TW201512296A - Resist underlayer film forming composition containing trihydroxynaphthalene novolac resin - Google Patents

Abstract

To provide a resist underlayer film forming composition which has heat resistance and resistance to pattern bending, and which is used in a lithography process for the production of a semiconductor device. A resist underlayer film forming composition for lithography, which contains a polymer that has a unit structure represented by formula (1). (In formula (1), A represents a hydroxy group-substituted naphthylene group that is derived from trihydroxynaphthalene and has three hydroxy groups; and B represents a monovalent fused aromatic hydrocarbon ring group wherein from two to four benzene rings are fused).

Description

Anti-corrosion underlayer film forming composition containing trihydroxynaphthalene novolak resin

The present invention relates to a resist pattern forming composition for lithography which is effective for processing a semiconductor substrate, a resist pattern forming method for forming a composition using the resist underlayer film, and a method for manufacturing a semiconductor device.

In the past, in the manufacture of semiconductor devices, microfabrication by photolithography using photolithography has progressed. The microfabrication is a film in which a photoresist composition is formed on a substrate to be processed such as a tantalum wafer, and an active light such as ultraviolet rays is irradiated on the upper surface of the mask pattern of the semiconductor device pattern, and the light is obtained after development. The resist pattern is a processing method in which a substrate to be processed such as a tantalum wafer is etched as a protective film. However, in recent years, due to the development of high integration of semiconductor devices, the active light used has a tendency to be short-wavelength from KrF excimer laser (248 nm) to ArF excimer laser (193 nm). The influence of random reflection or standing waves from the active light substrate becomes a big problem. Therefore, a method of providing a reflection preventing film (Bottom Anti-Reflective Coating, BARC) between the photoresist and the substrate to be processed is widely used. Review.

In the future, when the resist pattern is refined, a problem of resolution or a problem that the resist pattern may fall after development may occur, so that it is expected to be thinned. Therefore, it is difficult to obtain a resist pattern film thickness which is processed into a sufficient surface of the substrate, and the resist underlayer film formed between the resist and the processed semiconductor substrate is not only a resist pattern but also has a mask as a substrate during processing. The functional process is necessary. As the underlayer film for the above-mentioned process, it is required to have a resist having a high etching rate (faster etching speed) than the resist underlayer film, and it is required to have a resist ratio close to the dry etching rate of the resist. The underlayer film, the resist underlayer film for lithography having a selection ratio of a dry etching rate smaller than that of the resist, or the resist underlayer film for lithography having a selection ratio of a dry etching rate smaller than that of the semiconductor substrate.

As a polymer used for the composition for forming a resist underlayer film, a novolac resin of dihydroxynaphthalene and benzaldehyde or naphthaldehyde has been disclosed (see Patent Document 1).

A polyhydroxy novolac resin has been disclosed as a polymer used for forming a composition of the above-mentioned resist underlayer film (see Patent Document 2).

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Special Opening 2009-229666

[Patent Document 2] International Patent Application WO2012/176767

An object of the present invention is to provide a resist underlayer film forming composition for use in photolithography processing for manufacturing a semiconductor device. Further, an object of the present invention is to provide a resist underlayer film for lithography which has an excellent resist pattern and a selection ratio close to the dry etching rate of the resist, which does not cause intermixing with the resist layer, and has a specific resistance. The etch rate of the etch is smaller than the etch underlayer film or the etch underlayer film having a smaller dry etch rate than the semiconductor substrate. Further, the present invention provides the following performance to the under-layer resist film which is capable of effectively absorbing the reflected light from the substrate when the irradiation light having a wavelength of 248 nm, 193 nm, or 157 nm is used for the microfabrication. Further, the present invention provides a method for forming a resist pattern using the underlayer film forming composition of the present invention. Further, the present invention further provides a resist underlayer film forming composition capable of forming a resist underlayer film having heat resistance.

According to a first aspect of the present invention, a resist underlayer film forming composition for lithography, which comprises a polymer having a unit structure represented by formula (1);

(In the formula (1), A is a three-hydroxyl group having a hydroxy-substituted naphthylene group derived from a trihydroxynaphthalene, and B is a divalent condensed aromatic hydrocarbon ring group in which two to four benzene rings are condensed).

In the second aspect, the condensed aromatic hydrocarbon ring group of B is a naphthalene ring group, an anthracene ring group, or an anti-underlayer film forming composition described in the first aspect of the anthracene ring group.

As a third aspect, the condensed aromatic hydrocarbon ring group of B is a first viewpoint having a halogen group, a hydroxyl group, a nitro group, an amine group, a carboxyl group, a carboxylate group, a nitrile group, or a combination thereof as a substituent. The under-resist film formed in the second aspect is a composition.

The anti-corrosion underlayer film forming composition according to any one of the first aspect to the third aspect of the present invention.

The anti-corrosion underlayer film forming composition according to any one of the first aspect to the fourth aspect of the present invention, further comprising the acid and/or the acid generator.

According to a sixth aspect, a resist underlayer film obtained by applying the underlayer film forming composition according to any one of the first aspect to the fifth aspect to a semiconductor substrate is fired.

According to a seventh aspect, a method for forming a resist pattern for use in the production of a semiconductor including the formation of a resist underlayer film according to any one of the first aspect to the fifth aspect. The composition is applied to a semiconductor substrate and fired to form a resist underlayer film.

According to a eighth aspect of the invention, there is provided a method for producing a semiconductor device, comprising: forming a resist underlayer film on a semiconductor substrate by using a resist underlayer film forming composition according to any one of the first aspect to the fifth aspect; It a step of forming a resist film thereon, a step of forming a resist pattern by irradiation and development of light or electron lines, and etching the underlayer film by a resist pattern formed And a step of processing the semiconductor substrate by patterning the underlayer film.

According to a ninth aspect, a method for producing a semiconductor device comprising the step of forming a resist underlayer film of the resist underlayer film forming composition according to any one of the first aspect to the fifth aspect; a step of forming a hard mask thereon, a step of further forming a resist film thereon, a step of forming a resist pattern by irradiation and development of light or electron lines, and a resist formed by the resist The pattern etches the hard mask, the step of etching the underlayer film by the patterned hard mask, and processing the semiconductor substrate by patterning the underlayer film step.

According to a tenth aspect, the hard mask is a production method described in the ninth aspect, which is formed by coating an inorganic material or vapor deposition of an inorganic material.

Since the composition is formed by the underlayer film of the present invention, since the upper layer portion of the formed underlayer film and the layer to be coated are not mixed with each other, a pattern shape of a good resist can be formed.

Moreover, the resist underlayer film forming composition of the present invention can provide an effect of suppressing reflection from the substrate efficiently on the underlying resist film. Therefore, the formed underlayer film can have an effect as an exposure and antireflection film.

