KR102215332B1 - Resist underlayer composition, and method of forming patterns using the composition - Google Patents

Abstract

상기 화학식 1의 정의는 명세서 내에 기재한 바와 같다.It provides 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]

The definition of Formula 1 is as described in the specification.

Description

Resist underlayer composition and pattern formation 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.

In the lithographic technique, a photoresist film is coated on a semiconductor substrate such as a silicon wafer, exposed and developed to form a thin film, and activated radiation such as ultraviolet rays is irradiated through a mask pattern on which the device pattern is drawn, and developed. , A processing method of forming a fine pattern corresponding to the pattern on the surface of the substrate by etching the substrate using the obtained photoresist pattern as a protective film.

As ultra-fine pattern manufacturing technology is required, short wavelengths such as i-line (365 nm), KrF excimer laser (wavelength 248 nm), and ArF excimer laser (wavelength 193 nm) are also used for the exposure of photoresist. Accordingly, in order to solve the problems caused by the diffuse reflection or standing wave from the semiconductor substrate of the activated radiation, many studies have been made to solve the problem by interposing a resist underlayer having an optimized reflectance between the resist and the semiconductor substrate. have

On the other hand, as a light source for fine pattern manufacturing in addition to the activated radiation, a method of using high energy rays such as EUV (Extreme ultraviolet; wavelength 13.5 nm) and E-Beam (electron beam) is also performed. Although there is no reflection, studies on improving the adhesion between the resist and the lower film are also being widely studied in order to improve the collapse of the pattern formed as the pattern is refined. In addition, studies to improve etch selectivity and chemical resistance in addition to studies to reduce the problems caused by the light source as described above are also widely studied.

In addition, attempts to improve the etch selectivity, chemical resistance, and adhesion to the resist, along with studies to reduce the problems caused by the light source as described above, have been continued.

One embodiment provides a composition for a resist underlayer film having excellent coating properties and a fast etch rate.

Another embodiment provides a method of forming a pattern 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,

L ¹ and L ² are each independently a single bond, -O-, -S-, -S(=O)-, -S(=O) ₂ -, -C(=O)-, -(CO) O-, -O(CO)O-, a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C2 to C10 alkenylene group, a substituted or unsubstituted C2 to C10 alkynylene group, a substituted or Unsubstituted C3 to C10 cycloalkylene group, substituted or unsubstituted C2 to C10 heterocycloalkylene group, substituted or unsubstituted C6 to C30 arylene group, substituted or unsubstituted C2 to C30 heteroarylene group, or these Is a combination of,

A is a substituted or unsubstituted C1 to C30 alkylene group, a substituted or unsubstituted C2 to C30 alkenylene group, a substituted or unsubstituted C3 to C30 cycloalkylene group, a substituted or unsubstituted C6 to C30 arylene group, or It is represented by Formula 2 or Formula 3:

[Formula 2]

In Chemical Formula 2,

X ¹ and X ³ are each independently CR ^a R ^b or -C(=O)-,

X ² is CR ^a R ^b or NR ^c ,

The R ^a , R ^b and R ^c are each independently hydrogen, deuterium, halogen group, hydroxy group, cyano group, nitro group, amino group, epoxy group, vinyl group, (meth)acrylate group, oxetane group, thiol Group, carboxyl group, substituted or unsubstituted C1 to C30 alkyl group, substituted or unsubstituted C2 to C30 alkenyl group, substituted or unsubstituted C2 to C30 alkynyl group, substituted or unsubstituted C1 to C10 alkoxy group , A substituted or unsubstituted C3 to C10 cycloalkyl group, a substituted or unsubstituted C1 to C30 thioalkyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C6 to C30 aryloxy group, A substituted or unsubstituted C6 to C30 thioaryl group, or a combination thereof;

[Formula 3]

