KR100889173B1 - Organic Copolymer for preparing Organic Antireflective Coating, Method of Preparing the same, and Composition comprising the same - Google Patents

Abstract

The present invention provides an anti-reflective coating for use in ultrafine circuit processing using ultra-ultraviolet rays in the manufacture of semiconductor devices, and a method for preparing the same, and an organic anti-reflective coating composition containing the polymer It is about.

When the organic anti-reflective coating using the cyanato crosslinking end-containing copolymer according to the present invention is used in the manufacture of highly integrated devices of gigabit DRAM, the adhesion to the substrate is improved and the interlayer reflection and the standing wave of the circuit are suppressed to improve 70nm to 150nm class. It is possible to stably form a high-resolution microcircuit of to increase the production yield of the semiconductor device.

Organic antireflection film, cyanaito crosslinked group-containing copolymer, adhesion, maleimide

Description

Organic Copolymer for preparing an organic antireflection film, a method for preparing the same and a composition comprising the same {Organic Copolymer for preparing Organic Antireflective Coating, Method of Preparing the same, and Composition comprising the same}

The present invention, in photolithography, which is an exposure process for forming a microcircuit of a highly integrated semiconductor using short-wavelength ultraviolet light, suppresses the reflective notching occurring in the substrate layer under the photoresist, Cyanate crosslinking end-containing organic copolymer for bottom antireflective coating layer capable of removing the standing wave effect due to the change in thickness of the resist, a manufacturing method thereof, and an antireflective coating composition comprising the same .

Antireflective coating (ARC) is a very thin layer of light-absorbing photosensitive material, processing optical microcircuits to reliably form ultrafine circuits of 70nm to 150nm and below, which are essential for producing gigabit (Gb) class ultra-high density semiconductors. Used in the process. Therefore, the anti-reflection film should be well matched with the high-resolution photoresist (PR) materials used in the existing semiconductor production process and mutual adhesion interface and optical properties. Since the anti-reflection film is first applied to the bottom of the photoresist layer during the ultraviolet exposure process, it is called a bottom anti-reflection film (BARC, bottom ARC). It is commonly used. Since the organic antireflection film must have high light absorption at a specific exposure wavelength, it must be able to cope with shortening of the light source (G-line, I-line, KrF, ArF, F2, etc.) according to the development of highly integrated semiconductor micromachining process. [M. Padmanaban et al., Proc. SPIE, 3678, 550 (1999); G. E. Bailey et al. Proc. SPIE, 3999, 521 (2000); M. Padmanaban et al., Proc. SPIE, 333, 206 (1998).

Recently, the technology of the ultra-high density semiconductor manufacturing process has developed remarkably, but the conventional optical fine processing technology that rotates and exposes the photoresist, a photoresist material, on the silicon wafer to expose the stable micro-circuit of 70-150nm class It became impossible. Therefore, it is necessary to apply a special thin film to prevent reflection in the exposure process before applying the photoresist layer. The anti-reflection film prevents standing wave effects caused by interference of incident light and reflected light from the substrate inside the photoresist layer during exposure, and also prevents reflection or corners due to topography resulting from circuit layers made in conventional processes. It acts to prevent or significantly reduce diffuse reflection. Therefore, precise control of the desired critical circuit dimensions (CD) serves to increase the process latitude of the manufacturing process conditions. The anti-reflection film has an organic substance based on its composition and an inorganic substance using chemical vapor deposition. However, in recent years, most of the anti-reflective membranes which are convenient for the process are used.

The role of the anti-reflective film became more important after short-wavelength ultraviolet processing, especially after the process of optical microcircuit processing using a ktnm fluoride (KrF) excimer laser having a wavelength of 248 nm, became more important. For this purpose, organic polymer antireflection film materials using chromophore-containing aromatic derivatives such as anthracene or naphthalene having high absorbance in the far ultraviolet region are widely used [J. Meador et al., Proc. SPIE, 3678, 800 (1999); G. Taylor et al., Proc. SPIE, 3678, 174 (1999); X. Shao et al., J. Photopolym. Sci. Techonol., 14, 481 (2001); Myoung Soo Kim et al., Proc. SPIE, 5753, 644 (2005); K. Mizutani et al., Proc. SPIE, 3678, 518 (1999). Such techniques are disclosed in US Pat. Nos. 5693691, 5886102, 5919599, 6033830, 6080530, 6156479 and 6602652.