Further forming a composition by the underlayer film of the present invention An excellent underlayer film having a selection ratio of dry etching rate close to the resist, a selection ratio of a dry etching speed smaller than that of the resist, or a selection ratio smaller than a dry etching speed of the semiconductor substrate .

To prevent corrosion caused by the refinement of the resist pattern The pattern was poured after development and subjected to resist thin film formation. In such a thin film resist, the resist pattern is transferred to the underlayer film by an etching process, the underlayer film is processed as a mask for substrate processing, or the resist pattern is transferred to the underlayer film by an etching process. Further, the pattern transferred to the underlayer film is composed of a different gas, and the process of transferring to the underlayer film is repeated, and finally the substrate processing is performed. The underlayer film of the present invention and the composition for forming the same can be effectively used in the process, and when the substrate is processed by using the underlayer film of the present invention, it is for processing a substrate (for example, a thermal ruthenium film on a substrate, nitrogen). The ruthenium film, polysilicon film, etc.) have sufficient etching resistance.

On the other hand, the underlayer film of the present invention can be used as a film having a planarization film, a resist underlayer film, a resist layer of a resist layer, and a dry etching selectivity. Thereby, the pattern formation of the resist pattern in the photolithography process of semiconductor fabrication can be performed easily and accurately.

A resist underlayer film having a composition for forming a resist underlayer film of the present invention is formed on a substrate, a hard mask is formed thereon, a resist film is formed thereon, and a resist pattern is formed by exposure and development. Transferring the resist pattern to the hard mask by dry etching, transferring the resist pattern transferred to the hard mask to the underlying resist film by dry etching, and performing the semiconductor substrate on the resist underlayer film Processing process. In the process, when dry etching is performed by a dry etching gas, the pattern formed by the resist underlayer film of the present invention can be patterned and resistant to bending. Excellent pattern of anti-wiggling.

Further, in the process, when the hard mask is applied by a coating type composition containing an organic polymer or an inorganic polymer (cerium polymer) and a solvent, it can be carried out by vacuum evaporation of an inorganic material. In the case of an inorganic substance (for example, cerium nitride oxide), the vapor deposition material is deposited on the surface of the underlayer film, but at this time, the temperature of the surface of the underlayer film is raised to about 400 °C. Since the polymer used in the present invention is often a polymer having a benzene-based unit structure, it has extremely high heat resistance and does not cause thermal deterioration due to deposition of a vapor deposition material.

[Formation of the Invention]

The present invention is a resist underlayer film forming composition for lithography containing a polymer having a unit structure represented by the formula (1).

The above polymer is used as a novolak resin in which trihydroxynaphthalene is condensed with an aldehyde.

In the present invention, the resist underlayer film forming composition for lithography contains the polymer and a solvent. When a crosslinking agent and an acid are contained, an additive such as an acid generator or a surfactant may be contained as necessary. The solid content of the composition is from 0.1 to 70% by mass, or from 0.1 to 60% by mass. The solid content is a ratio of the total component of the solvent to be removed from the underlayer film forming composition. The solid content may be contained in a solid content of from 1 to 100% by mass, or from 1 to 99.9% by mass, or from 50 to 99.9% by mass, or from 50 to 95% by mass, or from 50 to 90% by mass.

The polymer used in the present invention has a weight average molecular weight of 600 to 1,000,000, or 600 to 200,000, 600 to 100,000, or 600 to 10000, or 1000 to 5000, or 1500 to 3000.

In the formula (1), A is a hydroxy-substituted naphthylene group derived from trihydroxynaphthalene, and B is a monovalent condensed aromatic hydrocarbon ring group in which 2 to 4 benzene rings are condensed.

Further, the condensed aromatic hydrocarbon ring group of B may be a naphthalene ring group, an anthracene ring group, or an anthracene ring group. It is preferred to use a naphthalene ring group and an anthracene ring group. It is also more preferable to use an anthracene ring group. Examples of the carboxylate group of the substituent of the condensed aromatic hydrocarbon ring group of B include ethyl acetate, n-butyl acetate, i-butyl acetate, and methyl propionate. Further, examples of the halogen group as a substituent include a fluorine group, a chlorine group, a bromine group, and an iodine group.

The following unit structure can be exemplified as the unit structure represented by the above formula (1).

In the present invention, a novolac resin having a repeating unit structure represented by the formula (1) wherein a trihydroxynaphthalene is condensed with an aldehyde can be used as a polymer.

The aldehyde is an aldehyde having a condensed aromatic hydrocarbon ring group such as naphthalene, anthracene or an anthracene, and examples thereof include naphthaldehyde, anthracene carboxylaldehyde, and hydrazinecarboxyaldehyde.

In the reaction, for the above phenolic 1 molar, aldehydes It is from 0.1 to 10 moles, preferably from 0.8 to 2.2 moles, more preferably at a ratio of 1.0 moles.

As the acid catalyst used in the above condensation reaction, for example, As the inorganic acid such as sulfuric acid, phosphoric acid or perchloric acid, an organic sulfonic acid such as p-toluenesulfonic acid or p-toluenesulfonic acid monohydrate, a carboxylic acid such as formic acid or oxalic acid. The amount of acid catalyst used can be selected depending on the type of acid used. The amount to be used is generally 0.001 to 10,000 parts by mass, preferably 0.01 to 1000 parts by mass, more preferably 0.1 to 100 parts by mass, per 100 parts by mass of the total of the phenols and aldehydes.

The above condensation reaction can also be carried out without a solvent, but it is usually carried out using a solvent. It can be used as a solvent without hindering the reaction. For example, a cyclic ether such as tetrahydrofuran or dioxane can be mentioned. Further, when the acid catalyst to be used is, for example, a liquid such as formic acid, it can function as a solvent.

The reaction temperature at the time of condensation is generally from 40 ° C to 200 ° C. The reaction time is variously selected depending on the reaction temperature, but it is usually from 30 minutes to 50 hours.

The weight average molecular weight Mw of the polymer obtained as above is generally from 600 to 1,000,000, or from 600 to 200,000 to 600 to 100,000, or from 600 to 10,000, or from 1,000 to 5,000, or from 1,500 to 3,000.

The above polymer may be used by mixing other polymers in an amount of 30% by mass or less in the whole polymer.

Examples of such a polymer include a polyacrylate compound, a polymethacrylate compound, a polyacrylamide compound, and a poly A methacrylamide compound, a polyvinyl compound, a polystyrene compound, a polymaleimide compound, a polymaleic anhydride, and a polyacrylonitrile compound.