In Chemical Formula 3,

L ³ is each independently a single bond, -O-, -S-, -S(=O)-, -S(=O) ₂ -, -C(=O)-, -NH(CO)-, -NH(CO)O-, -(CO)O-, -O(CO)O-, substituted or unsubstituted C1 to C20 alkylene group, substituted or unsubstituted C2 to C10 alkenylene group, substituted or unsubstituted A substituted or unsubstituted C2 to C10 alkynylene group, a substituted or unsubstituted C3 to C10 cycloalkylene group, a substituted or unsubstituted C2 to C10 heterocycloalkylene group, a substituted or unsubstituted C6 to C30 arylene group, or these Is a combination of,

X ⁴ is hydrogen, deuterium, halogen group, hydroxy group, cyano group, nitro group, amino group, epoxy group, vinyl group, (meth)acrylate group, oxetane group, thiol group, carboxyl group, substituted or unsubstituted C1 to C30 alkyl group, substituted or unsubstituted C2 to C30 alkenyl group, substituted or unsubstituted C2 to C30 alkynyl group, substituted or unsubstituted C1 to C10 alkoxy group, substituted or unsubstituted C1 to C30 thioalkyl group , A substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C6 to C30 aryloxy group, a substituted or unsubstituted C6 to C30 thioaryl group, A substituted or unsubstituted C2 to C30 heteroaryl group, or a combination thereof,

In Formulas 1 to 3, n1 to n9 are each independently an integer of 0 to 10,

* Is the 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 it provides a pattern forming method comprising the step of sequentially etching the resist lower layer layer and the etching target layer using the photoresist pattern using an etching mask.

The composition for a resist underlayer film according to an embodiment may provide a resist underlayer film capable of reducing a possibility of occurrence of defects as it has excellent coating properties and a fast etch rate.

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 embodiment.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can 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 thicknesses are enlarged 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 in the specification, the term'substituted' means that the hydrogen atom in the compound is a halogen atom (F, Br, Cl, or I), a hydroxy group, an alkoxy group, a nitro group, a cyano group, an amino group, an azido group, or an amino group. Dino group, hydrazino group, hydrazono group, carbonyl group, carbamyl group, thiol group, ester group, carboxyl group or salt thereof, sulfonic acid group or salt thereof, phosphoric acid or salt thereof, vinyl group, C1 to C20 alkyl group, C2 to C20 alke Nyl 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.

In addition, unless otherwise defined in the specification,'*' refers to a connection point of a compound or a compound moiety.

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 and a solvent including a structural unit represented by Formula 1 below.

[Formula 1]

In Formula 1,

L ¹ and L ² are each independently a single bond, -O-, -S-, -S(=O)-, -S(=O) ₂ -, -C(=O)-, -(CO) O-, -O(CO)O-, a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C2 to C10 alkenylene group, a substituted or unsubstituted C2 to C10 alkynylene group, a substituted or Unsubstituted C3 to C10 cycloalkylene group, substituted or unsubstituted C2 to C10 heterocycloalkylene group, substituted or unsubstituted C6 to C30 arylene group, substituted or unsubstituted C2 to C30 heteroarylene group, or these Is a combination of,

A is a substituted or unsubstituted C1 to C30 alkylene group, a substituted or unsubstituted C2 to C30 alkenylene group, a substituted or unsubstituted C3 to C30 cycloalkylene group, a substituted or unsubstituted C6 to C30 arylene group, or It is represented by Formula 2 or Formula 3 below:

[Formula 2]

In Chemical Formula 2,

X ¹ and X ³ are each independently CR ^a R ^b or -C(=O)-,

X ² is CR ^a R ^b Or NR ^c ,

The R ^a , R ^b and R ^c are each independently hydrogen, deuterium, halogen group, hydroxy group, cyano group, nitro group, amino group, epoxy group, vinyl group, (meth)acrylate group, oxetane group, thiol Group, carboxyl group, substituted or unsubstituted C1 to C30 alkyl group, substituted or unsubstituted C2 to C30 alkenyl group, substituted or unsubstituted C2 to C30 alkynyl group, substituted or unsubstituted C1 to C10 alkoxy group , A substituted or unsubstituted C3 to C10 cycloalkyl group, a substituted or unsubstituted C1 to C30 thioalkyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C2 to C30 heteroaryl group, a substituted or An unsubstituted C6 to C30 aryloxy group, a substituted or unsubstituted C6 to C30 thioaryl group, or a combination thereof;

