KR20200112363A - A composition of anti-reflective hardmask - Google Patents

Abstract

The present invention relates to an anti-reflective hardmask composition comprising: (a) an arylcarbazole-fluorene-based copolymer represented by chemical formula (1) or a copolymer blend comprising the same; and (b) an organic solvent and, more specifically, to a hardmask composition with excellent etching resistance.

Description

Anti-reflection hard mask composition {A COMPOSITION OF ANTI-REFLECTIVE HARDMASK}

The present invention relates to a hardmask composition having antireflection properties useful in a lithographic process, and a polymer containing an arylcarbazole-fluorene-based aromatic ring having strong absorption in an ultraviolet wavelength region, and It relates to a hard mask composition comprising the same.

In recent years, as the semiconductor industry increasingly requires microscopic processes, an effective lithographic process is essential to realize such ultra-fine technology. In particular, there is an increasing demand for a new material for a hardmask process that is very essential in the etching process.

In general, the hardmask film quality serves as an interlayer that transfers a fine pattern of a photoresist to a lower substrate layer through a selective etching process. Therefore, the hard mask layer is required to have properties such as chemical resistance, heat resistance, and etching resistance to withstand multiple etching processes. The existing hard mask film quality was made of an amorphous carbon layer (ACL) film made by chemical vapor deposition (CVD). The disadvantages of this are high cost equipment investment and particle and film quality opaque. There were many very inconvenient points to use due to photo alignment problems, etc.

Recently, instead of the chemical vapor deposition method, a spin-on hardmask method formed by a spin-on coating method has been introduced. In the spin-on coating method, a hardmask composition is formed using an organic polymer material having solubility in a solvent, and the most important characteristic is that an organic polymer coating film having both etching resistance must be formed.

However, the characteristics of solubility and etching resistance, which are two properties required for the organic hardmask layer, are in conflict with each other, so a hardmask composition capable of satisfying all of them was required. While satisfying the characteristics of these organic hardmask materials, materials introduced into the semiconductor lithographic process have been recently introduced (Publication Patent 10-2009-0120827, Publication 10-2008-0107210, Patent WO 2013100365 A1), which is These were hard mask materials using a copolymer having an appropriate high molecular weight synthesized by the conventional phenol resin manufacturing method using ren (hydroxypyrene).

In addition, a composition (Patent Publication No. 10-2012-0038447) was introduced that produced a novolac resin using carbazole and used it as a resist underlayer film.

However, as the recent semiconductor lithographic process goes through a further refinement process, in the case of such an organic hardmask material, it is difficult to sufficiently perform the role of a mask due to the lack of etching selectivity in the etching process compared to the conventional inorganic hardmask material. Came. Therefore, there is an urgent need to introduce an organic hardmask material more optimized for the etching process.

An object of the present invention is to provide a hardmask polymer having excellent polymer solubility, high etching selectivity, and sufficient resistance to multi-etching, and a composition containing the same.

An object of the present invention is to provide a novel hardmask polymer that can be used to perform a lithographic technique, and a composition comprising the same, since reflectivity between a resist and a back layer can be minimized.

The hardmask composition according to the embodiments of the present invention includes (a) an arylcarbazole-fluorene-type copolymer represented by the following Formula 1 or a copolymer blend comprising the same; And

(b) an organic solvent;

Anti-reflection hardmask composition comprising a.

[Formula 1]

The hardmask composition based on the arylcarbazole-florenic polymer according to the embodiments of the present invention has a very high polymerization rate compared to the conventional phenolic polymer.

The hardmask composition based on the arylcarbazole-florenic polymer according to the embodiments of the present invention has a very high packing density, so that when a thin film is formed, the film density increases and the etching resistance is very excellent. Accordingly, since the etching selectivity is high compared to the existing organic hard mask, the resistance to multiple etching is sufficient, and a lithographic structure having excellent pattern evaluation results can be provided.

