WO2012169580A1

WO2012169580A1 - Block copolymer and resist underlayer film-forming composition

Info

Publication number: WO2012169580A1
Application number: PCT/JP2012/064668
Authority: WO
Inventors: 坂本　力丸; 邦慶何
Original assignee: 日産化学工業株式会社
Priority date: 2011-06-10
Filing date: 2012-06-07
Publication date: 2012-12-13
Also published as: TWI540165B; TW201302902A; JPWO2012169580A1

Abstract

[Problem] To provide a novel block copolymer, a method for producing the same, and a lithographic resist underlayer film-forming composition using the block copolymer. [Solution] A block copolymer having a structure represented by formula (1), where P and Q each independently represent a divalent organic group between two carbon atoms; s, t, and u each independently represent an integer 10 or higher; the two R₁s each independently represent a hydrogen atom or methyl group; the two R₂s each independently represent a hydrogen atom, phenyl group, benzyl group, naphthyl group, anthracenyl group, C_1-13 alkyl group, or a group including a lactone ring, at least one hydrogen atom of the phenyl group, naphthyl group, anthracenyl group, or alkyl group being optionally substituted by a hydroxyl group, C_1-13 alkoxy group, or halogen atom; and the two X's each independently represent an ester bond, an amide bond, or a single bond.

Description

Block copolymer and resist underlayer film forming composition

The present invention relates to a novel block copolymer, a method for producing the same, and a resist underlayer film forming composition for lithography using the block copolymer.

Conventionally, fine processing by lithography using a resist composition has been performed in the manufacture of semiconductor devices. The microfabrication forms a thin film of a photoresist composition on a semiconductor substrate such as a silicon wafer, and irradiates with an actinic ray such as ultraviolet rays through a mask pattern on which a device pattern is drawn, and develops it. This is a processing method for forming fine irregularities corresponding to the pattern on the substrate surface by etching the substrate using the obtained photoresist pattern as a protective film. In recent years, semiconductor devices have been highly integrated, and actinic rays used have been shortened from i-line (wavelength 365 nm) and KrF excimer laser (wavelength 248 nm) to ArF excimer laser (wavelength 193 nm). Along with this, the influence of diffuse reflection of active rays from the semiconductor substrate and standing waves has become a major problem. In order to solve this problem, a method of providing an antireflection film (Bottom Anti-Reflective Coating: BARC) between a resist and a semiconductor substrate has been widely studied. The antireflection film is also referred to as a resist underlayer film. As a component of the composition for forming such an antireflection film (resist underlayer film), many studies have been made on polymers having a light absorbing group. For example, Patent Document 1 discloses an antireflection film-forming composition containing an acrylic polymer. Patent Document 2 discloses a composition obtained by a polymerization reaction of a bifunctional diglycidyl ester compound and 2,4-dihydroxybenzoic acid. A resist underlayer film forming composition containing a linear polymer is disclosed.

On the other hand, in lithography using EUV (abbreviation for extreme ultraviolet light, wavelength 13.5 nm) exposure, which is a further fine processing technique, there is no reflection from the substrate, but the roughness of the resist pattern side wall becomes a problem as the pattern becomes finer. Many studies have been made on a resist underlayer film for forming a highly rectangular resist pattern. As a material for forming a resist underlayer film for exposure to high energy rays such as EUV and electron beam, a resist underlayer film forming composition with reduced outgas generation is disclosed (Patent Document 3).

International Publication No. 2003/017002 International Publication No. 2009/057458 International Publication No. 2010/061774

The characteristics required for the resist underlayer film described above include, for example, insolubility in a resist solvent, and diffusion of low-molecular substances from the resist underlayer film to the upper layer resist at the time of coating or subsequent baking. In addition, it is possible to form a resist pattern having a shape without tailing, excellent adhesion to the resist, and a higher dry etching rate than the resist.

The present invention is a block copolymer used for a resist underlayer film forming composition that has high adhesion to a resist film and can form a good (rectangular shape) resist pattern even when the resist underlayer film is thin in response to the thinning of the resist. The object is to obtain a polymer. The resist underlayer film forming composition containing the block copolymer of the present invention is such that the formed resist underlayer film is insoluble in the solvent of the resist applied thereon, and the formed resist underlayer film and the resist film The condition is that there is no intermixing.

The first aspect of the present invention is:
It is a block copolymer having a structure represented by the following formula (1).

