KR102563289B1 - Resist underlayer composition, and method of forming patterns using the composition - Google Patents

Abstract

A polymer comprising a structural unit represented by Formula 1, a structural unit represented by Formula 2, or a combination thereof; and a composition for a resist underlayer film containing a solvent; And it relates to a pattern formation method using the composition for a resist underlayer film:
[Formula 1]

[Formula 2]

The definitions of Formula 1 and Formula 2 are as described in the specification.

Description

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

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

In recent years, the semiconductor industry has been developing from hundreds of nanometer-sized patterns to ultra-fine technologies having several to several tens of nanometer-sized patterns. Effective lithographic techniques are essential to realize these ultra-fine technologies.

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

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

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

On the other hand, in addition to the activation radiation, a method of using high-energy rays such as EUV (Extreme ultraviolet; wavelength 13.5 nm) and E-Beam (electron beam) as a light source for fine pattern production has also been made, and in the case of the light source, reflection from the substrate has been made. Although there is little, the thickness of the resist underlayer film has to be further thinned according to pattern refinement, and research on improving the adhesion between the resist and the underlayer film has been widely reviewed to improve the collapse of the formed pattern. In addition, in order to maximize the efficiency of the light source, research on improving sensitivity through an underlayer film is being reviewed.

Resist pattern collapse does not occur even in the fine patterning process, it is formed into an ultra-thin film, so the etching process time can be shortened, and the patterning performance and efficiency can be improved by improving the sensitivity and light absorption efficiency for an exposure light source. Provide a composition for a resist underlayer film do.

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

A polymer comprising a structural unit represented by Formula 1, a structural unit represented by Formula 2, or a combination thereof; and a solvent for a resist underlayer film.

[Formula 1]

In Formula 1,

A is a nitrogen-containing heterocyclic group,

R ¹ and R ² are, each independently, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, a vinyl group, an allyl group, a substituted or unsubstituted C2 to C10 alkynyl group, or a substituted Or an unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted C1 to C10 heteroalkenyl group, a substituted or unsubstituted C1 to C10 heteroalkynyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted A C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C1 to C20 heteroaryl group, or a functional group represented by the following formula K,

* is the point connected to the main chain or end of the polymer,

[Formula K]

In the above formula K,

L ¹ is 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, or a substituted or unsubstituted C2 to C20 heterocycloalkylene group , A substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C1 to C20 heteroarylene group, or a combination thereof,

R ^k is a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C3 to C20 heterocycloalkyl group, A cyclic C6 to C20 aryl group, or a substituted or unsubstituted C1 to C20 heteroaryl group,

a is an integer from 0 to 2;

* is a point connected to A in Formula 1;

[Formula 2]

In Formula 2,

A is a nitrogen-containing heterocyclic group,

L ¹ , L ² and 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, or a substituted Or an unsubstituted C2 to C20 heterocycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C1 to C20 heteroarylene group, or a combination thereof,

a is an integer from 0 to 2;

R ^k is as defined in Formula K above,

* is a point connected to the main chain or terminal of the polymer,

At least one of R ¹ and R ² of the structural units represented by Formula 1 included in the polymer is represented by Formula K, wherein a in Formula K is an integer of 1 or 2, or

At least one of the structural units represented by Chemical Formula 2 included in the polymer is an integer of 1 or 2.

The A may be represented by at least one of Formula A-1 or Formula A-2.

[Formula A-1]

[Formula A-2]

In Formula A-1 and Formula A-2,

* Represents a polymer backbone or a point connected to any one of R ¹ , R ² , and R ^k .

R ¹ and R ² in Formula 1 are each independently a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, a vinyl group, an allyl group, a substituted or unsubstituted C2 to C10 an alkynyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a functional group represented by Formula K above;

L ¹ in Formula K is a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a combination thereof;

R ^k 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.

L ¹ , L ² , and L ³ in Formula 2 are each independently a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or a substituted or unsubstituted C6 to C20 It may be an arylene group, or a combination thereof.

R ¹ and R ² in Formula 1 are each independently an allyl group or a functional group represented by Formula K,

L ¹ of Formula K is a substituted or unsubstituted C1 to C10 alkylene group,

R ^k may be a C1 to C10 alkyl group substituted with a hydroxy group or a thiol group.

