KR20150077949A - Method for forming pattern using anti-reflective coating composition comprising photoacid generator - Google Patents

Abstract

A method for forming a pattern by a negative tone develop (NTD) forms an anti-reflective coating composition layer including a photo acid generator between a substrate and a photoresist composition layer and more activates deblocking of the photoresist composition layer in light exposure, thereby preventing a falling phenomenon of the developed pattern and improving a minimum linewidth characteristic of the pattern.

Description

FIELD OF THE INVENTION The present invention relates to a pattern forming method using an antireflective coating composition comprising a photoacid generator,

The present invention relates to a pattern formation method by negative tone development (NTD) in a photolithography process.

Photoresist is a photosensitive composition used to transfer an image to a substrate. A coating layer of photoresist is formed on the substrate and exposed to actinic radiation through a photomask. The photomask has an opaque region and a transparent region in the active radiation. Upon exposure to actinic radiation, the photoresist coating layer undergoes a chemical modification of the photoluminescence, thereby transferring the pattern of the photomask to the photoresist coating layer. The photoresist coating layer is then developed to produce a patterned image that is capable of selective treatment of the substrate.

Positive tone chemically amplified photoresists typically comprise a resin having an acid-labile leaving group and a photoacid generator. When exposed to a chemical radiation, the acid generator forms an acid, which causes cleavage of acid-labile groups in the resin during post-exposure bake. This results in a difference in solubility characteristics between the exposed region and the non-exposed region in an aqueous alkali developer or a hydrophobic organic solvent developer. The exposed area of the resist is soluble in an aqueous alkaline developer and insoluble in a hydrophobic organic developer. In the case of the positive tone process in the manufacture of semiconductor devices, only the photoresist in the non-exposed region is left on the substrate in the aqueous alkaline developer solution, and in the case of the negative tone process, the photoresist in the exposed region is treated with the hydrophobic organic developer, It remains.

Photoresists are used in semiconductor fabrication to convert a semiconductor slice, such as Si or GaAs, to a complex matrix of electronic conduction paths (preferably micron or submicron geometry) that perform circuit functions. In order to achieve this purpose, it is important to properly treat the photoresist. While the various steps for photoresist processing work interdependently with each other, one of the most important steps in achieving a high resolution photoresist image is the exposure step.

When the active radiation irradiated to the photoresist coating layer is reflected in such an exposure step, the resolution of the patterned image in the photoresist coating layer may be degraded. For example, when the active radiation is reflected from the interface between the substrate and the photoresist, a spatial variation occurs in the intensity of the active radiation irradiated on the photoresist coating layer, and the active radiation is scattered into the unintended photoresist region, Can be changed or become heterogeneous. In addition, the amount of active radiation scattered or reflected differs from region to region, so that the line width may become more uneven and may cause a problem that the resolution is lowered according to, for example, the topography of the substrate.

In order to solve such a reflection problem, a light absorption layer, that is, an antireflection coating layer is used between the substrate surface and the photoresist coating layer (see U.S. Patent Nos. 5,939,236, 5,886,102, 5,851,738, 5,851,730, etc.) .

However, when such a conventional antireflection coating layer is used in a lithography process using negative tone development (NTD), a pattern collapse phenomenon can easily occur at the time of developing a narrow line width pattern (40 nm or less) There is a problem that the quality is lowered or the process margin is not sufficiently ensured and the yield is lowered.

U.S. Patent No. 5,939,236 U.S. Patent No. 5,886,102 U.S. Patent No. 5,851,738 U.S. Patent No. 5,851,730

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a pattern forming method using a negative tone phenomenon using an antireflection coating layer which can solve the conventional problems as described above.

According to the above object, the present invention provides a method for manufacturing a light emitting device, comprising the steps of: (1) forming a layer of an antireflective coating composition comprising (a) an organic polymer, (b) a photoacid generator, and (c) a crosslinking agent; (2) forming a layer of a photoresist composition on the antireflective coating composition layer; (3) exposing the photoresist composition layer and the antireflective coating composition layer simultaneously to active radiation and then baking; And (4) developing the exposed photoresist composition layer with an organic solvent developer.

The method of pattern formation by negative tone development of the present invention is characterized by forming and performing a layer of antireflective coating composition comprising a photoacid generator between the substrate and the photoresist composition layer to form a deblocking (de -blocking can be further activated to prevent the pattern collapse and to improve the line CD characteristic of the pattern.

Figure 1 shows the results of applying the antireflective coating compositions prepared in Comparative Examples 1 and 2 and Example 1 to a photolithography process of negative tone development (NTD) and measuring the line / space pattern developed in the photoresist composition layer Was observed with an electron microscope.

