KR100515485B1 - Organic bottom antireflective coating compositions for i-line photoresist - Google Patents

Abstract

The present invention relates to an organic anti-reflective coating composition for I-line photoresists comprising a compound represented by the following Chemical Formulas 1 and 2 having high absorbance and physical properties in the 365 nm wavelength region.

[Formula 1]

[Formula 2]

Wherein R ₁ to R ₁₅ are each independently or simultaneously a hydrogen atom; an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; a halogen atom; or a nitro group; a, b, c and d are 0, An integer of 1, 2, or 3; P ₁ , P ₂ , P ₃ , and P ₄ are each independently or simultaneously a hydrogen atom or an alkyl group having 1 to 4 carbon atoms)

Description

Organic anti-reflective coating composition for I-line photoresist {ORGANIC BOTTOM ANTIREFLECTIVE COATING COMPOSITIONS FOR I-LINE PHOTORESIST}

The present invention relates to an organic anti-reflective coating composition for I-line photoresist, and more particularly, to an organic anti-reflective coating composition compared to conventionally developed organic anti-reflective coating compositions using a resin in which a new light absorbing agent is combined and an additive for absorbing light. The organic anti-reflective coating for I-line photoresist has no low molecular sublimation material and has high absorption in 365nm area and can improve the pattern shape, resolution, focus tolerance and developability of photoresist. It relates to a composition.

The organic antireflection film is a chemical used in a semiconductor circuit process and is a coating material introduced to solve problems such as notching and standing wave of resist due to diffuse reflection of light generated in a photolithography process.

Although the process introduction and resist development for high integration of semiconductor circuits are continuously progressing, photolithography process using I-Line photoresist is used in the production of memory below 64 mega DRAM level or non-memory production process of medium and low level. The situation is ongoing. In addition, efforts have been made to reduce production costs and secure process stability by increasing the resolution of I-Line photoresist, which has already proven stability.

The critical resolution of the critical I-Line photoresist, whose name is subdivided, varies slightly depending on the exposure equipment, but the line width applicable to the process is 0.2 ~. It is about 0.25 micrometer. However, in the conventional exposure process, notching and standing wave phenomena occur, which causes problems of deterioration in size uniformity and poor resist pattern shape. The main cause of the notching and rectifying wave phenomena occurring in the exposure process is due to the difference in reflectance of the substrate caused by the step of the substrate which uses the semiconductor substrate as a metal layer or increases the thickness deviation of the resist. In order to solve the above problems by introducing a process to perform.

However, it is still insufficient to reliably implement the resist by sufficiently absorbing light in the 365 nm region to increase the limit resolution of the resist.

The present invention has been made to solve the problems of the prior art as described above, the present invention is to minimize the reflectance at the interface between the substrate and the resist by using a polymer and a light absorption additive combined with a new light absorbing agent in the organic anti-reflection film It is an object of the present invention to provide an I-line photoresist organic antireflective coating composition which maintains uniformity of line width and supports a lot of focus tolerance.

Another object of the present invention is to provide an I-line photoresist organic anti-reflective coating composition which can minimize the process line contamination by sublimation by solving the low molecular sublimation problem generated during the organic anti-reflective coating curing process.

In order to achieve the above object, the present invention provides a chalcone derivative compound for light absorbers represented by the following formula (3).

[Formula 3]

In Formula 3, R ₁ to R ₉ are each independently or simultaneously hydrogen atoms; An alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; Halogen atom; Or nitro group.

In addition, the present invention provides a method for preparing a chalcone derivative compound for a light absorber represented by the following formula (3) comprising the step of nucleophilic substitution reaction of the compound represented by the following formula (4) and chloride methacrylate.

[Formula 3]

[Formula 4]

In the formulas (3) and (4), R ₁ to R ₉ each independently or simultaneously represent a hydrogen atom; An alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; Halogen atom; Or nitro group.

In addition, the present invention provides a polymer resin for an organic antireflection film represented by the following formula (1).