The hard mask composition based on the arylcarbazole-florenic polymer according to the embodiments of the present invention is a useful range of refractive index and absorption as an antireflection film in the Deep UV region such as ArF (193 nm) and KrF (248 nm) during film formation. By having a, it is possible to minimize the reflectivity between the resist and the back layer.

According to the present invention, there is provided an anti-reflective hardmask composition comprising an arylcarbazole-florene-based copolymer represented by the following Formula 1 or a copolymer blend comprising the same, and (b) an organic solvent.

[Formula 1]

In the above formula, the R group is hydrogen or a C1 to C10 alkyl, alkenyl, C6 to C20 aryl group, and preferably has a C6 to C20 aryl structure.

In addition, X is composed of a polymer of florenone and C6 to C40 aromatic compounds having at least one hydroxy group (OH) in order to increase the solubility and curability of the arylcarbazole-florenic structure, and a preferred aromatic structure Consists of a compound of the form below.

Here, m/(m+n)= has a range of 0.05 to 0.95, and the weight average molecular weight (Mw) of the entire copolymer is between 1,000 and 30,000, and preferably may have a range between 1,000 and 5,000.

Meanwhile, in order to make a hardmask composition, the (a) arylcarbazole-florene-based copolymer is preferably used in an amount of 1 to 30% by weight based on 100 parts by weight of the (b) organic solvent used. When the arylcarbazole-florene-based copolymer is used in an amount of less than 1 part by weight or more than 30 parts by weight, it becomes less than or exceeds the desired coating thickness, making it difficult to match the exact coating thickness.

And the organic solvent is not particularly limited as long as it has sufficient solubility in the above aromatic ring-containing polymer, for example, propylene glycol monomethyl ether acetate (PGMEA), cyclohexanone, ethyl lactate, etc. have.

In addition, the antireflection hardmask composition of the present invention may further include (c) a crosslinking agent component and (d) an acid catalyst.

The (c) crosslinking agent component used in the hardmask composition of the present invention is preferably capable of crosslinking the repeating units of the polymer by heating in a reaction catalyzed by the generated acid, and the (d) acid catalyst is It is preferably an activated acid catalyst.

The (c) crosslinking agent component used in the hardmask composition of the present invention is not particularly limited as long as it is a crosslinking agent capable of reacting with a hydroxy group of an aromatic ring-containing polymer in a manner that can be catalytically functionalized by the produced acid. Specifically, for example, 　 etherified amino resin, such as methylated or butylated melamine resin (specific example, N-methoxymethyl-melamine resin or N-butoxymethyl-melamine resin) and methylated Or butylated urea resin (for example, Cymel U-65 Resin or UFR 80 Resin), a glycoluril compound (for example, Powderlink 1174), or a bisepoxy compound (for example, 2 ,6-bis(hydroxymethyl)-p-cresol compound), etc. are mentioned.

As the (d) acid catalyst used in the hardmask composition of the present invention, an organic acid such as p-toluenesulfonic acid monohydrate may be used, and TAG (Thermal Acid Generator) having storage stability A system compound can also be used as a catalyst. TAG is an acid generator compound designed to release an acid during heat treatment. For example, pyridinium P-toluene sulfonate, 2,4,4,6-tetrabromocyclohexadienone, It is preferable to use benzoin tosylate, 2-nitrobenzyl tosylate, and alkyl esters of organic sulfonic acids.

When the final hardmask composition further comprises (c) a crosslinking agent component and (d) an acid catalyst, the hardmask composition of the present invention comprises (a) an arylcarbazole-florene type having strong absorption properties in the ultraviolet region. 1 to 30% by weight, more preferably 3 to 15% by weight, and (c) 0.1 to 5% by weight of the crosslinking agent component, more preferably 0.1 to 3% by weight is used, and (d) 0.001 to 0.05% by weight of an acid catalyst, more preferably 0.001 to 0.03% by weight, and (b) may be made of 100% by weight using an organic solvent as the remaining component, preferably It is preferable to contain 75 to 98% by weight of an organic solvent.