L ¹ , L ² , and L ³ in Formula 2 may each independently be a substituted or unsubstituted C1 to C10 alkylene group.

The polymer may include at least one of structural units represented by Chemical Formulas 3 to 5 below.

[Formula 3]

[Formula 4]

[Formula 5]

In Formulas 3 to 5, a is an integer of 1 or 2,

* is the point connected to the main chain or terminal of the polymer.

The polymer may be represented by any one of Formulas 6 to 8 below.

[Formula 6]

[Formula 7]

[Formula 8]

In Formula 6 to Formula 8,

a is an integer of 1 or 2;

m is an integer from 1 to 100, and n is an integer from 0 to 100.

The polymer may have a weight average molecular weight of 1,000 g/mol to 100,000 g/mol.

The polymer may be included in an amount of 0.1% to 50% by weight based on 100% by weight of the composition for the resist underlayer film.

The composition may further include one or more polymers selected from acrylic resins, epoxy resins, novolak-based resins, glycoluril-based resins, and melamine-based resins.

The composition may further include an additive including a surfactant, a thermal acid generator, a plasticizer, a crosslinking agent, or a combination thereof.

Another embodiment is

Forming a film to be etched on a substrate;

Forming a resist underlayer film by applying a composition for a resist underlayer film according to an embodiment on the etch target film;

forming a photoresist pattern on the resist underlayer film; and

sequentially etching the resist underlayer layer and the etch target layer using the photoresist pattern as an etching mask;

It provides a pattern forming method comprising a.

Forming the photoresist pattern

Forming a photoresist film on the resist underlayer film;

Exposing the photoresist film to light; and

A step of developing the photoresist layer may be included.

The forming of the resist underlayer film may further include heat treatment at a temperature of 100° C. to 500° C. after coating the composition for the resist underlayer film.

The composition for a resist underlayer film according to an embodiment can form an ultra-thin film for a predetermined wavelength such as EUV, has excellent coating properties, planarization properties, and adhesion to a photoresist, and is excellent for solutions used during a lithography process. A resist underlayer film having chemical resistance and a fast etch rate can be provided. Therefore, the composition for a resist underlayer film according to one embodiment or a resist underlayer film prepared therefrom may be advantageously used for forming a fine pattern of a photoresist using a high-energy light source such as EUV.

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 skilled in the art can easily implement the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments set forth 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 such as a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the case where it is "directly on" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly on" another part, it means that there is no other part in between.

Unless otherwise defined herein, 'substituted' means that a hydrogen atom in a 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, an amino group A dino 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, a phosphoric acid group or a salt thereof, a vinyl group, a C1 to C20 alkyl group, a C2 to C20 alkene 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 means substituted with a substituent selected from combinations thereof.

In addition, unless otherwise defined herein, 'hetero' means containing 1 to 10 heteroatoms each independently selected from N, O, S and P.

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

In addition, unless otherwise defined herein, '*' indicates a structural unit of a compound or a connecting point of a compound moiety.

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

The present invention prevents the collapse of the resist pattern during the micro-pattern formation process of photolithography using a short-wavelength light source such as an ArF excimer laser (wavelength 193 nm) or a high-energy ray such as EUV (Extreme ultraviolet; wavelength 13.5 nm), and is coated with an ultra-thin film The present invention relates to a composition for a resist underlayer film capable of reducing an etching process time and improving patterning of a photoresist by improving sensitivity to an exposure light source and light absorption efficiency, and a method of forming a photoresist pattern using such an underlayer film.

Specifically, a composition for a resist underlayer film according to an embodiment includes a polymer including a structural unit represented by Chemical Formula 1, a structural unit represented by Chemical Formula 2, or a combination thereof; and a solvent.

