KR102904140B1 - Semiconductor photoresist composition and method of forming patterns using the composition - Google Patents

Abstract

The present invention relates to a composition for a semiconductor photoresist, comprising an organic tin compound having four tin atoms in the molecule, each of which contains a tin (Sn)-carbon (C) bond and at least one substituent having a hydrolyzable bond to the tin, and a solvent, and a method for forming a pattern using the same.

Description

Semiconductor photoresist composition and method of forming patterns using the same {SEMICONDUCTOR PHOTORESIST COMPOSITION AND METHOD OF FORMING PATTERNS USING THE COMPOSITION}

The present invention relates to a composition for semiconductor photoresist and a method for forming a pattern using the same.

Extreme ultraviolet (EUV) lithography is attracting attention as a key technology for manufacturing next-generation semiconductor devices. EUV lithography is a pattern-forming technology that utilizes EUV light with a wavelength of 13.5 nm as an exposure light source. EUV lithography has been demonstrated to be capable of forming extremely fine patterns (e.g., 20 nm or less) during the exposure process of semiconductor device manufacturing.

The implementation of extreme ultraviolet (EUV) lithography requires the development of compatible photoresists capable of performing at spatial resolutions down to 16 nm. Currently, conventional chemically amplified (CA) photoresists struggle to meet the resolution, photospeed, feature roughness, and line edge roughness (LER) specifications for next-generation devices.

Intrinsic image blur due to acid-catalyzed reactions in these polymeric photoresists limits resolution at small feature sizes, a problem long known in electron-beam lithography. Chemically amplified (CA) photoresists are designed for high sensitivity, but can struggle more under EUV exposure, in part because their typical elemental makeup lowers their absorbance at a wavelength of 13.5 nm, thereby reducing their sensitivity.

CA photoresists can also suffer from roughness issues at small feature sizes, and experimentally have shown that line edge roughness (LER) increases with decreasing photospeed, partly due to the nature of acid-catalyzed processes. Due to the shortcomings and issues with CA photoresists, there is a need in the semiconductor industry for new types of high-performance photoresists.

To overcome the shortcomings of the chemically amplified organic photosensitive compositions described above, inorganic photosensitive compositions have been studied. Inorganic photosensitive compositions are primarily used for negative tone patterning, which is resistant to removal by developer compositions due to chemical modification by a non-chemically amplified mechanism. Inorganic compositions contain inorganic elements with higher EUV absorption than hydrocarbons, enabling them to maintain sensitivity even through a non-chemically amplified mechanism. They are also known to be less susceptible to stochastic effects, resulting in fewer line edge roughness and fewer defects.

Inorganic photoresists based on peroxopolyacids of tungsten and tungsten mixed with niobium, titanium, and/or tantalum have been reported for patterning radiation sensitive materials (US5061599; H. Okamoto, T. Iwayanagi, K. Mochiji, H. Umezaki, T. Kudo, Applied Physics Letters, 49(5), 298-300, 1986).

These materials have been effective in patterning large features in a bilayer configuration with deep UV, x-ray, and electron beam sources. More recently, impressive performance has been demonstrated using cationic hafnium metal oxide sulfate (HfSOx) materials in combination with a peroxo complexing agent to image 15 nm half-pitch (HP) features by projection EUV lithography (US2011-0045406; J. K. Stowers, A. Telecky, M. Kocsis, B. L. Clark, D. A. Keszler, A. Grenville, C. N. Anderson, P. P. Naulleau, Proc. SPIE, 7969, 796915, 2011). This system demonstrated the best performance of any non-CA photoresist and possessed a photovoltaic speed approaching the requirements for viable EUV photoresists. However, hafnium metal oxide sulfate materials with peroxo complexing agents have several practical drawbacks. First, these materials are coated in a highly corrosive sulfuric acid/hydrogen peroxide mixture, resulting in poor shelf-life stability. Second, as a complex mixture, structural modification for performance improvement is not easily possible. Third, they must be developed in extremely high concentrations, such as 25 wt% tetramethylammonium hydroxide (TMAH) solutions.

Recently, active research has been conducted on tin-containing molecules that exhibit excellent extreme ultraviolet absorption. Organotin polymers, for example, enable negative-tone patterning that is not removed by organic developers through cross-linking via oxo bonds with surrounding chains, resulting from the dissociation of alkyl ligands by light absorption or the secondary electrons generated by light absorption. These organotin polymers have demonstrated dramatic improvements in sensitivity while maintaining resolution and line edge roughness. However, further improvements in these patterning characteristics are necessary for commercialization.

One embodiment provides a composition for a semiconductor photoresist capable of implementing a pattern with significantly improved sensitivity while maintaining line edge roughness.

Another embodiment provides a method for forming a pattern using the composition for semiconductor photoresist.

A composition for a semiconductor photoresist according to one embodiment comprises an organotin compound having four tin atoms in the molecule, each of which contains a tin (Sn)-carbon (C) bond and at least one substituent having a hydrolyzable bond to the tin, and a solvent.

