KR100367399B1 - Organic diffuse reflection prevention polymer and its manufacturing method - Google Patents

Abstract

The present invention prevents the reflection of the underlying layer in the ultrafine pattern formation process using 248 nm krF and 193 nm ArF lithography photoresist during the semiconductor device manufacturing process and removes the sine wave in the thickness change of ArF light and photoresist itself. The present invention relates to an organic anti-reflective polymer and a method for synthesizing the same, and the present invention also relates to an anti-reflective composition containing such an organic anti-reflective polymer, an anti-reflective coating using the same, and a method for producing the same. When the polymer according to the present invention is used as a reflective ring film in the ultrafine pattern forming process of the semiconductor manufacturing process, the stable ultrafine pattern of 64M, 256M, IG, 4G and l6G DRAMs is removed by eliminating the CD variation caused by the lower layer. It can form, and can increase the yield of a product.

Description

Organic diffuse reflection prevention polymer and manufacturing method thereof

The present invention prevents the reflection of the underlying layer in the ultrafine pattern formation process using the photoresist for 248 nm KrF and 193 nm ArF lithography during the semiconductor device manufacturing process and removes the sine wave in the thickness change of ArF light and photoresist itself. The present invention relates to an organic anti-reflective polymer that can be used for forming ultrafine patterns of 64M, 256M, IG, and 4G DRAM as an antireflection organic material, and a method of manufacturing the same. The present invention also relates to an antireflective composition containing such an organic antireflective polymer, an antireflection film using the same, and a method of manufacturing the same.

In the ultra-fine pattern formation process of the semiconductor manufacturing process, the reflective wave not only reflects the standing wave due to the optical properties of the lower layer on the wafer and the thickness of the photoresist layer, but also the CD (critical dimension) by diffracted and reflected light from the lower layer. ) Inevitably occurs. Therefore, the introduction of an organic material that absorbs light well in the wavelength range of light used as an exposure source has been proposed to introduce a film layer that can prevent reflection in the lower film layer, which is called an anti-reflection film.

The antireflection film is classified into an inorganic antireflection film and an organic antireflection film according to the type of material used largely, or is classified into an absorption antireflection film and an interferometer antireflection film according to a mechanism. In the micropattern forming process using an I-line having a wavelength of 365 nm, an inorganic antireflection film is mainly used. TiN and amorphous carbon (Amorphous C) are used as absorbers, and SiON is mainly used as an interferometer.

In the ultrafine pattern formation process using KrF light, SiON has been mainly used as an inorganic type, and in recent years, efforts to use organic compounds in antireflection films have been continued. In light of the trends to date, most of the existing organic anti-reflective coatings for KrF must satisfy the following basic conditions.

First, there should be no phenomenon that the photoresist is dissolved and peeled off by the solvent when the process is applied. To this end, the molded film must be designed to achieve a crosslinked structure, and chemicals should not be generated as a by-product.

Second, there should be no entry of chemicals such as acids or amines from the antireflection film. If the acid is migrated from the anti-reflection film, undercutting occurs at the bottom of the pattern, and bases such as amines tend to cause footing phenomenon.

Third, the anti-reflection film should have a relatively high etching rate compared to the upper photoresist so that a smooth etching process can be performed using the photoresist as a mask during etching.

Fourth, therefore, the antireflection film should be able to serve as a sufficient antireflection film with a thickness as thin as possible.

On the other hand, in the ultrafine pattern formation process using ArF light, such an anti-reflection film has not been developed yet. In addition, in the case of the inorganic antireflection film, a material for controlling the interference at 193 nm, which is a light source, has not been published yet, and the recent trend is to study the use of organic compounds in the antireflection film.

Therefore, in all photoresist films, it is necessary to use an organic anti-reflective material having high absorption at a specific wavelength in order to prevent sine wave and reflection generated during exposure and to remove the influence of back diffraction and reflected light from the lower layer. It is an urgent task.

The technical problem to be achieved by the present invention is to provide a novel compound that can be used as an anti-reflection film in the ultra-fine pattern formation process using 193 nm ArF and 248 nm Krk light during the semiconductor manufacturing process.

