishydroxyρhenylfluorene, 3.1g (002 mol) of diethyl sulfate and 25Og of propylene glycol monomethyl ether were completely dissolved with stirring in a 2 L three-neck flask equipped with a mechanical agitator and a condenser while maintaining the temperature of the reactor at 100⁰C. 10 minutes after the dissolution, 166.4g of (1.0 mol) of 1,4-bismethoxymethylbenzene was dropped into the solution, and then the resulting mixture was allowed to react at 12CPCfor 15 hours, To the reaction mixture was added 2,98g (Q02 mol) of triethanolamine as a neutralizing agent to quench the reaction. After completion of the reaction, a water/methanol mixture was used to remove the acid from the reaction mixture, and methanol was used to remove low-molecular weight compounds containing the oligomers and monomers, yielding the polymer represented by Iormula 10 (M _w = 10,000, polydispersity = 1.9, n = 22).

[117] [118] The polymers of R>rmulae 9 and 10 were mixed together in a ratio of 9:1 to prepare a blend,

[119] [120] [Examples 1 to 4] [121] Q8g of each of the polymers prepared in Synthesis Examples 1 to 4, Q2g of Powderlink 1174 (Ebrmula 4) as a crosslinker and 2 mg of pyridnium p - toluenesulfonate were dissolved in 9g of propylene glycol mononiethyl ether acetate (PGMEA), and filtered to prepare a sample solution.

[122] Each of the sample solutions prepared in Examples 1 to 4 was spin-coated on a silicon wafer and baked at 200¹C for 60 seconds to form a 4,000A-thick film.

[123] The refractive index (n) and extinction coefficient (k) of the films were measured using an ellipsometer (J. A. Woollam). The results are shown in Table 1.

[124] The data of Table 1 show that the films are suitable for use as antireflective firms at 193nm (ArF) and 248 nm (KrF).

[125] TABLE 1

[126]

Optical properties Cl 93 nrrύ Optical properties ("248 nmi

Sarnple used in the formation of film Refractive Extinction Refractive Extinction index (n) coefficient (k) index (n) coefficient (k)

Example 1 1.47 0.65 1.90 0.20

Example 2 1.43 0,30 2.11 0.28

Example 3 1.44 0.71 1.80 0.06

Example 4 1.43 0.69 1.83 0.07

[127] [Examples 5 to 8]

[128] Each of the sample solutions prepared in Examples 1 to 4 was spin-coated on a silicon wafer covered with silicon nitride and baked at 200¹C for 60 seconds to form a 4,000 A-thick film.

[129] A silicon antireflective coating (ARQ was formed on the film and baked at 240C for 60 seconds. Thereafter, an ArF photoresist (PR) was coated to a thickness of 1,XK) on the silicon ARC, baked at 1 ICPC for 60 seconds, exposed to light using an ArF exposure system (ASML, XT: 1400, NA Q93), and developed with an aqueous solution of TMAH (2.38 wt%) to form a 63-nm line and space pattern. The patterns were observed using a field emission scanning electron microscope (FE-SEM). The patterns were measured for exposure latitude (EL) margin as a function of exposure energy and depth of focus (DoF) margin as a function of the distance from a light source. The results are recorded in Table 2.

[130] TABLE 2 T/KR2007/007059

16

[131]

Pattern properties

Sample used in the formation of film EL margin DoF margin (μm) Profile (Δ mJ/exρosure energy mJ)

Example 5 4 0.25 Cubic

Example 6 4 0.25 Cubic

Example ? 4 0.25 Cubic

Example S 4 0.25 Cubic

[132] [Examples 9 to 12]

[133] Each of the silicon ARCs of the patterned specimens (Examples 5 to 8) was dry- etched using a gas mixture of CHF₃/CF₄ through a photoresist (PR) as a mask. The hardmaslc was dry-etched using a gas mixture OfO₂ZN₂ through the silicon ARC as a mask. Thereafter, the silicon nitrϋe was dry-etched using a gas mixture OfCHF₃ZCF₄ through the hardmask as a mask. O₂ ashing and wet stripping were performed on the remaining portions of the hardmask and the organic material.

[134] Immediately after etching of the hardmask and the silicon nitride, the cross sections of the specimens were observed using an FE-SEM. The results are listed in Table 3.

[135] The etched patterns all showed good profiles without being bowed or tapered. The reason for good etching of the silicon nitride Is believed to be because the hardmasks were sufficiently resistant to the etching gas.

