KR20210060220A - Resist underlayer composition, and method of forming patterns using the composition - Google Patents

Abstract

Provided are a composition for a resist underlayer including a polymer having a structural unit represented by chemical formula 1 and a solvent, and a pattern forming method using the composition for a resist underlayer, wherein in chemical formula 1, each substituent is as defined in the specification.

Description

Composition for a resist underlayer film and a pattern forming method using the same {RESIST UNDERLAYER COMPOSITION, AND METHOD OF FORMING PATTERNS USING THE COMPOSITION}

The present description relates to a composition for a resist underlayer film, and a pattern forming method using the same.

Recently, the semiconductor industry is developing from a pattern of several hundred nanometers to an ultra-fine technology having a pattern of several to tens of nanometers. Effective lithographic techniques are essential to realize such ultra-fine technology.

The exposure process performed in the photoresist pattern formation step is one of the important factors for obtaining a high-resolution photoresist image.

As semiconductor patterns gradually become finer, the active radiation used for exposure of photoresist is also being expanded to short wavelengths such as i-line (365 nm), KrF excimer laser (wavelength 248 nm), and ArF excimer laser (wavelength 193 nm). There is an increasing need for a resist underlayer film that can be applied to a patterning process for forming an ultra-fine pattern in the 10 nm range using a (Extreme Ultraviolet) light source.

In particular, the resist underlayer film must have a high etch selectivity with the photoresist, chemical resistance to the solvent used in the process after heat curing is performed during the process, and excellent adhesion to the resist film is required. However, many reviews are being made to solve this problem.

It provides a composition for a resist underlayer film that can exhibit improved light absorption efficiency for EUV, and thereby improve the sensitivity of a photoresist.

Another embodiment provides a pattern forming method using the resist underlayer composition.

According to one embodiment, there is provided a composition for a resist underlayer film comprising a polymer including a structural unit represented by the following Formula 1, and a solvent.

[Formula 1]

In Formula 1,

A is a divalent nitrogen-containing heteroaromatic ring group,

L ₁ , L ₂ , L ₃ are each independently a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C1 to C10 heteroalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or An unsubstituted C2 to C20 heterocycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C1 to C10 heteroarylene group,

X ₁ , X ₂ are each independently selected from halogen groups (-F, -Cl, -Br, -I),

Z ₁ , Z ₂ are each independently oxygen, sulfur, or -N(R ^a-- )- (however, R ^a is hydrogen, deuterium, a halogen group (-F, -Cl, -Br, -I), A substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, or a substituted or unsubstituted C6 to C20 aryl group), and * is a connection point.

According to another embodiment, forming an etching target layer on a substrate, forming a resist underlayer layer by applying the composition for a resist underlayer film according to an embodiment on the etching target layer, forming a photoresist pattern on the resist underlayer layer And sequentially etching the resist underlayer layer and the etching target layer using an etching mask for the photoresist pattern.

The composition for a resist underlayer film according to an exemplary embodiment may exhibit improved light absorption efficiency for EUV, thereby improving sensitivity of a photoresist.

1 to 5 are cross-sectional views illustrating a method of forming a pattern using a composition for a resist underlayer film according to an exemplary embodiment.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art may easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

In the drawings, the thickness is enlarged in order to clearly express various layers and regions, and the same reference numerals are attached to similar parts throughout the specification. When a part of a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the case where the other part is "directly above", but also the case where there is another part in the middle. Conversely, when one part is "directly above" another part, it means that there is no other part in the middle.

Unless otherwise defined herein, the term'substituted' means that the hydrogen atom in the compound is a halogen group (-F, -Br, -Cl, or -I), a hydroxy group, an alkoxy group, a nitro group, a cyano group, an amino group, An azido group, an amidino group, a hydrazino group, a hydrazono group, a carbonyl group, a carbamyl group, a thiol group, an ester group, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, phosphoric acid or a salt thereof, a vinyl group, a C1 to C20 alkyl group, C2 to C20 alkenyl group, C2 to C20 alkynyl group, C6 to C30 aryl group, C7 to C30 arylalkyl group, C6 to C30 allyl group, C1 to C30 alkoxy group, C1 to C20 heteroalkyl group, C3 to C20 heteroarylalkyl group, C3 To C30 cycloalkyl group, C3 to C15 cycloalkenyl group, C6 to C15 cycloalkynyl group, C3 to C30 heterocycloalkyl group, and a combination thereof.