[Formula 3]

In Chemical Formula 3,

L ³ is each independently a single bond, -O-, -S-, -S(=O)-, -S(=O) ₂ -, -C(=O)-, -NH(CO)-, -NH(CO)O-, -(CO)O-, -O(CO)O-, substituted or unsubstituted C1 to C20 alkylene group, substituted or unsubstituted C2 to C10 alkenylene group, substituted or unsubstituted A substituted or unsubstituted C2 to C10 alkynylene group, a substituted or unsubstituted C3 to C10 cycloalkylene group, a substituted or unsubstituted C2 to C10 heterocycloalkylene group, a substituted or unsubstituted C6 to C30 arylene group, a substituted or Unsubstituted C2 to C30 heteroarylene group, or a combination thereof,

X ⁴ is hydrogen, deuterium, halogen group, hydroxy group, cyano group, nitro group, amino group, epoxy group, vinyl group, (meth)acrylate group, oxetane group, thiol group, carboxyl group, substituted or unsubstituted C1 to C30 alkyl group, substituted or unsubstituted C2 to C30 alkenyl group, substituted or unsubstituted C2 to C30 alkynyl group, substituted or unsubstituted C1 to C10 alkoxy group, substituted or unsubstituted C1 to C30 thioalkyl group , A substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C2 to C30 heteroaryl group, a substituted or unsubstituted C2 to C30 heteroaryl group, a substituted or An unsubstituted C6 to C30 aryloxy group, a substituted or unsubstituted C6 to C30 thioaryl group, or a combination thereof,

In Formulas 1 to 3, n1 to n9 are each independently an integer of 0 to 10,

* Is the connection point.

The polymer in the composition according to an embodiment includes a structural unit including a carbonate group. In the case of a composition containing a structural unit containing a carbonate group, the polymer can be etched at a faster rate than a photoresist film in a dry etching process for a photoresist film, compared to a case where the polymer contains a structural unit not containing a carbonate group. have. In addition, when a semiconductor substrate, for example, a silicon substrate is coated with a thin film, a higher adhesion can be secured and the coating can be coated with a more uniform thickness, so that higher coating uniformity can be secured.

In one embodiment, in Formula 1, A may be represented by any one of a C1 to C30 alkylene group, a C6 to C30 arylene group, and Formula 2 and Formula 3.

For example, in Formula 1, A may be a C1 to C10 alkylene group, L ¹ and L ² may be -O-, n2 and n4 may be 1, and n3 and n4 may be 0.

For example, in Formula 1, A may be represented by Formula 2,

In Formula 2, X ¹ and X ³ are each -C(=O), X ² is NR ^c ,

Here, R ^c is a hydroxy group, a cyano group, a nitro group, an amino group, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C10 alkoxy group, a substituted or unsubstituted C3 to C10 cyclo It may be an alkyl group, a substituted or unsubstituted C1 to C30 thioalkyl group, or a combination thereof.

In another embodiment, A in Formula 1 may be represented by Formula 2, and in Formula 2, X ¹ to X ³ are each CR ^a R ^b Is, where,

R ^a and Each of R ^b is independently hydrogen, deuterium, halogen group, hydroxy group, cyano group, nitro group, amino group, epoxy group, thiol group, carboxyl group, substituted or unsubstituted C1 to C30 alkyl group, substituted or unsubstituted C1 To C10 alkoxy group, substituted or unsubstituted C3 to C10 cycloalkyl group, substituted or unsubstituted C1 to C30 thioalkyl group, or a combination thereof.

In addition, in another embodiment, A in Formula 1 is represented by Formula 3, and in Formula 3, L ³ is -O-, or -S-,

X ⁴ is a hydroxy group or a thiol group,

n7 and n9 are each independently one of an integer from 0 to 5,

n8 can be 0 or 1.