Still another object of the present invention is to provide a method for preparing a compound which can prevent diffuse reflection.

Still another object of the present invention is to provide an anti-reflective composition containing the compound for preventing anti-reflection and a manufacturing method thereof.

Another object of the present invention is to provide an anti-reflection film formed using such an anti-reflective composition and a method of forming the same.

In order to achieve the above technical problem, the present invention has a structure of Formula 1 below, and has a poly ((methyl acrylate)-(hydroxy ethyl acrylate)-(styrene)] for an organic antireflection film having an average molecular weight of 500-100000. (Poly [(alkyl acrylate)-(hydroxy alkyl acryrene)]) polymer is provided.

[Formula 1]

Where

R ₁ represents hydrogen, C ₁ -C ₄ alkyl, hydroxy, or hydroxymethyl group,

R ₂ represents hydrogen, a C ₁ to C ₄ alkyl, hydroxy, or hydroxymethyl group,

R ₃ represents hydrogen, C ₁ -C ₄ alkyl, hydroxy, C ₁ -C ₃ hydroxyalkyl, methoxy, formylethyl, or formylethoxy group,

1, m, and n show the molar ratio of 1: m: n is 0.1-0.9: 0.1-0.9: 0.1-0.9.

As described above, the average molecular weight (Mn) of the polymer of Formula 1 according to the present invention is preferably 500 to 100,000. When the average molecular weight is less than 500, the molded film cannot form a crosslinked structure sufficiently, and thus the antireflection film formed by the polymer may be peeled off by the solvent, and when it is 100,000 or more, the viscosity of the polymer becomes too high, It is not suitable for advancing the application process of the antireflection film. However, the molecular weight of such an antireflection film polymer is a common one that will be apparent to those skilled in the art.

The polymer of Chemical Formula 1 according to the present invention contains a phenyl group having a high absorbance at l93 nm wavelength so that absorption occurs at l93 nm and 248 nm wavelengths, and is designed to absorb at 248 nm by introducing a chromophore.

The polymer of Chemical Formula 1 according to the present invention is polymerized by reacting methyl acrylate monomer (I), hydroxyethyl acrylate monomer (II) and styrene monomer (III) with an initiator in a solvent as shown in Scheme 1 below. It can manufacture.

Scheme 1

Where

R ₁ represents hydrogen, C ₁ -C ₄ alkyl, hydroxy, or hydroxymethyl group,

R ₂ represents hydrogen, a C _{1 to} C ₄ alkyl, hydroxy, or hydroxymethyl group,

R ₃ represents hydrogen, C ₁ -C ₄ alkyl, hydroxy, C ₁ -C ₃ hydroxyalkyl, methoxy, formylethyl, or formylethoxy group.

At this time, the molar ratio of each monomer in Scheme 1 may be composed of a molar ratio of 0.1 to 0.9: 0.1 to 0.9: 0.1 to 0.9. This is to prevent some of the reactants from remaining unreacted when the polymer of Chemical Formula 1 is prepared by the reaction of Scheme 1, and the reaction of Scheme 1 is a simple polymerization of ethylene having a high yield. By adding each reactant in accordance with the molar ratio of the monomers included, it is possible to prevent some reactants from remaining unreacted.

Initiators that can be used to prepare the polymer of Formula 1 according to the present invention may be used a general radical initiator, preferably 2,2-azobisisobutyronitrile (AIBN), acetyl peroxide, lauryl per Oxide, t-butylperoxide may be selected from the group consisting of.

As a solvent used in the method for preparing a polymer of Chemical Formula 1 according to the present invention, a general organic solvent may be used, and preferably selected from the group consisting of tetrahydroxyfuran, toluene, benzene, methyl ethyl ketone or dioxane. Can be used

In the method for preparing a polymer of Chemical Formula 1 according to the present invention, the reaction temperature is preferably performed at 50 to 80 ° C. The reaction temperature is a typical reaction temperature at which a simple polymerization reaction can occur. If the reaction proceeds at a temperature lower than the above temperature, the polymerization reaction does not occur completely, and when it is high, a co-reaction may occur.

