Antireflective polymers and hardmask compositions comprising the same

Abstract

The present disclosure relates to antireflective polymers useful in photolithography having antireflective coating properties, and hardmask compositions comprising the same. The antireflective polymers exhibit strong absorption in the ultraviolet (UV) wavelength range and excellent etch resistance.

Description

Technical Field

[0001] This disclosure relates to antireflective polymers with antireflective coating properties that can be used in photolithography, and hard mask compositions comprising said antireflective polymers. More specifically, this disclosure relates to polymers exhibiting strong absorption and excellent etch resistance in the ultraviolet (UV) wavelength range, and hard mask compositions comprising said polymers. Background Technology

[0002] With the semiconductor industry's ever-increasing demand for finer processes, efficient lithography is becoming crucial for achieving such ultra-fine technology. In particular, there is a growing need for new materials for the hard mask process, which is essential for the etching stage.

[0003] Typically, a hard mask layer serves as an intermediate layer that transfers the fine pattern of photoresist to the underlying substrate layer through a selective etching process. Therefore, the hard mask layer needs to possess properties such as chemical resistance, heat resistance, and etch resistance to withstand multiple etching processes.

[0004] Meanwhile, conventional hard mask layers employ amorphous carbon layers (ACLs) formed through chemical vapor deposition (CVD). However, this method has several drawbacks, including high equipment capital expenditure, particle generation during the process, and photo-alignment problems due to the opacity of the film, making it very inconvenient to use.

[0005] Recently, spin-on hard mask (SOH) technology has been introduced, which uses a spin-on coating method to form layers instead of CVD. Spin-on coating uses solvent-soluble organic polymer materials to form the hard mask composition. In this case, the most critical requirement is to form an organic polymer coating film that also exhibits high etch resistance.

[0006] However, such organic hard mask layers require a balance between two essential properties: solubility and etch resistance. Therefore, a hard mask composition that meets both criteria is needed.

[0007] Recently, materials have been introduced to address these needs for organic hard masks in semiconductor lithography (e.g., Korean Patent Publication Nos. 10-2009-0120827, 10-2008-0107210, and WO 2013100365 A1). These materials utilize polymers with suitable molecular weights synthesized from hydroxypyrene using conventional phenolic resin production methods.

[0008] However, with the recent miniaturization of semiconductor lithography processes, these organic hard mask materials have reached a stage where they cannot fully perform their function as masks due to insufficient etch selectivity compared to conventional inorganic hard mask materials.

[0009] Therefore, there is an urgent need to introduce organic hard mask materials that are more optimized for the etching process. Summary of the Invention

[0010] To address the aforementioned needs, this disclosure aims to provide a novel polymer comprising an aromatic structural unit having one or more hydroxyl groups, as represented by the following chemical formula 1.

[0011] [Chemical Formula 1]

[0012]

[0013] In Formula 1, the Ar group is a C6-C30 aryl or a C6-C30 heteroaryl, wherein the C6-C30 aryl or C6-C30 heteroaryl may be substituted with a hydroxyl group, a halogen group, an alkyl group, or an alkoxy group.

[0014] Furthermore, the Ar group in Formula 1 is an aromatic aryl or heteroaryl compound capable of forming a condensation polymer with a phenyl or naphthyl aldehyde compound having one or more hydroxyl groups.

[0015] In this formula, 'x' is in the range of 0 to 2, and 'y' is 0 or 1.

[0016] Additionally, 'n' can be in the range of 5 to 100.

[0017] Furthermore, this disclosure aims to provide a polymer for hard masks and a composition comprising said polymer, which exhibit excellent polymer solubility, high etch selectivity, and sufficient tolerance to multiple etch processes.

[0018] Furthermore, this disclosure aims to provide a polymer for hard masks and a composition comprising said polymer, which can be used in photolithography by minimizing the reflectivity between the resist and the substrate.