Antireflective coating compositions used in Negative Tone Development (NTD)

The anti-reflective coating composition used in the pattern formation method by negative tone development (NTD) of the present invention comprises (a) an organic polymer, (b) a photoacid generator, and (c) a crosslinking agent.

(a) an organic polymer

Wherein the organic polymer comprises at least one structural unit derived from a cyanurate compound having at least two functional groups selected from (a-1) carboxy and carboxyester; And (a-2) at least one structural unit derived from a diol or a polyol-based compound.

The structural unit (a-1) may be, for example, at least one structural unit derived from a compound represented by the following general formula (1)

[Chemical Formula 1]

In this formula,

At least two of R ¹ OOC (CX ₂ ) _n -, R ² - and R ³ OOC (CX ₂ ) _m - functional groups are acid or ester groups;

R ^1, R ^2, R ³ and each X are each independently hydrogen or non-hydrogen substituent, for example, substituted or unsubstituted C _1-10 alkyl, substituted or unsubstituted C _2-10 alkenyl or C _{2- 10} alkynyl group (e.g., allyl and the like), substituted or unsubstituted C _1-10 alkanoyl, substituted or unsubstituted C _1-10 alkoxy (e.g., methoxy, propoxy, butoxy, etc.), epoxy, substituted or Substituted or unsubstituted C _1-10 alkylthio, substituted or unsubstituted C _1-10 alkylsulfinyl, substituted or unsubstituted C _1-10 alkylsulfonyl, substituted or unsubstituted carboxy, substituted or unsubstituted -COO -C _1-8 alkyl, substituted or unsubstituted C _6-12 aryl: a cyclic (for example, phenyl, naphthyl, etc.), or a substituted or unsubstituted 5- to 10-membered heterocyclic Ali or heteroaryl group (e.g. Methylphthalimide, N-methyl-1,8-phthalimide);

n and m are the same or different and each is an integer greater than zero.

The structural unit (a-2) may be at least one structural unit derived from, for example, a diol, triol or tetraol.

Specific examples of the diol include ethylene glycol; 1,3-propanediol; 1,2-propanediol; 2,2-dimethyl-1,3-propanediol; 2,2-diethyl-1,3-propanediol; 2-ethyl-3-methyl-1,3-propanediol; 2-methyl-2-propyl-1,3-propanediol; 2-butyl-2-ethyl-1,3-propanediol; 1,4-butanediol; 2-methyl-1,4-butanediol; 1,2-butanediol; 1,3-butanediol; 2,3-butanediol; 2,3-dimethyl-2,3-butanediol; 1,5-pentanediol; 1,2-pentanediol; 2,4-pentanediol; 2-methyl-2,4-pentanediol; 1,6-hexanediol; 2,5-hexanediol; 1,2-hexanediol; 1,5-hexanediol; 2-ethyl-1,3-hexanediol; 2,5-dimethyl-2,5-hexanediol; 1,7-heptanediol; 1,8-octanediol; 1,2-octanediol; 1,9-nonanediol; 1,10-decanediol; 1,2-decanediol; 1,12-dodecanediol; 1,2-dodecanediol; 1,2-tetradecanediol; 1,2-hexadecanediol; 1,16-hexadecanediol; 1,2-cyclobutane dimethanol; 1,4-cyclohexanedimethanol; 1,2-cyclohexanedimethanol; 5-norbornene-2,2-dimethanol; 3-cyclohexene-1,1-dimethanol; Dicyclohexyl-4,4'-diol; 1,2-cyclopentanediol; 1,3-cyclopentanediol; 1,2-cyclooctanediol; 1,4-cyclooctanediol; 1,5-cyclooctanediol; 1,2-cyclohexanediol; 1,3-cyclohexanediol; 1,4-cyclohexanediol; 1,2-cycloheptanediol; 2,2,4,4-tetramethyl-l, 3-cyclobutanediol; 1,2-cyclododecanediol; Decahydronaphthalene-1,4-diol; Decahydronaphthalene-1,5-diol; 3-chloro-1,2-propanediol; 1,4-dibromobutane-2,3-diol; 2,2,3,3-tetrafluoro-1,4-butanediol; Diethylene glycol; Triethylene glycol; Tetraethylene glycol; Pentaethylene glycol; Dipropylene glycol; Isobarbide; Isomannide; 1,3-dioxane-5, 5-dimethanol; 1,4-dioxane-2,3-diol; 1,4-diethane-2,5-diol; 1,2-dithiane-4,5-diol; 2-hydroxyethyl disulfide; 3,6-dithia-1,8-octanediol; 3,3'-thiodipropanol; 2,2'-thiodiethanol; 1,3-hydroxyacetone; 1,5-dihydroxy-2,2,4,4-tetrachloro-3-pentanone; Glyceraldehyde; Benzopinacol; 1,1,4,4-tetraphenyl-1,4-butanediol; 3,4-bis (p-hydroxyphenol) -3,4-hexanediol; 1,2-benzene dimethanol; 1,4-benzene dimethanol; 2,3,5,6-tetramethyl-p-xylene -?,? '- diol; 2,4,5,6-tetrachlorobenzene-1,3-dimethanol; 2,3,5,6-tetrachlorobenzene-1,4-dimethanol; 2,2-diphenyl-1,3-propanediol; 3- (4-chlorophenoxy) -1,2-propanediol; 2,2 '- (p-phenylenedioxy) -diethanol; 5-nitro-m-xylene -?,? '- diol; 1,8-bis (hydroxymethyl) naphthalene; 2,6-bis (hydroxymethyl) -p-cresol; O, O'-bis (2-hydroxyethyl) benzene; 1,2-O-isopropylidenecylsulfuronos; 5,6-isopropylidene ascorbic acid; 2,3-O-isopropylidene stearate, and the like.

