KR102583217B1 - A composition of anti-reflective hardmask - Google Patents

Abstract

The present invention relates to a hard mask composition having anti-reflection properties useful for lithographic processes, and is an aromatic ring containing an organometal that exhibits strong absorption in the ultraviolet wavelength range and is relatively transparent in the visible range. (aromatic ring) polymer and a hard mask composition comprising the same.

Description

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

The present invention relates to a hard mask composition having anti-reflection properties useful for lithographic processes, and is an aromatic ring containing an organometal that exhibits strong absorption in the ultraviolet wavelength range and is relatively transparent in the visible range. (aromatic ring) polymer and a hard mask composition comprising the same.

Recently, as the semiconductor industry has increasingly required miniaturization processes, an effective lithographic process is essential to realize such ultra-fine technologies. In particular, the demand for new materials for the hard mask process, which is very essential in the etching process, is increasing.

In general, the hard mask layer serves as an intermediate layer that transfers the fine pattern of the photoresist to the lower substrate layer through a selective etching process. Therefore, the hard mask film requires properties such as chemical resistance, heat resistance, and etching resistance to withstand multiple etching processes. The hard mask film used previously used an ACL (amorphous carbon layer) film made by chemical vapor deposition (CVD), but its disadvantages include high equipment investment, particles generated during the process, and opacity of the film. It was very inconvenient to use due to problems such as photo misalignment.

Recently, a spin-on hardmask method formed by a spin-on coating method was introduced instead of this chemical vapor deposition method. The spin-on coating method forms a hard mask composition using an organic polymer material that is soluble in a solvent, and the most important characteristic at this time is the formation of an organic polymer coating film that simultaneously has etching resistance.

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

However, as the semiconductor lithographic process has recently gone through a process of further miniaturization, it has become difficult for these organic hard mask materials to sufficiently perform the role of a mask due to the lack of etching selectivity in the etching process compared to existing inorganic hard mask materials. It has arrived.

In addition, as the thickness of the organic hard mask film gradually increases, it appears opaque in the photo alignment process using the 633nm wavelength, so there are two

There was a limit to increasing the power.

Therefore, there is an urgent need to introduce a hardmask material that is more transparent in the 633nm region compared to existing hardmask materials and at the same time can exhibit a higher selectivity in the etching process.

Domestic Patent Publication No. 10-2011-0053136 (2011.05.19.)

The purpose of the present invention is to provide an organic metal hardmask polymer with excellent polymer solubility and a composition containing the same.

The purpose of the present invention is to provide an organometallic hardmask polymer that has high etching selectivity and sufficient resistance to multi-etching, and a composition containing the same.

The purpose of the present invention is to provide an organic metal hardmask polymer that can minimize reflectivity between the resist and the back layer and a composition containing the same.

The hard mask composition according to embodiments of the present invention includes an organic molecule having a hydroxy group in the backbone or side chain as a monomer, and a polymer in which the hydroxy group is partially substituted with a metal or metalloid.

The hardmask composition according to embodiments of the present invention

(a) a polymer consisting only of an organometallic aromatic compound represented by the following formula (1) or a polymer blend containing the polymer; and

(b) organic solvent; includes.

[Formula 1]

In Formula 1, R1, R2, and R3 are each C1~C10 alkyl, C1~C10 alkoxy, C2~C10 alkenyl, and C6~C20 aryl. It is one selected from the group consisting of

R1, R2, and R3 may each be the same or different from each other,

M is a metal or metalloid of group 14, 13, 10, or 4,

R4 and R5 are any one selected from hydrogen (H), C1~C10 alkyl, C2~C10 alkenyl, and C6~C40 aryl group, and R4 and R5 are the same. It may be different,

A is an aryl group of C6 to C40, and may be substituted or unsubstituted with a halogen group, nitro group, amino group, formyl group, carboxyl group, or hydroxyl group, and may contain or not contain an ether bond, a ketone bond, or an ester bond, ,

n = 2 or more,

The weight average molecular weight (Mw) of the polymer is 1,000 to 30,000.

