KR20160086630A - New aromatic ring copolymers and hardmask compositions with anti-reflective property - Google Patents

Abstract

The present invention relates to a novel type hard mask polymer which is useful for a semiconductor lithographic process and has anti-reflective characteristics, and to a composition containing the same. The spirobifluorene-based polymer and the composition according to the present invention provide very excellent optical characteristics, mechanical characteristics, and hard mask etching selection ratio characteristic, and provide a coating film having excellent solubility characteristics and using a spin-on coating method.

Description

TECHNICAL FIELD The present invention relates to a novel aromatic ring copolymer and an antireflective hard mask composition containing the same,

The present invention relates to a hard mask polymer having antireflection film properties useful in lithographic processes, and is characterized by comprising a polymer containing an aromatic ring of spirobifluorene having strong absorption in the ultraviolet wavelength region and the polymer ≪ / RTI >

In recent years, the semiconductor industry is becoming increasingly refined, and an effective lithographic process is essential to realize such ultra-fine technology. In particular, there is a growing demand for new materials for the hard mask process, which is essential for the etching process.

Generally, the hard mask film acts as an interlayer to transfer the fine pattern of the photoresist to the lower substrate layer through the selective etching process. Therefore, the hard mask layer is required to have properties such as chemical resistance, heat resistance and etching resistance so as to withstand the multiple etching process. Conventional hard mask membranes used amorphous carbon layer (ACL) membranes made by chemical vapor deposition (CVD). The disadvantages of these membranes are the high cost of facility investment, particles generated during processing, and opaque film quality. Due to the problem of photo align due to the many inconveniences.

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

However, two properties required for such an organic hard mask layer, that is, solubility and etching resistance, are in conflict with each other, and a hard mask composition capable of satisfying all of them is required. The materials introduced into the semiconductor lithography process while satisfying the characteristics of the organic hard mask material have recently been introduced (Patent Publication 10-2009-0120827, Patent Publication 10-2008-0107210, Patent WO 2013100365 A1) And hard mask materials using a copolymer having an appropriate polymer molecular weight using hydroxypyrene.

On the other hand, recently, as the semiconductor lithography process is further miniaturized, in the case of such an organic hard mask material, it is difficult to sufficiently fulfill the role as a mask due to the lack of the etching selection ratio in the etching process compared with the existing inorganic hard mask material It was. Therefore, the introduction of an organic hard mask material more optimized for the etching process is desperately needed.

The present invention relates to a novel organic hard mask material having sufficient etching resistance and high solubility in such organic hard mask materials.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art as described above and it is an object of the present invention to provide an antireflective composition which is high in etching selectivity, resistant to multiple etching, It is an object of the present invention to provide a novel hard mask polymer which can be used to perform graphic techniques and a composition comprising the same.

According to the present invention, there is provided an aromatic ring-containing polymer comprising a spirobifluorene derivative represented by the following general formula (1).

 [Chemical Formula 1]

Wherein R is in the form of hydrogen (H) or hydroxy (-OH) and X is a co-monomer component capable of undergoing one-to-one polymerization with an aromatic ring compound mainly under acid catalyzed conditions, It is a polymeric linkage group that has the role of increasing the solubility of the formed polymer substance in the solvent. A compound having mainly aldehyde or di-methoxy or di-ethoxy group is used.

Wherein n is in the range of 1 < n < 100 and the mass average molecular weight (Mw) is between 500 and 30,000)

Also provided is an aromatic ring-containing polymer comprising a spirobifluorene derivative represented by the following formula (2).

(2)

 Wherein R is a hydrogen (H) or hydroxy (-OH) form and X is a polymeric linkage group in the above formula (1) independently of the following structure, For one-to-one polymerization, always use 50% of the total concentration.

And Y is a different type of aromatic compound having a hydrogen (H) or a hydroxyl group (OH), and is mainly introduced for improving the solubility and etch selectivity of a polymer having an overall polymer structure.