Here, when the aromatic ring-containing polymer is less than 1% by weight or more than 30% by weight, it becomes less than or exceeds the desired coating thickness, making it difficult to match the exact coating thickness.

In addition, when the crosslinking agent component is less than 0.1% by weight, crosslinking properties may not appear, and when it exceeds 5% by weight, the optical properties of the coating film may be changed by excessive injection.

In addition, when the acid catalyst is less than 0.001% by weight, crosslinking characteristics may not be exhibited well, and when it exceeds 0.05% by weight, storage stability may be affected due to an increase in acidity due to excessive injection.

Hereinafter, the present invention will be described in more detail through examples, but the following examples are for the purpose of explanation only and are not intended to limit the scope of the present invention.

Manufacturing Example 1

In a 250 mL round flask, add 24.5 g (100 mmol) of phenylcarbazole, 22 g (120 mmol) of 9-fluorenone, and 9.5 g (100 mmol) of phenol 130 g of 1,2-dichloroethane. After cleanly dissolving in, 10 g of trifluoromethanesulfonic acid is added thereto.

After polymerization for about 12 hours while maintaining the reaction temperature at about 80℃,

The reaction product was diluted in an appropriate amount of dichloromethane solvent and then dropped into an excess of water, followed by extraction and neutralization. Subsequently, the organic layer in which layer separation has occurred is dissolved in an appropriate amount of THF solvent after blowing off the solvent, and then dropped into an excess of methanol to catch precipitation. After drying the precipitate in a vacuum oven at 50°C, a polymer having a weight average molecular weight (Mw) of 2,200 was obtained.

Manufacturing Example 2

Phenylcarbazole 24.5g (100mmol), flurenone 22g (120mmol), and 2-naphthol 14.5g (100mmol) was synthesized in the same manner as in Preparation Example 1.

After polymer purification, a weight average molecular weight (Mw) of 2,100 polymer was obtained.

Manufacturing Example 3

Naphthylcarbazole 29.5g (100mmol), flurenone 22g (120mmol), and 2-naphthol 14.5g (100mmol) were synthesized in the same manner as in Preparation Example 1.

After polymer purification, a weight average molecular weight (Mw) of 1,900 polymer was obtained.

Manufacturing Example 4

Phenylcarbazole 24.5g (100mmol), fluorenone 22g (120mmol), and pyrenol (pyrenol) 22g (100mmol) was synthesized in the same manner as in Preparation Example 1.

After polymer purification, a polymer having a weight average molecular weight (Mw) of 2,000 was obtained.

Manufacturing Example 5

Naphthylcarbazole 29.5g (100mmol), flurenone 22g (120mmol), and pyrenol 22g (100mmol) were synthesized in the same manner as in Preparation Example 1.

After polymer purification, a weight average molecular weight (Mw) of 2,200 polymer was obtained.

Manufacturing Example 6

Phenanthrylcarbazole 17.2g (50mmol), flurenone 11g (60mmol), and 2-naphthol 7.3g (50mmol) were synthesized in the same manner as in Preparation Example 1.

After polymer purification, a weight average molecular weight (Mw) of 2,100 polymer was obtained.

Manufacturing Example 7

Naphthylcarbazole 29.5g (100mmol), flurenone 22g (120mmol), and 9,9-bishydroxyphenylfluorene 35g (100mmol) were synthesized in the same manner as in Preparation Example 1.

After polymer purification, a weight average molecular weight (Mw) of 2,500 polymer was obtained.

Manufacturing Example 8

Phenylcarbazole 12.3g (50mmol), fluorenone 11g (60mmol), and 9,9-bishydroxynaphthylfluorene 23g (50mmol) were synthesized in the same manner as in Preparation Example 1.

After polymer purification, a weight average molecular weight (Mw) of 2,300 polymer was obtained.

Manufacturing Example 9

Carbazole 17g (100mmol), flurenone 22g (120mmol), and 2-naphthol 14.5g (100mmol) were synthesized in the same manner as in Preparation Example 1.

