KR102563288B1 - Resist underlayer composition, and method of forming patterns using the composition - Google Patents

Abstract

a polymer comprising a structure in which a moiety represented by Formula 1 and a moiety represented by Formula 2 are bonded; 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.

The lithographic technique coats a photoresist film on a semiconductor substrate such as a silicon wafer to form a thin film, irradiates activating radiation such as ultraviolet rays through a mask pattern on which a device pattern is drawn, and then develops the obtained 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 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 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.

Provided is a composition for a resist underlayer film that does not cause pattern collapse of the resist even in a fine patterning process, is formed into a thin film, can shorten an etching process time, and improves patterning performance and efficiency by improving sensitivity to an exposure light source.

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

In one embodiment, a polymer comprising a structure in which a moiety represented by Formula 1 and a moiety represented by Formula 2 are bonded; and a solvent for a resist underlayer film.

[Formula 1]

In Formula 1,

Z ¹ and Z ² are each independently a substituted or unsubstituted C6 to C10 arylene group or a substituted or unsubstituted C3 to C10 heteroarylene group;

A ¹ is hydrogen, deuterium, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a vinyl group, an allyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C2 to C20 alkynyl group, A C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted C2 to C20 heteroalkenyl group, a substituted or unsubstituted C3 to C20 heterocyclo an alkyl group, or a substituted or unsubstituted C6 to C20 heteroaryl group, or a combination thereof;

A ² is a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C2 to C10 heteroalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or a substituted or unsubstituted C2 to C20 heterocycloalkylene group or a combination thereof;

R ¹ is hydrogen, heavy hydrogen, a hydroxyl group, a halogen group (-F, -Cl, -Br, -I), an epoxy group, an acrylate group, a carboxyl group, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, vinyl group, allyl group, substituted or unsubstituted C2 to C20 alkynyl group, substituted or unsubstituted C3 to C20 cycloalkyl group, substituted or unsubstituted C1 to C10 heteroalkyl group, substituted or unsubstituted C2 to C20 A C20 heteroalkenyl group, a substituted or unsubstituted C3 to C20 heterocycloalkyl group, or a combination thereof;

It is connected to the point indicated by * in Formula 2 below at the * position in Formula 1;

[Formula 2]

In Formula 2,

R ² is hydrogen, heavy hydrogen, a halogen group, a hydroxyl group, a cyano group, a nitro group, an amino group, an epoxy group, a vinyl group, a (meth)acrylate group, an oxetane group, a thiol group, a carboxyl group, a 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 C6 to C30 aryl group, substituted or unsubstituted C6 to C30 aryl an oxy group, or a combination thereof;

R ³ is any one of hydrogen, heavy hydrogen, and a C1 to C10 alkyl group;

n ¹ is 2 to 100;

Z ¹ and Z ² in Formula 1 are each independently a substituted or unsubstituted C6 to C10 arylene group,

A ¹ is a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a vinyl group, an allyl group, a substituted or unsubstituted C2 to C20 alkynyl group, or a substituted or unsubstituted C3 to C20 cyclo an alkyl group, or a combination thereof;

A ² is a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or a combination thereof;

R ¹ is hydrogen, heavy hydrogen, a hydroxyl group, a halogen group (-F, -Cl, -Br, -I), an epoxy group, an acrylate group, a carboxyl group, a substituted or unsubstituted C1 to C10 alkyl group, a vinyl group, an allyl group, a substituted Or an unsubstituted C3 to C20 cycloalkyl group, or a combination thereof,

R ² in Formula 2 is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C10 cycloalkyl group, a substituted or unsubstituted C1 to C30 thioalkyl group, or a combination thereof;

R ³ may be hydrogen, heavy hydrogen, a C1 to C10 alkyl group, or a combination thereof.

Z ¹ and Z ² in Formula 1 are each independently a substituted or unsubstituted phenylene group,

A ¹ is a vinyl group or an allyl group;

A ² is a substituted or unsubstituted C1 to C6 alkylene group;

R ¹ is a hydroxyl group;

R ² in Formula 2 is a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 thioalkyl group, or a combination thereof;

R ³ may be a C1 to C10 alkyl group.

The moiety represented by Formula 1 may be represented by Formula 1-1 below.

[Formula 1-1]

The polymer may have a weight average molecular weight of 1,000 g/mol to 30,000 g/mol.

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 crosslinking agent, a thermal acid generator, a plasticizer, or a combination thereof.

The solid content of the composition may be 0.1 to 10 wt%.