[Formula 1]

In the formula of Formula 1,

R ₁ to R ₉ are each independently or simultaneously a hydrogen atom; An alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; Halogen atom; Or a nitro group;

a, b, c and d are integers equal to 0, 1, 2, or 3;

P ₁ , P ₂ , P ₃ , and P ₄ are each independently or simultaneously a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

In addition, the present invention

a) iii) a chalcone derivative compound for light absorbers represented by the formula (3), ii) hydroxy ethyl acrylate monomer, iii) glycidyl acrylate monomer, iii) methyl acrylate monomer, and iii) initiator in an organic solvent. Radical polymerization by addition; And

b) precipitating the reaction mixture with methanol and removing the solvent

It provides a method for producing a polymer resin for organic antireflection film represented by the formula (1) comprising a.

In addition, the present invention is an organic anti-reflective coating composition for I-line photoresist,

a) an organic antireflective polymer resin represented by Chemical Formula 1; And

b) Additive for light absorption represented by the following formula (2)

It provides an organic antireflection film composition for I-line photoresist comprising a.

[Formula 1]

[Formula 2]

In Formulas 1 and 2,

R ₁ to R ₁₅ are each independently or simultaneously a hydrogen atom; An alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; Halogen atom; Or a nitro group;

a, b, c and d are integers equal to 0, 1, 2, or 3;

P ₁ , P ₂ , P ₃ , and P ₄ are each independently or simultaneously a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

The present invention also provides an organic antireflection film for an I-line photoresist prepared by including the organic antireflection film composition described above.

Hereinafter, the present invention will be described in detail.

As described above, as the resist performance is rapidly developed due to the high integration of semiconductor circuits, the limit resolution of the resist in the photolithography process using the 365 nm exposure equipment is continuously improved, and the line width that can be resolved using the I-Line photoresist is obtained. The photoresist performance using a 365 nm wavelength is gradually increasing so that the resolution range is widened from 0.2 to 0.25 micrometer.

Therefore, the present inventors solve the sublimation and coating defects of the dye constituting the organic anti-reflection film on the wafer, which is a problem that occurs when applying the organic anti-reflection film to the sub-layer in the photolithography process and thermal curing, Absorption of diffuse reflection light generated at the interface between resist and sub-layer during exposure to minimize diffuse reflection and standing wave phenomena to solve the pattern pattern defect and the decrease in line width uniformity of photoresist Development of new light absorption additives and polymer resins as constituents that influence the performance of organic anti-reflective coatings that can maximize the margin of focus (DOF) and exposure latitude (EL) To complete.

In the organic anti-reflective coating composition for I-line photoresists of the present invention, each component constituting the composition will be described in more detail as follows.

Chalcone Derivative Compounds for Light Absorbers

The chalcone derivative compound used as the light absorbing agent in the present invention is a compound represented by Chemical Formula 3, which is a light absorbing monomer represented by Chemical Formula 4 having high absorption in a 365 nm wavelength region due to a conjugated bond between a carbonyl group and a benzene ring. It is prepared through synthesis. That is, the compound of Formula 3 is connected to the benzene ring by conjugated bonds in order to increase the absorbance in the 365 nm region, introducing a chalcone derivative compound having a high oxygen atom content in the molecule to improve the etching rate of the organic anti-reflection film, radical It is prepared by introducing a methacryl group to enable polymer synthesis by polymerization.

The present invention, as shown in Scheme 1, by reacting the hydroxy group and the chlorinated methacrylate of the chalcone derivative of the formula (4) through a nucleophilic substitution reaction using a hydroxy group in the chalcon derivative compound To prepare a chalcone derivative compound for light absorbers of formula (3) substituted with methacrylate.

Scheme 1

In Scheme 1, R ₁ to R ₉ are each as defined above.