In addition, unless otherwise defined in the specification,'hetero' means containing 1 to 3 heteroatoms selected from N, O, S, and P.

Unless otherwise specified in the specification, the weight average molecular weight is measured by dissolving a powder sample in tetrahydrofuran (THF) and then using Agilent Technologies' 1200 series Gel Permeation Chromatography (GPC) (column is Shodex Company LF-804, standard sample is Shodex company polystyrene).

Hereinafter, a composition for a resist underlayer film according to an embodiment will be described.

The composition for a resist underlayer film according to an embodiment includes a polymer including a structural unit represented by Formula 1 below, and a solvent.

[Formula 1]

In Formula 1,

A is a divalent nitrogen-containing heteroaromatic ring group,

L ₁ , L ₂ , L ₃ are each independently a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C1 to C10 heteroalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or An unsubstituted C2 to C20 heterocycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C1 to C10 heteroarylene group,

X ₁ , X ₂ are each independently selected from halogen groups (-F, -Cl, -Br, -I),

Z ₁ , Z ₂ are each independently oxygen, sulfur, or -N(R ^a-- )- (however, R ^a is hydrogen, deuterium, a halogen group (-F, -Cl, -Br, -I), It may be a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, or a substituted or unsubstituted C6 to C20 aryl group).

* Is a connection point where two or more structural units are connected to each other.

In one embodiment, as a specific example of the divalent nitrogen-containing heteroaromatic ring group, the following Formula A-1, Formula A-2, or a combination thereof may be mentioned.

[Formula A-1]

[Formula A-2]

In Formula A-1 and Formula A-2,

R ₁ , R ₂ are each independently hydrogen, deuterium, a halogen group (-F, -Cl, -Br, -I), a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group , A substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted A C2 to C20 heteroalkenyl group, a substituted or unsubstituted C3 to C20 heterocycloalkyl group, or a substituted or unsubstituted C6 to C20 heteroaryl group,

* Is a linking point with another adjacent divalent nitrogen-containing heteroaromatic ring group, and/or other linking groups (L ₁ , L _{2 ).}

In one embodiment _{, each of L 1} , L ₂ , and L ₃ may be the same as or different from each other, and any two of the three may be the same.

In one embodiment, L ₁ , L ₂ , L ₃ are each independently a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C1 to C10 heteroalkylene group, a substituted or unsubstituted C3 to C20 cyclo It may be an alkylene group, or a substituted or unsubstituted C2 to C20 heterocycloalkylene group. In one embodiment, L ₁ , L ₂ , L ₃ may each independently be a substituted or unsubstituted C1 to C10 alkylene group, or a substituted or unsubstituted C1 to C10 heteroalkylene group.

In one embodiment, X ₁ and X ₂ may each be the same as or different from each other. In one embodiment, X ₁ and X ₂ may be the same halogen group.

In one embodiment, each of Z ₁ and Z ₂ may be the same as or different from each other. In one embodiment, Z ₁ and Z ₂ may be the same as each other. For example, if Z ₁ is oxygen, then Z ₂ may also be oxygen.

Specifically, the structural unit represented by Formula 1 may include a structural unit represented by Formula 1-1 or Formula 1-2 below.

