CN117075429A

CN117075429A - Underlayer compound for lithography, multilayer structure, and method for manufacturing semiconductor device

Info

Publication number: CN117075429A
Application number: CN202310558252.5A
Authority: CN
Inventors: 李鎭均; 具叡珍; 金佳映
Original assignee: Inha Industry Partnership Institute
Current assignee: Inha Industry Partnership Institute
Priority date: 2022-05-17
Filing date: 2023-05-17
Publication date: 2023-11-17

Abstract

Provided are a underlayer compound for lithography, which improves resolution and sensitivity of a photoresist layer, suppresses collapse of a photoresist pattern, and has improved etching resistance, a multilayer structure, and a method of manufacturing a semiconductor device. The underlayer compound for lithography comprises an alternating copolymer comprising a repeating unit represented by formula 1 or an alkylated tin oxide nanocluster having a counter anion: [ 1 ]]In formula 1, R ₁ 、R ₂ 、R ₃ 、R ₄ 、R ₅ Each of a, a and n is the same as described in the specification.

Description

Underlayer compound for lithography, multilayer structure, and method for manufacturing semiconductor device

The present application claims priority from korean patent application No. 10-2022-0060028, filed 5/17/2022, and korean patent application No. 10-2023-0026138, filed 2/27/2023, which are incorporated herein by reference in their entireties.

Technical Field

The present disclosure relates to a underlayer compound for lithography used in semiconductor device manufacturing, a multilayer structure formed using the underlayer compound for lithography, and a method for manufacturing a semiconductor device using the underlayer compound for lithography.

Background

Photolithography may include an exposure process and a development process. The exposure process may include exposing the resist layer to light of a particular wavelength to cause a change in the chemical structure of the resist layer. The development process may include selectively removing the exposed portions or the unexposed portions of the resist layer by utilizing a solubility difference between the exposed portions and the unexposed portions.

Recently, as semiconductor devices are highly integrated and downsized, line widths of patterns in the semiconductor devices are downsized. In order to form the minute pattern, various studies have been made to improve resolution and sensitivity of a resist pattern formed by photolithography and to suppress collapse (collapse) of the resist pattern.

Disclosure of Invention

The present disclosure solves the task of providing a underlayer compound that can improve resolution and sensitivity of a photoresist layer, suppress collapse of a photoresist pattern, and have improved etch resistance, a multilayer structure formed using the underlayer compound, and a method for manufacturing a semiconductor device using the underlayer compound.

The tasks addressed by the present disclosure are not limited to the above tasks, and other tasks not mentioned can be clearly understood by those skilled in the art from the following description.

According to the inventive concept, a underlayer compound for lithography includes an alternating copolymer including a repeating unit represented by formula 1 or an alkylated tin oxide nanocluster having a counter anion.

[ 1]

In formula 1, R ₁ Alkyl of 1 to 18 carbon atoms, R ₂ 、R ₃ 、R ₄ And R is ₅ Each independently is hydrogen, deuterium, or an alkyl group of 1 to 3 carbon atoms, a is iodine or tin with an alkyl group, and "n" is an integer of 2 to 10000.

The alkylated tin oxide nanoclusters include a core structure including tin oxide and an alkyl group of 1 to 18 carbon atoms bonded to the tin atoms of the core structure and the counter anion is an alkylbenzenesulfonate anion.

According to the inventive concept, a multilayer structure comprises: a lower layer; a cushion layer positioned on the lower layer; and a photoresist layer on the pad layer. The underlayer comprises an alternating copolymer comprising repeating units represented by formula 1 or alkylated tin oxide nanoclusters having a counter anion.

According to the inventive concept, a method for manufacturing a semiconductor device includes: forming a cushion layer on the lower layer; and forming a photoresist layer on the pad layer. The step of forming the underlayer comprises applying an underlayer compound onto the underlayer, the underlayer compound comprising an alternating copolymer comprising a repeating unit represented by formula 1 or an alkylated tin oxide nanocluster having a counter anion.

Drawings

The accompanying drawings are included to provide a further understanding of the inventive concepts, and are incorporated in and constitute a part of this specification. The drawings illustrate example embodiments of the inventive concepts and, together with the description, serve to explain the principles of the inventive concepts. In the drawings:

FIG. 1 is a schematic view showing a maleimide substituted with an alkyl chain (R) prepared according to synthetic example 1 _H MI 8) of the nuclear magnetic resonance spectrum;

FIG. 2A is a graph showing the result of nuclear magnetic resonance spectroscopy of styrene (ISt) having iodine introduced prepared according to synthetic example 2-1;

FIG. 2B is a graph showing the nuclear magnetic resonance spectrum results of tin-incorporated styrene (SnSt) prepared according to synthetic example 2-2;

fig. 3 shows images of negative resist patterns formed by an euv lithography process according to experimental examples 1-1, experimental examples 1-2 and experimental examples 1-3;

fig. 4 shows graphs showing evaluation results of the solubility of the resist films according to experimental examples 1-1, experimental examples 1-2, and experimental examples 1-3;

fig. 5 shows an image of a negative resist pattern formed by an extreme ultraviolet lithography process according to experimental example 2;

fig. 6 shows a graph showing the evaluation result of the solubility of the resist film according to experimental example 2;

Fig. 7 shows a graph showing the evaluation result of the dimensional change of the resist pattern according to experimental example 2; and

fig. 8 to 11 are cross-sectional views illustrating a method for manufacturing a semiconductor device according to an embodiment of the inventive concept.

Detailed Description

In order to fully understand the construction and effect of the inventive concept, preferred embodiments of the inventive concept will be explained with reference to the accompanying drawings. However, the inventive concept may be embodied in various forms, with various modifications, and should not be construed as being limited to the embodiments set forth herein. The embodiments are provided so that the disclosure of the inventive concept is complete by an explanation of the embodiments and fully informs a person of ordinary skill in the art to which the inventive concept pertains of the scope of the inventive concept.

The terminology used herein is for the purpose of describing example embodiments only and is not intended to be limiting of the inventive concepts. In the disclosure, singular is also intended to include plural unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated elements, but do not preclude the presence or addition of one or more other elements.