The compound of formula (4), which is a chalcone derivative compound monomer (light absorbing monomer) used in the present invention, is basically a methacrylate in which a double bond is introduced, since the polymer should be synthesized by radical polymerization, and has sufficient light in a 365 nm wavelength region. It contains a compound of the chalcone derivative consisting of a conjugated bond to absorb. The light absorbing monomer serves as a light absorbing agent in the organic anti-reflective film to reduce the diffuse reflection and standing wave phenomenon of light in the photolithography process and excellent etching selectivity. The light absorber monomer of Chemical Formula 4 may be prepared using acetobanilone, 4-methoxybenzene aldehyde, tetramethyl ammonium hydroxide, and ethanol.

The amount of the chlorinated methacrylate is preferably 1 to 2.5 mol based on 1 mol of the chalcone derivative compound. In the present invention, in order to neutralize the hydrochloric acid generated during the substitution reaction, basic reactants such as triethylamine and pyridine can be used. The amount of the basic reactant is preferably used in 1 to 2.5 mol with respect to the compound in the chalcone derivative which is the initial reactant.

At this time, R ₁ to R ₉ of Chemical Formula 3 are each independently or simultaneously hydrogen atoms; Or an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms.

Polymer resin combined with light absorber

The present invention prepares an acrylate-based polymer resin represented by Chemical Formula 1, which is a new polymer material used for an organic antireflection film, using the compound for the light absorbing compound of Chemical Formula 3 prepared above as a monomer.

The polymer resin of Chemical Formula 1 is a chalcone derivative compound of Chemical Formula 3 containing a light absorbing agent, hydroxy ethyl acrylates, glycidyl acrylates, and organic to perform a crosslinking role in the production of an organic antireflection film It can be prepared through a radical polymerization reaction using a methyl acrylate monomer to increase the solubility in the solvent used in the anti-reflection film and to improve the adhesion to the substrate. At this time, initiators used in radical polymerization include benzoyl peroxide, azoisobutyronitrile (AIBN) and 2,2'-azobis (2,4-dimethylvalenonitrile) (trade name: V-65). Preferably, azoisobutyronitrile (AIBN) is used.

The amount of the reaction solvent used in the synthesis of the polymer resin is preferably used in an amount of 200 to 1000 parts by weight based on 100 parts by weight of the reaction raw material. In addition, the reaction temperature during the polymerization reaction can be controlled by the reactivity of the raw material is preferably 50 to 80 ℃.

The present invention is to remove the reaction raw materials, initiators, reaction solvents and the like remaining after the completion of the polymerization reaction, the present invention is methanol, ether, or hexane in an amount of 1500 to 5000 parts by weight based on 100 parts by weight of the reaction raw material After the polymerization is completed, the filtered reaction mixture is precipitated, and washed three times or more using a precipitation solvent, thereby obtaining an acrylate resin having a light absorber bound thereto.

In this case, R ₁ to R ₉ of Chemical Formula 1 are each independently or simultaneously hydrogen atoms; Or an alkyl or alkoxy group having 1 to 4 carbon atoms.

It is preferable that the weight average molecular weight of the acrylate resin of the said General formula (1) used by this invention is 10,000-1,000,000, More preferably, it is 15,000-500,000, More preferably, it is 20,000-50,000.

Organic Anti-reflective Coating Composition

The present invention provides an organic antireflective coating composition for I-line photoresist using the compound represented by Chemical Formula 1 prepared through the above process.

The organic antireflection film composition of the present invention includes a polymer resin in which the light absorbing agent of Formula 1 is bonded, and an additive for absorbing light represented by the following Formula 2. In addition, the organic anti-reflective coating composition of the present invention may further include an organic solvent, a thermal acid generator, a crosslinking agent, and the like.

[Formula 2]

In formula (2), R ₁₀ to R ₁₅ are each independently or simultaneously a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, or a nitro group; a, b, c and d are integers equal to 0, 1, 2, or 3; P ₁ , P ₂ , P ₃ , and P ₄ are each independently or simultaneously a hydrogen atom or an alkyl group.

