WO2010041626A1

WO2010041626A1 - Composition for forming resist underlayer film for lithography, which contains fluorene-containing resin

Info

Publication number: WO2010041626A1
Application number: PCT/JP2009/067338
Authority: WO
Inventors: 徹也新城; 軍孫; 圭祐橋本
Original assignee: 日産化学工業株式会社
Priority date: 2008-10-10
Filing date: 2009-10-05
Publication date: 2010-04-15
Also published as: KR20110086812A; JPWO2010041626A1; TW201019048A

Abstract

A composition for forming a resist underlayer film which has heat resistance required for use in a lithography process during production of a semiconductor device. The composition for forming a resist underlayer film contains a polymer which contains a unit structure represented by formula (1). (In the formula, R₁, R₂, R₃ and R₄ each represents an alkyl group having 1-10 carbon atoms, an aryl group having 6-20 carbon atoms, a halogen group, a nitro group or an amino group; R₅ and R₆ each represents a hydrogen atom, an alkyl group having 1-10 carbon atoms or a glycidyl group; Ar represents an arylene group having 6-20 carbon atoms; and n1 and n2 each represents an integer of 0-4, n3 represents an integer from 0 to (6-n5), n4 represents an integer from 0 to (6-n6), and n5 and n6 each represents an integer of 1-6, with n3 + n5 being an integer of 1-6 and n4 + n6 being an integer of 1-6.)

Description

Lithographic resist underlayer film forming composition comprising a resin containing fluorene

The present invention relates to a resist underlayer film forming composition for lithography effective at the time of processing a semiconductor substrate, and a resist underlayer film for lithography formed therefrom. The present invention also relates to a resist pattern forming method including the resist underlayer film forming composition, and a semiconductor device manufacturing method including a step of processing a semiconductor substrate with the resist pattern.

Conventionally, in the manufacture of semiconductor devices, fine processing of a semiconductor substrate by lithography using a photoresist composition has been performed. The fine processing is, for example, forming a thin film made of a photoresist composition on a substrate to be processed such as a silicon wafer, and irradiating the thin film with actinic rays such as ultraviolet rays through a mask pattern in which a pattern of a semiconductor device is drawn. This is a processing method in which a substrate to be processed such as a silicon wafer is subjected to an etching process using a photoresist having a pattern formed by development as a protective film. However, in recent years, the degree of integration of semiconductor devices has increased, and the actinic rays used tend to be shortened from KrF excimer laser (248 nm) to ArF excimer laser (193 nm) and F ₂ excimer laser (157 nm). is there. Along with this, a serious problem has occurred due to the influence of diffuse reflection of active rays from the substrate and standing waves. Therefore, a method of providing an antireflection film (Bottom Anti-Reflective Coating, BARC) between the photoresist and the substrate to be processed has been widely studied.

In the future, when the resist pattern is further miniaturized, the resolution of the current resist film and the problem that the resist pattern collapses after development occur. Therefore, it is desired to further reduce the resist thickness. Therefore, it is difficult to obtain a resist pattern film thickness sufficient for substrate processing, and not only the resist pattern but also the resist underlayer film created between the resist and the semiconductor substrate to be processed functions as a mask during substrate processing. A process for providing Unlike conventional resist underlayer films with high etch rate (fast etching speed) as resist underlayer films for such processes, compared to resist underlayer films and resists for lithography, which have a selectivity of dry etching rate close to that of resist There is an increasing demand for a resist underlayer film for lithography having a low dry etching rate selection ratio and a resist underlayer film for lithography having a low dry etching rate selection ratio compared to a semiconductor substrate.

As a composition for forming a resist underlayer film as described above, a resist underlayer film forming composition using a fluorenephenol novolac resin (see, for example, Patent Document 1), a resist underlayer film forming composition using a fluorene naphthol novolak resin (For example, refer patent document 2) The resist underlayer film forming composition (for example, refer patent document 3 and patent document 4) containing resin which has fluorene phenol and aryl alkylene as a repeating unit structure is disclosed.
However, these lower layer films also do not satisfy all of the performance as a resist lower layer film as a mask during substrate processing, for example, solvent resistance, heat resistance, light absorbency, and selectivity of etching rate.

JP 2005-128509 A JP2007-199653A JP2007-178974 US Pat. No. 7,378,217

An object of the present invention is to provide a resist underlayer film forming composition for use in a lithography process for manufacturing a semiconductor device. Another object of the present invention is to provide an excellent resist pattern without intermixing with the resist layer, and has a dry etching rate close to that of the resist. It is an object of the present invention to provide a resist underlayer film for lithography having a selectivity ratio of 2 and a resist underlayer film for lithography having a selectivity ratio of a dry etching rate smaller than that of a semiconductor substrate. Another object of the present invention is to provide lithography having performance as an antireflection film that effectively absorbs reflected light from a substrate when fine processing of a resist underlayer film is performed by irradiation light having a wavelength of 248 nm, 193 nm, 157 nm, or the like. An object of the present invention is to provide a resist underlayer film and a composition for forming the same. Furthermore, the subject of this invention is providing the formation method of the resist pattern containing the resist underlayer film formed from a resist underlayer film formation composition. And it is providing the resist underlayer film which also has heat resistance, and the resist underlayer film forming composition for forming it.

As a first aspect of the present invention, the following formula (1):

(Wherein R ₁ and R ₂ are substituents on the fluorene ring, and R ₃ , R ₄ , OR ₅ , OR ₆ are substituents on the naphthalene ring. R ₁ , R ₂ , R ₃ , and R ₄ is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, a halogen group, a nitro group, or an amino group, and R ₅ and R ₆ are a hydrogen atom and 1 carbon atom, respectively. To an alkyl group of 10 to 10 or glycidyl group, Ar is an arylene group having 6 to 20 carbon atoms, n1 and n2 are each an integer of 0 to 4, and n3 is an integer of 0 to (6-n5) N4 is an integer from 0 to (6-n6), n5 and n6 are each an integer from 1 to 6, n3 + n5 is an integer from 1 to 6, and n4 + n6 is an integer from 1 to 6 A polymer containing a repeating unit structure represented by: A resist underlayer film-forming composition comprising
As a second aspect, in the formula (1), the resist underlayer film forming composition according to the first aspect, in which Ar represents a substituted or unsubstituted phenylene group, naphthylene group, biphenylene group, anthrylene group, or pyrene group,
As a third aspect, the resist underlayer film forming composition according to the first aspect or the second aspect further containing a crosslinking agent,
As a fourth aspect, the resist underlayer film forming composition according to the third aspect, wherein the crosslinking agent is a compound having an aromatic ring,
As a fifth aspect, the cross-linking agent is a compound represented by the following formula (2) or a polymer or oligomer having a repeating unit structure of the following formula (3):