[Formula 1]

In Formula 1,

A is a nitrogen-containing heterocyclic group,

R ¹ and R ² are, each independently, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, a vinyl group, an allyl group, a substituted or unsubstituted C2 to C10 alkynyl group, or a substituted Or an unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted C1 to C10 heteroalkenyl group, a substituted or unsubstituted C1 to C10 heteroalkynyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted A C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C1 to C20 heteroaryl group, or a functional group represented by the following formula K,

* is the point connected to the main chain or end of the polymer,

[Formula K]

In the above formula K,

L ¹ is 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, or a substituted or unsubstituted C2 to C20 heterocycloalkylene group , A substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C1 to C20 heteroarylene group, or a combination thereof,

R ^k is a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C3 to C20 heterocycloalkyl group, A cyclic C6 to C20 aryl group, or a substituted or unsubstituted C1 to C20 heteroaryl group,

a is an integer from 0 to 2;

* is a point connected to A in Formula 1;

[Formula 2]

In Formula 2,

A is a nitrogen-containing heterocyclic group,

L ¹ , L ² and 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, or a substituted Or an unsubstituted C2 to C20 heterocycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C1 to C20 heteroarylene group, or a combination thereof,

a is an integer from 0 to 2;

R ^k is as defined in Formula K above,

* is a point connected to the main chain or terminal of the polymer,

At least one of R ¹ and R ² of the structural units represented by Formula 1 included in the polymer is represented by Formula K, wherein a in Formula K is an integer of 1 or 2, or

At least one of the structural units represented by Chemical Formula 2 included in the polymer is an integer of 1 or 2.

The A may be represented by at least one of Formula A-1 or Formula A-2.

[Formula A-1]

[Formula A-2]

In Formula A-1 and Formula A-2,

* Represents a polymer backbone or a point connected to any one of R ¹ , R ² , and R ^k .

By applying the composition according to one embodiment to the lower part of the photoresist to form a film, the adhesion between the film and the photoresist is improved to prevent the collapse of the resist pattern during the fine patterning process, and sensitivity to an exposure light source is improved Accordingly, the patterning performance and efficiency of the photoresist can be improved. In addition, since the lower layer film can be formed as an ultra-thin film using the composition, there is an advantage in that the time of the etching process can be shortened.

The polymer included in the composition includes a nitrogen-containing heterocyclic group to which a sulfoxide or sulfone functional group is connected. Specifically, the polymer contains a sulfoxide or sulfone functional group, so that the polarity is increased by a sulfur-oxygen double bond (S=O), thereby increasing the interaction between polymer molecules and / or hydrogen bonding between molecules (hydrogen bonding) becomes easy, and as a result, the density of the thin film is improved by increasing the interaction between different structural units in the polymer and / or between polymer molecules, and as a result, a film with a dense structure can be realized, and the upper photoresist Adhesion is improved to prevent pattern collapse.

In addition, the polymer constituting the resist underlayer film composition includes a heteroaromatic compound (eg, isocyanurate-based compound or triazine-based compound) to which a sulfoxide or sulfone group is connected, thereby absorbing light during exposure of the resist underlayer film composition efficiency can be improved.

The polymer has excellent solubility in organic solvents such as propylene glycol methyl ether (PGME) even when polymerized with a relatively high molecular weight. Accordingly, the resist underlayer film composition can exhibit excellent coating properties due to its excellent solubility with the organic solvent.

In addition, since the polymer is stable against organic solvents and heat, when a resist underlayer film is formed using a composition for a resist underlayer film containing the polymer, during a process for forming a photoresist pattern, it is peeled off by solvent or heat, or It is possible to minimize the generation of by-products due to the generation of chemicals, and also minimize the loss of thickness due to the photoresist solvent on the upper side.

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

Therefore, when the resist underlayer film composition according to one embodiment is used, a resist underlayer film with improved adhesion and chemical resistance can be formed, and through this, a faster etching effect can be expected compared to the upper photoresist, and the light absorption efficiency for the exposure light source is improved. It can be improved to improve the patterning performance.

In one embodiment, R ¹ and R ² in Formula 1 are each independently a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, a vinyl group, an allyl group, a substituted or unsubstituted C1 to C10 alkyl group, a C2 to C10 alkynyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a functional group represented by Formula K,

L ¹ in Formula K is a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a combination thereof;

R ^k 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.

In one embodiment, L ¹ , L ² , and L ³ in Formula 2 are each independently a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or a substituted or unsubstituted C1 to C10 alkylene group. may be a C6 to C20 arylene group, or a combination thereof.