The substituent having the hydrolyzable bond is a halogen, a thiol group, an amino group (-NR ^a R ^b , wherein R ^a and R ^b are each independently hydrogen or a hydrocarbon group having 1 to 30 carbon atoms), a silyloxo group (-OSiR ^a R ^b R ^c , wherein R ^a , R ^b , and R ^c are each independently a hydrocarbon group having 1 to 30 carbon atoms), a silylamino group (-N(SiR ^a ₃ )(R ^b ), wherein R ^a and R ^b are each independently a hydrocarbon group having 1 to 30 carbon atoms), a disilylamino group (-N(SiR ^a ₃ )(SiR ^b ₃ ), wherein R ^a and R ^b are each independently a hydrocarbon group having 1 to 30 carbon atoms), an alkoxy group, and an aryloxo group (-OR ^a , wherein R ^a is hydrogen or an alkyl or aryl group having 1 to 30 carbon atoms). It can be selected from the group consisting of a carboxyl group (-O(COR ^a ), where R ^a is hydrogen or a hydrocarbon group having 1 to 30 carbon atoms), an azido group (-N ₃ ), an alkyne group (-C≡CR ^a , where R ^a is a hydrocarbon group having 1 to 30 carbon atoms), an amido group (-NR ^a (COR ^b ), where R ^a and R ^b are each independently hydrogen or a hydrocarbon group having 1 to 30 carbon atoms), an amidinato (-NR ^a C(NR ^b )R ^c , where R ^a , R ^b , and R ^c are each independently hydrogen or a hydrocarbon group having 1 to 30 carbon atoms), an imido group (-N(COR ^a )(COR ^b ), where R ^a and R ^b are each independently hydrogen or a hydrocarbon group having 1 to 30 carbon atoms), or a combination thereof.

The above organic tin compound can be represented by the following chemical formula 1.

[Chemical Formula 1]

₍ X ¹ _m1 (R ¹ ) _3-m1 SnOSn(R ² ) _{3 -} ^m2

In the above chemical formula 1,

X ¹ and X ² are each independently selected from halogen, -N ₃ , -NR ³ R ⁴ , -O(COR ⁵ ), -NR ⁶ (COR ⁷ ), -NR ⁸ C(NR ⁹ )R ¹⁰ , -N(COR ¹¹ )(COR ¹² ), OSiR ¹³ R ¹⁴ R ¹⁵ , -N(SiR ¹⁶ ₃ )(R ¹⁷ ), -N(SiR ¹⁸ ₃ )(SiR ¹⁹ ₃ ), OR ²⁰ , SR ²¹ , and -C≡CR ²² ,

R ¹ to R ²² are each independently hydrogen, halogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C3 to C20 cycloalkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C3 to C20 cycloalkynyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof,

m1 and m2 are each independently an integer from 1 to 3.

The above X ¹ and X ² are each independently halogen, -O(COR ⁵ ), OR ²⁰ or SR ²¹ ,

R ⁵ , R ²⁰ and R ²¹ may each independently be hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof.

At least one of the above X ¹ and X ² is -O(COR ⁵ ),

R ⁵ may be hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof.

The above organic tin compound can be represented by the following chemical formula 2 or chemical formula 3.

[Chemical Formula 2] [Chemical Formula 3]

In the above chemical formulas 2 and 3,

R ¹ and R ² are each independently a substituted or unsubstituted C1 to C20 alkyl group,

R ²¹ to R ³² are each independently hydrogen or a substituted or unsubstituted C1 to C20 alkyl group.

The above R ¹ and R ² can each independently be a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, a tert-butyl group, a 2,2-dimethylpropyl group, or a combination thereof.

The above organic tin compound may include any one or a combination of compounds listed in Group 1 below.

[Group 1]

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

[Chemical Formula 7]

Based on 100 wt% of the composition for the semiconductor photoresist, the organic tin compound may be included in an amount of 1 wt% to 30 wt%.

The composition for the semiconductor photoresist may further include an additive such as a surfactant, a cross-linking agent, a leveling agent, or a combination thereof.

A pattern forming method according to another embodiment includes a step of forming an etching target film on a substrate, a step of forming a photoresist film by applying the aforementioned semiconductor photoresist composition on the etching target film, a step of patterning the photoresist film to form a photoresist pattern, and a step of etching the etching target film using the photoresist pattern as an etching mask.

The step of forming the above photoresist pattern can use light with a wavelength of 5 nm to 150 nm.

The above pattern forming method may further include a step of providing a resist underlayer film formed between the substrate and the photoresist film.

The above photoresist pattern may have a width of 5 nm to 100 nm.

A composition for a semiconductor photoresist according to one embodiment can provide a photoresist pattern with improved sensitivity while maintaining line edge roughness.

FIGS. 1 to 5 are cross-sectional views illustrating a pattern forming method using a composition for semiconductor photoresist according to one embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. However, in describing this disclosure, descriptions of functions or configurations already known will be omitted to clarify the gist of this disclosure.

To clarify this description, irrelevant parts have been omitted, and identical or similar components are designated by the same reference numerals throughout the specification. Furthermore, the size and thickness of each component shown in the drawings are arbitrarily indicated for convenience of explanation, and therefore this description is not necessarily limited to what is shown.

To clearly illustrate various layers and regions in the drawings, their thicknesses have been enlarged. Furthermore, for convenience of explanation, the thicknesses of some layers and regions have been exaggerated in the drawings. When a layer, membrane, region, plate, or other part is said to be "over" or "on" another part, this includes not only cases where it is "directly over" another part, but also cases where there is another part in between.