Specific examples of the triols include glycerol; 1,1,1-tris (hydroxymethyl) ethane; 2-hydroxymethyl-1,3-propanediol; 2-ethyl-2- (hydroxymethyl) -1,3-propanediol; 2-hydroxymethyl-2-propyl-1,3-propanediol; 2-hydroxymethyl-l, 4-butanediol; 2-hydroxyethyl-2-methyl-l, 4-butanediol; 2-hydroxymethyl-2-propyl-l, 4-butanediol; 2-ethyl-2-hydroxyethyl-1,4-butanediol; 1,2,3-butanetriol; 1,2,4-butanetriol; 3- (hydroxymethyl) -3-methyl-1,4-pentanediol; 1,2,5-pentanetriol; 1,3,5-pentanetriol; 1,2,3-trihydroxyhexane; 1,2,6-trihydroxyhexane; 2,5-dimethyl-1,2,6-hexanetriol; Tris (hydroxymethyl) nitromethane; 2-methyl-2-nitro-1,3-propanediol; 2-bromo-2-nitro-1,3-propanediol; 1,2,4-cyclopentanetriol; 1,2,3-cyclopentanetriol; 1,3,5-cyclohexanetriol; 1,3,5-cyclohexane trimethanol; 1,3,5-tris (2-hydroxyethyl) cyanuric acid; 1,2-O-isopropylideneidopuranos; 1,2-O-isopropylidene glucopuranos; Methyl xylopyranoside; And croconic acid.

Specific examples of the tetraol include 1,2,3,4-butanetetrol; 2,2-bis (hydroxymethyl) -1,3-propanediol; 1,2,4,5-pentanetetrol; Tetrahydroxy-1,4-benzoquinone; alpha -methyl mannopyranoside; 2-deoxygalactose; 3-O-methylglucose; Ribose; Xylose, and the like.

The organic polymer may be contained in an amount of 70.0 to 95.0% by weight, based on the weight of the solid content of the antireflective coating composition. More specifically, the content of the organic polymer may be 78 to 90% by weight.

(b)

The photoacid generator is not particularly limited, and one type of photoacid generator or a mixture of two or more species can be used.

The photoacid generators may include, for example, onium salts, nitrobenzyls, sulfonic acid esters, diazomethane, glyoxime, N-hydroxyimide sulfonic acid esters, Generator is possible.

The onium salt photoacid generator may be a sulfonate and a sulfonium salt having an aromatic group. Specific examples of the onium salt-based photoacid generators include triphenylsulfonium trifluoromethane sulfonate, (pt-butoxyphenyl) diphenylsulfonium trifluoromethane sulfonate, tris (pt-butoxyphenyl) sulfonium tri Fluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate, and the like.

Specific examples of the nitrobenzyl photoacid generator include 2-nitrobenzyl-p-toluene sulfonate, 2,6-dinitrobenzyl-p-toluene sulfonate, 2,4-dinitrobenzyl- . Specific examples of the sulfonic acid ester-based photoacid generators include 1,2,3-tris (methanesulfonyloxy) benzene, 1,2,3-tris (trifluoromethanesulfonyloxy) benzene, 1,2,3 -Tris (p-toluenesulfonyloxy) benzene, and the like. Specific examples of the diazomethane-based photoacid generators include bis (benzenesulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, and the like. Specific examples of the glyoxime-based photoacid generator include bis-O- (p-toluenesulfonyl) -? - dimethylglyoxime, bis-O- (n-butanesulfonyl) have. Specific examples of the N-hydroxyimide sulfonic acid ester-based photoacid generators include N-hydroxysuccinimide methanesulfonic acid ester and N-hydroxysuccinimide trifluoromethanesulfonic acid ester. Specific examples of the halothiazine type photo acid generator include 2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- ) -4,6-bis (trichloromethyl) -1,3,5-triazine.