The content of the polymer resin of Chemical Formula 1 is preferably used in an amount of 1 to 20% by weight based on the total composition. When the amount of the polymer resin is less than the above range, the diffused light generated in the photolithography process cannot be sufficiently absorbed. When the amount of the polymer resin used exceeds the above range, the solubility in the solvent used in the organic anti-reflective coating decreases, the coating uniformity deteriorates, and the content of molecules composed of benzene rings having a large number of carbon and carbon bonds in the composition There is a problem that the etching rate is slowed during the organic anti-reflective coating etching process is large, thereby causing a resist thickness loss.

In addition, the content of the light absorbing additive of the formula (2) is preferably used in 1 to 20% by weight based on the total composition, when the content of the light absorbing additive exceeds the outside of the range contained in the light absorbing additive The amount of the hydroxyl group is increased in the antireflective coating composition, so that the organic antireflection coating is delaminated by the alkaline developer and partially melts the resist pattern collapse when the resist is developed after the exposure process.

In addition, the content of the organic solvent, thermal acid generator and crosslinking agent may be used in the conventional content used in the organic anti-reflective coating composition.

In the present invention, the antireflective coating composition is applied to a silicon wafer or various metal substrates using spin coating to form an antireflection coating. At this time, in order to remove the residual solvent and crosslink by thermosetting, the antireflection film is heated to 190 to 240 ° C after coating. Thereafter, a resist is applied, subjected to an exposure process, and developed with a developer to implement a pattern.

As the developer used in the present invention, an alkaline aqueous solution in which alkaline compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate and tetramethyl ammonium hydroxide are dissolved to be 0.1 to 10% by weight is used. An appropriate amount of a water-soluble organic solvent such as methanol and ethanol and a surfactant can be added to the developer. After developing with the developer which consists of this alkaline aqueous solution, it wash | cleans with ultrapure water.

The organic antireflective film of the present invention thus obtained contains a light absorbing agent to prevent notching due to diffuse reflection in the substrate generated during the exposure process, and to prevent standing wave phenomenon in the form of a resist pattern. In addition to improving resolution and preventing pattern collapsing, the high oxygen content of the light absorber can minimize resist damage during the etching process.

Hereinafter, the present invention will be described with reference to the following Examples and Comparative Examples. However, these examples are only for illustrating the present invention, and the present invention is not limited thereto.

EXAMPLE

Example 1

Synthesis of Light Absorber Monomer: Preparation of 4-methoxy benzylidene 4'-hydroxy-3'-methoxy acetophenone (Compound 4)

100 g of acetovanillones

164 g of 4-methoxybenzene aldehyde

100 g of 20% tetramethyl ammonium hydroxide aqueous solution

500 g of ethanol

Acetovanilone and 4-methoxybenzene were dissolved in ethanol in a 2 L round flask, and a 20% tetramethyl ammonium hydroxide aqueous solution was slowly added dropwise at room temperature, and a light absorber monomer was prepared under stirring for 12 hours.

Example 2

Synthesis of Chalcone Derivative Compounds Used as Light Absorbers: Preparation of 4-methoxy benzylidene 4'-methacryloxy-3'-methoxy acetophenone (Compound 3)

32 g of 4-methoxy benzylidene 4'-methacryloxy-3'-methoxy acetophenone

Chlorinated methacrylate (MACl) 15 g

11.4 g of triethylamine (TEA)

Tetrahydrofuran (THF) 160 g

4-methoxy benzylithene 4'-methacryloxy-3'-methoxy acetophenone and triethylamine are completely dissolved in anhydrous tetrahydrofuran (THF), and the chlorinated methacrylate solution dissolved in tetrahydrofuran is reacted with a reaction vessel. Slowly added dropwise into the mixture and stirred at room temperature for 4 hours to prepare a chalcone derivative compound.