Organic bottom anti-reflective coatings used in the ultra-violet exposure process for the fabrication of ultra-fine circuits must meet several requirements, such as [H. Yoshino et al., Proc. SPIE, 3333, 655 (1998); P. Trefonas et al., Proc. SPIE, 3678, 701 (1999); S. Malik et al., J. Photopolym. Sci. Techonol., 14, 489 (2001); R. Huang et al., Proc. SPIE, 5753, 637 (2005); C. Y. Chang et al., Proc. SPIE, 6153, 61530M (2006).

Have a refractive index (n) and a light absorption constant (k), which are optical constants suitable for light sources used in semiconductor manufacturing.

-It should have a high selectivity at the plasma dry etch rate compared to the upper photoresist and there should be no defects caused by dry etch.

No intermixing should occur between the photoresist layer and the antireflective layer, which requires the inclusion of a reactor capable of forming an appropriate crosslinked structure in the organic polymer chain.

In the film forming process by rotating coating, suitable thin film thickness control ability, excellent film forming ability and film uniformity are required.

An object of the present invention is a cyanide which can be used in an ultrafine circuit exposure process that is used as a clipton fluoride (KrF) having a wavelength of 248 nm and an argon fluoride (ArF) excimer laser exposure source having a wavelength of 193 nm in an ultra-high density semiconductor device manufacturing process. It is to provide a novel organic copolymer containing a cyanato cross-linker and a method for producing the same.

Another object of the present invention is to provide an organic polymer material which can prevent diffuse reflection from an underlayer during a short wavelength exposure process and has excellent adhesion and crosslinking performance, and a method of manufacturing the same.

Still another object of the present invention is to provide a bottom antireflective coating composition using the organic polymer material and a bottom antireflection film thereby.

The organic polymer for bottom antireflective coating according to the present invention has properties of monomers and polymers containing anthracene chromophore and hydroxyphenylmaleimide chromophore, which cause high light absorption at exposure wavelengths of 248 nm and 193 nm, and cyanate groups for crosslinking when antireflection film is formed. Terpolymers to pentagonal copolymers prepared from three or four different monomers, such as comonomers, to control these compounds. In particular, the hydroxyphenylmaleimide monomer used in the preparation of the organic polymer of the present invention is preferably a monomer having a properly protected chemical structure or crosslinking function for ease of manufacturing the polymer. The organic polymer for a bottom anti-reflection film according to the present invention, which satisfies all the above characteristics, has a structure as shown in the following formula (1).

Wherein R is H, tetrahydropyranyl, -COOR 5, -Si (R 6) ₃ or a t-butyl group, where R 5 and R 6 are each a methyl group, a t-butyl group or an alkyl group having 2 to 3 carbon atoms,

R1 and R3 are each hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxyalkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group or halogenated alkyl group having 1 to 6 carbon atoms,

R2 and R4 are each hydrogen or a methyl group,

The ratio of each monomer is based on the total mole fraction k + l + m + n of the monomer, the mole fraction of k is 0 to 0.3, the mole fraction of l is 0 to 0.7, the mole fraction of m is 0.1 to 0.5, and the mole fraction of n is 0.1 to 0.4, where the mole fraction of k may be two N-phenylmaleimide monomers represented by k.