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 may form an ultra-thin film for a predetermined wavelength such as EUV and at the same time provide a resist underlayer film having excellent coating properties, film density, and sensitivity characteristics. 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 photoresist patterning by improving sensitivity to an exposure light source, 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 having a structure in which a moiety represented by Chemical Formula 1 and a moiety represented by Chemical Formula 2 are bonded; and a solvent.

[Formula 1]

In Formula 1,

Z ¹ and Z ² are each independently a substituted or unsubstituted C6 to C10 arylene group or a substituted or unsubstituted C3 to C10 heteroarylene group;

A ¹ is hydrogen, deuterium, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a vinyl group, an allyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C2 to C20 alkynyl group, A C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted C2 to C20 heteroalkenyl group, a substituted or unsubstituted C3 to C20 heterocyclo an alkyl group, or a substituted or unsubstituted C6 to C20 heteroaryl group, or a combination thereof;

A ² is a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C2 to C10 heteroalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or a substituted or unsubstituted C2 to C20 heterocycloalkylene group or a combination thereof;

R ¹ is hydrogen, heavy hydrogen, a hydroxyl group, a halogen group (-F, -Cl, -Br, -I), an epoxy group, an acrylate group, a carboxyl group, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, vinyl group, allyl group, substituted or unsubstituted C2 to C20 alkynyl group, substituted or unsubstituted C3 to C20 cycloalkyl group, substituted or unsubstituted C1 to C10 heteroalkyl group, substituted or unsubstituted C2 to C20 A C20 heteroalkenyl group, a substituted or unsubstituted C3 to C20 heterocycloalkyl group, or a combination thereof;

It is connected to the point indicated by * in Formula 2 below at the * position in Formula 1;

[Formula 2]

In Formula 2,

R ² is hydrogen, heavy hydrogen, a halogen group, a hydroxyl group, a cyano group, a nitro group, an amino group, an epoxy group, a vinyl group, a (meth)acrylate group, an oxetane group, a thiol group, a carboxyl group, a 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 C6 to C30 aryl group, substituted or unsubstituted C6 to C30 aryl an oxy group, or a combination thereof;

R ³ is any one of hydrogen, heavy hydrogen, and a C1 to C10 alkyl group;

n ¹ is 2 to 100;

By applying the composition according to the embodiment to the lower portion of the photoresist to form a film, the adhesion between the film and the photoresist is improved, and the collapse of the resist pattern can be prevented even during the fine patterning process, and sensitivity to exposure light sources is improved. As it improves, it is possible to improve the patterning performance and efficiency of the photoresist. In addition, since an ultra-thin lower layer film can be formed using the composition, there is an advantage in that the time of the etching process can be shortened.

In the polymer included in the composition, the moiety represented by Formula 1 includes a triazine backbone and an arylene group or a heteroarylene group capable of improving film density. Specifically, in the moiety represented by Formula 1, since Z ¹ and Z ² are each independently a substituted or unsubstituted C6 to C10 arylene group or a substituted or unsubstituted C3 to C10 heteroarylene group, the central triazine By including a structure in which a ring is directly bonded to an arylene group or a heteroarylene group, it has a high electron density due to sp ² -sp ² bonding, and accordingly, a film having a dense structure can be implemented in the form of an ultra-thin film by improving the density of the thin film. In addition, when a resist underlayer film is formed using a resist underlayer film composition including the same, secondary electrons may be additionally generated during the photo process, and the additionally generated secondary electrons affect the photoresist during the photo process. given, the acid generation efficiency can be maximized. Accordingly, the sensitivity of the photoresist may be improved by improving the photo process speed of the photoresist. In addition, by including the triazine skeleton, the etch selectivity is excellent, and energy efficiency can be improved when forming patterns after exposure using high-energy rays such as extreme ultraviolet (EUV; wavelength 13.5 nm) and E-Beam (electron beam).

In addition, the polymer may selectively substitute various functional groups at the R ¹ position of the moiety represented by Formula 1, and accordingly, it is easy to control the adhesion to the photoresist during the process of forming a pattern. Collapse of the pattern can be suppressed, and the film density can be improved by increasing the crosslinking rate, so that excellent chemical resistance can be obtained.

The moiety represented by Formula 2 can improve the solubility of a polymer containing the moiety due to its flexible backbone structure, and the triazine unit and the arylene group or hetero arylene group directly connected thereto can exist in a densely connected form in the polymer. By doing so, it is possible to help the film density and ultra-thin coatability of the resist underlayer film.