In the present invention, "substitution" means a hydrogen atom is substituted with deuterium, a halogen group, a hydroxyl group, a cyano group, a nitro group, -NRR' (wherein, R and R' are each independently hydrogen, a substituted or unsubstituted C1 to C30 saturated or unsaturated aliphatic hydrocarbon group, a substituted or unsubstituted C3 to C30 saturated or unsaturated alicyclic hydrocarbon group, or a substituted or unsubstituted C6 to C30 aromatic hydrocarbon group), -SiRR'R" (wherein, R, R', and R" are each independently hydrogen, a substituted or unsubstituted C1 to C30 saturated or unsaturated aliphatic hydrocarbon group, a substituted or unsubstituted C3 to C30 saturated or unsaturated alicyclic hydrocarbon group, or a substituted or unsubstituted C6 to C30 aromatic hydrocarbon group), a C1 to C30 alkyl group, a C1 to C10 haloalkyl group, a C1 to C10 It means substituted with a C10 alkylsilyl group, a C3 to C30 cycloalkyl group, a C6 to C30 aryl group, a C1 to C20 alkoxy group, or a combination thereof. "Unsubstituted" means that a hydrogen atom is not replaced by another substituent and remains a hydrogen atom.

As used herein, "alkyl group" means a straight-chain or branched-chain aliphatic hydrocarbon group, unless otherwise defined. The alkyl group may be a "saturated alkyl group" that does not contain any double bond or triple bond.

The alkyl group may be a C1 to C10 alkyl group. For example, the alkyl group may be a C1 to C8 alkyl group, a C1 to C7 alkyl group, a C1 to C6 alkyl group, a C1 to C5 alkyl group, or a C1 to C4 alkyl group. For example, the C1 to C4 alkyl group may be a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, or a 2,2-dimethylpropyl group.

In this description, “cycloalkyl group” means a monovalent cyclic aliphatic saturated hydrocarbon group, unless otherwise defined.

The cycloalkyl group can be a C3 to C10 cycloalkyl group, for example, a C3 to C8 cycloalkyl group, a C3 to C7 cycloalkyl group, a C3 to C6 cycloalkyl group, a C3 to C5 cycloalkyl group, or a C3 to C4 cycloalkyl group. For example, the cycloalkyl group can be, but is not limited to, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, or a cyclohexyl group.

As used herein, "aryl group" means a substituent in which all atoms of the cyclic substituent have p-orbitals and these p-orbitals form conjugation, and includes a monocyclic or fused ring polycyclic (i.e., a ring that shares adjacent pairs of carbon atoms) functional groups.

In this specification, unless otherwise defined, “alkenyl group” means an aliphatic unsaturated alkenyl group, which is a straight-chain or branched-chain aliphatic hydrocarbon group containing one or more double bonds.

In this specification, unless otherwise defined, “alkynyl group” means a straight-chain or branched-chain aliphatic hydrocarbon group, which is an aliphatic unsaturated alkynyl group containing one or more triple bonds.

In the chemical formula described herein, t-Bu means a tert-butyl group.

A composition for semiconductor photoresist according to the following implementation example is described.

A composition for a semiconductor photoresist according to one embodiment of the present invention comprises an organic tin compound having four tin atoms in the molecule, each of which includes a tin (Sn)-carbon (C) bond and at least one substituent having a hydrolyzable bond to the tin, and a solvent.

According to one embodiment, a composition for a semiconductor photoresist is not a monomer type containing one tin in a molecule, but a type in which four tin atoms are connected in a ladder type, and thus the amount of tin is high compared to the organic material, so that sensitivity can be improved.

The above organic tin compound may include at least one substituent having a tin-carbon bond and a hydrolyzable bond to the tin.

The substituent having the hydrolyzable bond is a halogen, a thiol group, an amino group (-NR ^a R ^b , wherein R ^a and R ^b are each independently hydrogen or a hydrocarbon group having 1 to 30 carbon atoms), a silyloxo group (-OSiR ^a R ^b R ^c , wherein R ^a , R ^b , and R ^c are each independently a hydrocarbon group having 1 to 30 carbon atoms), a silylamino group (-N(SiR ^a ₃ )(R ^b ), wherein R ^a and R ^b are each independently a hydrocarbon group having 1 to 30 carbon atoms), a disilylamino group (-N(SiR ^a ₃ )(SiR ^b ₃ ), wherein R ^a and R ^b are each independently a hydrocarbon group having 1 to 30 carbon atoms), an alkoxy group, and an aryloxo group (-OR ^a , wherein R ^a is hydrogen or an alkyl or aryl group having 1 to 30 carbon atoms). It can be selected from the group consisting of a carboxyl group (-O(COR ^a ), where R ^a is hydrogen or a hydrocarbon group having 1 to 30 carbon atoms), an azido group (-N ₃ ), an alkyne group (-C≡CR ^a , where R ^a is a hydrocarbon group having 1 to 30 carbon atoms), an amido group (-NR ^a (COR ^b ), where R ^a and R ^b are each independently hydrogen or a hydrocarbon group having 1 to 30 carbon atoms), an amidinato (-NR ^a C(NR ^b )R ^c , where R ^a , R ^b , and R ^c are each independently hydrogen or a hydrocarbon group having 1 to 30 carbon atoms), an imido group (-N(COR ^a )(COR ^b ), where R ^a and R ^b are each independently hydrogen or a hydrocarbon group having 1 to 30 carbon atoms), or a combination thereof.