In one embodiment, R ¹ and R ² in Formula 1 are each independently an allyl group or a functional group represented by Formula K,

L ¹ of Formula K is a substituted or unsubstituted C1 to C10 alkylene group,

R ^k may be a C1 to C10 alkyl group substituted with a hydroxy group or a thiol group. For example, when R ¹ or R ² in Formula 1 is an allyl group, a branched polymer may be formed by combining with an allyl group of another structural unit represented by Formula 1, thereby forming a more dense lower layer of resist. can form a barrier.

In one embodiment, L ¹ , L ² , and L ³ in Formula 2 may each independently be a substituted or unsubstituted C1 to C10 alkylene group.

In one embodiment, the polymer may include one or more of the structural units represented by Chemical Formulas 2 to 5 below.

[Formula 3]

[Formula 4]

[Formula 5]

In Formulas 3 to 5, a is an integer of 1 or 2,

* is the point connected to the main chain or terminal of the polymer.

Specifically, the polymer may be represented by any one of Formulas 6 to 8 below.

[Formula 6]

[Formula 7]

[Formula 8]

In Formula 6 to Formula 8,

a is an integer of 1 or 2;

m is an integer from 1 to 100, and n is an integer from 0 to 100.

Meanwhile, the polymer may have a weight average molecular weight (Mw) of 1,000 g/mol to 100,000 g/mol. More specifically, the polymer may have a weight average molecular weight of 1,000 g/mol to 50,000 g/mol, or 1,000 g/mol to 30,000 g/mol. By having a weight average molecular weight within the above range, the carbon content of the composition for a resist underlayer film including the polymer and the solubility in a solvent may be adjusted and optimized.

The solvent is not particularly limited as long as it has sufficient solubility or dispersibility for the polymer, but examples include propylene glycol, propylene glycol diacetate, propylene glycol methyl ether acetate, methoxy propanediol, diethylene glycol, diethylene glycol butyl ether, Tri(ethylene glycol) monomethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, ethyl lactate, gamma-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetate amide, methylpyrrolidone, methylpyrrolidinone, methyl 2-hydroxyisobutyrate, acetylacetone, ethyl 3-ethoxypropionate, or combinations thereof.

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

In addition, the composition for a resist underlayer film may further include one or more other polymers selected from acrylic resins, epoxy resins, novolac resins, glycoluril resins, and melamine resins, in addition to the above-mentioned polymers, but is not limited thereto no.

The composition for a resist underlayer film may further include an additive such as a surfactant, a crosslinking agent, a thermal acid generator, a plasticizer, or a combination thereof.

The surfactant may be used to improve coating defects caused by an increase in solid content when forming a resist underlayer film, and for example, alkylbenzenesulfonic acid salts, alkylpyridinium salts, polyethylene glycol, quaternary ammonium salts, and the like may be used. It may, but is not limited thereto.

In addition, the composition for a resist underlayer film may further include a crosslinking agent. The crosslinking agent may be used to further harden the lower layer film by inducing a crosslinking reaction, and examples thereof include melamine-based, substituted urea-based, and polymer-based materials thereof. Preferably, a crosslinking agent having at least two cross-linking substituents, for example methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxy Compounds such as methylated benzoguanamine, methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, or butoxymethylated thiourea may be used. It is not limited to this. 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 a molecule may be used. The crosslinking agent may have, for example, two or more crosslinking sites.

The thermal acid generator is, for example, acidic compounds such as p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonate, salicylic acid, sulfosalicylic acid, citric acid, benzoic acid, hydroxybenzoic acid, naphthalenecarboxylic acid, or/and benzoin Tosylate, 2-nitrobenzyl tosylate, and other organic sulfonic acid alkyl esters may be used, but are not limited thereto.

The plasticizer is not particularly limited, and various known plasticizers may be used. Examples of the plasticizer include low molecular weight compounds such as phthalic acid esters, adipic acid esters, phosphoric acid esters, trimellitic acid esters, and citric acid esters, and compounds such as polyethers, polyesters, and polyacetals. can

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

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 cured through a heat treatment process after coating the above-described composition for a resist underlayer film on, for example, a substrate.

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 for explaining a pattern forming method using a 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 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 pre-cleaned to remove contaminants remaining on the thin film 102 . The thin film 102 may be, for example, a silicon nitride film, a polysilicon film, or a silicon oxide film.