Example 3

Preparation of Methaacrylate Resin (Compound 1) Incorporated with Chalcone Derivatives

20 g of 4-methoxy benzylidene 4'-methacryloxy-3'-methoxy acetophenone

Glycidyl Methacrylate (GMA) 3.67 g

2.02 g of 2-hydroxyethyl methacrylate (2-HEMA)

Methyl methacrylate (MMA) 521 mg

Azobisbutyronitrile (AIBN) 786 mg

Tetrahydrofuran (THF) 131 g

The compounds were placed in a round flask and the temperature was raised to 65 ° C. while stirring to polymerize for 4 hours. After the reaction, the reaction mixture was cooled to room temperature to stop the polymerization, and the remaining reaction raw material and reaction solvent were removed by precipitation using methanol to obtain a resin.

Example 4

Preparation of Organic Antireflection Film Composition

10 g of acrylate polymer resin

10 g of 2,2,4,4-tetrahydroxy benzophenone

0.1 g of 2-hydroxycyclohexyl p-toluenesulfonated ester

3 g of hexamethoxymethyl melamine

300 g of cyclohexanone (CH)

10 g of the acrylate-based polymer resin prepared in Example 3 and 10 g of 2,2,4,4-tetrahydroxy benzophenone, which are additives of Formula 2, are dissolved in cyclohexane, which is a solvent, and other thermal acids of conventional content. An organic anti-reflective coating composition was prepared by adding a generator and a crosslinking agent.

(Physical Characteristic Test on Oil-Based Sand Bar)

Experimental Example 1

Thickness Loss of Organic Anti-reflective Coatings on Photoresist Solvents

The organic anti-reflective coating composition was spin-coated at 4000 rpm on a 3-inch silicon wafer, and then heated to 180 ° C. for 90 seconds. The coated sample was spun at 5000 rpm for 30 seconds on an organic antireflective coating sample coated with photoresist solvent 2-heptanone, ethyl lactate (EL), and propylene glycol monomethyl ether acetate (PGMEA) for 60 seconds. After treatment at 100 ° C. on a heating substrate, the thickness loss of the organic anti-reflective coating film before and after photoresist solvent treatment was investigated and the results are shown in Table 1 below.

Loss Assessment of Photoresist Solvents in Organic Reflective Films Resist solvent Organic Anti-Reflection Thickness (두께) Thickness difference Before treatment After treatment 2-heptanone 1453 1452 One Ethyl lactate 1422 1420 2 Propylene Glycol Monomethyl Ether Acetate 1436 1436 0

As shown in Table 1, in the case of using the organic anti-reflective coating composition of the present invention, considering that the difference in thickness of the organic anti-reflective coating film is within the range of thickness deviation (± 5Å) generated during coating to 0 ~ 2Å, resist There was no loss of the thickness of the organic anti-reflective coating of the present invention with respect to the solvent.

In addition, FIG. 1 shows an electron micrograph of a photoresist pattern shape after (A) coating an organic antireflection film on a metal substrate and a photoresist pattern shape without applying an organic antireflection film on (B) a metal substrate. In Figure 1, it can be seen that when applied using the organic anti-reflective coating composition of the present invention, the shape of the photoresist pattern is superior to that of not applied.

Experimental Example 2

Reflectance measurement

After spin coating an antireflective coating composition on a 3 inch silicon wafer at 4000 rpm, the substrate was heated at 180 ° C. for 90 seconds on a heating substrate, and the refractive index of the wafer coating coated with the organic antireflection coating was measured. Reflectance of each thickness of the organic anti-reflective coating was measured. As shown in FIG. 2, the reflectance was the lowest as 0.009% at 1040 kHz and a sufficient value of less than 5% of the reflectance of the organic anti-reflective coating that can be used in the I-Line process for a thickness of 1500 Å or more can be seen.

As described above, the organic anti-reflective coating composition for I-line photoresist according to the present invention has no low-molecular sublimation material generated when the organic anti-reflective coating is cured compared to conventional organic anti-reflective coating compositions when used in a photolithography process and has a 365 nm region. It has high absorbency at and can improve the pattern shape, resolution, focus tolerance and developability of the photoresist well.

1A is an electron micrograph of a photoresist pattern after applying the organic antireflective coating composition of the present invention to a metal substrate,

1B is an electron micrograph of a photoresist pattern in which an organic antireflective coating is not applied on a metal substrate.