For example, the organic tin compound may be represented by the following chemical formula 1.

[Chemical Formula 1]

₍ X ¹ _m1 (R ¹ ) _3-m1 SnOSn(R ² ) _{3 -} ^m2

In the above chemical formula 1,

X ¹ and X ² are each independently selected from halogen, -N ₃ , -NR ³ R ⁴ , -O(COR ⁵ ), -NR ⁶ (COR ⁷ ), -NR ⁸ C(NR ⁹ )R ¹⁰ , -N(COR ¹¹ )(COR ¹² ), OSiR ¹³ R ¹⁴ R ¹⁵ , -N(SiR ¹⁶ ₃ )(R ¹⁷ ), -N(SiR ¹⁸ ₃ )(SiR ¹⁹ ₃ ), OR ²⁰ , SR ²¹ , and -C≡CR ²² ,

R ¹ to R ²² are each independently hydrogen, halogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C3 to C20 cycloalkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C3 to C20 cycloalkynyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof,

m1 and m2 are each independently an integer from 1 to 3.

For example, the above X ¹ and X ² are each independently halogen, -O(COR ⁵ ), OR ²⁰ or SR ²¹ ,

R ⁵ , R ²⁰ and R ²¹ may each independently be hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof.

For example, at least one of the above X ¹ and X ² is -O(COR ⁵ ),

R ⁵ may be hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof.

In one embodiment, the organic tin compound may be represented by the following chemical formula 2 or chemical formula 3.

[Chemical Formula 2] [Chemical Formula 3]

In the above chemical formulas 2 and 3,

R ¹ and R ² are each independently a substituted or unsubstituted C1 to C20 alkyl group,

R ²¹ to R ³² are each independently hydrogen or a substituted or unsubstituted C1 to C20 alkyl group.

As a most specific example, R ¹ and R ² may each independently be a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, a tert-butyl group, a 2,2-dimethylpropyl group, or a combination thereof.

More specific examples of the above organic tin compounds include the compounds listed in Group 1 below.

[Group 1]

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

[Chemical Formula 7]

Tin can strongly absorb extreme ultraviolet light at 13.5 nm, giving it excellent sensitivity to high-energy light.

In a semiconductor photoresist composition according to one embodiment, the organic tin compound may be included in an amount of 1 wt% to 30 wt%, for example, 1 wt% to 25 wt%, for example, 1 wt% to 20 wt%, for example, 1 wt% to 15 wt%, for example, 1 wt% to 10 wt%, for example, 1 wt% to 5 wt%, based on 100 wt% of the composition for semiconductor photoresist, but is not limited thereto. When the organic tin compound is included in an amount within the above range, the storage stability and etch resistance of the composition for semiconductor photoresist are improved, and the resolution characteristics are improved.

According to the present invention, a composition for a semiconductor photoresist having excellent sensitivity and pattern formation properties can be provided.

The solvent included in the semiconductor resist composition according to one embodiment may be an organic solvent, and may include, but is not limited to, aromatic compounds (e.g., xylene, toluene), alcohols (e.g., 4-methyl-2-pentanol (MIBC), 4-methyl-2-propanol, 1-butanol, methanol, isopropyl alcohol, 1-propanol), ethers (e.g., anisole, tetrahydrofuran), esters (n-butyl acetate, propylene glycol methyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), ethyl acetate, ethyl lactate), ketones (e.g., methyl ethyl ketone, 2-heptanone), mixtures thereof, and the like.

In one embodiment, the semiconductor resist composition may further include a resin in addition to the organic tin compound and solvent described above.

The above resin may be a phenolic resin containing at least one aromatic moiety listed in Group 2 below.

[Group 2]

The above resin may have a weight average molecular weight of 500 to 20,000.

The above resin may be included in an amount of 0.1 wt% to 50 wt% based on the total content of the composition for the semiconductor resist.

When the above resin is contained in the above content range, it can have excellent etch resistance and heat resistance.

Meanwhile, the semiconductor resist composition according to one embodiment preferably comprises the aforementioned organic tin compound, solvent, and resin. However, the semiconductor resist composition according to the aforementioned embodiment may further comprise additives, as the case may be. Examples of the additives include surfactants, crosslinking agents, leveling agents, organic acids, quenchers, or combinations thereof.

Surfactants may include, but are not limited to, alkylbenzenesulfonic acid salts, alkylpyridinium salts, polyethylene glycols, quaternary ammonium salts, or combinations thereof.

Examples of the crosslinking agent include, but are not limited to, a melamine-based crosslinking agent, a substituted urea-based crosslinking agent, an acrylic-based crosslinking agent, an epoxy-based crosslinking agent, or a polymer-based crosslinking agent. As a crosslinking agent having at least two crosslinking-forming substituents, for example, compounds such as methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxymethylated benzoguanamine, 4-hydroxybutyl acrylate, acrylic acid, urethane acrylate, acrylic methacrylate, 1,4-butanediol diglycidyl ether, glycidol, diglycidyl 1,2-cyclohexane dicarboxylate, trimethylpropane triglycidyl ether, 1,3-bis(glycidoxypropyl_)tetramethyldisiloxane, methoxymethylated urea, butoxymethylated urea, or methoxymethylated thiourea can be used.