The hard mask composition based on the organometallic aromatic polymer according to embodiments of the present invention can produce a stable polymer by reacting a metal or metalloid compound with an existing novolak-based polymer.

The hardmask composition based on the organometallic polymer according to embodiments of the present invention has an excellent etch barrier function caused by metal or metalloid components, resulting in excellent etch resistance of the overall hardmask thin film. Therefore, it is possible to provide a lithographic structure with excellent pattern evaluation results due to its high etching selectivity compared to existing organic hard masks and sufficient resistance to multiple etchings.

The hard mask composition based on an organic metal aromatic polymer according to embodiments of the present invention has a refractive index and absorbance in a useful range as an anti-reflection film in the deep UV region such as ArF (193 nm) and KrF (248 nm) when forming a film, thereby forming a resist. Reflectivity between the and the back layer can be minimized.

Additionally, it is suitable for realizing a relatively high thickness organic hard mask process by providing a more transparent film quality in the photo alignment process.

Anti-reflective hardmask compositions according to embodiments include a polymer that includes an organic molecule having a hydroxyl group in the backbone or side chain as a monomer, and the hydroxyl group is partially substituted with a metal or metalloid.

The metal or metalloid may be selected from metals or metalloids that can exhibit excellent selectivity during the etching process. The metal or metalloid may be a Group 14, Group 13, Group 10, or Group 4 metal or metalloid.

In the case of a group 14 metalloid, it may be silicon (Si) or germanium (Ge), but is not limited thereto.

In the case of a group 14 metal, it may be tin (Sn), but is not limited thereto.

In the case of a group 13 metalloid (B), it may be boron (B), but is not limited thereto.

In the case of a group 13 metal, it may be aluminum (Al), but is not limited thereto.

In the case of a group 10 metal, it may be nickel (Ni), but is not limited thereto.

In the case of a group 4 metal, it may be titanium (Ti), but is not limited thereto.

High molecular weight polymers with partially substituted metalloid atoms may be more desirable for anti-reflective hardmask compositions. In the case of metal, it shows a very good selectivity during the etching process, but conversely, contamination problems may occur due to particles of metal components. Therefore, metalloid components may be more preferable as they are free from particle contamination problems.

In addition, among metalloid components, substances that can be easily removed under halogen (Cl2, CFx)-based etching gas conditions in the ashing process after the etching process

This may be more desirable. Therefore, the metalloid may be group 14 germanium, etc.

The organic molecule having a hydroxy group in the backbone or side chain may be 1-naphthol, 1-pyrenol, or 9,9-bishydroxyphenylfluorene.

According to embodiments, the anti-reflective hardmask composition includes (a) a polymer consisting only of an organometallic aromatic compound represented by the following formula (1) or a polymer blend containing the polymer; and (b) an organic solvent.

[Formula 1]

In Formula 1, R1, R2, and R3 are each C1~C10 alkyl, C1~C10 alkoxy, C2~C10 alkenyl, and C6~C20 aryl. It is one selected from the group consisting of

R1, R2, and R3 may each be the same or different from each other,

M is a metal or metalloid of group 14, 13, 10, or 4,

R4 and R5 are any one selected from hydrogen (H), C1~C10 alkyl, C2~C10 alkenyl, and C6~C40 aryl group, and R4 and R5 are the same. It may be different,

A is an aryl group of C6 to C40, and may be substituted or unsubstituted with a halogen group, nitro group, amino group, formyl group, carboxyl group, or hydroxyl group, and may or may not include an ether bond, a ketone bond, or an ester bond. There is,

n = 2 or more,

The weight average molecular weight (Mw) of the polymer may be 1,000 to 30,000, and preferably the weight average molecular weight (Mw) of the polymer may be 2,000 to 10,000.

Specifically in the above equation,

The M may be a group 14 metalloid.

M may be a group 14 metal.