(In the formula (2), R ₇ and R ₈ each represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms, n7 is an integer of 1 to 4, n8 is an integer of 1 to (5-n7), and n7 + n8 is an integer of 2 to 5. In formula (3), R ₉ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ₁₀ Is an alkyl group having 1 to 10 carbon atoms, n9 is an integer of 1 to 4, n10 is 0 to (4-n9), and n9 + n10 is an integer of 1 to 4. Repeating oligomers and polymers The number m of unit structures is 2 to 100.) The resist underlayer film forming composition according to the third aspect,
As a sixth aspect, the resist underlayer film forming composition according to any one of the first aspect to the fifth aspect, which further contains an acid or an acid generator,
As a seventh aspect, a resist underlayer film obtained by applying and baking the resist underlayer film forming composition according to any one of the first to sixth aspects on a semiconductor substrate,
As an eighth aspect, the resist underlayer film forming composition according to any one of the first to sixth aspects is applied on a semiconductor substrate and baked to form a lower layer film. Forming a resist pattern;
As a ninth aspect, a step of forming an underlayer film made of the resist underlayer film forming composition according to any one of the first to sixth aspects on a semiconductor substrate, and forming a resist film on the underlayer film Forming a resist pattern by light and electron beam irradiation and development on the resist film, etching the lower layer film with the resist pattern, and processing a semiconductor substrate with the patterned lower layer film A method for manufacturing a semiconductor device,
As a tenth aspect, a step of forming an underlayer film made of the resist underlayer film forming composition according to any one of the first to sixth aspects on a semiconductor substrate, a step of forming a hard mask on the underlayer film, Further, a step of forming a resist film on the hard mask, a step of forming a resist pattern on the resist film by light and electron beam irradiation and development, a step of etching the hard mask with the resist pattern, the patterned The present invention relates to a method for manufacturing a semiconductor device, including a step of etching the lower layer film with a hard mask and a step of processing a semiconductor substrate with the patterned lower layer film.

The resist underlayer film formed from the resist underlayer film forming composition of the present invention can form a good resist pattern shape without causing intermixing with the upper layer portion of the resist underlayer film.
The resist underlayer film formed from the resist underlayer film forming composition of the present invention can be provided with the ability to efficiently absorb the reflected light from the substrate, and can also have an effect as an antireflection film. .
The resist underlayer film forming composition of the present invention has an excellent dry etching rate selectivity close to that of the resist, a low dry etching rate selectivity compared to the resist, and a low dry etching rate selectivity compared to the semiconductor substrate. A resist underlayer film can be formed.

As the resist pattern is miniaturized, the resist is thinned to prevent the resist pattern from falling after development. In the manufacture of a semiconductor substrate device having such a thin film resist, the resist pattern is transferred to the lower layer film by an etching process, and the substrate processing is performed using the lower layer film to which the pattern is transferred as a mask, or the resist pattern is etched. The process includes transferring the pattern to the lower layer film in the process, and further transferring the pattern transferred to the lower layer film to the lower layer film using a different gas composition, and finally processing the substrate. The resist underlayer film and the composition for forming the same of the present invention are effective as an underlayer film for this process. When a substrate is processed using the resist underlayer film of the present invention, a processed substrate (for example, a thermal silicon oxide film on the substrate). , Silicon nitride film, polysilicon film, and the like).

The resist underlayer film of the present invention can be used as a planarizing film, a resist underlayer film, a resist layer antifouling film, or a film having dry etch selectivity. Thereby, by using the resist underlayer film of the present invention, a resist pattern can be easily and accurately formed in the lithography process of semiconductor manufacturing.
A resist underlayer film formed from the resist underlayer film forming composition according to the present invention is formed on a substrate, a hard mask is formed thereon, a resist film is formed thereon, and the resist film is exposed and developed by exposure and development. Process for forming a pattern, transferring the resist pattern to a hard mask, transferring the resist pattern transferred to the hard mask to the resist underlayer film, and processing the semiconductor substrate with the resist pattern transferred to the resist underlayer film There is. The hard mask used in this process may be formed by applying a composition containing an organic polymer and / or an inorganic polymer and a solvent, or may be formed by vacuum deposition of an inorganic substance. In the method of vacuum-depositing an inorganic substance (for example, silicon nitride oxide), the temperature of the resist underlayer film surface rises to around 400 ° C. when the deposit is deposited on the resist underlayer film surface. Therefore, the resist underlayer film used in the vacuum deposition method needs heat resistance. The polymer constituting the resist underlayer film forming composition of the present invention is a copolymer containing a repeating unit structure of fluorene naphthol and arylene alkylene. Therefore, the heat resistance is extremely high, and thermal deterioration does not occur when depositing a deposit in the vacuum deposition method.

The present invention is a resist underlayer film forming composition for lithography containing a polymer containing a repeating unit structure represented by the formula (1). In this invention, the said polymer and a solvent are included. Furthermore, a crosslinking agent and an acid can be included, and additives such as an acid generator and a surfactant can be included as necessary. The solid content of the composition is 0.1 to 70% by mass, or 0.1 to 60% by mass. Solid content is the content rate of all the components remove | excluding the solvent from the resist underlayer film forming composition. The polymer can be contained in the solid content in a proportion of 1 to 100% by mass, or 1 to 99% by mass, or 50 to 99% by mass.

The polymer used in the present invention has a weight average molecular weight of 600 to 1000000, preferably 1000 to 200000. If the average molecular weight is less than 600, sufficient hardness may not be obtained at the time of curing, and if the average molecular weight is greater than 1000000, the viscosity may become high and handling may be difficult.

The polymer used in the present invention includes a repeating unit structure represented by the following formula (1).

