WO2008038863A1

WO2008038863A1 - Novel organosilane polymer, hardmask composition for resist underlayer film comprising the organosilane polymer, and process of producing semiconductor integrated circuit device using the hardmask composition

Info

Publication number: WO2008038863A1
Application number: PCT/KR2006/005915
Authority: WO
Inventors: Hui Chan Yoon; Sang Kyun Kim; Sang Hak Lim; Dong Sun Uh; Jong Seob Kim; Chang Il Oh
Original assignee: Cheil Industries Inc
Current assignee: Cheil Industries Inc
Priority date: 2006-09-28
Filing date: 2006-12-31
Publication date: 2008-04-03
Anticipated expiration: 2009-03-28
Also published as: TWI369582B; TW200827928A; KR100760522B1

Abstract

A hardmask composition for processing a resist underlayer film is provided. The hardmask composition comprises: (a) an organosilane polymer prepared by reacting polycondensation products of hydrolysates of compounds represented by Formulae 1, 2 and 3: [RO]3Si-Ar (1) (wherein R is methyl or ethyl and Ar is an aromatic ring-containing functional group), [RO]3Si-H (2) (wherein R is methyl or ethyl), and [RO]3 Si-R' (3) (wherein R is methyl or ethyl and R'is substituted or unsubstituted cyclic or acyclic alkyl) with ethyl vinyl ether of Formula 4: CH2 CHOCH2 CH3 (4) in the presence of an acid catalyst; (b) a solvent; and (c) a crosslinking catalyst.

Description

NOVEL ORGANOSILANE POLYMER, HARDMASK

COMPOSITION FOR RESIST UNDERLA YER FILM

COMPRISING THE ORGANOSILANE POLYMER, AND

PROCESS OF PRODUCING SEMICONDUCTOR INTEGRATED

CIRCUIT DEVICE USING THE HARDMASK COMPOSITION

Technical Field

[1] The present invention relates to a novel organosilane polymer, a hardmask composition for processing a resist underlayer film comprising the organosilane polymer, and a process for producing a semiconductor integrated circuit device using the hardmask composition. More particularly, the present invention relates to a composition for processing a resist underlayer film that exhibits improved storage stability, high pattern reproducibility, good adhesion to a resist, superior resistance to a developing solution (i.e. solvent resistance) used after exposure of the resist, and decreased loss of a film by plasma etching.

[2]

Background Art

[3] For better resolution in most lithographic processes, an antireflective coating (ARC) material is used to minimize the reflectivity between a resist material layer and a substrate. However, the similarity in basic composition between the ARC and the resist material layer results in poor etch selectivity between the ARC material and the patterned resist layer. Accordingly, consumption of portions of the resist layer is inevitable during etching of the ARC after patterning, thus requiring further patterning of the resist layer in the subsequent etching step.

[4] Resist materials used in some lithographic techniques do not provide high resistance to the subsequent etching step to an extent sufficient to effectively transfer a desired pattern to a layer underlying the resist material. A hardmask for a resist underlayer film has been used, for example, in the case when an extremely thin resist material is used, a substrate to be etched is thick, a large etching depth is needed, and/or the use of a particular etchant is required depending on the type of substrate.

[5] The hardmask for a resist underlayer film plays a role as an intermediate layer between a patterned resist and a substrate to be patterned. The hardmask for a resist underlayer film serves to transfer a pattern of the patterned resist to the substrate. Therefore, the hardmask layer for a resist underlayer film must be able to withstand etching required for the transfer of the pattern. [6] For example, a resist pattern is used as a mask to process a substrate, e.g., a silicon oxide film. Miniaturization of circuits has resulted in a reduction of the thickness of resists, making it difficult for the resists to act as masks. As a result, processing of oxide films without any damage is substantially impossible. According to a process to overcome these problems, a resist pattern is transferred to an underlay er film for processing an oxide film, followed by dry etching the oxide film using the pattern- transferred underlay er film as a mask. The underlay er film for processing the oxide film refers to a film formed under an antireflective film to function as an underlayer antireflective film. In this process, since the etching rate of the resist is similar to that of the underlayer film for processing the oxide film, it is necessary to form a mask between the resist and the underlayer film to process the underlayer film, or to form a hardmask with very different etching rates, i.e. high etch selectivity, to process the oxide film. Specifically, an underlayer film for processing an oxide film, a mask for processing the underlayer film (i.e. a hardmask for the resist underlayer film) and a resist are formed sequentially on an oxide film. This multilayer structure is shown in FIG. 1. In this case, the most important requirements of the mask for processing the underlayer film are etch resistance and high etch selectivity with respect to the underlayer for processing the oxide film. In addition, the mask must not be dissolved in a solvent used to form the antireflective film thereon by coating. That is, the mask must have excellent solvent resistance.

[7] Various attempts have been made to meet the above requirements. For example, a polycondensation product of silane compounds represented by R Si(OR) (a = 2, 3 or a 4-a

4) is used as a mask material for processing an underlayer film. However, the largest problem of the silane compounds is that the polycondensation of the silane compounds occurs in a solution state. When the polycondensation product is used to form a coating after storage for a certain time, the desired thickness of the coating is not attained. Further, the polycondensation product is substantially insoluble in solvents because of its too high molecular weight, causing the problem that many defects tend to be generated. That is, in many cases, the polycondensation product is disadvantageous in terms of the storage stability. The polycondensation is induced by silanol groups (Si-OH) present at the ends of the silane compound. To ensure the desired storage stability of the polycondensation product, it is required to limit the number of the silanol groups or to protect the groups with suitable functional groups.