The R1, R2, and R3 may each be selected from the group consisting of a C1~C10 alkyl group or a C6~C20 aryl group.

R4 and R5 may each be selected from the group consisting of hydrogen, phenyl(?), bismethylbenzene, biphenyl, and phenoxyphenyl.

A may be naphthalene, pyrene or hydroxyphenylfluorene.

In order to make an anti-reflective hard mask composition, it is preferable that (a) the organic metal polymer is used in an amount of 1 to 30% by weight based on 100 parts by weight of the organic solvent (b) used. If the organometallic polymer is used in less than 1 part by weight or more than 30 parts by weight, the desired coating thickness falls below or exceeds the desired coating thickness, making it difficult to achieve an accurate coating thickness.

The organic solvent is not particularly limited as long as it has sufficient solubility for the above organic metal aromatic ring-containing polymer. For example, propylene glycol monomethyl ether acetate (PGMEA), cyclohexanone, ethyl lactate, etc. I can hear it.

In addition, the anti-reflective 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 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 (d) acid catalyst is heat-activated. It is preferred that it is an acid catalyst that is activated.

The cross-linking agent component (c) used in the hard mask composition of the present invention is specifically limited as long as it is a cross-linking agent that can react with the reactive group (e.g., hydroxy group) of the aromatic ring-containing polymer in a manner that can be catalyzed by the produced acid. It doesn't work. Specific examples of this include etherified amino resins, such as methylated or butylated melamine resins (specific examples include N-methoxymethyl-melamine resin or N-butoxymethyl-melamine resin) and methylated amino resins. or butylated urea resin (specific examples, Cymel U-65 Resin or UFR 80 Resin), glycoluryl compounds (specific examples, Powderlink 1174), or bisepoxy compounds (specific examples, 2 , 6-bis(hydroxymethyl)-p*?*cresol compound), etc. can be mentioned as examples.

The (d) acid catalyst used in the hard mask composition of the present invention may be an organic acid such as p-toluenesulfonic acid monohydrate, and TAG (Thermal Acid Generator) for storage stability. Chemical compounds can also be used as catalysts. TAG is an acid generator compound that releases acid upon heat treatment, such as 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.

In the case where the final hardmask composition further includes (c) a crosslinking agent component and (d) an acid catalyst, the hardmask composition of the present invention is (a) a polymer made of an organometallic aromatic compound with strong absorption characteristics in the ultraviolet region, or It may include 1 to 30% by weight of a polymer blend containing it, (c) 0.1 to 5% by weight of a crosslinker component, (d) 0.001 to 0.05% by weight of an acid catalyst, and (b) the remaining amount of the organic solvent. . Here, if the polymer made of the organometallic aromatic compound or the polymer blend containing the same is less than 1% by weight or exceeds 30% by weight, the desired coating thickness falls below or exceeds the desired coating thickness, making it difficult to achieve an accurate coating thickness. A polymer made of an organometallic aromatic compound or a polymer mixture containing it may be used in an amount of 3% to 15% by weight.

In addition, if the crosslinking agent component is less than 0.1% by weight, crosslinking characteristics may not appear, and if it exceeds 5% by weight, the optical properties of the coating film may be changed due to excessive addition. The crosslinking agent component may be used in an amount of 0.1 to 3% by weight.

In addition, if the acid catalyst is less than 0.001% by weight, crosslinking characteristics may not appear well, and if it is more than 0.05% by weight, storage stability may be affected due to an increase in acidity due to excessive addition. The acid catalyst may be used in an amount of 0.001 to 0.03% by weight.

And the organic solvent can be used in an amount of 75 to 98% by weight.

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

Manufacturing Example 1)

In a round flask, 14.5 g (100 mmol) of 1-naphthol and 3.3 g (110 mmol) of paraformaldehyde were dissolved in 45 g (2.5 times the monomer) of propylene glycol monomethyl ether acetate (PGMEA), then the temperature was raised. Heat to about 60 degrees and melt cleanly for about 15 minutes.