(1 + m + n) = 0.05 to 0.5, m / (l + m = n) = 0.5 and n / (l + m + n) = 0.0 to 0.45, The mass average molecular weight (Mw) of the coalescent is between 1,000 and 30,000.

On the other hand, in order to produce the hard mask composition, the above-mentioned (a) spirobenefluorene aromatic ring-containing polymer is preferably used in an amount of 1 to 30% by weight based on 100 parts by weight of the organic solvent (b) used. When the aromatic ring-containing polymer is used in an amount of less than 1 part by weight or more than 30 parts by weight, it is difficult to meet or exceed the intended coating thickness because it is less than or exceeds the desired coating thickness.

The organic solvent is not particularly limited as long as it is an organic solvent having sufficient solubility in the above aromatic ring-containing polymer. Examples thereof include propylene glycol monomethyl ether acetate (PGMEA), cyclohexanone, ethyl lactate, and the like have.

The antireflective hard mask composition of the present invention may further comprise (c) a crosslinker component; And (d) an acid catalyst.

The crosslinking agent (c) used in the hard mask 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 acid catalyst (d) It is preferably an activated acid catalyst.

The crosslinking agent component (c) used in the hard mask composition of the present invention is not particularly limited as long as it is a crosslinking agent capable of reacting with the hydroxyl group of the aromatic ring-containing polymer in such a manner as to be catalyzed by the produced acid. Specific examples thereof include etherified amino resins such as methylated or butylated melamine resins (specific examples are N-methoxymethyl-melamine resins or N-butoxymethyl-melamine resins) and methylated Urea Resin (specific examples of which are Cymel U-65 Resin or UFR 80 Resin), glycoluril derivatives (specific examples include Powderlink 1174), 2,6-bis (hydroxymethyl) p-cresol compounds and the like.

As the acid catalyst (d) used in the hard mask composition of the present invention, an organic acid such as p-toluenesulfonic acid monohydrate may be used, and a thermal acid generator (TAG) Based compounds may also be used as catalysts. TAG is an acid generator compound which is intended to release an acid upon thermal treatment, such as pyridinium P-toluene sulfonate, 2,4,4,6-tetrabromocyclohexadienone, Benzoin tosylate, 2-nitrobenzyl tosylate, and alkyl esters of organic sulfonic acids.

Therefore, when the final hard mask composition further comprises (c) a crosslinking agent component and (d) an acid catalyst, the hard mask composition of the present invention comprises (a) a spirobifluorene aromatic ring having strong absorption properties in the ultraviolet region (c) 0.1 to 5% by weight, more preferably 0.1 to 3% by weight, of a crosslinking agent component, and (d) an acid The catalyst preferably contains 0.001 to 0.05% by weight, more preferably 0.001 to 0.03% by weight of the catalyst, and (b) 75 to 98% by weight of the organic solvent.

Here, when the aromatic ring-containing polymer is less than 1% by weight or exceeds 20% by weight, it is difficult to meet or exceed the target coating thickness because it is less than or exceeds the target coating thickness.

If the content of the crosslinking agent is less than 0.1% by weight, the crosslinking property may not be exhibited. If the amount is more than 5% by weight, the optical characteristics of the coating film may be changed by excessive addition.

If the amount of the acid catalyst is less than 0.001 wt%, crosslinking properties may not be exhibited. If the amount is more than 0.05 wt%, the acidity may increase due to excessive addition, which may affect storage stability.

The antireflective hard mask composition according to the present invention has a refractive index and absorptivity in a range that is useful as an antireflective film in a Deep UV region such as ArF (193 nm) and KrF (248 nm) at the time of film formation, thereby minimizing the reflectivity between the resist and the backside layer And it is possible to provide a lithographic structure having a good pattern evaluation result because it has a high etch selectivity in a lithographic process compared to a conventional organic hard mask and has sufficient resistance against multiple etching.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

Example 1) Synthesis of spirobifluorene polymer

- 33.3 g (100 mmol) of 2-hydroxy-9,9-spirobifluorene and 11 g (100 mmol) of benzaldehyde were dissolved in 103 g of propylene glycol monomethyl ether acetate (PGMEA) in a 250 mL round flask Then, 0.07 g of p-toluenesulfonic acid monohydrate (PTSA) was added thereto.