In the formula, R ₁ and R ₂ represent substituents on the fluorene ring, and R ₃ , R ₄ , OR ₅ , and OR ₆ represent substituents on the naphthalene ring. R ₁ , R ₂ , R ₃ , and R ₄ each represent an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, a halogen group, a nitro group, or an amino group, and R ₅ , R ₆ represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a glycidyl group, Ar represents an arylene group having 6 to 20 carbon atoms, and n1 and n2 are each an integer of 0 to 4, n3 is an integer from 0 to (6-n5), n4 is an integer from 0 to (6-n6), n5 and n6 are each an integer from 1 to 6, and n3 + n5 is an integer from 1 to 6 N4 + n6 is an integer from 1 to 6.

Examples of the alkyl group having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, cyclopropyl group, n-butyl group, i-butyl group, s-butyl group, t- Butyl, cyclobutyl, 1-methyl-cyclopropyl, 2-methyl-cyclopropyl, n-pentyl, 1-methyl-n-butyl, 2-methyl-n-butyl, 3-methyl-n -Butyl group, 1,1-dimethyl-n-propyl group, 1,2-dimethyl-n-propyl group, 2,2-dimethyl-n-propyl group, 1-ethyl-n-propyl group, cyclopentyl group, 1 -Methyl-cyclobutyl group, 2-methyl-cyclobutyl group, 3-methyl-cyclobutyl group, 1,2-dimethyl-cyclopropyl group, 2,3-dimethyl-cyclopropyl group, 1-ethyl-cyclo Propyl, 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 group, 1,2-dimethyl-n-butyl group, 1,3-dimethyl-n-butyl group, 2,2-dimethyl-n-butyl group, 2,3- Dimethyl-n-butyl group, 3,3-dimethyl-n-butyl group, 1-ethyl-n-butyl group, 2-ethyl-n-butyl group, 1,1,2-trimethyl-n-propyl group, 1 , 2,2-trimethyl-n-propyl group, 1-ethyl-1-methyl-n-propyl group, 1-ethyl-2-methyl-n-propyl group, cyclohexyl group, 1-methyl-cyclopentyl group, 2- Methyl-cyclopentyl group, 3-methyl-thio Lopentyl group, 1-ethyl-cyclobutyl group, 2-ethyl-cyclobutyl group, 3-ethyl-cyclobutyl group, 1,2-dimethyl-cyclobutyl group, 1,3-dimethyl-cyclobutyl group, 2,2-dimethyl-cyclobutyl group 2,3-dimethyl-cyclobutyl group, 2,4-dimethyl-cyclobutyl group, 3,3-dimethyl-cyclobutyl group, 1-n-propyl-cyclopropyl group, 2-n-propyl-cyclopropyl group, 1- i-propyl-cyclopropyl group, 2-i-propyl-cyclopropyl group, 1,2,2-trimethyl-cyclopropyl group, 1,2,3-trimethyl-cyclopropyl group, 2,2,3-trimethyl- Cyclopropyl group, 1-ethyl-2-methyl-cyclopropyl group, 2-ethyl-1-methyl-cyclopropyl group, 2-ethyl Examples include a -2-methyl-cyclopropyl group and a 2-ethyl-3-methyl-cyclopropyl group.

Examples of the aryl group having 6 to 20 carbon atoms include phenyl group, o-methylphenyl group, m-methylphenyl group, p-methylphenyl group, o-chlorophenyl group, m-chlorophenyl group, and p-chlorophenyl group. O-fluorophenyl group, p-fluorophenyl group, o-methoxyphenyl group, p-methoxyphenyl group, p-nitrophenyl group, p-cyanophenyl group, α-naphthyl group, β-naphthyl group, o-biphenylyl Group, m-biphenylyl group, p-biphenylyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group and 9-phenanthryl group Groups and the like.

The halogen group includes fluorine, chlorine, bromine, iodine and the like.

Examples of the arylene group having 6 to 20 carbon atoms include phenylene group, naphthylene group, biphenylene group, anthrylene group, pyrene group and derivatives thereof. Examples of the arylene group derivative include arylene group derivatives substituted with an alkyl group having 1 to 10 carbon atoms, a halogen group, a nitro group, or an amino group.

The polymer containing the repeating unit structure represented by the formula (1) is prepared by reacting, for example, a fluorene compound having a naphthol group and dimethoxymethylbenzene in the presence of an acid catalyst (for example, paratoluenesulfonic acid) at a temperature of about 130 to 180 ° C. For 1 to 10 hours.

Particularly preferred polymers containing a repeating unit structure represented by the formula (1) are obtained by reacting 9,9-bis [(poly) hydroxynaphthyl] fluorenes, bisalkoxyalkylbenzenes, or dihalogenated methylanthracenes. And polymers that can be used.
Examples of 9,9-bis [(poly) hydroxynaphthyl] fluorenes include 9,9-bis (hydroxynaphthyl) fluorenes such as 9,9-bis [6- (2-hydroxynaphthyl)] fluorene (6, 6- (9-fluorenylidene) -di (2-naphthol)), 9,9-bis [1- (5-hydroxynaphthyl)] fluorene (5,5- (9-fluorenylidene) -di (1-naphthol)) Etc.
Examples of bisalkoxyalkylbenzenes include 1,4-bismethoxymethylbenzene.
Examples of the dihalogenated methylanthracenes include 9,10-bis (chloromethyl) anthracene.

The above polymer can be mixed with a polymer composed of another repeating unit structure within 30% by mass in the whole polymer.

Polymers that can be mixed include polyacrylic acid ester compounds, polymethacrylic acid ester compounds, polyacrylamide compounds, polymethacrylamide compounds, polyvinyl compounds, polystyrene compounds, polymaleimide compounds, polymaleic anhydrides, and polyacrylonitrile compounds. Can be mentioned.

Examples of the raw material monomer for the polyacrylate compound include methyl acrylate, ethyl acrylate, isopropyl acrylate, benzyl acrylate, naphthyl acrylate, anthryl acrylate, anthryl methyl acrylate, 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, methoxytriethylene 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, Examples include 8-ethyl-8-tricyclodecyl acrylate and 5-acryloyloxy-6-hydroxynorbornene-2-carboxyl-6-lactone.