A catalytic amount (2-5 mol%) of concentrated sulfuric acid is added here, and polymerization is performed for about 4-10 hours depending on the temperature while maintaining the reaction temperature at 100-130 degrees.

After polymerization is completed, the reactant is dropped into an excess of methanol/water (7:3) co-solvent and then neutralized using triethylamine (TEA).

After dissolving the precipitate in an appropriate amount of THF solvent, add an appropriate amount of pyridine and dissolve it cleanly, then add 20-80 mol% of 1-naphthol to partially replace triphenylgermanium chloride. After slowly adding the amount, the reaction temperature is 60 degrees for about 4 hours.

After the reaction is over, the reactant is dropped into an excess of water, the resulting precipitate is caught, dissolved again in an appropriate amount of THF solvent, and then reprecipitated using an excess amount of methanol. The resulting precipitate was filtered and dried in a vacuum oven at 50 degrees for about 20 hours, and then a polymer with a weight average molecular weight (Mw) of 4,100 was obtained.

Manufacturing Example 2)

14.5 g (100 mmol) of 1-naphthol and 12 g (110 mmol) of benzaldehyde were dissolved in 66 g of PGMEA solvent, and then the polymer was synthesized in the same manner as Preparation Example 1.

A polymer in which the germanium (Ge) element was partially substituted was finally synthesized using an appropriate amount of triphenylgermanium chloride in the presence of pyridine. After polymer purification, a polymer with a weight average molecular weight (Mw) of 3,500 was obtained.

Manufacturing example 3)

22 g (100 mmol) of 1-pyrenol and 3.3 g (110 mmol) of paraformaldehyde were dissolved in 65 g of PGMEA solvent, then the polymer was synthesized in the same manner as Preparation Example 1, and then triphenyl germanium chloride was added. The final polymer was synthesized by partial substitution. After polymer purification, a polymer with a weight average molecular weight (Mw) of 3,700 was obtained.

Manufacturing example 4)

22 g (100 mmol) of 1-pyrenol and 18.3 g (110 mmol) of 1,4-bis(methoxymethyl) benzene were dissolved in PGMEA solvent, and then polymerized in the same manner as Preparation Example 1. After synthesis, the final polymer was synthesized by partial substitution of triphenylgermanium chloride. After polymer purification, a polymer with a weight average molecular weight (Mw) of 3,600 was obtained.

Manufacturing Example 5)

35 g (100 mmol) of 9,9-Bis(4-hydroxyphenyl)fluorene} and 13 g (120 mmol) of benzaldehyde were dissolved in PGMEA solvent, and then the polymer was prepared in the same manner as Preparation Example 1. After synthesis, the final polymer was synthesized by partial substitution of triphenyl germanium chloride. After polymer purification, a polymer with a weight average molecular weight (Mw) of 4,100 was obtained.

Manufacturing example 6)

18 g (50 mmol) of 9,9-bishydroxyphenylfluorene and 11 g (60 mmol) of biphenyl-aldehyde were dissolved in PGMEA solvent, and then the polymer was synthesized in the same manner as Preparation Example 1, and triphenyl The final polymer was synthesized by partial substitution of germanium chloride. After polymer purification, a polymer with a weight average molecular weight (Mw) of 3,900 was obtained.

Manufacturing example 7)

18 g (50 mmol) of 9,9-bishydroxyphenylfluorene and 12 g (60 mmol) of 4-phenoxybenzaldehyde were dissolved in PGMEA solvent, and then the polymer was synthesized in the same manner as in Preparation Example 1. The final polymer was synthesized by partial substitution of triphenylgermanium chloride. After polymer purification, a polymer with a weight average molecular weight (Mw) of 4,300 was obtained.

Manufacturing example 8)

22 g (100 mmol) of 1-pyrenol and 3.3 g (110 mmol) of paraformaldehyde were dissolved in PGMEA solvent, then the polymer was synthesized in the same manner as Preparation Example 1, and then partially substituted with triphenyltin chloride. The final polymer was synthesized. After polymer purification, a polymer with a weight average molecular weight (Mw) of 3,900 was obtained.