[0019] According to this disclosure, a novel polymer may consist solely of aromatic structural units having one or more hydroxyl groups, as represented by the following chemical formula 1, wherein the Ar group in chemical formula 1 is a group composed of only a single type of structural unit:

[0020] [Chemical Formula 1]

[0021]

[0022] The Ar group is a C6-C30 aryl or a C6-C30 heteroaryl, wherein the C6-C30 aryl or C6-C30 heteroaryl may optionally be substituted by the following groups: hydroxyl, halogen group, alkyl, alkoxy or amine group having a substituent;

[0023] The Ar group in Formula 1 is an aromatic aryl or heteroaryl compound capable of forming a condensation polymer with a phenyl or naphthyl aldehyde compound having one or more hydroxyl groups;

[0024] 'x' is in the range of 0 to 2, and 'y' is 0 or 1;

[0025] 'n' is between 5 and 100; and

[0026] The weight-average molecular weight (Mw) of the polymer is in the range of 1,000 to 30,000.

[0027] According to this disclosure, an anti-reflective hard mask composition may comprise:

[0028] (a) the aforementioned novel polymer or blends thereof; and

[0029] (b) Organic solvents.

[0030] The antireflective hard mask composition may also include a crosslinking agent component and an acid catalyst.

[0031] According to this disclosure, a polymer comprising an aromatic structural unit (the aromatic structural unit being formed by the condensation polymerization of a phenyl or naphthyl aldehyde having one or more hydroxyl groups with an aryl or heteroaryl compound) and a hard mask composition comprising the polymer have a structure with a very high carbon content. This structure is highly advantageous for etch resistance and also exhibits excellent polymer solubility, which is very beneficial for forming uniform thin films.

[0032] Therefore, the polymers according to this disclosure and the hard mask compositions comprising the polymers have higher etch selectivity and sufficient tolerance to multiple etch processes compared to conventional organic hard masks, thereby providing lithographic structures with better pattern evaluation results.

[0033] Specifically, during film formation, the hard mask composition based on the polymer according to embodiments of this disclosure has a refractive index and absorbance within a range suitable for use as an antireflective coating in deep UV regions (e.g., ArF (193 nm) and KrF (248 nm)). This enables minimizing reflectivity between the resist and the substrate. Detailed Implementation

[0034] According to this disclosure, a novel polymer may include an aromatic structural unit having one or more hydroxyl groups, as represented by the following chemical formula 1.

[0035] [Chemical Formula 1]

[0036]

[0037] In Formula 1, the Ar group is a C6-C30 aryl or a C6-C30 heteroaryl, wherein the C6-C30 aryl or C6-C30 heteroaryl may be substituted with a hydroxyl group, a halogen group, an alkyl group, or an alkoxy group.

[0038] Furthermore, the Ar group in Formula 1 is an aromatic aryl or heteroaryl compound capable of forming a condensation polymer with a phenyl or naphthyl aldehyde compound having one or more hydroxyl groups.

[0039] In this formula, 'x' is in the range of 0 to 2, and 'y' is 0 or 1.

[0040] Additionally, 'n' can be in the range of 5 to 100.

[0041] The Ar group may preferably have at least one of the structures represented by the following chemical formula 2.

[0042] [Chemical Formula 2]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048] Meanwhile, the weight-average molecular weight (Mw) of the aromatic polymer is in the range of 1,000 to 30,000, and preferably 1,500 to 15,000.

[0049] Polymers comprising aromatic structural units of chemical formula 1 may have, for example, the forms of chemical formulas 2-1 to 2-26 shown below.

[0050] [Chemical Formula 2-1]

[0051]

[0052] [Chemical Formula 2-2]

[0053]

[0054] [Chemical Formula 2-3]

[0055]

[0056] [Chemical Formula 2-4]

[0057]

[0058] [Chemical Formula 2-5]

[0059]

[0060] [Chemical Formula 2-6]

[0061]

[0062] [Chemical Formula 2-7]

[0063]

[0064] [Chemical Formula 2-8]

[0065]

[0066] [Chemical Formula 2-9]

[0067]

[0068] [Chemical Formula 2-10]

[0069]

[0070] [Chemical Formula 2-11]

[0071]