[Formula 1-1]

[Formula 1-2]

In Formula 1-1 and Formula 1-2,

L ₁₁ , L ₁₂ , L ₁₃ , L ₂₁ , L ₂₂ , L ₂₃ are each independently a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C1 to C10 heteroalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C2 to C20 heterocycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C1 to C10 heteroarylene group,

R ₁₁ and R ₂₁ are each independently hydrogen, deuterium, a halogen group (-F, -Cl, -Br, -I), a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group , A substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted A C2 to C20 heteroalkenyl group, a substituted or unsubstituted C3 to C20 heterocycloalkyl group, or a substituted or unsubstituted C6 to C20 heteroaryl group,

X is selected from halogen groups (-F, -Cl, -Br, -I),

Z is oxygen, sulfur, or -N(R ^a-- )-, or -N(R ^a-- )- (However, R ^a is hydrogen, deuterium, halogen group (-F, -Cl, -Br,- I), a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, or a substituted or unsubstituted C6 to C20 aryl group),

n and m are each independently an integer of 2 to 100.

Meanwhile, the polymer including the structural unit may include one or more of the structural units represented by the following Chemical Formulas 2 to 8.

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

For example, when the polymer constituting the resist underlayer film composition contains an isocyanurate-based compound in which a halogen group is introduced into the side chain, for example, "-C (-halogen group) -C- (oxygen, nitrogen) is included in the main chain. , Or NR ^a )-" When an isocyanurate-based compound having a chemical bond is included, the isocyanurate-based compound can improve the absorption efficiency of the exposure light source when the resist underlayer composition is exposed.

In one embodiment, the polymer containing an isocyanurate-based compound in which a halogen group is introduced into the side chain has an effect of increasing the film density of the resist underlayer composition. The resist underlayer composition according to an embodiment may exhibit improved adhesion to the upper photoresist due to the increased film density as described above, and may exhibit improved chemical resistance against solvents used during the coating process of the upper photoresist. . Therefore, if the high-density resist underlayer composition according to an embodiment is used, a resist underlayer film having improved adhesion and chemical resistance and a reduced thickness can be formed, and through this, a faster etching effect than the upper photoresist can be expected.

In one embodiment, when the resist underlayer film is formed by using the resist underlayer film composition, secondary electrons may additionally be generated during the photo process. The additionally generated secondary electrons affect the photoresist during the photo process, thereby maximizing the acid generation efficiency. Accordingly, the sensitivity of the photoresist can be improved by improving the photo process speed of the photoresist.

In addition, the polymer containing the isocyanurate-based compound has excellent solubility in organic solvents such as propylene glycol methyl ether (PGME), even if it is polymerized with a relatively high molecular weight. Accordingly, the resist underlayer composition may exhibit excellent coating properties and strip resistance due to excellent solubility with the organic solvent.

In addition, since the polymer is stable against an organic solvent and heat, when a resist underlayer film is formed using a composition for a resist underlayer film containing the polymer, it may be peeled off by a solvent or heat while performing a process for forming a photoresist pattern. It is possible to minimize the generation of by-products due to the generation of chemical substances, and the thickness loss due to the upper photoresist solvent can also be minimized.

Meanwhile, the polymer may contain sulfur (S) in its main chain. In this case, a relatively high refractive index can be implemented, and a faster etching rate can be obtained.

In addition, the polymer has excellent solubility, so it is possible to form a resist underlayer film having excellent coating uniformity and strong resistance to strips. When the polymer is used as a material for a resist underlayer film, during the baking process A uniform thin film can be formed without the formation of pin-holes and voids or deterioration in thickness distribution, and excellent gap-fill and planarization properties are provided when there is a step difference in the lower substrate (or film) or when a pattern is formed. can do.

The composition for a resist underlayer film according to an embodiment has excellent coating uniformity, excellent stability, can implement a high refractive index, and has a high etching rate, and thus can be applied to an EUV (Extreme Ultraviolet) lithography process. The EUV lithography process is a lithography technique using light of a very short wavelength such as 10 nm to 20 nm, for example, 13.5 nm, and is a process capable of forming an ultrafine pattern having a width of 20 nm or less.

Meanwhile, the polymer may have a weight average molecular weight (Mw) of 1,000 to 100,000. More specifically, the polymer may have a weight average molecular weight of 1,000 to 50,000, or 1,000 to 30,000. By having a weight average molecular weight in the above range, it can be optimized by adjusting the carbon content and solubility in a solvent of the composition for a resist underlayer film containing the polymer.