After polymer purification, a weight average molecular weight (Mw) of 2,200 polymer was obtained.

Manufacturing Example 10

19.5 g (100 mmol) of ethylcarbazole, 22 g (120 mmol) of fluorenone, and 14.5 g (100 mmol) of 2-naphthol were synthesized in the same manner as in Preparation Example 1.

After polymer purification, a weight average molecular weight (Mw) of 2,300 polymer was obtained.

Comparative Production Example) Synthesis of phenolic polymer

After dissolving 35 g (100 mmol) of 9,9-bishydroxyphenylfluorene and 12.7 g (120 mmol) of benzaldehyde in 115 g of PGMEA, 1 g of concentrated sulfuric acid is added thereto.

After polymerization in the same manner as in Preparation Example 1, the polymer was purified and dried in a vacuum oven to obtain a polymer having a weight average molecular weight of 3,300.

[Production Examples 1 to 10 and Comparative Production Examples]

Preparation of hard mask composition

The polymers prepared in Preparation Examples 1 to 10 and Comparative Preparation Examples were weighed by 0.9 g each, and 0.1 g of glycoluril compound crosslinking agent (Powderlink 1174) and pyridinium P-toluene sulfonate 　 1 mg were added to propylene glycol monomethyl After dissolving in 9 g of ether acetate (PGMEA), it was filtered to prepare sample solutions of Preparation Examples 1 to 10 and Comparative Preparation Examples, respectively.

Sample solutions prepared according to Preparation Examples 1 to 10 and Comparative Preparation Examples were spin-coated on a silicon wafer, and baked at 240°C for 60 seconds to form a film having a thickness of 3000 Å.

At this time, the refractive index n and the extinction coefficient k of the formed films were obtained, respectively. The device used was Ellipsometer (J. A. Woollam), and the measurement results are shown in Table 1.

As a result of the evaluation, it was confirmed that there is a refractive index and absorbance that can be used as an antireflection film at ArF (193 nm) and KrF (248 nm) wavelengths. In general, the refractive index range of the material used as the semiconductor antireflection film is about 1.4 to 1.8, and the important thing is the extinction coefficient, which is better as the absorbance is higher, but if the k value is more than 0.3, there is no problem in using it as an antireflection film. It can be seen that the hardmask composition according to the examples can be used as an antireflection film.

Sample type Optical characteristics (193nm) Optical characteristics (248nm) Refractive index (n) Extinction coefficient (k) Refractive index (n) Extinction coefficient (k) Manufacturing Example 1 1.50 0.69 1.70 0.52 Manufacturing Example 2 1.51 0.71 1.71 0.52 Manufacturing Example 3 1.50 0.71 1.71 0.54 Manufacturing Example 4 1.52 0.69 1.70 0.52 Manufacturing Example 5 1.52 0.71 1.72 0.54 Manufacturing Example 6 1.53 0.70 1.73 0.54 Manufacturing Example 7 1.53 0.69 1.72 0.53 Manufacturing Example 8 1.54 0.71 1.72 0.53 Manufacturing Example 9 1.51 0.67 1.71 0.51 Manufacturing Example 10 1.51 0.68 1.72 0.50 Comparative Production Example 1.48 0.68 1.95 0.35

Lithographic evaluation of anti-reflective hardmask composition

Sample solutions prepared in Preparation Examples 2, 3, 5, 7 and Comparative Preparation Examples were spin-coated on a silicon wafer coated with aluminum, respectively, and baked at 240°C for 60 seconds to form a coating film having a thickness of 3000 Å.

After coating a photoresist for KrF on each of the formed coating films, bake at 110°C for 60 seconds, perform exposure using ASML (XT:1400, NA 0.93) exposure equipment, and then use TMAH (tetramethyl ammonium hydroxide) 2.38wt% aqueous solution. Each was developed for 60 seconds. Then, as a result of examining each of the 90 nm line and space patterns using V-SEM, the results shown in Table 2 were obtained. The exposure latitude (EL) margin according to the change in the exposure amount and the depth of focus (DoF) margin according to the distance from the light source were considered and recorded in Table 2. As a result of pattern evaluation, good results were confirmed in terms of profile and margin, and it was found that the EL margin and DoF margin required in the litho pattern evaluation were satisfied.

