KR20210128795A - Semiconductor resist composition and method of forming patterns using the composition - Google Patents

Abstract

One embodiment of the present invention provides a composition for a semiconductor photoresist having excellent resolution, solubility, and storage stability properties. More specifically, the present invention relates to a composition for a semiconductor photoresist and a method for forming a pattern using the same, wherein the composition for a semiconductor photoresist comprises: an organometallic compound represented by the following chemical formula 1; and a solvent.

Description

A composition for a semiconductor photoresist and a pattern formation method using the same

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

EUV (extreme ultraviolet light) lithography is attracting attention as one of the elemental technologies for manufacturing next-generation semiconductor devices. EUV lithography is a pattern forming technique using EUV light having a wavelength of 13.5 nm as an exposure light source. According to EUV lithography, it has been demonstrated that an extremely fine pattern (for example, 20 nm or less) can be formed in the exposure step of a semiconductor device manufacturing process.

Implementation of extreme ultraviolet (EUV) lithography requires the development of compatible photoresists that can perform at sub- 16 nm spatial resolutions. Currently, traditional chemically amplified (CA) photoresists are used for resolution, photospeed, and feature roughness, line edge roughness or LER for next-generation devices. Efforts are being made to meet specifications.

The intrinsic image blur due to acid catalyzed reactions taking place in these polymeric photoresists limits resolution at small feature sizes, which e-beam This is a fact that has long been known in lithography. Chemically amplified (CA) photoresists are designed for high sensitivity, but because their typical elemental makeup lowers the absorbance of photoresists at a wavelength of 13.5 nm, which in turn reduces sensitivity, may suffer more under EUV exposure.

CA photoresists may also suffer from roughness issues at small feature sizes, due in part to the nature of acid catalyzed processes, as line edge roughness (LER) decreases as photospeed decreases. has been shown to increase experimentally. Due to the drawbacks and problems of CA photoresists, there is a need in the semiconductor industry for new types of high performance photoresists.

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

These materials were effective in patterning large features in a bilayer configuration with deep UV, x-ray, and electron beam sources. More recently, cationic hafnium metal oxide sulfate (HfSOx) materials with a peroxo complexing agent to image 15 nm half-pitch (HP) by projection EUV exposure. showed impressive performance when using ). This system showed the best performance of a non-CA photoresist and had a light speed approaching the requirements for a viable EUV photoresist. 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 and have poor shelf-life stability. Second, it is not easy to change the structure to improve performance as a complex mixture. Third, it should be developed in an extremely high concentration of TMAH (tetramethylammonium hydroxide) solution of about 25 wt%.

In order to overcome the disadvantages of the chemically amplified organic photosensitive composition described above, an inorganic photosensitive composition has been studied. In the case of an inorganic photosensitive composition, it is mainly used for negative tone patterning that is resistant to removal by a developer composition due to chemical modification by a non-chemical amplification mechanism. In the case of an inorganic composition, it contains inorganic elements with higher EUV absorption compared to hydrocarbons, so sensitivity can be secured even with a non-chemical amplification mechanism, and it is less sensitive to the stochastic effect, so it is known that the roughness of the line edge and the number of defects are small. .

Recently, active research is being conducted as it is known that molecules containing tin have excellent absorption of extreme ultraviolet rays. In the case of an organotin polymer, which is one of them, as the alkyl ligand is dissociated by light absorption or secondary electrons generated thereby, negative tone patterning that is not removed with an organic developer is possible through cross-linking through oxo bonds with surrounding chains. Such an organotin polymer showed a dramatic improvement in sensitivity while maintaining resolution and line edge roughness, but further improvement of the patterning properties is required for commercialization.

One embodiment provides a composition for a semiconductor photoresist having excellent resolution, solubility, and storage stability characteristics.

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

The composition for a semiconductor photoresist according to an embodiment includes an organometallic compound represented by the following Chemical Formula 1 and a solvent.

[Formula 1]

In Formula 1,

R is 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 aliphatic unsaturated organic group containing one or more double or triple bonds, a substituted or unsubstituted is a C6 to C30 aryl group, an ethylene oxide group, a propylene oxide group, or a combination thereof,

X, Y, and Z are each independently -SR ¹ or -SC(=O)R ² ,

Wherein R ¹ is 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 a cyclic C6 to C30 aryl group, or a combination thereof,

R ² is 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 an unsubstituted C6 to C30 aryl group, or a combination thereof.

R is a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C3 to C8 cycloalkyl group, a substituted or unsubstituted C2 to C8 aliphatic unsaturated organic group containing one or more double or triple bonds, a substituted or unsubstituted is a C6 to C20 aryl group, an ethylene oxide group, a propylene oxide group, or a combination thereof,

R ¹ is a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C3 to C8 cycloalkyl group, a substituted or unsubstituted C2 to C8 alkenyl group, a substituted or unsubstituted C2 to C8 alkynyl group, a substituted or unsubstituted a C6 to C20 aryl group, or a combination thereof,

R ² is hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C3 to C8 cycloalkyl group, a substituted or unsubstituted C2 to C8 alkenyl group, a substituted or unsubstituted C2 to C8 alkynyl group, a substituted or It may be an unsubstituted C6 to C20 aryl group, or a combination thereof.