Figure 2 shows the reflectance simulation for the organic antireflection film.

Claims (11)

Chalcone derivative compounds for light absorbers represented by the following formula (3): [Formula 3] In formula (3), R ₁ , R ₂ , R ₄ to R ₆ , R ₈ and R ₉ are each independently or simultaneously a hydrogen atom, an alkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms, a halogen atom, Or a nitro group, and R ₃ and R ₇ are each a methoxy group. According to claim 1, wherein in Formula 3 R ₂ , R _{4 To} R ₆ , R ₈ And R ₉ are each independently or simultaneously hydrogen atom; Or an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and R ₃ and R ₇ are each a methoxy group. Method for preparing a chalcone derivative compound for light absorbers represented by the following formula (3) comprising the step of nucleophilic substitution reaction of 1 to 2.5 moles of chloride methacrylate with respect to 1 mole of the compound represented by formula (4):  [Formula 3] [Formula 4] In Formulas 3 and 4, R ₁ , R ₂ , R ₄ to R ₆ , R ₈ and R ₉ are each independently or simultaneously a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom , Or a nitro group, and R ₃ and R ₇ are each a methoxy group. A polymer resin for organic antireflection film represented by the following formula (1): [Formula 1] In the formula of Formula 1, R ₁ to R ₉ are each independently or simultaneously a hydrogen atom; An alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; Halogen atom; Or a nitro group; a, b, c and d are integers equal to 0, 1, 2, or 3; P ₁ , P ₂ , P ₃ , and P ₄ are each independently or simultaneously a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The method according to claim 4, wherein in Formula 1 R _{One To} R _{9 Are} each independently or simultaneously hydrogen atom; Or an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. 5. The polymer resin for organic antireflection film according to claim 4, wherein the polymer resin is a polyacrylate resin having an average molecular weight of 10,000 to 1,000,000. a) iii) a chalcone derivative compound for light absorbers represented by the following formula (3), ii) hydroxy ethyl acrylate monomer, iii) glycidyl acrylate monomer, iii) methyl acrylate monomer, and iii) initiator in an organic solvent. Radical polymerization by addition; And b) precipitating the reaction mixture with methanol and removing the solvent Method for producing a polymer resin for organic antireflection film represented by the formula (1) comprising: [Formula 1] [Formula 3] In Formulas 1 and 3, R ₁ to R ₉ are each independently or simultaneously a hydrogen atom; An alkyl or alkoxy group having 1 to 4 carbon atoms; Halogen atom; Or a nitro group; a, b, c and d are integers equal to 0, 1, 2, or 3; P ₁ , P ₂ , P ₃ , and P ₄ are each independently or simultaneously a hydrogen atom, an alkyl group having 1 to 4 carbon atoms. In the organic anti-reflective coating composition for I-line photoresist, a) an organic antireflective polymer resin represented by Chemical Formula 1; And b) Additive for light absorption represented by the following formula (2) Organic anti-reflective coating composition for I-line photoresist comprising: [Formula 1] [Formula 2] In Formulas 1 and 2, R ₁ to R ₁₅ are each independently or simultaneously a hydrogen atom; An alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; Halogen atom; Or a nitro group; a, b, c and d are integers equal to 0, 1, 2, or 3; P ₁ , P ₂ , P ₃ , and P ₄ are each independently or simultaneously a hydrogen atom, an alkyl group having 1 to 4 carbon atoms. The method of claim 8, wherein the organic anti-reflective coating composition is a) 0.1 to 20% by weight of the polymer resin of Formula 1; And b) 0.1 to 20% by weight of an additive for absorbing light of formula (2). The organic antireflection film composition for I-line photoresist according to claim 8, wherein the polymer resin is a polyacrylate resin having an average molecular weight of 10,000 to 1,000,000. An organic antireflection film for an I-line photoresist, comprising the organic antireflection film composition according to claim 8.