KR20020032492A - Anti-reflective coating polymers and preparation thereof - Google Patents

Abstract

PURPOSE: Provided are an organic compound which completely satisfies conditions requisite for antireflection film and can be used in process for forming submicron pattern using 193 nm ArF light, and a method for preparing the same. CONSTITUTION: The organic compound is represented by formula 1. In the formula 1, Ra, Rb, Rc and Rd are hydrogen or methyl group individually, R1 to R4 represent hydrogen, or substituted or unsubstituted linear or branched alkyl or alkoxyalkyl of C1-C5, w, x, y and z represent molar fraction, which are 0.1-0.9, and l, m, n and p are an integer of 1-3 individually. The organic compound is prepared by polymerizing monomer having structure of formula 2, hydroxyalkyl acrylate based monomer, alkyl acrylate based monomer and glycidyl acrylate based monomer in the presence of initiator in solvent. In the formula 2, Ra, R1-R4 and p are the same as the formula 1.

Description

Anti-reflective coating polymer and its manufacturing method {ANTI-REFLECTIVE COATING POLYMERS AND PREPARATION THEREOF}

The present invention relates to a polymer that can be used as an antireflection film in a semiconductor device manufacturing process and a method of manufacturing the same, and more particularly, to using a lithography photoresist using a 193 nm ArF laser during a semiconductor device manufacturing process. The present invention relates to an antireflection organic material that can prevent reflection of a lower layer in a pattern forming process and remove standing waves due to changes in thickness of ArF light and photoresist itself, and can be used when forming ultrafine patterns of 1G and 4G DRAM. An organic anti-reflective polymer and a method for producing 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 CD (critical dimension) by standing wave, reflective notching and diffracted light from the lower film and reflected light due to the variation of optical properties and photoresist thickness of the lower film layer on the wafer ) Inevitably occurs. Therefore, there has been a proposal to introduce an organic material film layer that absorbs light well in the wavelength range of light used as an exposure source so as to prevent reflection in the lower layer, which is an antireflection film.

The antireflection film is classified into an inorganic antireflection film and an organic antireflection film according to the type of material used, or is divided into an absorption antireflection film and an interferometer antireflection film according to a mechanism. Inorganic anti-reflective coatings have been mainly used in the micropattern forming process using I-line of 365nm wavelength, and TiN and amorphous carbon (Amorphous C) are mainly used as anti-reflective coatings for absorption, SiON has been used.

In the ultrafine pattern formation process using KrF light, SiON has been mainly used as an inorganic antireflection film, but efforts have recently been made to use an organic compound in an antireflection film. Even in the formation of ultrafine patterns using ArF light, an organic antireflection film has emerged as a viable countermeasure against an antireflection film. In light of the trends to date, most of the organic anti-reflective coatings must satisfy the following basic conditions.

(1) During the application of the process, the photoresist should not be dissolved and peeled off by the solvent. To this end, the molded film must be designed to achieve a crosslinked structure, and chemicals should not be generated as a by-product.

(2) There should be no entry of chemicals such as acids or amines from the antireflection film. If the acid is migrated from the antireflection film, undercutting occurs at the bottom of the pattern, and bases such as amines tend to cause footing as the base migrates.

(3) The anti-reflection film should have a relatively high etching rate compared to the upper photoresist film in order to perform a smooth etching process using the photoresist film as a mask during etching.

(4) The antireflection film should therefore be able to serve as a sufficient antireflection film with a thickness as thin as possible.

Meanwhile, a satisfactory anti-reflection film has not been developed in an ultrafine pattern forming process using ArF light. In the case of the inorganic antireflection film, a material for controlling the interference phenomenon at 193 nm, which is a light source, has not been announced yet, and efforts to use an organic antireflection film have been continued in recent years.

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

Accordingly, an object of the present invention is to satisfy all of the conditions to be provided as the anti-reflective coating, and a novel organic compound that can be used as an anti-reflective coating in an ultra-fine pattern forming process using 193 nm ArF light during a semiconductor device manufacturing process and a method of manufacturing the same. To provide.

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.

Still another object of the present invention is to provide an antireflection film formed using such an antireflection composition and a method of forming the same.