The raw material monomers for the polymethacrylic acid ester compound include ethyl methacrylate, normal propyl methacrylate, normal pentyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, naphthyl methacrylate, anthryl methacrylate, anthryl methyl methacrylate, phenyl methacrylate, 2-phenylethyl methacrylate, 2 -Hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,2-trichloroethyl methacrylate, methyl acrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, normal lauryl methacrylate Normal stearyl methacrylate Methoxydiethylene glycol methacrylate, methoxypolyethylene glycol methacrylate, tetrahydrofurfuryl methacrylate, isobornyl methacrylate, tert-butyl methacrylate, isostearyl methacrylate, normal 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-tri Cyclodecyl methacrylate, 5-methacryloyloxy-6-hydroxynorbornene-2-carboxyl 6-lactone, and 2,2,3,3,4,4,4-heptafluoro-butyl methacrylate, and the like.

Examples of the acrylamide compound include acrylamide, N-methylacrylamide, N-ethylacrylamide, N-benzylacrylamide, N-phenylacrylamide, and N, N-dimethylacrylamide.

Examples of the raw material monomer of the polymethacrylic acid amide compound include methacrylamide, N-methyl methacrylamide, N-ethyl methacrylamide, N-benzyl methacrylamide, N-phenyl methacrylamide, and N, N-dimethyl methacrylamide. .

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

Examples of the raw material monomer for the polystyrene compound include styrene, methylstyrene, chlorostyrene, bromostyrene, and hydroxystyrene.

Examples of the raw material monomer of the polymaleimide compound include maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide.

The above polymer dissolves an addition polymerizable monomer and a chain transfer agent added as necessary in an organic solvent, and then adds a polymerization initiator to conduct a polymerization reaction, and then adds a polymerization terminator to stop the polymerization reaction. Can be manufactured. The addition amount of the chain transfer agent is 10% or less with respect to the mass of the monomer, the addition amount of the polymerization initiator is 1 to 10% with respect to the mass of the monomer, and the addition amount of the polymerization terminator is 0. 0.01 to 0.2% by mass.
Examples of the organic solvent used include propylene glycol monomethyl ether, propylene glycol monopropyl ether, ethyl lactate, cyclohexanone, methyl ethyl ketone, and dimethylformamide. Examples of the chain transfer agent include dodecane thiol and dodecyl thiol. Examples of the agent include azobisisobutyronitrile and azobiscyclohexanecarbonitrile, and examples of the polymerization terminator include 4-methoxyphenol. The reaction conditions are appropriately selected from a temperature of 30 to 100 ° C. and a reaction time of 1 to 48 hours.

The resist underlayer film forming composition of the present invention can contain a crosslinking agent. Examples of the cross-linking agent include melamine-based, substituted urea-based, or polymer systems thereof. Preferably, a cross-linking agent having at least two cross-linking substituents, such as methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxymethylated benzoguanamine , Methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, or methoxymethylated thiourea. Moreover, the condensate of these compounds can also be used.

Moreover, it is preferable to use a crosslinking agent having high heat resistance as the crosslinking agent. As the crosslinking agent having high heat resistance, a compound containing a crosslinking forming substituent having an aromatic ring (for example, a benzene ring or a naphthalene ring) in the molecule can be used. Examples thereof include a compound represented by the following formula (2), or a polymer or oligomer having a repeating unit structure represented by the following formula (3).

In the formula (2), R ₇ and R ₈ each represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms, n7 is an integer of 1 to 4, Is an integer from 1 to (5-n7), and n7 + n8 is an integer from 2 to 5.
In formula (3), R ₉ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, R ₁₀ represents an alkyl group having 1 to 10 carbon atoms, n9 is an integer of 1 to 4, and n10 Is 0 to (4-n9), and n9 + n10 is an integer of 1 to 4. The number m of the repeating unit structure of the oligomer and polymer is in the range of 2 to 100, preferably 2 to 50.

In formula (2) and formula (3), examples of the alkyl group having 1 to 10 carbon atoms and the aryl group having 6 to 20 carbon atoms include the alkyl group and aryl group defined in formula (1) above. Can do.
The compound represented by the formula (2) and the polymer or oligomer represented by the formula (3) are exemplified below.

The above compounds can be obtained as products of Asahi Organic Materials Industry Co., Ltd. and Honshu Chemical Industry Co., Ltd. For example, among the above-mentioned crosslinking agents, the compound of the formula (4-21) can be obtained as Asahi Organic Materials Co., Ltd., trade name TM-BIP-A.

The amount of the crosslinking agent to be added varies depending on the coating solvent used, the base substrate used, the required solution viscosity, the required film shape, etc., but is 0.001 to 80% by mass with respect to the total solid content, preferably The amount is 0.01 to 50% by mass, more preferably 0.05 to 40% by mass. If the addition amount of the crosslinking agent is less than 0.01% by mass, a sufficient number of crosslinking points may not be generated, and intermixing with the resist layer may occur. Moreover, when the addition amount of a crosslinking agent exceeds 80 mass%, sufficient antireflection effect may not be obtained.

These cross-linking agents may cause a cross-linking reaction by self-condensation, but when a cross-linkable substituent is present in the polymer of the present invention, it can cause a cross-linking reaction with those cross-linkable substituents.

In the present invention, as a catalyst for promoting the crosslinking reaction, p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonic acid, salicylic acid, sulfosalicylic acid, citric acid, benzoic acid, hydroxybenzoic acid, and naphthalene are used. Mix acidic compounds such as carboxylic acids or thermal acid generators such as 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, and other organic sulfonic acid alkyl esters. Can do. The blending amount is 0.0001 to 20% by mass, preferably 0.0005 to 10% by mass, preferably 0.01 to 3% by mass, based on the total solid content.

In the resist underlayer film forming composition of the present invention, a photoacid generator can be added in order to match the acidity with the photoresist coated on the upper layer in the lithography process. Preferred photoacid generators include, for example, onium salt photoacid generators such as bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate, and phenyl-bis (trichloromethyl) -s. -Halogen-containing compound photoacid generators such as triazine, and sulfonic acid photoacid generators such as benzoin tosylate and N-hydroxysuccinimide trifluoromethanesulfonate. The amount of the photoacid generator is 0.2 to 10% by weight, preferably 0.4 to 5% by weight, based on the total solid content.

In addition to the above, a light absorber, a rheology modifier, an adhesion aid, a surfactant, and the like can be further added to the resist underlayer film forming composition of the present invention as necessary.

