KR100959190B1 - DEVELOPER-SOLUBLE BOTTOM ANTI-REFLECTIVE COATING COMPOSITION FOR DUVDeep UV LITHOGRAPHY AND PROCESS OF PRODUCING PATTERNED MATERIALS BY USING THE SAME - Google Patents

Abstract

The present invention relates to a bottom antireflection coating composition comprising a compound crosslinked as heat and decrosslinked by an acid generated by light.

The bottom anti-reflective coating composition comprises an aromatic ring-containing polymer comprising a unit structure having strong absorption in a short wavelength region (eg, 157, 193, 248 nm), and is crosslinked as heat and generated by light generated acid. The compound crosslinked by the compound causes crosslinking reaction with the aromatic ring-containing polymer, and has a property of being soluble by the developer in the photolithographic process by being crosslinked by exposure.

Accordingly, the present invention provides a bottom anti-reflective coating which can simplify the process and reduce the thickness of the photoresist film as well as increase the photolithographic process margin by dissolving together with the photoresist in the photoresist development process in the photolithographic process. It can be formed.

Photolithographic, bottom anti-reflective coating (BARC), crosslinking agent, aromatic ring

Description

A near-ultraviolet bottom anti-reflective coating composition soluble in a developer and a method for forming a patterned material using the same {DEVELOPER-SOLUBLE BOTTOM ANTI-REFLECTIVE COATING COMPOSITION FOR DUV (Deep UV) LITHOGRAPHY AND PROCESS OF PRODUCING PATTERNED MATERIALS BY USING THE SAME}

The present invention relates to a novel bottom antireflective composition (BARC) useful for photolithographic processes and methods of forming patterned materials using the same.

As semiconductor devices are highly integrated, the demand for ultra-fine patterns in photolithography processes is increasing day by day. Effective photolithographic techniques are essential to achieving a reduction in shape size. Photolithographic influences the fabrication of microscopic structures in terms of directly imaging a pattern on a given substrate, as well as in manufacturing a mask typically used for such imaging.

Typical photolithographic processes involve forming a patterned resist layer by patterning exposing the radiation-sensitive resist to imaging radiation. Currently, there are two types of anti-reflective coating (BARC) in the lower layer of photoresist. Used. Inorganic anti-reflective coating (BARC) has a good matching degree to the lower step, but it is not easy to remove during the subsequent etching process, requires a chemical vapor deposition process, and has a disadvantage that a lot of pattern lifting occurs recently, (BARC) is preferred. However, the organic anti-reflection film BARC may also cause reflection notching, standing wave, and distortion of the photoresist pattern when a film having high reflectance is formed on the substrate or when a step occurs. Therefore, by using a material that absorbs the wavelength band of the light source used at the time of exposure well, the anti-reflection film (BARC) that optimized the anti-reflection was introduced. In addition, it can be introduced onto a substrate by the method of spin coating, which simplifies the process and gradually increases its use.

In the photolithographic process using the organic antireflection film (BARC), the organic antireflection film is applied to the object to be etched (for example, a silicon wafer, an insulating film or a conductive film) for final etching by spin coating, followed by baking at a high temperature. It is introduced through. Subsequently, the photoresist is applied on the organic antireflection film BARC by the same spin coating method, followed by baking. In the next step, the photoresist film is exposed using a photomask, followed by a soft baking method, followed by a developing step to complete a desired pattern. Thereafter, the anti-reflective coating (BARC) is etched using the generated photoresist pattern as a mask. The anti-reflection film BARC is used as a mask to etch the final etching target (for example, a silicon wafer, an insulating film, or a conductive film).

The etching of the anti-reflection film BARC in such a series of processes requires high etching resistance and a thick film quality of the photoresist film serving as a mask. If there is no characteristic of the photoresist film, after the anti-reflection film (BARC) etching process, there is a disadvantage that a distorted pattern different from the conventional photoresist pattern is obtained. In addition, as the film quality of the photoresist increases, another shortcoming of the photo pattern is significantly reduced in the short wavelength region of 248 nm, 193 nm, and 154 nm. In order to compensate for these disadvantages and reduce the steps of the process, development of anti-reflection film (BARC) that can be dissolved in the photoresist developer when the photoresist is developed after exposure and soft baking has been in progress.