As a raw material monomer of a polyacrylate compound, it can be mentioned Methacrylate, ethyl acrylate, isopropyl acrylate, phenyl methacrylate, naphthalene acrylate, mercapto acrylate, mercapto methacrylate, phenyl acrylate, 2-hydroxyethyl acrylate , 2-hydroxypropyl acrylate, 2,2,2-trifluoroethyl acrylate, 4-hydroxybutyl acrylate, isobutyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, isobornyl Acrylate, 2-methoxyethyl acrylate, methoxy triethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, 3-methoxybutyl acrylate , 2-methyl-2-adamantyl acrylate, 2-ethyl-2-adamantyl acrylate, 2-propyl-2-adamantyl acrylate, 2-methoxybutyl-2- Adamantyl acrylate, 8-methyl-8-tricyclodecyl acrylate, 8-ethyl-8-tricyclodecyl acrylate, and 5-propenyloxy-6-hydroxynorbornene-2 - Carboxylic acid-6-lactone or the like.

As a raw material monomer of the polymethacrylate compound, Ethyl methacrylate, n-propyl methacrylate, n-pentyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, naphthalene methacrylate, mercaptomethyl Acrylate, mercaptomethyl methacrylate, phenyl methacrylate, 2-phenylethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2,2,2-Trifluoroethyl methacrylate, 2,2,2-trichloroethyl methacrylate, methacrylate, isobutyl methacrylate, 2-ethylhexyl Methyl methacrylate, isodecyl methacrylate, n-lauryl methacrylate, n-stearyl methacrylate, methoxy diethylene glycol methacrylate, methoxy polyethylene glycol Methacrylate, tetrahydrofurfuryl methacrylate, isobornyl methacrylate, tert-butyl methacrylate, isostearyl methacrylate, n-butoxyethyl methacrylate, 3 -Chloro-2-hydroxypropyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2-ethyl-2-adamantyl methacrylate, 2-propyl-2- Adamantyl methacrylate, 2-methoxybutyl-2-adamantyl methacrylate, 8-methyl-8-tricyclodecyl methacrylate, 8-ethyl-8-three Cyclodecyl methacrylate, 5-methylpropenyloxy-6-hydroxynorbornene-2-carboxylic acid-6-lactone, and 2,2,3,3,4,4,4-pentafluoro Butyl methacrylate and the like.

As a raw material monomer of the polyacrylamide compound, Examples of the propylene fluorenyl group, the N-methyl propylene fluorenyl group, the N-ethyl propylene fluorenyl group, the N-benzyl methacryl fluorenyl group, the N-phenyl propylene fluorenyl group, and the N,N-dimethyl propylene fluorenyl group Wait.

Examples of the raw material monomer of the polymethyl methacrylate oxime compound include methacryl fluorenyl group, N-methyl methacryl fluorenyl group, N-ethyl methacryl fluorenyl group, and N-benzyl methacryl propylene group. An anthracenyl group, an N-phenylmethacrylinyl group, and an N,N-dimethylmethacrylinyl group.

Examples of the raw material monomer of the polyethylene compound include vinyl ether, methyl vinyl ether, benzyl vinyl ether, 2-hydroxyethyl vinyl ether, phenyl vinyl ether, and propyl vinyl ether. Wait.

As a raw material monomer of a polystyrene compound, styrene, A Styrene, chlorostyrene, bromostyrene, and hydroxystyrene.

Examples of the raw material monomers of the polymaleimide compound include maleic imine, N-methyl maleimide, N-phenyl maleimide, and N-cyclohexylmalaya. Amines, etc.

These polymers are produced by dissolution of organic solvents Addition of a polymerizable monomer and, if necessary, a chain extender (for a monomer mass of 10% or less), a polymerization initiator is added to carry out a polymerization reaction, and then a polymerization stopper is added to produce a polymerization initiator. The amount of the polymerization initiator to be added is 1 to 10% by mass of the monomer, and the amount of addition as a polymerization stopper is 0.01 to 0.2% by mass based on the mass of the monomer. Examples of the organic solvent to be used include propylene glycol monomethyl ether, propylene glycol monopropyl ether, ethyl lactate, cyclohexanone, methyl ethyl ketone, and dimethylformamide. Examples of the chain shifting agent include a chain shifting agent. Examples of the polymerization initiators such as dodecyl mercaptan and dodecyl mercaptan include azobisisobutyronitrile and azobiscyclohexanecarbonitrile, and examples of the polymerization stopper include 4-methyl group. Oxyphenol and the like. The reaction temperature is 30 to 100 ° C, and the reaction time is selected from 1 to 48 hours.

The under-layer film forming composition of the present invention may contain cross-linking Ingredients. Examples of the crosslinking agent include melamine-based, substituted urea-based, and the like. It is preferably a crosslinking agent having at least two crosslinking groups to form a substituent, and examples thereof include methoxymethylated ethylene glycol urea, butoxymethylated ethylene glycol urea, and methoxymethylated melamine. Butoxymethylated melamine, methoxymethylated benzene melamine, butoxymethylated benzene melamine, methoxymethylated urea, butoxymethylated urea, methoxymethylation A compound such as thiourea or methoxymethylated thiourea. Also, A condensate of these compounds is used.

Further, as the crosslinking agent, a crosslinking agent having high heat resistance can be used. As a crosslinking agent having high heat resistance, a compound having an aromatic ring (for example, a benzene ring or a naphthalene ring) in the molecule to form a substituent can be preferably used.

As these compounds, the following formula (2) is mentioned A compound having a partial structure or a polymer or oligomer having a repeating unit represented by the following formula (3).

In the formula (2), R ₁₀ and R ₁₁ each represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms, n 10 represents an integer of 1 to 4, and n 11 is 1 to (5- An integer of n10), (n10+n11) is an integer of 2 to 5.

In the formula (3), R ₁₂ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, R ₁₃ represents an alkyl group having 1 to 10 carbon atoms, n12 represents an integer of 1 to 4, and n13 represents 0 to (4-n12). (n12+n13) represents an integer of 1 to 4. The oligomers and polymers may use a repeating unit number of from 2 to 100, or from 2 to 50.