[8]

Disclosure of Invention Technical Problem

[9] 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 organosilane polymer that is used to form a hardmask for a resist underlayer film. [10] It is another object of the present invention to provide a hardmask composition for processing an underlayer film, the composition comprising the organosilane polymer to achieve improved storage stability, high etch selectivity and sufficient resistance to multiple etching. [11] It is another object of the present invention to provide an antireflective hardmask composition that is used to form a good pattern upon processing of a resist due to its excellent ARC effects and allows the pattern to be effectively transferred to a silicon oxide film during subsequent processing. [12] It is another object of the present invention to provide a process for producing a semiconductor integrated circuit device using the hardmask composition. [13] It is yet another object of the present invention to provide a device produced by the process. [14]

Technical Solution [15] In accordance with one aspect of the present invention, there is provided an organosilane polymer prepared by reacting polycondensation products of hydrolysates of compounds represented by Formulae 1, 2 and 3 in the presence of an acid catalyst with ethyl vinyl ether of Formula 4: [16] [RO] Si-Ar (1)

[17] (wherein R is methyl or ethyl and Ar is an aromatic ring-containing functional group);

[18] [RO]₃Si-H (2)

[19] (wherein R is methyl or ethyl); and

[20] [RO]₃Si-R' (3)

[21] (wherein R is methyl or ethyl and R'is substituted or unsubstituted cyclic or acyclic alkyl)

[22] CH₂CHOCH₂CH₃ (4)

[23] The hydrolysates of the compounds of Formulae 1, 2 and 3 may be represented by

Formulae 5, 6 and 7, respectively: [24] ArSi[OH] (5)

[25] (wherein Ar is an aromatic ring-containing functional group);

[26] HSi[OH] (6); and

[27] R⁷Si[OH]₃ (7)

[28] (wherein R'is substituted or unsubstituted cyclic or acyclic alkyl).

[29] The polycondensation products may be represented by Formula 8: [30]

(8)

[31] wherein Ar is an aromatic ring-containing functional group, R'is substituted or un- substituted cyclic or acyclic alkyl, x, y and z satisfy the relations x + y + z = 4, 0.04 < x < 0.80, 0 < y < 1.40 and 1.80 < z < 3.96, and n is from 3 to 500.

[32] The organosilane polymer may be represented by Formula 9: [33]

(9)

[34] wherein Ar is an aromatic ring-containing functional group, R'is substituted or un- substituted cyclic or acyclic alkyl, each Me is a methyl group, x, y and z satisfy the relations x + y + z = 4, 0.04 < x < 0.80, 0 < y < 1.40 and 1.80 < z < 3.96, and n is from 3 and 500.

[35] The acid catalyst may be selected from the group consisting of nitric acid, sulfuric acid, /?-toluenesurfonic acid monohydrate, diethyl sulfate, 2,4,4,6-tetra-bromo-2,5-cyclohexadienone, and alkyl esters of organic sulfonic acids.

[36] The organosilane polymer may be prepared by mixing 1 to 20 parts by weight of the compound of Formula 1, 0 to 35 parts by weight of the compound of Formula 2 and 45 to 99 parts by weight of the compound of Formula 3 with respect to 100 parts by weight of the compounds of Formulae 1, 2 and 3, allowing the mixture to react in the presence of 0.001 to 5 parts by weight of the acid catalyst in 10 to 100 parts by weight of water and 100 to 900 parts by weight of a solvent to obtain poly condensation products, and reacting the polycondensation products with 1 to 200 parts by weight of ethyl vinyl ether of Formula 4.

[37] The solvent may be selected from the group consisting of acetone, tetrahydrofuran, benzene, toluene, diethyl ether, chloroform, dichloromethane, ethyl acetate, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, ethyl lactate, γ-butyrolactone, and mixtures thereof.

[38] In accordance with another aspect of the present invention, there is provided a hardmask composition for processing a resist underlayer film, the composition comprising:

[39] (a) an organosilane polymer prepared by reacting polycondensation products of hy- drolysates of compounds represented by Formulae 1, 2 and 3 in the presence of an acid catalyst with ethyl vinyl ether of Formula 4:

[40] [RO] Si-Ar (1) [41] (wherein R is methyl or ethyl and Ar is an aromatic ring-containing functional group),

[42] [RO]₃Si-H (2) [43] (wherein R is methyl or ethyl), and [44] [RO]₃Si-R' (3) [45] (wherein R is methyl or ethyl and R'is substituted or unsubstituted cyclic or acyclic alkyl)

[46] CH₂CHOCH₂CH₃; (4) [47] (b) a solvent; and [48] (c) a crosslinking catalyst. [49] The hydrolysates of the compounds of Formulae 1, 2 and 3 may be represented by Formulae 5, 6 and 7, respectively:

[50] ArSi[OH] (5) [51] (wherein Ar is an aromatic ring-containing functional group); [52] HSi[OH] (6); and [53] R⁷Si[OH]₃ (7) [54] (wherein R'is substituted or unsubstituted cyclic or acyclic alkyl). [55] The polycondensation products may be represented by Formula 8: [56]

(8)

[57] wherein Ar is an aromatic ring-containing functional group, R'is substituted or un- substituted cyclic or acyclic alkyl, x, y and z satisfy the relations x + y + z = 4, 0.04 < x < 0.80, 0 < y < 1.40 and 1.80 < z < 3.96, and n is from 3 to 500.