[0072] [Chemical Formula 2-12]

[0073]

[0074] [Chemical Formula 2-13]

[0075]

[0076] [Chemical Formula 2-14]

[0077]

[0078] [Chemical Formula 2-15]

[0079]

[0080] [Chemical Formula 2-16]

[0081]

[0082] [Chemical Formula 2-17]

[0083]

[0084] [Chemical Formula 2-18]

[0085]

[0086] [Chemical Formula 2-19]

[0087]

[0088] [Chemical Formula 2-20]

[0089]

[0090] [Chemical Formula 2-21]

[0091]

[0092] [Chemical Formula 2-22]

[0093]

[0094] [Chemical Formula 2-23]

[0095]

[0096] [Chemical Formula 2-24]

[0097]

[0098] [Chemical Formula 2-25]

[0099]

[0100] [Chemical Formula 2-26]

[0101]

[0102] In addition, the hard mask composition disclosed herein is an anti-reflective hard mask composition comprising the following components:

[0103] (a) A polymer or blend thereof having an aromatic structural unit having one or more hydroxyl groups as represented by Formula 1; and

[0104] (b) Organic solvents.

[0105] [Chemical Formula 1]

[0106]

[0107] In Formula 1, the Ar group is a C6-C30 aryl or a C6-C30 heteroaryl, wherein the C6-C30 aryl or C6-C30 heteroaryl may be substituted with a hydroxyl group, a halogen group, an alkyl group, or an alkoxy group.

[0108] Furthermore, the Ar group in Formula 1 is an aromatic aryl or heteroaryl compound capable of forming a condensation polymer with a phenyl or naphthyl aldehyde compound having one or more hydroxyl groups.

[0109] In this formula, 'x' is in the range of 0 to 2, and 'y' is 0 or 1.

[0110] Additionally, 'n' can be in the range of 5 to 100.

[0111] Meanwhile, the weight-average molecular weight (Mw) of the aromatic polymer is in the range of 1,000 to 30,000, and preferably 1,500 to 15,000.

[0112] The Ar group may preferably have at least one of the structures represented by the following chemical formula 2.

[0113] [Chemical Formula 2]

[0114]

[0115]

[0116]

[0117]

[0118]

[0119] Furthermore, the polymers in (a) that include aromatic structural units having one or more hydroxyl groups as represented by chemical formula 1 can take the form of, for example, chemical formulas 2-1 to 2-26 as described above.

[0120] Furthermore, the polymer in (a) comprising the aromatic structural unit represented by the above chemical formula 1 can be an aromatic polymer in the form of a terpolymer, which, in addition to the structural unit of chemical formula 1, is also synthesized by using other types of aldehyde compounds such as benzaldehyde, naphthaldehyde or fluorene.

[0121] In addition to the polymers in (a), aromatic C6-C20 phenolic varnish polymers or phenolic varnish resins with hydroxyl groups may be blended to improve the solubility, coatability or curability of the hard mask composition.

[0122] In order to prepare the hard mask composition, based on 100% by weight of the total composition, the amount of the polymer or blend thereof comprising an aromatic structural unit having one or more hydroxyl groups represented by Formula 1 in (a) is preferably from 1% by weight to 30% by weight.

[0123] If the amount of 'polymer or blend thereof' in (a) is less than 1% by weight or more than 30% by weight, it is difficult to achieve a precise target coating thickness because the resulting thickness may be below or above the required range.

[0124] (b) The amount of organic solvent used is the amount excluding other components from 100% by weight of the total composition. There are no particular limitations on the organic solvent, as long as it has sufficient solubility for the polymer containing an aromatic ring, and examples include propylene glycol monomethyl ether acetate (PGMEA), cyclohexanone, ethyl lactate, and γ-butyrolactone (GBL).

[0125] In addition, the antireflective hard mask composition disclosed herein may also include (c) a crosslinking agent component and (d) an acid catalyst.

[0126] The crosslinking agent component in (c) of the hard mask composition disclosed herein is preferably capable of crosslinking the repeating units of the polymer by heating under the action of the generated acid. The acid catalyst in (d) is preferably a thermally activated acid catalyst.