In one embodiment, the polymer may include two or more structural units represented by Chemical Formula 1 but having different structures.

When the polymer includes a first structural unit and a second structural unit different from each other, the first structural unit may be a structural unit in which A in Formula 1 is represented by Formula 2, and the second structural unit is in Formula 1 A of may be a structural unit represented by Chemical Formula 3. Alternatively, when the polymer includes a first structural unit and a second structural unit different from each other, both the first structural unit and the second structural unit are structural units in which A in Formula 1 is represented by Formula 2, or In both the first structural unit and the second structural unit, A in Formula 1 may be a structural unit represented by Formula 3.

Alternatively, when the polymer includes a first structural unit and a second structural unit different from each other, the first structural unit is a substituted or unsubstituted C to C30 alkylene group in Formula 1, and the second structural unit is the A in Formula 1 may be a structural unit represented by Formula 2 or a structural unit represented by Formula 3.

Alternatively, the polymer may include three or more different structural units represented by Formula 1, but in this case, for example, in the first structural unit, A in Formula 1 is a C1 to C30 alkylene group or C6 to It is a C30 arylene group, and as for the second structural unit, A in Formula 1 may be represented by Formula 2, and the third structural unit may include a structural unit in which A in Formula 1 is represented by Formula 3.

In one embodiment, the polymer includes the structural unit represented by Formula 1, but includes a first structural unit and a second structural unit having different structures, wherein the first structural unit and the second structural unit are In all, A in Formula 1 is represented by Formula 2, in the first structural unit,

X ¹ and X ³ are each -C(=O),

Wherein X ² is NR ^c , wherein.

Wherein R ^c is a hydroxy group, a cyano group, a nitro group, an amino group, a C1 to C30 alkyl group, a C1 to C10 alkoxy group, or a combination thereof,

In the second structural unit, X ¹ and X ³ in Formula 2 are each -C(=O),

X ² is NR ^c ,

The R ^c may be a C1 to C30 alkyl group, a C2 to C30 alkenyl group, a C2 to C30 alkynyl group, a C3 to C10 cycloalkyl group, or a combination thereof.

In one embodiment, the polymer represented by Formula 1 may include one or more of structural units represented by Formulas 4 to 9 below.

[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

[Formula 9]

Since the polymer according to an embodiment contains a carbonate group in the structural unit represented by Chemical Formula 1, it can have a higher etch rate, adhesion, and coating uniformity than a polymer containing a structural unit not including a carbonate group. have.

Meanwhile, the polymer may have a weight average molecular weight 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 20,000. By having a weight average molecular weight in the above range, the carbon content of the composition for a resist underlayer film containing the polymer and the solubility in a solvent can be adjusted to optimize.

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, since the polymer is stable against organic solvents and heat, when a composition for a resist underlayer film containing the polymer is used as a material for a photoresist underlayer film, for example, it is peeled off by a solvent or heat during a process for forming a photoresist pattern. Or, it is possible to minimize the generation of by-products due to the generation of chemical substances, etc., and the thickness loss due to the upper photoresist solvent can be minimized.

In addition, the polymer has excellent solubility to form a resist underlayer film having excellent coating uniformity. When the polymer is used as a material for a resist underlayer film, formation of pin-holes and voids or thickness distribution during the baking process It is possible to form a uniform thin film without deterioration of, and provide excellent gap-fill and planarization characteristics when there is a step difference in the lower substrate (or film) or when a pattern is formed.

The composition for a resist underlayer film according to an embodiment has excellent coating uniformity, excellent stability, and a high refractive index, and since the etching speed is also fast, the activation radiation is i-line (365 nm), KrF excimer laser (wavelength 248 nm). ), ArF excimer laser (wavelength 193 nm), as well as a lithography process using a light source in a short wavelength range, as well as an ultra-fine pattern process such as an EUV (Extreme Ultraviolet) lithography process. The EUV lithography process is a lithography technology 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.

The solvent is not particularly limited as long as it has sufficient solubility or dispersibility in the polymer, for example, 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 composition for the resist underlayer film may further include a crosslinking agent.