The photoacid generator may be contained in an amount of 0.01 to 15% by weight, based on the weight of the solid content of the antireflective coating composition. More specifically, the content of the photoacid generator may be 3 to 10% by weight.

(c) a crosslinking agent

The crosslinking agent component is not particularly limited as long as it is a compound capable of causing a crosslinking reaction by light and / or heat, and is preferably a compound capable of causing a crosslinking reaction by heat.

The crosslinking agent component cures, crosslinks or cures when exposed to acid when the photoacid generator is exposed to active radiation.

Preferred cross-linking agents include amine-based materials such as melamine-based, glycoluril-based, benzoguanamine-based, and urea-based cross-linking agents. Examples of the melamine crosslinking agent include melamine-formaldehyde resins.

Such cross-linking agents are commercially available, for example melamine-based cross-linking agents sold under the trade names Cymel 300, 301 and 303 by American Cyanamid; The glycoluril crosslinking agent is sold by American Cyanamid under the trade designation Cymel 1170, 1171, 1172; Urea crosslinking agents are sold by American Cyanamid under the trade names Beetle 60, 65 and 80; Benzoguanamine-based crosslinking agents are sold under the trade names Cymel 1123 and 1125 by American Cyanamid.

The crosslinking agent may be contained in an amount of 1 to 20% by weight based on the weight of the solid content of the antireflective coating composition. More specifically, the content of the crosslinking agent may be 5 to 15% by weight.

(d) Thermal acid generator

The anti-reflective coating composition for NTD may further include a thermal acid generator.

The thermal acid generator may promote or enhance the crosslinking reaction during curing of the antireflective composition coating layer.

Further, the thermal acid generator may be ionic or substantially neutral.

As an example, the thermal acid generator may be an arnesulfonic acid thermal acid generator, and more specifically, a benzene sulfonic acid thermal acid generator.

The thermal acid generator may be contained in an amount of 0.1 to 2.0% by weight, based on the weight of the solid content of the antireflective coating composition. More specifically, the content of the thermal acid generator may be 0.5 to 1.0 wt%.

(e) Solvent

The antireflective coating composition may comprise a solvent.

Specific examples of the solvent include oxybutyric acid esters such as methyl 2-hydroxyisobutyrate, ethyl lactate and the like; Glycol ethers such as 2-methoxyethyl ether, ethylene glycol monomethyl ether and propylene glycol monomethyl ether; Ethers having a hydroxyl group such as methoxybutanol, ethoxybutanol, methoxypropanol, ethoxypropanol and the like; Esters such as methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate and the like; Dibasic esters; Propylene carbonates; Gamma-butyrolactones, and the like.

The solvent may be included in the composition such that the solids concentration of the antireflective coating composition is from 0.1 to 2.0% by weight. More specifically, the solvent may be included in the composition such that the solids concentration of the antireflective coating composition is from 0.7 to 1.0% by weight.

Method for pattern formation by negative tone development (NTD)

The method of pattern formation by negative tone development (NTD) of the present invention comprises the steps of (1) forming a layer of an antireflective coating composition comprising (a) an organic polymer, (b) a photoacid generator, and (c) step; (2) forming a layer of a photoresist composition on the antireflective coating composition layer; (3) exposing the photoresist composition layer and the antireflective coating composition layer simultaneously to active radiation and then baking; And (4) developing the exposed photoresist composition layer with an organic solvent developer.

Step (1): Formation of antireflective coating composition layer

This step is a step of forming a layer of antireflective coating composition on a substrate.

The specific composition of the antireflection coating composition used in this step is as described above, and may be prepared by mixing the raw materials including the organic polymer, the photoacid generator, and the crosslinking agent in an appropriate amount.

The antireflective coating composition can be applied on a substrate by various methods such as spin coating. The antireflective coating composition may be applied at a dry thickness of from 2.0 nm to 50.0 nm and preferably at a dry thickness of from 5.0 nm to 30.0 nm.

Preferably, the applied anti-reflective coating composition layer can be cured. The curing conditions may vary depending on the components of the antireflective coating composition, but may be, for example, from 80 ° C to 225 ° C and from 0.5 minute to 40 minutes. This curing may prevent the layer of antireflective coating composition from substantially dissolving in the photoresist solvent and the alkali developing aqueous solution.

The antireflective coating composition layer may be formed of a single layer or a plurality of layers. For example, a layer of a second antireflective coating composition different from the antireflective coating composition layer may be pre-formed on the substrate such that the antireflective coating composition layer is coated on the second antireflective coating composition layer .