In the present description, unless otherwise indicated, alkyl includes straight, branched or cyclic monovalent saturated hydrocarbon groups.

In the description, fluoroalkyl is an alkyl in which at least one hydrogen is replaced by fluorine.

In the description, unless otherwise defined, the case where a chemical bond is not drawn at a position where the chemical bond is required may mean that a hydrogen atom is bonded.

Hereinafter, embodiments of the inventive concept will be explained in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used for the same constituent elements, and repeated explanation thereof will be omitted.

An under layer (underlayer) compound according to an embodiment of the inventive concept will be explained.

The underlayer compound according to an embodiment of the inventive concept may be used in the manufacture of semiconductor devices and may be used in a photolithography process for the manufacture of semiconductor devices. The underlayer compound may be used in, for example, an extreme ultraviolet lithography process or an electron beam lithography process. Extreme ultraviolet may mean ultraviolet having a wavelength of about 10nm to about 124nm, in particular, ultraviolet having a wavelength of about 13.0nm to about 13.9nm, and more in particular, ultraviolet having a wavelength of about 13.4nm to about 13.6 nm.

According to some embodiments, the cushion compound may include an alternating copolymer comprising the repeating unit represented by formula 1.

[ 1]

In formula 1, R ₁ Alkyl of 1 to 18 carbon atoms, R ₂ 、R ₃ 、R ₄ And R is ₅ Each independently is hydrogen, deuterium, or an alkyl group of 1 to 3 carbon atoms, a is hydrogen, iodine, or tin with an alkyl group, and "n" is an integer of 2 to 10000.

Tin having an alkyl group may be a functional group represented by formula 2.

[ 2]

In formula 2, R ₆ 、R ₇ And R is ₈ Each independently is an alkyl group of 1 to 18 carbon atoms and is a moiety bonded to a carbon of formula 1.

The cushion compound may include an alternating copolymer including a repeating unit represented by formula 3.

[ 3]

In formula 3, R ₁ Alkyl of 1 to 18 carbon atoms, a is hydrogen, iodine or tin with alkyl groups, and "n" is an integer of 2 to 10000.

In formula 3, a may be a functional group represented by formula 2.

The cushion compound may include, for example, an alternating copolymer comprising repeating units represented by formula 3-1, formula 3-2, or formula 3-3.

[ 3-1]

[ 3-2]

[ 3-3]

In the formula 3-1, the formula 3-2 and the formula 3-3, "n" is an integer of 2 to 10000.

The bedding compound may be synthesized by free radical polymerization of a styrene derivative and a maleimide substituted with an alkyl chain.

Synthesis example 1]Maleimide substituted with alkyl chain (R) _H MI 8) synthesis (reaction 1)

Round bottom flask (250 cm) ³ ) Triphenylphosphine (2.65 g,10.1 mmol) and tetrahydrofuran (THF, 70 cm) were injected into the flask ³ ) And stirred to prepare a solution and the solution was cooled to about-78 ℃ in a cooling bath. To the cooled solution was injected 1-octanol (1.45 g,11.10 mmol) to prepare a reaction mixture, and the reaction mixture was stirred for about 1 hour. Diisopropyl azodicarboxylate (DIAD, 2.04g,10.1 mmol) was injected into the reaction mixture, and the reaction mixture was stirred for about 5 minutes. Neopentyl alcohol (0.489 g,5.55 mmol) and maleimide (1.00 g,10.1 mmol) were added to the reaction mixture to prepare a reaction product, and the reaction product was stirred in a cooling bath at about-78 ℃ for about 10 minutes. The cooling bath was removed and the reaction product was stirred at room temperature (r.t.) for about 12 hours. After the completion of the reaction, the reaction product was concentrated under reduced pressure to obtain a product. The product was purified by column chromatography (using silica gel and dichloromethane). Thereafter, the product was recrystallized (using isopropanol: hexane=1:2 as solvent) to finally synthesize 1-octyl-1H-pyrrole-2, 5-dione (R) as a white solid _H MI 8) (1.6 g, 75.7% yield). ¹ H NMR(400MHz，CDCl ₃ )：δ＝6.7(s，2H)，3.53(t，J＝8Hz，2H)，1.65-1.58(m，2H)，1.37-1.19(m，10H)，0.94-0.83(m，3H)。

[ reaction 1]

FIG. 1 is a schematic view showing a maleimide substituted with an alkyl chain (R) prepared according to synthetic example 1 _H MI 8) is provided. Referring to FIG. 1, it was confirmed that 1-octyl-1H-pyrrole-2, 5-dione (R) according to synthetic example 1 _H MI 8) yield.

Synthesis example 2-1 Synthesis of styrene (ISt) having iodine introduced thereto (reaction 2-1)

Round bottom flask (250 cm) ³ ) 3-iodobenzaldehyde (3 g,12.93 mmol), methyltriphenylphosphonium bromide (6.93 g,19.39 mmol) and THF (75 cm) were injected ³ ) To produce a reaction product, and stirring the reaction product in a cooling bath at a temperature of about 0 ℃. After that, it was dissolved in THF (20 cm ³ ) The solution of potassium tert-butoxide (2.18 g,19.39 mmol) was added dropwise to the reaction product and stirred. The cooling bath was removed and the reaction product was stirred at room temperature (r.t.) for about 12 hours. After the completion of the reaction, hexane (100 cm ³ ) The reaction product was injected to prepare a solid product, and the solid product was filtered through celite (celite) to obtain an organic solvent layer. Then, the filtered organic solvent layer was concentrated under reduced pressure to obtain a product. The product was purified by column chromatography (using silica gel and hexane) to finally recover 3-iodostyrene (ISt) (1.7 g, yield 57%) as a pale yellow viscous liquid. ¹ H NMR(400MHz，CDCl ₃ )：δ＝7.79(s，1H)，7.61(d，J＝7.8Hz，1H)，7.38(d，J＝7.7Hz，1H)，7.08(t，J＝7.8Hz，1H)，6.64(dd，J＝6.4Hz、28.4Hz，1H)，5.76(d，J＝17.6Hz，1H)，5.31(d，J＝10.9Hz，1H)。

[ reaction 2-1]

Fig. 2A is a graph showing the nuclear magnetic resonance spectrum result of styrene (ISt) having iodine introduced prepared according to synthetic example 2-1. Referring to fig. 2A, the yield of 3-iodostyrene (ISt) according to synthetic example 2-1 can be confirmed.