[0127] There are no particular restrictions on the crosslinking agent in (c), as long as it can react with the aromatic polymer in a manner that can be catalyzed by the generated acid.

[0128] Examples of crosslinking agents include melamine-based compounds, substituted urea-based compounds, or polymeric compounds thereof. Preferably, the crosslinking agent has at least two crosslinking substituents, and examples include compounds such as: methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxymethylated benzoguanamine, methoxymethylated urea, butoxymethylated urea, and methoxymethylated thiourea.

[0129] In addition, crosslinking agents with high heat resistance can be used, and preferably compounds containing crosslinking substituents with aromatic rings in the molecule can be used.

[0130] Examples of such compounds include those represented by the following structural formulas.

[0131]

[0132]

[0133] The acid catalyst used in (d) of the hard mask composition disclosed herein can be an organic acid, such as p-toluenesulfonic acid monohydrate. Furthermore, thermogenic acid (TAG) compounds can be used as catalysts to improve storage stability.

[0134] TAG is an acid-generating compound designed to release acid during heat treatment. For example, compounds such as pyridinium p-toluenesulfonate, 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl toluenesulfonate, and alkyl esters of organic sulfonic acids are preferred.

[0135] When the hard mask composition further comprises (c) a crosslinking agent component and (d) an acid catalyst, the hard mask composition may consist of: (a) 1 wt% to 30 wt% and preferably 5 wt% to 20 wt% of a polymer or blend thereof that has strong absorption in the UV region; (c) 0.1 wt% to 5 wt% and preferably 0.1 wt% to 3 wt% of a crosslinking agent component; (d) 0.001 wt% to 0.05 wt% and preferably 0.001 wt% to 0.03 wt% of an acid catalyst; and (b) the balance being an organic solvent, such that the total is 100 wt%. Preferably, the composition contains 75 wt% to 98 wt% of an organic solvent.

[0136] If the amount of polymer or blend in (a) is less than 1% by weight or more than 30% by weight, it is difficult to achieve a precise target coating thickness because the thickness may be below or above the required range.

[0137] Furthermore, if the amount of the crosslinking agent component in (c) is less than 0.1% by weight, it may not exhibit crosslinking properties, while if it exceeds 5% by weight, it may alter the optical properties of the coating film due to excessive addition.

[0138] Furthermore, if the amount of acid catalyst in (d) is less than 0.001% by weight, it may not be able to adequately exhibit crosslinking properties, while if it exceeds 0.05% by weight, the increase in acidity caused by excessive addition may negatively affect storage stability.

[0139] The present disclosure will be described in more detail below with reference to various embodiments. However, the following embodiments are provided for illustrative purposes only and are not intended to limit the scope of the disclosure.

[0140] <Polymer Synthesis>

[0141] Implementation Plan 1: Polymer Synthesis

[0142] [Chemical Formula 2-1]

[0143]

[0144] In a 250 mL round-bottom flask, pyrene (70 mmol) and 4-hydroxybenzaldehyde (90 mmol) were completely dissolved in γ-butyrolactone (GBL) (2.5 times the total weight of the monomers). Subsequently, 10 mol% p-toluenesulfonic acid (PTSA) was added, and polymerization was carried out at 130 °C for 20 hours.

[0145] After polymerization, the reaction product was precipitated in an excess methanol / water (7:3) cosolvent, and then neutralized with triethylamine. The resulting precipitate was filtered and washed twice with an excess methanol solution. The precipitate was then collected and dried in a vacuum oven at 70°C for 24 hours to obtain the polymer represented by chemical formula 2-1.

[0146] The polymer of chemical formula 2-1 has a weight-average molecular weight (Mw) of 2,400 and a polydispersity index (Mw / Mn) of 2.27.

[0147] Implementation Scheme 2: Polymer Synthesis

[0148] [Chemical Formula 2-2]

[0149]

[0150] Except for the use of pyrene (70 mmol) and 2,4-dihydroxybenzaldehyde (90 mmol), the polymer represented by chemical formula 2-2 was synthesized in the same manner as in embodiment 1.