The methyl group, ethyl group, propyl group, butyl group, isopropyl group, tert-butyl group, 2,2-dimethylpropyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, ethenyl group, propenyl group, a butenyl group, an ethynyl group, a propynyl group, a butynyl group, a phenyl group, a tolyl group, a xylene group, a benzyl group, an ethylene oxide group, a propylene oxide group, or a combination thereof;

R ¹ is a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, a tert-butyl group, a 2,2-dimethylpropyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, an ethenyl group, a pro a phenyl group, a butenyl group, an ethynyl group, a propynyl group, a butynyl group, a phenyl group, a tolyl group, a xylene group, a benzyl group, or a combination thereof;

R ² is hydrogen, methyl group, ethyl group, propyl group, butyl group, isopropyl group, tert-butyl group, 2,2-dimethylpropyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, ethenyl group , a propenyl group, a butenyl group, an ethynyl group, a propynyl group, a butynyl group, a phenyl group, a tolyl group, a xylene group, a benzyl group, or a combination thereof.

The compound represented by Formula 1 may include a compound represented by Formula 2 below, a compound represented by Formula 3, a compound represented by Formula 4, a compound represented by Formula 5, or a combination thereof.

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

In Formula 2, Formula 3, Formula 4, and Formula 5,

R is 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 aliphatic unsaturated organic group containing one or more double or triple bonds, a substituted or unsubstituted is a C6 to C30 aryl group, an ethylene oxide group, a propylene oxide group, or a combination thereof,

R ^a , R ^b , R ^c , R ⁱ , R ^k , and R ¹ are each independently a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to a 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;

R ^d , ^Re , R ^f , R ^g , R ^h , and R ^j 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 a 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.

Based on 100 wt% of the composition for a semiconductor photoresist, 1 to 30 wt% of the organometallic compound represented by Chemical Formula 1 may be included.

The composition for a semiconductor photoresist may further include an additive of a surfactant, a crosslinking agent, a leveling agent, or a combination thereof.

A pattern forming method according to another embodiment includes forming an etch target film on a substrate, applying the above-described composition for a semiconductor photoresist on the etch target film to form a photoresist film, patterning the photoresist film to form a photoresist pattern and etching the etch target layer using the photoresist pattern as an etch mask.

In the forming of the photoresist pattern, light having a wavelength of 5 nm to 150 nm may be used.

The pattern forming method may further include providing a resist underlayer formed between the substrate and the photoresist layer.

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

Since the composition for a semiconductor photoresist according to an embodiment has relatively excellent resolution and is easy to handle, it can provide a photoresist pattern that has excellent limit resolution and does not collapse even if it has a high aspect ratio. have.

1 to 5 are cross-sectional views for explaining a pattern forming method using a composition for a semiconductor photoresist according to an exemplary embodiment.

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

In order to clearly explain the present description, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification. In addition, since the size and thickness of each component shown in the drawings are arbitrarily indicated for convenience of description, the present description is not necessarily limited to the illustrated bar.

In order to clearly express various layers and regions in the drawings, the thicknesses are enlarged. In addition, in the drawings, thicknesses of some layers and regions are exaggerated for convenience of description. When a part, such as a layer, film, region, plate, etc., is "on" or "on" another part, it includes not only cases where it is "directly on" another part, but also cases where there is another part in between.

In the present description, "substituted" means that a hydrogen atom is 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 an 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" (where 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), C1 to C30 alkyl group, C1 to C10 haloalkyl group, C1 to C10 alkylsilyl group, C3 to C30 cycloalkyl group, C6 to C30 aryl group, C1 to C20 alkoxy group, or a combination thereof means that "Unsubstituted" means that a hydrogen atom remains as a hydrogen atom without being substituted with another substituent.

As used herein, the term "alkyl group" refers to 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 or triple bonds.

The alkyl group may be a C1 to C8 alkyl group. For example, the alkyl group may be 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, or a tert-butyl group or a 2,2-dimethylpropyl group.

As used herein, the term "cycloalkyl group" refers to a monovalent cyclic aliphatic saturated hydrocarbon group unless otherwise defined.

The cycloalkyl group may be a C3 to C8 cycloalkyl group, for example, 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 may be a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, or a cyclohexyl group, but is not limited thereto.

As used herein, the term "aliphatic unsaturated organic group" refers to a hydrocarbon group including a bond in which a bond between carbon and a carbon atom in a molecule is a double bond, a triple bond, or a combination thereof.