Synthesis example 2-2 Synthesis of styrene (SnSt) into which tin was introduced (reaction 2-2)

Round bottom flask (100 cm) ³ ) Magnesium turnings (1.2 g,49.2 mmol) and THF (7 cm) were added ³ ) To prepare a solution. A freeze-pump-thaw (freeze-pump-thaw) process was performed three times to remove oxygen from the solution. The solution was then stirred at about 60 ℃ for about 1 hour, and 4-bromostyrene (5.0 g,27.3 mmol) was added to the solution in a dropwise manner. Will dissolve in THF (30 cm) at 0deg.C ³ ) To this solution was added another solution of trimethyltin chloride (6.5 g,32.8 mmol) to prepare a reaction mixture. The reaction mixture was stirred at room temperature for about 2 hours. After completion of the reaction, water (20 cm) ³ ) And hexane (100 cm) ³ ) Insoluble components were removed by filtration using alumina. The filtrate was washed with water and saturated aqueous sodium chloride solution, and anhydrous MgSO was added to the filtrate ₄ Followed by stirring to remove residual moisture in the filtrate. The filtrate was concentrated to obtain a product, and the product was purified by column chromatography (using silica gel and hexane) to synthesize 4-trimethylstannylstyrene (SnSt) (3.5 g, yield 48%) as a colorless liquid. ¹ H NMR (400 MHz, deuterated acetone): δ=7.45 (dd, j=26 Hz, 7Hz, 4H), 6.73 (dd, j=18 Hz, 11Hz, 1H), 5.81 (d, j=18 Hz, 1H), 5.22 (d, j=11 Hz, 1H), 0.36-0.20 (m, 9H).

[ reaction 2-2]

Fig. 2B is a graph showing the nuclear magnetic resonance spectrum result of tin-incorporated styrene (SnSt) prepared according to synthetic example 2-2. Referring to fig. 2B, the yield of 4-trimethylstannyl styrene (SnSt) according to synthetic example 2-2 can be confirmed.

Synthesis example 3-1]Bedding compound of formula 3-1 (P (R) _H MI 8-St)) synthesis (reaction 3-1)

To Schlenk tube (50 cm) ³ ) R is injected into _H MI8 (1.0 g,4.78 mmol), styrene (available from TCI corporation) (0.5 g,4.78 mmol) and 2,2' -azobis (2-methylpropanenitrile) (AIBN, 0.01g,0.06 mmol) were combined and a nitrogen purge was performed. THF (20 cm) ³ ) Is injected into the tube to prepare a solution, and a freeze-pump-thaw process is performed three times to remove oxygen from the solution. The solution was then stirred at a temperature of about 60 ℃ for about 12 hours. Thereafter, the solution in the tube was added dropwise to hexane (300 cm ³ ) To prepare a precipitate, and filtering the precipitate for recovery. After drying the precipitate, according to the result of Gel Permeation Chromatography (GPC) analysis, a number average molecular weight (M) of 0.64g was obtained _n ) A polymer (P (R) having 15605 and a polydispersity index (PDI) of 1.63 _H MI8-St))。

[ reaction 3-1]

Synthesis example 3-2 ]Cushion compounds of formula 3-2 (P (R) _H MI 8-ISt)) synthesis (reaction 3-2)

To Schlenk tube (25 cm) ³ ) R is injected into _H MI8 (0.5 g,2.39 mmol), 3-iodostyrene ISt (0.55 g,2.39 mmol) and AIBN (0.005 g,0.03 mmol) were combined and a nitrogen purge was performed. THF (6 cm) ³ ) Is injected into the tube to prepare a solution, and a freeze-pump-thaw process is performed three times to remove oxygen from the solution. The solution was then stirred at a temperature of about 60 ℃ for about 12 hours. Thereafter, the solution in the tube was added dropwise to hexane (250 cm ³ ) To prepare a precipitate, and filtering the precipitate for recovery. After drying the precipitate, according to the GPC analysis result, a number average molecular weight (M) of 0.68g was obtained _n ) A polymer (P (R) having 12543 and a polydispersity index (PDI) of 2.10 _H MI8-ISt))。

[ reaction 3-2]

Synthesis examples 3 to 3]Cushion compounds of formula 3-3 (P (R) _H MI 8-SnSt)), synthesis (reaction 3-3)

To Schlenk tube (25 cm) ³ ) R is injected into _H MI8 (0.5 g,2.39 mmol), 4-trimethylstannylstyrene (SnSt, 0.64g,2.39 mmol) and AIBN (0.005 g,0.030 mmol) were combined and a nitrogen purge was performed. THF (10 cm) ³ ) Is injected into the tube to prepare a solution, and a freeze-pump-thaw process is performed three times to remove oxygen from the solution. The solution was then stirred at a temperature of about 60 ℃ for about 12 hours. Thereafter, the solution in the tube was added dropwise to methanol (250 cm ³ ) To prepare a precipitate, and filtering the precipitate for recovery. After drying the precipitate, according to the GPC analysis result, a number average molecular weight (M) of 0.68g was obtained _n ) Polymer (P (R) having 15551 and a polydispersity index (PDI) of 2.12 _H MI8-SnSt))。

[ reaction 3-3]

Table 1 shows the molecular weights of the bedding compounds synthesized according to synthesis examples 3-1 to 3-3.