[58] The organosilane polymer may be represented by Formula 9: [59]

(9)

[60] wherein Ar is an aromatic ring-containing functional group, R'is substituted or un- substituted cyclic or acyclic alkyl, each Me is a methyl group, x, y and z satisfy the relations x + y + z = 4, 0.04 < x < 0.80, 0 < y < 1.40 and 1.80 < z < 3.96, and n is from 3 and 500.

[61] The acid catalyst may be selected from the group consisting of nitric acid, sulfuric acid, /?-toluenesurfonic acid monohydrate, diethyl sulfate, 2,4,4,6-tetra-bromo-2,5-cyclohexadienone, and alkyl esters of organic sulfonic acids.

[62] The organosilane polymer may be prepared by mixing 1 to 20 parts by weight of the compound of Formula 1, 0 to 35 parts by weight of the compound of Formula 2 and 45 to 99 parts by weight of the compound of Formula 3 with respect to 100 parts by weight of the compounds of Formulae 1, 2 and 3, allowing the mixture to react in the presence of 0.001 to 5 parts by weight of the acid catalyst in 10 to 100 parts by weight of water and 100 to 900 parts by weight of a solvent to obtain poly condensation products, and reacting the polycondensation products with 1 to 200 parts by weight of ethyl vinyl ether of Formula 4.

[63] The solvent may be selected from the group consisting of acetone, tetrahydrofuran, benzene, toluene, diethyl ether, chloroform, dichloromethane, ethyl acetate, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, ethyl lactate, γ-butyrolactone, and mixtures thereof.

[64] The hardmask composition of the present invention may comprise 1 to 50 parts by weight of the organosilane polymer with respect to the total weight (100 parts by weight) of the composition, 50 to 99 parts by weight of the solvent with respect to the total weight (100 parts by weight) of the composition, and 0.0001 to 0.01 parts by weight of the crosslinking catalyst with respect to 100 parts by weight of the organosilane polymer.

[65] The solvent may be selected from the group consisting of acetone, tetrahydrofuran, benzene, toluene, diethyl ether, chloroform, dichloromethane, ethyl acetate, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, ethyl lactate, γ-butyrolactone, and mixtures thereof.

[66] The crosslinking catalyst may be selected from the group consisting of pyridinium

/?-toluenesulfonate, amidosulfobetain-16, (-)-camphor-lO-sulfonic acid ammonium salt, ammonium formate, triethylammonium formate, trimethylammonium formate, tetramethylammonium formate, pyridinium formate, and mixtures thereof.

[67] The hardmask composition of the present invention may further comprise at least one additive selected from crosslinkers, radical stabilizers, and surfactants.

[68] In accordance with another aspect of the present invention, there is provided a process for producing a semiconductor integrated circuit device, the process comprising the steps of (a) providing a material layer on a substrate, (b) forming a hardmask layer composed of an organic material on the material layer, (c) coating the hardmask composition of the present invention on the hardmask layer composed of an organic material to form an antireflective hardmask layer, (d) forming a radiation- sensitive imaging layer on the antireflective hardmask layer, (e) patternwise exposing the imaging layer to radiation to form a pattern of radiation-exposed regions in the imaging layer, (f) selectively removing portions of the radiation-sensitive imaging layer and the antireflective hardmask layer to expose portions of the hardmask layer composed of an organic material, (g) selectively removing portions of the patterned antireflective hardmask layer and the hardmask layer composed of an organic material to expose portions of the material layer, and (h) etching the exposed portions of the material layer to pattern the material layer.

[69] In accordance with still another aspect of the present invention, there is provided a semiconductor integrated circuit device produced by the process.

[70]

Brief Description of the Drawings

[71] FIG. 1 is a cross-sectional view of a multilayer structure comprising an antireflective hardmask layer formed of a hardmask composition of the present invention in a lithographic process for the production of a semiconductor integrated circuit device.

[72]

Best Mode for Carrying Out the Invention [73] The present invention will now be described in more detail.

[74] The present invention provides an organosilane polymer prepared by reacting poly- condensation products of hydrolysates of compounds represented by Formulae 1, 2 and 3 in the presence of an acid catalyst with ethyl vinyl ether of Formula 4:

[75] [RO] Si-Ar (1)

[76] (wherein R is methyl or ethyl and Ar is an aromatic ring-containing functional group);

[77] [RO]₃Si-H (2)

[78] (wherein R is methyl or ethyl); and

[79] [RO]₃Si-R' (3)

[80] (wherein R is methyl or ethyl and R'is substituted or unsubstituted cyclic or acyclic alkyl)

[81] CH CHOCH CH (4)

2 2 3

[82] Specific examples of the compound of Formula 1 include the following compounds

(Ia):

(Ia)

[84]

[85] wherein each Me represents a methyl group and each R represents a methyl or ethyl group. [86] Specific examples of the compound of Formula 3 include the following compounds (3a): [87]

[88]

[89]

Me

0"^Si(OR)₃

H₂

(3a)

[90] [91] wherein each Me represents a methyl group and each R represents a methyl or ethyl group.

[92] The organosilane polymer of the present invention may be prepared by mixing 1 to 20 parts by weight of the compound of Formula 1, 0 to 35 parts by weight of the compound of Formula 2 and 45 to 99 parts by weight of the compound of Formula 3 with respect to 100 parts by weight of the compounds of Formulae 1, 2 and 3, allowing the mixture to react in the presence of 0.001 to 5 parts by weight of an acid catalyst in 10 to 100 parts by weight of water and 100 to 900 parts by weight of a solvent to obtain a mixture of hydrolysates of the respective compounds, polycondensing the hy- drolysates without purification to obtain a mixture of poly condensation products of the respective hydrolysates, and reacting the poly condensation products with 1 to 200 parts by weight of ethyl vinyl ether of Formula 4.