In all photoresist films, the use of anti-reflective materials to eliminate light interference due to standing diffraction and reflection from the underlying film and standing wave and reflection notching generated during exposure is essential, and the anti-reflective coating material must have high absorption to a specific wavelength. It can be used as an antireflection film. In the present invention, it is designed to contain a phenyl group having a high absorbance in the polymer so that absorption occurs at a wavelength of 193nm, the resin so that the crosslinking reaction can occur during the hard bake after coating to give the moldability, airtightness, solvent resistance, etc. of the organic antireflection film A mechanism for crosslinking by the ring-opening reaction of the epoxy structure within was introduced. In particular, the antireflective coating resin of the present invention has excellent solubility in all solvents of the hydrocarbon system and has solvent resistance which does not dissolve in any solvent during hard baking. Therefore, no problem occurs during the application of the photoresist film, and undercutting and footing do not occur during pattern formation, and in particular, since the bonds of the crosslinked chains are made of CO bonds, the etching rate is superior to that of the ArF photoresist film during etching. Etch selectivity is significantly improved.

The basic formula of the resin used as the organic antireflection film of the present invention is as shown in the following formula (1).

In the above formula,

R _a , R _b , R _c and R _d each represent a hydrogen or methyl group,

R ₁ to R ₄ are each hydrogen or substituted or unsubstituted linear or branched alkyl having 1 to 5 carbon atoms or alkoxy alkyl, and R ₅ is —H, —OH, —COCH ₃ or substituted or unsubstituted 1 to 4 carbon atoms; Ring linear or branched alkyl, cycloalkyl or alkoxyalkyl, cycloalkoxyalkyl, w, x, y, z each represent a mole fraction of 0.1 to 0.9, and l, m, n, p each represent an integer of 1 to 3. .

The polymer of Chemical Formula 1 according to the present invention is a 4- (4-hydroxyphenyl) pyruvic alcohol acrylate monomer, a hydroxy alkyl acrylate monomer, an alkyl acrylate monomer, and glyci It may be prepared by polymerization in a solvent with a diacrylate acrylate monomer initiator, wherein each monomer has a ratio of 0.1 to 0.9 mole fraction.

In Chemical Formula 2,

R _a is hydrogen or a methyl group, R ₁ to R ₄ are each hydrogen or substituted or unsubstituted straight or branched chain alkyl having 1 to 5 carbon atoms or alkoxy alkyl, R ₅ is -H, -OH, -COCH ₃ or Substituted or unsubstituted linear or branched alkyl of 1 to 4 carbon atoms, cycloalkyl or alkoxyalkyl, cycloalkoxyalkyl, l, p represent an integer of 1 to 3, respectively.

As an initiator used to prepare the polymer of Chemical Formula 1 according to the present invention, a general radical initiator may be used, and preferably 2,2-azobisisobutyronitrile (AIBN), acetyl peroxide, lauryl perfer Oxide, t-butylperoxide may be selected from the group consisting of, and as a solvent in the polymer reaction may be used a general organic solvent, preferably tetrahydrofuran, toluene, benzene, methyl ethyl ketone or dioxane You can use the selected one from the group you have made.

In the method for producing a polymer of Chemical Formula 1 according to the present invention, the temperature of the polymerization reaction is preferably set to 50 to 80 ° C.

The present invention also provides a method for preparing a composition for anti-reflection coating by dissolving the polymer of Formula 1 in an organic solvent, wherein the organic solvent may be used a conventional organic solvent, preferably ethyl 3-ethoxy Propionate, methyl 3-methoxy propionate, cyclohexanone, propylene glycol methyl ether acetate and the like can be used. At this time, the amount of the solvent is preferably 200 to 5000% by weight.

The present invention also provides a method for forming an anti-reflection film comprising the step of applying a hard-baked solution of the compound of Formula 1 in an organic solvent to a wafer. The organic solvent used at this time may be used a conventional organic solvent, in particular those selected from the group consisting of ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, cyclohexanone, propylene glycol methyl ether acetate It is preferable to use, and the amount of the organic solvent is preferably 200 to 5000% by weight of the antireflection film resin used.