The aliphatic unsaturated organic group may be a C2 to C8 aliphatic unsaturated organic group. For example, the aliphatic unsaturated organic group may be a C2 to C7 aliphatic unsaturated organic group, a C2 to C6 aliphatic unsaturated organic group, a C2 to C5 aliphatic unsaturated organic group, or a C2 to C4 aliphatic unsaturated organic group. For example, the C2 to C4 aliphatic unsaturated organic group is a vinyl group, ethynyl group, allyl group, 1-propenyl group, 1-methyl-1-propenyl group, 2-propenyl group, 2-methyl-2-propenyl group, 1- propynyl group, 1-methyl-1 propynyl group, 2-propynyl group, 2-methyl-2-propynyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, 1-butynyl group, 2 It may be a butynyl group or a 3-butynyl group.

As used herein, the term "aryl group" refers to a substituent in which all elements of a cyclic substituent have p-orbitals, and these p-orbitals form a conjugate, monocyclic or fusion ring polycyclic (ie, rings that share adjacent pairs of carbon atoms) functional groups.

As used herein, the term "alkenyl group", unless otherwise defined, is a straight-chain or branched aliphatic hydrocarbon group, and refers to an aliphatic unsaturated alkenyl group containing one or more double bonds. do.

As used herein, the term “alkynyl group” refers to a straight or branched aliphatic hydrocarbon group, unless otherwise defined, an aliphatic unsaturated alkynyl group containing one or more triple bonds. do.

Hereinafter, a composition for a semiconductor photoresist according to an embodiment will be described.

The composition for a semiconductor photoresist according to an embodiment of the present invention includes an organometallic compound and a solvent, and the organometallic compound is represented by the following formula (1).

[Formula 1]

In Formula 1,

R is 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 aliphatic unsaturated organic group containing one or more double or triple bonds, a substituted or unsubstituted is a C6 to C30 aryl group, an ethylene oxide group, a propylene oxide group, or a combination thereof,

X, Y, and Z are each independently -SR ¹ or -SC(=O)R ² ,

Wherein R ¹ is 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 a cyclic C6 to C30 aryl group, or a combination thereof,

R ² is 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 an unsubstituted C6 to C30 aryl group, or a combination thereof.

The compound represented by Formula 1 is an organotin compound, and tin strongly absorbs extreme ultraviolet light at 13.5 nm and thus has excellent sensitivity to light having high energy. R of Formula 1 may impart photosensitivity to the compound represented by Formula 1, and as R is bonded to tin to form a Sn-R bond, solubility in an organic solvent may be imparted to the organotin compound. In addition, X, Y, and Z of Formula 1 that is ^{-SR 1} or -SC(=O)R ^{2 may determine the solubility of the compound in a solvent.}

With respect to R in Formula 1, the organotin compound having the structural unit represented by Formula 1 is formed from the Sn-R bond when exposed to extreme ultraviolet light. The functional group dissociates to form radicals, The radicals thus generated are hydrolyzed and condensed by dehydration after forming a -Sn-Sn- bond to promote a crosslinking reaction between tin oxide polymers, thereby forming a semiconductor photoresist from the composition according to an embodiment.

On the other hand, the compound represented by Formula 1 includes X, Y, and Z as a ligand connected to a tin element, wherein X, Y, and Z are each independently -SR ¹ or -SC(=O)R ² can be These organic ligands are hydrolyzed and dehydrated by heat treatment under an acidic or basic catalyst or without heat treatment to form a Sn—O—Sn bond between organotin compounds, thereby deriving from the organometallic compound represented by Formula 1 above. An organotin oxide polymer is formed.

The Sn-S bond is, for example, stronger than the existing Sn-O bond, so that hydrolysis of the bond tends to be relatively difficult. Therefore, since the organometallic compound of the present invention including the Sn-S bond has high water stability, the composition for a semiconductor photoresist including the compound is easy to handle, and storage stability and solubility characteristics can be improved.

As such, since the bonding strength between Sn-S is relatively strong, the polymerization reaction between organotin compounds may proceed more slowly than, for example, polymerization between organotin compounds including Sn-O bonds. As the polymerization reaction proceeds slowly, the size of the primary particles of the organotin copolymer produced as a result of the polymerization reaction becomes relatively small, and as a result, the resolution of the composition for semiconductor photoresists including the organotin polymer can be improved.

R is, for example, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C3 to C8 cycloalkyl group, a substituted or unsubstituted C2 to C8 aliphatic unsaturated oil containing one or more double bonds or triple bonds It may be a group, a substituted or unsubstituted C6 to C20 aryl group, an ethylene oxide group, a propylene oxide group, or a combination thereof, for example, a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, tert- Butyl group, 2,2-dimethylpropyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, ethenyl group, propenyl group, butenyl group, etynyl group, propynyl group, butynyl group, phenyl group, tolyl group , a xylene group, a benzyl group, an ethylene oxide group, a propylene oxide group, or a combination thereof.