Examples of the alkyl group having 1 to 10 carbon atoms in the above R ₁₀ to R ₁₃ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a cyclopropyl group, an n-butyl group, and an i-butyl group. Base, s-butyl, t-butyl, cyclobutyl, 1-methyl-cyclopropyl, 2-methyl-cyclopropyl, n-pentyl, 1-methyl-n-butyl, 2 -methyl-n-butyl, 3-methyl-n-butyl, 1,1-dimethyl-n-propyl, 1,2-dimethyl-n-propyl, 2,2-di Methyl-n-propyl, 1-ethyl-n-propyl, cyclopentyl, 1-methyl-cyclobutyl, 2-methyl-cyclobutyl, 3-methyl-cyclobutyl, 1 ,2-dimethyl-cyclopropyl, 2,3-dimethyl-cyclopropyl, 1-ethyl-cyclopropyl, 2-ethyl-cyclopropyl, n-hexyl, 1-methyl- N-pentyl, 2-methyl-n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1, 2-Dimethyl-n-butyl, 1,3-dimethyl-n-butyl, 2,2-dimethyl-n-butyl, 2,3-dimethyl-n-butyl, 3,3-Dimethyl-n-butyl, 1-ethyl-n-butyl, 2-ethyl-n-butyl, 1,1,2-trimethyl-n-propyl, 1, 2,2-Trimethyl-n-propyl, 1-ethyl-1-methyl-n-propyl, 1-ethyl-2-methyl-n-propyl, cyclohexyl, 1-methyl -cyclopentyl, 2-methyl-cyclopentyl, 3-methyl-cyclopentyl, 1-ethyl-cyclobutyl, 2-ethyl-cyclobutyl, 3-ethyl-cyclobutyl, 1,2-dimethyl-cyclobutyl, 1, 3-dimethyl-cyclobutyl, 2,2-dimethyl-cyclobutyl, 2,3-dimethyl-cyclobutyl, 2,4-dimethyl-cyclobutyl, 3,3- Dimethyl-cyclobutyl, 1-n-propyl-cyclopropyl, 2-n-propyl-cyclopropyl, 1-i-propyl-cyclopropyl, 2-i-propyl-cyclopropane 1,1,2-trimethyl-cyclopropyl, 1,2,3-trimethyl-cyclopropyl, 2,2,3-trimethyl-cyclopropyl, 1-ethyl-2 -methyl-cyclopropyl, 2-ethyl-1-methyl-cyclopropyl, 2-ethyl-2-methyl-cyclopropyl and 2-ethyl-3-methyl-cyclopropyl .

Examples of the aryl group having 6 to 20 carbon atoms in the above R ₁₀ and R ₁₁ include a phenyl group, an o-methylphenyl group, an m-methylphenyl group, a p-methylphenyl group, and an o-chlorobenzene. Base, m-chlorophenyl, p-chlorophenyl, o-fluorophenyl, p-fluorophenyl, o-methoxyphenyl, p-methoxyphenyl, p-nitrophenyl, p - cyanophenyl, α-naphthyl, β-naphthyl, o-biphenyl, m-biphenyl, p-biphenyl, 1-indenyl, 2-indenyl, 9-fluorenyl, 1- Fenyl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl and 9-phenanthryl.

The compound represented by the formula (2), the polymer represented by the formula (3) or the oligomer are exemplified below.

The above compounds can be used in the Asahi Organic Materials Industry Co., Ltd., Honshu Products of the chemical industry (shares). For example, among the above crosslinking agents, the compound of the formula (2-21) can be obtained from the trade name TM-BIP-A of Asahi Organic Materials Co., Ltd.

The amount of the crosslinking agent to be added varies depending on the coating solvent to be used, the underlying substrate to be used, the desired solution viscosity, the desired film shape, and the like, but it is preferably 0.001 to 80% by mass based on the total solid content. It is preferably from 0.01 to 50% by mass, more preferably from 0.05 to 40% by mass. These crosslinking agents can cause a crosslinking reaction by self-condensation, but when the above-mentioned polymer of the present invention has a crosslinkable substituent, it can be crosslinked with these crosslinkable substituents. reaction.

In the present invention, as a catalyst for promoting the above crosslinking reaction, Adding acidic compounds 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 A thermal acid generator such as 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyltosylate, or other alkyl sulfonate. The compounding amount is 0.0001 to 20% by mass, preferably 0.0005 to 10% by mass, and more preferably 0.01 to 3% by mass, based on the total solid content.

The coating type underlayer film for lithography of the present invention forms a composition, In the photolithography step, a photoacid generator may be added in accordance with the acidity of the photoresist coated on the upper layer. Examples of preferred photoacid generators include bismuth (4-t-butylphenyl) iodonium trifluoromethanesulfonate and triphenylsulfonium trifluoromethanesulfonate. Halogen-containing compound-based photoacid generators such as benzo-bis(trichloromethyl)-s-triazine, benzoin tosylate, N-hydroxysuccinimide trifluoromethanesulfonate, etc. A sulfonic acid photoacid generator or the like. The photoacid generator is from 0.2 to 10% by mass, preferably from 0.4 to 5% by mass, based on the total solid content.

The resist underlayer film forming composition for lithography of the present invention is In addition to the above, a light absorbing agent, a rheology modifier, a subsidizing agent, a surfactant, and the like may be further added as necessary.

Examples of the light-absorbing agent to be further added include, for example, "Technology and Market for Industrial Pigments" (CMC Publishing) or "Dye Notes" (edited by the Society of Organic Synthetic Chemistry), commercially available light absorbing agents such as C.I. DisperseYellow1,3,4,5,7,8,13,23,31,49,50,51,54,60,64,66,68,79,82,88,90,93,102,114 and 124; CIDisperseOrange1,5 , 13, 25, 29, 30, 31, 44, 57, 72 and 73; CI Disperse Red 1,5,7,13,17,19,43,50,54,58,65,72,73,88,117,137,143,199 and 210; CIDisperseViolet 43; CI Disperse Blue 96; CIFluorescent Brightening Agents 112, 135 and 163; CI Solvent Orange 2 and 45; CI Solvent Red 1, 3, 8, 23, 24, 25, 27 and 49; CIPigment Green 10; CIPigment Brown 2 and the like. The light absorbing agent is generally added in an amount of 10% by mass or less, preferably 5% by mass or less, based on the total solid content of the composition for forming a resist underlayer for lithography.

The purpose of the rheology modifier is to mainly improve the corrosion resistance. The fluidity of the film forming composition, particularly in the baking step, improves the film thickness uniformity of the underlayer film or the filling property of the underlying film forming composition inside the hole. Specific examples thereof include dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, and butyl iso Phthalic acid derivatives such as mercaptophthalate, di-n-butyl adipate, diisobutyl adipate, diisooctyl adipate, octyldecyl adipate, etc. Acid derivatives, di-n-butyl malate, diethyl malate, dimercapto malate, maleic acid derivatives, methyl oleate, butyl oleate, tetrahydrofurfuryl oleic acid An oleic acid derivative such as an ester or a stearic acid derivative such as n-butyl stearate or glyceryl stearate. These rheology modifiers generally have a ratio of less than 30% by mass to the total solid content of the composition for forming a resist underlayer for lithography.