- While maintaining the reaction temperature at about 100 ° C, the polymerization is proceeded while the molecular weight is measured using GPC in the middle of the reaction.

- After about 10 hours of reaction, the reaction mixture was dropped into an excess of methanol / water (9: 1) co-solvent. The resulting solid was dissolved again in an appropriate amount of PGMEA solvent. Excess methanol / water (9: 1) Drop into a co-solvent to catch a precipitate.

- The resulting solid was dried in a vacuum oven at about 50 ° C for about 20 hours, and a mass average molecular weight (Mw) of 3,200 was obtained.

Example 2) Synthesis of spirobifluorene polymer

- 33.3 g (100 mmol) of 2-hydroxy spirobifluorene and 17 g (100 mmol) of 1,4-bis (methoxymethyl) benzene (MBB) were dissolved in 117 g of propylene glycol monomethyl ether acetate (PGMEA) 0.07 g of toluenesulfonic acid monohydrate (PTSA) is added.

- Polymerization was carried out in the same manner as in Example 1, and the polymer was purified and dried in a vacuum oven to obtain a polymer having a weight average molecular weight of 3,100.

Example 3) Synthesis of spirobifluorene polymer

- 20 g (60 mmol) of 2-hydroxy spirobifluorene, 3.2 g (100 mmol) of paraformaldehyde and 5.8 g (40 mmol) of 1-naphthol were dissolved in 68 g of PGMEA, 0.07 g is added.

- Polymerization was carried out in the same manner as in Example 1, and the polymer was purified and dried in a vacuum oven to obtain 3,300 mass-average molecular weight polymer.

Example 4) Synthesis of spirobifluorene polymer

- (60 mmol) of 2-hydroxy spirobifluorene, 3.8 g (120 mmol) of paraformaldehyde and 11.7 g (60 mmol) of 9-hyroxyanthracene were dissolved in 83 g of PGMEA, and then PTSA 0.08 g.

- Polymerization was carried out in the same manner as in Example 1, and the polymer was purified and dried in a vacuum oven to obtain 3,500 mass average molecular weight polymer.

Example 5) Synthesis of spirobifluorene polymer

- (50 mmol) of 2-hydroxy spirobifluorene, 17 g (100 mmol) of bismethoxymethylbenzene (MBB) and 17.5 g (50 mmol) of 9,9-bis (4-hydroxyphenyl) fluorine were dissolved in 119 g of PGMEA 0.07 g of PTSA is added thereto.

- Polymerization was carried out in the same manner as in Example 1, and the polymer was purified and dried in a vacuum oven to obtain a polymer having a mass average molecular weight of 3,700.

Example 6) Synthesis of spirobifluorene polymer

- 16 g (50 mmol) of 2-hydroxy spirobifluorene, 17 g (100 mmol) of bismethoxymethylbenzene (MBB) and 9.7 g (50 mmol) of 9-hydroxyanthracene were dissolved in 101 g of PGMEA, g.

- Polymerization was carried out in the same manner as in Example 1, and the polymer was purified and dried in a vacuum oven to obtain a polymer having a weight average molecular weight of 3,800.

Example 7) Synthesis of spirobifluorene polymer

- (50 mmol) of 2-hydroxy spirobifluorene, 16.4 g (100 mmol) of 1-naphthaldehyde and 7.2 g (50 mmol) of 1-naphthol were dissolved in 94 g of PGMEA, and then PTSA 0.07 g is added.

- Polymerization was carried out in the same manner as in Example 1, and the polymer was purified and dried in a vacuum oven to obtain 3,500 mass average molecular weight polymer.

Example 8) Synthesis of spirobifluorene polymer

- 20 g (60 mmol) of 2-hydroxy spirobifluorene, 17 g (100 mmol) of bismethoxymethylbenzene (MBB) and 9.2 g (40 mmol) of triphenylene were dissolved in 108 g of PGMEA and then 0.07 g of PTSA was added thereto do.