The solvent is not particularly limited as long as it has sufficient solubility or dispersibility in the polymer, such as propylene glycol, propylene glycol diacetate, methoxy propanediol, diethylene glycol, diethylene glycol butyl ether, tri(ethylene glycol) mono Methyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, ethyl lactate, gamma-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, methylpyrrolidone , Methylpyrrolidinone, acetylacetone, and ethyl 3-ethoxypropionate.

The polymer may be included in an amount of 0.1 to 50% by weight, 0.1 to 30% by weight, or 0.1 to 15% by weight based on the total content of the composition for the resist underlayer film. By being included in the above range, the thickness, surface roughness, and degree of planarization of the resist underlayer film can be adjusted.

In addition, the composition for the resist underlayer film may further include at least one other polymer among acrylic resins, epoxy resins, novolac resins, glucoluryl resins, and melamine resins, in addition to the polymer described above, but is not limited thereto. .

The composition for the resist underlayer film may further include an additive of a surfactant, a thermal acid generator, a plasticizer, or a combination thereof.

The surfactant may be, for example, an alkylbenzene sulfonic acid salt, an alkylpyridinium salt, a polyethylene glycol, a quaternary ammonium salt, or the like, but is not limited thereto.

The thermal acid generator is an acidic compound such as p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonic acid, salicylic acid, sulfosalicylic acid, citric acid, benzoic acid, hydroxybenzoic acid, naphthalenecarboxylic acid or/and benzointosyl Rate, 2-nitrobenzyltosylate, and other organic fonate alkyl esters may be used, but are not limited thereto.

The additive may be included in an amount of 0.001 to 40 parts by weight based on 100 parts by weight of the resist underlayer composition. By including it in the above range, the solubility can be improved without changing the optical properties of the composition for a resist underlayer film.

According to another embodiment, a resist underlayer film prepared using the above-described composition for a resist underlayer film is provided. The resist underlayer film may be formed by coating the above-described resist underlayer film composition on a substrate, for example, and then curing through a heat treatment process.

Hereinafter, a method of forming a pattern using the above-described composition for a resist underlayer film will be described with reference to FIGS. 1 to 5.

1 to 5 are cross-sectional views illustrating a method of forming a pattern using the composition for a resist underlayer film 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 a 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 is pre-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.

Subsequently, a composition for a resist underlayer film including a polymer and a solvent having moieties represented by Chemical Formulas 1 and 2 is coated on the surface of the cleaned thin film 102 by applying a spin coating method.

에서 수행하고, 예컨대 100 내지 300

에서 수행할 수 있다. 보다 구체적인 레지스트 하층막용 조성물에 대한 설명은 위에서 상세히 설명하였기 때문에 중복을 피하기 위해 생략한다.Thereafter, drying and baking processes are performed to form a resist underlayer layer 104 on the thin film. The baking treatment is 100 to 500

Carried out in, for example 100 to 300

Can be done in Since a more detailed description of the composition for a resist underlayer film has been described in detail above, it will be omitted to avoid duplication.

Referring to FIG. 2, a photoresist layer 106 is formed by coating a photoresist on the resist underlayer layer 104.

Examples of the photoresist include a positive photoresist containing a naphthoquinone diazide compound and a novolac resin, an acid generator capable of dissociating an acid by exposure, and decomposition in the presence of an acid to increase solubility in an aqueous alkaline solution. Quantification of chemically amplified type photoresist containing alkali-soluble resin, chemically amplified type containing alkali-soluble resin with a group capable of imparting a resin that increases solubility in aqueous alkali solution by decomposition in the presence of an acid generator and acid Type photoresist, etc. are mentioned.

내지 120

의 온도에서 수행할 수 있다.Subsequently, a first baking process of heating the substrate 100 on which the photoresist layer 106 is formed is performed. The first baking process is 90

To 120

It can be carried out at a temperature of.

3, the photoresist film 106 is selectively exposed.