R ¹ is, for example, each independently each independently a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C3 to C8 cycloalkyl group, a substituted or unsubstituted C2 to C8 alkenyl group, a substituted or unsubstituted It may be a cyclic C2 to C8 alkynyl group, a substituted or unsubstituted C6 to C20 aryl group, or a combination thereof, for example, a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, a tert-butyl group , 2,2-dimethylpropyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, ethenyl group, propenyl group, butenyl group, ethynyl group, propynyl group, butynyl group, phenyl group, tolyl group, xylene group, benzyl group, or a combination thereof.

R ² is, for example, each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C3 to C8 cycloalkyl group, a substituted or unsubstituted C2 to C8 alkenyl group, a substituted or unsubstituted a C2 to C8 alkynyl group, a substituted or unsubstituted C6 to C20 aryl group, or a combination thereof, for example, hydrogen, a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, tert-butyl group, 2,2-dimethylpropyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, ethenyl group, propenyl group, butenyl group, ethynyl group, propynyl group, butynyl group, phenyl group, tolyl group, It may be a xylene group, a benzyl group, or a combination thereof.

The compound represented by Formula 1 may include a compound represented by Formula 2 below, a compound represented by Formula 3, a compound represented by Formula 4, a compound represented by Formula 5, or a combination thereof.

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

In Formulas 2 to 5,

R is as defined in Formula 1 above,

R ^a , R ^b , R ^c , R ⁱ , R ^k , and R ¹ are each independently the same as defined for ^{R 1 in Formula 1 above,}

R ^d , R ^e , R ^f , R ^g , R ^h , and R ^j are each independently the same as defined for ^{R 2 in Formula 1 above.}

The invention according to one embodiment provides a composition for a semiconductor photoresist comprising a compound having a substituent connected to each of three sulfur atoms on a tin atom as shown in Chemical Formulas 1 to 5, wherein the composition for such a photoresist is provided. The composition has relatively improved resolution and excellent pattern formation, so that the pattern does not collapse even if it has a high aspect ratio.

In the semiconductor photoresist composition according to an embodiment, the organometallic compound represented by Formula 1 is 1 wt% to 30 wt%, for example, 1 wt% to 25 wt%, based on the total weight of the composition For example, 1% to 20% by weight, for example, 1% to 15% by weight, for example, 1% to 10% by weight, for example, 1% to 5% by weight to be included in the content of may, but are not limited to these. When the organometallic compound represented by Formula 1 is included in an amount within the above range, storage stability and solubility characteristics of the composition for semiconductor photoresists are improved, thin film formation is facilitated, and resolution characteristics are improved.

The solvent included in the semiconductor photoresist composition according to the embodiment may be an organic solvent, for example, aromatic compounds (eg, xylene, toluene), alcohols (eg, 4-methyl-2-pentane). ol, 4-methyl-2-propanol, 1-butanol, methanol, isopropyl alcohol, 1-propanol, propylene glycol monomethyl ether), ethers (eg anisole, tetrahydrofuran), esters (n -Butyl acetate, propylene glycol monomethyl ether acetate, ethyl acetate, ethyl lactate), ketones (eg, methyl ethyl ketone, 2-heptanone), mixtures thereof, and the like may be included, but are not limited thereto. .

In one embodiment, the semiconductor photoresist composition may further include a resin in addition to the organometallic compound and the solvent.

The resin may be a phenolic resin including at least one aromatic moiety listed in Group 1 below.

[Group 1]

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

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

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

On the other hand, the composition for a semiconductor photoresist according to an embodiment is preferably made of the aforementioned organometallic compound, a solvent, and a resin. However, the composition for a semiconductor photoresist according to the above-described embodiment may further include an additive in some cases. Examples of the additive include a surfactant, a crosslinking agent, a leveling agent, or a combination thereof.

The surfactant may be, for example, an alkylbenzenesulfonic acid salt, an alkylpyridinium salt, polyethylene glycol, a quaternary ammonium salt, or a combination thereof, but is not limited thereto.

The cross-linking agent may include, for example, a melamine-based cross-linking agent, a substituted urea-based cross-linking agent, or a polymer-based cross-linking agent, but is not limited thereto. Crosslinking agents having at least two crosslinking substituents, for example, methoxymethylated glycouryl, butoxymethylated glycouryl, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxymethylated benzoguanamine , methoxymethylated urea, butoxymethylated urea, or methoxymethylated thiourea may be used.

The leveling agent is for improving coating flatness during printing, and a known leveling agent available in a commercial manner may be used.

The amount of these additives used may be easily adjusted according to desired physical properties or may be omitted.