TABLE 1

Experimental example 1-1]Is coated with a cushion compound of formula 3-1 (P (R _H MI 8-St)) of the solubility of the resist film formed on the substrate

P (R) to be dissolved in Propylene Glycol Monomethyl Ether Acetate (PGMEA) _H A solution of MI8-St (1.0 wt/vol%) was applied to a silicon substrate by spin coating at about 1500rpm for about 60 seconds and at about 110℃Heated for about 1 minute to form a blanket (thickness of about 23 nm). In the presence of a coating of P (R _H MI 8-St) as a cushion layer, P (R) dissolved in PF-7600 (3M company) was applied by spin coating at about 1500rpm for about 60 seconds on a silicon substrate _F MI 6-St) solution (1.2 wt/vol%, korean patent application No. 10-2017-0085451/Korean patent registration No. 10-1901522), and heated at about 110℃for about 1 minute to form a resist film (thickness of about 25nm, total thickness of stacked films of about 48 nm). Then, at about 3mJ/cm ² To about 60mJ/cm ² The resist pattern (circular) was formed by irradiating the emitter ultraviolet rays with a dose in the range of (a) and performing a developing process using PF-7600 for about 30 seconds. The thickness of the resist pattern remaining on the silicon substrate was measured according to the dose, and the change in the solubility of the resist film was evaluated.

Experimental examples 1-2]Is coated with a cushion compound of formula 3-2 (P (R _H MI 8-ISt)) of the solubility of a resist film formed on a substrate

P (R) to be dissolved in Propylene Glycol Monomethyl Ether Acetate (PGMEA) _H The solution (1.0 wt/vol%) of MI8-ISt was applied to a silicon substrate by spin coating at about 1500rpm for about 60 seconds and heated at about 110℃for about 1 minute to form a blanket (thickness about 23 nm). In the presence of a coating of P (R _H MI 8-ISt) as a cushion layer, P (R) dissolved in PF-7600 (3M company) was applied by spin coating at about 1500rpm for about 60 seconds on a silicon substrate _F MI 6-St) solution (1.2 wt/vol%, korean patent application No. 10-2017-0085451/Korean patent registration No. 10-1901522), and heated at about 110℃for about 1 minute to form a resist film (thickness of about 25nm, total thickness of stacked films of about 48 nm). Then, at about 3mJ/cm ² To about 60mJ/cm ² The resist pattern (circular) was formed by irradiating the emitter ultraviolet rays with a dose in the range of (a) and performing a developing process using PF-7600 for about 30 seconds. The thickness of the resist pattern remaining on the silicon substrate was measured according to the dose, and the change in the solubility of the resist film was evaluated.

Experimental examples 1 to 3]Is coated with a cushion compound of formula 3-3 (P (R _H Evaluation of solubility of resist film formed on substrate of MI 8-SnSt)

P (R) to be dissolved in Propylene Glycol Monomethyl Ether Acetate (PGMEA) _H A solution of MI8-SnSt (1.0 wt/vol%) was applied to a silicon substrate by spin coating at about 1500rpm for about 60 seconds and heated at about 110℃for about 1 minute to form a blanket (thickness of about 21 nm). In the presence of a coating of P (R _H MI 8-SnSt) as a cushion layer, P (R) dissolved in PF-7600 (3M company) was applied by spin coating at about 1500rpm for about 60 seconds _F MI 6-St) solution (1.2 wt/vol%, korean patent application No. 10-2017-0085451/Korean patent registration No. 10-1901522), and heated at about 110℃for about 1 minute to form a resist film (thickness of about 25nm, total thickness of stacked films of about 46 nm). Then, at about 3mJ/cm ² To about 60mJ/cm ² The resist pattern (circular) was formed by irradiating the emitter ultraviolet rays with a dose in the range of (a) and performing a developing process using PF-7600 for about 30 seconds. The thickness of the resist pattern remaining on the silicon substrate was measured according to the dose, and the change in the solubility of the resist film was evaluated.

In experimental examples 1-1, experimental examples 1-2, and experimental examples 1-3, P (R) for forming a resist film _F MI 6-St) may include an alternating copolymer comprising repeating units represented by formula 4.

[ 4]

Fig. 3 shows images of negative tone (or "negative tone") resist patterns formed by an euv lithography process according to experimental examples 1-1, 1-2, and 1-3.

Referring to fig. 3, according to experimental example 1-1, it was confirmed that the catalyst was prepared by reacting a cushion compound of formula 3-1 (P (R _H MI 8-St)) is applied on a blanket formed on a silicon substrate to form a resist film, and an extreme ultraviolet lithography process is performed on the resist film to form a negative resist pattern (circular shape). Further, according to experimental example 1-2, it was confirmed that the composition was obtained by reacting a cushion compound of formula 3-2 (P (R _H MI8-ISt) applied on a blanket formed on a silicon substrate, and performing an euv lithography process on the resist film, a negative resist pattern (circular shape) is formed. Further, according to experimental examples 1 to 3, it was confirmed that the composition was obtained by reacting a cushion compound of formula 3 to 3 (P (R _H MI 8-SnSt)) is applied on a blanket formed on a silicon substrate to form a resist film, and an extreme ultraviolet lithography process is performed on the resist film to form a negative resist pattern (circular shape).

Fig. 4 shows graphs showing evaluation results of the solubility of the resist films according to experimental examples 1-1, experimental examples 1-2, and experimental examples 1-3.

Referring to fig. 4, a cushion compound (P (R) _H MI 8-St)) when about 6.4mJ/cm ² When the extreme ultraviolet rays of (a) are irradiated on the resist film, the thickness of the resist pattern may be maintained to be about 50% of the thickness of the resist film. On which is coated a cushion compound of formula 3-2 (P (R _H MI 8-ISt)) when about 5.8mJ/cm ² When the extreme ultraviolet rays of (a) are irradiated on the resist film, the thickness of the resist pattern may be maintained to be about 50% of the thickness of the resist film. On which is coated a cushion compound of the formula 3-3 (P (R _H MI 8-SnSt)) at about 5.2mJ/cm ² When the extreme ultraviolet rays of (a) are irradiated on the resist film, the thickness of the resist pattern may be maintained to be about 50% of the thickness of the resist film.