When an exposure process for exposing the photoresist layer 106 is described as an example, an exposure mask having a predetermined pattern is positioned on a mask stage of an exposure apparatus, and the exposure mask ( 110). Subsequently, by irradiating light to the mask 110, a predetermined portion of the photoresist film 106 formed on the substrate 100 selectively reacts with the light transmitted through the exposure mask.

As an example, examples of light that can be used in the exposure process include short-wavelength light such as an activated irradiation i-line having a wavelength of 365 nm, a KrF excimer laser having a wavelength of 248 nm, and an ArF excimer laser having a wavelength of 193 nm. In addition, EUV (Extreme Ultraviolet) having a wavelength of 13.5 nm corresponding to extreme ultraviolet light may be mentioned.

The photoresist film 106a at the exposed portion has a relatively hydrophilicity compared to the photoresist film 106b at the non-exposed portion. Accordingly, the photoresist film of the exposed portion 106a and the non-exposed portion 106b has different solubility.

Subsequently, a second baking process is performed on the substrate 100. The second baking process may be performed at a temperature of 90°C to 150°C. By performing the second baking process, the photoresist film corresponding to the exposed area is easily dissolved in a specific solvent.

Referring to FIG. 4, a photoresist pattern 108 is formed by dissolving and removing the photoresist layer 106a corresponding to the exposed area using a developer. Specifically, the photoresist pattern 108 is completed by dissolving and removing the photoresist film corresponding to the exposed region using a developer such as tetra-methyl ammonium hydroxide (TMAH).

Subsequently, the resist underlayer layer is etched using the photoresist pattern 108 as an etching mask. The organic layer pattern 112 is formed by the above etching process. The etching may be performed by dry etching using, for example, an etching gas, and the etching gas may be CHF ₃ , CF ₄ , Cl ₂ , O _2, and a mixed gas thereof. As described above, since the resist underlayer film formed by the resist underlayer composition according to an embodiment has a fast etching rate, a smooth etching process can be performed within a short time.

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. In the exposure process performed previously, a thin film pattern 114 formed by an exposure process performed using a short wavelength light source such as an activated irradiation degree i-line (365 nm), a KrF excimer laser (wavelength 248 nm), and an ArF excimer laser (wavelength 193 nm). ) May have a width of several tens to several hundred nm, and the thin film pattern 114 formed by an exposure process performed using an EUV light source may have a width of 20 nm or less.

Hereinafter, the present invention will be described in more detail through examples of the synthesis of the above-described polymer and the preparation of a composition for a resist underlayer film comprising the same. However, the technical limitation of the present invention is not limited by the following examples.

Synthesis example

Synthesis Example 1

A polymer including the structural unit represented by Chemical Formula 2 was synthesized by the method disclosed in Scheme 1 below.

Specifically, first, 1,3-diallyl-5-methyl-1,3,5-triazinan-2,4,6-trione (20 g, 100 mmol) and 1,3-propanediol (10.64 g, 140 mmol) in 500 g of propylene glycol monomethyl ether acetate (PGMEA). Thereafter, iodine (35 g, 140 mmol) was added slowly at 0 °C, and then raised to room temperature (Room Temperaure) to react. Thereafter, when all of the starting materials for the reaction are exhausted, the reaction solution is quenched with 10% Na ₂ S ₂ O ₅ aqueous solution (500 mL). Thereafter, after the solvent was poured out, the remaining solvent was removed using a vacuum pump to obtain a polymer (Mw = 5300 g/mol) containing the structural unit represented by the above-described formula (2).

[Scheme 1]

합성예 2

Synthesis Example 2

A polymer including the structural unit represented by Chemical Formula 3 was synthesized by the method disclosed in Scheme 2 below.

Specifically, a polymer containing the structural unit represented by Formula 3 described above through the same procedure as in Synthesis Example 1, except that 1,3-propanediamine was used instead of 1,3-propanediol (Mw = 7500 g /mol).

[Scheme 2]

Synthesis Example 3

A polymer including the structural unit represented by Chemical Formula 4 was synthesized by the method disclosed in Scheme 3 below.