The organic polymer of the present invention having the structure shown in Chemical Formula 1 may generally be represented as (Ma) k- (Mb) l- (Mc) m- (Md) l. Wherein Ma represents a N- (4-hydroxyphenyl) maleimide structure protected with hydroxyphenylmaleimide, precisely N- (4-hydroxyphenyl) maleimide or a suitable protecting group such as represented by R in Formula 1 Mb is a methacrylic acid ester structure having a suitable functional group as represented by R1 in Formula 1, Mc has an N- (4-cyanatophenyl) maleimide structure having a crosslinking function, and Md has a light absorption function 9-anthracenemethylmethacrylate having

In comparison with the conventional hydroxy-based cross-linked derivatives, the cyanato-crosslinked cross-linked polymer of Formula 1 according to the present invention significantly increases the adhesion to the wafer and has excellent crosslinkability with the intermixing with the photoresist layer. Prevents an improved coating film forming ability.

Next, the manufacturing method of the polymer of the present invention as shown in the general formula (1) will be described. The polymer of Chemical Formula 1 may be obtained by reacting for 2 hours to 24 hours using a radical polymerization initiator under an inert gas atmosphere such as nitrogen and arcon according to a conventional radical polymerization method. The radical polymerization initiator may be selected from known thermal polymerization initiators such as azobisisobutyronitrile (AIBN), azobisvaleronitrile (AIVN), benzoyl peroxide (BPO), di-t-butyloxide (DTBP), and the like. It may be used, the reaction temperature is preferably in the range of 50 ℃ to 90 ℃. As a solvent of a polymerization reaction, aromatic solvents, such as dioxane, tetrahydrofuran, or benzene, can be used. In the present invention, by adjusting the weight ratio between the monomer and the polymerization solvent or by controlling the amount of the radical initiator, it is possible to produce a polymer of the appropriate molecular weight required in the semiconductor exposure step. The molecular weight of the polymer of Chemical Formula 1 is controlled by controlling the polymerization conditions, so that the molecular weight measured by gel permeation chromatography (GPC) is in the range of 5,000 to 100,000. Among the polymers obtained by the same method as described above, a polymer having a molecular weight having an appropriate coating ability is used as the antireflection film material.

Next, the composition for organic antireflection films concerning this invention is demonstrated. The organic antireflective coating composition of the present invention comprises the polymer of Formula 1 as a solvent for propylene glycol monomethyl ether acetate (PGMEA), ethyl 3-ethoxypropionate, ethyl lactate, methyl 3-methoxy It is prepared by dissolving 0.2 to 20% by weight in an organic solvent having excellent film forming ability such as propionate or cyclohexanone, and then adding various functional additives to the solution as appropriate. At this time, the content of each additive is 0.1 to 10% by weight of the crosslinking agent and the like with respect to the polymer used.

The mixed solution at the above ratio is filtered in a fine particle filtration apparatus, spun applied on a silicon wafer, and crosslinked at an appropriate temperature to obtain a desired antireflection film. The anti-reflection film prepared in this manner serves to remove the problems caused by the reflection of light in the short wavelength far ultraviolet microcircuit processing process, so that the semiconductor device can be produced smoothly.

The cyanato-crosslinked end-containing antireflective polymer according to the present invention showed excellent performance as an organic antireflective film for forming a microcircuit in the exposure wavelength region of short wavelength far ultraviolet rays of 248 nm, 193 nm, and 157 nm, and was based on a conventional hydroxy crosslinked end. Since it has excellent adhesiveness and crosslinkability compared to the antireflection film, it has been found to be useful for the formation of ultrafine circuits in the formation of semiconductor devices.

Hereinafter, the present invention will be described in detail through examples. However, the embodiments are only illustrative of the present invention, and the scope of the present invention is not limited thereto.

Example  1.N- Hydroxyphenylmaleimide ( HOPMI Synthesis of Monomer 1

In a 250 ml round bottom flask equipped with a reflux condenser, maleic anhydride (39.20 g, 0.40 mol) and 4-aminophenol (41.40 g, 0.38 mol) were placed in 50 ml of dimethylformamide (hereinafter referred to as DMF). It was dissolved and reacted at room temperature for 90 minutes. After the reaction, the resulting yellow solid product was filtered, washed 3-4 times with distilled water and dried to form N -hydroxyphenylmaleamic acid (hereinafter referred to as N- (4-hydroxyphenyl) maleamic acid, hereinafter referred to as HOPMA) 75. 40 g (Yield 96.0%) was obtained and its melting point was 180 deg.