In addition, the hard bake is preferably performed at a temperature of 100 to 300 ° C. for 10 to 1000 seconds, and is formed by crosslinking the antireflection film resin through the hard bake.

In addition, the polymer of Formula 1 prepared by the above method was found to exhibit excellent performance as an organic anti-reflection film of the ultra-fine pattern forming process using 193nm ArF and 157nmF ₂ laser.

The present invention also provides a composition for an anti-reflection film comprising any one of the compounds having the structure of Formula 1, and provides a semiconductor device comprising an anti-reflection film prepared using the composition for anti-reflection film. do.

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

Example 1 Synthesis of 4- (4-hydroxyphenoxy) acetoxy isopropanol methacrylate monomer

0.35 mole of 4-hydroxyphenylacetic acid was added to 100 g of tetrahydrofuran (THF), completely dissolved, and mixed. Then, 100 g of THF dissolved in 0.35 mole of p-toluene sulfonic acid was added, followed by glycidyl methacrylate in a nitrogen atmosphere. 0.3 mol of 4-methoxyphenol) was slowly added thereto and reacted for 24 hours. Checking the reaction TLC as in the reaction when the reaction was complete after washing with deionized water and extract the reaction product of the organic solvent layer as MgSO ₄ to remove the water in the organic solvent, and then distilled under reduced pressure to obtain a monomer of formula (3). At this time, the yield was 85 to 90%.

Example 2 Synthesis of 4- (4-hydroxyphenyl) pyruvicisopropanol methacrylate monomer

0.35 mole of 4-hydroxyphenylpyruvic acid was added to 100 g of tetrahydrofuran (THF), completely dissolved and mixed, 100 g of THF dissolved in 0.35 mole of p-toluene sulfonic acid was added, followed by glycidyl methacrylate (polymerization) in a nitrogen atmosphere. 0.3 mol) of 4-methoxyphenol as an inhibitor was slowly added thereto and reacted for 10 hours or longer. To check the reaction by TLC as in the reaction, and the reaction was completed, washing with deionized water and removal of water in the organic solvent extract the reaction product of the organic solvent layer as MgSO ₄ and then distilled under reduced pressure to obtain a monomer of the formula (4). At this time, the yield was 80 to 85%.

Example 3 Synthesis of Vinyl 4- (2-butanone) benzoate Monomer

0.35 mole of 4- (4-hydroxyphenyl) -2-butanone was added to 0.35 mole of triethylamine, and the mixture was completely dissolved. 0.33 mole of acryloyl chloride was added and reacted slowly under a nitrogen atmosphere. At this time, since heat is generated, the reaction is cooled and the reaction is continued for 24 hours or more. Reaction during when checking the reaction by TLC and the reaction was complete was neutralized with a sulfuric acid aqueous solution of 1N, then washed with deionized water to extract the reaction product of an organic solvent layer and removing the water in the organic solvent as MgSO ₄ monomer of the general formula (V) Got. Yield was 90 to 95%.

Example 4 Synthesis of Vinyl 4- (3-methoxy) benzoate Acetone Monomer

0.35 mol of 4-hydroxy-3-methoxyphenylacetone was added to 0.35 mol of triethylamine, and the mixture was completely dissolved. After mixing, 0.33 mol of acryloyl chloride was added and reacted slowly in a nitrogen atmosphere. At this time, since heat is generated, the reaction is cooled and the reaction is continued for 24 hours or more. During the reaction, the reaction rate was checked by TLC, and when the reaction was completed, the reaction mixture was neutralized with 1N aqueous sulfuric acid solution, washed with deionized water, the reaction product of the organic solvent layer was extracted, and water in the organic solvent was removed using MgSO ₄ to remove the monomer of Chemical Formula 6 Got. Yield was 90 to 95%.