The leveling agent is used to improve the coating flatness during printing, and any known leveling agent available commercially can be used.

The organic acid may be, but is not limited to, p-toluenesulfonic acid, benzenesulfonic acid, p-dodecylbenzenesulfonic acid, 1,4-naphthalenedisulfonic acid, methanesulfonic acid, a fluorinated sulfonium salt, malonic acid, citric acid, propionic acid, methacrylic acid, oxalic acid, lactic acid, glycolic acid, succinic acid, or a combination thereof.

The quencher may be diphenyl(p-trimethyl)amine, methyl diphenyl amine, triphenyl amine, phenylenediamine, naphthylamine, diaminonaphthalene, or a combination thereof.

The amount of these additives used can be easily adjusted according to the desired properties and may be omitted.

In addition, the semiconductor resist composition may further use a silane coupling agent as an additive as an adhesion promoter to improve adhesion to a substrate (e.g., to improve adhesion of the semiconductor resist composition to a substrate). The silane coupling agent may be, but is not limited to, a carbon-carbon unsaturated bond-containing silane compound such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane; or 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, p-styryl trimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane; or trimethoxy[3-(phenylamino)propyl]silane.

The above composition for semiconductor photoresist can form a pattern having a high aspect ratio without causing pattern collapse. Therefore, for example, a photoresist process using light having a wavelength of 5 nm to 150 nm, for example, a photoresist process using light having a wavelength of 5 nm to 100 nm, for example, a photoresist process using light having a wavelength of 5 nm to 80 nm, for example, a photoresist process using light having a wavelength of 5 nm to 50 nm, for example, a photoresist process using light having a wavelength of 5 nm to 80 nm, for example, a photoresist process using light having a wavelength of 5 nm to 50 nm, for example, a photoresist process using light having a wavelength of 5 nm to 30 nm, for example, a photoresist process using light having a wavelength of 5 nm to 30 nm, for example, a photoresist process using light having a wavelength of 5 nm to 20 nm, for example, For example, it can be used in a photoresist process using light with a wavelength of 5 nm to 20 nm. Therefore, by using the composition for semiconductor photoresist according to one embodiment, extreme ultraviolet lithography using an EUV light source with a wavelength of about 13.5 nm can be implemented.

Meanwhile, according to another embodiment, a method for forming a pattern using the above-described semiconductor photoresist composition may be provided. For example, the pattern formed may be a photoresist pattern.

Another embodiment of the method for forming a pattern includes the steps of forming an etching target film on a substrate, applying the aforementioned semiconductor photoresist composition on the etching target film to form a photoresist film, patterning the photoresist film to form a photoresist pattern, and etching the etching target film using the photoresist pattern as an etching mask.

Hereinafter, a method for forming a pattern using the above-described semiconductor photoresist composition will be described with reference to FIGS. 1 to 5. FIGS. 1 to 5 are cross-sectional views for explaining a method for forming a pattern using the semiconductor photoresist composition according to the present invention.

Referring to Fig. 1, first, an etching target is prepared. An example of the etching target may be a thin film (102) formed on a semiconductor substrate (100). The following description will be limited to the case where the etching target is a thin film (102). The surface of the thin film (102) is cleaned to remove contaminants remaining on the thin film (102). The thin film (102) may be, for example, a silicon nitride film, a polysilicon film, or a silicon oxide film.

Next, a composition for forming a resist underlayer film (104) is coated on the surface of the cleaned thin film (102) by applying a spin coating method. However, one embodiment is not necessarily limited thereto, and various known coating methods, for example, spray coating, dip coating, knife edge coating, printing methods such as inkjet printing and screen printing, etc. may be used.

The above resist underlayer coating process can be omitted, and the following describes a case where the resist underlayer is coated.

Thereafter, a drying and baking process is performed to form a resist underlayer film (104) on the thin film (102). The baking process is performed at about 100 to about 500°C, and may be performed at about 100 to about 300°C, for example.

The resist underlayer film (104) is formed between the substrate (100) and the photoresist film (106), so that when the radiation reflected from the interface or interlayer hardmask of the substrate (100) and the photoresist film (106) is scattered into an unintended photoresist region, it can prevent the unevenness of the photoresist linewidth and the interference with the pattern formation.

Referring to FIG. 2, the semiconductor photoresist composition described above is coated on the resist underlayer film (104) to form a photoresist film (106). The photoresist film (106) may be in the form of a thin film (102) formed on a substrate (100) coated with the semiconductor photoresist composition described above and then cured through a heat treatment process.

More specifically, the step of forming a pattern using a composition for semiconductor photoresist may include a step of applying the above-described composition for semiconductor photoresist onto a substrate (100) on which a thin film (102) is formed by spin coating, slit coating, inkjet printing, etc., and a step of drying the applied composition for semiconductor photoresist to form a photoresist film (106).