Specifically, a polymer containing the structural unit represented by Chemical Formula 4 (Mw = 8000 g/mol) through the same process as in Synthesis Example 1, except that adipamide was used instead of 1,3-propanediol Got it.

[Scheme 3]

Synthesis Example 4

A polymer including the structural unit represented by Chemical Formula 5 was synthesized by the method disclosed in Scheme 4 below.

Specifically, instead of 1,3-diallyl-5-methyl-1,3,5-triazine-2,4,6-trione, 2,4-bis(allyloxy)-6-methoxy-1,3 Polymer containing the structural unit represented by the above-described Chemical Formula 5 through the same procedure as in Synthesis Example 1, except that 1,3-propanediamine was used instead of 1,3-propanediol for 5-triazine ( Mw = 7500 g/mol) was obtained.

[Scheme 4]

Synthesis Example 5

A polymer including the structural unit represented by Chemical Formula 6 was synthesized by the method disclosed in Scheme 5 below.

Specifically, instead of 1,3-diallyl-5-methyl-1,3,5-triazine-2,4,6-trione, 2,4-bis(allyloxy)-6-methoxy-1,3 A polymer (Mw = 6900 g/mol) including the structural unit represented by Chemical Formula 6 was obtained through the same procedure as in Synthesis Example 1, except that ,5-triazine was used.

[Scheme 5]

Synthesis Example 6

A polymer including the structural unit represented by Chemical Formula 7 was synthesized by the method disclosed in Scheme 6 below.

Specifically, instead of 1,3-diallyl-5-methyl-1,3,5-triazine-2,4,6-trione, 2,4-bis(allyloxy)-6-methoxy-1,3 An intermediate was prepared through the same procedure as in Synthesis Example 1, except that ,5-triazine was used. Thereafter, the intermediate is dissolved in dimethylformamide (DMF), and then an excess of K ₂ CO ₃ and 1,3-dioxolan-2-one are added and further reacted at 80° C. to obtain the structural unit represented by Formula 7 above. The containing polymer (Mw = 6500 g/mol) was obtained.

[Scheme 6]

Synthesis Example 7

A polymer including the structural unit represented by Chemical Formula 8 was synthesized by the method disclosed in Scheme 7 below.

Specifically, a polymer containing the structural unit represented by Formula 8 described above through the same procedure as in Synthesis Example 1, except that N-bromosuccinimide was used instead of iodine (Mw = 7500 g/mol) Got it.

[Scheme 7]

Comparative Synthesis Example

A polymer including a structural unit represented by the following Formula 9 was synthesized by the method disclosed in Scheme 8 below.

[Formula 9]

25.5 g of monomethyl diglycidyl isocyanuric acid, 16.6 g of terephthalic acid, and _{0.54 g of benzyltriethylammonium chloride (BnEt 3} NCl) were dissolved in 100 g of propylene glycol monomethyl ether (PGMEA), and then at 130° C. for 24 hours By reaction, a polymer (Mw = 7600 g/mol) containing the structural unit represented by Chemical Formula 9 was obtained.

[Scheme 8]

Preparation of a composition for a resist underlayer film

Examples 1 to 8 and Comparative Examples

For each of the polymers prepared from Synthesis Examples 1 to 8 and Comparative Synthesis Examples, 0.5 g of the polymer was prepared in propylene with 0.125 g of PD1174 (TCI; hardener), and 0.125 g of pyridinium para-toluenesulfonate (PPTS). Compositions for resist underlayer films according to Examples 1 to 8 and Comparative Examples were each prepared by completely dissolving in 100 g of a mixed solvent of glycol monomethyl ether and ethyl lactate (mixed volume ratio = 7:3).

Membrane density evaluation

The resist underlayer composition according to Examples 1 to 8 and Comparative Examples was applied on a silicon substrate by a spin-on coating method, respectively, and then heat-treated on a hot plate at 205° C. for 1 minute to form a resist underlayer film having a thickness of about 100 nm. .