The light absorber is added mainly for the purpose of further improving the light absorbency of the resist underlayer film and further enhancing the effect as an antireflection film. Examples of the light absorber include commercially available light absorbers described in “Technical Dye Technology and Market” (published by CMC) or “Dye Handbook” (edited by the Society of Synthetic Organic Chemistry), for example, C.I. I. Disperse Yellow 1, 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; C.I. I. Disperse Orange 1, 5, 13, 25, 29, 30, 31, 44, 57, 72 and 73; C.I. I. Disperse Red 1, 5, 7, 13, 17, 19, 43, 50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199 and 210; I. Disperse Violet 43; C.I. I. Disperse Blue 96; C.I. I. Fluorescent Brightening Agent 112, 135 and 163; C.I. I. Solvent Orange 2 and 45; C.I. I. Solvent Red 1, 3, 8, 23, 24, 25, 27 and 49; I. Pigment Green 10; and C.I. I. Pigment Brown 2 etc. can be used suitably. The above light-absorbing agent is usually blended at a ratio of 10% by mass or less, preferably 5% by mass or less, based on the total solid content of the resist underlayer film forming composition for lithography.

The rheology modifier mainly improves the fluidity of the resist underlayer film forming composition, and improves the film thickness uniformity of the resist underlayer film and the fillability of the resist underlayer film forming composition inside the hole, particularly in the baking process. It is added for the purpose of enhancing. Specific examples include phthalic acid derivatives such as dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, and butyl isodecyl phthalate; adipic acid derivatives such as dinormal butyl adipate, diisobutyl adipate, diisooctyl adipate, and octyl decyl adipate , Maleic acid derivatives such as dinormal butyl maleate, diethyl maleate, and dinonyl maleate, oleic acid derivatives such as methyl oleate, butyl oleate, and tetrahydrofurfuryl oleate, and stearic acid derivatives such as normal butyl stearate and glyceryl stearate Can be mentioned. These rheology modifiers are usually blended at a ratio of less than 30% by mass with respect to the total solid content of the resist underlayer film forming composition for lithography.

The adhesion auxiliary agent is added mainly for the purpose of improving the adhesion between the substrate or resist and the resist underlayer film, and for preventing the resist from peeling particularly during the development process. Specific examples include chlorosilanes such as trimethylchlorosilane, dimethylvinylchlorosilane, methyldiphenylchlorosilane, and chloromethyldimethylchlorosilane, trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethylvinylethoxysilane, diphenyldimethoxysilane, And alkoxysilanes such as phenyltriethoxysilane, hexamethyldisilazane, N, N′-bis (trimethylsilyl) urea, silazanes such as dimethyltrimethylsilylamine, and trimethylsilylimidazole, vinyltrichlorosilane, γ-chloropropyltrimethoxysilane , Silanes such as γ-aminopropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane, benzotriazole, Imidazole, indazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, urazole, thiouracil, and heterocyclic compounds such as mercaptoimidazole, mercaptopyrimidine, and 1,1-dimethylurea and 1 And urea such as 1,3-dimethylurea, and thiourea compounds. These adhesion assistants are usually blended in a proportion of less than 5% by mass, preferably less than 2% by mass, based on the total solid content of the resist underlayer film forming composition for lithography.

In the resist underlayer film for lithography of the present invention, there is no occurrence of pinholes or installations, and a surfactant can be blended in order to further improve the coating property against surface unevenness. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octyl phenol ether, and polyoxyethylene Polyoxyethylene alkyl allyl ethers such as ethylene nonylphenol ether, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and Sorbitan fatty acid esters such as sorbitan tristearate, polyoxyethylene sorbitan monolaurate, polyoxy Nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as tylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate, and EFTOP EF301 , EF303, EF352 (trade name, manufactured by Tochem Products Co., Ltd.), MegaFuck F171, F173, R-30 (trade name, manufactured by Dainippon Ink Co., Ltd.), Fluorard FC430, FC431 (manufactured by Sumitomo 3M Co., Ltd.) ), Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (trade name, manufactured by Asahi Glass Co., Ltd.), etc., organosiloxy Nporima KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), and the like. The compounding amount of these surfactants is usually 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 alone or in combination of two or more.

In the present invention, the solvent for dissolving the polymer, the crosslinking agent component, the crosslinking formation catalyst and the like include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl 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 acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-hydroxypropion Ethyl acetate, 2-hydroxy -Ethyl 2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, 3-ethoxy Methyl propionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate and the like can be used. These organic solvents can be used alone or in combination of two or more.

Furthermore, a high boiling point solvent can be mixed and used as a solvent. Examples thereof include propylene glycol monobutyl ether, propylene glycol monobutyl ether acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, and cyclohexanone. Use of these high-boiling solvents is preferable for improving the leveling property.

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

As the photoresist formed on the upper part of the resist underlayer film for lithography in the present invention, either negative type or positive type can be used. For example, a positive type photoresist composed of novolak resin and 1,2-naphthoquinonediazide sulfonic acid ester, acid A chemically amplified photoresist comprising a binder having a group that increases the alkali dissolution rate by decomposition by a photoacid generator, a low molecular weight compound that increases the alkali dissolution rate of the photoresist by decomposition with an alkali-soluble binder and acid, and light Chemically amplified photoresist comprising an acid generator, a binder having a group that is decomposed by an acid to increase the alkali dissolution rate, and a low molecular weight compound and a photoacid generator that are decomposed by an acid to increase the alkali dissolution rate of the photoresist Chemically amplified photoresist and bone Photoresist or the like having a Si atom. For example, trade name APEX-E manufactured by Rohm and Hearts may be mentioned.

In addition, the composition for forming an electron beam resist formed on the upper layer of the resist underlayer film for lithography in the present invention includes, for example, irradiation with a resin containing a Si—Si bond in the main chain and an aromatic ring at the terminal and an electron beam. A composition comprising an acid generator that generates an acid, or a poly (p-hydroxystyrene) having a hydroxyl group substituted with an organic group containing N-carboxyamine and an acid generator that generates an acid upon irradiation with an electron beam Examples thereof include compositions.

Further, in the electron beam resist, the site substituted with N-carboxyamine of the polymer side chain by the acid generated from the acid generator by electron beam irradiation becomes a hydroxyl group and exhibits alkali solubility. Therefore, the portion irradiated with the electron beam is dissolved in the alkaline developer to form a resist pattern. Examples of acid generators that generate an acid upon irradiation with this electron beam include 1,1-bis [p-chlorophenyl] -2,2,2-trichloroethane, 1,1-bis [p-methoxyphenyl] -2,2, Halogenated organic compounds such as 2-trichloroethane, 1,1-bis [p-chlorophenyl] -2,2-dichloroethane, and 2-chloro-6- (trichloromethyl) pyridine, triphenylsulfonium salts, and diphenyliodonium Examples thereof include onium salts such as salts, and sulfonic acid esters such as nitrobenzyl tosylate and dinitrobenzyl tosylate.