Then the subsidy is mainly to improve the substrate or resist and resist The adhesion of the underlayer film forming composition is particularly added for the purpose of developing the image without peeling off the resist. Specific examples include chlorodecanes such as trimethylchlorodecane, dimethylvinylchlorodecane, methyldiphenylchlorodecane, and chloromethyldimethylchlorosilane, and trimethylmethoxydecane. Alkoxydecanes such as dimethyldiethoxydecane, methyldimethoxydecane, dimethylvinylethoxysilane, diphenyldimethoxydecane, and phenyltriethoxydecane, Hexamethyldioxane, N,N'-bis(trimethylsulfonyl)urea, dimethyltrimethyldecylamine, trimethyldecyl imidazole, etc., decazane, vinyl trichlorodecane , γ-chloropropyltrimethoxydecane, γ-aminopropyltriethoxydecane, γ-glycidoxypropyltrimethoxydecane and other decanes, benzotriazole, benzimidazole, hydrazine a heterocyclic compound such as azole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, uridine, thiouracil, mercapto imidazole, mercaptopyrimidine or 1,1-dimethyl Urea such as urea or 1,3-dimethylurea, or a thiourea compound. These adhesion aids are generally added to the total solid content of the composition for forming a resist underlayer for lithography, which is generally less than 5% by mass, preferably less than 2% by mass.

The resist underlayer film forming composition for lithography of the present invention is A surfactant may be added when pinholes, streaks, or the like are not generated, and when the coating property is not further improved on the surface. Examples of the surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene hexadecyl ether, and polyoxyethylene oleyl ether, and polyoxyethylene octane. Polyoxyethylene alkyl allyl ethers such as phenol ethers, polyoxyethylene nonyl phenol ethers, polyoxyethylene. Polyoxypropylene block copolymers, sorbitol monolaurate, sorbitol monopalmitate, sorbitol monostearate, sorbus Sorbitol fatty acid esters such as sugar alcohol monooleate, sorbitol trioleate, sorbitol tristearate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitol single palm Nonionics such as polyoxyethylene sorbitol fatty acid esters such as acid esters, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitol trioleate, and polyoxyethylene sorbitan tristearate Interfacial surfactant, EftopEF301, EF303, EF352 (trade name of Tochem Products), Megafac F171, F173, R-30 (trade name of Dainippon Ink (share)), FLUORADFC430, FC431 (Sumitomo 3M) a product name), a fluorine-based surfactant such as Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (trade name of Asahi Glass Co., Ltd.), and an organic siloxane polymer KP341 ( Shin-Etsu Chemical Industry Co., Ltd.). The blending amount of the surfactant is generally 2.0% by mass or less, preferably 1.0% by mass or less, based on the total solid content of the resist underlayer film forming composition for lithography of the present invention. These surfactants may be added singly or in combination of two or more kinds.

In the present invention, as the above polymer and a crosslinking agent are dissolved For solvent such as fractional or cross-linking catalyst, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol alone may be used. Methyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, propylene glycol propyl ether Acid ester, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, Ethyl hydroxyacetate, 2-hydroxyl Methyl 3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate , methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate and the like. These organic solvents may be used singly or in combination of two or more.

Further, a high boiling point solvent such as propylene glycol monobutyl ether or propylene glycol monobutyl ether acetate may be mixed and used. Among these solvents, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, and cyclohexanone are preferred because they can improve the leveling property.

The resist used in the present invention is a photoresist or an electron line resist.

As the photoresist applied to the upper portion of the resist underlayer film for lithography of the present invention, either a negative type or a positive type can be used, and examples thereof include a novolac resin and a 1,2-naphthoquinonediazide. A positive-type photoresist formed by a sulfonate, a chemically amplified photoresist formed by a binder having a base capable of increasing alkali dissolution rate by acid decomposition, and a photo-acid generator, which can be improved by an alkali-soluble binder A chemically amplified photoresist formed by a low molecular compound and a photoacid generator having an alkali dissolution rate of a photodegradation of an acid, and an adhesive having a base capable of increasing the dissolution rate of an alkali by acid decomposition A chemically amplified photoresist formed by a low molecular weight compound and a photoacid generator having a photodegradation rate by acid decomposition, a photoresist having Si atoms in a skeleton, and the like, and the product name APEX manufactured by Rohm & Haas Co., Ltd. is mentioned, for example. -E.

In addition, as the electron beam resist applied to the upper portion of the resist underlayer film for lithography of the present invention, for example, a resin containing an aromatic ring at the terminal and an electron beam by Si-Si bonds in the main chain are mentioned. Irradiating the composition of the acid generator which produces acid, or having a hydroxyl group containing an N-carboxyamine A composition of a poly(p-hydroxystyrene) substituted by a machine base and an acid generator which generates an acid by electron beam irradiation. In the latter electronic wire resist composition, an acid generated by an acid generator is reacted with an N-carboxyamino group of a polymer side chain by electron beam irradiation, and a side chain of the polymer is decomposed into a hydroxyl group to be dissolved in an alkali-soluble one. Alkaline developing solution, forming a resist pattern. The acid generator which generates an acid by electron beam irradiation may, for example, be a 1,1-bis[p-chlorophenyl]-2,2,2-trichloroethane or a 1,1-bis[p-methoxy group. Phenyl]-2,2,2-trichloroethane, 1,1-bis[p-chlorophenyl]-2,2-dichloroethane, 2-chloro-6-(trichloromethyl)pyridine A sulfonate such as a halogenated organic compound, a triphenylsulfonium salt or a diphenyliodonium salt such as a sulfonium salt, a nitrobenzyltosylate or a dinitrobenzyltosylate.

Has a resist underlayer film forming group for lithography using the present invention As the anti-corrosion liquid for the anti-corrosion underlayer film formed by the product, an inorganic base such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium citrate, metafluoric acid or ammonia water, ethylamine or n-propyl can be used. a first amine such as a base amine, a second amine such as diethylamine or di-n-butylamine, a third amine such as triethylamine or methyldiethylamine, dimethylethanolamine or triethanolamine An alcoholic amine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, a fourth-order ammonium salt such as choline, a cyclic amine such as pyrrole or piperidine, or an alkali-based aqueous solution. Further, an appropriate amount of an alcohol such as isopropyl alcohol or a surfactant such as a nonionic surfactant may be added to the aqueous alkali solution. The preferred imaging liquids among them are a fourth-order ammonium salt, more preferably tetramethylammonium hydroxide and choline.

Next, the method for forming a resist pattern of the present invention will be described. Substrate for the fabrication of precision integrated circuit components (eg germanium/cerium oxide) A resist underlayer film is formed on a transparent substrate such as a coating, a glass substrate or an ITO substrate by a suitable coating method such as a spinner or an applicator, and then baked and cured to form a coating-type underlayer film. Among them, the film thickness of the underlayer film is preferably 0.01 to 3.0 μm. Further, as a post-coating barbecue condition, it is from 80 to 350 ° C for 0.5 to 120 minutes. Thereafter, directly on the underlayer film, or if necessary, one to several layers of the coating material are formed on the underlayer film, and then the resist is applied, and the light or electron beam is irradiated through the predetermined mask. A good resist pattern can be obtained after development, cleaning and drying. It can also be heated by light or electron beam irradiation (PEB: PostExposureBake) as necessary. On the other hand, the resist is removed by dry etching by the developing step to remove the portion of the underlayer film, and the desired pattern can be formed on the substrate.

