KR102404886B1 - A hardmask composition and polymers containing phthalocyanine derivatives - Google Patents

Abstract

The present invention provides an anti-reflective hard mask composition comprising (a) a polymer comprising a metal or non-metal phthalocyanine derivative represented by the following Chemical Formula 1 or a polymer mixture (blend) comprising the same and (b) an organic solvent.
[Formula 1]

Description

Polymer and hard mask composition comprising a phthalocyanine derivative

The present invention relates to a hardmask composition having antireflection film properties useful in a lithographic process, a polymer synthesis comprising a phthalocyanine derivative excellent in strong absorption and etch resistance in the ultraviolet wavelength region, and a hardmask composition comprising the same is about

Recently, as the semiconductor industry increasingly requires a miniaturization process, an effective lithographic process is essential to realize such ultra-fine technology. In particular, there is an increasing demand for a new material for the hard mask process, which is very essential in the etching process.

In general, the hardmask film quality serves as an intermediate film that transfers a micropattern of a photoresist to a lower substrate layer through a selective etching process. Therefore, properties such as chemical resistance, heat resistance, and etching resistance are required for the hard mask layer to withstand multiple etching processes. The previously used hardmask film quality was an amorphous carbon layer (ACL) film made by chemical vapor deposition (CVD). There were many inconveniences to use due to photo align problems.

Recently, a spin-on hardmask method of forming a spin-on coating method instead of the chemical vapor deposition method has been introduced. The spin-on coating method forms a hardmask composition using an organic polymer material having solubility in a solvent, and the most important characteristic at this time is to form an organic polymer coating film having etching resistance at the same time.

However, the properties for solubility and etching resistance, which are two properties required for the organic hardmask layer, have a conflicting relationship with each other, and a hardmask composition that can satisfy both of them was needed. Materials introduced into the semiconductor lithography process while satisfying the characteristics of these organic hardmask materials have been recently introduced (Patent Publication No. 10-2009-0120827, Patent Publication 10-2008-0107210, Patent WO 2013100365 A1), which These were hard mask materials using a copolymer having an appropriate high molecular weight synthesized by the conventional phenolic resin manufacturing method using hydroxypyrene.

However, as the semiconductor lithography process goes through more and more miniaturization in recent years, in the case of such an organic hard mask 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 hard mask material. has been reached Accordingly, there is an urgent need to introduce an organic hardmask material that is 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 comprising the same.

It is an object of the present invention to provide a novel hardmask polymer capable of minimizing the reflectivity between the resist and the backing layer, which can be used to perform lithographic techniques, and a composition comprising the same.

A hard mask composition according to the present invention, (a) a polymer represented by the following formula (1), including a phthalocyanine derivative (MPc) or a mixture of these polymers (blend); and (b) an organic solvent; It is an anti-reflection hard mask composition comprising a.

[Formula 1]

The hardmask composition based on the copolymer containing the phthalocyanine derivative (MPc) according to the present invention has a very high carbon content in the polymer, which is very advantageous for etch resistance, and at the same time has excellent polymer solubility, which is very advantageous for uniform thin film formation. Accordingly, it is possible to provide a lithographic structure having an excellent pattern evaluation result because the etch selectivity ratio is high compared to the conventional organic hardmask, and the resistance to multiple etching is sufficient.

The hard mask composition based on a copolymer containing a phthalocyanine derivative (MPc) according to embodiments of the present invention has a refractive index in a useful range as an anti-reflection film in the deep UV region such as ArF (193 nm), KrF (248 nm), etc. when forming a film, and By having the absorbance, it is possible to minimize the reflectivity between the resist and the back surface layer.

According to the present invention, a polymer comprising a phthalocyanine derivative (MPc) represented by the following formula (1) or a mixture of these polymers; and

(b) an organic solvent; An anti-reflective hard mask composition comprising a.

[Formula 1]

In the above formula, Ar is a C6-C30 aryl group or heteroaryl group, and X is hydrogen, or at least one hydroxy group or an alkoxy group.