Examples of the developer used in the present invention include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, inorganic alkalis such as aqueous ammonia, ethylamine, and n-propylamine. Primary amines, secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxy An aqueous solution of an alkali such as quaternary ammonium salts such as copper, tetraethylammonium hydroxide and choline, and cyclic amines such as pyrrole and piperidine can be used. Furthermore, an appropriate amount of an alcohol such as isopropyl alcohol or a nonionic surfactant may be added to the alkaline aqueous solution. Of these, preferred developers are quaternary ammonium salts, more preferably tetramethylammonium hydroxide and choline.

Next, the resist pattern forming method of the present invention will be described. After applying a resist underlayer film forming composition on a substrate (eg, a transparent substrate such as a silicon / silicon dioxide coating, a glass substrate, an ITO substrate) used for manufacturing a precision integrated circuit element by an appropriate coating method such as a spinner or a coater. Bake and cure to create a resist underlayer film. Here, the thickness of the resist underlayer film is preferably 0.01 to 3.0 μm. The conditions for baking after coating are 80 to 350 ° C. and 0.5 to 120 minutes. Then, after forming a film on the resist underlayer film directly on the resist underlayer film or using one to several layers as required, a resist composition is applied and cured to form a resist film. A good resist pattern can be obtained by irradiating the resist with light or an electron beam through a predetermined mask, developing, rinsing and drying. If necessary, post-irradiation heating (PEB: Post Exposure Bake) may be performed. Then, using the resist in which the pattern is formed, the resist underlayer film is removed by dry etching to form a pattern, and using the resist underlayer film in which the pattern is formed, a desired pattern can be formed on the substrate. .

The exposure light used in the photoresist is actinic radiation such as near ultraviolet light, far ultraviolet light, or extreme ultraviolet light (for example, EUV), for example, 248 nm (KrF laser light), 193 nm (ArF laser light), or 157 nm. Light having a wavelength such as (F ₂ laser light) is used. The light irradiation can be used without particular limitation as long as it is a method capable of generating an acid from a photoacid generator, 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, for example, an electron beam irradiation apparatus can be used for electron beam irradiation to the electron beam resist.

In the present invention, a resist underlayer film forming composition is formed on a semiconductor substrate, a resist underlayer film is formed on the resist underlayer film, and a resist pattern is formed on the resist film by light or electron beam irradiation and development. A semiconductor device can be manufactured through a step of etching, a step of etching the resist underlayer film with a resist pattern, and a step of processing a semiconductor substrate with the patterned resist underlayer film.

In the future, as the miniaturization of the resist pattern progresses, there arises a problem of resolution and a problem that the resist pattern collapses after development. Therefore, it is desired to reduce the thickness of the resist. For this reason, it is difficult to obtain a resist pattern film thickness sufficient for substrate processing, and not only the resist but also the resist underlayer film formed between the resist and the semiconductor substrate to be processed has a function as a mask during substrate processing. It was necessary to make it. Therefore, a new process for forming a pattern on the resist underlayer film is required. As a resist underlayer film for such a process, unlike a conventional high etch rate resist underlayer film, a resist underlayer film for lithography having a selectivity of a dry etching rate close to that of a resist, a dry etching rate lower than that of a resist. Therefore, a lithography resist underlayer film having a selection ratio of ## EQU2 ## or a lithography resist underlayer film having a selectivity of a dry etching rate smaller than that of a semiconductor substrate is required. Further, such a resist underlayer film can be provided with an antireflection ability, and can also have a function of a conventional antireflection film.

In the present invention, after forming the resist underlayer film of the present invention on a substrate, one or several coating film materials are applied directly on the resist underlayer film or on the resist underlayer film as necessary. Thereafter, a resist composition can be applied to form a resist. Thus, when a fine pattern is formed on the resist, the substrate can be processed by selecting an appropriate etching gas even when the resist is thinly coated to prevent pattern collapse.

That is, a step of forming a resist underlayer film composed of a resist underlayer film forming composition on a semiconductor substrate, a step of forming a hard mask with a coating material containing a silicon component or the like thereon, and a resist film formed thereon A step, a step of forming a resist pattern by light and electron beam irradiation and development on the resist film, a step of etching the hard mask with the resist pattern, a step of etching the resist underlayer film with the patterned hard mask A semiconductor device can be manufactured through a step of processing the semiconductor substrate with the patterned resist underlayer film.

The resist underlayer film for lithography of the present invention has a high effect as an antireflection film because a light absorption site having sufficient light absorption performance is incorporated into the skeleton. Further, unlike an antireflection film to which a conventional light absorber is added, there is also an advantage that there is no diffused material in the photoresist during heating and drying.

The resist underlayer film for lithography of the present invention has high thermal stability, can prevent contamination of the upper layer film by decomposition products during baking, and can provide a margin for the temperature margin of the baking process. is there.

Furthermore, the resist underlayer film for lithography according to the present invention has a function of preventing reflection of light depending on process conditions, and further prevents the interaction between the substrate and the photoresist or applies to the material used for the photoresist or the photoresist. It can be used as a film having a function of preventing an adverse effect on a substrate of a substance generated during exposure.

Synthesis example 1
Into a reactor equipped with a stirrer, a cooler, and a nitrogen gas introduction tube, 16.6 g (0.1 mol) of 1,4-bis-methoxymethylbenzene and 6,6- (9-fluorenylidene) -di (2-naphthol) 45 0.1 g (0.1 mol) was added and 0.35 g of paratoluenesulfonic acid was added, followed by reaction at 160 ° C. for 5 hours. Methanol produced during the reaction was removed out of the system. After the reaction, it was washed with water and then dried under heating and reduced pressure to remove moisture and unreacted monomers. The residue was dissolved in propylene glycol monomethyl ether acetate and dropped into methanol for reprecipitation to obtain a fluorene resin represented by the following formula (5-1). The weight average molecular weight was 10,000.