The crosslinking agent may be, for example, melamine-based, substituted urea-based, or these polymers. Preferably, a crosslinking agent having at least two crosslinking substituents, for example, methoxymethylated glycoruryl, butoxymethylated glycoruryl, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxy Compounds such as methylated benzoguanamine, methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, or butoxymethylated thiourea may be used.

As the crosslinking agent, a crosslinking agent having high heat resistance may be used, and for example, a compound containing a crosslinking substituent having an aromatic ring (eg, a benzene ring or a naphthalene ring) in the molecule may be used. The crosslinking agent may, for example, have two or more crosslinking sites.

In addition, the composition for the resist underlayer film may further include at least one other polymer among acrylic resins, epoxy resins, novolac resins, glucouryl resins and melamine resins in addition to the polymer containing the structural unit represented by Formula 1 However, it 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, etc. ,4,6-tetrabromocyclohexadienone, benzointosylate, 2-nitrobenzyltosylate, and other organic fonate alkyl esters may be used, but the present invention is not limited thereto.

The additive may be included in an amount of about 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 by using the above-described composition for a resist underlayer film is provided. The resist underlayer film may have a form cured through a heat treatment process after coating the above-described resist underlayer film composition on a substrate, for example. The resist underlayer film may be, for example, an antireflection film.

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, etc. 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.

Thereafter, drying and baking processes are performed to form a resist underlayer layer 104 on the thin film. The baking treatment may be performed at about 100 to about 500, for example, at about 100 to about 300. 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 redundancy.

Referring to FIG. 2, a photoresist film 106 is formed by coating a photoresist on the resist underlayer 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 photoresist containing alkali-soluble resin, chemically amplified type containing alkali-soluble resin with groups 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.

Subsequently, a first baking process of heating the substrate 100 on which the photoresist layer 106 is formed is performed. The first baking process may be performed at a temperature of about 90 to about 120.

3, the photoresist layer 106 is selectively exposed.

When an exposure process for exposing the photoresist film 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 106b of the exposed region has a relatively hydrophilicity compared to the photoresist film 106a of the unexposed region. Accordingly, the photoresist film of the exposed portion 106b and the non-exposed portion 106a 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 about 90 to about 150. By performing the second baking process, the photoresist film corresponding to the exposed area becomes soluble in a specific solvent.

Referring to FIG. 4, a photoresist pattern 108 is formed by dissolving and removing the photoresist film 106b 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).

Then, 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 , BCl _3, 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 of nm to several hundreds of 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 limitations of the present invention are not limited by the following examples.

Synthesis example

Synthesis example One

1,3,5-Tris(2-hydroxyethyl)isocyanurate (15.67g, 0.06mol), Dimethyl carbonate (3.60g, 0.04mol), Potassium hydroxide (0.44g, 8mmol), and tetrahydrofuran in a 250mL 2-neck round flask. (THF) 79g was put and stirred at 60°C using a magnetic bar. After reacting for 6 hours, the temperature was lowered to room temperature, and the reactant was added to an excessive amount of hexane, stirred and allowed to stand, and the supernatant was removed. Then, the reactant solution is added to toluene, stirred and allowed to stand, and the supernatant is removed. In this way, a polymer (Mw = 4,000) including a structural unit represented by the following formula (4) was finally obtained by purifying after removing the low molecule and the catalyst.

[Formula 4]

Synthesis example 2

Triethylene glycol (9.01g, 0.06mol), Dimethyl carbonate (3.60g, 0.04mol), potassium hydroxide (0.44g, 8mmol), and tetrahydrofuran (THF) 52.2g were added to a 250mL two-necked round flask, using a magnetic bar. It was stirred at 60°C. After reacting for 6 hours, the temperature was lowered to room temperature, and the reactant was added to an excessive amount of hexane, stirred and allowed to stand, and the supernatant was removed. Then, the reactant solution is added to toluene, stirred and allowed to stand, and the supernatant is removed. In this way, a polymer (Mw = 6,500) containing a structural unit represented by the following Chemical Formula 5 was finally obtained by purifying after removing the low molecule and the catalyst.