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

Thereafter, a resist underlayer film 104 is formed on the thin film by performing a drying and baking process. The baking treatment may be performed at 100 °C to 500 °C, for example, at 100 °C to 300 °C. Since a more specific 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 film 104 .

Examples of the photoresist include a positive type photoresist containing a naphthoquinonediazide compound and a novolac resin, an acid generator capable of dissociating an acid by exposure, a compound and Chemically amplified positive-type photoresist containing an alkali-soluble resin, chemically-amplified positive-type photoresist containing an alkali-soluble resin having a group capable of imparting a resin having increased solubility in an aqueous alkali solution by decomposition in the presence of an acid generator and an acid A type photoresist etc. are mentioned.

Subsequently, 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 90 °C to 120 °C.

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

Describing an exposure process for exposing the photoresist film 106 as an example, an exposure mask having a predetermined pattern is placed on a mask stage of an exposure apparatus, and the exposure mask ( 110) are sorted. Then, by irradiating the mask 110 with light, a predetermined portion of the photoresist film 106 formed on the substrate 100 selectively reacts with the light transmitted through the exposure mask.

For example, examples of light usable in the exposure process include short-wavelength light such as i-line activating radiation having a wavelength of 365 nm, KrF excimer laser having a wavelength of 248 nm, and 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 layer 106a of the exposed portion has relatively hydrophilicity compared to the photoresist layer 106b of the unexposed portion. Accordingly, the photoresist films of the exposed portion 106a and the unexposed portion 106b have different solubilities.

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 becomes easily soluble 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 developing solution. Specifically, the photoresist pattern 108 is completed by dissolving and removing the photoresist film corresponding to the exposed area using a developing solution such as tetra-methyl ammonium hydroxide (TMAH).

Then, the resist underlayer is etched using the photoresist pattern 108 as an etching mask. The organic layer pattern 112 is formed through the above etching process. The etching may be performed by, for example, dry etching using an etching gas, and the etching gas may be, for example, CHF ₃ , CF ₄ , Cl ₂ , O ₂ or a mixed gas thereof. As described above, since the resist underlayer film formed by the resist underlayer film 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 previously performed exposure process, the thin film pattern ( 114) may have a width of several tens of nm 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 relating to the synthesis of the above-described polymer and the preparation of a composition for a resist underlayer film containing the same. However, the present invention is not technically limited by the following examples.

synthesis example

Synthesis Example 1

(1) 1,3,5-triallyl-1,3,5-triazinane-2,4,6-trione (1,3,5-triallyl-1,3,5- triazinane-2,4,6-trione) 24.9g and 4-mercapto-1-propanol (4-mercapto-1-propanol) 6.4g, AIBN (azobisisobutyronitrile) 2.3g, and N,N-dimethylformamide (N ,N-dimethylformamide) 15.9g is added to prepare a reaction solution, and a condenser is connected. After heating the reaction solution at 80° C. for 10 hours to proceed with the reaction, the reaction solution is cooled to room temperature. Thereafter, the reaction solution was stirred and dropped into a 1L wide mouth bottle containing 800 g of distilled water to form gum, and then dissolved in 80 g of tetrahydrofuran (THF). The dissolved resin solution forms a precipitate with toluene and removes single molecules and low molecules, finally obtaining a polymer (m:n = 8:2 (molar ratio), Mw = 20,000 g/mol) was obtained.

[Formula 6-1]

(2) Then, 15 g of the polymer having the structural unit of Chemical Formula 6-1 is dissolved in 200 g of tetrahydrofuran (THF). After adding 0.3 g of sulfamic acid and 150 g of 70% hydrogen peroxide solution, the mixture was stirred at room temperature for 24 hours to prepare a mixture. The mixture was added to 500 g of distilled water, the polymer was precipitated to dissolve the by-product, and the precipitate was separated from the distilled water layer to obtain a polymer represented by the following formula 6-2 (m:n = 8:2 (molar ratio), Mw = 21,000 g/mol) was prepared. The ratio of a in the polymer represented by Chemical Formula 6-2 is as follows.