Since the composition for semiconductor photoresist has already been described in detail, a duplicate description will be omitted.

Next, a first baking process is performed to heat the substrate (100) on which the photoresist film (106) is formed. The first baking process can be performed at a temperature of about 80°C to about 120°C.

Referring to FIG. 3, the photoresist film (106) is selectively exposed.

For example, examples of light that can be used in the above exposure process include light having a short wavelength, such as an activating irradiance i-line (wavelength 365 nm), a KrF excimer laser (wavelength 248 nm), and an ArF excimer laser (wavelength 193 nm), as well as light having a high energy wavelength, such as EUV (Extreme UltraViolet; wavelength 13.5 nm) and E-Beam (electron beam).

More specifically, the exposure light according to one embodiment may be short-wavelength light having a wavelength range of 5 nm to 150 nm, and may be light having a high-energy wavelength such as EUV (Extreme UltraViolet; wavelength 13.5 nm) or E-Beam (electron beam).

The exposed area (106b) of the photoresist film (106) forms a polymer through a cross-linking reaction such as condensation between organometallic compounds, and thus has a different solubility from the unexposed area (106a) of the photoresist film (106).

Next, a second baking process is performed on the substrate (100). The second baking process can be performed at a temperature of about 90° C. to about 200° C. By performing the second baking process, the exposed area (106b) of the photoresist film (106) becomes difficult to dissolve in a developer.

In Fig. 4, a photoresist pattern (108) formed by dissolving and removing a photoresist film (106a) corresponding to the unexposed area using a developer is illustrated. Specifically, the photoresist pattern (108) corresponding to the negative tone image is completed by dissolving and then removing the photoresist film (106a) corresponding to the unexposed area using an organic solvent such as 2-heptanone.

As described above, the developer used in the pattern forming method according to one embodiment may be an organic solvent. Examples of the organic solvent used in the pattern forming method according to one embodiment include ketones such as methyl ethyl ketone, acetone, cyclohexanone, and 2-heptanone; alcohols such as 4-methyl-2-propanol, 1-butanol, isopropanol, 1-propanol, and methanol; esters such as propylene glycol monomethyl ether acetate, ethyl acetate, ethyl lactate, n-butyl acetate, and butyrolactone; aromatic compounds such as benzene, xylene, and toluene; or combinations thereof.

However, the photoresist pattern according to one embodiment is not necessarily limited to being formed as a negative tone image, and may also be formed to have a positive tone image. In this case, a developer that can be used to form a positive tone image may include a quaternary ammonium hydroxide composition such as tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, or a combination thereof.

As described above, the photoresist pattern (108) formed by exposure to light having a wavelength such as i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), or light having high energy such as EUV (Extreme UltraViolet; wavelength 13.5 nm) or E-Beam (electron beam) may have a width of 5 nm to 100 nm. For example, the photoresist pattern (108) may be formed to have a width of 5 nm to 90 nm, 5 nm to 80 nm, 5 nm to 70 nm, 5 nm to 60 nm, 5 nm to 50 nm, 5 nm to 40 nm, 5 nm to 30 nm, or 5 nm to 20 nm.

Meanwhile, the photoresist pattern (108) may have a pitch having a half-pitch of about 50 nm or less, for example, 40 nm or less, for example, 30 nm or less, for example, 20 nm or less, for example, 15 nm or less, and a line width roughness of about 10 nm or less, about 5 nm or less, about 3 nm or less, or about 2 nm or less.

Next, the resist underlayer film (104) is etched using the photoresist pattern (108) as an etching mask. An organic film pattern (112) is formed through the etching process described above. The formed organic film pattern (112) may also have a width corresponding to the photoresist pattern (108).

Referring to FIG. 5, the photoresist pattern (108) is applied as an etching mask to etch the exposed thin film (102). As a result, the thin film is formed into a thin film pattern (114).

The etching of the above thin film (102) can be performed by dry etching using, for example, an etching gas, and the etching gas can be, for example, CHF ₃ , CF ₄ , Cl ₂ , BCl ₃ , or a mixed gas thereof.

In the previously performed exposure process, the thin film pattern (114) formed using the photoresist pattern (108) formed by the exposure process performed using the EUV light source may have a width corresponding to the photoresist pattern (108). For example, it may have a width of 5 nm to 100 nm, similar to the photoresist pattern (108). For example, the thin film pattern (114) formed by the exposure process performed using the EUV light source may have a width of 5 nm to 90 nm, 5 nm to 80 nm, 5 nm to 70 nm, 5 nm to 60 nm, 5 nm to 50 nm, 5 nm to 40 nm, 5 nm to 30 nm, 5 nm to 20 nm, similar to the photoresist pattern (108), and more specifically, it may be formed with a width of 20 nm or less.

Hereinafter, the present invention will be described in more detail through examples relating to the preparation of the semiconductor photoresist composition described above. However, the technical features of the present invention are not limited by the following examples.

(Synthesis of organic tin compounds)

Synthesis Example 1

In a 100 mL round-bottom flask, 10 g (40.17 mmol) of dibutyltin oxide and 1.8 g (40.17 mmol) of formic acid were added to 10 mL of MeOH (methanol), and the mixture was heated and refluxed for 24 hours. Afterwards, the solvent was completely removed by vacuum drying to obtain a compound represented by the following chemical formula 4.