[93] The acid catalyst is preferably selected from the group consisting of nitric acid, sulfuric acid, /?-toluenesurfonic acid monohydrate, diethyl sulfate, 2,4,4,6-tetra-bromo-2,5-cyclohexadienone, and alkyl esters of organic sulfonic acids. The hydrolysis reactions can be suitably controlled by varying the kind, the amount and the addition mode of the acid catalyst. Further, the acid catalyst added for the hydrolysis reactions can also be reused as a catalyst for the polycondensation reactions. In the formation reactions of the organosilane polymer, the acid catalyst may be used in an amount of 0.001 and 5 parts by weight. The use of the acid catalyst in an amount smaller than 0.001 parts by weight remarkably slows down the reaction rates, while the use of the acid catalyst in an amount larger than 5 parts by weight causes an excessive increase in the reaction rates, making it impossible to prepare poly condensation products having a desired molecular weight.

[94] The solvent may be selected from the group consisting of acetone, tetrahydrofuran, benzene, toluene, diethyl ether, chloroform, dichloromethane, ethyl acetate, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, ethyl lactate, γ-butyrolactone, and mixtures thereof.

[95] The hydrolysates of the compounds of Formulae 1, 2 and 3 may be represented by Formulae 5, 6 and 7, respectively:

[96] ArSi[OH]₃ (5)

[97] (wherein Ar is an aromatic ring-containing functional group);

[98] HSi[OH]₃ (6); and

[99] R'Si[OH] (7)

[100] (wherein R'is substituted or unsubstituted cyclic or acyclic alkyl).

[101] As the polycondensation products, there may be exemplified those represented by Formula 8:

[102]

(8)

[103] wherein Ar is an aromatic ring-containing functional group, R'is substituted or unsubstituted cyclic or acyclic alkyl, x, y and z satisfy the relations x + y + z = 4, 0.04 < x < 0.80, 0 < y < 1.40 and 1.80 < z < 3.96, and n is from 3 to 500.

[104] In Formula 8, Ar, H and R'represent functional groups bonded to respective Si atoms. The number of the respective functional groups is as defined in Formula 8. [105] The organosilane polymer may be prepared by the reaction of the polycondensation products of Formula 8 and ethyl vinyl ether of Formula 4.

[106] The organosilane polymer may be represented by Formula 9: [107]

(9)

[108] wherein Ar is an aromatic ring-containing functional group, R'is substituted or un- substituted cyclic or acyclic alkyl, each Me is a methyl group, x, y and z satisfy the relations x + y + z = 4, 0.04 < x < 0.80, 0 < y < 1.40 and 1.80 < z < 3.96, and n is from 3 and 500.

[109] In Formula 9, Ar, H and R'represent functional groups bonded to respective Si atoms. The number of the respective functional groups is as defined in Formula 9.

[110] The present invention also provides a hardmask composition for processing a resist underlay er film, comprising:

[111] (a) an organosilane polymer prepared by reacting poly condensation products of hy- drolysates of compounds represented by Formulae 1, 2 and 3 in the presence of an acid catalyst with ethyl vinyl ether of Formula 4:

[112] [RO]₃Si-Ar (1)

[113] (wherein R is methyl or ethyl and Ar is an aromatic ring-containing functional group),

[114] [RO] Si-H (2)

[115] (wherein R is methyl or ethyl), and

[116] [RO] Si-R' (3)

[117] (wherein R is methyl or ethyl and R'is substituted or unsubstituted cyclic or acyclic alkyl)

[118] CH₂CHOCH₂CH₃; (4)

[119] (b) a solvent; and

[120] (c) a crosslinking catalyst.

[121] The organosilane polymer of the present invention may be prepared by mixing 1 to

20 parts by weight of the compound of Formula 1, 0 to 35 parts by weight of the compound of Formula 2 and 45 to 99 parts by weight of the compound of Formula 3 with respect to 100 parts by weight of the compounds of Formulae 1, 2 and 3, allowing the mixture to react in the presence of 0.001 to 5 parts by weight of an acid catalyst in 10 to 100 parts by weight of water and 100 to 900 parts by weight of a solvent to obtain a mixture of hydrolysates of the respective compounds, polycondensing the hy- drolysates without purification to obtain a mixture of poly condensation products of the respective hydrolysates, and reacting the poly condensation products with 1 to 200 parts by weight of ethyl vinyl ether of Formula 4.

[122] The acid catalyst is preferably selected from the group consisting of nitric acid, sulfuric acid, /?-toluenesurfonic acid monohydrate, diethyl sulfate, 2,4,4,6-tetra-bromo-2,5-cyclohexadienone, and alkyl esters of organic sulfonic acids. The hydrolysis reactions can be suitably controlled by varying the kind, the amount and the addition mode of the acid catalyst. Further, the acid catalyst added for the hydrolysis reactions can also be reused as a catalyst for the polycondensation reactions. In the formation reactions of the organosilane polymer, the acid catalyst may be used in an amount of 0.001 and 5 parts by weight. The use of the acid catalyst in an amount smaller than 0.001 parts by weight remarkably slows down the reaction rates, while the use of the acid catalyst in an amount larger than 5 parts by weight causes an excessive increase in the reaction rates, making it impossible to prepare polycondensation products having a desired molecular weight.