(Example 5)

Synthesis of Poly [4- (4-hydroxyphenoxy) acetoxyisopropanol methacrylate-hydroxyethyl methacrylate-methylmethacrylate-glycidyl methacrylate] quapolymer

0.3 mol of 4- (4-hydroxyphenoxy) acetoxyisopropanol methacrylate, 0.25 mol of hydroxyethyl acrylate, 0.1 mol of methyl methacrylate, and 0.3 mol of glycidyl methacrylate were added to a 500 ml round bottom flask and stirred. While preparing 300 g of THF prepared in advance and thoroughly mixed, 0.1 to 3.0 g of 2,2'-azobisisobutylonitrile (ABIN) was added thereto, and the reaction was carried out at a temperature of 60 ° C. to 75 ° C. for 5 to 20 hours under a nitrogen atmosphere. After completion of the reaction, the solution was precipitated in ethyl ether or normal nucleic acid solution, filtered and dried to obtain poly [4- (4-hydroxyphenoxy) acetoxyisopropanol methacrylate-hydroxyethyl as shown in the following formula (7). Methacrylate-methyl methacrylate-glycidyl methacrylate] resin was obtained. The yield was then 65-70%.

(Example 6)

Synthesis of Poly [4- (4-hydroxyphenyl) pyruvicisopropanol methacrylate-hydroxyethyl methacrylate-methylmethacrylate-glycidyl methacrylate] quapolymer

0.3 mol of 4- (4-hydroxyphenyl) pyruvic isopropanol methacrylate, 0.2 mol of hydroxyethyl methacrylate, 0.15 mol of methyl methacrylate, and 0.3 mol of glycidyl methacrylate were added to a 500 ml round bottom flask and stirred. While preparing 300 g of THF prepared in advance and thoroughly mixed, 0.1 to 3.0 g of 2,2'-azobisisobutylonitrile (ABIN) was added thereto, and the reaction was carried out at a temperature of 60 ° C. to 75 ° C. for 5 to 20 hours under a nitrogen atmosphere. After completion of the reaction, the solution was precipitated in ethyl ether or normal nucleic acid solvent, filtered and dried to obtain poly [4- (4-hydroxyphenyl) pyruvicisopropanol methacrylate-hydroxyethyl meta as shown in the following formula (8). Acrylate-methyl methacrylate-glycidyl methacrylate] resin was obtained. Yield was 65 to 70% at this time.

(Example 7)

Synthesis of Poly [vinyl4- (2-butanone) benzoate-hydroxypropylacrylate-methylmethacrylate-glycidyl methacrylate] quapolymer

0.3 mol of vinyl 4- (2-butanone) benzoate, 0.25 mol of hydroxypropyl acrylate, 0.1 mol of methyl methacrylate, 0.3 mol of glycidyl methacrylate were placed in a 500 ml round bottom flask and stirred with 300 g of THF prepared in advance. When the mixture was mixed completely, 0.1 to 3.0 g of 2,2'-azobisisobutylonitrile (ABIN) was added thereto, and the reaction was carried out at a temperature of 60 ° C. to 75 ° C. for 5 to 20 hours under a nitrogen atmosphere. After completion of the reaction, the solution was precipitated in ethyl ether or normal nucleic acid solvent, filtered and dried to obtain a poly [vinyl4- (2-butanone) benzoate-hydroxypropylacrylate-methylmethacrylate represented by the following formula (9). -Glycidyl methacrylate] resin. Yield was 65 to 70% at this time.

(Example 8)

Synthesis of Poly [vinyl4- (3-methoxy) benzoateacetone-hydroxypropylmethacrylate-methylmethacrylate-glycidylmethacrylate] quapolymer

0.3 mol of vinyl 4- (3-methoxy) benzoate acetone, 0.23 mol of hydroxypropyl methacrylate, 0.1 mol of methyl methacrylate, 0.3 mol of glycidyl methacrylate are placed in a 500 ml round bottom flask and prepared beforehand while stirring. When 300 g of THF was added and completely mixed, 0.1 to 3.0 g of 2,2'-azobisisobutylonitrile (ABIN) was added thereto, and the mixture was reacted at a temperature of 60 ° C. to 75 ° C. for 5 to 20 hours under a nitrogen atmosphere. After completion of the reaction, the solution was precipitated in ethyl ether or normal nucleic acid solvent, filtered and dried to obtain a poly [vinyl4- (3-methoxy) benzoateacetone-hydroxypropyl methacrylate-methylmethane. Acrylate-glycidyl methacrylate] resin was obtained. The yield was at this time 65-70%.