[Formula 6-2]

Synthesis Example 2

(1) 1,3,5-triallyl-1,3,5-triazinane-2,4,6-trione (1,3,5-triallyl-1,3,5-triazinane-2,4, 6-trione) instead of 1,3-diallyl-5-(2-hydroxyethyl)-1,3,5-triazinane-2,4,6-trione (1,3-diallyl-5-methyl- 1,3,5-triazinane-2,4,6-trione) 32 g was used, and 1,5-pentane dithiol (1,5 -pentanedithiol) A polymer (Mw = 6,000 g/mol) represented by Formula 7-1 was obtained through the same process as in (1) of Synthesis Example 1 described above except for using 8.6 g.

[Formula 7-1]

(2) Then, 20 g of the polymer having the structural unit of Chemical Formula 7-1 is dissolved in 250 g of tetrahydrofuran (THF). After adding 0.4 g of sulfamic acid and 150 g of 70% hydrogen peroxide solution, the mixture was stirred at room temperature for 24 hours to prepare a mixture. The mixture was added to 500 g of distilled water, the polymer was precipitated to dissolve by-products, and the precipitate was separated from the distilled water layer to prepare a polymer (Mw = 6,500 g/mol) represented by Formula 7-2 below. The ratio of a in the polymer represented by Chemical Formula 7-2 is as follows.

[Formula 7-2]

Synthesis Example 3

(1) 1,3,5-triallyl-1,3,5-triazinane-2,4,6-trione (1,3,5-triallyl-1,3,5-triazinane-2,4, 6-trione) instead of 2,4,6-tris (allyloxy) -1,3,5-triazine (2,4,6-tris (allyloxy) -1,3,5-triazine) 25.0 g A polymer containing a structural unit represented by Chemical Formula 8-1 (m:n = 8:2 (molar ratio), Mw = 18,000 g / mol) was obtained.

[Formula 8-1]

(2) After that, 18 g of the polymer having the structural unit of Chemical Formula 8-1 is dissolved in 250 g of tetrahydrofuran (THF). After adding 0.4 g of sulfamic acid and 200 g of 70% hydrogen peroxide solution, the mixture was stirred at room temperature for 24 hours to prepare a mixture. The mixture was added to 500 g of distilled water, the polymer was precipitated to dissolve the by-product, and the precipitate was separated from the distilled water layer to obtain a polymer represented by the following formula 8-2 (m:n = 8:2 (molar ratio), Mw = 20,000 g/mol) was prepared. The ratio of a in the polymer represented by Chemical Formula 8-2 is as follows.

[Formula 8-2]

Preparation of composition for resist underlayer film

Examples 1 to 3 and Comparative Examples 1 to 3

For each of the polymers represented by Chemical Formulas 6-1 to 8-2 prepared in Synthesis Examples 1 to 3, 0.2 g of the polymer, 0.05 g of PD1174 (TCI; crosslinking agent), and pyridinium p-toluenesulfonate ( Method of completely dissolving 0.005 g of pyridinium p-toluenesulfonate (PTS) in 100 g of a mixed solvent of propylene glycol methyl ether (PGME) and ethyl lactate (EL) (mixing volume ratio = 7:3) Through, as shown in Table 1 below, the compositions for resist underlayer films of Examples 1 to 3 and Comparative Examples 1 to 3 were prepared, respectively.

polymer cross-linking agent thermal acid generator menstruum Example 1 Formula 6-2 PD1174 PPTS PGME/EL Example 2 Formula 7-2 Example 3 Formula 8-2 Comparative Example 1 Formula 6-1 Comparative Example 2 Formula 7-1 Comparative Example 3 Formula 8-1

Membrane density evaluation

After applying the composition for a resist underlayer film according to Examples 1 to 3 and Comparative Examples 1 to 3 on a silicon substrate by a spin-on coating method, heat treatment was performed on a hot plate at 205° C. for 1 minute to form a resist underlayer film with a thickness of about 100 nm. formed.

Subsequently, the density of the resist underlayer film was measured, and the results are shown in Table 2. The density of the resist underlayer film was measured using an X-Ray Diffractometer (Model: X'Pert PRO MPD, manufactured by Panalytical Co. (Netherlands)).