[123] The solvent may be selected from the group consisting of acetone, tetrahydrofuran, benzene, toluene, diethyl ether, chloroform, dichloromethane, ethyl acetate, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, ethyl lactate, γ-butyrolactone, and mixtures thereof.

[124] The hydrolysates of the compounds of Formulae 1, 2 and 3 may be represented by

Formulae 5, 6 and 7, respectively:

[125] ArSi[OH] (5)

[126] (wherein Ar is an aromatic ring-containing functional group);

[127] HSi[OH] (6); and

[128] R⁷Si[OH]₃ (7)

[129] (wherein R'is substituted or unsubstituted cyclic or acyclic alkyl).

[130] As the polycondensation products, there may be exemplified those represented by

Formula 8:

[131]

(8) [132] wherein Ar is an aromatic ring-containing functional group, R'is substituted or un- substituted cyclic or acyclic alkyl, x, y and z satisfy the relations x + y + z = 4, 0.04 < x < 0.80, 0 < y < 1.40 and 1.80 < z < 3.96, and n is from 3 to 500.

[133] In Formula 8, Ar, H and R'represent functional groups bonded to respective Si atoms. The number of the respective functional groups is as defined in Formula 8. [134] The organosilane polymer may be prepared by the reaction of the polycondensation products of Formula 8 and ethyl vinyl ether of Formula 4.

[135] The organosilane polymer may be represented by Formula 9: [136]

(9)

[137] wherein Ar is an aromatic ring-containing functional group, R'is substituted or un- substituted cyclic or acyclic alkyl, each Me is a methyl group, x, y and z satisfy the relations x + y + z = 4, 0.04 < x < 0.80, 0 < y < 1.40 and 1.80 < z < 3.96, and n is from 3 and 500.

[138] In Formula 9, Ar, H and R'represent functional groups bonded to respective Si atoms. The number of the respective functional groups is as defined in Formula 9. [139] Taking advantage of the ability of the aromatic group included in the compound of Formula 1 to absorb UV light, the hardmask composition of the present invention exhibits excellent antireflective properties due to high UV absorbance of the organosilane polymer. At the same time, the hardmask composition of the present invention has desired absorbance and refractive index in a particular wavelength region by controlling the number of the aromatic groups in the organosilane polymer.

[140] It is preferable to use the compound of Formula 1 in an amount of 1 to 20 parts by weight, based on the total weight (100 parts by weight) of the compounds of Formulae 1, 2 and 3. The use of the compound of Formula 1 in an amount of less than 1 part by weight causes low absorbance of the hardmask composition. Meanwhile, the use of the compound of Formula 1 in an amount of more than 20 parts by weight causes a problem in that sufficient etch selectivity cannot be ensured due to low Si content. Suitable antireflective properties can be attained by controlling the relative amount of the compound of Formula 1. For example, when the compound of Formula 1 has a phenyl group as the aromatic group and is used in an amount of 10 parts by weight, the hardmask composition has an absorbance (k) of about 0.2.

[141] On the other hand, an increase in the relative amount of the compound of Formula 2 used leads to an increase in the content of Si in the hardmask composition of the present invention. This variation in the Si content of the hardmask composition can impart suitable etch selectivity between the hardmask composition of the present invention and both of an overlying photoresist layer and an underlying hardmask layer composed of an organic material. It is preferred to use the compound of Formula 2 in an amount not greater than 35 parts by weight, based on the total weight (100 parts by weight) of the compounds of Formulae 1, 2 and 3. When the compound of Formula 2 is used in an amount exceeding 35 parts by weight, the storage stability of the hardmask composition may be impaired due to the labile Si-H bonds.

[142] An increase in the relative amount of the compound of Formula 3 used may lead to an improvement in the storage stability of the hardmask composition. It is preferred to use the compound of Formula 3 in an amount of 45 to 99 parts by weight, based on the total weight (100 parts by weight) of the compounds of Formulae 1, 2 and 3. The use of the compound of Formula 3 in an amount of less than 45 parts by weight may cause poor storage stability of the hardmask composition, and meanwhile, the use of the compound of Formula 3 in an amount exceeding 99 parts by weight may cause the problem that the absorbance of the hardmask composition is lowered.

[143] Ethyl vinyl ether of Formula 4 reacts with Si-OH groups to form Si-OCH(CH

3

)OCH CH groups and serves to protect Si-OH groups, thus ensuring the stability of the final composition. In the meanwhile, the Si-OCH(CH )OCH CH groups are readily converted to Si-OH groups at high temperature in the presence of a crosslinking catalyst, as will hereinafter be described. When the hardmask composition is coated and heated during subsequent processing, Si-OH groups are recovered and crosslinked with one another. This crosslinking leads to the formation of a rigid film. It is preferred to use the compound of Formula 4 in an amount of 1 to 200 parts by weight, based on 100 parts by weight of the compounds of Formulae 1, 2 and 3. When the compound of Formula 4 is used in an amount of less than 1 part by weight, no improvement in the storage stability of the hardmask composition can be expected. Meanwhile, all Si-OH groups already react with the compound of Formula 4 in an amount not greater than 200 parts by weight, thus making it impossible to expect a further improvement in the storage stability of the hardmask composition. [144] The organosilane polymer is preferably present in an amount of 1 to 50 parts by weight and more preferably 1 to 30 parts by weight, based on the total weight (100 parts by weight) of the hardmask composition. When the content of the organosilane polymer is outside the preferable range, the coatability of the hardmask composition becomes poor.