Through the formation of such an antireflective coating composition layer, it is possible to prevent the substrate from reflecting the incident light during exposure of the photoresist composition layer to deteriorate the quality of the pattern, and in particular to prevent deblocking of the photoresist composition layer de-blocking may be further activated to prevent the pattern collapse and to improve the line CD characteristic of the pattern. The anti-reflective coating composition layer may also improve the depth of focus, exposure tolerance, line width uniformity, and the like.

The substrate may comprise one or more layers.

The at least one layer constituting the substrate may be, for example, a conductive layer such as an aluminum layer, a copper layer, a molybdenum layer, a tantalum layer, a titanium layer, a tungsten layer, or an alloy layer of these metals; A nitride layer or a silicide layer; A doped amorphous silicon layer or a doped polysilicon layer; A dielectric layer such as a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer, or a metal oxide layer; A semiconductor layer such as single crystal silicon; Glass layer; Quartz layer; These may include a combined or mixed layer or the like.

The one or more layers constituting the substrate may also be patterned, for example, chemical vapor deposition (CVD) such as plasma-enhanced CVD, low pressure CVD or epitaxial growth; Physical vapor deposition (PVD) such as sputtering or evaporation; Electroplating, and the like.

The substrate may be provided with a hard mask layer. The hardmask layer may be provided, for example, when the layer to be etched with a very thin resist layer requires a considerable etch depth or the resist selectivity of the etchant is low. The hard mask layer may be used as a mask for etching the substrate after the resist pattern is transferred.

The material of the hard mask is not particularly limited and may be, for example, tungsten, titanium, titanium nitride, titanium oxide, zirconium oxide, aluminum oxide, aluminum oxynitride, hafnium oxide, amorphous carbon, Rid, silicon nitride, silicon-organic hybrid materials, and the like.

The hard mask layer may be formed, for example, by chemical or physical vapor deposition or spin coating. The hardmask layer may be comprised of a single layer or a plurality of different layers.

Step (2): Formation of photoresist composition layer

A photoresist composition layer is formed on the antireflective coating layer.

The photoresist composition may include a matrix polymer, a photo acid generator, and a solvent.

The matrix polymer may comprise at least one unit having an acid-cleavable protecting group.

Examples of the acid-cleavable protecting group include an acyclic tricyclic alkyl carbon (e.g., t-butyl) or an alicyclic tertiary carbon (e.g., methyladamantyl) covalently bonded to the carboxyl oxygen of the ester of the matrix polymer, Lt; / RTI > or an ester group is possible.

The unit that the matrix polymer may contain may be, for example, a unit derived from (alkyl) acrylate, preferably a unit derived from an acid-cleavable (alkyl) acrylate, and specifically, t- , t-butyl methacrylate, methyladamantyl acrylate, methyladamantyl methacrylate, ethylphenchyl acrylate, ethylpentyl methacrylate, and the like.

Another example of a unit that the matrix polymer may contain is a unit derived from a non-aromatic cyclic olefin such as a substituted norbornene (double bond in the ring). Another example of the unit that the matrix polymer may contain is a unit derived from an anhydride, for example, a unit derived from maleic anhydride, itaconic anhydride, and the like.

The matrix polymer may include a unit containing a heteroatom such as oxygen and sulfur. For example, the heteroalicyclic unit may be included in the main chain of the matrix polymer.

In addition, such a matrix polymer may be used as two or more kinds of blends.

Such a matrix polymer is commercially available or can be easily produced by a person skilled in the art.

The matrix polymer may be included in the photoresist composition in an amount sufficient to enable the exposed areas of the photoresist to be developed in a suitable developer solution and may be included in an amount of, for example, 50 to 95 wt% based on the solids content of the photoresist composition have.

The weight average molecular weight (Mw) of the matrix polymer may be less than 100,000, and may be, for example, 5000 to 100,000, more specifically 5000 to 15,000.

The photoresist composition may also include a photoactive component to produce a latent image in the coating layer of the composition when exposed to actinic radiation, and may in particular comprise a photoacid generator. As the photo-acid generator, a kind similar to that described above in the antireflection coating composition may be used.

The photoresist composition may include a solvent, and examples thereof include glycol ethers such as 2-methoxyethyl ether, ethylene glycol monomethyl ether and propylene glycol monomethyl ether; Propylene glycol monomethyl ether acetate; Lactates such as methyl lactate and ethyl lactate; Propionates such as methyl propionate, ethyl propionate, ethyl ethoxypropionate and methyl-2-hydroxyisobutyrate; Methyl cellosolve acetate; Aromatic hydrocarbons such as toluene and xylene; And ketones such as acetone, methyl ethyl ketone, cyclohexanone, and 2-heptanone. The solvent may be included as one or a mixture of two or more solvents.