According to some embodiments, the cushion compound may include alkylated tin oxide nanoclusters with a counter anion (or "counter anion"). The alkylated tin oxide nanoclusters may include a core structure including tin oxide and an alkyl group of 1 to 18 carbon atoms bonded to tin elements of the core structure. The core structure may include cations and may form ionic bonds with counter anions. The counter anion may be an alkylbenzenesulfonate anion.

The cushion compound may include or have the structure of formula 5.

[ 5]

In formula 5, R may be an alkyl group of 1 to 18 carbon atoms, rx ^- May be a counter anion and may be an alkylbenzene sulfonate anion. For example, R may be butyl.

Rx ^- May have the structure of formula 6.

[ 6]

In formula 6, R ₉ Alkyl of 1 to 18 carbon atoms. For example, R ₉ May have-CH ₂ (CH ₂ ) ₁₀ CH ₃ Is a structure of (a).

Synthesis example 4 Synthesis of bedding Compound (DS-BTOC) of formula 5 (reaction 4)

At 100cm ³ In a bottle of (C), tetramethyl ammonium hydroxide pentahydrate (5.78 g,31.9 mmol) was dissolved in deionized water (DI water, 64 cm) ³ ) Butyl tin trichloride (3.0 g,10.6 mmol) was rapidly poured into a bottle to prepare a first reaction solution. The first reaction solution was vigorously stirred at room temperature for about 1 hour to obtain a product, and the product was washed several times with DI water and filtered. The product was dried under vacuum to obtain alkylated tin oxide nanoclusters (BTOC, 1.8 g) as a white solid phase. Then, BTOC (1.0 g,0.4 mmol) was dissolved in THF (7 cm) ³ ) To prepare a solution, and injecting a solution dissolved in THF (3 cm) ³ ) Dodecyl benzene sulfonic acid solution to prepare a second reaction solution. The second reaction solution was stirred at about 50 ℃ for about 10 minutes and concentrated. The concentrated material was poured into heptane (100 cm ³ ) To form a precipitate, and filtering the precipitate for recovery. The precipitate was dried under vacuum to obtain DS-BTOC (0.5 g) as a yellow solid phase.

[ reaction 4]

Experimental example 2 evaluation of solubility of resist film formed on substrate coated with underlayer compound (DS-BTOC) of formula 5

1) Comparative example 1: substrate coated with a monomolecular cushion layer (VTMS, vinyltrimethoxysilane)

A solution of VTMS dissolved in PGMEA (20 wt%) was applied to a silicon substrate by spin coating at about 3000rpm for about 30 seconds and heated at about 110 ℃ for about 1 minute to form a first cushion layer. Then, an N-TOC6 solution (1.2 wt/vol%, korean patent application No. 10-2022-007286) dissolved in HFE-7500 (3M Co.) was applied on the silicon substrate coated with the first underlayer by spin coating at about 1500rpm for about 60 seconds, and heated at about 80℃for about 1 minute to form a resist film (thickness about 34 nm). Then, the dosage is about 2mJ/cm ² To about 50mJ/cm ² The exposure process is performed with extreme ultraviolet rays in the range of (a) and the development process is performed for about 40 seconds using HFE-7500 to form a resist pattern (a circular shape). The thickness of the resist pattern remaining on the silicon substrate was measured according to the dose, and the change in the solubility of the resist film was evaluated. Further, the dose required for a resist pattern (circular shape) having a longitudinal diameter of about 180 μm was measured, and the dimensional change of the resist pattern according to the dose was evaluated.

2) Comparative example 2: substrate coated with polymer mat (Korean patent application No. 10-2022-0087787)

A solution (0.8 wt/vol%) of the polymer compound dissolved in PGMEA was applied to the silicon substrate by spin coating at about 2500rpm for about 60 seconds and heated at about 110 ℃ for about 1 minute to form a second underlayer (thickness of about 15 nm). Then, on the silicon substrate coated with the second underlayer, the solution in HFE-7500 (3M Male) was applied by spin coating at about 1500rpm for about 60 secondsSpan), and heated at about 80 c for about 1 minute to form a resist film (thickness of about 34nm, total thickness of stacked films of about 49 nm). Then, at about 2mJ/cm ² To about 50mJ/cm ² The extreme ultraviolet exposure process was performed at a dose within the range of (a) and the development process was performed using HFE-7500 for about 40 seconds to form a resist pattern (a circle). The thickness of the resist pattern remaining on the silicon substrate was measured according to the dose, and the change in the solubility of the resist film was evaluated. Further, the dose required for a resist pattern (circular shape) having a longitudinal diameter of about 180 μm was measured, and the dimensional change of the resist pattern according to the dose was evaluated.

3) Experimental example: substrate coated with a bedding compound of formula 5 (DS-BTOC)

A DS-BTOC solution (1.2 wt/vol%) dissolved in a mixed solvent of n-butyl acetate (nBA) and methyl isobutyl ketone (MIBK) (1:1 by volume) was applied to the silicon substrate by spin coating at about 2000rpm for about 60 seconds and heated at about 80℃for about 1 minute to form a third pad layer (thickness about 25 nm). Then, an N-TOC6 solution (1.2 wt/vol%, korean patent application No. 10-2022-007286) dissolved in HFE-7500 (3M Co.) was applied on the silicon substrate coated with the third underlayer by spin coating at about 1500rpm for about 60 seconds, and heated at about 80℃for about 1 minute to form a resist film (thickness of about 34nm, total thickness of stacked films of about 59 nm). Then, at about 2mJ/cm ² To about 50mJ/cm ² The extreme ultraviolet exposure process was performed at a dose within the range of (a) and the development process was performed using HFE-7500 for about 40 seconds to form a resist pattern (a circle). The thickness of the resist pattern remaining on the silicon substrate was measured according to the dose, and the change in the solubility of the resist film was evaluated. Further, the dose required for a resist pattern (circular shape) having a longitudinal diameter of about 180 μm was measured, and the dimensional change of the resist pattern according to the dose was evaluated.

In experimental example 2, the polymer compound for forming the second underlayer (korean patent application No. 10-2022-0087787) may include a copolymer including a repeating unit represented by formula 7, and the N-TOC6 for forming the resist film (korean patent application No. 10-2022-007286) may include a substance represented by formula 8.