Subsequently, the density of the resist underlayer film was measured, and the results are shown in Table 1. The density of the resist underlayer film was measured using an X-Ray Diffractometer (Model: X'Pert PRO MPD, manufactured by Panalytical (Netherlands)).

Example 1 1.44 Example 2 1.48 Example 3 1.51 Example 4 1.52 Example 5 1.47 Example 6 1.54 Example 7 1.41 Example 8 1.40 Comparative example 1.28

Referring to Table 1, it can be seen that the film formed using the composition for the resist underlayer film according to Examples 1 to 8 has a higher density than the film formed using the composition for the resist underlayer film according to the Comparative Example. This is presumed to be because the film density was improved by the aromatic group and the halogen group having a high electron density included in the composition for a resist underlayer film according to Examples 1 to 8.

From the results of Table 1, it can be seen that when the composition for a resist underlayer film according to Examples 1 to 8 is used, a film having a more dense structure can be formed compared to the comparative example.

Evaluation of exposure characteristics

The compositions prepared from Examples 1 to 8 and Comparative Examples were each coated by a spin-on coating method, and then heat-treated on a hot plate at 205° C. for 1 minute to form a resist underlayer film having a thickness of about 10 nm.

Thereafter, a photoresist solution was applied on the photoresist underlayer film by a spin-on coating method, and then heat-treated at 110° C. for 1 minute on a hot plate to form a photoresist layer. The photoresist layer was exposed to an acceleration voltage of 100 keV using an e-beam exposure machine (manufactured by Elionix), and then heat-treated at 110° C. for 60 seconds. Subsequently, the photoresist layer was developed with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) at 23° C. and rinsed in pure water for 15 seconds to form a line and space (L/S) photoresist pattern. Formed.

Next, the optimal exposure amount, resolution, and development residue of the photoresist pattern were evaluated, and the results are shown in Table 2.

Here, an exposure amount that resolves a line and space of 100 nm at 1:1 is referred to as an optimum exposure amount (Eop, μC/cm 2 ), and a minimum line width of a line and space in the optimal exposure amount is referred to as a resolution. The resolution was measured using a scanning electron microscope (SEM) S-9260 (manufactured by Hitachi) at the limiting resolution (nm).

The developing residue is based on the dissolution rate (DR) in a 2.38 mass% aqueous solution of tetramethyl ammonium hydroxide (TMAH), and the higher the speed, the more developed residue after pattern formation (e.g., line width roughness). ) Decreased and the degree of decrease was observed with an electron scanning microscope (SEM) and expressed as ○ for good, △ for poor, and X for poor (bridge formation).

Eop (μC/㎠) Resolution (nm) Development residue status Example 1 125 35 ○ Example 2 150 50 ○ Example 3 140 45 ○ Example 4 135 45 ○ Example 5 120 40 ○ Example 6 130 40 ○ Example 7 110 35 ○ Example 8 120 45 ○ Comparative example 170 65 △

Referring to Table 2, when a resist underlayer film was formed using the composition for a photoresist underlayer film according to Examples 1 to 8, it can be seen that the optimum exposure amount, resolution, and development residue state of the photoresist pattern are all superior compared to the comparative example. Therefore, from the results of Table 2, it can be seen that when the composition for a resist underlayer film according to Examples 1 to 8 is used, a photoresist pattern having more excellent sensitivity compared to the comparative example can be formed.

In the above, although specific embodiments of the present invention have been described and illustrated, the present invention is not limited to the described embodiments, and 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 viewpoint of the present invention, and the modified embodiments should be said to belong to the claims of the present invention.