R1 and R2 are hydrogen or a C1~C10 alkyl group, a C2~C10 alkenyl group, a C6~C20 aryl group and a heteroaryl group, and a C6~C20 aryl group which may be substituted with a hydroxyl group, a fluorine group, or a nitrile group . Here, R1 and R2 may form a ring together with the carbon atom to which they are attached.

In the above formula, the MPc structure represents a metal or non-metal phthalocyanine derivative, and a copolymer can be synthesized by a novolak polymerization method with aromatic monomers serving as electron-donors.

The phthalocyanine derivative (MPc) has the same structure as the following formula (2).

[Formula 2]

In the above formula, M is 2H, Si, a metal, an oxymetal group, a hydroxy metal group or a halo metal group, more preferably 2H or a metal (Zn, Cu, Ti, Co, Ni, Sn, Fe, Pt, Pb, Mg) and one selected from the group consisting of oxides of these metals. where n is 0 or 1.

And, R3 and R4 are hydrogen, C1-C20 alkyl, alkoxy, or sulfonic acid or carboxylic acid, and may be the same as or different from each other.

Here, the molar ratio of each monomer is p/(p+q+r)=0.1 to 0.5, q/(p+q+r)=0.4 to 0.6, and r/(p+q+r)=0.001 to 0.3. have a range

On the other hand, the weight average molecular weight (Mw) of the entire copolymer is 1,000 to 50,000, and preferably has a range between 2,000 to 20,000.

The polymer having the structure of Formula 1 may have, for example, the following (Formula 2-1) to (Formula 2-21).

The polymers may be further mixed with a novolak resin or an aromatic C6 to C20 novolak polymer having a hydroxyl group to improve dissolution properties, coating properties, or curing properties of the entire hardmask composition.

On the other hand, in order to make a hard mask composition, the copolymer including the phthalocyanine derivative (MPc) of (a) or a mixture of these copolymers is added to 100 parts by weight of the total composition. It is preferably used in an amount of 1 to 30% by weight. When the 'polymer or mixture' of (a) is used in less than 1 part by weight or in excess of 30 parts by weight, it becomes less than or exceeds the desired coating thickness, so it is difficult to accurately match the coating thickness.

And the organic solvent is used in an amount excluding the amount of other constituents of the composition out of 100 parts by weight of the total composition, and the organic solvent is not particularly limited as long as it has sufficient solubility for the above aromatic ring-containing polymer, for example Examples thereof include propylene glycol monomethyl ether acetate (PGMEA), cyclohexanone, ethyl lactate, and gamma butyrolactone (GBL).

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

It is preferable that the crosslinking agent component (c) used in the hardmask composition of the present invention can crosslink the repeating unit of the polymer by heating in a catalytic reaction by the generated acid, and the (d) acid catalyst is thermally activated It is preferably an acid catalyst.

The crosslinking agent component (c) used in the hardmask composition of the present invention is not particularly limited as long as it is a crosslinking agent that can be reacted with the aromatic ring-containing polymer in a manner that can be catalyzed by the produced acid. Examples of the crosslinking agent include a melamine-based, substituted urea-based, or polymer-based crosslinking agent. Preferably it is a crosslinking agent having at least two crosslinking substituents, methoxymethylated glycoluril, butoxymethyl glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxymethylated benzoguanamine; A compound such as methoxymethylated urea, butoxymethylated urea, and methoxymethylated thiourea.

In addition, although a crosslinking agent with high heat resistance can be used as the crosslinking agent, a compound containing a crosslinking substituent having an aromatic ring in its molecule can be preferably used. These compounds may be exemplified by compounds having the following structural formulas.

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) that promotes storage stability A systemic compound can also be used as a catalyst. TAG is an acid generator compound adapted to release an acid upon 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, and the like.