The present invention also includes the polymer of Formula 1 alone or as an anthracene derivative, a fluorenone derivative, a fluorene derivative, a xanthone, quinizarine and fluorescein as described in Table 1 and Table 1 and It is characterized by providing an anti-reflective coating composition, characterized in that it consists of one or two or more compounds selected from the group consisting of.

In Table la below, R ₅ , R ₆ , or R ₇ each independently represent hydrogen, C ₁ -C ₅ substituted or unsubstituted straight or branched chain alkyl, cycloalkyl, alkoxyalkyl or cycloalkoxyalkyl, p is Represents an integer.

In Table 1b below, R ₈ to R ₁₅ each independently represent hydrogen, hydroxy, C ₁ -C ₈ substituted or unsubstituted straight or branched chain alkyl, cycloalkyl, alkoxyalkyl or cycloalkoxyalkyl, R ₁₆ and R ₁₇ each independently represents an alkyl group.

Table la

TABLE 1b

The method for preparing an antireflection film composition according to the present invention is prepared by dissolving the polymer of Chemical Formula 1 in an organic solvent and then adding 0.1 to 40% by weight of the compound selected from Table la and Table 1b. The compound is intended to further increase the absorbance of the light source. When the amount of the added substance is less than 0.1% by weight, the absorbance of the antireflective film formed by the composition cannot be sufficiently increased. The amount of the polymer of Formula 1 included in the composition is reduced, so that the antireflection film formed by the composition cannot sufficiently form a crosslinked structure.

In this case, a conventional organic solvent may be used as the organic solvent, and preferably, ethyl 3-ethoxypropionate, buckwheat 3-methoxy propionate, cyclohexanone, and propylene glycol methyl ether acetate are used. You can use the selected one from the group.

In addition, the amount of solvent used in the production of the antireflection film composition of the present invention is preferably used 200 to 5000% by weight per weight of the polymer of the formula (1). Such solvent amount is a solvent amount usually used in preparing an antireflection film composition, and by using such a solvent amount, the antireflection film polymer can be completely dissolved, and an appropriate amount of solvent for forming the antireflection film using the composition. do.

The present invention is the polymer of formula (I) alone or in the group consisting of the polymer of formula (I) and the anthracene derivatives, fluorenone derivatives, fluorene derivatives, xanthones, quinizarine and fluorescein described in Table la and Table 1b. An anti-reflection film made of a composition containing one or more selected compounds is provided.

The antireflection film according to the present invention is a polymer of formula (I) alone, or the polymer of formula (I) and the anthracene derivatives, fluorenone derivatives, fluorene derivatives, xanthones, quinizarine and fluoresce described in Table la and Table 1b. After filtering the composition containing one or two or more compounds selected from the group consisting of phosphorus, it can be prepared by cross-linking the antireflection film resin by coating on a wafer and hard-baking for 10 to 1000 seconds at 100 ~ 300 ℃. By carrying out the hard bake under such conditions, the antireflection film resin can be crosslinked to harden the molded film, and when the process temperature is higher than 300 ° C. or the process time is greater than 1000 seconds, the molded film may be destroyed. Can be.

The crosslinking reaction in the antireflection film according to the present invention takes place by the same mechanism as in Scheme 2 below.

Scheme 2

Where

R ₁ represents hydrogen, C ₁ -C ₄ alkyl, hydroxy, or hydroxymethyl group,

R ₂ represents hydrogen, a C ₁ to C ₄ alkyl, hydroxy, or hydroxymethyl group,

R ₃ represents hydrogen, C ₁ -C ₄ alkyl, hydroxy, C ₁ -C ₃ hydroxyalkyl, methoxy, formylethyl, or formylethoxy group,

1, m, and n show the molar ratio of 1: m: n is 0.1-0.9: 0.1-0.9: 0.1-0.9.

When the antireflection film composition according to the present invention is coated on a wafer and then hardbaked at a high temperature, an ester group and an aryl alcohol group in the polymer of Chemical Formula 1 react to produce a transesterification reaction to form methanol as shown in Scheme 2 above. The resins form a crosslinked structure with each other.