[Formula 5]

Synthesis example 3

In a 250 mL two neck round flask, 2-[4,6-Bis-(2-hydroxy-ethoxy)-[1,3,5]triazin-2-yloxy]-ethanol (15.67 g, 0.06 mol), Dimethyl carbonate (3.60) g, 0.04mol), potassium hydroxide (0.44g, 8mmol), and 79 g of tetrahydrofuran (THF) were added and stirred at 60°C using a magnetic bar. After reacting for 6 hours, the temperature was lowered to room temperature, and the reactant was added to an excessive amount of hexane, stirred and allowed to stand, and the supernatant was removed. Then, the reactant solution is added to toluene, stirred and allowed to stand, and the supernatant is removed. In this way, a polymer (Mw = 5,500) containing a structural unit represented by the following Chemical Formula 6 was finally obtained by purifying after removing the low molecule and the catalyst.

[Formula 6]

Synthesis example 4

1,3,5-Tris(2-hydroxyethyl)isocyanurate (7.84g, 0.03mol), 1,3-di(2-hydroxyethyl),5-pentyl isocyanurate (8.61g,0.03mol), in a 250mL 2-neck round flask Dimethyl carbonate (3.60g, 0.04mol), potassium hydroxide (0.44g, 8mmol), and 82g of tetrahydrofuran (THF) were added and stirred at 60°C using a magnetic bar. After reacting for 6 hours, the temperature was lowered to room temperature, and the reactant was added to an excessive amount of hexane, stirred and allowed to stand, and the supernatant was removed. Then, the reactant solution is added to toluene, stirred and allowed to stand, and the supernatant is removed. In this way, a polymer (Mw = 3,500) containing a structural unit represented by the following Formula 7 was obtained by purifying after removing the low molecule and the catalyst.

[Formula 7]

Synthesis example 5

In a 250mL 2-neck round flask, 1,3-Bis-(2-hydroxy-ethyl)-tetrahydro-pyrimidin-2-one (11.29g, 0.06mol), Dimethyl carbonate (3.60g, 0.04mol), Potassium hydroxide (0.44g) , 8mmol), and tetrahydrofuran (THF) 60.33g were added and stirred at 60°C using a magnetic bar. After reacting for 6 hours, the temperature was lowered to room temperature, and the reactant was added to an excessive amount of hexane, stirred and allowed to stand, and the supernatant was removed. Then, the reactant solution is added to toluene, stirred and allowed to stand, and the supernatant is removed. In this way, a polymer (Mw = 4,000) containing a structural unit represented by the following formula (8) was finally obtained by purifying after removing the low molecule and the catalyst.

[Formula 8]

Synthesis example 6

Cyanuric acid (7.74g, 0.06mol), Dimethyl carbonate (3.60g, 0.04mol), Potassium hydroxide (0.44g, 8mmol), and tetrahydrofuran (THF) 47.14g were added to a 250mL 2-neck round flask, and then using a magnetic bar. It was stirred at 60°C. After reacting for 6 hours, the temperature was lowered to room temperature, and the reactant was added to an excessive amount of hexane, stirred and allowed to stand, and the supernatant was removed. Then, the reactant solution is added to toluene, stirred and allowed to stand, and the supernatant is removed. In this way, a polymer (Mw = 5,000) containing a structural unit represented by the following formula (9) was finally obtained by purifying after removing the low molecule and the catalyst.

[Formula 9]

compare Synthesis example

Methyl methacrylate (40g), 2-hydroxyacrylate (52.1g), Benzyl acrylate (70.4g), AIBN (2g), and Dioxane (306g) were added to a 500ml 2-neck round flask, and a condenser was connected. The temperature was raised to 80° C., and after reaction for 2.5 hours, the reaction solution was cooled to room temperature. The reaction solution was transferred to a 3 L light bulb and washed with hexane. The obtained resin was dried in a vacuum oven at 30° C. to remove the residual solvent to finally obtain a polymer (Mw = 12,000) containing the structural unit represented by the following formula (10).