The photoresist composition may be applied on the antireflective coating composition layer by spin coating, dipping, roller coating or other conventional coating methods. Preferably, spin coating can be used and the solids content in the coating solution can be adjusted to the desired film thickness depending on the particular coating equipment used, the viscosity of the solution, the speed of the coating equipment and the time allowed for spinning.

The thickness of the photoresist composition layer may be, for example, from 50 nm to 300 nm.

Next, the photoresist composition layer is soft baked to minimize the solvent content in the layer and create tack-free of the layer to the substrate. The soft bake can be performed in a hot plate or in an oven. The soft bake time and temperature may vary depending on the specific material and thickness of the photoresist. For example, the soft bake may be performed at a temperature of 90 DEG C to 150 DEG C for about 30 seconds to 90 seconds.

An overcoat layer may be further formed on the photoresist composition layer. The overcoat layer can be formed for the purpose of homogenizing the resist pattern, reducing the reflectance at the time of resist exposure, improving the focus tolerance range, improving the allowable exposure range, and reducing defects. An overcoat layer may be formed by spin coating the overcoat composition. The solids content in the coating solution can be adjusted to provide the desired film thickness depending on the particular coating device used, the viscosity of the solution, the speed of the coating equipment, and the time allowed for spinning. The overcoat layer may have a thickness of 200 ANGSTROM to 1000 ANGSTROM.

The formed overcoat layer can minimize the solvent content in the overcoat layer through the bake. The bake can be carried out on a hot plate or in an oven. A typical bake may be performed at a temperature of about 80 < 0 > C to 120 < 0 > C for about 30 seconds to 90 seconds.

Step (3): In the exposure step

The photoresist composition layer is then exposed to actinic radiation through a photomask to produce a difference in solubility between the exposed and unexposed regions.

The photomask has an optically transparent region and an optically opaque region.

The exposure wavelength may be, for example, 400 nm or less, 300 nm or less, or 200 nm or less, preferably 248 nm (e.g., KrF excimer laser light) or 193 nm (e.g. ArF excimer laser light).

The exposure energy may be about 10 to 80 mJ / cm < ² >, depending on the composition of the exposure equipment and photosensitive composition.

After exposing the photoresist composition layer, a post exposure bake (PEB) is performed.

The PEB can be performed, for example, in a hot plate or in an oven. The conditions of PEB may vary depending on the composition and thickness of the photoresist composition layer. For example, the PEB may be performed at a temperature of 80 [deg.] C to 150 [deg.] C for 30 seconds to 90 seconds.

Whereby a latent image is formed in the photoresist composition layer along the boundary between the exposed region and the unexposed region.

Step (4): Developing step

The overcoat layer and the exposed photoresist composition layer are then developed to remove unexposed areas of the photoresist composition layer to form a pattern in the photoresist composition layer.

The developer may generally be an organic solvent developer and may include an organic solvent selected from ketones, esters, ethers, amides, hydrocarbons, and mixtures thereof.

Specific examples of the ketone include acetone, 2-hexanone, 5-methyl-2-hexanone, 2-heptanone, 4-heptanone, 1-octanone, Diisobutyl ketone, cyclohexanone, methylcyclohexanone, phenylacetone, methylethylketone, methylisobutylketone, and the like. Specific examples of the esters include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate , Butyl lactate, propyl lactate, and the like. Specific examples of the ethers include dioxane, tetrahydrofuran, glycol ethers (e.g., ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, Triethylene glycol monoethyl ether, methoxymethylbutanol), and the like. Specific examples of the amide include N-methyl-2-pyrrolidone, N, N-dimethylacetamide and N, N-dimethylformamide. Specific examples of the hydrocarbons include aromatic hydrocarbon solvents (e.g., toluene and xylene).

The developer may include a solvent used in a photoresist composition, for example, 2-heptanone, butyl acetate (e.g., n-butyl acetate) and the like.

The developer may also comprise a mixture of these solvents, or a mixture with a solvent other than the solvent or a mixture with water.

For example, the developer may comprise a mixture of a first organic solvent and a second organic solvent. The first organic solvent includes C _4-9 ketones; Hydroxyalkyl esters such as methyl 2-hydroxyisobutyrate and ethyl lactate; And propylene glycol monomethyl ether may be a linear or branched C _5-6 alkoxy alkyl acetate, such as acetate, and this of 2-heptanone or 5-methyl-2-hexanone are preferred. Examples of the second organic solvent include linear or branched C _6-8 alkyl esters such as n-butyl acetate, n-pentyl acetate, n-butyl propionate, n-hexyl acetate, n-butyl butyrate and isobutyl butyrate ; Or a linear or branched C _8-9 ketone such as 4-octanone, 2,5-dimethyl-4-hexanone or 2,6-dimethyl-4-heptanone, among which n-butyl acetate, n -Butyl propionate or 2,6-dimethyl-4-heptanone is preferred. Preferred combinations of the first and second organic solvents are 2-heptanone / n-butyl propionate, cyclohexanone / n-butyl propionate, PGMEA / n-butyl propionate, Heptanone / n-butyl propionate, 2-heptanone / 2,6-dimethyl-4-heptanone and 2-heptanone / n-butyl acetate. Acetate or 2-heptanone / n-butyl propionate is preferred.