This crosslinked structure makes it possible to form optically stable exposure conditions as the organic antireflection film when the photosensitive film is applied. By-product methanol is completely evaporated during hard baking, so intermixing with the photosensitive film does not occur at all, resulting in structurally excellent film characteristics.

The polymer of Chemical Formula 1 according to the present invention was found to exhibit excellent performance as an organic anti-reflective coating of the ultra-fine pattern forming process using 248nm KrF and 193 ArF laser as a light source, E-beam, EUV as an exposure light source in addition to ArF light (extremely ultraviolet), an ion beam, etc., it was confirmed that the excellent anti-reflective effect.

Hereinafter, the present invention will be described in more detail. In addition, the present embodiment is not intended to limit the scope of the present invention but is presented by way of example only.

Example 1 Synthesis of Poly (methylmethacrylate-hydroxyethylmethacrylate-styrene) Copolymer

30 g (0.3 mole) of methyl methacrylate monomer, 39 g (0.3 mole) of hydroxy ethyl methacrylate and 41.7 g (0.4 mole) of styrene were added to a 500 ml round bottom flask, and 300 g of tetrahydrofuran (THF) prepared in advance was stirred. After the mixture is completely mixed, 0.1 g-3 g of 2.2'-azobisisobutyroacrylate (AIBN) is added thereto, and the mixture is reacted at 60 ° C. to 75 ° C. for 5-20 hours under a nitrogen atmosphere. After completion of the reaction, the solution is precipitated in ethyl ether or normal nucleic acid solvent, filtered and dried to obtain a poly (methyl methacrylate-hydroxy ethyl methacrylate-styrene) copolymer which is a polymer according to the present invention. Yield was 70-76%.

Example 2 Synthesis of Poly (methylmethacrylate-hydroxyethylacrylate-α-methylstyrene) Copolymer

30 g (0.3 mole) of methyl methacrylate monomer, 40.6 g (0.35 mole) of hydroxy ethyl acrylate and 41.4 g (0,35 mole) of α-methyl styrene were put into a 500 ml round bottom flask and prepared with tetrahydrofuran. (THF) When 300g is added and thoroughly mixed, 0.1g-3g of 2.2'-azobisisobutyroacrylate (AIBN) is added thereto, followed by reaction for 5-20 hours at a temperature of 50 ° C to 65 ° C under a nitrogen atmosphere. After completion of the reaction, the solution is precipitated in ethyl ether or normal nucleic acid solvent, filtered and dried to obtain a poly (methylmethacrylate-hydroxy ethylacrylate-a-methylstyrene) copolymer which is a polymer according to the present invention. The yield was 80-87%.

Example 3 Synthesis of Poly (methylmethacrylate-hydroxyethylmethacrylate-vinylanisol) copolymer

30 g (0.3 mole) of methyl methacrylate monomer, 39 g (0.3 mole) of hydroxy ethyl methacrylate and 47 g (0.35 mole) of 4-vinylanizol were put into a 500 ml round bottom flask and prepared with tetrahydrofuran (THF). ) 300g is added, and when thoroughly mixed, 0.1g-3g of 2.2'-azobisisobutyroacrylate (AIBN) is added thereto, and reacted at a temperature of 60 ° C. to 80 ° C. for 5-20 hours under a nitrogen atmosphere. After completion of the reaction, the solution is precipitated in ethyl ether or normal nucleic acid solvent, filtered and dried to obtain a poly (methyl methacrylate-hydroxy ethyl methacrylate-vinyl anisole) copolymer according to the present invention. The yield was 75 to 80%.

Example 4 Synthesis of Poly (methylmethacrylate-hydroxy ethylacrylate-vinylbenzoate) copolymer

30 g (0.3 mole) of methyl methacrylate monomer, 40.6 g (0.35 mole) of hydroxy ethyl acrylate and 44.4 g (0.3 mole) of vinyl benzoate were placed into a 500 ml round bottom flask and prepared with tetrahydrofuran (THF). When 300g is added and thoroughly mixed, 0.1g-3g of 2.2'-azobisisobutyroacrylate (AIBN) is added thereto, followed by reaction for 5-20 hours at a temperature of 60 ° C to 75 ° C under a nitrogen atmosphere. After completion of the reaction, the solution is precipitated in ethyl ether or normal nucleic acid solvent, filtered and dried to obtain a poly (methylmethacrylate-hydroxy ethylacrylate-vinylbenzoate) copolymer which is a polymer according to the present invention. Yield was 65-70%.