Membrane Density (g/cm ³ ) Example 1 1.55 Example 2 1.58 Example 3 1.51 Comparative Example 1 1.39 Comparative Example 2 1.48 Comparative Example 3 1.22

Referring to Table 2, it can be seen that the films formed using the composition for a resist underlayer film according to Examples 1 to 3 have a higher density than the films formed using the composition for a resist underlayer film according to Comparative Examples 1 to 3. This is presumed to be because the polymers included in the compositions for resist underlayer films according to Examples 1 to 3 contain sulfoxide groups and/or sulfone groups, so that the film density is improved by high hydrogen bonding strength and molecular polarity.

From the results of Table 2, it can be seen that when the compositions for resist underlayer films according to Examples 1 to 3 were used, films having a more dense structure than Comparative Examples 1 to 3 could be formed.

Etch rate evaluation

2 ml each of the compositions for a resist underlayer film according to Examples 1 to 3 and Comparative Examples 1 to 3 were applied on a 12-inch wafer, and then spin coating was performed at 1,500 rpm for 20 seconds using an SVS-MX3000 auto track. Thereafter, it was cured at 205° C. for 60 seconds to form a resist underlayer film. For each of the formed resist underlayer films, etching was performed for 20 seconds under CHF ₃ , CF ₄ , Cl ₂ , and O ₂ gas, and the etched thickness was measured to confirm the etch rate. The results are shown in Table 3 below. entered.

In Table 3, the resultant value of the etching rate was set to the value of Example 1 as the standard (1.0), and the etching rate of the remaining Examples 2 to 3 and Comparative Examples 1 to 3 compared to Example 1 was expressed as a relative ratio.

Relative ratio of etching rate (based on Example 1) Example 1 1.0 Example 2 1.1 Example 3 1.3 Comparative Example 1 0.8 Comparative Example 2 0.8 Comparative Example 3 0.9

As described in Table 3, according to the embodiments of the present invention, it can be seen that the etching rate is significantly improved compared to the comparative example. Therefore, from the results of Table 3, it can be seen that when the compositions for resist underlayer films according to Examples 1 to 3 are used, photoresist patterns having better sensitivity than those of Comparative Examples can be formed.

Exposure characteristics evaluation

The compositions for resist underlayer films prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were applied 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 heat treatment was performed on a hot plate at 110° C. for 1 minute to form a photoresist layer having a thickness of about 60 nm. The photoresist layer was exposed to light with an accelerating 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% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) at 23° C. for 60 seconds and then rinsed in pure water for 15 seconds to form a line and space (L/ A photoresist pattern of S) was formed.

It was confirmed whether or not the photoresist pattern collapsed. Whether or not the photoresist pattern collapsed was observed with a scanning electron microscope (SEM), and good cases were marked as ×, and poor cases (pattern collapse observation) were marked as ○, and the results are shown in Table 4 below.

whether the pattern collapses Example 1 × Example 2 × Example 3 × Comparative Example 1 ○ Comparative Example 2 ○ Comparative Example 3 ○

Referring to Table 4, it can be seen that the photoresist patterns formed using the compositions for resist underlayer films according to Examples 1 to 3 are formed in good patterns compared to the patterns formed using the compositions for resist underlayer films according to Comparative Examples. .

In the foregoing, although specific embodiments of the present invention have been described and shown, the present invention is not limited to the described embodiments, and it is common knowledge in the art 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 Therefore, such modifications or variations should not be individually understood from the technical spirit or viewpoint of the present invention, and modified embodiments should fall within the scope of 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 film pattern 114: thin film pattern

Claims (15)

A polymer comprising a structural unit represented by Formula 1, a structural unit represented by Formula 2, or a combination thereof; And a composition for a resist underlayer film comprising a solvent:
[Formula 1]

In Formula 1,
A is a nitrogen-containing heterocyclic group,
R ¹ and R ² are, each independently, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, a vinyl group, an allyl group, a substituted or unsubstituted C2 to C10 alkynyl group, or a substituted Or an unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted C1 to C10 heteroalkenyl group, a substituted or unsubstituted C1 to C10 heteroalkynyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted A C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C1 to C20 heteroaryl group, or a functional group represented by the following formula K,
* is the point connected to the main chain or end of the polymer,
[Formula K]