Such an organic solvent may be contained in the developer in an amount of 90 to 100 wt%, preferably more than 95 wt%, more than 98 wt%, more than 99 wt% or 100 wt%, based on the total weight of the developer.

The developer may include other additives, for example, a surfactant and the like. Such an additive may be contained in a small amount, for example, in an amount of about 0.01 to 5 wt% based on the total weight of the developer.

The developer may be applied to the photoresist composition layer by a known method, for example, spin coating or puddle coating. The development can be performed for a time sufficient to remove unexposed areas of the photoresist composition layer, and can be performed at room temperature for, for example, 5 seconds to 30 seconds.

The developed photoresist composition layer can be further cured by performing additional baking at a temperature of 100 캜 to 150 캜 for several minutes.

The developed substrate can be selectively treated with the substrate region from which the photoresist has been removed and can chemically etch or plate the substrate region with the photoresist stripped, for example, according to methods well known in the art. Plasma gas etching such as hydrofluoric acid etching solution and oxygen plasma etching may be used as the etching agent. For example, a layer of antireflective coating composition may be removed with a substrate etch using a plasma gas etch.

Hereinafter, the present invention will be described in more detail by way of examples. The following examples are illustrative of the present invention, but the present invention is not limited to the following examples.

Synthesis of polymers suitable for 193 nm antireflective coatings

The reaction equipment used in the following Production Examples and Examples was composed of a 100 mL three-necked flask, a round bottom flask equipped with a mechanical stirrer, a temperature control box, a temperature probe, a heated oil bath, and a condenser.

Production Example: Synthesis of Polymer A-1

To the reaction flask, 13.0 g of tris (2-hydroxyethyl) isocyanurate, 8.6 g of tris (2-carboxyethyl) isocyanurate, 0.24 g of monohydrate, 5.16 g of n-butanol, and 14.6 g of anisole were added in that order. The reaction flask was heated to 140 to 160 ° C and reacted for 6 hours with vigorous stirring. N-butanol with anisole was slowly distilled out of the reaction flask. The resulting reaction was diluted with 67.8 g methyl 2-hydroxyisobutyrate and neutralized with triethylamine.

To 19.2 g of the obtained polymer solution, 4.09 g of methyl-2-hydroxyisobutyrate and 9.92 g of tetramethoxymethyl glycoluril were added. It was reacted with stirring at 50 < 0 > C for 3 hours, cooled to ambient temperature and neutralized with triethylamine.

The resulting reaction was precipitated by the addition of 10-fold excess of isopropanol / heptane (60/40, v / v). The precipitate was washed with heptane and filtered through a Buchner funnel to obtain a solid polymer, followed by air drying and drying at 40-50 ° C overnight under vacuum to obtain a polymer.

The obtained polymer had a Mw of 8500 and a molecular weight distribution of 2.9 in GPC (THF).

Production Example: Synthesis of Polymer A-2

27.4 g of t-butylacetyl bis (2-carboxyethyl) isocyanurate, 14.3 g of tris (2-hydroxyethyl) isocyanurate, 8.3 g of 1,2-propanediol and 30 g of anisole Were added in any order. The reaction flask was heated to 150 < 0 > C and reacted with vigorous stirring for 6 hours. The reaction by-products and solvent were slowly distilled out of the flask. The resulting reaction product was diluted with tetrahydrofuran (THF) to a solid content of 30 wt%.

The resulting reaction was subjected to precipitation by adding 10-fold excess of isopropanol. The precipitate was collected and filtered in a Buchner funnel to obtain a solid polymer, followed by air drying and drying at 40-50 ° C under vacuum to obtain a polymer.

The polymer obtained had a Mw of 8700 in GPC (THF), a molecular weight distribution of 1.96, n193 of 1.94 and k193 of 0.24.

Preparation of anti-reflective coating composition

In the following Examples and Comparative Examples, the following materials were used.

(A-1) and (A-2) Polymers: Use of the polymers prepared above.

(B-1) Acid catalyst: p-toluenesulfonic acid (PTSA).

(C-1) Crosslinking agent: tetramethoxy glycoluril (TMGU).