In the prior art, although there are anti-reflective film (BARC) materials that can be dissolved in many photoresist developer solutions, it is extremely difficult to overcome the various limitations that appear due to their simple dissolving properties, e.g. Isotropic etching or narrow baking temperature margins, which dissolve to the bottom of the photoresist and eventually lead to collapse of the photoresist, have inevitably limited compatibility with the photoresist. Accordingly, there is a continuing need for anti-reflective coating (BARC) compositions that have been made up for in the prior art.

SUMMARY OF THE INVENTION The present invention is directed to solving and improving the problems of the prior art as described above, which is used to perform photolithographic techniques using antireflective compositions that are soluble in a photoresist developer and minimize reflectivity between the photoresist and back layer. It is an object of the present invention to provide a novel bottom anti-reflective coating (BARC) composition.

Another object of the present invention is to provide a method of patterning a backing material layer on a substrate using the BARC composition of the present invention.

According to the present invention (a) an aromatic ring containing polymer represented by the formula (1); (b) a compound represented by the following formula (3); And (c) there is provided a bottom anti-reflective film (BARC) composition comprising an organic solvent.

[Formula 1]

Wherein n is in the range of ₁ ≦ n <190, R ₁ is any one of structures represented by the following general formula (2), R ₂ , R ₄ and R ₅ are hydrogen or a methyl group, and R ₃ Is a -H, -CH ₃ , -C ₂ H ₅ or -C (CH ₃ ) ₃ group. In addition, the ratio of a, b, and c is 5 to 20%: 0 to 20%: 60 to 95%.)

[Formula 2]

(Wherein R _ai is -H, -OH, -OCOCH ₃ , -COOH, -CH ₂ OH, a substituted or unsubstituted straight or branched chain alkyl group having 1 to 5 carbon atoms or an alkoxy alkyl group.)

(3)

(Wherein, Q ⁻ is an anion and includes any of Formula 4 below.)

[Formula 4]

The present invention provides a method of forming a patterned material using the bottom anti-reflective coating composition.

The bottom antireflection film composition according to the present invention has a photolithographic technique by having a refractive index and absorbance in a useful range as a bottom antireflection film in a DUV (Deep UV) region such as an ArF (193 nm) and KrF (248 nm) wavelength region when forming a film. When performing, it is possible to minimize the reflectivity between the resist and the back layer, and dissolved in the photoresist developer can be effectively and conveniently removed without a separate etching process in the photoresist development step. In addition, it is possible to provide a photolithographic structure having excellent pattern evaluation results in profile or margin.

Hereinafter, the present invention will be described in more detail.

The present invention provides a bottom anti-reflection film (BARC) composition comprising a compound represented by the following formula (3).

(3)

(Wherein, Q ⁻ is an anion and includes any of Formula 4 below.)

[Formula 4]

In the compound represented by Formula 3, crosslinking reaction occurs between the aromatic ring-containing polymers of the present invention when heat is supplied as in Scheme 1 below, wherein H ⁺ generated from the carboxy group of the polymer is bonded to an anion (Q ⁻ ). After the exposure, it is detached and is characterized by causing a decrosslinking reaction.

Scheme 1

Therefore, the compound represented by Chemical Formula 3 may simultaneously play a role of a crosslinking agent and a photoinitiator for decrosslinking in the bottom antireflection film composition of the present invention.

In addition, an acid may be generated during exposure from a photo acid generator (PAG) included in the photoresist layer on the bottom anti-reflective coating of the present invention to promote the decrosslinking reaction.

The bottom anti-reflective coating composition of the present invention is characterized by comprising a compound represented by the formula (3).

Specifically, the present invention (a) an aromatic ring containing polymer represented by the following formula (1); (b) a compound represented by the following formula (3); And (c) an organic solvent, the bottom anti-reflective coating composition comprising:

[Formula 1]

(In the above formula, 1≤n <190, R ₁ is any one of structures represented by the following formula (2), R ₂ , R ₄ and R ₅ is hydrogen or a methyl group, R ₃ Is a -H, -CH ₃ , -C ₂ H ₅ or -C (CH ₃ ) ₃ group. In addition, the ratio of a, b, and c is 5 to 20%: 0 to 20%: 60 to 95%.)

[Formula 2]

(Wherein R _ai is -H, -OH, -OCOCH ₃ , -COOH, -CH ₂ OH, a substituted or unsubstituted straight or branched chain alkyl group having 1 to 5 carbon atoms or an alkoxy alkyl group.)

(3)

(Wherein, Q ⁻ is an anion and includes any of Formula 4 below.)