[145] Examples of the solvent used in the hardmask composition of the present invention include acetone, tetrahydrofuran, benzene, toluene, diethyl ether, chloroform, dichloromethane, ethyl acetate, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, ethyl lactate, γ- butyrolactone, and mixtures thereof. The solvent may be the same as or different from the solvent used for the formation reactions of the organosilane polymer. The solvent may be used in an amount of 50 to 99 parts by weight, based on the total weight (100 parts by weight) of the hardmask composition. When the amount of the solvent used is outside the range defined above, the coatability of the hardmask composition becomes poor.

[146] Examples of suitable crosslinking catalysts include: sulfonic acid salts of organic bases, such as pyridinium /?-toluenesulfonate, amidosulfobetain-16 and (-)-camphor-lO-sulfonic acid ammonium salt; formic acid salts of organic bases, such as ammonium formate, triethylammonium formate, trimethylammonium formate, tetramethylammonium formate and pyridinium formate; and acetic acid salts of organic bases, such as ammonium acetate, triethylammonium acetate, trimethylammonium acetate, tetramethylammonium acetate and pyridinium acetate, and mixtures thereof.

[147] These crosslinking catalyst compounds play a role in promoting the crosslinking of the organosilane polymer to improve the etch resistance and solvent resistance of the hardmask composition. The crosslinking catalyst compound is preferably used in an amount of 0.0001 to 0.01 parts by weight, based on 100 parts by weight of the organosilane polymer. Below 0.0001 parts by weight, the above effects cannot be expected. Above 0.01 parts by weight, the storage stability of the hardmask composition is insufficient.

[148] If necessary, the hardmask composition of the present invention may further comprise at least one additive selected from crosslinkers, radical stabilizers, and surfactants.

[149] The present invention also provides a process for producing a semiconductor integrated circuit device, the process comprising the steps of (a) providing a material layer on a substrate, (b) forming a first hardmask layer composed of an organic material on the material layer, (c) coating the hardmask composition of the present invention on the first hardmask layer to form a second hardmask layer, (d) forming a radiation-sensitive imaging layer on the second hardmask layer, (e) patternwise exposing the imaging layer to radiation to form a pattern of radiation-exposed regions in the imaging layer, (f) selectively removing portions of the radiation-sensitive imaging layer and the second hardmask layer to expose portions of the first hardmask layer, (g) selectively removing portions of the patterned second hardmask layer and the first hardmask layer to expose portions of the material layer, and (h) etching the exposed portions of the material layer to pattern the material layer.

[150] The present invention also provides a semiconductor integrated circuit device produced by the process.

[151]

Mode for the Invention

[152] 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 to be construed as limiting the scope of the invention.

[153]

[154] EXAMPLES

[155] [Comparative Example 1]

[156] 1 ,75Og of methyltrimethoxysilane, 34Og of phenyltrimethoxysilane and 313g of trimethoxysilane were dissolved in 5,600g of propylene glycol methyl ether acetate (PGMEA) in a 10-liter four- neck flask equipped with a mechanical agitator, a condenser, a dropping funnel and a nitrogen introduction tube, and then 925g of an aqueous nitric acid solution (1,000 ppm) was added thereto. After the resulting mixture was allowed to react at 6O⁰C for one hour, the formed methanol was removed under reduced pressure. The reaction was continued for one week while maintaining a reaction temperature of 5O⁰C. After completion of the reaction, hexane was added to the reaction mixture to precipitate the polymer of Formula 10:

[157]

(10)

[158] lOOg of PGMEA and lOOg of ethyl lactate were added to 4.Og of the polymer to prepare a dilute solution of the polymer. The resulting solution was spin-coated on a silicon wafer, followed by baking at 24O⁰C for 60 seconds to form a 500A thick film. [159]

[160] [Example 1]

[161] 1 ,75Og of methyltrimethoxysilane, 34Og of phenyltrimethoxysilane and 313g of trimethoxysilane were dissolved in 5,600g of PGMEA in a 10-liter four-neck flask equipped with a mechanical agitator, a condenser, a dropping funnel and a nitrogen introduction tube, and then 925g of an aqueous nitric acid solution (1,000 ppm) was added thereto. The resulting mixture was allowed to react at 6O⁰C for one hour. Thereafter, the formed methanol was removed under reduced pressure. The reaction was continued for one week while maintaining a reaction temperature of 5O⁰C. After the reaction temperature was lowered to 25⁰C, 185g of ethyl vinyl ether was added. The resulting mixture was allowed to react at room temperature for 18 hours. After completion of the reaction, hexane was added to the reaction mixture to precipitate the polymer of Formula 11 :

[162]

[163] lOOg of PGMEA and lOOg of ethyl lactate were added to 4.Og of the polymer to prepare a dilute solution of the polymer. To the dilute solution was added 0.04g of pyridinium/?-toluenesulfonate. The resulting solution was spin-coated on a silicon wafer, followed by baking at 24O⁰C for 60 seconds to form a 500A thick film.

[164] [165] [Experimental Example 1] [166] The solutions prepared in Comparative Example 1 and Example 1 were tested for stability during storage. Each of the solutions was stored at 4O⁰C. At intervals of 10 days, the state of the solution was observed and the thickness of the film after coating of the solution was measured. The results are shown in Table 1.

[167] Table 1

After 10 days After 20 days After 30 days

Sample Normalized _^, , Normalized „. , Normalized „. .