Example 5 Preparation of Anti-Reflection Film

50 mg of each polymer according to the present invention prepared in Examples 1 to 4 was dissolved in about 100 g of propylene glycol methyl ether acetate (PGMEA), and then 0.1 to 30% by weight of the compounds of Table la and Table 1b were completely dissolved. Then, the filtered solution is applied to a wafer and hardbaked at 100 to 300 ° C. for 10 to 1000 seconds. Thereafter, a photosensitive film is applied to perform a fine pattern forming step.

As described above, when the polymer of Chemical Formula 1 according to the present invention is used as an anti-reflection film in an ultra-fine pattern forming process of a semiconductor manufacturing process, 64M, 256M, IG, 4G, l6G by removing the CD variation caused by the lower layer It is possible to form a stable ultra-fine pattern of DRAM can increase the yield of the product.

Claims (12)

Poly [(methylacrylate)-(hydroxy ethyl acrylate)-(styrene)] (Poly [(alkyl acryate)-(hydroxy) for an organic antireflective coating film having a structure of Formula 1 below and having an average molecular weight of 500-100000. alkyl acrylate)-(styrene)]) polymer. (Formula 1) Where R ₁ represents hydrogen, C ₁ -C ₄ alkyl, hydroxy, or hydroxymethyl group, R ₂ represents hydrogen, a C _{1 to} C ₄ alkyl, hydroxy, or hydroxymethyl group, R ₃ represents hydrogen, C ₁ -C ₄ alkyl, hydroxy, C ₁ -C ₃ hydroxyalkyl, methoxy, formylethyl, or formylethoxy group, 1, m, and n show the molar ratio of 1: m: n is 0.1-0.9: 0.1-0.9: 0.1-0.9. The compound of claim 1, wherein R ₁ represents a methyl group, R ₂ represents hydrogen or a methyl group, R ₃ represents hydrogen or a methyl group, and 1, m and n represent a molar ratio of 0.1 to 0.9: 0.1 to 0.9: 0.1 to 0.9 A polymer characterized by the above-mentioned. As shown in the following Scheme 1, methyl acrylate monomer (I), hydroxy ethyl acrylate monomer (II) and styrene monomer (III) together with a radical initiator (tetrahydrofuran, toluene, benzene, methyl A process for preparing the polymer of claim 1 by reacting in a solvent selected from the group consisting of ethyl ketone or dioxane. (Scheme 1) Where R ₁ represents hydrogen, C ₁ -C ₄ alkyl, hydroxy, or hydroxymethyl group, R ₂ represents hydrogen, a C ₁ to C ₄ alkyl, hydroxy, or hydroxymethyl group, R ₃ represents hydrogen, C ₁ -C ₄ alkyl, hydroxy, C ₁ -C ₃ hydroxyalkyl, methoxy, formylethyl, or formylethoxy group. The method of claim 3, wherein the molar ratio of each monomer is composed of a molar ratio of 0.1 to 0.9: 0.1 to 0.9: 0.1 to 0,9. The method of claim 3, wherein the radical initiator is selected from the group consisting of 2,2-azobisisobutyronitrile (AIBN), acetyl peroxide, lauryl peroxide, t-butyl peroxide Way. The method of claim 3, wherein the polymerization reaction is carried out at a temperature range of 50 ~ 80 ℃. The polymer of claim 1, and anthracene, 9-anthracenemethanol, 9-anthracenecarbonitrile, 9-anthracenecarboxylic acid, ditranol, 1,2,10-anthracentriol, anthraclavonic acid, 9-anthralaldehyde Oxime, 9-anthralaldehyde, 2-amino-7-methyl-5-oxo-5H- [1] benzopyrano [2,3-b] pyridine-3-carbonitrile, 1-aminoanthraquinone, anthraquinone 2-carboxylic acid, 1,5-dihydroxy, anthraquinone, anthrone, 9-anthryltrifluoromethyl ketone, 9-alkyl anthracene derivative of formula (2), 9-carboxy anthracene of formula (3) Derivatives, 1-carboxyl anthracene derivative of formula (4), fluorenone