[Formula 4]

The aromatic ring-containing polymer (a) includes an aromatic ring represented by Formula 2 having strong absorption in a short wavelength region (for example, 157 nm, 193 nm, 248 nm, etc.), and crosslinking with a crosslinking agent. It characterized in that it comprises a reactor for generating. The crosslinking reactor is a carboxylic acid group in the aromatic ring-containing polymer represented by the formula (1).

The compound represented by Formula 3 (b) may crosslink the repeating unit of the polymer by heat generated during hard baking after the bottom anti-reflective coating is formed, wherein H ⁺ generated from the carboxy group of the polymer is an anion (Q ⁻ ) and When the bond is formed, the photoresist layer is detached by the scanned light source to cause a decrosslinking reaction.

Accordingly, the hard mask composition of the present invention is cured by (a) crosslinking reaction of the compound represented by Formula 3, which acts as a crosslinking agent with the carboxylic acid group of the aromatic ring-containing polymer, and as a photoinitiator upon exposure of the photoresist layer. It becomes a state which can be melt | dissolved easily in a developing solution by the decrosslinking reaction of the compound represented by the said General formula (3) which functions. Thus, the bottom antireflective hardmask layer formed from the hardmask composition of the present invention can be detached with the photoresist layer upon exposure and development of the photoresist.

According to the above, it is the content of c in the aromatic ring-containing polymer represented by the formula (1) to determine the degree of cure of the hard mask composition of the present invention.

In addition, the hard mask composition of the present invention has a solution and film-forming properties which help to form a layer by spin-coating.

The aromatic ring-containing polymer included in the hard mask composition of the present invention is preferably about 1,000 to 30,000 based on the weight average molecular weight.

In the hard mask composition of the present invention, the (a) aromatic ring-containing polymer is preferably used in an amount of 1 to 30 parts by weight based on 100 parts by weight of the (c) organic solvent. When the aromatic ring-containing polymer is used in less than 1 part by weight or in excess of 30 parts by weight, it is difficult to achieve an accurate coating thickness because it becomes less than or exceeds the desired coating thickness.

The hard mask composition of the present invention comprises (a) 1 to 20% by weight of an aromatic ring-containing polymer; (b) 0.1 to 5% by weight of the compound represented by Formula 3; And (c) a composition ratio of 75 to 98.8 wt% of the organic solvent.

When the compound represented by Formula 3 is less than 0.1% by weight, the crosslinking property may not appear, and when the compound represented by Formula 3 is more than 5% by weight, the optical properties of the coating film may be changed by excessive injection.

The organic solvent (c) included in the composition of the present invention is not particularly limited as long as it is an organic solvent having sufficient solubility in the (a) aromatic ring-containing polymer. For example, propylene glycol monomethyl ether acetate (PGMEA), Cyclohexanone, ethyl lactate, and the like. When the organic solvent is less than 75% by weight or more than 98.8% by weight, it becomes less than or exceeds the desired coating thickness, making it difficult to attain an accurate coating thickness.

In addition, the bottom antireflection film (BARC) composition of the present invention may further comprise a crosslinking agent, a crosslinking catalyst or a mixture thereof.

In addition, the bottom anti-reflection film (BARC) composition of the present invention may further comprise an additive such as a surfactant.

In addition, other radiation-sensitive acid catalysts known in the photoresist art may be used as long as they are compatible with the other components of the antireflective composition.

Meanwhile, the present invention includes a method of patterning a backing material layer on a substrate using the antireflective film (BARC) composition.

Specifically, the method of forming the patterned material shape on the substrate,

(a) providing a layer of material on the substrate;

(b) forming a layer of antireflection film (BARC) using the composition of the present invention over the material layer;

(c) forming a radiation-sensitive imaging layer (eg, photoresist layer) over the antireflective (BARC) layer;

(d) generating a pattern of radiation-exposed areas within the radiation-sensitive imaging layer by patternwise exposing the radiation-sensitive imaging layer to radiation;

(e) selectively removing the radiation-sensitive imaging layer and the bottom antireflective film (BARC) layer simultaneously with a developer to expose a portion of the material layer; And

(f) etching the exposed portion of the material layer.

After the step (a) and before the step (b) may further comprise the step of forming a hard mask layer made of an organic material, after forming a hard mask layer made of an organic material before the step (b) of the silicon-containing composition It may further comprise forming a hard mask layer.