. , , _t Thickness . . . . Thickness , , , _^ Thickness molecular weight molecular weight molecular weight

Comparative 1 1 Poor

512 A 1 8 532 A Particles observed Example 1 LOdtmg

Example 1 1 0 500 A 1 0 502 A 1 0 503 A

[168] [169] The normalized molecular weight as shown in Table 1 refers to a value obtained by dividing the molecular weight of the corresponding polymer measured after the indicated time of storage by the molecular weight of the polymer measured immediately after the preparation of the polymer. An increase in the molecular weight of the polymer prepared in Comparative Example 1 after the indicated time intervals of storage was observed, indicating the occurrence of condensation between the silane compounds present within the solution prepared in Comparative Example 1. In contrast, the molecular weight of the polymer prepared in Example 1 was maintained even after the passage of the crosslinking time, indicating improved storage stability of the solution.

[170]

[171] [Experimental Example 2]

[172] The refractive index (n) and extinction coefficient (k) of the films formed in

Comparative Example 1 and Example 1 were measured using an Ellipsometer (J. A. Woollam). The results are shown in Table 2.

[173] Table 2

Optical properties (193 run) Sample used in the formation of film

Refractive index (n) Extinction coefficient (k)

Comparative Example 1 1.71 0.23

Example 1 1.78 0.23

[174]

[175] As can be seen from Table 2, the films formed in Comparative Example 1 and

Example 1 showed good optical properties at an exposure light source of 193 nm. The protection of Si-OH groups with ethyl vinyl ether of Formula 4 in the polymer prepared in Example 1 could be confirmed to have no bad influence on the optical properties of the mask.

[176]

[177] [Experimental Example 3]

[178] An ArF photoresist was coated on each of the films formed in Comparative

Example 1 and Example 1, baked at 11O⁰C for 60 seconds, exposed to light using an ArF exposure system (ASML 1250, FN70 5.0 active, NA 0.82), and developed with an aqueous solution of TMAH (2.38 wt%) to form an 80-nm line and space pattern. The pattern was 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 3.

[179] Table 3 Sample used in the Pattern Characteristics formatⁱon of film _{£L margm} (_Δmj/_eχposure energy mJ) DoF margin (μm) Comparative Example 1 0 2 0 2

Example 1 0 2 0 2

[180]

[181] The patterns all showed good photoprofile. From these results, it could be confirmed that the protection of Si-OH groups with ethyl vinyl ether of Formula 4 in the polymer prepared in Example 1 did not adversely affect the photoprofile of the photoresist. [182]

[183] [Experimental Example 4]

[184] The patterned specimens obtained in Experimental Example 3 were sequentially dry-etched using a CF plasma, an O plasma and a CF plasma. The remaining organic x 2 x materials were completely removed using O , and the cross sections of the etched specimens were observed using an FE-SEM. The results are listed in Table 4. [185] Table 4

Sample used in the formation of film Pattern shape after etching

Comparative Example 1 Vertical

Example 1 Vertical

[186]

[187] The specimens all showed good etch characteristics. These results reveal that the protection of Si-OH groups with ethyl vinyl ether of Formula 4 in the polymer prepared in Example 1 had no bad influence on the etch resistance, etch selectivity and etch profile of the mask.

[188]

Industrial Applicability

[189] The present invention provides a hardmask composition for processing a resist underlayer film that does not adversely affect the etch resistance, etch selectivity, etch profile, optical properties and photoprofile of a mask. In addition, the hardmask composition of the present invention is highly stable during storage.

Claims

[1] An organosilane polymer prepared by reacting polycondensation products of hy- drolysates of compounds represented by Formulae 1, 2 and 3 in the presence of an acid catalyst with ethyl vinyl ether of Formula 4: [RO]₃Si-Ar (1)

(wherein R is methyl or ethyl and Ar is an aromatic ring-containing functional group); [RO]₃Si-H (2)

(wherein R is methyl or ethyl); and [RO] Si-R' (3)

(wherein R is methyl or ethyl and R'is substituted or unsubstituted cyclic or acyclic alkyl) CH CHOCH CH (4)

2 2 3

[2] The organosilane polymer according to claim 1, wherein the hydrolysates of the compounds of Formulae 1, 2 and 3 are represented by Formulae 5, 6 and 7, respectively: ArSi[OH]₃ (5)

(wherein Ar is an aromatic ring-containing functional group); HSi[OH]₃ (6); and R'Si[0H] (7) (wherein R'is substituted or unsubstituted cyclic or acyclic alkyl).

[3] The organosilane polymer according to claim 1, wherein the polycondensation products are those represented by Formula 8:

(8) wherein Ar is an aromatic ring-containing functional group, R'is substituted or unsubstituted cyclic or acyclic alkyl, x, y and z satisfy the relations x + y + z = 4, 0.04 < x < 0.80, 0 < y < 1.40 and 1.80 < z < 3.96, and n is from 3 to 500.

[4] The organosilane polymer according to claim 1, wherein the organosilane polymer is represented by Formula 9:

(9) wherein Ar is an aromatic ring-containing functional group, R'is substituted or unsubstituted cyclic or acyclic alkyl, each Me is a methyl group, x, y and z satisfy the relations x + y + z = 4, 0.04 < x < 0.80, 0 < y < 1.40 and 1.80 < z < 3.96, and n is from 3 and 500.

[5] The organosilane polymer according to claim 1, wherein the acid catalyst is selected from the group consisting of nitric acid, sulfuric acid, /?-toluenesulfonic acid monohydrate, diethyl sulfate, 2,4,4,6-tetra-bromo-2,5-cyclohexadienone, and alkyl esters of organic sulfonic acids.