When the final hardmask composition further comprises (c) a crosslinking agent component and (d) an acid catalyst, the hardmask composition of the present invention includes (a) a phthalocyanine derivative (MPc) having strong absorption properties in the ultraviolet region. 1 to 30% by weight, more preferably 5 to 20% by weight of the copolymer or a mixture of these copolymers, (c) 0.1 to 5% by weight of the crosslinking agent component, more preferably 0.1 to 3% by weight, (d) ) acid catalyst 0.001 to 0.05% by weight, more preferably 0.001 to 0.03% by weight, and (b) may consist of a total of 100% by weight using an organic solvent as the remaining component, preferably 75 to 98% by weight of organic solvent It is preferable to contain

Here, when the copolymer including the phthalocyanine derivative (MPc) is less than 1% by weight or exceeds 30% by weight, it becomes less than or exceeds the desired coating thickness, so it is difficult to accurately match the coating thickness.

And 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 due to excessive input.

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

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

Example-1) Synthesis of copolymer

9,9-bishydroxyphenyl fluorene (50 mmol), benzaldehyde (55 mmol), and phthalocyanine (2 mmol) were completely dissolved in the solvent gamma-butyrolactone (GBL) (total monomer weight X 3 times), and then 5 mol% of sulfuric acid was added After addition, polymerization was carried out at a temperature of 125°C for about 20 hours.

After polymerization, the reactants are precipitated in an excess of methanol/water (8:2) solvent, and then neutralized using triethylamine. The resulting precipitate was filtered, washed twice with an excess of methanol solution, and the precipitate was filtered and dried in a vacuum oven at 80°C for 24 hours to obtain the polymer.

At this time, a high molecular weight average molecular weight (Mw) of 4,400 and polydispersity (Mw/Mn) of 1.85 were obtained.

Example-2) Synthesis of copolymer

9,9-bishydroxyphenyl fluorene (50 mmol), benzaldehyde (55 mmol), and tin (tin) phthalocyanine (2 mmol) were synthesized in the same manner as in Example 1 to obtain the polymer. At this time, the synthesized polymer had a weight average molecular weight (Mw) of 4,800 and a polydispersity (Mw/Mn) of 1.84.

Example-3) Synthesis of copolymer

9,9-bishydroxyphenyl fluorene (50 mmol), benzaldehyde (55 mmol), and titanyl phthalocyanine (2 mmol) were synthesized in the same manner as in Example 1 to obtain the polymer. At this time, the synthesized polymer had a weight average molecular weight (Mw) of 4,300 and a polydispersity (Mw/Mn) of 1.89.

Example-4) Synthesis of copolymer

Indole (50 mmol), benzaldehyde (55 mmol), and phthalocyanine (3 mmol) were synthesized in the same manner as in Example-1 to obtain the polymer. At this time, the synthesized polymer had a weight average molecular weight (Mw) of 5,900 and polydispersity (Mw/Mn) of 1.87.

Example-5) Synthesis of copolymer

Indole (50 mmol), 2-naphthylaldehyde (55 mmol), and phthalocyanine (3 mmol) were synthesized in the same manner as in Example 1 to obtain the polymer. At this time, the synthesized polymer had a weight average molecular weight (Mw) of 4,700 and a polydispersity (Mw/Mn) of 1.88.

Example-6) Synthesis of copolymer

Indole (50 mmol), flurenone (55 mmol), and phthalocyanine (3 mmol) were synthesized in the same manner as in Example-1 to obtain the polymer. At this time, the synthesized polymer had a weight average molecular weight (Mw) of 4,500 and a polydispersity (Mw/Mn) of 1.87.

Example-7) Synthesis of copolymer

Indole (50 mmol), flurenone (55 mmol), and tinphthalocyanine (2 mmol) were synthesized in the same manner as in Example-1 to obtain the polymer. At this time, the synthesized polymer had a weight average molecular weight (Mw) of 4,300 and a polydispersity (Mw/Mn) of 1.86.