(D-1) Solvent: methyl 2-hydroxyisobutyrate (HBM).

Comparative Example 1

(B-1), 0.732 g of the crosslinking agent (C-1) and 346.5 g of the solvent (D-1) were mixed and stirred for 1 hour. Thereafter, polytetrafluoroethylene ( PTFE).

Comparative Example 2

(B-1), 0.732 g of the crosslinking agent (C-1) and 346.5 g of the solvent (D-1) were mixed and stirred for 1 hour and then filtered with a 0.45 μm PTFE filter Respectively.

Example 1

(A-2), 0.0272 g of an acid catalyst (B-1), 0.509 g of a crosslinking agent (C-1) and 339.7 g of a solvent (D-1) 0.204 g of triphenylsulfonium triflate (TPS-Tf) was added thereto. This was stirred for 1 hour and then filtered through a 0.45 mu m PTFE filter.

193nm NTD lithography performance evaluation

The antireflective coating compositions prepared in the above Examples and Comparative Examples were used to test the lithographic performance at the time of negative tone development.

First, a silicon substrate was prepared, and an antireflection film (n193 = 1.69, k193 = 0.63) for reflectance adjustment was spin-coated thereon, and baked at 205 deg. C to cure the antireflection film. On the substrate having the antireflection film formed thereon, the antireflection coating composition prepared in the foregoing Examples and Comparative Examples was spin-coated to form a film. At this time, the thickness was adjusted so as to minimize the substrate reflectance with respect to the light of 193 nm during the exposure by controlling the spin speed. The resulting coating film was baked at 205 DEG C to cure the antireflective coating film. On the cured coating film, a photoresist emulsion for NTD was coated and exposed. The exposure equipment used was S610C (emulsion lithography, NA 1.3, X-dipole illumination, Sigma: 0.74-0.95, Y-polarized, 41nm / 82p 6% 180 ° PSM mask) from Nikon. And then developed with n-butyl acetate to obtain a line / space pattern.

The developed pattern was analyzed by an electron scanning microscope to observe the line width of the pattern, and the image of the pattern according to the light irradiation amount is shown in FIG. In addition, the minimum pattern line width (line CD) was measured and summarized in Table 1 below.

Antireflective coating composition Minimum pattern line width Comparative Example 1 45.47 nm Comparative Example 2 43.72 nm Example 1 37.33 nm

As shown in Table 1, when the coating film formed of the antireflective coating composition of Example 1 was formed, the minimum pattern line width of the pattern developed on the photoresist composition layer was much higher than that of Comparative Examples 1 and 2 . Thus, it can be seen that the antireflective coating film used in the lithography process of the NTD exerts excellent effects when the photoacid generator is added as in the composition of Example 1.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, It is to be understood that the invention may be practiced within the scope of the appended claims.

Claims (10)

(1) forming on the substrate a layer of an antireflective coating composition comprising (a) an organic polymer, (b) a photoacid generator, and (c) a crosslinking agent;
(2) forming a layer of a photoresist composition on the antireflective coating composition layer;
(3) exposing the photoresist composition layer and the antireflective coating composition layer simultaneously to active radiation and then baking; And
(4) developing the exposed photoresist composition layer with an organic solvent developer.
The method according to claim 1,
Wherein the photoacid generator is an onium salt-based photoacid generator.
3. The method of claim 2,
Wherein the onium salt is a sulfonate and a sulfonate salt having an aromatic group.
The method according to claim 1,
Characterized in that the antireflective coating composition comprises 0.01 to 15% by weight of the photoacid generator based on the weight of solids of the composition.
The method according to claim 1,
Characterized in that the antireflective coating composition further comprises a thermal acid generator. ≪ Desc / Clms Page number 13 >
6. The method of claim 5,
Wherein the thermal acid generator is a benzene sulfonic acid thermal acid generator.
The method according to claim 1,
Wherein the crosslinking agent is a glycoluril-based crosslinking agent.
The method according to claim 1,
Wherein the organic polymer comprises:
(a-1) at least one structural unit derived from a cyanurate compound having at least two functional groups selected from carboxy and carboxy ester; And
(a-2) a method for forming a pattern by a negative tone phenomenon, which comprises at least one structural unit derived from a diol or a polyol compound.
The method according to claim 1,
Wherein the photoresist composition comprises a matrix polymer, a photoacid generator, and a solvent,
Wherein the matrix polymer comprises at least one unit having an acid-cleavable protecting group. ≪ RTI ID = 0.0 > 11. < / RTI >
The method according to claim 1,
Forming a layer of a second antireflective coating composition different from said antireflective coating composition layer on said substrate prior to forming said antireflective coating composition layer,
Wherein the anti-reflective coating composition layer is formed on the second anti-reflective coating composition layer.

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