In addition, the composition for a semiconductor photoresist may further use a silane coupling agent as an additive to improve adhesion to the substrate (eg, to improve adhesion of the composition for semiconductor photoresist to the substrate), and as an adhesion promoter. The silane coupling agent is, for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyl trichlorosilane, vinyltris(β-methoxyethoxy)silane; or 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, p-styryl trimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldi ethoxysilane; A silane compound containing a carbon-carbon unsaturated bond such as trimethoxy[3-(phenylamino)propyl]silane may be used, but the present invention is not limited thereto.

In the composition for a semiconductor photoresist, pattern collapse may not occur even when a pattern having a high aspect ratio is formed. Thus, for example, a micropattern having a width of 5 nm to 100 nm, for example a micropattern having a width of 5 nm to 80 nm, for example, a micropattern having a width of 5 nm to 70 nm, e.g. For example, a fine pattern having a width of 5 nm to 50 nm, for example, a fine pattern having a width of 5 nm to 40 nm, for example, a fine pattern having a width of 5 nm to 30 nm, 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 to form a fine pattern having a width of 5 nm to 20 nm , for example, a photoresist process using light with a wavelength of 5 nm to 80 nm, for example a photoresist process using light with a wavelength of 5 nm to 50 nm, for example, a photoresist process using light with a wavelength of 5 nm to 30 nm It can be used in a photoresist process using light, for example, a photoresist process using light having a wavelength of 5 nm to 20 nm. Therefore, using the composition for a semiconductor photoresist according to an embodiment, extreme ultraviolet lithography using an EUV light source having a wavelength of about 13.5 nm may be implemented.

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

According to another exemplary embodiment, a method for forming a pattern includes forming an etch target film on a substrate, applying the above-described composition for a semiconductor photoresist on the etch target film to form a photoresist film, patterning the photoresist film to form a photoresist pattern and etching the etch target layer using the photoresist pattern as an etch mask.

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

Referring to FIG. 1 , first, an object to be etched is prepared. An example of the object to be etched may be the thin film 102 formed on the semiconductor substrate 100 . Hereinafter, only the case where the object to be etched is the thin film 102 will be described. The surface of the thin film 102 is cleaned to remove contaminants and the like 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.

Then, a composition for forming a resist underlayer film for forming the resist underlayer film 104 on the surface of the cleaned thin film 102 is coated 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, may be used.

The resist underlayer coating process may be omitted, and the case of coating the resist underlayer film will be described below.

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

The resist underlayer film 104 is formed between the substrate 100 and the photoresist film 106, so that radiation reflected from the interface between the substrate 100 and the photoresist film 106 or from an interlayer hardmask is not intended. In the case of scattering to a non-photoresist region, it is possible to prevent non-uniformity of photoresist linewidth and interruption of pattern formation.

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

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

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

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

Referring to FIG. 3 , the photoresist layer 106 is selectively exposed.

For example, examples of light that can be used in the exposure process include not only light having a short wavelength such as an activating radiation i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), etc. , light having a high energy wavelength such as EUV (Extreme Ultraviolet; wavelength 13.5 nm), E-Beam (electron beam), and the like.

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

The exposed region 106a of the photoresist film 106 has a solubility different from that of the unexposed region 106b of the photoresist film 106 as a polymer is formed by a crosslinking reaction such as condensation between organometallic compounds. .

Next, a second baking process is performed on the substrate 100 . The second baking process may be performed at a temperature of about 90 °C to about 200 °C. By performing the second baking process, the exposed region 106a of the photoresist layer 106 becomes difficult to dissolve in a developer.

4 shows a photoresist pattern 108 formed by dissolving and removing the photoresist film 106b corresponding to the unexposed region using a developer. Specifically, the photoresist pattern corresponding to the negative tone image ( 108) is completed.

As described above, the developer used in the pattern forming method according to the exemplary embodiment may be an organic solvent. As an example of the organic solvent used in the pattern forming method according to the embodiment, ketones such as methyl ethyl ketone, acetone, cyclohexanone, 2-haptanone, 4-methyl-2-propanol, 1-butanol, isopropanol, Alcohols such as 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 these can be a combination of

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

As described above, not only light having a wavelength such as i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), but also EUV (Extreme UltraViolet; wavelength 13.5 nm), The photoresist pattern 108 formed by exposure to light having high energy, such as an E-beam (electron beam), may have a width of 5 nm to 100 nm. For example, the photoresist pattern 108 may be 5 nm to 90 nm, 5 nm to 80 nm, 5 nm to 70 nm, 5 nm to 60 nm, 10 nm to 50 nm, 10 nm to 40 nm, 10 nm to 30 nm, and may be formed to a width of 10 nm to 20 nm.

On the other hand, the photoresist pattern 108 has a half-pitch of about 50 nm or less, for example 40 nm or less, for example 30 nm or less, for example 25 nm or less, and about 10 nm or less, It may have a pitch having a linewidth roughness of about 5 nm or less.