100: substrate 102: thin film
104: resist underlayer film 106: photoresist film
108: photoresist pattern 110: mask
112: organic layer pattern 114: thin film pattern

Claims (13)

A polymer containing a structural unit represented by the following formula (1); And
menstruum
A composition for a resist underlayer film comprising:
[Formula 1]

In Formula 1,
A is a divalent nitrogen-containing heteroaromatic ring group,
L ₁ , L ₂ , L ₃ are each independently a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C1 to C10 heteroalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or An unsubstituted C2 to C20 heterocycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C1 to C10 heteroarylene group,
X ₁ , X ₂ are each independently selected from halogen groups (-F, -Cl, -Br, -I),
Z ₁ , Z ₂ are each independently oxygen, sulfur, or -N(R ^a-- )- (however, R ^a is hydrogen, deuterium, a halogen group (-F, -Cl, -Br, -I), A substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, or a substituted or unsubstituted C6 to C20 aryl group),
* Is the point of connection. In claim 1,
The divalent nitrogen-containing heteroaromatic ring group is a composition for a resist underlayer film represented by at least one of the following Formulas A-1 and A-2:
[Formula A-1]

[Formula A-2]

In Formula A-1 and Formula A-2,
R ₁ , R ₂ are each independently hydrogen, deuterium, a halogen group (-F, -Cl, -Br, -I), a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group , A substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted A C2 to C20 heteroalkenyl group, a substituted or unsubstituted C3 to C20 heterocycloalkyl group, or a substituted or unsubstituted C6 to C20 heteroaryl group,
* Is the point of connection. In claim 1,
The Z ₁ and Z ₂ are the same composition for a resist underlayer film. In claim 1,
The X ₁ and X ₂ are the same composition for a resist underlayer film. In claim 1,
The structural unit represented by Formula 1 is a composition for a resist underlayer film comprising a structural unit represented by the following Formula 1-1 or the following Formula 1-2:
[Formula 1-1]

[Formula 1-2]

In Formula 1-1 and Formula 1-2,
L ₁₁ , L ₁₂ , L ₁₃ , L ₂₁ , L ₂₂ , L ₂₃ are each independently a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C1 to C10 heteroalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C2 to C20 heterocycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C1 to C10 heteroarylene group,
R ₁₁ and R ₂₁ are each independently hydrogen, deuterium, a halogen group (-F, -Cl, -Br, -I), a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group , A substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted A C2 to C20 heteroalkenyl group, a substituted or unsubstituted C3 to C20 heterocycloalkyl group, or a substituted or unsubstituted C6 to C20 heteroaryl group,
X is selected from halogen groups (-F, -Cl, -Br, -I),
Z is oxygen, sulfur, or -N(R ^a-- )-, or -N(R ^a-- )- (However, R ^a is hydrogen, deuterium, halogen group (-F, -Cl, -Br,- I), a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, or a substituted or unsubstituted C6 to C20 aryl group),
n and m are each independently an integer of 2 to 100. In claim 1,
The polymer is a composition for a resist underlayer film comprising at least one of the structural units represented by the following Chemical Formulas 2 to 8:
[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

In claim 1,
A composition for a resist underlayer film having a weight average molecular weight of 1,000 to 100,000 g/mol of the polymer. In claim 1,
The polymer is a composition for a resist underlayer film containing 0.1% to 50% by weight based on a total of 100% by weight of the resist underlayer film composition. In claim 1,
A composition for a resist underlayer film further comprising one or more polymers selected from acrylic resins, epoxy resins, novolac resins, glycoluril resins, and melamine resins. In claim 1,
A composition for a resist underlayer film further comprising an additive including a surfactant, a thermal acid generator, a plasticizer, or a combination thereof. Forming a layer to be etched on the substrate,
Forming a resist underlayer film by applying the composition for a resist underlayer film according to any one of claims 1 to 10 on the etching target film,
Forming a photoresist pattern on the resist underlayer film, and
Sequentially etching the resist underlayer layer and the etching target layer using the photoresist pattern as an etching mask
Pattern forming method comprising a. In clause 11,
The step of forming the photoresist pattern
Forming a photoresist film on the resist underlayer film,
Exposing the photoresist film, and
A method of forming a pattern comprising developing the photoresist film. In clause 11,
The step of forming the resist underlayer film further comprises performing heat treatment at a temperature of 100°C to 500°C after coating the composition for the resist underlayer film.

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