Example-8) Synthesis of copolymer

Indole (50 mmol), flurenone (55 mmol), and cobalt phthalocyanine (2 mmol) were synthesized in the same manner as in Example-1 to obtain the polymer. At this time, the synthesized polymer had a weight average molecular weight (Mw) of 4,600 and a polydispersity (Mw/Mn) of 1.87.

Example-9) Synthesis of copolymer

1-Pyrenol (50 mmol), flurenone (55 mmol), and phthalocyanine (2 mmol) were synthesized in the same manner as in Example-1 to obtain the polymer. At this time, the synthesized polymer had a weight average molecular weight (Mw) of 4,100 and a polydispersity (Mw/Mn) of 1.88.

Example-10) Synthesis of copolymer

9,9-bishydroxynaphthylfluorene (50 mmol), benzaldehyde (55 mmol), and phthalocyanine (2 mmol) were synthesized in the same manner as in Example 1 to obtain the polymer. At this time, the synthesized polymer had a weight average molecular weight (Mw) of 3,900 and a polydispersity (Mw/Mn) of 1.88.

Example-11) Synthesis of copolymer

Indole (50 mmol), flurenone (55 mmol), and 2,3-naphthalocyanine (2 mmol) were synthesized in the same manner as in Example-1 to obtain the polymer. At this time, the synthesized polymer had a weight average molecular weight (Mw) of 3,500 and a polydispersity (Mw/Mn) of 1.88.

Example-12) Synthesis of copolymer

Indole (50 mmol), flurenone (55 mmol), and 2,11,20,29-tetra-t-butyl-2,3-naphthalocyanine (2 mmol) were synthesized in the same manner as in Example-1 to obtain the polymer. At this time, the synthesized polymer had a weight average molecular weight (Mw) of 4,100 and a polydispersity (Mw/Mn) of 1.88.

Comparative Example) Synthesis of Phenolic Copolymer

After dissolving 9,9-bishydroxyphenylfluorene (100 mmol) and benzaldehyde (110 mmol) in PGMEA, 5 mol% of concentrated sulfuric acid is added thereto.

After polymerization in the same manner as in Example-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.

Hard mask composition preparation

1 g of the polymer prepared in Examples 1 to 12 and Comparative Examples and 300 ppm of surfactant (relative to the weight ratio of the polymer) were put in 7 g of propylene glycol monomethyl ether acetate and 3 g of cyclohexanone and completely dissolved, and then filtered using a 0.1 um Melbrain filter. Examples 1 to 12 and Comparative Examples sample solutions were prepared, respectively.

Each of the sample solutions prepared in Examples 1 to 12 and Comparative Example was spin-coated on a silicon wafer and baked at 400° C. for 120 seconds to form a film having a thickness of 3000 Å.

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

As a result of the evaluation, it was confirmed that there was a refractive index and absorbance usable as an antireflection film at ArF (193 nm) and KrF (248 nm) wavelengths. Generally, the refractive index range of the material used as a semiconductor anti-reflection film is about 1.4 to 1.8, and the important thing is the extinction coefficient, and the higher the absorbance, the better. It can be seen that the hard mask composition according to the embodiments can be used as an anti-reflection film.

sample type Optical Characteristics (193nm) Optical Characteristics (248nm) refractive index (n) extinction coefficient (k) refractive index (n) extinction coefficient (k) Example 1 1.52 0.56 1.70 0.53 Example 2 1.55 0.61 1.73 0.54 Example 3 1.51 0.60 1.72 0.55 Example 4 1.55 0.63 1.73 0.58 Example 5 1.55 0.68 1.74 0.61 Example 6 1.54 0.61 1.72 0.54 Example 7 1.56 0.61 1.73 0.54 Example 8 1.55 0.60 1.71 0.55 Example 9 1.54 0.63 1.72 0.54 Example 10 1.52 0.61 1.70 0.56 Example 11 1.53 0.64 1.72 0.55 Example 12 1.54 0.65 1.71 0.53 Comparative Example 1.48 0.51 1.95 0.35

Lithographic evaluation of antireflective hardmask compositions

The sample solutions prepared in Examples 1, 4, 6, 9 and Comparative 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.