[0151] The polymer of chemical formula 2-2 has a weight-average molecular weight (Mw) of 2,300 and a polydispersity index (Mw / Mn) of 2.54.

[0152] Implementation Plan 3: Polymer Synthesis

[0153] [Chemical Formula 2-3]

[0154]

[0155] Except for the use of pyrene (70 mmol) and 2-hydroxy-1-naphthaldehyde (90 mmol), the polymers represented by chemical formulas 2-3 were synthesized in the same manner as in embodiment 1.

[0156] The polymers of chemical formulas 2-3 have a weight-average molecular weight (Mw) of 3,100 and a polydispersity index (Mw / Mn) of 2.59.

[0157] Implementation Scheme 4: Polymer Synthesis

[0158] [Chemical Formula 2-6]

[0159]

[0160] The polymers represented by chemical formulas 2-6 were synthesized in the same manner as in embodiment 1, except that indole (100 mmol) and 4-hydroxybenzaldehyde (110 mmol) were used.

[0161] The polymers of chemical formulas 2-6 have a weight-average molecular weight (Mw) of 5,900 and a polydispersity index (Mw / Mn) of 2.17.

[0162] Implementation Scheme 5: Polymer Synthesis

[0163] [Chemical Formula 2-8]

[0164]

[0165] The polymers represented by chemical formulas 2-8 were synthesized in the same manner as in embodiment 1, except that indole (100 mmol) and 2-hydroxy-1-naphthaldehyde (110 mmol) were used.

[0166] The polymers of chemical formula 2-8 have a weight-average molecular weight (Mw) of 4,700 and a polydispersity index (Mw / Mn) of 2.38.

[0167] Implementation Scheme 6: Polymer Synthesis

[0168] [Chemical Formula 2-9]

[0169]

[0170] The polymers represented by chemical formulas 2-9 were synthesized in the same manner as in embodiment 1, except that carbazole (100 mmol) and 4-hydroxybenzaldehyde (110 mmol) were used.

[0171] The polymers of chemical formulas 2-9 have a weight-average molecular weight (Mw) of 3,900 and a polydispersity index (Mw / Mn) of 2.57.

[0172] Implementation Plan 7: Polymer Synthesis

[0173] [Chemical Formula 2-10]

[0174]

[0175] The polymers represented by chemical formulas 2-10 were synthesized in the same manner as in embodiment 1, except that carbazole (100 mmol) and 2,4-dihydroxybenzaldehyde (110 mmol) were used.

[0176] The polymer of chemical formula 2-10 has a weight-average molecular weight (Mw) of 3,300 and a polydispersity index (Mw / Mn) of 2.36.

[0177] Implementation Scheme 8: Polymer Synthesis

[0178] [Chemical Formula 2-11]

[0179]

[0180] Except for the use of carbazole (100 mmol) and 2-hydroxy-1-naphthaldehyde (110 mmol), the polymer represented by chemical formula 2-11 was synthesized in the same manner as in embodiment 1.

[0181] The polymer of chemical formula 2-11 has a weight-average molecular weight (Mw) of 3,700 and a polydispersity index (Mw / Mn) of 2.28.

[0182] Implementation Scheme 9: Polymer Synthesis

[0183] [Chemical Formula 2-13]

[0184]

[0185] Except for the use of phenylcarbazole (100 mmol) and 4-hydroxybenzaldehyde (110 mmol), the polymer represented by chemical formula 2-13 was synthesized in the same manner as in embodiment 1.

[0186] The polymer of chemical formula 2-13 has a weight-average molecular weight (Mw) of 4,300 and a polydispersity index (Mw / Mn) of 2.18.

[0187] Implementation Scheme 10: Polymer Synthesis

[0188] [Chemical Formula 2-15]

[0189]

[0190] The polymers represented by chemical formulas 2-15 were synthesized in the same manner as in embodiment 1, except that phenylcarbazole (100 mmol) and 2-hydroxy-1-naphthaldehyde (110 mmol) were used.