[Chemical Formula 4]

Synthesis Example 2

In a 100 mL round-bottom flask, 10 g (40.17 mmol) of dibutyltin oxide and 2.4 g (40.17 mmol) of acetic acid were added to 10 mL of MeOH and heated under reflux for 24 hours. Afterwards, the solvent was completely removed by vacuum drying to obtain a compound represented by the following chemical formula 5.

[Chemical Formula 5]

Synthesis Example 3

In a 100 mL round-bottom flask, 10 g (40.17 mmol) of diisobutyltin oxide and 2.4 g (40.17 mmol) of acetic acid were added to 10 mL of MeOH and heated under reflux for 24 hours. Afterwards, the solvent was completely removed by vacuum drying to obtain a compound represented by the following chemical formula 6.

[Chemical Formula 6]

Synthesis Example 4

In a 100 mL round-bottom flask, 10 g (47.89 mmol) of butyl stannoic acid and 6.6 g (143.66 mmol) of formic acid were added to 10 mL of MeOH and heated under reflux for 24 hours. Afterwards, the solvent was completely removed by vacuum drying to obtain a compound represented by the following chemical formula 7.

[Chemical Formula 7]

Comparative synthesis example 1

In a 100 mL round-bottom flask, 10 g (25.44 mmol) of iPrSnPh _{3 and} 4.6 g (76.31 mmol) of acetic acid were dissolved in 35 mL of acetonitrile and heated under reflux for 24 hours. Afterwards, the solvent was completely removed by vacuum drying to obtain a compound represented by the following chemical formula 8.

[Chemical Formula 8]

Comparative synthesis example 2

In a 100 mL round-bottom flask, 5 g (102.03 mmol) of LiNMe ₂ was dissolved in anhydrous hexane, and the flask was cooled to -78°C. 8.2 g (34.01 mmol) of isopropyltin trichloride was slowly added dropwise, and the mixture was reacted at room temperature (23°C) for 24 hours. Upon completion of the reaction, the mixture was filtered, concentrated, and dried under vacuum to obtain a compound represented by the following chemical formula 9.

[Chemical Formula 9]

Comparative synthesis example 3

Acetic acid 2.38 g (39.67 mmol) was slowly added dropwise to 10 g (13.2 mmol) of a compound represented by the following chemical formula 10 at room temperature, and then heated and refluxed at 110°C for 24 hours.

[Chemical Formula 10]

Afterwards, the temperature was lowered to room temperature and acetic acid was distilled under vacuum to obtain a compound represented by the following chemical formula 11.

[Chemical Formula 11]

Solubility evaluation

The organotin compounds obtained from Synthetic Examples 1 to 4 and Comparative Synthetic Examples 1 to 3 were dissolved in PGMEA, PGME, MIBC, and Xylene, respectively, at a solid content of 3 wt%, and then observed for dispersions or precipitates after 1 hour. If the compound existed as a solution in a dissolved state as in the beginning, it was marked as ‘○’, and if a dispersion or precipitate was observed, it was marked as ‘X’, and the results are shown in Table 1 below.

Solubility PGMEA PGME MIBC Xylene Synthesis Example 1 ○ ○ ○ ○ Synthesis Example 2 ○ ○ ○ ○ Synthesis Example 3 ○ ○ ○ ○ Synthesis Example 4 ○ ○ ○ ○ Comparative synthesis example 1 ○ ○ ○ ○ Comparative synthesis example 2 ○ ○ ○ ○ Comparative synthesis example 3 X ○ X ○

From the results in Table 1, it can be confirmed that the organotin compounds according to Synthetic Examples 1 to 4 have excellent solubility in the above solvents.

Examples 1 to 4 and Comparative Examples 1 to 3: Preparation of compositions for semiconductor photoresists

The compounds obtained in Synthetic Examples 1 to 4 and Comparative Synthetic Examples 1 to 3 were each dissolved in 4-methyl-2-pentanol at a concentration of 1 wt%, and filtered through a 0.1 ㎛ PTFE (polytetrafluoroethylene) syringe filter to prepare photoresist compositions corresponding to Examples 1 to 4 and Comparative Examples 1 to 3.

Formation of photoresist film

A 4-inch diameter circular silicon wafer having a native-oxide surface is used as a substrate for thin film deposition, and prior to depositing the thin film, the wafer is treated in a UV ozone cleaning system for 10 minutes. The compositions for semiconductor photoresists according to Examples 1 to 4 and Comparative Examples 1 to 3 are spin-coated on the treated substrate at 1500 rpm for 30 seconds, and baked at 100° C. for 120 seconds (post-apply bake, PAB) to form a thin film.

Afterwards, the thickness of the film after coating and firing was measured using ellipsometry, and the results were 25 nm for Examples 1 to 4.

For comparative examples 1 to 3, it was 20 nm.

Sensitivity and Line Edge Roughness (LER) Evaluation

A linear array of 50 circular pads each having a diameter of 500 μm was projected onto a wafer coated with the photoresist compositions of Examples 1 to 4 and Comparative Examples 1 to 3 using EUV light (Lawrence Berkeley National Laboratory Micro Exposure Tool, MET). The pad exposure time was adjusted so that an increased EUV dose was applied to each pad.