[ 7]

In formula 7, the ratio of (x+y) to z is in the range of about 40:60 to about 60:40, and the ratio of x to y is in the range of about 90:10 to about 30:70.

[ 8]

[(R _F Sn) ₁₂ O ₁₄ (OH) ₆ ] ²⁺ 2[CF ₃ (CF ₂ ) ₂ O(CF ₃ )CFCF ₂ O(CF ₃ )CFCOO ^- ]

In formula 8, R _F Fluoroalkyl of 1 to 18 carbon atoms. For example, R _F May have- (CH) ₂ ) ₂ (CF ₂ ) ₅ CF ₃ Is a structure of (a).

Fig. 5 shows an image of a negative resist pattern formed by an extreme ultraviolet lithography process according to experimental example 2.

Referring to fig. 5, according to comparative example 1, it was confirmed that a negative resist pattern having a circular shape was formed by forming a resist film on a substrate having a first underlayer (VTMS) coated thereon and performing an euv lithography process on the resist film. Further, according to comparative example 2, it was confirmed that a negative resist pattern having a circular shape was formed by forming a resist film on a substrate on which a second underlayer (polymer compound) was coated, and performing an extreme ultraviolet lithography process on the resist film. Further, according to experimental examples, it was confirmed that a negative resist pattern having a circular shape was formed by forming a resist film on a substrate coated with a third underlayer (DS-BTOC) and performing an extreme ultraviolet lithography process on the resist film.

Fig. 6 shows a graph showing the evaluation result of the solubility of the resist film according to experimental example 2.

Referring to FIG. 6, in the case of the substrate having the first cushion layer (VTMS) coated thereon according to comparative example 1, when about 12.1mJ/cm ² When the extreme ultraviolet rays of (a) are irradiated on the resist film, the thickness of the resist pattern may be maintained to be about 50% of the thickness of the resist film. In the case of the substrate according to comparative example 2 having the second cushion layer (polymer compound) coated thereon, when about 11.4mJ/cm ² When the extreme ultraviolet rays of (a) are irradiated on the resist film, the thickness of the resist pattern may be maintained to be about 50% of the thickness of the resist film. In the case of the substrate having the third cushion layer (DS-BTOC) coated thereon according to the experimental example, when about 3.7mJ/cm ² When the extreme ultraviolet rays of (a) are irradiated on the resist film, the thickness of the resist pattern may be maintained to be about 50% of the thickness of the resist film.

Fig. 7 shows a graph showing the evaluation result of the dimensional change of the resist pattern according to experimental example 2.

Referring to FIG. 7, in the case of the substrate having the first cushion layer (VTMS) coated thereon according to comparative example 1, it was confirmed that about 14.7mJ/cm was consumed for forming a resist pattern (circular shape) having a longitudinal diameter of about 180. Mu.m ² Is a dose of (a). In the case of the substrate according to comparative example 2 on which the second cushion layer (polymer compound) was coated, it was confirmed that about 13.4mJ/cm was consumed for forming a resist pattern (circular shape) having a longitudinal diameter of about 180. Mu.m ² Is a dose of (a). In the case of the substrate having the third cushion layer (DS-BTOC) coated thereon according to the experimental example, it was confirmed that about 4.8mJ/cm was consumed for forming a resist pattern (circular) having a longitudinal diameter of about 180 μm ² Is a dose of (a).

A method for manufacturing a semiconductor device using a cushion compound according to an embodiment of the inventive concept will be explained.

Referring to fig. 8, a pad layer 110 may be formed on the lower layer 100, and a photoresist layer 120 may be formed on the pad layer 110. The lower layer 100 may be an etching target layer, and may be formed of any one selected from a semiconductor material, a conductive material, an insulating material, or a combination thereof. The lower layer 100 may be formed as a single layer or may include a plurality of layers stacked.

The underlayer 110 may comprise an underlayer compound comprising an alternating copolymer comprising the repeating unit represented by formula 1, or comprising alkylated tin oxide nanoclusters with a counter anion. The alkylated tin oxide nanoclusters with a counter anion may have the structure of formula 5. The formation of underlayer 110 may include applying underlayer compound to underlayer 100. In an embodiment, the application of the cushion compound may be performed by a spin-coating method.

The photoresist layer 120 may include a resist compound including a fluoroalkyl group. The resist compound may include an alternating copolymer including a repeating unit represented by formula 4, or a substance represented by formula 8. Formation of photoresist layer 120 may include applying a resist compound on underlayer 110 using a fluorine-based solvent. The fluorine-based solvent may include, for example, hydrofluoroether (HFE) and/or Perfluorocarbon (PFC). In an embodiment, the application of the resist compound may include spin coating the resist compound onto the backing layer 110. The formation of the photoresist layer 120 may also include performing heating (e.g., a soft bake process) on the applied resist compound.

Referring to fig. 9, an exposure process may be performed on the photoresist layer 120. The exposure process may include disposing a photomask 130 on the photoresist layer 120 and irradiating light 140 through the photomask 130 onto the photoresist layer 120. The light 140 may be an electron beam or extreme ultraviolet. The photoresist layer 120 may include a first portion 122 exposed to light 140 and a second portion 124 not exposed to light 140. Light 140 may impinge first portion 122 through opening 132 of photomask 130 and light 140 may not impinge second portion 124 due to the blockage of photomask 130.

A portion of underlayer 110 may be under first portion 122 of photoresist layer 120, and light 140 may impinge on the portion of underlayer 110. This portion of underlayer 110 may be referred to as the exposed portion of underlayer 110. Another (remaining) portion of underlayer 110 may be under second portion 124 of photoresist layer 120, and light 140 may be blocked by photomask 130 from impinging on this other (remaining) portion of underlayer 110. This other (remaining) portion of the blanket 110 may be referred to as the unexposed portion of the blanket 110.