[Wherein, P and Q each independently represent a divalent organic group, s, t and u each independently represent an integer of 10 or more, and two R _{1 s} each independently represent a hydrogen atom or a methyl group. Two R _{2 s} each independently represent a hydrogen atom, a phenyl group, a benzyl group, a naphthyl group, an anthracenyl group, an alkyl group having 1 to 13 carbon atoms, or a group containing a lactone ring, and the phenyl group, naphthyl group, The anthracenyl group and the alkyl group may have at least one hydrogen atom substituted with a hydroxy group, an alkoxy group having 1 to 13 carbon atoms, or a halogen atom (for example, F, Cl, Br, I). Each independently represents an ester bond, an amide bond or a single bond. ]

The second aspect of the present invention is:
4,4′-azobis (4-cyanovaleric acid), the following formula (12) or formula (13), and formula (14):

{In the formula, m and n each independently represent 0 or 1, P ₁ and Q each independently represent a divalent organic group, and Z ₂ represents the following formula (8), formula (9) or formula (10 ):

(Wherein R ₆ represents an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms, and R ₇ and R ₈ each independently represents a hydrogen atom or an alkyl having 1 to 6 carbon atoms. Group, an alkenyl group having 2 to 6 carbon atoms or a phenyl group.)
In the case where Z ₂ is a divalent group represented by the formula (8) or the formula (10), one of the formula (8) and the formula (10) The carbonyl group constituting the part is bonded to the nitrogen atom of the formula (13). }
And a block copolymer production method according to the first aspect of the present invention in which at least one radical polymerizable monomer is polymerized in the same reaction system in the presence of a catalyst.

The third aspect of the present invention is:
It is the resist underlayer film forming composition for lithography containing the block copolymer of the 1st aspect of this invention, a crosslinking agent, and a solvent.

By using the block copolymer of the present invention in a resist underlayer film forming composition, it has excellent adhesion with a resist film provided on the upper layer of the resist underlayer film, and has a good resist pattern without pattern peeling or pattern disappearance. Can be formed. Furthermore, the resist underlayer film-forming composition containing the block copolymer of the present invention has better coatability on the substrate than the resist underlayer film-forming composition blended with two kinds of polymers, and the resulting film High uniformity is expected. When a film is prepared from a composition in which two kinds of polymers are blended, a polymer having a low surface energy is segregated to the film surface, so when the composition is applied onto a substrate having a step (unevenness), There is a difference in film properties between the upper part (convex part) and the lower part (concave part) of the step (unevenness). That is, the upper part (convex part) of the level difference (unevenness) is thinner than the lower part (concave part), so that the amount of the polymer component that segregates on the surface may be reduced. On the other hand, even when polymers having different surface energies are used, it is possible to obtain a constant film composition without depending on the film thickness by using a block copolymer chemically bonded to each other.

[polymer]
The block copolymer of the present invention has a structure represented by the above formula (1) in which two types of polymer (or oligomer) structures are linked via a linking group represented by the following formula (15). Here, examples of the two polymer structures include polymers obtained by polymerizing radically polymerizable monomers (for example, acrylic polymers and styrene polymers) and polyesters. In the formula (1), s, t, and u represent the number of repetitions of the polymer structure, and the upper limit is not particularly limited, but is, for example, 10,000. The terminal of the block copolymer of the present invention is presumed to be a hydrogen atom.

In the formula (1), Q representing a divalent organic group is, for example, the following formula (2):

{In the formula, Z ₁ is the following formula (3), formula (4) or formula (5):

(Wherein R ₃ represents an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms, and R ₄ and R ₅ each independently represents a hydrogen atom or an alkyl having 1 to 6 carbon atoms. Group, an alkenyl group having 2 to 6 carbon atoms or a phenyl group.)
When Z ₁ is a divalent group represented by the formula (3) or the formula (5), one of the formula (3) and the formula (5) The carbonyl group constituting the part is bonded to the nitrogen atom of the formula (2). }
It is represented by

In the formula (1), Q representing a divalent organic group is replaced with the following formula (6) instead of the formula (2).

(Wherein j and k each independently represent 0 or 1, Q ₁ is a divalent group having an alkylene group having 1 to 10 carbon atoms and an alicyclic hydrocarbon ring having 3 to 10 carbon atoms in the main chain. A phenylene group, a naphthylene group or an anthrylene group.)
It may be represented by

In the formula (1), as in Q, P representing a divalent organic group is, for example, the following formula (7):

{In the formula, Z ₂ is the following formula (8), formula (9) or formula (10):

(Wherein R ₆ represents an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms, and R ₇ and R ₈ each independently represents a hydrogen atom or an alkyl having 1 to 6 carbon atoms. Group, an alkenyl group having 2 to 6 carbon atoms or a phenyl group.)
In the case where Z ₂ is a divalent group represented by the formula (8) or the formula (10), one of the formula (8) and the formula (10) The carbonyl group constituting the part is bonded to the nitrogen atom of the formula (7). }
It is represented by

In the formula (1), P representing a divalent organic group is replaced by the following formula (11) instead of the formula (7).

(In the formula, m and n each independently represent 0 or 1, and P ₁ represents a divalent organic group.)
It may be represented by
P ₁ is, for example, an alkylene group having 1 to 10 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, an alkylene group having 2 to 10 carbon atoms having a sulfide structure or a disulfide structure, or 3 to 10 carbon atoms. Represents a divalent group having a main chain of an alicyclic hydrocarbon ring, a phenylene group, a naphthylene group, or an anthrylene group, wherein the phenylene group, the naphthylene group, and the anthrylene group have at least one hydrogen atom substituted with a hydroxy group. May be.