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

sample type pattern characteristics EL margin
(ΔmJ/energy mJ) DoF margin
(μm) pattern shape Example 1 0.3 0.3 cubic Example 4 0.4 0.3 cubic Example 6 0.4 0.4 cubic Example 9 0.4 0.4 cubic Comparative Preparation Example 0.2 0.2 undercut

Evaluation of etching properties for anti-reflective hardmask compositions

/s)를 계산하였다. 그 결과는 아래와 표3과 같다. After forming a thin film by heat-treating the hard mask compositions (10% by weight) according to Examples 1 to 12 and Comparative Examples at a temperature of 400 degrees for 120 seconds, respectively, a N2/O2 mixed gas (50mT/ 300W/10 O2/ 50 N2 conditions) and CFx gas (100 mT/600W/42 CF4/600 Ar/15 O2 conditions) for 60 seconds, and then the thickness of the thin film was measured before and after etching. Each etch rate (

/s) was calculated. The results are shown in Table 3 below.

Sample

/s)N2/O2 etch(

/s) CFx etch(

/s) Example 1 34.5 23.7 Example 4 34.6 22.4 Example 6 34.7 22.0 Example 7 32.5 20.5 Example 9 34.2 22.1 Example 10 34.8 22.3 Example 11 32.8 19.7 Comparative Example 36.2 35.5

As shown in Table 3, the thin film formed in the above example shows very good etching resistance compared to the thin film formed in the comparative example, and the hard mask composition prepared in the above example forms a lithography pattern based on such bulk etch characteristics. It is expected that it can serve as a very good anti-reflection hard mask.

Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention defined in the following claims are also presented. It belongs to the scope of the right of the invention.

Claims (7)

delete A polymer comprising a phthalocyanine derivative (MPc) represented by the following formula (1).
[Formula 1]

In the above formula, Ar is a C6-C30 aryl group or a C6-C30 heteroaryl group, and X is hydrogen, one or more hydroxy groups, or an alkoxy group.
R1 and R2 are each hydrogen, a C1~ C10 alkyl group, a C2~ C10 alkenyl group, a C6~ C20 aryl group, or a C6~ C20 heteroaryl group, and the C6~ C20 aryl group is a hydroxyl group, fluorine, or It may be substituted with a nitrile group. Here, R1 and R2 may form a ring together with the carbon atom to which they are attached.
In the above formula, the MPc structure represents a metal or non-metal phthalocyanine derivative, and has the structure of Formula 2 below.
[Formula 2]

In the above formula, M is one selected from the group consisting of 2H, a metal, and an oxide of the metal, and the metal is Zn, Cu, Ti, Co, Ni, Sn, Fe, Pt, Pb, Mg or Si. where n is 0 or 1.
R3 and R4 are each hydrogen, C1-C20 alkyl, alkoxy, sulfonic acid, or carboxylic acid, and may be the same as or different from each other.
Here, the molar ratio of each monomer is p/(p+q+r)=0.1~0.5, q/(p+q+r)=0.4~0.6, r/(p+q+r)=0.001~0.3 have a range between 3. The method of claim 2,
X is a hydroxyl group,
Polymer, characterized in that the Ar group has a naphthalene, bisnaphthalene, pyrene, carbazole, indole, or fullerene derivative structure. 3. The method of claim 2,
A polymer, characterized in that it has a phthalocyanine derivative structure in which M is 2H in MPc. 3. The method of claim 2,
In MPc, M is Zn, Cu, Ti, Co, Ni, Sn, Fe, Pt, Pb, Mg, or Si, characterized in that it has a metal phthalocyanine derivative structure. (a) the polymer according to any one of claims 2 to 5 or a blend of these polymers; and
(b) an organic solvent; anti-reflective hard mask composition comprising a. 7. The method of claim 6,
The hardmask composition further comprises an anti-reflective hardmask composition comprising a crosslinking agent and an acid catalyst component.