Manufacturing Example 9)

36 g (100 mmol) of 9,9-bishydroxyphenylfluorene and 13 g (120 mmol) of benzaldehyde were dissolved in PGMEA solvent, then the polymer was synthesized in the same manner as Preparation Example 1, and then trimethyltin chloride was added. The final polymer was synthesized by partial substitution. After polymer purification, a polymer with a weight average molecular weight (Mw) of 3,300 was obtained.

Manufacturing Example 10)

36 g (100 mmol) of 9,9-bishydroxyphenylfluorene and 13 g (120 mmol) of benzaldehyde were dissolved in PGMEA solvent, then the polymer was synthesized in the same manner as Preparation Example 1, and then chlorotriethoxysilane was added. The final polymer was synthesized by partial substitution. After polymer purification, a polymer with a weight average molecular weight (Mw) of 3,500 was obtained.

Comparative manufacturing example) Synthesis of phenol novolac derivative polymer

Dissolve 35 g (100 mmol) of 9,9-bishydroxyphenylfluorene (BPF) and 12.7 g (120 mmol) of benzaldehyde in 115 g of PGMEA, then add 1 g of concentrated sulfuric acid.

After reacting at a reaction temperature of 120 degrees for about 10 hours, the reactant is dropped into an excess of methanol/water (7/3) co-solvent to precipitate, and then neutralized using triethylamine.

The precipitate was dissolved in an appropriate amount of THF, reprecipitated in an excess of methanol/water (9/1), and then hung and dried in an oven to obtain a polymer with a weight average molecular weight of 3,300.

Manufacture of anti-reflective hard mask composition

Weigh 0.9 g of each polymer made in Preparation Examples 1 to 10 and Comparative Preparation Examples, and mix 0.1 g of glycoluryl compound crosslinking agent (Powderlink 1174) and 1 mg of pyridinium P-toluene sulfonate with propylene glycol monomethyl. It was dissolved in 9 g of ether acetate (PGMEA) and filtered to prepare a composition solution composed of the polymers of Preparation Examples 1 to 10 and a composition solution composed of the polymers of Comparative Preparation Examples, respectively.

Measurement of refractive index and extinction coefficient of hard mask composition

The hard mask composition solution composed of the polymer of Preparation Examples 1 to 10 and the hard mask composition solution composed of the polymer of Comparative Preparation Example were spin-coated on a silicon wafer and baked at 240°C for 60 seconds to form a film with a thickness of 3000 Å. The films formed at this time were: The refractive index n and extinction coefficient k were obtained respectively. The device used was 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 absorption that could be used as an anti-reflection film at ArF (193 nm) and KrF (248 nm) wavelengths. Typically, the polymer synthesized in the comparative preparation example shows a relatively high transmittance in the 633 nm region, but it can be seen that the hard mask composition according to the preparation examples of the present invention shows a relatively low absorption rate compared to the polymer of the comparative preparation example. It can be seen that it can be used as a very transparent anti-reflection film in the 633nm region.

Lithographic evaluation of anti-reflective hardmask compositions

A hard mask composition was formed using the polymers of Preparation Examples 1, 3, 5, and 7 and the polymer of Comparative Preparation Example in the same manner as the hard mask composition forming method described above.

Next, the hard mask composition was spin-coated on each aluminum-coated silicon wafer and baked at 400°C for 90 seconds to form an anti-reflective hard mask film with a thickness of 3000 Å.

KrF photoresist was coated on each anti-reflective hard mask film formed, baked at 110°C for 60 seconds, exposed using ASML (XT: 1400, NA 0.93) exposure equipment, and TMAH (tetramethyl ammonium hydroxide) 2.38. Each was developed for 60 seconds with a wt% aqueous solution. 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 (expose latitude) margin according to changes in exposure amount and the DoF (depth of focus) margin according to changes in 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 litho pattern evaluation were satisfied.