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

Referring to FIG. 5 , the exposed thin film 102 is etched by applying the photoresist pattern 108 as an etching mask. As a result, the thin film is formed as a thin film pattern 114 .

The thin film 102 may be etched, for example, by dry etching using an etching gas, and the etching gas may be, for example, CHF ₃ , CF ₄ , Cl ₂ , BCl _{3 ,} or a mixture thereof.

In the exposure process performed above, 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, the photoresist pattern 108 may have a width of 5 nm to 100 nm. For example, the thin film pattern 114 formed by the exposure process performed using the EUV light source may be 5 nm to 90 nm, 5 nm to 80 nm, 5 nm to 70 nm, 5 like the photoresist pattern 108 . It may have a width of nm to 60 nm, 10 nm to 50 nm, 10 nm to 40 nm, 10 nm to 30 nm, 10 nm to 20 nm, and more specifically, may be formed to a width of 20 nm or less.

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

Example

Synthesis Example 1

_{Dissolve Ph 3} SnCl (20 g, 51.9 mmol) in 100 ml of anhydrous tetrahydrofuran (THF) in a 250 mL two-necked round-bottom flask, and lower the temperature to 0 °C in an ice bath. Then, butyl magnesium chloride (BuMgCl) 1M THF solution (62.3 mmol) is slowly added dropwise. After completion of the dropwise addition, the mixture was stirred at 25° C. for 12 hours to obtain a compound represented by the following formula (6).

[Formula 6]

Synthesis Example 2

Except for using isopropyl magnesium chloride (iPrMgCl) 2M THF solution (62.3 mmol) instead of butyl magnesium chloride (BuMgCl) 1 M THF solution in Synthesis Example 1, it was synthesized in the same manner as in Synthesis Example 1 and obtained by the following Chemical Formula 7 The indicated compound is obtained.

[Formula 7]

Synthesis Example 3

Except for using 1 M THF solution of neopentyl magnesium chloride (62.3 mmol) instead of 1 M THF solution of butyl magnesium chloride (BuMgCl) in Synthesis Example 1, it was synthesized in the same manner as in Synthesis Example 1 and represented by Formula 8 get the compound.

[Formula 8]

Synthesis Example 4

The compound of Formula 6 of Synthesis Example 1 (10 g, 24.6 mmol) was dissolved in 50 mL of CH ₂ Cl ₂ , and a 2 M HCl diethyl ether solution (3 equivalents, 73.7 mmol) was added at -78°C to 30 Add dropwise slowly over a minute. After stirring at 25 °C for 12 hours, the solvent is concentrated and vacuum distilled to obtain a compound represented by the following formula (9).

[Formula 9]

Synthesis Example 5

A compound represented by the following formula (10) was obtained by synthesizing in the same manner as in Synthesis Example 4, except that the compound of Formula 7 of Synthesis Example 2 was used instead of using the compound of Formula 6 of Synthesis Example 1.

[Formula 10]

Synthesis Example 6

A compound represented by the following formula (11) was obtained by synthesizing in the same manner as in Synthesis Example 4, except that the compound of Formula 8 of Synthesis Example 3 was used instead of using the compound of Formula 6 of Synthesis Example 1.

[Formula 11]

Synthesis Example 7

To the compound of Formula 6 (10 g, 25.6 mmol) of Synthesis Example 1, 25 mL of thioacetic acid was slowly added dropwise at 25° C., and then heated to reflux for 12 hours. After raising the temperature to 25 °C, thioacetic acid is vacuum distilled to obtain a compound represented by the following formula (12).

[Formula 12]

Synthesis Example 8

To the compound of Formula 7 (10 g, 25.4 mmol) of Synthesis Example 2, 25 mL of thioacetic acid was slowly added dropwise at 25° C., and then heated to reflux at 100° C. for 12 hours. After raising the temperature to 25 °C, thioacetic acid is vacuum distilled to obtain a compound represented by the following formula (13).

[Formula 13]

Synthesis Example 9

To the compound of Formula 8 (10 g, 23.7 mmol) in Synthesis Example 3, 25 mL of thioacetic acid was slowly added dropwise at 25 °C, and then heated to reflux at 110 °C for 12 hours. After raising the temperature to 25 °C, thioacetic acid is vacuum distilled to obtain a compound represented by the following formula (14).

[Formula 14]

Synthesis Example 10

30 mL of anhydrous pentane was added to the compound of Formula 9 (10 g, 35.4 mmol) of Synthesis Example 4, and the temperature was lowered to 0 °C. Diethylamine (7.8 g, 106.3 mmol) was slowly added dropwise, and then t-butylthiol (9.6 g, 106.3 mmol) was added, followed by stirring at 25° C. for 1 hour. Upon completion of the reaction, the mixture is filtered, concentrated and dried under vacuum to obtain a compound represented by the following formula (15).