The resist and substrate were then exposed on a hotplate at 160°C for 120 seconds and then baked (post-exposure bake, PEB). The baked films were then immersed in a developer (2-heptanone) for 30 seconds each, and then rinsed with the same developer for an additional 10 seconds to form a negative-tone image, i.e., to remove the unexposed coating portion. Finally, the process was completed by hotplate baking at 150°C for 2 minutes.

The residual resist thickness of the exposed pad was measured using an ellipsometer. The remaining thickness was measured for each exposure amount and plotted as a function of the exposure amount. Dg (the energy level at which development is complete) was measured for each resist type and is shown in Table 2 below.

The line edge roughness (LER) of the formed lines confirmed from the FE-SEM images was measured and shown in Table 2 below.

Sensitivity (μC/cm ² ) LER (nm) Example 1 106 2.1 Example 2 101 2.2 Example 3 95 2.4 Example 4 89 2.2 Comparative Example 1 122 2.0 Comparative Example 2 135 2.5 Comparative Example 3 128 2.0

From the results in Table 2, it can be confirmed that the patterns formed using the semiconductor photoresist compositions according to Examples 1 to 4 have excellent sensitivity without a significant increase in line edge roughness compared to Comparative Examples 1 to 3.

While specific embodiments of the present invention have been described and illustrated above, it will be apparent to those skilled in the art that the present invention is not limited to the described embodiments, and that various modifications and variations can be made without departing from the spirit and scope of the present invention. Accordingly, such modifications or variations should not be understood individually from the technical spirit or perspective of the present invention, and such modified embodiments should fall within the scope of the claims of the present invention.

100: Substrate 102: Thin film
104: Resist underlayer 106: Photoresist film
106a: Unexposed area 106b: Exposed area
108: Photoresist pattern 112: Organic film pattern
114: Thin film pattern

Claims (14)

An organic tin compound represented by the following chemical formula 1, and
menstruum
Composition for semiconductor photoresist comprising:
[Chemical Formula 1]
₍ X ¹ _m1 (R ¹ ) _3-m1 SnOSn(R ² ) _{3 -} ^m2
In the above chemical formula 1,
X ¹ and X ² are each independently selected from halogen, -N ₃ , -NR ³ R ⁴ , -O(COR ⁵ ), -NR ⁶ (COR ⁷ ), -NR ⁸ C(NR ⁹ )R ¹⁰ , -N(COR ¹¹ )(COR ¹² ), OSiR ¹³ R ¹⁴ R ¹⁵ , -N(SiR ¹⁶ ₃ )(R ¹⁷ ), -N(SiR ¹⁸ ₃ )(SiR ¹⁹ ₃ ), OR ²⁰ , SR ²¹ , and -C≡CR ²² ,
R ¹ to R ²² are each independently hydrogen, halogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C3 to C20 cycloalkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C3 to C20 cycloalkynyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof,
m1 and m2 are each independently an integer from 1 to 3. delete delete In paragraph 1,
The above X ¹ and X ² are each independently halogen, -O(COR ⁵ ), OR ²⁰ or SR ²¹ ,
A composition for a semiconductor photoresist, wherein R ⁵ , R ²⁰ and R ²¹ are each independently hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof. In paragraph 4,
At least one of the above X ¹ and X ² is -O(COR ⁵ ),
A composition for a semiconductor photoresist, wherein R ⁵ is hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof. In paragraph 5,
The organic tin compound is a composition for a semiconductor photoresist, represented by the following chemical formula 2 or chemical formula 3:
[Chemical Formula 2] [Chemical Formula 3]

In the above chemical formulas 2 and 3,
R ¹ and R ² are each independently a substituted or unsubstituted C1 to C20 alkyl group,
R ²¹ to R ³² are each independently hydrogen or a substituted or unsubstituted C1 to C20 alkyl group. In paragraph 6,
A composition for a semiconductor photoresist, wherein the above R ¹ and R ² are each independently a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, a tert-butyl group, a 2,2-dimethylpropyl group, or a combination thereof. In paragraph 1,
The organic tin compound is a composition for a semiconductor photoresist comprising any one or a combination of compounds listed in Group 1 below:
[Group 1]
[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

[Chemical Formula 7]
. In paragraph 1,
A composition for a semiconductor photoresist comprising 1 to 30 wt% of the organic tin compound based on 100 wt% of the composition for a semiconductor photoresist. In paragraph 1,
The composition for semiconductor photoresist further comprises an additive of a surfactant, a cross-linking agent, a leveling agent, or a combination thereof. A step of forming an etching target film on a substrate;
A step of forming a photoresist film by applying a semiconductor photoresist composition according to any one of claims 1 and 4 to 10 on the etching target film;
A step of forming a photoresist pattern by patterning the photoresist film; and
A pattern forming method comprising a step of etching the etching target film using the photoresist pattern as an etching mask. In Article 11,
The step of forming the above photoresist pattern is a pattern forming method using light having a wavelength of 5 nm to 150 nm. In Article 11,
A pattern forming method further comprising the step of providing a resist underlayer film formed between the substrate and the photoresist film. In Article 11,
A method for forming a pattern, wherein the photoresist pattern has a width of 5 nm to 100 nm.