Sample type Pattern characteristics EL margin
(△mJ/energy mJ) DoF margin
(㎛) Pattern shape Manufacturing Example 2 0.3 0.3 cubic Manufacturing Example 3 0.3 0.3 cubic Manufacturing Example 5 0.4 0.3 cubic Manufacturing Example 7 0.4 0.4 cubic Comparative Production Example 0.2 0.2 undercut

Evaluation of etching properties for antireflective hardmask composition

In Preparation Examples 2, 3, 5, and Comparative Preparation Examples, each patterned specimen was dry-etched with a CHF ₃ /CF ₄ mixed gas using PR as a mask, followed by dry etching of the lower SiON antireflection film (BARC), followed by O ₂ /N ₂ Dry etching of this hard mask was performed again using the SiON antireflection film as a mask with the mixed gas. Afterwards, dry etching the silicon nitride (SiN) film quality by using the hard mask as a mask with CHF ₃ /CF ₄ mixed gas, and then O ₂ ashing and wet stripping process for the remaining hard mask and organic matter. Proceeded.

Immediately after hardmask etching and silicon nitride etching, the cross-sections of each specimen were examined with V-SEM, and the results are listed in Table 3. As a result of the etch evaluation, the pattern shape after hard mask etching and silicon nitride etching in each case did not show any bowing phenomenon, and both had good resistance due to the etching process, so that the etching process of the silicon nitride film was performed well. Confirmed.

Sample Pattern shape (after hard mask etching) Pattern shape (after SiN etching) Manufacturing Example 2 Vertical shape Vertical shape Manufacturing Example 3 Vertical shape Vertical shape Manufacturing Example 5 Vertical shape Vertical shape Comparative Production Example A little boeing Boeing

Claims (7)

(a) an arylcarbazole-fluorene-based copolymer represented by the following formula (1) or a copolymer mixture (blend) comprising the same; And
(b) an organic solvent;
Anti-reflection hardmask composition comprising a.
[Formula 1]

In the above formula, the R group is hydrogen or a C1 to C10 alkyl, alkenyl, C6 to C20 aryl group, and preferably has a C6 to C20 aryl structure.
In addition, X is composed of a polymer of florenone and C6 to C40 aromatic compounds having at least one hydroxy group (OH).

Here, m/(m+n)= has a range of 0.05 to 0.95, and the weight average molecular weight (Mw) of the entire copolymer is between 1,000 and 30,000, and preferably may have a range between 1,000 and 5,000. The method of claim 1,
The anti-reflection hardmask composition wherein the aromatic compound of X is any one selected from the following substituents, respectively.

The method of claim 1,
The hardmask composition wherein R is a vinyl (vinyl), phenyl (phenyl), naphthyl (naphtyl) group. The method of claim 1,
The hardmask composition is an antireflection hardmask composition further comprising a crosslinker and an acid catalyst component. The method of claim 4,
The hard mask composition,
(a) 1 to 30% by weight of the arylcarbazole-florene-based copolymer or a copolymer blend comprising the same;
(b) 0.1-5% by weight of a crosslinking agent component;
(c) 0.001 to 0.05% by weight of an acid catalyst; And
(d) An anti-reflective hard mask composition comprising 100% by weight of an organic solvent as the remaining component. The method of claim 5,
The crosslinking agent is any one selected from the group consisting of melamine resin, amino resin, glycoluril compound, and bisepoxy compound. The method of claim 5,
The acid catalyst is p-toluenesulfonic acid monohydrate, pyridinium p-toluene sulfonate, 2,4,4,6-tetrabromocyclohexadienone, benzo An antireflective hardmask composition selected from the group consisting of phosphorus tosylate, 2-nitrobenzyl tosylate, and alkyl esters of organic sulfonic acids.