- Polymerization was carried out in the same manner as in Example 1, and the polymer was purified and dried in a vacuum oven to obtain a polymer having a weight average molecular weight of 3,100.

Example 9) Synthesis of spirobifluorene polymer

- After dissolving 20 g (60 mmol) of 2-hydroxy spirobifluorene, 3.2 g (100 mmol) of paraformaldehyde and 8.2 g (40 mmol) of pyrene in 73 g of PGMEA, 0.07 g of PTSA was added thereto.

- Polymerization was carried out in the same manner as in Example 1, and the polymer was purified and dried in a vacuum oven to obtain a polymer having a weight average molecular weight of 3,000.

Example 10) Synthesis of spirobifluorene polymer

- (40 mmol) of 9,9-spirobifluorene, 3.2 g (100 mmol) of paraformaldehyde and 21 g (60 mmol) of 9,9-bis (4-hydroxyphenyl) fluorine were dissolved in 86 g of PGMEA, 0.07 g of PTSA is added thereto.

- Polymerization was carried out in the same manner as in Example 1, and the polymer was purified and dried in a vacuum oven to obtain 2,700 mass-average molecular weight polymer.

Comparative Example Synthesis of Hydroxynaphthalene Polymer

- 35 g (100 mmol) of 9,9-bis (4-hydroxyphenyl) fluorine and 17 g (100 mmol) of bismethoxymethylbenzene (MBB) were dissolved in 121 g of PGMEA and 0.07 g of PTSA was added thereto.

- Polymerization was carried out in the same manner as in Example 1, and the polymer was purified and dried in a vacuum oven to obtain 3,500 mass average molecular weight polymer.

Example 11) Preparation of hard mask composition

- 0.1 g of the glycoluril compound crosslinking agent (Powderlink 1174) and 1 mg of pyridinium P-toluenesulfonate were dissolved in propylene glycol monomethyl ether Acetate (PGMEA) 9 g and dissolved by filtration to prepare sample solutions of Examples 1 to 10 and Comparative Example, respectively.

- Each of the sample solutions prepared in Examples 1 to 10 and Comparative Example was spin-coated on a silicon wafer and baked at 240 DEG C for 60 seconds to form a film having a thickness of 3000 ANGSTROM.

The refractive index n and the extinction coefficient k of the formed films were respectively determined. The instrument used was an Ellipsometer (manufactured by 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 an absorbency which can be used as an antireflection film at ArF (193 nm) and KrF (248 nm) wavelengths.

Sample Type Optical properties (193 nm) Optical properties (248 nm) The refractive index (n) Absorption coefficient (k) The refractive index (n) Absorption coefficient (k) Example 1 1.51 0.69 1.71 0.47 Example 2 1.52 0.70 1.72 0.49 Example 3 1.48 0.71 1.70 0.48 Example 4 1.52 0.68 1.69 0.49 Example 5 1.51 0.70 1.72 0.47 Example 6 1.50 0.71 1.68 0.48 Example 7 1.49 0.69 1.70 0.49 Example 8 1.52 0.71 1.71 0.50 Example 9 1.53 0.73 1.73 0.53 Example 10 1.52 0.72 1.71 0.52 Comparative Example 1.44 0.70 1.97 0.27

Example 12) Lithographic evaluation of antireflective hard mask composition

- The sample solutions prepared in Examples 2, 4, 5, 6 and Comparative Example were each spin-coated on an aluminum-coated silicon wafer and baked at 240 캜 for 60 seconds to form a coating film having a thickness of 3000 Å.

- Each of the formed coating films was coated with a KrF photoresist, baked at 110 ° C for 60 seconds, exposed using ASML (XT: 1400, NA 0.93) exposure equipment, and then exposed to 2.38 wt% aqueous solution of tetramethyl ammonium hydroxide (TMAH) Each was developed for 60 seconds. Then, a line and space pattern of 90 nm was examined by using V-SEM, respectively, and the results are shown in Table 2 below. The exposure margin (margin) and the depth of focus (DoF) margin according to the variation of the distance between the light source and the light source according to the variation of the exposure amount were examined and recorded in Table 2. As a result of pattern evaluation, good results were confirmed in terms of profile and margin.