In the above formula K,
L ¹ is 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, or a substituted or unsubstituted C2 to C20 heterocycloalkylene group , A substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C1 to C20 heteroarylene group, or a combination thereof,
R ^k is a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 heterocycloalkyl group, a substituted or unsubstituted C3 to C20 heterocycloalkyl group, A cyclic C6 to C20 aryl group, or a substituted or unsubstituted C1 to C20 heteroaryl group,
a is an integer from 0 to 2;
* is a point connected to A in Formula 1;
[Formula 2]

In Formula 2,
A is a nitrogen-containing heterocyclic group,
L ¹ , L ² and 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, or a substituted Or an unsubstituted C2 to C20 heterocycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C1 to C20 heteroarylene group, or a combination thereof,
a is an integer from 0 to 2;
R ^k is as defined in Formula K above,
* is a point connected to the main chain or terminal of the polymer,
At least one of R ¹ and R ² of the structural units represented by Formula 1 included in the polymer is represented by Formula K, wherein a in Formula K is an integer of 1 or 2, or
At least one of the structural units represented by Chemical Formula 2 included in the polymer is an integer of 1 or 2. In paragraph 1,
A composition for a resist underlayer film wherein A is represented by at least one of the following formula A-1 or formula A-2:
[Formula A-1]

[Formula A-2]

In Formula A-1 and Formula A-2,
* Represents a polymer backbone or a point connected to any one of R ¹ , R ² , and R ^k . In paragraph 1,
R ¹ and R ² in Formula 1 are each independently a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, a vinyl group, an allyl group, a substituted or unsubstituted C2 to C10 an alkynyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, or a functional group represented by Formula K above;
L ¹ in Formula K is a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a combination thereof;
R ^k is 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. In paragraph 1,
L ¹ , L ² , and L ³ in Formula 2 are each independently a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or a substituted or unsubstituted C6 to C20 A composition for a resist underlayer film comprising an arylene group or a combination thereof. In paragraph 1,
R ¹ and R ² in Formula 1 are each independently an allyl group or a functional group represented by Formula K,
L ¹ of Formula K is a substituted or unsubstituted C1 to C10 alkylene group,
A composition for a resist underlayer film wherein R ^k is a C1 to C10 alkyl group substituted with a hydroxy group or a thiol group. In paragraph 1,
L ¹ , L ² , and L ³ in Formula 2 are each independently a substituted or unsubstituted C1 to C10 alkylene group. In paragraph 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 3 to 5:
[Formula 3]

[Formula 4]

[Formula 5]

In Formulas 3 to 5, a is an integer of 1 or 2,
* is the point connected to the main chain or terminal of the polymer. In paragraph 1,
The polymer is a composition for a resist underlayer film represented by any one of the following formulas 6 to 8:
[Formula 6]

[Formula 7]

[Formula 8]

In Formula 6 to Formula 8,
a is an integer of 1 or 2;
m is an integer from 1 to 100, and n is an integer from 0 to 100. In paragraph 1,
The weight average molecular weight of the polymer is 1,000 g / mol to 100,000 g / mol composition for a resist underlayer film. In paragraph 1,
The composition for a resist underlayer film, wherein the polymer is included in an amount of 0.1% to 50% by weight based on 100% by weight of the composition for a resist underlayer film. In paragraph 1,
A composition for a resist underlayer film, further comprising at least one polymer selected from acrylic resins, epoxy resins, novolac resins, glycoluril resins, and melamine resins. In paragraph 1,
A composition for a resist underlayer film, further comprising an additive including a surfactant, a thermal acid generator, a plasticizer, a crosslinking agent, or a combination thereof. Forming a film to be etched on a substrate;
Forming a resist underlayer film by applying the composition for a resist underlayer film according to any one of claims 1 to 12 on the etch target film;
forming a photoresist pattern on the resist underlayer film; and
sequentially etching the resist underlayer layer and the etch target layer using the photoresist pattern as an etching mask;
Pattern forming method comprising a. In paragraph 13,
Forming the photoresist pattern
Forming a photoresist film on the resist underlayer film;
Exposing the photoresist film to light; and
A pattern forming method comprising the step of developing the photoresist film. In paragraph 13,
The forming of the resist underlayer film further comprises a step of heat-treating at a temperature of 100° C. to 500° C. after coating the composition for the resist underlayer film.