Subsequently, the resulting HOPMA (75.40 g, 0.36 mol) was placed in a 250 ml round bottom flask equipped with a reflux condenser and reacted at 80 ° C. while slowly adding phosphorus pentoxide (P 2 O 5, 10.0 g, 0.07 mol) to produce water as a side reaction. After removing the solution, a solution of diluting 4 ml in terms of 20 ml of DMF was slowly added dropwise to the reaction mixture. The reaction product formed by reacting for 2 hours was precipitated in excess distilled water to obtain a monomer product, which was then recrystallized from propanol to obtain 56.37 g of pure N -hydroxyphenylmaleimide (hereinafter referred to as HOPMI) monomer 1 of orange crystals (yield 81.9). %) And the melting point was 182 ° C.

Example  2.N- (4- Tetrahydropyranyloxyphenyl ) Maleimide ( THP - OPMI Synthesis of Monomer 2

In a 500 ml round bottom flask, monomer 1 (47.30 g, 0.25 mol) and dihydropyran (105.20 g, 1.25 mol) were added and dissolved in 150 ml of tetrahydrofuran (hereinafter referred to as THF). 0.5 ml of concentrated sulfuric acid was diluted in 100 ml of THF and slowly added dropwise to the reaction, followed by stirring at room temperature for 12 hours. After completion of the reaction, the solvent was distilled off under reduced pressure, and the remaining product was precipitated in excess distilled water, and the resulting precipitate was filtered and washed with distilled water several times. The product was recrystallized in propanol to give 53.20 g (yield 77.9%) of N -tetrahydropyranyloxymaleimide (THP-OPMI) monomer 2 , a protected monomer of orange crystals, with a melting point of 120 ° C.

Example  3.N- (4- Cyanatophenyl ) Maleimide ( CyPMI Synthesis of Monomer 3

In a 250 ml round bottom flask, monomer 1 (15.00 g, 0.79 mol) and cyanozen bromide (10.10 g, 0.95 mol) were dissolved in 120 ml of acetone, cooled in an ice bath at 0 ° C. and triethylamine (9.60 g, 0.95 mol) was slowly dropped for 20 minutes and then reacted for 4 hours. The resulting reaction was filtered to remove the ammonium salt and the filtrate was precipitated in excess distilled water to recover the product. The product was recrystallized in a mixture of hexane and acetone (6: 1) to obtain 13.74 g (yield 80.90%) of N -cyanatophenylmaleimide (hereinafter referred to as CyPMI) monomer 3 as an orange crystal, and the melting point was 132 ° C. It was.

Example  4. Monomer 3 , Anthracene Methyl methacrylate , methyl Methacrylate  Used Terpolymer  synthesis

In the polymerization vessel, monomer 3 (7.84g, 36mmol), anthracene methylmethacrylate (hereinafter referred to as AMMA, 10.22g, 36mmol), methyl methacrylate (hereinafter referred to as MMA, 7.32g, 72mmol) and AIBN 3mol as a radical initiator % Was dissolved in dioxane (50 ml), and the polymerization was carried out at a polymerization temperature of 60 ° C. for 10 hours under a nitrogen atmosphere. The polymerization reactant was precipitated in excess methanol, and then filtered and dried to synthesize P (CyPMI / AMMA / MMA), a terpolymer. The yield of obtained P (CyPMI / AMMA / MMA) was 86%, and the film shape was easy about 43,000 as a weight average molecular weight as a result of molecular weight measurement by GPC.

Example  5. Monomer 1, Monomer 3 , AMMA , MMA Using Employee Copolymer  synthesis

Into the polymerization vessel, monomer 1 (7.11g, 36mmol), monomer 3 (7.84g, 36mmol), AMMA (10.22g, 36mmol), MMA (7.32g, 72mmol) and 3 mol% of AIBN, a radical initiator, dioxane (50ml) The solution was dissolved in, followed by polymerization at a polymerization temperature of 60 ° C. for 10 hours under a nitrogen atmosphere. The polymerization reactant was precipitated in excess methanol, and then filtered and dried to synthesize P (HOPMI / CyPMI / AMMA / MMA). The yield of obtained P (HOPMI / CyPMI / AMMA / MMA) was 88%, and the film shape was easy about 41,000 as a result of the molecular weight measurement by GPC.