[0191] The polymer of chemical formula 2-15 has a weight-average molecular weight (Mw) of 3,800 and a polydispersity index (Mw / Mn) of 2.18.

[0192] Implementation Scheme 11: Polymer Synthesis

[0193] [Chemical Formula 2-16]

[0194]

[0195] The polymers represented by chemical formulas 2-16 were synthesized in the same manner as in embodiment 1, except that naphthylcarbazole (100 mmol) and 4-hydroxybenzaldehyde (110 mmol) were used.

[0196] The polymer of chemical formula 2-16 has a weight-average molecular weight (Mw) of 3,900 and a polydispersity index (Mw / Mn) of 2.28.

[0197] Implementation Scheme 12: Polymer Synthesis

[0198] [Chemical Formula 2-18]

[0199]

[0200] Except for the use of naphthylcarbazole (100 mmol) and 2-hydroxy-1-naphthaldehyde (110 mmol), the polymer represented by chemical formula 2-18 was synthesized in the same manner as in embodiment 1.

[0201] The polymer of chemical formula 2-18 has a weight-average molecular weight (Mw) of 3,300 and a polydispersity index (Mw / Mn) of 2.28.

[0202] Implementation Scheme 13: Polymer Synthesis

[0203] [Chemical Formula 2-20]

[0204]

[0205] The polymers represented by chemical formulas 2-20 were synthesized in the same manner as in Example 1, except that pyrenecarbazole (60 mmol) and 4-hydroxybenzaldehyde (70 mmol) were used.

[0206] The polymer of chemical formula 2-20 has a weight-average molecular weight (Mw) of 3,100 and a polydispersity index (Mw / Mn) of 2.38.

[0207] Implementation Scheme 14: Polymer Synthesis

[0208] [Chemical Formula 2-22]

[0209]

[0210] Except for the use of pyrene carbazole (60 mmol) and 2-hydroxy-1-naphthaldehyde (70 mmol), the polymer represented by chemical formula 2-22 was synthesized in the same manner as in embodiment 1.

[0211] The polymer of chemical formula 2-22 has a weight-average molecular weight (Mw) of 2,900 and a polydispersity index (Mw / Mn) of 2.38.

[0212] Implementation Scheme 15: Polymer Synthesis

[0213] [Chemical Formula 2-23]

[0214]

[0215] The polymers represented by chemical formulas 2-23 were synthesized in the same manner as in embodiment 1, except that phenyl-1-naphthylamine (100 mmol) and 4-hydroxybenzaldehyde (110 mmol) were used.

[0216] The polymer of chemical formula 2-23 has a weight-average molecular weight (Mw) of 3,600 and a polydispersity index (Mw / Mn) of 2.33.

[0217] Implementation Scheme 16: Polymer Synthesis

[0218] [Chemical Formula 2-24]

[0219]

[0220] The polymers represented by chemical formulas 2-24 were synthesized in the same manner as in embodiment 1, except that phenyl-1-naphthylamine (100 mmol) and 2-hydroxy-1-naphthaldehyde (110 mmol) were used.

[0221] The polymer of chemical formula 2-24 has a weight-average molecular weight (Mw) of 3,300 and a polydispersity index (Mw / Mn) of 2.38.

[0222] Implementation Scheme 17: Polymer Synthesis

[0223] [Chemical Formula 2-25]

[0224]

[0225] The polymers represented by chemical formulas 2-25 were synthesized in the same manner as in Embodiment 1, except that 2,2'-dinaphthylamine (80 mmol) and 4-hydroxybenzaldehyde (90 mmol) were used.

[0226] The polymer of chemical formula 2-25 has a weight-average molecular weight (Mw) of 3,800 and a polydispersity index (Mw / Mn) of 2.41.

[0227] Comparative example: Synthesis of phenolic polymers

[0228]

[0229] 9,9-bis(hydroxyphenyl)fluorene (100 mmol) and benzaldehyde (110 mmol) were dissolved in GBL, followed by the addition of 5 mol% p-toluenesulfonic acid.