[Formula 10]

Resist For the lower layer Preparation of the composition

Example One

The polymer prepared from Synthesis Example 1, PD1174 (TCI; hardener) (15 parts by weight based on 100 parts by weight of the polymer) and Pyridinium p-toluenesulfonate (1 part by weight based on 100 parts by weight of the polymer) were added to propylene glycol monomethyl ether and ethyllac. After dissolving in a mixed solvent of tate (mixed weight ratio = 1:1), the mixture was stirred for 6 hours to prepare an antireflection film composition.

The content of the mixed solvent was adjusted so that the polymer solid content was 2% by weight based on the total content of the antireflection film composition to be prepared.

Example 2

It was carried out in the same manner as in Example 1, except that the polymer of Synthesis Example 2 was used.

Example 3

It was carried out in the same manner as in Example 1, except that the polymer of Synthesis Example 3 was used.

Example 4

It was carried out in the same manner as in Example 1, except that the polymer of Synthesis Example 4 was used.

Example 5

It was carried out in the same manner as in Example 1, except that the polymer of Synthesis Example 3 was used.

Example 6

It was carried out in the same manner as in Example 1, except that the polymer of Synthesis Example 4 was used.

Comparative example One

It was carried out in the same manner as in Example 1, except that the polymer of Comparative Synthesis Example 1 was used.

Evaluation: Coating uniformity and Etch Selectivity

2 ml each of the compositions prepared from Examples 1 to 6 and Comparative Example 1 were each applied onto an 8-inch wafer and then spin-coated for 20 seconds at a main spin speed of 1,500 rpm using an auto track (TEL ACT-8). After proceeding, curing at 210° C. for 90 seconds to form a 300 nm-thick thin film. The uniformity was compared by measuring the thickness of 51 points along the horizontal axis.

Coating uniformity(%) Example 1 1.8 Example 2 1.9 Example 3 1.8 Example 4 2.1 Example 5 2.0 Example 6 1.8 Comparative Example 1 2.1

In addition, the results of measuring the etch selectivity of each thin film under the etch conditions of 10mT / 600_35W / 120CF4 / 80CHF3 / 41O2 and 22sec are shown in Table 2 below.

Å/sec Example 1 27.5 Example 2 29.7 Example 3 28.8 Example 4 29.4 Example 5 30.1 Example 6 27.8 Comparative Example 1 33.5

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. Therefore, such modifications or variations should not be individually understood from the technical spirit or point of view 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 (16)

A composition for a resist underlayer film comprising a polymer comprising a structural unit represented by the following formula (1) and a solvent:
[Formula 1]

In Formula 1,
L ¹ and L ² are each independently a single bond, -O-, -S-, -S(=O)-, -S(=O) ₂ -, -C(=O)-, -(CO) O-, -O(CO)O-, a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C2 to C10 alkenylene group, a substituted or unsubstituted C2 to C10 alkynylene group, a substituted or Unsubstituted C3 to C10 cycloalkylene group, substituted or unsubstituted C2 to C10 heterocycloalkylene group, substituted or unsubstituted C6 to C30 arylene group, substituted or unsubstituted C2 to C30 heteroarylene group, or these Is a combination of,
A is a substituted or unsubstituted C1 to C30 alkylene group, a substituted or unsubstituted C2 to C30 alkenylene group, a substituted or unsubstituted C3 to C30 cycloalkylene group, a substituted or unsubstituted C6 to C30 arylene group, or It is represented by Formula 2 or Formula 3 below:
[Formula 2]