Example  6. monomer 2, Monomer 3 , AMMA , MMA Using Employee Copolymer  synthesis

Into the polymerization vessel, monomer 2 (10.0g, 36mmol), monomer 3 (7.84g, 36mmol), AMMA (10.22g, 36mmol), MMA (7.32g, 72mmol) and 3 mol% of AIBN, a radical initiator, dioxane (50ml) The solution was dissolved in, followed by polymerization at a polymerization temperature of 60 ° C. for 10 hours under a nitrogen atmosphere. The polymerization reaction was precipitated in excess methanol, and then filtered and dried to synthesize P (THP-OPMI / CyPMI / AMMA / MMA). The yield of obtained P (THP-OPMI / CyPMI / AMMA / MMA) was 91%, and the film shape was easy about 42,500 as a weight average molecular weight as a result of molecular weight measurement by GPC.

Example  7. Monomer 1, Monomer 2, Monomer 3 , AMMA , MMA Using Oone copolymer  synthesis

In the polymerization vessel, monomer 1 (7.11g, 36mmol), monomer 2 (10.0g, 36mmol), monomer 3 (7.84g, 36mmol), AMMA (10.22g, 36mmol), MMA (7.32g, 72mmol) and radical initiator 3 mol% of AIBN was added thereto, dissolved in dioxane (50 ml), and then polymerized under a nitrogen atmosphere at a polymerization temperature of 60 ° C. for 10 hours. The polymerization reactant was precipitated in excess methanol, and then filtered and dried to synthesize P (HOPMI / THP-OPMI / CyPMI / AMMA / MMA). The yield of obtained P (HOPMI / THP-OPMI / CyPMI / AMMA / MMA) was 87%, and the film shape was easy about 40,500 as a weight average molecular weight as a result of molecular weight measurement by GPC.

Example  8. Organic Antireflection film  Preparation and Application of the Composition

The copolymers obtained in Examples 4 to 7 were dissolved in a weight ratio of about 1:20 to 1:50 with respect to propylene glycol monomethyl ether acetate solvent having excellent film forming ability, and then various additives such as a thermal crosslinking agent and a stabilizer were added. After stirring, the solution was filtered through a microporous membrane filter to prepare an organic antireflection coating solution for short wavelength far ultraviolet exposure. This is spin coated onto a silicon wafer and crosslinked at 100 ° C. to 250 ° C. for 10 to 120 seconds to prevent intermixing with the photoresist. Thereafter, commercial photoresist was spin-coated on the anti-reflection film in a general process sequence to perform an optical microcircuit processing process. The organic anti-reflective coating composition using the copolymer obtained from the examples formed an acid equilibrium with the photoresist during the development after the exposure process, so that no undercutting or footing was formed at the bottom of the photoresist micropattern, Due to the small size of the microcircuit of the pattern is also very small, it is easy to form a high-resolution microcircuit of 70nm ~ 150nm class.

As described above, the organic anti-reflection film using the polymer having a copolymer as a base structure according to the present invention is a gas generated even when high temperature thermal crosslinking is performed by introducing a new thermally crosslinkable cyanaito crosslinking group into the polymer chain as a covalent bond. It has almost no thermal stability, excellent adhesion to the substrate, and sufficient absorbance to have as an organic anti-reflective film.It suppresses reflections in the lower layer during the exposure process and prevents standing waves due to changes in the thickness of the light source and photoresist used. It can be removed, and the high etching ability to the plasma ensures stable circuit transfer to the substrate. Therefore, when the polymer according to the present invention is used as an organic anti-reflection film in an exposure process using an excimer laser having an exposure wavelength of 248 nm, 193 nm, and 157 nm in semiconductor manufacturing, the memory element of 1 gigabit DRAM or more or a system integrated circuit of 70 nm to 150 nm unit is fine. Since the circuit fabrication can be performed stably, the production yield of semiconductor devices can be increased.