Synthesis example 2
A reactor equipped with a stirrer, a cooler, and a nitrogen gas inlet tube was charged with 16 g of methyl isobutyl ketone, 27.5 g (0.1 mol) of 9,10-bis (chloromethyl) anthracene and 6,6- (9-fluorenylidene) as solvents. ) -Di (2-naphthol) 45.1 g (0.1 mol) was added, and 4.5 g of 35% hydrochloric acid was added, followed by reaction under reflux for 20 hours with stirring. After the reaction, it was washed with water and then dried under heating and reduced pressure to remove moisture and unreacted monomers. The residue was dissolved in propylene glycol monomethyl ether acetate, dropped into methanol and reprecipitated to obtain a fluorene resin represented by the following formula (5-2). The weight average molecular weight was 4000.

Synthesis example 3
To the reactor, 180 g of 4,4 ′-(9H-fluorene-9-ylidene) bisphenol, 75 g of 37% formalin aqueous solution, and 5 g of oxalic acid were added and stirred at 100 ° C. for 24 hours with stirring. After the reaction, the product was dissolved in 500 ml of methyl isobutyl ketone, the catalyst was removed by washing with sufficient water, and the solvent, water and unreacted monomers were removed by drying under reduced pressure to obtain a fluorene resin represented by the following formula (5-3). The weight average molecular weight was 11000.

Example 1
To 5 g of the fluorene resin represented by the formula (5-1) obtained in Synthesis Example 1 was mixed 0.015 g of Megafac R-30 (trade name, manufactured by Dainippon Ink & Chemicals, Inc.) as a surfactant. A solution was prepared by dissolving in 58 g of propylene glycol monomethyl ether acetate. Thereafter, the solution is filtered using a polyethylene microfilter having a pore size of 0.10 μm, and further filtered using a polyethylene microfilter having a pore size of 0.05 μm, so that the resist underlayer film forming composition solution used in the lithography process using a multilayer film is used. Was prepared.

Example 2
To 5 g of the fluorene resin represented by the formula (5-1) obtained in Synthesis Example 1, a compound represented by the formula (4-21) as a crosslinking agent (manufactured by Asahi Organic Materials Co., Ltd., trade name: TM- BIP-A) 0.5 g, pyridinium p-toluenesulfonate 0.005 g as a catalyst, and MegaFac R-30 (trade name, manufactured by Dainippon Ink Chemical Co., Ltd.) 0.015 g as a surfactant are mixed with propylene glycol. A solution was prepared by dissolving in 58 g of monomethyl ether acetate. Thereafter, the solution is filtered using a polyethylene microfilter having a pore size of 0.10 μm, and further filtered using a polyethylene microfilter having a pore size of 0.05 μm, so that the resist underlayer film forming composition solution used in the lithography process using a multilayer film is used. Was prepared.

Example 3
To 5 g of the fluorene resin represented by the formula (5-1) obtained in Synthesis Example 1, 0.5 g of tetramethoxymethyl glycoluril (trade name Powder Link 1174, manufactured by Mitsui Cytec Co., Ltd.) as a crosslinking agent and pyridinium as a catalyst 0.005 g of paratoluene sulfonate and 0.015 g of Megafac R-30 (trade name, manufactured by Dainippon Ink Chemical Co., Ltd.) as a surfactant were mixed and dissolved in 58 g of propylene glycol monomethyl ether acetate to obtain a solution. Thereafter, the solution is filtered using a polyethylene microfilter having a pore size of 0.10 μm, and further filtered using a polyethylene microfilter having a pore size of 0.05 μm, so that the resist underlayer film forming composition solution used in the lithography process using a multilayer film is used. Was prepared.

Example 4
To 5 g of the fluorene resin represented by the formula (5-2) obtained in Synthesis Example 2, 0.015 g of Megafac R-30 (trade name, manufactured by Dainippon Ink Chemical Co., Ltd.) as a surfactant was mixed. A solution was prepared by dissolving in 58 g of propylene glycol monomethyl ether acetate. Thereafter, the solution is filtered using a polyethylene microfilter having a pore size of 0.10 μm, and further filtered using a polyethylene microfilter having a pore size of 0.05 μm, so that the resist underlayer film forming composition solution used in the lithography process using a multilayer film is used. Was prepared.

Comparative Example 1
To a mixture of 1 g of phenol novolak resin (weight average molecular weight 15000) represented by the following formula (5-4), 1 g of bisphenol fluorenediglycidyl ether represented by the following formula (5-5), and 0.06 g of triphenylphosphine, 39.14 g of cyclohexanone was added and dissolved to obtain a solution. Thereafter, the solution was filtered using a polyethylene microfilter having a pore size of 0.10 μm, and further filtered using a polyethylene microfilter having a pore size of 0.05 μm to prepare a resist underlayer film forming composition solution used for the lithography process.

Comparative Example 2
To 5 g of the fluorene resin represented by the formula (5-3) obtained in Synthesis Example 3, 0.015 g of Megafac R-30 (trade name, manufactured by Dainippon Ink & Chemicals, Inc.) as a surfactant was mixed. A solution was prepared by dissolving in 58 g of propylene glycol monomethyl ether acetate. Thereafter, the solution is filtered using a polyethylene microfilter having a pore size of 0.10 μm, and further filtered using a polyethylene microfilter having a pore size of 0.05 μm, so that the resist underlayer film forming composition solution used in the lithography process using a multilayer film is used. Was prepared.

(Measurement of optical parameters)
The resist underlayer film forming compositions prepared in Examples 1 to 4 and Comparative Example 1 or 2 were each applied onto a silicon wafer using a spinner. Heating was performed at 240 ° C. for 1 minute on a hot plate to form a resist underlayer film (film thickness: 0.25 μm). Using a spectroscopic ellipsometer, the refractive index (n value) and optical absorption coefficient (k value, also called attenuation coefficient) of these resist underlayer films at a wavelength of 248 nm and a wavelength of 193 nm were measured. The results are shown in Table 1.

(Elution test for photoresist solvent)
The resist underlayer film forming compositions prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were each applied onto a silicon wafer using a spinner. Heating was performed at 240 ° C. for 1 minute on a hot plate to form a resist underlayer film (film thickness: 0.25 μm). This resist underlayer film was immersed in ethyl lactate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and cyclohexanone, which are solvents used for the resist forming composition. As a result, all resist underlayer films were insoluble in the solvent.