Further, in the above formula (1), the ester bond and amide bond represented by X are represented by —C (═O) —O— and —C (═O) —NH—, respectively, and constitute a part of them. The carbonyl group to be bonded is bonded to the main chain having the structure represented by the formula (1). When X represents a single bond, R ₂ in the formula (1) is directly bonded to the main chain of the structure represented by the formula (1).

As described above, the block copolymer of the present invention includes 4,4′-azobis (4-cyanovaleric acid), a compound represented by the above formula (12) or formula (13), and formula (14), In addition, it can be obtained by polymerizing at least one radical polymerizable monomer in the same reaction system in the presence of a catalyst. The 4,4′-azobis (4-cyanovaleric acid) is suitably used in the present invention as a radical initiator having a carboxyl group that reacts with an epoxy group, and is used in the above-described formula (12) or formula ( An appropriate amount can be used from the range of 0.5 mol% to 10 mol%, for example, with respect to the total amount of the compounds represented by 13) and formula (14).

In formula (12), P ₁ representing a divalent organic group is, for example, an alkylene group having 1 to 10 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, a carbon number of 2 having a sulfide structure or a disulfide structure. Represents a divalent group having a main chain having an alicyclic hydrocarbon ring having 3 to 10 carbon atoms in the main chain, a phenylene group, a naphthylene group or an anthrylene group, and the phenylene group, naphthylene group and anthrylene group are At least one hydrogen atom may be substituted with a hydroxy group.

In the formula (14), Q representing a divalent organic group is, for example, the following formula (2):

(Wherein R ₃ represents an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms, and R ₄ and R ₅ each independently represents a hydrogen atom or an alkyl having 1 to 6 carbon atoms. Group, an alkenyl group having 2 to 6 carbon atoms or a phenyl group.)
It is represented by

In the formula (14), Q representing a divalent organic group is replaced with the following formula (6) instead of the formula (2).

Specific examples of the compounds represented by the formulas (12) and (13) are shown in the following formulas (12-1) to (12-21) and formulas (13-1) to (13-4). The compound represented by the formula (12) and the formula (13) is, for example, an appropriate amount from the range of 40 mol% to 49.5 mol% with respect to the compound represented by the formula (14) used in the polymerization reaction. Can be used.

Specific examples of the compound represented by the formula (14) are shown in the following formulas (14-1) to (14-10).

Examples of the radical polymerizable monomer include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, 2,2,2-trifluoroethyl methacrylate, 2-hydroxypropyl methacrylate, γ-butyrolactone methacrylate, benzyl methacrylate, p -T-butoxystyrene, p-acetoxystyrene, p-ethoxyethyl styrene, styrene, anthracene methyl methacrylate, phenyl methacrylate, p-hydroxyphenyl methacrylate, naphthyl methacrylate, adamantyl methacrylate, hydroxyadamantyl methacrylate, norbornene lactone methacrylate, ethyladamantyl methacrylate, Methyl acrylate, ethyl acrylate , Isopropyl acrylate, cyclohexyl acrylate, 2,2,2-trifluoroethyl acrylate, 2-hydroxypropyl acrylate, γ-butyrolactone acrylate, benzyl acrylate, anthracene methyl acrylate, phenyl acrylate, p-hydroxyphenyl acrylate, naphthyl acrylate, Examples thereof include acrylic compounds such as vinyl acetate and vinyl benzoate, methacrylic compounds, and compounds having a vinyl group. From the examples of these radical polymerizable monomers, one or more are selected, and the total amount of the compounds represented by formula (12) or formula (13) and formula (14) used in the polymerization reaction is used. For example, an appropriate amount can be used from the range of 3% by mass to 200% by mass.

The catalyst used for the polymerization reaction is to activate the epoxy group of the compound represented by the formula (14), and for example, a quaternary phosphonium salt such as ethyltriphenylphosphonium bromide, benzyltriethylammonium chloride. And quaternary ammonium salts such as The catalyst can be used in an appropriate amount, for example, from 1.0 mol% to 10 mol% with respect to the compound represented by the formula (14) used. Optimum conditions can be selected for the temperature and time for the polymerization reaction, for example, in the range of 60 ° C. to 140 ° C. and 1 hour to 48 hours.

The content ratio of the block copolymer to the resist underlayer film forming composition for lithography containing the block copolymer of the present invention can be selected from a range of 0.01% by mass to 30.0% by mass, for example. Moreover, if the component except the solvent mentioned later is defined as solid content, the solid content contains the block copolymer, a crosslinking agent, and the additive mentioned later added as needed.