[136] TABLE 3

[137]

Sample used in the Pattern shape after Pattern shape after formation of film etching of hardmask etching of silicon nitride

Example 9 Vertical (Anisotropic) Vertical (Anisotropic)

Example 10 ^"Vertical (Anisotropic) Vertical (Anisotropic)

Example U Vertical (Anisotropic) Vertical (Anisotropic)

Example 12 Vertical (Anisotropic) Vertical (Anisotropic)

[138] As apparent from the above description, the antiretlective hardmask composition of the present invention can be used to form a film having a refractive index and an ab- sorbance suitable for use as an antireflective film in the deep UV (DUV) (e.g., ArF (193 nm) and KrF (248 nm)). Therefore, the antireflective hardmask composition of the present invention exhibits -very high etch selectivity for lithography. In addition, since the antireflective hardmask composition of the present invention is sufficiently resistant to multiple etching, it can be used to form a hardmask having a very good etch profile. Therefore, a good image can be transferred to an underlying layer. Fur- thermore, since the antirefiective hardmask composition of the present invention can minimize the reflectivity between a resist and an underlying layer, it can be used to provide a lithographic structure that has better results in terms of pattern profile and margins.

[139]

Industrial Applicability

[140] Accordingly, the composition of the present invention and the resulting lithographic structure can be used in the fabrication and design of integrated circuit devices. R>r example, the composition of the present invention can be used in the formation of patterned material layer structures, such as metal wirings, holes for contacts and biases, insulating sections (e.g., damascene trenches (DTs) and shallow trench isolation (STT)), and trenches for capacitor structures. It should be appreciated that the present invention is not restricted to any particular lithographic techniques and device structures.

[141]

Claims

[1] An antireflective hardmask composition comprising

(a) at least one aromatic ring-containing polymer selected from the group consisting of polymers represented by Rrmulae 1, 2 and 3:

wherein ea

(R is H or alkyl), each R₂ is selected from hydrogen (-H), hydroxyl (-OH), C₁-Ci₀ alkyl, C₆-Ci₀ ∞yh allyl and halogen, R₃ is selected from

and 1 ≤ n < 750;

4-R₄-R₅H- I In (2) wherein R₄ is selected from

(R is H or alkyl), R₅ is selected from

and 1 < n < 750; and

wherein R₁, R₂, R₃, R₄, Rs and n are as defined in Ibrmulae 1 and 2, 1 <■ m < 750, and2 < m + n < 1,500, and

(b) an organic solvent,

[2] The composition according to claim 1, further comprising (c) a crosslinking component.

[3] The composition according to claim 2, further comprising (d) an acid or base catalyst.

[4] The composition according to claim 3, wherein the composition comprises 1 to

20% by weight of the aromatic ring-containing polymer (a), 75 to 98.8% by weight of the organic solvent Qo), Ql to 5% by weight of the crosslinking component (c), and QOOl to Q05% by weight of the acid or base catalyst (d).

[5] The composition according to claim 1, wherein the aromatic ring-containing polymer has a weight average molecular weight of 1,000 to 30.,00Q

[6] The composition according to claim 1 , further comprising a surfactant.

[7J The composition according to claim 2, wherein the cros slinking component is selected from the group consisting of melamine resins, amino resins, glycoluril compounds, and bisepoxy compounds.

[8] The composition according to claim 3₃ wherein the acid catalyst is selected from the group consisting of p-toluenesulfonic acid monohydrate, pyridinium p - toluenesulfonate, 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, and alkyl esters of organic sulfonic acids.

[9] The composition according to claim 3, wherein the base catalyst is selected from ammonium hydroxides represented by NH₄OH or JSR₊OH (R = alkyl).

[10] A method for patterning a material on a substrate, the method comprisingthe steps of (a) providing a material layer on a substrate, (b) forming an antire- flective hardmask layer using the composition according to claim 1 on the material layer, (c) forming a radiation-sensitive imaging layer on the antirefleetive hardmask layer, (d) patternwise exposing the radiation-sensitive imaging layer to radiation to form a pattern of radiation-exposed regions in the imaging layer, (e) selectively removing portions of the radiation-sensitive imaging layer and the antirefleetive hardmask layer to expose portions of the material layer, and (f) etching the exposed portions of the material layer to pattern the material layer.

[11] The method according to claim 10, further comprising the step of forming a silicon-containing hardmask layer prior to step (c).

[12] The method according to claim 11, further comprising the step of forming a bottom antirefleetive coating (BARQ on the silicon-containing hardmask layer prior to step (c).