(Measurement of dry etching rate)
The following etchers and etching gases were used to measure the dry etching rate.
ES401 (Nippon Scientific): CF ₄
The resist underlayer film forming compositions prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were each applied onto a silicon wafer using a spinner. Heating was performed at 240 ° C. for 1 minute on a hot plate to form a resist underlayer film (film thickness: 0.25 μm). The dry etching rate was measured using CF ₄ gas as the etching gas.

Moreover, the resist underlayer film forming composition prepared in Example 1 and Comparative Example 2 was applied onto a silicon wafer using a spinner. Heating was performed at 400 ° C. for 2 minutes on a hot plate to form a resist underlayer film (film thickness: 0.25 μm). The dry etching rate was measured using CF ₄ gas as the etching gas.

Similarly, a phenol novolac resin solution was formed on a silicon wafer using a spinner. The film was heated on a hot plate at 205 ° C. for 1 minute to form a coating film (film thickness: 0.25 μm). The dry etching rate was measured using CF ₄ gas as an etching gas, and the dry etching rates of the resist underlayer films of Examples 1 to 4 and Comparative Examples 1 and 2 were compared. The results are shown in Table 2.

The speed ratio (1) is a dry etching speed ratio of (resist underlayer film after heating at 240 ° C. for 1 minute) / (phenol novolac resin film after heating at 205 ° C. for 1 minute).
The speed ratio (2) is a dry etching speed ratio of (resist underlayer film after heating at 400 ° C. for 2 minutes) / (phenol novolak resin film after heating at 205 ° C. for 1 minute).

(Heat resistance test of membrane)
The resist underlayer film forming compositions prepared in Examples 1 to 4 and Comparative Example 2 were applied onto a silicon wafer using a spinner. Heating was performed at 240 ° C. for 1 minute or 400 ° C. for 2 minutes on a hot plate to form a resist underlayer film (film thickness 0.25 μm). The obtained film was heated from room temperature (about 20 ° C.) at a rate of 10 ° C. per minute and subjected to thermogravimetric analysis in the atmosphere, and the temperature at which the mass decreased by 5 percent was measured. The results are shown in Table 3.

From the above results, the resist underlayer film used in the lithography process by the multilayer film of the present invention is different from the conventional high etch rate antireflection film, and the selectivity ratio of the dry etching rate close to the photoresist or small compared to the photoresist, It is possible to provide a resist underlayer film that has a lower dry etching rate selection ratio than a semiconductor substrate and can also have an effect as an antireflection film.
Moreover, since it does not melt | dissolve with respect to the solvent used for a resist composition, the resist underlayer film forming composition which forms the resist underlayer film which does not intermix with a resist layer can be provided.
Moreover, since the resist lower layer film of the present invention has a high 5% mass reduction temperature, it was found that the resist lower layer film has heat resistance capable of forming a hard mask on the upper layer by vapor deposition.

The polymers used in the present invention have high heat resistance, and the resist underlayer film forming composition using these polymers has heat stability even in the step of forming a hard mask by vapor deposition on the upper layer in a multilayer lithography process.

Claims

Following formula (1):

(Wherein R 1 and R 2 are substituents on the fluorene ring, and R 3 , R 4 , OR 5 , OR 6 are substituents on the naphthalene ring. R 1 , R 2 , R 3 , and R 4 represents an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, a halogen group, a nitro group, or an amino group, and R 5 and R 6 represent a hydrogen atom and 1 carbon atom, respectively. Represents an alkyl group of 10 to 10 or glycidyl group, Ar represents an arylene group of 6 to 20 carbon atoms, n1 and n2 are each an integer of 0 to 4, and n3 is an integer of 0 to (6-n5) N4 is an integer from 0 to (6-n6), n5 and n6 are each an integer from 1 to 6, n3 + n5 is an integer from 1 to 6, and n4 + n6 is an integer from 1 to 6 A polymer containing a repeating unit structure represented by: A resist underlayer film forming composition comprising
2. The resist underlayer film forming composition according to claim 1, wherein Ar in the formula (1) represents a substituted or unsubstituted phenylene group, naphthylene group, biphenylene group, anthrylene group, or pyrene group.
Furthermore, the resist underlayer film forming composition of Claim 1 or Claim 2 containing a crosslinking agent.
The resist underlayer film forming composition according to claim 3, wherein the crosslinking agent is a compound having an aromatic ring.
The cross-linking agent is a compound represented by the following formula (2) or a polymer or oligomer having a repeating unit structure represented by the following formula (3):

(In the formula (2), R 7 and R 8 each represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms, n7 is an integer of 1 to 4, n8 is an integer of 1 to (5-n7), and n7 + n8 is an integer of 2 to 5. In formula (3), R 9 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R 10 Represents an alkyl group having 1 to 10 carbon atoms, n9 is an integer of 1 to 4, n10 is an integer of 0 to (4-n9), and n9 + n10 is an integer of 1 to 4. Oligomers and polymers The number m of repeating unit structures is from 2 to 100.) The resist underlayer film forming composition according to claim 3.
The resist underlayer film forming composition according to any one of claims 1 to 5, further comprising an acid or an acid generator.
A resist underlayer film obtained by applying the resist underlayer film forming composition according to claim 1 onto a semiconductor substrate and baking the composition.
A method for forming a resist pattern, which is used for manufacturing a semiconductor, comprising a step of applying the resist underlayer film forming composition according to any one of claims 1 to 6 on a semiconductor substrate and baking the composition to form an underlayer film. .
A step of forming an underlayer film comprising the resist underlayer film forming composition according to any one of claims 1 to 6 on a semiconductor substrate, a step of forming a resist film on the underlayer film, A method of manufacturing a semiconductor device, comprising: a step of forming a resist pattern by light and electron beam irradiation and development; a step of etching the lower layer film with the resist pattern; and a step of processing a semiconductor substrate with the patterned lower layer film .
A step of forming an underlayer film comprising the resist underlayer film forming composition according to any one of claims 1 to 6 on a semiconductor substrate, a step of forming a hard mask on the underlayer film, and further on the hard mask Forming a resist film on the resist film, forming a resist pattern on the resist film by light and electron beam irradiation and development, etching the hard mask with the resist pattern, and forming the lower layer with the patterned hard mask. A method for manufacturing a semiconductor device, comprising: a step of etching a film; and a step of processing a semiconductor substrate with the patterned underlayer film.