The resist compound may also include radicals generated by irradiation of light 140. In an embodiment, the C-F bonds of the fluoroalkyl chains in the resist compound may be broken by secondary electrons generated by the irradiation of light 140 to generate carbon radicals. In the first portion 122 of the photoresist layer 120, the resist compound may include radicals (e.g., carbon radicals) generated by irradiation of the light 140, and the substances represented by formula 4 or formula 8 may be bonded (crosslinked) to each other by the radicals (e.g., carbon radicals). Thus, in the first portion 122 of the photoresist layer 120, the resist compound may include a crosslinked structure of the substance represented by formula 4 or formula 8. In the second portion 124 of the photoresist layer 120, the chemical structure of the resist compound may not change. As a result, a solubility difference between the first portion 122 and the second portion 124 may occur after the exposure process.

The underlayer compound may include a high absorbance element that absorbs light 140 and emits secondary electrons. The high absorbance element may be, for example, iodine or tin. The high absorbance element in the underlayer compound may absorb light 140 and emit secondary electrons, and thus, the underlayer compound may include secondary electrons generated by the irradiation of light 140. Secondary electrons generated in the exposed portions of the underlayer 110 may diffuse into the first portion 122 of the photoresist layer 120, and thus, may promote cross-linking of the resist compound in the first portion 122 of the photoresist layer 120. In this case, the dose amount required for causing the solubility difference between the first portion 122 and the second portion 124 of the photoresist layer 120 may be reduced, and as a result, the sensitivity and resolution of the photoresist layer 120 may be improved.

The bedding compound may also include radicals generated by the irradiation of light 140. In an embodiment, the c—h bond of the alkyl chain in the bedding compound may be broken by secondary electrons generated by the irradiation of light 140, whereby carbon radicals may be generated. The bedding compound may include radicals (e.g., carbon radicals) generated by irradiation of the light 140, and the substances represented by formula 1 or formula 5 may be bonded (crosslinked) to each other by the radicals (e.g., carbon radicals). Accordingly, the exposed portion of the cushion layer 110 may include a cross-linked structure of the substance represented by formula 1 or formula 5. As a result, the etch resistance of the exposed portions of underlayer 110 may be increased.

In addition, the underlayer compound may form cross-links with the resist compound of the first portion 122 of the photoresist layer 120 by radicals (e.g., carbon radicals). Thus, the first portion 122 of the photoresist layer 120 may be secured to the backing layer 110 by chemical bonding with the backing layer 110, and the adhesion between the first portion 122 of the photoresist layer 120 and the backing layer 110 may be increased. As a result, collapse of the photoresist pattern, which will be explained later, can be suppressed. In this case, an additional heating process (e.g., a baking process) for fixing the photoresist layer 120 to the blanket 110 may be omitted.

Referring to fig. 10, after the exposure process, the photomask 130 may be removed. A developing process may be performed on the exposed photoresist layer 120. The developing process may include removing the second portion 124 of the photoresist layer 120 by using a fluorine-based developing solution or a dry etching process. The fluorine-based developing solution may include, for example, hydrofluoroether (HFE) and/or Perfluorocarbon (PFC). The second portion 124 of the photoresist layer 120 may be selectively removed by a developing process, and the first portion 122 of the photoresist layer 120 may be referred to as a photoresist pattern. The photoresist pattern 122 may be a negative pattern. In the case where the developing process is performed by using a fluorine-based developing solution having a relatively low surface tension, pattern collapse of the photoresist pattern 122 may be minimized.

Referring to fig. 11, the underlayer 110 and the underlayer 100 may be etched using the photoresist pattern 122 as an etching mask. Etching of underlayer 110 and underlayer 100 may include, for example, a wet etching process or a dry etching process. The pad layer 110 may be etched to form a pad layer pattern 110P, and an upper portion of the lower layer 100 may be etched to form a lower pattern 100P. After the lower pattern 100P is formed, the photoresist pattern 122 and the pad pattern 110P may be removed. The lower pattern 100P may be a semiconductor pattern, a conductive pattern, or an insulating pattern in the semiconductor device.

A multi-layered structure formed using a cushion compound according to an embodiment of the inventive concept will be explained.

According to some embodiments, the multilayer structure may include an underlayer 100, a underlayer 110, and a photoresist layer 120 as explained with reference to fig. 8. The underlayer 110 may include underlayer compounds including alternating copolymers comprising repeating units represented by formula 1, or substances represented by formula 5. The photoresist layer 120 may include a resist compound including a fluoroalkyl group. The resist compound may include an alternating copolymer including a repeating unit represented by formula 4, or a substance represented by formula 8.

According to some embodiments, the multilayer structure may include an underlayer 100, a underlayer 110, and a photoresist layer 120 as explained with reference to fig. 9. The photoresist layer 120 may include a first portion 122 exposed to light 140 and a second portion 124 not exposed to light 140. In the first portion 122 of the photoresist layer 120, the resist compound may include radicals generated by irradiation of the light 140, and may include a crosslinked structure of a substance represented by formula 4 or formula 8. In the second portion 124 of the photoresist layer 120, the chemical structure of the resist compound may not change.

The cushion layer 110 may include a portion exposed to the light 140 and a portion not exposed to the light 140. In the exposed portion of the underlayer 110, the underlayer compound may include secondary electrons and radicals generated by irradiation of light 140, and may include a crosslinked structure of a substance represented by formula 1 or formula 5. In addition, the underlayer compound may form a crosslink with the resist compound of the first portion 122 of the photoresist layer 120. Thus, the first portion 122 of the photoresist layer 120 may be secured to the backing layer 110 by chemical bonding with the backing layer 110.

According to some embodiments, the multi-layered structure may include an underlayer 100, a underlayer 110, and a photoresist pattern 122 as explained with reference to fig. 10. The photoresist pattern 122 is identical to the first portion 122 of the photoresist layer 120.

According to the inventive concept, the underlayer may include underlayer compounds comprising high absorbance elements. The high absorbance element of the underlayer compound may absorb light irradiated via the exposure process and emit secondary electrons. Secondary electrons generated in the exposed portion of the underlayer may diffuse into the exposed portion of the photoresist layer, and thus, cross-linking of the resist compound in the exposed portion of the photoresist layer may be promoted. Thus, the dose amount required for the exposure process for causing the solubility difference between the exposed portion and the unexposed portion of the photoresist layer can be reduced, and as a result, the sensitivity and resolution of the photoresist layer can be improved.