[Crosslinking agent]
Although there is no restriction | limiting in particular as a crosslinking agent contained in the resist underlayer film forming composition for lithography containing the block copolymer of this invention, The crosslinkable compound which has at least 2 crosslink formation substituent is used preferably. Examples of the crosslinking agent include a melamine compound having a crosslinking forming substituent such as a methylol group and a methoxymethyl group, a substituted urea compound, and a polymer compound containing an epoxy group. Preferably, it is a nitrogen-containing compound having 2 to 4 nitrogen atoms substituted with a methylol group or an alkoxymethyl group. The content of the cross-linking agent can be selected, for example, from a range of 5% by mass to 40% by mass with respect to the content of the block copolymer.

[Crosslinking catalyst]
In order to promote the crosslinking reaction, the resist underlayer film forming composition for lithography containing the block copolymer of the present invention may further contain a crosslinking catalyst. Examples of such a crosslinking catalyst include p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium-p-toluenesulfonate, salicylic acid, camphorsulfonic acid, 5-sulfosalicylic acid, 4-chlorobenzenesulfonic acid, 4-hydroxybenzenesulfone. Acid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, citric acid, benzoic acid, hydroxybenzoic acid and other sulfonic acid compounds and carboxylic acid compounds can be used. These crosslinking catalysts can be used alone or in combination of two or more. When the crosslinking catalyst is used, the content of the crosslinking catalyst can be selected, for example, from a range of 1% by mass to 20% by mass with respect to the content of the crosslinking agent.

The solvent contained in the resist underlayer film forming composition for lithography containing the block copolymer of the present invention is not particularly limited as long as the block copolymer can be dissolved. Examples of such solvents include ethylene glycol monomethyl ether, propylene glycol monoethyl 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 monopropyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, γ-butyrolactone, N-methyl-2-pyrrolidone, ethyl 2-hydroxypropionate, 2 -Hydroxy-2-methyl Ethyl propionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, Examples include methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, and butyl lactate. These organic solvents are used alone or in combination of two or more. Of the above solvents, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, and cyclohexanone are preferred.

In the resist underlayer film forming composition for lithography containing the block copolymer of the present invention, various additives such as a surfactant may be further included as needed as long as the effects of the present invention are not impaired.

When the above surfactant is included, specific examples thereof include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, and polyoxyethylene. Polyoxyethylene alkylaryl ethers such as octylphenol ether and polyoxyethylene nonylphenol ether, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan Sorbitan fatty acid esters such as trioleate and sorbitan tristearate, polyoxyethylene sorbitan monolaur Nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tristearate, EFTOP [registered trademark] EF301, EF303, EF352 (Mitsubishi Materials Electronics Kasei Co., Ltd. (formerly Gemco) manufactured), MegaFac [registered trademark] F171, F173, R30 (manufactured by DIC Corporation) ), FLORARD FC430, FC431 (manufactured by Sumitomo 3M), Asahi Guard [registered trademark] AG710, Surflon [registered trademark] S-382, SC101, SC102, SC103, SC104, SC105, SC106 Fluorocarbon surfactant Asahi Glass Co., Ltd.) and the like, can be mentioned organosiloxane polymer KP341 manufactured by (Shin-). These surfactants may be added alone or in combination of two or more.

When the surfactant is used, the content of the surfactant can be selected from the range of 0.01% by mass to 5% by mass with respect to the content of the block copolymer, for example.

Hereinafter, the present invention will be described in detail with reference to synthesis examples and examples, but the present invention is not limited to the following description.

The weight average molecular weights shown in the following Synthesis Examples 1 to 8 are based on measurement results by gel permeation chromatography (hereinafter abbreviated as GPC in this specification). For measurement, a GPC device manufactured by Tosoh Corporation was used, and the measurement conditions were as follows.
GPC column: Shodex (registered trademark) and Asahipak (registered trademark) (Showa Denko KK)
Column temperature: 40 ° C
Solvent: N, N-dimethylformamide (DMF)
Flow rate: 0.6 mL / min Standard sample: Polystyrene (Tosoh Corporation)
Detector: RI

<Synthesis Example 1: (MADG-2, 4DHBA / MMA)>
Monoallyl diglycidyl isocyanuric acid (hereinafter abbreviated as MADG, manufactured by Shikoku Kasei Kogyo Co., Ltd.) 10.00 g, 2,4-dihydroxybenzoic acid (hereinafter abbreviated as 2,4DHBA) 5.29 g, ethyltriphenylphosphonium bromide 0 .67 g, 3.06 g of methyl methacrylate (hereinafter abbreviated as MMA) and 0.51 g of 4,4′-azobis (4-cyanovaleric acid) were dissolved in 65.85 g of propylene glycol monomethyl ether. The polymer was reacted for a time to obtain a polymer compound solution. When the GPC analysis of the high molecular compound in the obtained solution was performed, the weight average molecular weight was 10,300 in standard polystyrene conversion.