[Formula 15]

Synthesis Example 11

30 mL of anhydrous pentane was added to the compound of Formula 10 (10 g, 37.3 mmol) of Synthesis Example 5, and the temperature was lowered to 0 °C. Diethylamine (8.2 g, 111.9 mmol) was slowly added dropwise, and then allyl mercaptan (8.3 g, 111.9 mmol) was added thereto, followed by stirring at 25 °C for 1 hour. When the reaction is completed, the mixture is filtered, concentrated and dried under vacuum to obtain a compound represented by the following formula (16).

[Formula 16]

Synthesis Example 12

30 mL of anhydrous pentane was added to the compound of Formula 11 (10 g, 18.7 mmol) of Synthesis Example 6, and the temperature was lowered to 0 °C. Diethylamine (7.4 g, 101.3 mmol) was slowly added dropwise, and then thiophenol (11.1 g, 101.3 mmol) was added, followed by stirring at 25 °C for 1 hour. When the reaction is completed, the mixture is filtered, concentrated and dried under vacuum to obtain a compound represented by the following formula (17).

[Formula 17]

Comparative Synthesis Example 1

After dissolving dibutyltin dichloride (10 g, 33 mmol) in 30 mL of ether, 70 mL of a 1 M aqueous sodium hydroxide (NaOH) solution is added, followed by stirring for 1 hour. After stirring, the resulting solid is filtered, washed three times with 25 mL of deionized water, and then dried under reduced pressure at 100° C. to obtain an organometallic compound having a weight average molecular weight of 1,500 g/mol represented by the following Chemical Formula 18.

[Formula 18]

Examples 1 to 6

Compounds 12 to 17 obtained in Synthesis Examples 7 to 12 were dissolved in PGMEA (propylene glycol monomethyl ether acetate) at a concentration of 3 wt%, and filtered with a 0.1 μm PTFE (polytetrafluoroethylene) syringe filter. A photoresist composition according to Examples 1 to 6 was prepared.

A circular silicon wafer having a diameter of 4 inches having a native-oxide surface was used as a substrate for thin film coating, and treated for 10 minutes in a UV ozone cleaning system before coating the thin film. The semiconductor photoresist composition according to Examples 1 to 6 was spin-coated at 1500 rpm for 30 seconds on the treated substrate, and baked at 100° C. for 120 seconds (post-apply bake, PAB). A photoresist thin film is formed.

After coating and baking, the thickness of the film was measured through ellipsometry, and the measured thickness was about 20 nm.

Comparative Example 1

In the same manner as in Example 1, except that compound 18 according to Comparative Synthesis Example 1 was dissolved in 4-methyl-2-pentanol at a concentration of 1 wt% and used, Comparative Example The composition for a semiconductor photoresist according to 1 and a photoresist thin film comprising the same were prepared. The thickness of the film after coating and baking was about 20 nm.

Evaluation 1: Resolution

The films according to Examples 1 to 6 and Comparative Example 1 prepared by the above coating method on a circular silicon wafer were exposed to extreme ultraviolet light to form a line/space pattern of 12 to 100 nm by varying energy and focus. . After exposure, calcined at 180°C for 120 seconds, then immersed in a Petri dish containing 2-heptanone for 60 seconds, taken out, and washed with the same solvent for 10 seconds. Finally, after firing at 150° C. for 5 minutes, a pattern image is obtained by scanning electron microscopy (SEM). The highest resolution identified from the SEM image is shown in Table 1 below.

Evaluation 2: Solubility, storage stability

For the photoresist compositions for semiconductors according to Examples 1 to 6 and Comparative Example 1, solubility and storage stability of the compositions were evaluated according to the following criteria, and are shown together in Table 1 below.

[solubility]

The degree of solubility was evaluated in the following three steps based on when the compounds of Formulas 12 to 17 of Synthesis Examples 7 to 12 and Formula 18 of Comparative Synthesis Example 1 were dissolved in xylene at the following weights.

○: 3 wt% or more dissolved in xylene

△: dissolved in xylene at 1 wt% or more and less than 3 wt%

X: less than 1% by weight dissolved in xylene

[Storage Stability]

After visually observing the degree of precipitation occurring when left for a specific period at 25 °C (room temperature) conditions, it was set as a standard that it can be stored and evaluated in the following three steps.

○: Can be stored for more than 1 month

△: Can be stored for 1 week to less than 1 month

X: Can be stored for less than 1 week

Resolution (nm) (HP ^* ) Solubility storage stability Example 1 16 ○ ○ Example 2 14 ○ ○ Example 3 16 ○ ○ Example 4 18 ○ ○ Example 5 16 ○ ○ Example 6 18 ○ ○ Comparative Example 1 26 X -

(* HP: based on half pitch) From the results in Table 1, the photoresist compositions for semiconductors according to Examples 1 to 6 exhibit superior solubility and storage stability compared to Comparative Example 1, and the pattern formed using the same has superior resolution compared to Comparative Example It can be seen that indicates On the other hand, since the semiconductor photoresist composition according to Comparative Example 1 has poor solubility in a xylene solvent, it can be confirmed that it is practically difficult to evaluate the storage stability of the composition.