In addition, the bedding compound may include radicals generated by light irradiation. In this case, the exposed portion of the underlayer may include a structure of the substance represented by formula 1 or formula 5 crosslinked by a radical (e.g., a carbon radical). As a result, the etching resistance of the exposed portion of the underlayer can be increased.

In addition, the underlayer compound may form crosslinks with the resist compound of the exposed portions of the photoresist layer by radicals (e.g., carbon radicals). Thus, the exposed portion of the photoresist layer may be fixed on the underlayer by chemical bonding with the underlayer, and the adhesion between the exposed portion of the photoresist layer and the underlayer may be increased. As a result, collapse of the photoresist pattern can be suppressed.

Accordingly, it is possible to provide a underlayer compound capable of improving resolution and sensitivity of a photoresist layer, suppressing collapse of a photoresist pattern, and having improved etching resistance, a multilayer structure formed by using the underlayer compound, and a method for manufacturing a semiconductor device using the underlayer compound.

Although the embodiments of the present invention have been described, it is understood that the present invention should not be limited to the embodiments, but various changes and modifications can be made by one of ordinary skill in the art within the spirit and scope of the present invention as claimed.

Claims

1. A lithographic underlayer compound comprising an alternating copolymer comprising a repeating unit represented by formula 1 below or an alkylated tin oxide nanocluster having a counter anion:

1 (1)

In formula 1, R ₁ Alkyl of 1 to 18 carbon atoms, R ₂ 、R ₃ 、R ₄ And R is ₅ Each independently hydrogen, deuterium or alkyl of 1 to 3 carbon atoms, A is iodine or tin with alkyl groups, and n is an integer of 2 to 10000,

wherein the alkylated tin oxide nanocluster comprises a core structure comprising tin oxide and an alkyl group of 1 to 18 carbon atoms bonded to the tin atoms of the core structure, and the counter anion is an alkylbenzenesulfonate anion.

2. The underlayer compound for lithography according to claim 1, wherein the tin having an alkyl group is a functional group represented by the following formula 2:

2, 2

3. A lithographic underlayer compound according to claim 2, wherein the alternating copolymer comprises a repeating unit represented by formula 3 below:

3

In formula 3, R ₁ Alkyl of 1 to 18 carbon atoms, a is iodine or a functional group represented by formula 2, and n is an integer of 2 to 10000.

4. A lithographic underlayer compound according to claim 3, wherein the alternating copolymer comprises repeating units represented by the following formula 3-2 or formula 3-3:

3-2

3-3

In the formulas 3-2 and 3-3, n is an integer of 2 to 10000.

5. A lithographic underlayer compound according to claim 1, wherein the alkylated tin oxide nanoclusters with a counter anion comprise the structure of formula 5 below:

5. The method is to

In formula 5, R is an alkyl group of 1 to 18 carbon atoms, and Rx ^- Is a counter anion and is an alkylbenzenesulfonate anion.

6. The lithographic underlayer compound of claim 5, where Rx ^- Has the structure of formula 6 below:

6. The method is to

In formula 6, R ₉ Alkyl of 1 to 18 carbon atoms.

7. The underlayer compound for lithography of claim 6, where R ₉ with-CH ₂ (CH ₂ ) ₁₀ CH ₃ Is a structure of (a).

8. The lithographic underlayer compound of claim 7, where R is butyl.

9. A multilayer structure, the multilayer structure comprising:

a lower layer;

a cushion layer positioned on the lower layer; and

a photoresist layer, located on the pad layer,

wherein the underlayer comprises an alternating copolymer comprising a repeating unit represented by formula 1 below or alkylated tin oxide nanoclusters having counter anions:

1 (1)

10. The multilayer structure of claim 9, wherein the tin having an alkyl group is a functional group represented by the following formula 2:

2, 2

11. The multilayer structure of claim 9 wherein the alkylated tin oxide nanoclusters having a counter anion include the structure of formula 5:

5. The method is to

12. The multilayer structure of claim 11, wherein Rx is ^- Has the structure of formula 6 below:

6. The method is to

In formula 6, R ₉ Alkyl of 1 to 18 carbon atoms.

13. The multilayer structure of claim 11, wherein the cushion layer comprises a crosslinked structure of the substance represented by formula 1 or formula 5.

14. The multilayer structure of claim 13, wherein the photoresist layer comprises a fluoroalkyl containing resist compound, and

the underlayer includes a structure in which a substance represented by formula 1 or formula 5 is crosslinked with a resist compound.

15. A method for manufacturing a semiconductor device, the method comprising the steps of:

forming a cushion layer on the lower layer; and

a photoresist layer is formed on the blanket layer,

wherein the step of forming the underlayer comprises applying an underlayer compound onto the underlayer, the underlayer compound comprising an alternating copolymer comprising a repeating unit represented by formula 1 below, or an alkylated tin oxide nanocluster having a counter anion:

1 (1)

16. The method for manufacturing a semiconductor device according to claim 15, wherein the alkylated tin oxide nanocluster having a counter anion includes a structure of formula 5 below:

5. The method is to

17. The method for manufacturing a semiconductor device according to claim 16, wherein the step of forming the photoresist layer comprises applying a resist compound including a fluoroalkyl group on the underlayer using a fluorine-based solvent.

18. The method for manufacturing a semiconductor device according to claim 17, further comprising performing an exposure process on the photoresist layer,

wherein the exposure process is performed using an electron beam or extreme ultraviolet rays.

19. The method for manufacturing a semiconductor device according to claim 18, wherein the underlayer comprises a crosslinked structure of a substance represented by formula 1 or formula 5 after the exposure process.

20. The method for manufacturing a semiconductor device according to claim 18, wherein the photoresist layer includes a first portion exposed to an exposure process and a second portion not exposed to the exposure process, and

the method further comprises the steps of:

a second portion of the photoresist layer is selectively removed by performing a developing process.