[6] The organosilane polymer according to claim 1, wherein the organosilane polymer is prepared by mixing 1 to 20 parts by weight of the compound of Formula 1, 0 to 35 parts by weight of the compound of Formula 2 and 45 to 99 parts by weight of the compound of Formula 3 with respect to 100 parts by weight of the compounds of Formulae 1, 2 and 3, allowing the mixture to react in the presence of 0.001 to 5 parts by weight of the acid catalyst in 10 to 100 parts by weight of water and 100 to 900 parts by weight of a solvent to obtain poly- condensation products, and reacting the poly condensation products with 1 to 200 parts by weight of ethyl vinyl ether of Formula 4.

[7] The organosilane polymer according to claim 6, wherein the solvent is selected from the group consisting of acetone, tetrahydrofuran, benzene, toluene, diethyl ether, chloroform, dichloromethane, ethyl acetate, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, ethyl lactate, γ-butyrolactone, and mixtures thereof.

[8] A hardmask composition for processing a resist underlayer film, the composition comprising:

(a) an organosilane polymer prepared by reacting polycondensation products of hydrolysates of compounds represented by Formulae 1, 2 and 3 in the presence of an acid catalyst with ethyl vinyl ether of Formula 4: [RO] Si-Ar (1)

(wherein R is methyl or ethyl and Ar is an aromatic ring-containing functional group),

[RO]₃Si-H (2)

(wherein R is methyl or ethyl), and

[RO]₃Si-R' (3)

(wherein R is methyl or ethyl and R'is substituted or unsubstituted cyclic or acyclic alkyl)

CH CHOCH CH ; (4)

2 2 3

(b) a solvent; and

(c) a crosslinking catalyst.

[9] The hardmask composition according to claim 8, wherein the hydrolysates of the compounds of Formulae 1, 2 and 3 are represented by Formulae 5, 6 and 7, respectively: ArSi[OH]₃ (5)

(wherein Ar is an aromatic ring-containing functional group); HSi[OH]₃ (6); and R⁷Si[OH]₃ (7)

(wherein R'is substituted or unsubstituted cyclic or acyclic alkyl).

[10] The hardmask composition according to claim 8, wherein the polycondensation products are those represented by Formula 8:

[H] The hardmask composition according to claim 8, wherein the organosilane polymer is represented by Formula 9:

[12] The hardmask composition according to claim 8, wherein the acid catalyst is selected from the group consisting of nitric acid, sulfuric acid, /?-toluenesulfonic acid monohydrate, diethyl sulfate, 2,4,4,6-tetra-bromo-2,5-cyclohexadienone, and alkyl esters of organic sulfonic acids.

[13] The hardmask composition according to claim 8, wherein the organosilane polymer is prepared by mixing 1 to 20 parts by weight of the compound of Formula 1, 0 to 35 parts by weight of the compound of Formula 2 and 45 to 99 parts by weight of the compound of Formula 3 with respect to 100 parts by weight of the compounds of Formulae 1, 2 and 3, allowing the mixture to react in the presence of 0.001 to 5 parts by weight of the acid catalyst in 10 to 100 parts by weight of water and 100 to 900 parts by weight of a solvent to obtain poly- condensation products, and reacting the poly condensation products with 1 to 200 parts by weight of ethyl vinyl ether of Formula 4.

[14] The hardmask composition according to claim 13, wherein the solvent is selected from the group consisting of acetone, tetrahydrofuran, benzene, toluene, diethyl ether, chloroform, dichloromethane, ethyl acetate, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, ethyl lactate, γ-butyrolactone, and mixtures thereof.

[15] The hardmask composition according to claim 8, wherein the hardmask composition comprises 1 to 50 parts by weight of the organosilane polymer with respect to the total weight (100 parts by weight) of the composition, 50 to 99 parts by weight of the solvent with respect to the total weight (100 parts by weight) of the composition, and 0.0001 to 0.01 parts by weight of the crosslinking catalyst with respect to 100 parts by weight of the organosilane polymer.

[16] The hardmask composition according to claim 8, wherein the solvent is selected from the group consisting of acetone, tetrahydrofuran, benzene, toluene, diethyl ether, chloroform, dichloromethane, ethyl acetate, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, ethyl lactate, γ-butyrolactone, and mixtures thereof.

[17] The hardmask composition according to claim 8, wherein the crosslinking catalyst is selected from the group consisting of pyridinium/?-toluenesulfonate, amidosulfobetain-16, (-)-camphor-lO-sulfonic acid ammonium salt, ammonium formate, triethylammonium formate, trimethylammonium formate, tetramethy- lammonium formate, pyridinium formate and mixtures thereof.

[18] The hardmask composition according to claim 8, further comprising at least one additive selected from crosslinkers, radical stabilizers, and surfactants.

[19] A process for producing a semiconductor integrated circuit device, the process comprising the steps of:

(a) providing a material layer on a substrate;

(b) forming a hardmask layer composed of an organic material on the material layer;

(c) coating the hardmask composition according to any one of claims 8 to 18 on the hardmask layer composed of an organic material to form an antireflective hardmask layer;

(d) forming a radiation-sensitive imaging layer on the antireflective hardmask layer;

(e) patternwise exposing the imaging layer to radiation to form a pattern of radiation-exposed regions in the imaging layer;

(f) selectively removing portions of the radiation-sensitive imaging layer and the antireflective hardmask layer to expose portions of the hardmask layer composed of an organic material;

(g) selectively removing portions of the patterned antireflective hardmask layer and the hardmask layer composed of an organic material to expose portions of the material layer; and

(h) etching the exposed portions of the material layer to pattern the material layer.

[20] A semiconductor integrated circuit device produced by the process according to claim 19.