The exposure light source in the above photoresist is a chemical line such as near ultraviolet light, far ultraviolet light, or extreme ultraviolet light (for example, EUV, wavelength 13.5 nm), for example, 248 nm (KrF laser light), 193 nm (ArF laser light), 157 nm (F ₂ ). Laser light). In the light irradiation, the method of generating an acid from the photoacid generator is not particularly limited, and the exposure amount is 1 to 2000 mJ/cm ² , or 10 to 1500 mJ/cm ² , or 50 to 1000 mJ/cm ² .

Further, the electron beam irradiation of the electron beam resist can be irradiated by, for example, an electron beam irradiation device.

In the present invention, the semiconductor package can be manufactured through the following steps This step is a step of forming a resist underlayer film formed on the semiconductor substrate by the resist underlayer film of the present invention, a step of forming a resist film thereon, and irradiating and developing by light or electron beam. Step of forming a resist pattern The step of etching the resist underlayer film formed by the resist pattern and the step of processing the semiconductor substrate by the patterned resist underlayer film.

In the future, if the refinement of the resist pattern continues, there is a problem of resolution or a problem that the resist pattern falls after development, and thus it is expected that the resist is thinned. Therefore, it is difficult to obtain a resist pattern film thickness sufficient for substrate processing, and not only a resist pattern but also a resist underlayer film formed between the resist and the processed semiconductor substrate may have a photomask as a substrate processing. The functional process becomes necessary. As a resist underlayer film for such a process, unlike the past high etching rate underlayer film, a resist underlayer film for lithography having a selection ratio of dry etching speed close to the resist is required, and the resist is provided. The comparison of the dry etching speed is smaller than that of the resist underlayer film for lithography or the resist underlayer film for lithography having a smaller dry etching speed than the semiconductor substrate. The underlayer film of the composition for forming a resist underlayer film of the present invention satisfies such requirements, and the film of the underlayer film can impart reflection preventing energy, and the function of the past antireflection film can be incorporated.

On the other hand, in order to obtain a fine resist pattern, when the underlayer film is dry-etched, the resist pattern and the underlayer film can be used in a process which is thinner than the pattern width at the time of resist development. . As the underlayer film for such a process, a resist underlayer film having a selection ratio of a dry etching rate close to that of the resist is required to be different from the conventional high etching rate antireflection film. The underlayer film obtained by forming the composition of the underlayer film of the present invention satisfies such requirements, and the film of the underlayer film can provide reflection preventing energy, and can function as a reflection preventing film in the past.

In the present invention, the underlayer film of the present invention is formed on the substrate Thereafter, the resist film may be applied directly to the underlayer film or, if necessary, a film of a layer to a plurality of layers may be formed on the underlayer film. Thereby, the pattern width of the resist is narrowed, and even when the thin resist is covered while preventing the pattern from being poured, the processing of the substrate can be performed by selecting an appropriate etching gas.

That is, the semiconductor device can be manufactured by the following steps. a step of forming a resist underlayer film on a semiconductor substrate by forming a composition of a resist underlayer film, forming a hard mask (for example, nitrogen) by a hard mask or evaporation using a coating material containing a bismuth component or the like thereon a step of forming a resist film thereon, a step of forming a resist film thereon, a step of forming a resist pattern by irradiation of light or electron lines, and a hard mask by forming a resist pattern a step of etching with a halogen-based gas, a step of etching the underlayer film by an oxygen-based gas or a hydrogen-based gas by a patterned hard mask, and a patterned underlayer film by patterning The step of processing the semiconductor substrate with a halogen-based gas.

The composition for forming a resist underlayer film for lithography of the present invention When the effect of the antireflection film is taken into consideration, since the light absorbing portion is in the form of a skeleton, there is no diffusing material in the photoresist during heating and drying, and the light absorbing portion has a sufficiently large light absorbing property, so that it has high reflection light prevention. effect.

Further, the resist underlayer film forming composition for lithography of the present invention has high heat stability, can prevent contamination of the upper layer film due to decomposition products during firing, and can have a wide temperature range of the firing step. .

Moreover, the resist underlayer film forming composition for lithography of the present invention can be used as a function of preventing light reflection by a process condition, and further A film that prevents interaction between a substrate and a photoresist, or a function that prevents a bad influence on a substrate generated by exposure of a material or photoresist used for photoresist.

[Examples] (Preparation of raw materials) Synthesis of trihydroxynaphthalene

In a 500-ml eggplant-shaped flask, 15.0 g (86.1 mmol) of 5-hydroxy-1,4-naphthoquinone (manufactured by Tokyo Chemical Industry Co., Ltd.), 150 g of ethyl acetate (manufactured by Kanto Chemical Co., Ltd.), and 150 g of pure water were placed. 29.99 g (129.2 mmol) of sodium dithionite (manufactured by Kanto Chemical Co., Ltd.) was stirred at 25 ° C for 20 hours. The aqueous phase was removed from the reaction liquid, washed with pure water, and then ethyl acetate was removed by an evaporator to obtain a brown solid of 14.29 g (81.1 mmol) of 1,4,5-trihydroxynaphthalene.

¹ H-NMR (500 MHz, DMSO-d ₆ ): 6.55 ppm (d, 1H), 6.65 ppm (d, 1H), 6.71 ppm (d, 1H), 7.22 ppm (t, 1H), 7.50 ppm (d, 1H), 9.33ppm (s, 1H), 10.32ppm (s, 1H), 10.69ppm (s, 1H)

Synthesis Example 1

Into a 50 ml eggplant-shaped flask, 0.90 g of 1,4,5-trihydroxynaphthalene, 0.78 g of 1-naphthaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), and 0.061 g of methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) were placed. Propylene glycol monomethyl ether 2.63g. Thereafter, the mixture was heated to 110 ° C and refluxed for about 14 hours. After the completion of the reaction, the mixture was diluted with 3.00 g of tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd.), and the precipitate was filtered and removed. The recovered filtrate was dropped into a hexane solution and allowed to precipitate. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure overnight at 85 °C. Then, 1.26 g of a 1,4,5-trihydroxynaphthalene resin as a dark blue powder was obtained. The obtained polymer corresponds to the formula (1-11). The weight average molecular weight measured by GPC in terms of polystyrene was Mw 2,200, and the polydispersity Mw/Mn was 1.75.