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

In one embodiment, Z ¹ and Z ² in Formula 1 are each independently a substituted or unsubstituted C6 to C10 arylene group,

A ¹ is a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a vinyl group, an allyl group, a substituted or unsubstituted C2 to C20 alkynyl group, or a substituted or unsubstituted C3 to C20 cyclo an alkyl group, or a combination thereof;

A ² is a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or a combination thereof;

R ¹ is hydrogen, heavy hydrogen, a hydroxyl group, a halogen group (-F, -Cl, -Br, -I), an epoxy group, an acrylate group, a carboxyl group, a substituted or unsubstituted C1 to C10 alkyl group, a vinyl group, an allyl group, a substituted Or an unsubstituted C3 to C20 cycloalkyl group, or a combination thereof,

R ² in Formula 2 is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C10 cycloalkyl group, a substituted or unsubstituted C1 to C30 thioalkyl group, or a combination thereof;

R ³ may be hydrogen, heavy hydrogen, a C1 to C10 alkyl group, or a combination thereof.

In one embodiment, Z ¹ and Z ² in Formula 1 are each independently a substituted or unsubstituted phenylene group,

A ¹ is a vinyl group or an allyl group;

A ² is a substituted or unsubstituted C1 to C6 alkylene group;

R ¹ is a hydroxyl group;

R ² in Formula 2 is a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 thioalkyl group, or a combination thereof;

R ³ may be a C1 to C10 alkyl group.

In one embodiment, the moiety represented by Formula 1 may be represented by Formula 1-1 below.

[Formula 1-1]

A polymer including a structure in which the moiety represented by Formula 1 and the moiety represented by Formula 2 are bonded may have a weight average molecular weight (Mw) of 1,000 g/mol to 30,000 g/mol. For example, the polymer including the structural unit represented by Formula 1 may have a weight average molecular weight of 2,000 g/mol to 20,000 g/mol, for example, 4,000 g/mol to 15,000 g/mol. Not limited. 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, 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, methyl 2-hydroxyisobutyrate, acetylacetone, ethyl 3-ethoxypropionate, or combinations thereof.

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 crosslinking agent may be included in an amount of 1 to 40 parts by weight, for example, about 2 to 30 parts by weight, for example, about 5 to 20 parts by weight, based on 100 parts by weight of the resist underlayer composition. By including it, solubility and crosslinking properties can be secured without changing the optical properties of the resist underlayer film composition.

The thermal acid generator is, for example, an acidic compound such as p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonic acid, salicylic acid, sulfosalicylic acid, citric acid, benzoic acid, hydroxybenzoic acid, naphthalenecarboxylic acid, or/and benzointosyl rate, 2-nitrobenzyl tosylate, and other organic sulfonic acid alkyl esters may be used, but are not limited thereto. The thermal acid generator may be included in an amount of 0.1 to 20 parts by weight, for example, 0.5 to 10 parts by weight, for example, 1 to 5 parts by weight, based on 100 parts by weight of the resist underlayer film composition. The solubility of the resist underlayer film composition can be improved without changing the optical characteristics.

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 solid content of the composition for the resist underlayer film may be, for example, 0.1 to 10 wt%, such as 0.1 to 5 wt%, or, for example, 0.1 to 3 wt%. The solid content is the total components of the resist underlayer film composition excluding the solvent component. By being included within the above range, the thickness, surface roughness and flatness of the resist underlayer film can be adjusted.

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 mold 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 into 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

50 g of the compound represented by Formula 1a, 0.49 g of azobisisobutyronitrile (AIBN), and 200 g of N,N-dimethylformamide (DMF) were added to a 500ml three-neck round flask, and a condenser was connected. After proceeding the reaction at 80 ° C. for 25 hours, the reaction solution was cooled to room temperature. The reaction solution was dropped while stirring into a 1 L wide mouth bottle containing 800 g of water to form gum, which was then dissolved in 80 g of tetrahydrofuran (THF). In the dissolved resin solution, a precipitate is formed using toluene, and single molecules and low molecules are removed to finally obtain 26 g of a polymer (weight average molecular weight (Mw) = 8,200 g/mol) including a structural unit represented by Formula 1b below. got it

[Formula 1a]

[Formula 1b]

Synthesis Example 2

50 g of the compound represented by Formula 2a, 0.4 g of azobisisobutyronitrile (AIBN), and 200 g of N,N-dimethylformamide (DMF) were added to a 500ml three-neck round flask, and a condenser was connected. After proceeding the reaction at 80 ° C. for 25 hours, the reaction solution was cooled to room temperature. The reaction solution was dropped while stirring into a 1 L wide mouth bottle containing 800 g of water to form gum, which was then dissolved in 80 g of tetrahydrofuran (THF). The dissolved resin solution forms a precipitate using toluene and removes single molecules and low molecules to finally obtain 28 g of a polymer (weight average molecular weight (Mw) = 8,300 g/mol) including a structural unit represented by Formula 2b below. got it