In Chemical Formula 2,
X ¹ and X ³ are each independently CR ^a R ^b or -C(=O)-,
X ² is CR ^a R ^b Or NR ^c ,
The R ^a , R ^b and R ^c are each independently hydrogen, deuterium, halogen group, hydroxy group, cyano group, nitro group, amino group, epoxy group, vinyl group, (meth)acrylate group, oxetane group, thiol Group, carboxyl group, substituted or unsubstituted C1 to C30 alkyl group, substituted or unsubstituted C2 to C30 alkenyl group, substituted or unsubstituted C2 to C30 alkynyl group, substituted or unsubstituted C1 to C10 alkoxy group , A substituted or unsubstituted C3 to C10 cycloalkyl group, a substituted or unsubstituted C1 to C30 thioalkyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C2 to C30 heteroaryl group, a substituted or An unsubstituted C6 to C30 aryloxy group, a substituted or unsubstituted C6 to C30 thioaryl group, or a combination thereof;
[Formula 3]

In Chemical Formula 3,
L ³ is each independently a single bond, -O-, -S-, -S(=O)-, -S(=O) ₂ -, -C(=O)-, -NH(CO)-, -NH(CO)O-, -(CO)O-, -O(CO)O-, substituted or unsubstituted C1 to C20 alkylene group, substituted or unsubstituted C2 to C10 alkenylene group, substituted or unsubstituted A substituted or unsubstituted C2 to C10 alkynylene group, a substituted or unsubstituted C3 to C10 cycloalkylene group, a substituted or unsubstituted C2 to C10 heterocycloalkylene group, a substituted or unsubstituted C6 to C30 arylene group, a substituted or It is an unsubstituted C2 to C30 heteroarylene group, or a combination thereof,
X ⁴ is hydrogen, deuterium, halogen group, hydroxy group, cyano group, nitro group, amino group, epoxy group, vinyl group, (meth)acrylate group, oxetane group, thiol group, carboxyl group, substituted or unsubstituted C1 to C30 alkyl group, substituted or unsubstituted C2 to C30 alkenyl group, substituted or unsubstituted C2 to C30 alkynyl group, substituted or unsubstituted C1 to C10 alkoxy group, substituted or unsubstituted C1 to C30 thioalkyl group , Substituted or unsubstituted C3 to C30 cycloalkyl group, substituted or unsubstituted C6 to C30 aryl group, substituted or unsubstituted C2 to C30 heteroaryl group, substituted or unsubstituted C6 to C30 aryloxy group, substituted Or an unsubstituted C6 to C30 thioaryl group, or a combination thereof,
In Formulas 1 to 3, n1 to n9 are each independently an integer of 0 to 10,
* Is the connection point. In claim 1,
In Formula 1,
The A is a C1 to C30 alkylene group, a C6 to C30 arylene group, a composition represented by any one of Formula 2 and Formula 3. In claim 1,
The polymer is represented by Chemical Formula 1, but a composition comprising two or more structural units having different structures. In paragraph 3,
The composition, wherein the polymer comprises a first structural unit and a second structural unit different from each other. In claim 4,
The first structural unit is a structural unit in which A in Formula 1 is represented by Formula 2,
The second structural unit is the structural unit A in the formula (1) is represented by the formula (3). In claim 4,
In both the first structural unit and the second structural unit, A in Formula 1 is a structural unit represented by Formula 2, or both of the first structural unit and the second structural unit are A in Formula 1 A composition that is a structural unit represented by Chemical Formula 3. In claim 4,
The polymer further comprises a third structural unit different from each of the first structural unit and the second structural unit. In clause 7,
In the first structural unit, A in Formula 1 is a C1 to C30 alkylene group or a C6 to C30 arylene group,
The second structural unit is a structural unit in which A in Formula 1 is represented by Formula 2,
The third structural unit is the structural unit A in the formula (1) is represented by the formula (3), the composition. 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 4 to 9:
[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

[Formula 9]

. In claim 1,
A composition for a resist underlayer film having a weight average molecular weight of 1,000 to 100,000 of the polymer. In claim 1,
The polymer is 0.1 to 50% by weight, based on the total content of the composition, the resist underlayer composition containing. The method of claim 1,
The composition further comprises a crosslinking agent having two or more crosslinking sites for a resist underlayer film. The method of claim 1,
The composition is a composition for a resist underlayer film further comprising a surfactant, a thermal acid generator, a plasticizer, or an additive of 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 13 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 14,
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 14,
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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