[0230] After polymerization in the same manner as in Embodiment 1, the polymer was purified and dried in a vacuum oven to obtain a polymer with a weight-average molecular weight (Mw) of 3,300.

[0231] <Preparation of Hard Mask Composition>

[0232] One g of each polymer prepared in Embodiments 1, 3, 5, 8, 10, 12, 13 and 14 and the Comparative Example was added together with 300 ppm of surfactant (relative to polymer weight) to a solvent mixture of 6 g propylene glycol monomethyl ether acetate (PGMEA) and 4 g cyclohexanone, and completely dissolved. The solution was then filtered through a 0.2 μm membrane filter to prepare sample solutions of the hard mask compositions of Embodiments 1, 3, 5, 8, 10, 12, 13 and 14 and the Comparative Example, respectively.

[0233] The hard mask composition sample solutions of embodiments 1, 3, 5, 8, 10, 12, 13 and 14 and the comparative example were each spin-coated onto a silicon wafer and then baked at 400°C for 120 seconds to form a film with a thickness of 3,000 Å.

[0234] The refractive index (n) and extinction coefficient (k) of the formed film were measured using an ellipsomerometer (manufactured by JA Woollam), and the results are shown in Table 1 below.

[0235] As a result of the evaluation, it was confirmed that the film has a refractive index and absorbance suitable for use as an antireflective coating at wavelengths of ArF (193 nm) and KrF (248 nm).

[0236] Typically, the refractive index of materials used as semiconductor antireflective coatings ranges from about 1.4 to 1.8. Although the extinction coefficient is a critical factor and higher absorbance is generally preferred, a k value above 0.3 is generally sufficient for use as an antireflective coating. Therefore, it can be seen that the hard mask compositions according to embodiments of the present disclosure are suitable for use as antireflective coatings.

[0237] [Table 1]

[0238]

[0239] <Photolithographic Evaluation of Anti-reflective Hard Mask Compositions>

[0240] Using the polymers of embodiments 1, 4, 6, 8, 11 and 14 and the comparative example, sample solutions prepared in the same manner as the hard mask compositions described above were spin-coated onto silicon wafers deposited with aluminum. The coated silicon wafers were then baked at 240°C for 60 seconds to form a coating film with a thickness of 3,000 Å.

[0241] The KrF photoresist was coated onto the formed individual coating films, baked at 110°C for 60 seconds, and exposed using an exposure system from ASML (XT:1400, NA 0.93). Subsequently, the films were developed with an aqueous solution of 2.38 wt% tetramethylammonium hydroxide (TMAH) for 60 seconds. Afterwards, a 90 nm line-and-space pattern was observed using V-SEM, and the results are given in Table 2 below.

[0242] In addition, the exposure latitude (EL) margin based on the change in exposure dose and the depth of focus (DoF) margin based on the change in distance from the light source were examined and recorded in Table 2.

[0243] The pattern evaluation results confirmed favorable profile and margin. The hard mask composition was found to meet the EL and DoF margin requirements for lithographic pattern evaluation.

[0244] [Table 2]

[0245]

[0246] Evaluation of the Etching Properties of Anti-Reflective Hard Mask Compositions

[0247] The hard mask compositions were prepared by completely dissolving 1 g of each polymer from Embodiments 1, 3, 5, 8, 10, 12, 13, and 14, as well as the comparative examples, with 300 ppm of surfactant (relative to polymer weight) in a solvent mixture of 6 g propylene glycol monomethyl ether acetate (PGMEA) and 4 g cyclohexanone. The compositions were then heat-treated at 400 °C for 120 seconds to form thin films. Subsequently, dry etching was performed for 60 seconds using a N2 / O2 mixed gas (at 50 mT / 300 W / 10 O2 / 50 N2) and a CFx gas (at 100 mT / 600 W / 42 CF4 / 600 Ar / 15 O2), respectively. The thickness of each film was measured before and after etching.

[0248] The etching rate ( / s) was calculated by dividing the change in film thickness by the etching time. The results are given in Table 3 below.