[Formula 2a]

[Formula 2b]

Synthesis Example 3

50 g of the compound represented by Formula 3a, 0.36 g of azobisisobutyronitrile (AIBN), and 200 g of N,N-dimethylformamide (DMF) were added to a 500ml three-neck round flask, and a condenser was connected. After proceeding the reaction at 80 ° C. for 25 hours, the reaction solution was cooled to room temperature. The reaction solution was added dropwise while stirring to a 1 L wide mouth bottle containing 800 g of water to form gum, which was then dissolved in 80 g of tetrahydrofuran (THF). In the dissolved resin solution, a precipitate is formed using toluene, and single molecules and low molecules are removed to finally obtain 25 g of a polymer (weight average molecular weight (Mw) = 8,800 g/mol) including a structural unit represented by Formula 3b below. got it

[Formula 3a]

[Formula 3b]

Preparation of composition for resist underlayer film

Example 1 and Comparative Examples 1 to 2

1 g of the polymers prepared in Synthesis Examples 1 to 3 was added as shown in Table 1 below, and 0.15 g of PL-1174 (TCI Company) and 0.01 g of pyridinium p-toluenesulfonate (PTS) as a crosslinking agent. Total Solid Content (Total Solid Content) , TSC) to be 1%, respectively, the compositions for resist underlayer films according to Example 1 and Comparative Examples 1 and 2 were prepared.

polymer cross-linking agent thermal acid generator menstruum Example 1 Synthesis Example 1 PL-1174 PPTS PGME/EL mixed solvent Comparative Example 1 Synthesis Example 2 Comparative Example 2 Synthesis Example 3

Evaluation of coating uniformity

2 ml each of the compositions prepared in Example 1 and Comparative Examples 1 and 2 were respectively applied on 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, it was cured at 210° C. for 90 seconds to form a thin film having a thickness of 250 Å.

In addition, after further diluting the composition for a lower layer film prepared above, an ultra-thin film having a thickness of 50 Å was formed by spin-coating and curing as described above.

Coating uniformity was measured by measuring the thickness of 51 points along the horizontal axis, and the results are shown in Table 2 below. For coating uniformity, the difference (Å) between the maximum and minimum values of the 51-point thickness measurements was indicated, and the smaller the value, the better the coating uniformity.

Coating uniformity (maximum-minimum value (Å)) @ 250 Å film @ 50 Å film Example 1 3.1 0.7 Comparative Example 1 3.3 0.8 Comparative Example 2 3.3 0.8

Referring to Table 2, in the case of the composition for a resist underlayer film according to Example 1, compared to the composition for a resist underlayer film according to Comparative Examples 1 and 2, it can be confirmed that the coating uniformity has the same or better characteristics.

Membrane density evaluation

The composition for a resist underlayer film according to Example 1 and Comparative Examples 1 and 2 was applied on a silicon substrate by a spin-on coating method, and then heat-treated on a hot plate at 210 ° C. for 90 seconds to form a resist underlayer film with a thickness of about 100 nm. did

Subsequently, the density of the resist underlayer film was measured, and the results are shown in Table 3. The density of the resist underlayer was measured using an X-Ray Diffractometer (Model: X'Pert PRO MPD, manufactured by Panalytical Co. (Netherlands)).

Membrane Density (g/cm ³ ) Example 1 1.43 Comparative Example 1 1.42 Comparative Example 2 1.43

Referring to Table 3, it can be seen that the film formed using the composition for a resist underlayer film according to Example 1 has a film density equal to that of the film formed using the composition for a resist underlayer film according to Comparative Examples 1 and 2.

Exposure characteristics evaluation

The compositions prepared in Example 1 and Comparative Examples 1 and 2 were applied by a spin-on coating method, respectively, and then heat-treated on a hot plate at 210° C. for 90 seconds 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. 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 TMAH at 23° C. and then rinsed in pure water for 15 seconds to form a line and space (L/S) photoresist pattern.

Next, the optimal exposure amount of the photoresist pattern was evaluated, and the results are shown in Table 4. Here, the exposure amount for resolving the line and space of 100 nm by 1:1 is referred to as the optimum energy (Eop, μC/cm 2 ), and the values in the table below are expressed as relative values compared to the Eop of Comparative Example 1.