derivative of formula (5), fluorenone derivative of formula (6), fluorenone derivative of formula (7), fluorenone derivative of formula (8), fluorene, 9- Fluorene acetic acid, 2-fluorene carboxaldehyde, 2-fluorene carboxylic acid, 1-fluorene car One or two or more compounds selected from the group consisting of leric acid, 4-fluorene carboxylic acid, 9-fluorene carboxylic acid, 9-fluorenemethanol, fluorenol, xanthone, quinizarine and fluorescein An antireflection film composition, characterized in that it contains. [Formula 2] [Formula 3] [Formula 4] [Formula 5] [Formula 6] [Formula 7] [Formula 8] In the above formula R ₅ , R ₆ , or R ₇ each independently represent hydrogen, C ₁ to C ₅ substituted or unsubstituted straight or branched chain alkyl, cycloalkyl, alkoxyalkyl or cycloalkoxyalkyl, R ₈ to R ₁₅ each independently represent hydrogen, hydroxy, C ₁ -C ₅ substituted or unsubstituted linear or branched alkyl, cycloalkyl, alkoxyalkyl or cycloalkoxyalkyl, R ₁₆ and R ₁₇ each independently represent an alkyl group, p represents an integer. The polymer of claim 1, wherein one or two selected from the group consisting of 200-5000% by weight of ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, cyclohexanone, propylene glycol, methyl ether acetate After dissolving in the above organic solvent, and then anthracene, 9-anthracenemethanol, 9-anthracenecarbonitrile, 9-anthracenecarboxylic acid, ditranol, 1,2,10-anthracentriol, anthralflavic acid, 9-anthral Dehydrate oxime, 9-anthralaldehyde, 2-amino-7-methyl-5-oxo-5H- [1] benzopyrano [2,3-b] pyridine-3-carbonitrile, 1-aminoanthraquinone, anthra Quinone-2-carboxylic acid, 1,5-dihydroxy, anthraquinone, anthrone, 9-anthryltrifluoromethyl ketone, 9-alkyl anthracene derivative of formula (2), 9-carboxyl of formula (3) Anthracene derivative, 1-carboxyanthracene derivative of Formula 4, Orenone derivative, fluorenone derivative of formula (6), fluorenone derivative of formula (7), fluorenone derivative of formula (8), fluorene, 9-fluorene acetic acid, 2-fluorene carboxaldehyde, 2-fluorene carbide Acid, 1-fluorene carboxylic acid, 4-fluorene carboxylic acid, 9-fluorene carboxylic acid, 9-fluorenemethanol, fluorenol, xanthone, quinizaline and fluorescein Method for producing an anti-reflection film composition characterized in that the addition of one or two or more compounds selected. (Formula 2) (Formula 3) (Formula 4) (Formula 5) (Formula 6) (Formula 7) (Formula 8) In the above formula R ₅ , R ₆ , or R ₇ each independently represent hydrogen, C ₁ to C ₅ substituted or unsubstituted straight or branched chain alkyl, cycloalkyl, alkoxyalkyl or cycloalkoxyalkyl, R ₈ to R ₁₅ each independently represent hydrogen, hydroxy, C ₁ -C ₅ substituted or unsubstituted linear or branched alkyl, cycloalkyl, alkoxyalkyl or cycloalkoxyalkyl, R ₁₆ and R ₁₇ each independently represent an alkyl group, p represents an integer. 10. The process according to claim 9, wherein the compound added after dissolving the polymer of claim 1 in a solvent is used at a ratio of 0.1-40% by weight based on the total composition. An anti-reflection film composition comprising the polymer of claim 1. Applying the antireflective film composition of claim 12 to a wafer; Hard-baking the wafer at 100-300 ° C. for 10-1000 seconds. Filtering the antireflective coating composition of claim 8; Applying the composition to a wafer and hard-baking at 100-300 ° C. for 10-1000 seconds.