In the foregoing, specific embodiments of the present invention have been described and shown, but it is common knowledge 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. It is self-evident to those who have Accordingly, such modifications or variations should not be individually understood from the technical spirit or point of view of the present invention, and modified embodiments should be considered to belong to the claims of the present invention.

100: substrate 102: thin film
104: resist underlayer film 106: photoresist film
106a: exposed area 106b: unexposed area
108: photoresist pattern 112: organic film pattern
114: thin film pattern

Claims (10)

A composition for a semiconductor photoresist comprising an organometallic compound represented by the following Chemical Formula 1 and a solvent:
[Formula 1]

In Formula 1,
R is 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 aliphatic unsaturated organic group containing one or more double or triple bonds, a substituted or unsubstituted is a C6 to C30 aryl group, an ethylene oxide group, a propylene oxide group, or a combination thereof,
X, Y, and Z are each independently -SR ¹ or -SC(=O)R ² ,
Wherein R ¹ is 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 a cyclic C6 to C30 aryl group, or a combination thereof,
R ² is 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 an unsubstituted C6 to C30 aryl group, or a combination thereof.
In claim 1,
R is a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C3 to C8 cycloalkyl group, a substituted or unsubstituted C2 to C8 aliphatic unsaturated organic group containing one or more double or triple bonds, a substituted or unsubstituted is a C6 to C20 aryl group, an ethylene oxide group, a propylene oxide group, or a combination thereof,
R ¹ is a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C3 to C8 cycloalkyl group, a substituted or unsubstituted C2 to C8 alkenyl group, a substituted or unsubstituted C2 to C8 alkynyl group, a substituted or unsubstituted a C6 to C20 aryl group, or a combination thereof,
R ² is hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C3 to C8 cycloalkyl group, a substituted or unsubstituted C2 to C8 alkenyl group, a substituted or unsubstituted C2 to C8 alkynyl group, a substituted or A composition for a semiconductor photoresist comprising an unsubstituted C6 to C20 aryl group, or a combination thereof.
In claim 1,
R is a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, a tert-butyl group, a 2,2-dimethylpropyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, an ethenyl group, a propenyl group , butenyl group, ethynyl group, propynyl group, butynyl group, phenyl group, tolyl group, xylene group, benzyl group, ethylene oxide group, propylene oxide group, or a combination thereof,
R ¹ is a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, a tert-butyl group, a 2,2-dimethylpropyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, an ethenyl group, a pro a phenyl group, a butenyl group, an ethynyl group, a propynyl group, a butynyl group, a phenyl group, a tolyl group, a xylene group, a benzyl group, or a combination thereof;
R ² is hydrogen, methyl group, ethyl group, propyl group, butyl group, isopropyl group, tert-butyl group, 2,2-dimethylpropyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, ethenyl group , a propenyl group, a butenyl group, an ethynyl group, a propynyl group, a butynyl group, a phenyl group, a tolyl group, a xylene group, a benzyl group, or a combination thereof.
In claim 1,
The compound represented by Formula 1 is a compound represented by Formula 2 below, a compound represented by Formula 3, a compound represented by Formula 4, a compound represented by Formula 5, or a composition for a semiconductor photoresist comprising a combination thereof:
[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

In Formula 2, Formula 3, Formula 4, and Formula 5,
R is 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 aliphatic unsaturated organic group containing one or more double or triple bonds, a substituted or unsubstituted is a C6 to C30 aryl group, an ethylene oxide group, a propylene oxide group, or a combination thereof,
R ^a , R ^b , R ^c , R ⁱ , R ^k , and R ¹ are each independently a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to a 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;
R ^d , ^Re , R ^f , R ^g , R ^h , and R ^j 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 a 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 claim 1,
A composition for a semiconductor photoresist comprising 1 to 30% by weight of the organometallic compound represented by Formula 1, based on 100% by weight of the composition for a semiconductor photoresist.
In claim 1,
The composition is a composition for a semiconductor photoresist further comprising an additive of a surfactant, a crosslinking agent, a leveling agent, or a combination thereof.
forming an etch target layer on the substrate;
forming a photoresist layer by applying the composition for a semiconductor photoresist according to any one of claims 1 to 6 on the etching target layer;
forming a photoresist pattern by patterning the photoresist layer; and
and etching the etch target layer using the photoresist pattern as an etch mask.
In claim 7,
The step of forming the photoresist pattern is a pattern forming method using light having a wavelength of 5 nm to 150 nm.
In claim 7,
The method further comprising the step of providing a resist underlayer film formed between the substrate and the photoresist film.
In claim 7,
The photoresist pattern is a pattern forming method having a width of 5 nm to 100 nm.

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