[0249] [Table 3]

[0250]

[0251] As shown in Table 3 above, the film formed according to the embodiment exhibits significantly better etch resistance compared to the film formed according to the comparative example.

[0252] Based on these bulk etch characteristics, the hard mask composition prepared according to the embodiments is expected to serve as a very effective anti-reflective hard mask for photolithographic pattern formation.

[0253] While preferred embodiments of this disclosure have been described in detail above, the scope of this disclosure is not limited thereto. Various changes and modifications made by those skilled in the art using the basic concept of this disclosure, as defined in the appended claims, are also within the scope of this disclosure.

Claims

1. A polymer comprising only aromatic structural units having one or more hydroxyl groups, as represented by the following chemical formula 1, wherein the Ar group in chemical formula 1 is a group composed of only a single type of structural unit: [Chemical Formula 1] The Ar group is a C6-C30 aryl or a C6-C30 heteroaryl, wherein the C6-C30 aryl or C6-C30 heteroaryl may optionally be substituted by the following groups: hydroxyl, halogen group, alkyl, alkoxy or amine group having a substituent; The Ar group in Formula 1 is an aromatic aryl or heteroaryl compound capable of forming a condensation polymer with a phenyl or naphthyl aldehyde compound having one or more hydroxyl groups; 'x' is in the range of 0 to 2, and 'y' is 0 or 1; 'n' is between 5 and 100; and The weight-average molecular weight (Mw) of the polymer is in the range of 1,000 to 30,000.

2. The polymer according to claim 1, wherein the Ar group is one of the structures represented by the following chemical formula 2: [Chemical Formula 2] 。 3. The polymer according to claim 1, wherein the polymer consisting solely of the aromatic structural units is one of the following chemical formulas 2-1 to 2-26: [Chemical Formula 2-1] [Chemical Formula 2-2] [Chemical Formula 2-3] [Chemical Formula 2-4] [Chemical Formula 2-5] [Chemical Formula 2-6] [Chemical Formula 2-7] [Chemical Formula 2-8] [Chemical Formula 2-9] [Chemical Formula 2-10] [Chemical Formula 2-11] [Chemical Formula 2-12] [Chemical Formula 2-13] [Chemical Formula 2-14] [Chemical Formula 2-15] [Chemical Formula 2-16] [Chemical Formula 2-17] [Chemical Formula 2-18] [Chemical Formula 2-19] [Chemical Formula 2-20] [Chemical Formula 2-21] [Chemical Formula 2-22] [Chemical Formula 2-23] [Chemical Formula 2-24] [Chemical Formula 2-25] [Chemical Formula 2-26] 。 4. An anti-reflective hard mask composition, said anti-reflective hard mask composition comprising: (a) the polymer or blend thereof according to any one of claims 1 to 3; and (b) Organic solvents.

5. The anti-reflective hard mask composition according to claim 4, wherein the anti-reflective hard mask composition further comprises: Crosslinking agent components and acid catalysts.

6. The anti-reflective hard mask composition according to claim 5, wherein the composition comprises the following: (a) 1% to 30% by weight of the polymer or blend thereof comprising aromatic polymeric structural units; (b) 0.1% to 5% by weight of the crosslinking agent component; (c) 0.001% to 0.05% by weight of the acid catalyst; and (d) The remainder of the organic solvent, so that the total is 100 by weight.

7. The antireflective hard mask composition according to claim 5, wherein the crosslinking agent component is selected from any one of the following: methoxymethylated glycourea, butoxymethylated glycourea, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxymethylated benzoguanamine, methoxymethylated urea, butoxymethylated urea and methoxymethylated thiourea.

8. The antireflective hard mask composition according to claim 5, wherein the acid catalyst is selected from any one of the following groups: p-toluenesulfonic acid monohydrate, p-toluenesulfonic acid pyridinium, 2,4,4,6-tetrabromocyclohexadienone, benzoin toluenesulfonate, 2-nitrobenzyl toluenesulfonate, and alkyl esters of organic sulfonic acids.

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