Claims (7)

N-cyanatophenylmaleimide-containing copolymer represented by the following formula (1). [Formula 1]

Wherein R is H, tetrahydropyranyl, -COOR 5, -Si (R 6) ₃ or a t-butyl group, where R 5 and R 6 are each a methyl group, a t-butyl group or an alkyl group having 2 to 3 carbon atoms, R1 and R3 are each hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxyalkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group or halogenated alkyl group having 1 to 6 carbon atoms, R2 and R4 are each hydrogen or a methyl group, The ratio of each monomer is based on the total mole fraction k + l + m + n of the monomer, the mole fraction of k is 0 to 0.3, the mole fraction of l is 0 to 0.7, the mole fraction of m is 0.1 to 0.5, and the mole fraction of n is 0.1 to 0.4, where the mole fraction of k may be two N-phenylmaleimide monomers represented by k. The N-cyanatophenylmaleimide-containing copolymer according to claim 1, wherein the copolymer has a weight average molecular weight of 10,000 to 100,000. In the method for producing a copolymer containing the polymerized unit represented by the following formula (1) in the main chain, a polymerization solvent is selected from the group consisting of dioxane, tetrahydrofuran, methyl ethyl ketone or an aromatic solvent, and azo as a polymerization initiator. N-cyanae using one or more selected from the group consisting of bisisobutyronitrile (AIBN), di-t-butyloxide (DTBP), benzoyl peroxide (BPO) or azobisvaleronitrile (AIVN) A process for producing a tophenylmaleimide containing copolymer. [Formula 1]

Wherein R is H, tetrahydropyranyl, -COOR 5, -Si (R 6) ₃ or a t-butyl group, where R 5 and R 6 are each a methyl group, a t-butyl group or an alkyl group having 2 to 3 carbon atoms, R1 and R3 are each hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxyalkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group or halogenated alkyl group having 1 to 6 carbon atoms, R2 and R4 are each hydrogen or a methyl group, The ratio of each monomer is based on the total mole fraction k + l + m + n of the monomer, the mole fraction of k is 0 to 0.3, the mole fraction of l is 0 to 0.7, the mole fraction of m is 0.1 to 0.5, and the mole fraction of n is 0.1 to 0.4, where the mole fraction of k may be two N-phenylmaleimide monomers represented by k. An organic antireflective coating composition for a semiconductor manufacturing process comprising a polymer, an organic solvent, and at least one additive represented by the following Chemical Formula 1. [Formula 1]

Wherein R is H, tetrahydropyranyl, -COOR 5, -Si (R 6) ₃ or a t-butyl group, where R 5 and R 6 are each a methyl group, a t-butyl group or an alkyl group having 2 to 3 carbon atoms, R1 and R3 are each hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxyalkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group or halogenated alkyl group having 1 to 6 carbon atoms, R2 and R4 are each hydrogen or a methyl group, The ratio of each monomer is based on the total mole fraction k + l + m + n of the monomer, the mole fraction of k is 0 to 0.3, the mole fraction of l is 0 to 0.7, the mole fraction of m is 0.1 to 0.5, and the mole fraction of n is 0.1 to 0.4, where the mole fraction of k may be two N-phenylmaleimide monomers represented by k. The method of claim 4, wherein 0.2 to 20% by weight of the polymer represented by Chemical Formula 1 is dissolved in an organic solvent, and 0.1 to 10% by weight of one or more additives are respectively mixed with the organic solvent. Antireflective coating composition. The method of claim 4, wherein the organic solvent is butyrolactone, cyclopentanone, cyclohexanone, dimethyl acetamide, dimethyl formamide, dimethyl sulfoxide, N -methyl pyrrolidone, propylene glycol monomethyl ether, propylene glycol mono A composition for forming an organic antireflection film for a semiconductor manufacturing process selected from the group consisting of methyl ether acetate, ethyl lactate and mixtures thereof. An organic antireflection film formed by any one of claims 4 to 6.