Synthesis Example 2

Into a 50 ml eggplant-shaped flask, 0.88 g of 1,4,5-trihydroxynaphthalene, 1.62 g of 1-nonylcarboxyaldehyde (manufactured by Aldrich), 1,4-dioxane (manufactured by Kanto Chemical Co., Ltd.), 10.52 g, p-toluene Acid monohydrate (manufactured by Tokyo Chemical Industry Co., Ltd.) was 0.14 g. Thereafter, the mixture was heated to 110 ° C and refluxed for about 16 hours. After the completion of the reaction, the mixture was diluted with tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd.) at 5.26 g, and the precipitate was removed by filtration. The recovered filtrate was dropped into a hexane solution and allowed to precipitate. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure overnight at 85 °C. Then, 1.48 g of a 1,4,5-trihydroxynaphthalene resin as a dark blue powder was obtained. The obtained polymer corresponds to the formula (1-41). The weight average molecular weight Mw measured by GPC in terms of polystyrene was 1,500, and the polydispersity Mw/Mn was 1.54.

Synthesis Example 3

In a 50 ml eggplant-shaped flask, 0.88 g of 1,4,5-trihydroxynaphthalene, 1-indolecarboxyl 0.81 g of aldehyde (made by Aldrich), 0.55 g of 1-naphthaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), 7.31 g of 1,4-dioxane (manufactured by Kanto Chemical Co., Ltd.), p-toluenesulfonic acid monohydrate (Tokyo) Chemical Industry Co., Ltd.) 0.14g. Thereafter, the mixture was heated to 110 ° C and refluxed for about 16 hours. After the completion of the reaction, the mixture was diluted with 4.74 g of tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd.), and the precipitate was removed by filtration. The recovered filtrate was dropped into a methanol/water mixed solution and precipitated. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure overnight at 85 °C. However, 1.28 g of a 1,4,5-trihydroxynaphthalene resin of a dark blue powder was obtained. The obtained polymer corresponds to the formula (1-46). The weight average molecular weight Mw measured by GPC in terms of polystyrene was 2,500, and the polydispersity Mw/Mn was 1.67.

Comparative Synthesis Example 1

Into a 100 ml eggplant-shaped flask, 11.21 g of 1,5-dihydroxynaphthalene, 1-naphthaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), 5.48 g, 1,4-dioxane (manufactured by Kanto Chemical Co., Ltd.) 45.04 g, p- Toluenesulfonic acid monohydrate (manufactured by Tokyo Chemical Industry Co., Ltd.) 1.34 g. Thereafter, the mixture was heated to 110 ° C and refluxed for about 23 hours. After the completion of the reaction, the mixture was diluted with 22.5 g of tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd.), and the precipitate was removed by filtration. The recovered filtrate was dropped into a methanol/water mixed solution and precipitated. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure overnight at 85 °C. Then, 8.03 g of a 1,5-dihydroxynaphthalene resin as a dark blue powder was obtained. The obtained polymer corresponds to the formula (3-1). The weight average molecular weight Mw measured by GPC in terms of polystyrene is 1,900, and the polydispersity Mw/Mn is 1.35.

Comparative Synthesis Example 2

In a 200 ml three-necked flask, 10.09 g of phloroglucinol (manufactured by Tokyo Chemical Industry Co., Ltd.), 18.42 g of 1-nonylcarboxyaldehyde (manufactured by Aldrich), and 1,4-dioxane (manufactured by Kanto Chemical Co., Ltd.) 49.61 g, p. -toluenesulfonic acid monohydrate (manufactured by Tokyo Chemical Industry Co., Ltd.) 4.56 g. Thereafter, the mixture was heated to 110 ° C and refluxed for about 5 hours. After the completion of the reaction, the mixture was diluted with tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd.) at 24.80 g, and the precipitate was removed by filtration. The recovered filtrate was dropped into a methanol/water mixed solution and precipitated. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure overnight at 85 °C. Then, 25.26 g of a benzenetriol resin was obtained between the brown powders. The obtained polymer corresponds to the formula (3-2). The weight average molecular weight Mw measured by GPC in terms of polystyrene was 2,800, and the polydispersity Mw/Mn was 2.18.

Example 1

1 g of the resin obtained in Synthesis Example 1 was dissolved in 1.35 g of propylene glycol monomethyl ether acetate, 1.15 g of propylene glycol monomethyl ether, and 9.19 g of cyclohexanone, and was prepared for use in a resist underlayer processed by photolithography of a multilayer film. The film forms a solution of the composition.

Example 2

1 g of the resin obtained in Synthesis Example 2 was dissolved in 1.35 g of propylene glycol monomethyl ether acetate, 1.15 g of propylene glycol monomethyl ether, and 9.19 g of cyclohexanone, and was prepared for use in a resist underlayer processed by photolithography of a multilayer film. The film forms a solution of the composition.

Example 3

1 g of the resin obtained in Synthesis Example 3 was dissolved in 1.35 g of propylene glycol monomethyl ether acetate, 1.15 g of propylene glycol monomethyl ether, and 9.19 g of cyclohexanone, and was prepared for use in a resist underlayer processed by photolithography of a multilayer film. Membrane forming composition Solution.

Comparative example 1

1 g of a cresol novolak resin (commercial product, weight average molecular weight: 4000) was dissolved in 10.34 g of propylene glycol monomethyl ether and 2.59 g of cyclohexanone to prepare a resist underlayer film which was processed by photolithography of a multilayer film. A solution of the composition is formed.

Comparative example 2

2 g of the resin (formula 3-1) obtained in Comparative Synthesis Example 1 was dissolved in 9.13 g of propylene glycol monomethyl ether acetate, 9.19 g of propylene glycol monomethyl ether, and 4.59 g of cyclohexanone, and was used for the formation of a multilayer film. The lithographically processed underlayer film forms a solution of the composition.

Comparative example 3

1 g of the resin (formula 3-2) obtained in Comparative Synthesis Example 2 was dissolved in 10.34 g of propylene glycol monomethyl ether and 2.59 g of cyclohexanone to prepare a composition for forming a resist underlayer film by photolithography of a multilayer film. Solution.

(Measurement of optical parameters)

The resist underlayer film solutions prepared in Examples 1 to 3 and Comparative Example 1 were applied onto a tantalum wafer using a spin coater. The underlayer film (film thickness) was formed by firing on a hot plate at 240 ° C for 1 minute, at 250 ° C for 1 minute, or at 400 ° C for 2 minutes (Comparative Example 1 was at 205 ° C for 1 minute). 0.05 μm). These resist underlayer films were measured using a spectroscopic ellipsometer at a refractive index (n value) at a wavelength of 193 nm and an optical absorptivity (k value, also referred to as an attenuation coefficient). The results are shown in Table 1.