<Synthesis Example 2: (MADG-2, 4DHBA / TFEMA)>
10.00 g of monoallyl diglycidyl isocyanuric acid (manufactured by Shikoku Kasei Kogyo Co., Ltd.), 5.29 g of 2,4-dihydroxybenzoic acid, 0.67 g of ethyltriphenylphosphonium bromide, 2,2,2-trifluoroethyl methacrylate ( Hereinafter, 3.06 g of TFEMA) and 0.51 g of 4,4′-azobis (4-cyanovaleric acid) are dissolved in 65.85 g of propylene glycol monomethyl ether, followed by reaction at 100 ° C. for 12 hours to obtain a polymer compound. Solution was obtained. When the GPC analysis of the high molecular compound in the obtained solution was performed, the weight average molecular weight was 7,500 in standard polystyrene conversion.

<Synthesis Example 3: (MADG-2, 4DHBA / HPMA-GBLMA)>
10.00 g of monoallyl diglycidyl isocyanuric acid (manufactured by Shikoku Chemicals Co., Ltd.), 5.29 g of 2,4-dihydroxybenzoic acid, 0.67 g of ethyltriphenylphosphonium bromide, 2-hydroxypropyl methacrylate (hereinafter abbreviated as HPMA) ) 1.53 g, 1.53 g of γ-butyrolactone methacrylate (hereinafter abbreviated as GBLMA) and 0.51 g of 4,4′-azobis (4-cyanovaleric acid) were dissolved in 65.85 g of propylene glycol monomethyl ether, Reaction was performed at 100 ° C. for 12 hours to obtain a polymer solution. When the GPC analysis of the high molecular compound in the obtained solution was performed, the weight average molecular weight was 9,100 in standard polystyrene conversion.

<Synthesis Example 4: (MADG-2, 4DHBA / BMA-HPMA-GBLMA)>
10.00 g of monoallyl diglycidyl isocyanuric acid (manufactured by Shikoku Kasei Kogyo Co., Ltd.), 5.29 g of 2,4-dihydroxybenzoic acid, 0.67 g of ethyltriphenylphosphonium bromide, benzyl methacrylate (hereinafter abbreviated as BMA) 02 g, 1.02 g of 2-hydroxypropyl methacrylate, 1.02 g of γ-butyrolactone methacrylate and 0.51 g of 4,4′-azobis (4-cyanovaleric acid) were dissolved in 65.85 g of propylene glycol monomethyl ether. The polymer compound solution was obtained by reacting at 12 ° C. for 12 hours. When the GPC analysis of the high molecular compound in the obtained solution was performed, the weight average molecular weight was 10,300 in standard polystyrene conversion.

<Synthesis Example 5: (MADG-2, 4DHBA / BMA-HPMA-GBLMA)>
10.00 g monoallyl diglycidyl isocyanuric acid (manufactured by Shikoku Kasei Kogyo Co., Ltd.), 5.29 g 2,4-dihydroxybenzoic acid, 0.67 g ethyltriphenylphosphonium bromide, 2.04 g benzyl methacrylate, 2-hydroxypropyl methacrylate 2.04 g, 2.04 g of γ-butyrolactone methacrylate and 0.51 g of 4,4′-azobis (4-cyanovaleric acid) are dissolved in 65.85 g of propylene glycol monomethyl ether, followed by reaction at 100 ° C. for 12 hours. A solution of molecular compounds was obtained. When the GPC analysis of the high molecular compound in the obtained solution was performed, the weight average molecular weight was 10,300 in standard polystyrene conversion.

<Synthesis Example 6: (MMDG-FA / PTBS-HPMA-GBLMA)>
Monomethyldiglycidyl isocyanuric acid (hereinafter abbreviated as MMDG, manufactured by Shikoku Kasei Kogyo Co., Ltd.) 8.00 g, fumaric acid (hereinafter abbreviated as FA) 3.49 g, ethyltriphenylphosphonium bromide 0.59 g, pt- 0.69 g of butoxystyrene (hereinafter abbreviated as PTBS), 0.92 g of 2-hydroxypropyl methacrylate, 0.69 g of γ-butyrolactone methacrylate and 0.44 g of 4,4′-azobis (4-cyanovaleric acid) were mixed with propylene glycol monomethyl. After dissolving in 50.10 g of ether and reacting for 12 hours at 100 ° C., a polymer compound solution was obtained, and GPC analysis of the polymer compound in the obtained solution was performed. The molecular weight was 14,300.

<Synthesis Example 7: (MMDG-FA / PTBS-HPMA-GBLMA)>
Monomethyldiglycidyl isocyanuric acid (manufactured by Shikoku Kasei Kogyo Co., Ltd.) 8.00 g, fumaric acid 3.49 g, and ethyltriphenylphosphonium bromide 0.59 g, pt-butoxystyrene 1.38 g, 2-hydroxypropyl methacrylate 1 .84 g, 1.38 g of γ-butyrolactone methacrylate and 0.44 g of 4,4′-azobis (4-cyanovaleric acid) were dissolved in 50.10 g of propylene glycol monomethyl ether, and reacted at 100 ° C. for 12 hours to obtain a polymer. A solution of the compound was obtained. When the GPC analysis of the high molecular compound in the obtained solution was performed, the weight average molecular weight was 29,600 in standard polystyrene conversion.