The method of forming the patterned material shape on the substrate according to the present invention may be specifically performed as follows. First, a material to be patterned, such as aluminum and SiN (silicon nitride), is formed on a silicon substrate according to a conventional method. The material to be patterned used in the hardmask composition of the present invention can be any conductive, semiconducting, magnetic or insulating material. Subsequently, a bottom anti-reflective coating (BARC) layer is formed by spin-coating to a thickness of 500 kPa to 4000 kPa using the bottom anti-reflective coating composition of the present invention, and cured by baking at 100 ° C. to 300 ° C. for 10 seconds to 10 minutes. When the anti-reflection film (BARC) layer is formed, a radiation-sensitive imaging layer is formed, and an area for forming a pattern is exposed by an exposure process through the imaging layer, and then a development process is performed.

At this time, the imaging layer and the anti-reflection film (BARC) layer is selectively removed to expose a portion of the material layer, and generally dry etching is performed using a CHF ₃ / CF ₄ mixed gas or the like. After the patterned material shape is formed, any remaining resist can be removed by conventional photoresist strippers. By this method, a semiconductor integrated circuit device can be provided.

In the case where the hard mask layer of the organic-containing and / or silicon-containing composition is further formed on the material layer, the pattern can be formed by performing etching in a multi-step manner by changing the etching gas.

The compositions and formed lithographic structures of the present invention can be used in the manufacture and design of integrated circuit devices. For example, it can be used to form patterned material layer structures, such as metal wiring, holes for contacts or bias, insulating sections (e.g., damascene trenches or shallow trench isolations), trenches for capacitor structures, and the like. Can be. It is also to be understood that the invention is not limited to any particular lithographic technique or device structure.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are only for the purpose of explanation and are not intended to limit the scope of the present invention.

Synthesis Example 1

(Synthesis of Terpolymer of Antracene Methyl Methacrylic Acid, Methyl Methacrylate and Methacrylic Acid)

A 2,000 ml three-necked flask equipped with a thermometer, a condenser, a mechanical stirrer, and a dropping funnel was prepared and immersed in an oil bath at 55 ° C. Heating and stirring by magnets were performed on a hotplate and the cooling water temperature of the condenser was fixed at 10 ° C. 40 g of anthracene methyl methacrylic acid, 15 g of methyl methacrylate, and 97 g of methacrylic acid were added to the reactor and dissolved in 360 g of tetrahydrofuran (THF). Then 0.25 g of the reaction initiator, V-60, was added. The reaction was carried out for 10 hours while maintaining the temperature of 55 ° C.

The polymerization was carried out by the above method and the reaction completion time was determined by measuring the molecular weight at regular intervals. At this time, the sample for measuring the molecular weight was prepared by taking 1 g of the reactant, quenching to room temperature, then diluting 0.02 g of the solution to 4% by weight of solids using THF as a solvent. After confirming the desired molecular weight, the reaction was slowly cooled to room temperature.

After the reaction was caught by precipitation in a diethyl ether solvent, the precipitate was filtered and dried.

The molecular weight and polydispersity of the obtained copolymer were measured by GPC under tetrahydrofuran and found to have a molecular weight of 12,000 and a dispersion of 2.3.

[Chemical Formula 5]

Synthesis Example 2

(Synthesis of 4-hydroxynaphthyl methylmethacrylic acid, methylmethacrylate and methacrylic acid terpolymer)

A copolymer was synthesized in the same manner as in Synthesis Example 1, except that 38 g of 4-hydroxynaphthyl methylmethacrylic acid was added to the reactor instead of 40 g of anthracene methylmethacrylic acid.

The molecular weight and polydispersity of the obtained copolymer were measured by GPC under tetrahydrofuran and found to have a molecular weight of 15,000 and a dispersion of 2.6.

[Formula 6]

Synthesis Example 3

(Synthesis of 4-hydroxynaphthyl methylmethacrylic acid, t-butyl methacrylate and methacrylic acid terpolymer)

The copolymer was prepared in the same manner as in Synthesis Example 1, except that 18 g of 4-hydroxynaphthyl methylmethacrylic acid and 22 g of t-butyl methacrylate were added to the reactor instead of 40 g of anthracene methylmethacrylic acid and 15 g of methylmethacrylate. Synthesized.

The molecular weight and polydispersity of the obtained copolymer were measured by GPC under tetrahydrofuran and found to have a molecular weight of 11,000 and a dispersion of 2.4.

[Formula 7]

[Examples 1, 2 and 3]

2.7 g each of the polymers prepared in Synthesis Examples 1, 2 and 3 are crosslinking agents represented by the following Chemical Formula 8, and 0.05 g of a photoinitiator is dissolved in 7.15 g of propylene glycol monomethyl etheracetate (hereinafter referred to as PGMEA) and filtered. To prepare Examples 1, 2 and 3 sample solutions, respectively.