(Dissolution test for photoresist solvent)

The solution of the composition for forming a resist underlayer film prepared in Examples 1 to 3 was applied onto a tantalum wafer using a spin coater. The film was fired at 240 ° C for 1 minute or at 400 ° C for 2 minutes on a hot plate to form a resist underlayer film (film thickness: 0.20 μm). These anti-corrosion underlayer films were subjected to an immersion test for a solvent used for resisting, for example, ethyl lactate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and cyclohexanone.

It was confirmed that the solutions of Examples 1 to 3 were subjected to firing at 240 ° C for 1 minute or at 400 ° C for 2 minutes, and were insoluble to these solvents.

(Measurement of dry etching speed)

The following can be used for the etcher and the etching gas used for the measurement of the dry etching rate.

RIE-10NR (made by SAMCO): CF ₄

The solutions of the resist underlayer film forming compositions prepared in Examples 1 to 3 and Comparative Example 1 were applied onto a tantalum wafer using a spin coater. The film was fired at 240 ° C for 1 minute, at 250 ° C for 1 minute, or at 400 ° C for 2 minutes on a hot plate (Comparative Example 1 was baked at 205 ° C for 1 minute) to form a resist underlayer film (film thickness: 0.20 μm). The dry etching rate using CF ₄ gas as an etching gas was measured.

The dry etching rate of the underlayer film of Comparative Example 1 and Examples 1 to 3 was compared from the obtained measured values. The results are shown in Table 2. The speed ratio (1) in the table is the dry etching rate ratio (the dry etching rate of the underlayer film used in Examples 1 to 3) / (the dry etching rate of Comparative Example 1).

(Measurement of bending resistance of the pattern)

The solutions of the respective underlayer film forming compositions adjusted in Examples 2 to 3 and Comparative Examples 2 to 3 were each applied onto a tantalum wafer with a ruthenium oxide film by using a spin coater. After baking at 240 ° C for 1 minute or 400 ° C for 2 minutes on a hot plate, a resist underlayer film (film thickness: 200 nm) was formed. Applying a hard mask to a resist underlayer film to form a composition solution (polyorganoprene) solution, and firing at 240 ° C for 1 minute to form a tantalum hard mask layer (polyorganosiloxane) The film thickness was 45 nm). A resist solution was applied thereon, and baked at 100 ° C for 1 minute to obtain a resist layer (film thickness: 120 nm). Exposure was carried out at a wavelength of 193 nm using a photomask, and after exposure, PEB was heated (at 105 ° C for 1 minute) to obtain a resist pattern by development. Thereafter, dry etching was performed using a fluorine-based gas (component: CF ₄ ), and the resist pattern was transferred to a hard mask. Thereafter, dry etching is performed using an oxygen-based gas (component is O ₂ ), and the resist pattern is transferred to the underlying resist underlayer film. Thereafter, dry etching is performed using a fluorine-based gas (component: C ₄ F ₈ ) to remove the cerium oxide film on the germanium wafer. The shape of each pattern at this time was observed by an electron microscope.

Although the bending of the irregular pattern called wigling is likely to occur depending on the narrowing of the width of the pattern, the above steps of forming the composition using the resist underlayer film of the above embodiment are started, and the pattern is started to be produced. The width of the pattern at the time of wiggling was observed by an electron microscope.

The substrate processing based on the faithful pattern cannot be performed due to the wiggling of the pattern, and it is necessary to perform the substrate processing by the pattern width (limit pattern width) before the generation of the wiggling of the pattern. The narrower the value of the width pattern of the pattern generated by the wiggling of the pattern, the more the processing of the fine substrate can be performed.

The resolution is measured using a length-measuring scanning electron microscope (Hitachi Made by the system). The measurement results are shown in Tables 3 and 4.

[Industrial availability]

The composition for forming a resist underlayer film used in photolithography processing of the multilayer film of the present invention is different from the past high etching rate anti-reflection film, and has a dry etching speed close to or close to the photoresist. The selection ratio is smaller than the semiconductor substrate, and the dry etching rate is smaller than the selection ratio, and further, a resist underlayer film which can serve as an effect of the antireflection film is further provided. Further, it was judged that the underlayer film forming composition of the present invention has heat resistance which can be formed by vapor deposition on the upper layer to form a hard mask. Moreover, even when the firing temperature is low, A good pattern of wiggling which is difficult to produce a pattern, a pattern width of at least around 36 nm is a good pattern without bending.

Claims (10)

A resist underlayer film forming composition for lithography characterized by containing a polymer having the formula (1): (In the formula (1), A is a unit structure represented by three hydroxyl groups derived from a hydroxy-substituted naphthylene group of a trihydroxy naphthalene, and B is a monovalent condensed aromatic hydrocarbon ring group in which two to four benzene rings are condensed) . The underlayer film forming composition of claim 1, wherein the condensed aromatic hydrocarbon ring group of B is a naphthalene ring group, an anthracene ring group, or an anthracene ring group. The underlayer film forming composition of claim 1 or 2, wherein the condensed aromatic hydrocarbon ring group of B has a halogen group, a hydroxyl group, a nitro group, an amine group, a carboxyl group, a carboxylate group, and a nitrile group as a substituent. , or these combinations. The underlayer film forming composition according to any one of claims 1 to 3, further comprising a crosslinking agent. The underlayer film forming composition according to any one of claims 1 to 4, further comprising an acid and/or an acid generator. A resist underlayer film characterized in that the resist underlayer film forming composition according to any one of claims 1 to 5 is applied onto a semiconductor substrate and fired. A method for forming a resist pattern, which is characterized in that it is used for the production of a semiconductor comprising the step of applying a resist underlayer film forming composition according to any one of claims 1 to 5 to a semiconductor. The step of forming a resist underlayer film on the substrate and firing. A method of manufacturing a semiconductor device, comprising the steps of forming a resist underlayer film on a semiconductor substrate by forming a composition of a resist underlayer film according to any one of claims 1 to 5; a step of forming a resist film, a step of forming a resist pattern by irradiation of light or electron lines and development, a step of etching the underlayer film by a formed resist pattern, and a pattern by patterning The step of processing the semiconductor substrate by the underlying resist film. A method of manufacturing a semiconductor device, comprising the steps of forming a resist underlayer film on a semiconductor substrate by forming a composition of a resist underlayer film according to any one of claims 1 to 5; a step of forming a hard mask, a step of forming a resist film thereon, a step of forming a resist pattern by irradiation of light or electron lines, and a hard mask by forming a resist pattern a step of etching, a step of etching the underlayer film by a patterned hard mask, and a step of processing the semiconductor substrate by the patterned resist underlayer film. The manufacturing method of claim 9, wherein the hard mask is formed by coating of an inorganic substance or vapor deposition of an inorganic substance.