Eop (μC/cm2) Example 1 285 comparative example 300 comparative example 295

Referring to Table 4, when the resist underlayer film was formed using the composition for a photoresist underlayer film according to Example 1, it could be confirmed that the optimal exposure amount of the photoresist pattern was excellent compared to Comparative Examples 1 and 2.

Therefore, from the results of Table 4, it can be seen that when the composition for a resist underlayer film according to Example 1 is used, a photoresist pattern having a higher sensitivity than that of the comparative example can be formed.

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 (11)

a polymer comprising a structure in which a moiety represented by Formula 1 and a moiety represented by Formula 2 are bonded; and
menstruum
A composition for a resist underlayer film comprising:
[Formula 1]

In Formula 1,
Z ¹ and Z ² are each independently a substituted or unsubstituted C6 to C10 arylene group or a substituted or unsubstituted C3 to C10 heteroarylene group;
A ¹ is hydrogen, deuterium, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a vinyl group, an allyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C2 to C20 alkynyl group, A C3 to C20 cycloalkyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C1 to C10 heteroalkyl group, a substituted or unsubstituted C2 to C20 heteroalkenyl group, a substituted or unsubstituted C3 to C20 heterocyclo an alkyl group, or a substituted or unsubstituted C6 to C20 heteroaryl group, or a combination thereof;
A ² is a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C2 to C10 heteroalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or a substituted or unsubstituted C2 to C20 heterocycloalkylene group or a combination thereof;
R ¹ is hydrogen, heavy hydrogen, a hydroxyl group, a halogen group (-F, -Cl, -Br, -I), an epoxy group, an acrylate group, a carboxyl group, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, vinyl group, allyl group, substituted or unsubstituted C2 to C20 alkynyl group, substituted or unsubstituted C3 to C20 cycloalkyl group, substituted or unsubstituted C1 to C10 heteroalkyl group, substituted or unsubstituted C2 to C20 A C20 heteroalkenyl group, a substituted or unsubstituted C3 to C20 heterocycloalkyl group, or a combination thereof;
It is connected to the point indicated by * in Formula 2 below at the * position in Formula 1;
[Formula 2]

In Formula 2,
R ² is hydrogen, heavy hydrogen, a halogen group, a hydroxyl group, a cyano group, a nitro group, an amino group, an epoxy group, a vinyl group, a (meth)acrylate group, an oxetane group, a thiol group, a carboxyl group, a 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 C6 to C30 aryl group, substituted or unsubstituted C6 to C30 aryl an oxy group, or a combination thereof;
R ³ is any one of hydrogen, heavy hydrogen, and a C1 to C10 alkyl group;
n ¹ is 2 to 100; In paragraph 1,
Z ¹ and Z ² in Formula 1 are each independently a substituted or unsubstituted C6 to C10 arylene group,
A ¹ is a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a vinyl group, an allyl group, a substituted or unsubstituted C2 to C20 alkynyl group, or a substituted or unsubstituted C3 to C20 cyclo an alkyl group, or a combination thereof;
A ² is a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or a combination thereof;
R ¹ is hydrogen, heavy hydrogen, a hydroxyl group, a halogen group (-F, -Cl, -Br, -I), an epoxy group, an acrylate group, a carboxyl group, a substituted or unsubstituted C1 to C10 alkyl group, a vinyl group, an allyl group, a substituted Or an unsubstituted C3 to C20 cycloalkyl group, or a combination thereof,
R ² in Formula 2 is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C10 cycloalkyl group, a substituted or unsubstituted C1 to C30 thioalkyl group, or a combination thereof;
R ³ is hydrogen, heavy hydrogen, a C1 to C10 alkyl group, or a combination thereof. In paragraph 1,
Z ¹ and Z ² in Formula 1 are each independently a substituted or unsubstituted phenylene group,
A ¹ is a vinyl group or an allyl group;
A ² is a substituted or unsubstituted C1 to C6 alkylene group;
R ¹ is a hydroxyl group;
R ² in Formula 2 is a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 thioalkyl group, or a combination thereof;
The composition for a resist underlayer film, wherein R ³ is a C1 to C10 alkyl group. In paragraph 1,
A composition for a resist underlayer film wherein the moiety represented by Formula 1 is represented by Formula 1-1 below:
[Formula 1-1]
In paragraph 1,
The weight average molecular weight of the polymer is 1,000 g / mol to 30,000 g / mol 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 crosslinking agent, a thermal acid generator, a plasticizer, or a combination thereof. In paragraph 1,
A composition for a resist underlayer film wherein the solid content of the composition is 0.1 to 10 wt%. 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 8 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 9,
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 9,
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.