Evaluation of etching properties for anti-reflective hardmask compositions

An anti-reflection hard mask film made of a hard mask composition containing the polymers of Preparation Examples 3, 5, and 6 and the polymer of Comparative Preparation Examples was formed on the wafer on which the silicon nitride film was formed, a SiON anti-reflection film was formed thereon, and a KrF Photoresist was coated, baked at 110°C for 60 seconds, each exposed using exposure equipment from ASML (XT: 1400, NA 0.93), and each was developed for 60 seconds with a 2.38wt% aqueous solution of TMAH (tetramethyl ammonium hydroxide).

Next, the lower SiON anti-reflective film (BARC) was dry-etched using the patterned PR as a mask using a CHF3/CF4 mixed gas, and then an anti-reflective hard mask film was created using the SiON anti-reflective film as a mask using an O2/N2 mixed gas. A hard mask was formed by etching.

Afterwards, the silicon nitride (SiN) film was dry-etched using a hard mask as a mask using a CHF3/CF4 mixed gas, and then O2 ashing and wet strip processes were performed on the remaining hard mask and organic materials. .

Immediately after hardmask etching and silicon nitride etching, cross-sections of each specimen were examined using V-SEM, and the results are listed in Table 3.

As a result of the etching evaluation, the pattern shapes after the hard mask etching and the silicon nitride etching were all good with no bowing phenomenon in each case, and the resistance to the etching process was sufficient, so the etching process of the silicon nitride film was performed well. confirmed.

Claims (9)

(a) a polymer consisting only of an organometallic aromatic compound represented by the following formula (1) or a polymer blend containing the polymer; and
(b) an organic solvent; an anti-reflective hard mask composition comprising:
[Formula 1]

In the above formula, R1, R2, and R3 are each composed of C1~C10 alkyl, C1~C10 alkoxy, C2~C10 alkenyl, and C6~C20 aryl group. one selected from the group,
R1, R2, and R3 may each be the same or different from each other,
M is Ge or Sn,
R4 and R5 are any one selected from hydrogen (H), C1~C10 alkyl, C2~C10 alkenyl, and C6~C40 aryl group,
R4 and R5 may be the same or different from each other,
A is an aryl group of C6 to C40, and may be substituted or unsubstituted with a halogen group, nitro group, amino group, formyl group, carboxyl group, or hydroxyl group, and may or may not include an ether bond, a ketone bond, or an ester bond. There is,
n = 2 or more,
The weight average molecular weight (Mw) of the polymer is 1,000 to 30,000. delete According to paragraph 1,
Wherein R1, R2, and R3 are each selected from the group consisting of a C1-C10 alkyl group and a C6-C20 aryl group. According to paragraph 1,
Wherein R4 and R5 are each selected from the group consisting of hydrogen, phenyl, bismethylbenzene, biphenyl, and phenoxyphenyl. According to paragraph 1,
Wherein A is naphthalene, pyrene, or hydroxyphenylfluorene. According to any one of claims 1, 3 to 5,
The hard mask composition is an anti-reflective hard mask composition further comprising a crosslinker and an acid catalyst component. According to clause 6,
The hard mask composition is,
(a) a polymer consisting of an organometallic aromatic compound represented by the above formula (1)
or 1 to 30% by weight of a polymer in the form of a polymer blend containing the same or a polymer blend containing the same;
(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) An anti-reflective hard mask composition containing a remaining amount of the organic solvent. According to clause 6,
The crosslinking agent is an antireflective hardmask composition selected from the group consisting of melamine resin, amino resin, glycoluryl compound, and bisepoxy compound. According to clause 6,
The acid catalyst is p-toluenesulfonic acid monohydrate, pyridinium p-toluene sulfonate, 2,4,4,6-tetrabromocyclohexadienone, and benzoate. An antireflective hardmask composition selected from the group consisting of phosphorus tosylate, 2-nitrobenzyl tosylate, and alkyl esters of organic sulfonic acids.