<Synthesis Example 8: (MADG-2, 4DHBA)>
15.00 g of monoallyl diglycidyl isocyanuric acid (manufactured by Shikoku Kasei Kogyo Co., Ltd.), 8.46 g of 2,4-dihydroxybenzoic acid, and 1.02 g of ethyltriphenylphosphonium bromide were dissolved in 57.12 g of propylene glycol monomethyl ether. And then reacted at 130 ° C. for 24 hours to obtain a polymer solution. When the GPC analysis of the high molecular compound in the obtained solution was performed, the weight average molecular weight was 9,200 in standard polystyrene conversion.

<Example 1>
To 10 g of the solution containing 2 g of the polymer obtained in Synthesis Example 1, 0.5 g of tetramethoxymethylglycoluril (manufactured by Nippon Cytec Industries, Ltd., trade name: POWDERLINK [registered trademark] 1174) and pyridinium-p-toluene 0.05 g of sulfonate was mixed and dissolved in 35.4 g of propylene glycol monomethyl ether and 18.6 g of propylene glycol monomethyl ether acetate to obtain a solution. Then, it filtered using the polyethylene micro filter with the hole diameter of 0.10 micrometer, and also filtered using the polyethylene micro filter with the hole diameter of 0.05 micrometer, and prepared the resist underlayer film forming composition.

<Example 2>
To 10 g of the solution containing 2 g of the polymer obtained in Synthesis Example 2, 0.5 g of tetramethoxymethylglycoluril (manufactured by Nippon Cytec Industries, Inc., trade name: POWDERLINK [registered trademark] 1174) and pyridinium-p-toluene 0.05 g of sulfonate was mixed and dissolved in 35.4 g of propylene glycol monomethyl ether and 18.6 g of propylene glycol monomethyl ether acetate to obtain a solution. Then, it filtered using the polyethylene micro filter with the hole diameter of 0.10 micrometer, and also filtered using the polyethylene micro filter with the hole diameter of 0.05 micrometer, and prepared the resist underlayer film forming composition.

<Example 3>
To 10 g of the solution containing 2 g of the polymer obtained in Synthesis Example 3, 0.5 g of tetramethoxymethylglycoluril (manufactured by Nippon Cytec Industries, Inc., trade name: POWDERLINK [registered trademark] 1174) and pyridinium-p-toluene 0.05 g of sulfonate was mixed and dissolved in 35.4 g of propylene glycol monomethyl ether and 18.6 g of propylene glycol monomethyl ether acetate to obtain a solution. Then, it filtered using the polyethylene micro filter with the hole diameter of 0.10 micrometer, and also filtered using the polyethylene micro filter with the hole diameter of 0.05 micrometer, and prepared the resist underlayer film forming composition.

<Example 4>
To 10 g of the solution containing 2 g of the polymer obtained in Synthesis Example 4, 0.5 g of tetramethoxymethylglycoluril (manufactured by Nippon Cytec Industries, Inc., trade name: POWDERLINK [registered trademark] 1174) and pyridinium-p-toluene 0.03 g of sulfonate was mixed and dissolved in 34.5 g of propylene glycol monomethyl ether and 18.2 g of propylene glycol monomethyl ether acetate to obtain a solution. Then, it filtered using the polyethylene micro filter with the hole diameter of 0.10 micrometer, and also filtered using the polyethylene micro filter with the hole diameter of 0.05 micrometer, and prepared the resist underlayer film forming composition.

<Example 5>
To 10 g of the solution containing 2 g of the polymer obtained in Synthesis Example 5, 0.5 g of tetramethoxymethylglycoluril (manufactured by Nippon Cytec Industries, Inc., trade name: POWDERLINK [registered trademark] 1174) and pyridinium-p-toluene 0.03 g of sulfonate was mixed and dissolved in 34.5 g of propylene glycol monomethyl ether and 18.2 g of propylene glycol monomethyl ether acetate to obtain a solution. Then, it filtered using the polyethylene micro filter with the hole diameter of 0.10 micrometer, and also filtered using the polyethylene micro filter with the hole diameter of 0.05 micrometer, and prepared the resist underlayer film forming composition.

<Example 6>
To 10 g of the solution containing 2 g of the polymer obtained in Synthesis Example 6, 0.5 g of tetramethoxymethylglycoluril (manufactured by Nippon Cytec Industries, Inc., trade name: POWDERLINK [registered trademark] 1174) and pyridinium-p-toluene 0.03 g of sulfonate was mixed and dissolved in 34.5 g of propylene glycol monomethyl ether and 18.2 g of propylene glycol monomethyl ether acetate to obtain a solution. Then, it filtered using the polyethylene micro filter with the hole diameter of 0.10 micrometer, and also filtered using the polyethylene micro filter with the hole diameter of 0.05 micrometer, and prepared the resist underlayer film forming composition.