Sample Type Pattern characteristics EL margin
(? MJ / energy mJ) DoF margin
(탆) Pattern shape Example 2 0.3 0.3 cubic Example 4 0.4 0.3 cubic Example 5 0.3 0.3 cubic Example 6 0.4 0.3 cubic Comparative Example 0.1 0.1 undercut

Example 13) Evaluation of etch characteristics for anti-reflective hardmask composition

The lower SiON antireflection film (BARC) was dry-etched using the patterned specimens in Examples 4, 5 and 6 and Comparative Example as PR mask using CHF3 / CF4 mixed gas, then SiON reflection Using this protective film as a mask, dry etching of the hard mask was carried out again. After the dry etching of the silicon nitride (SiN) film with the CHF3 / CF4 mixed gas as a mask, O2 ashing and wet stripping processes were performed on the remaining hard mask and organic matter.

Immediately after hard mask etch and silicon nitride etch, the cross sections of each specimen were examined by V-SEM. As a result of the etch evaluation, after the hard mask etching and after the silicon nitride etching, the pattern shape was good without any bowing phenomenon in each case, so that the resistance against the etching process was sufficient and the etching process of the silicon nitride film was satisfactorily performed Respectively.

Sample Pattern shape (after hard mask etch) Pattern shape (after SiN etching) Example 4 Vertical shape Vertical shape Example 5 Vertical shape Vertical shape Example 6 Vertical shape Vertical shape Comparative Example Slightly Boeing appearance Boeing shape

Claims (6)

(a) a blend of a spirobifluorene derivative polymer represented by the following formula (1) and an aromatic ring-containing copolymer or other copolymer containing the same; And (b) an organic solvent.
[Chemical Formula 1]

In the above formula, R is in the form of hydrogen (H) or hydroxy (-OH), and X is mainly a polymeric linkage group. A compound having mainly aldehyde or di-methoxy or di-ethoxy group is used.

Wherein n is in the range of 1 < n < 100 and the mass average molecular weight (Mw) is between 500 and 30,000)
The antireflective hard mask composition according to claim 1, comprising an aromatic ring copolymer comprising a spirobifluorene derivative represented by the following formula (2) or a blend using the aromatic ring copolymer.
(2)

Wherein R is in the form of hydrogen (H) or hydroxy (-OH), and X is a polymeric linkage group independently of each other and has the following structure.

Y is a different type of aromatic compound having a hydrogen (H) or a hydroxyl group (OH), and has the following form.

(1 + m + n) = 0.05 to 0.5, m / (l + m = n) = 0.5 and n / (l + m + n) = 0.0 to 0.45, The mass average molecular weight (Mw) of the coalescent is between 1,000 and 30,000. The antireflective hard mask composition of claim 1, wherein the hardmask composition further comprises a crosslinker and an acid catalyst component. 4. The method of claim 3, wherein the hardmask composition comprises
(a) 1 to 20% by weight of an aromatic ring-containing copolymer or blend; (b) 0.1 to 5% by weight of a crosslinker component;
(c) 0.001 to 0.05% by weight of an acid catalyst; And
(d) an organic solvent is used as the other components, and the total amount is 100% by weight. The antireflection hard mask composition according to claim 3, wherein the cross-linking component is any one selected from the group consisting of melamine resin, amino resin, glycoluril compound, and bis-epoxy compound. 4. The process according to claim 3, wherein the acid catalyst is selected from the group consisting of p-toluenesulfonic acid monohydrate, pyridinium p-toluene sulfonate, 2,4,4,6-tetrabromosu Wherein the antistatic hard mask composition is selected from the group consisting of chlo- &lt; RTI ID = 0.0 &gt; hexadiene, &lt; / RTI &gt; benzoin tosylate, 2-nitrobenzyl tosylate and alkyl esters of organic sulfonic acids.