Example 9) Preparation of Anti-Reflection Film

After dissolving the same resin as in Examples 5 to 8 having the basic structure of Formula 1 in propylene glycol methyl ethyl acetate (PGMEA), the filtered solution was applied to the wafer and hardbaked at 100-300 ° C for 10-1000 seconds. It was. Thereafter, a photosensitive film was applied and a fine pattern forming process was performed.

As described above, the polymer having the basic structure of Chemical Formula 1 according to the present invention not only contains a phenyl group having a high absorbance in the resin itself, but the antireflection film resin according to the present invention has excellent solubility in all hydrocarbon solvents. In addition, since it has a solvent resistance that does not dissolve in any solvent at the time of hard bake, it does not cause any problem when the photosensitive film is applied, and also shows an excellent effect of no undercutting and footing during pattern formation.

In particular, since the bonds of the crosslinked chains are made of C-O bonds, the etching selectivity is significantly improved by having an excellent etching rate compared to the ArF photosensitive film during etching.

Therefore, by using the polymer according to the present invention as an anti-reflection film in the ultra-fine pattern forming step of the semiconductor manufacturing process, not only the reflection of the lower layer layer in the lithography process of the semiconductor manufacturing process, but also the thickness of the light and photoresist itself By eliminating the standing wave caused by the change, stable ultrafine patterns of 1G, 4G, and 16G DRAMs can be formed, thereby increasing product yield.

Claims (13)

A compound of formula 1 (Formula 1) In the above formula, R _a , R _b , R _c and R _d each represent a hydrogen or methyl group, R ₁ to R ₄ are each hydrogen or substituted or unsubstituted straight or branched chain alkyl having 1 to 5 carbon atoms or alkoxy alkyl. In addition, w, x, y, z represents the mole fraction of 0.1-0.9, respectively, and l, m, n, p represents the integer of 1-3, respectively. The compound of claim 1, wherein R _a , R _c and R _d are each a methyl group, R _b is hydrogen, l, n, p are each 1, m are 2, and R ₁ , R ₂ , R ₃ and R ₄ are Poly [4- (4-hydroxyphenyl) pyruvicisopropanolmethacrylate-hydroxyethyl methacrylate-methylmethacrylate-glycol, each of hydrogen, w: x: y: z is 0.3: 0.25: 0.1: 0.3 Cydyl methacrylate]. A method of preparing a compound of Chemical Formula 2 by polymerizing a monomer having a structure of Chemical Formula 2, a hydroxyalkyl acrylate monomer, an alkyl acrylate monomer, and a glycidyl acrylate monomer with an initiator in a solvent. (Formula 2) Where R _a represents hydrogen or a methyl group, R ₁ to R ₄ each represent hydrogen or substituted or unsubstituted straight or branched chain alkyl having 1 to 5 carbon atoms or alkoxy alkyl, and p represents an integer of 1 to 3, respectively. The method of claim 3, wherein the initiator is selected from the group consisting of 2,2-azobisisobutylonitrile (AIBN), acetyl peroxide, lauryl peroxide and t-butyl peroxide. . The method of claim 3, wherein the solvent is selected from the group consisting of tetrahydrofuran, toluene, benzene, methylethylketone and dioxane. The method of claim 3 wherein the polymerization reaction is carried out at a temperature of 50 to 80 ℃. 4. The method of claim 3, wherein the molar ratio of each monomer is 0.1 to 0.9 mole each. A method of forming an anti-reflection film, characterized by comprising the step of applying a hard-baked solution of the compound of formula 1 in an organic solvent on a wafer. The method of claim 8, wherein the organic solvent is selected from the group consisting of ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, cyclohexanone, and propylene glycol methyl ether acetate. . The method of claim 8, wherein the amount of the organic solvent is characterized in that 200 to 5000% by weight of the compound of formula (1). The method of claim 8, wherein the hard bake is performed at a temperature of 100 to 300 ° C. for 10 to 1000 seconds. The composition for an anti-reflection film used in the manufacturing process of a semiconductor device, characterized in that comprising one of the compounds having the structure of formula (1). A semiconductor device comprising an antireflection film containing the antireflection film composition of claim 12.