<Example 7>
To 10 g of the solution containing 2 g of the polymer obtained in Synthesis Example 7, 0.5 g of tetramethoxymethyl glycoluril (manufactured by Nippon Cytec Industries, Ltd., trade name: POWDERLINK [registered trademark] 1174) and pyridinium-p-toluene 0.03 g of sulfonate was mixed and dissolved in 34.5 g of propylene glycol monomethyl ether and 18.2 g of propylene glycol monomethyl ether acetate to obtain a solution. Then, it filtered using the polyethylene micro filter with the hole diameter of 0.10 micrometer, and also filtered using the polyethylene micro filter with the hole diameter of 0.05 micrometer, and prepared the resist underlayer film forming composition.

<Comparative Example 1>
A copolymer represented by the following formula (16) is included as a polymer, and includes tetramethoxymethyl glycoluril (manufactured by Nippon Cytec Industries, Inc., trade name: POWDERLINK [registered trademark] 1174) and pyridinium-p-toluenesulfonate. A resist underlayer film forming composition was prepared.

<Comparative Example 2>
Polymethylmethacrylate (weight average molecular weight 30,000), 0.4 g, 1.6 g of the polymer obtained in Synthesis Example 8 above, tetramethoxymethylglycoluril (manufactured by Nippon Cytec Industries, Ltd., trade name: POWDERLINK [registered trademark] 1174) and pyridinium-p-toluenesulfonate, a resist underlayer film forming composition was prepared.

<Comparative Example 3>
0.4 g of poly-2,2,2-trifluoroethyl methacrylate (weight average molecular weight 30,000), 1.6 g of the polymer obtained in Synthesis Example 8, tetramethoxymethylglycoluril (manufactured by Nippon Cytec Industries, Ltd., A resist underlayer film forming composition containing trade name: POWDERLINK (registered trademark) 1174) and pyridinium-p-toluenesulfonate was prepared.

[Elution test in resist solvent]
The resist underlayer film forming composition prepared in Example 1 to Example 7 of the present invention was applied (spin coated) onto a silicon wafer using a spinner, and heated on a hot plate at 205 ° C. for 1 minute to form a resist. A lower layer film was formed. This resist underlayer film was immersed in propylene glycol monomethyl ether acetate, which is a solvent of the resist solution, and it was confirmed that there was almost no change in film thickness due to the solvent immersion. On the other hand, in Comparative Example 2 and Comparative Example 3, a change in film thickness due to solvent immersion was confirmed.

In Table 1, Comparative Example 2 and Comparative Example 3 in which the resist underlayer film formed from the resist underlayer film forming composition of Example 1 and Example 2 using the block copolymer of the present invention and two kinds of polymers were blended A comparison with a resist underlayer film formed from the resist underlayer film forming composition is described. Whether the solvent resistance is good or not is good when the difference in film thickness before and after the solvent treatment is 1.0 nm or less because it has sufficient solvent resistance as a resist underlayer film, and when it is 1.1 nm or more, the lithography performance is deteriorated. Therefore, the solvent resistance was regarded as poor.

The methacrylate polymer used in Comparative Example 2 and Comparative Example 3 does not have a functional group (such as a hydroxy group) that can react with a crosslinking agent. Since the block copolymer used in Example 1 and Example 2 has a methacrylate polymer chemically bonded to a polyester having a hydroxy group, the polyester site in the block copolymer is cross-linked so that the solvent resistance is improved. can get. On the other hand, in the case of the resist underlayer film formed from the resist underlayer film forming composition of Comparative Example 2 and Comparative Example 3 in which two kinds of polymers are blended, since the methacrylate polymer cannot undergo a crosslinking reaction, it is dissolved by solvent immersion. It is considered that the film thickness has changed. That is, in the block copolymer of the present invention, even if it has a methacrylate polymer portion that does not have solvent resistance, it can have solvent resistance in the resist underlayer film by further having a polyester portion having a crosslinking portion. It becomes.

[Intermixing test with resist]
The resist underlayer film forming compositions prepared in Examples 1 to 7 of the present invention were each applied onto a silicon wafer using a spinner, heated on a hot plate at 205 ° C. for 1 minute, and the resist underlayer film ( A film thickness of 0.10 μm) was formed.

A commercially available resist solution (manufactured by Dow Chemical Company, trade name: UV113) is applied to the upper layer of the resist underlayer film using a spinner, and the resist film is heated on a hot plate at 120 ° C. for 1 minute. Formed. After exposure using an exposure apparatus, post-exposure heating (PEB: Post Exposure Bake) was performed at 115 ° C. for 1.5 minutes. After developing and rinsing the resist film, the thickness of the remaining resist underlayer film is measured, and the resist underlayer film and the resist film obtained from the resist underlayer film forming compositions prepared in Examples 1 to 7 It was confirmed that no intermixing occurred.