[Formula 8]

The sample solutions prepared in Examples 1, 2, and 3 were each coated with a silicon wafer by spin-coating, and baked at 240 ° C. for 60 seconds to form a film having a thickness of 1000 mm 3.

Refractive index n and extinction coefficient k of the formed films were obtained, respectively. The instrument used was Ellipsometer (J. A. Woollam) and the measurement results are shown in Table 1 below.

As a result of the evaluation, it was confirmed that there are refractive indexes and absorbances that can be used as antireflection films at ArF (193 nm) and KrF (248 nm) wavelengths.

EXAMPLE 4, 5, and 6

The sample solutions prepared in Examples 1, 2 and 3 were respectively coated by spin-coating on aluminum-coated silicon wafers and baked at 240 ° C. for 60 seconds to form a film having a thickness of 1000 mm 3.

Each film formed was coated with KrF photoresist, baked at 110 ° C. for 60 seconds, and exposed to light using an ASML (XT: 1400, NA 0.93) exposure apparatus, and then developed with TMAH (2.38 wt% aqueous solution). In addition, the FE-SEM was used to examine the line and space patterns of 90 nm, respectively. The same results as in FIGS. 1A to 1C were obtained. In addition, the exposure latitude (EL) margin according to the change of the exposure amount and the depth of focus (DoF) margin according to the distance change between the light source are shown in Table 2 below.

As a result of pattern evaluation, good results were found in terms of pattern profile and margin.

In addition, the cross-sections of each of the patterned specimens were examined by FE-SEM. As shown in Figures 2a to 2c it was confirmed that the anti-reflection film (BARC) layer formed from the hard mask composition of the present invention during the photoresist development process was dissolved in the developer and removed.

1A-1C are FE-SEM photographs of a 90 nm line and space pattern plane

Figures 2a to 2c are cross-sectional views of 90nm line and space pattern

FE-SEM photo

Claims (9)

delete (a) an aromatic ring-containing polymer represented by Formula 1 below; (b) a compound represented by any one of the following Formula 3; And (c) A bottom anti-reflective coating composition comprising an organic solvent. [Formula 1]

(Wherein ₁ ≦ n <190, R ₁ is any one of structures represented by the following Formula 2, R ₂ , R ₄ and R ₅ are hydrogen or a methyl group, and R ₃ is —H, —CH ₃ , -C ₂ H ₅ or -C (CH ₃ ) ₃ group, the ratio of a, b, c is 5-20%: 0-20%: 60-95%.) [Formula 2]

(Wherein R _ai is -H, -OH, -OCOCH ₃ , -COOH, -CH ₂ OH, a substituted or unsubstituted straight or branched chain alkyl group having 1 to 5 carbon atoms or an alkoxy alkyl group.) (3)

(Wherein, Q ⁻ is an anion and includes any of Formula 4 below.) [Formula 4]

The method of claim 2, wherein the composition (a) 1 to 20% by weight of an aromatic ring containing polymer; (b) 0.1 to 5% by weight of a compound represented by any one of Formula 3; And (c) 75 ~ 98.8% by weight of organic solvent The bottom anti-reflective coating composition comprising a. The bottom antireflection film composition according to claim 2, wherein the aromatic ring-containing polymer has a weight average molecular weight of 1,000 to 30,000. The bottom antireflection film composition according to claim 2, wherein the composition further comprises a crosslinking agent, a crosslinking catalyst or a mixture thereof. The bottom anti-reflection film composition according to claim 2, wherein the composition further comprises a surfactant. (a) providing a layer of material on the substrate; (b) forming a bottom antireflective film (BARC) layer using the composition according to any one of claims 2 to 6 above the material layer; (c) forming a radiation-sensitive imaging layer over the bottom antireflection film (BARC) layer; (d) generating a pattern of radiation-exposed areas within the radiation-sensitive imaging layer by patternwise exposing the radiation-sensitive imaging layer to radiation; (e) selectively removing the radiation-sensitive imaging layer and the bottom antireflective film (BARC) layer simultaneously with a developer to expose a portion of the material layer; And (f) forming a patterned material shape by etching the exposed portion of the material layer. The method of claim 7, wherein And forming a hard mask layer made of organic material after step (a) and before step (b). The method of claim 8, And forming a hardmask layer of the silicon-containing composition prior to step (b) after forming the hardmask layer of organic material.

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