[Measurement of dry etching rate]
The resist underlayer film forming composition prepared in Example 1 to Example 7 of the present invention and the resist underlayer film forming composition shown in Comparative Example 1 were respectively applied on a silicon wafer using a spinner, and then on a hot plate. Then, the resist underlayer film was formed by heating at 205 ° C. for 1 minute. Then, Japan Scientific Inc., using RIE system ES401, was measured dry etching rate under a condition of using CF ₄ as a dry etching gas.

A resist solution (manufactured by Sumitomo Chemical Co., Ltd., trade name: PAR710) was applied onto a silicon wafer using a spinner, and a resist film was formed by the same method as described above. The dry etching rate was measured using RIE system ES401 manufactured by Nippon Scientific Co., Ltd. under the condition using CF ₄ as the dry etching gas.

8 types of resist underlayer films obtained from the resist underlayer film forming compositions of Examples 1 to 7 and Comparative Example 1, and the dry etching rate of the resist film obtained from the resist solution manufactured by Sumitomo Chemical Co., Ltd. And compared. Table 2 shows the ratio of the dry etching rate of the resist underlayer film to the dry etching rate of the resist film (selection ratio of the dry etching rate).

[Optical parameter test]
The resist underlayer film forming composition prepared in Example 1 to Example 7 of the present invention and the resist underlayer film forming composition shown in Comparative Example 1 were applied on a silicon wafer using a spinner, respectively, and hot plate Above, it heated at 205 degreeC for 1 minute, and formed the resist underlayer film. Using the resulting spectroscopic ellipsometer (manufactured by JA Woollam, VUV-VASE VU-302), the refractive index (n value) and attenuation coefficient (k value) at a wavelength of 193 nm were obtained from the eight resist underlayer films obtained. It was measured. The measurement results are shown in Table 2.

The resist underlayer film obtained by using the resist underlayer film forming composition prepared in Example 1 to Example 7 of the present invention has a large dry etching rate selectivity with respect to the resist film. The selection ratio of the dry etching rate is larger than that. Therefore, the time required for removing the resist underlayer film by dry etching can be shortened. In addition, it is possible to suppress an undesirable phenomenon in which the thickness of the resist film on the resist underlayer film decreases as the resist underlayer film is removed by dry etching.

Claims

A block copolymer having a structure represented by the following formula (1).

(In the formula, P and Q each independently represent a divalent organic group, s, t and u each independently represent an integer of 10 or more, and two R 1 s each independently represent a hydrogen atom or a methyl group. Two R 2 s each independently represent a hydrogen atom, a phenyl group, a benzyl group, a naphthyl group, an anthracenyl group, an alkyl group having 1 to 13 carbon atoms, or a group containing a lactone ring, and the phenyl group, naphthyl group, In the anthracenyl group and the alkyl group, at least one hydrogen atom may be substituted with a hydroxy group, an alkoxy group having 1 to 13 carbon atoms, or a halogen atom, and two Xs are each independently an ester bond, an amide bond or a single bond. Represents a bond.)
The block copolymer according to claim 1, wherein the terminal is a hydrogen atom.
In the formula (1), Q is the following formula (2):

{In the formula, Z 1 is the following formula (3), formula (4) or formula (5):

Wherein R 3 represents an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms, and R 4 and R 5 are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Represents an alkenyl group having 2 to 6 carbon atoms or a phenyl group.)
When Z 1 is a divalent group represented by the formula (3) or the formula (5), one of the formula (3) and the formula (5) The carbonyl group constituting the part is bonded to the nitrogen atom of the formula (2). }
The block copolymer of Claim 1 or Claim 2 represented by these.
In the formula (1), Q is the following formula (6):

(Wherein j and k each independently represent 0 or 1, Q 1 is a divalent group having an alkylene group having 1 to 10 carbon atoms and an alicyclic hydrocarbon ring having 3 to 10 carbon atoms in the main chain. A phenylene group, a naphthylene group or an anthrylene group.)
The block copolymer of Claim 1 or Claim 2 represented by these.
In the formula (1), P represents the following formula (7):

{In the formula, Z 2 is the following formula (8), formula (9) or formula (10):

Wherein R 6 represents an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms, and R 7 and R 8 are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Represents an alkenyl group having 2 to 6 carbon atoms or a phenyl group.)
In the case where Z 2 is a divalent group represented by the formula (8) or the formula (10), one of the formula (8) and the formula (10) The carbonyl group constituting the part is bonded to the nitrogen atom of the formula (7). }
The block copolymer as described in any one of Claims 1 thru | or 4 represented by these.
In the formula (1), P represents the following formula (11):

(In the formula, m and n each independently represent 0 or 1, and P 1 represents a divalent organic group.)
The block copolymer as described in any one of Claims 1 thru | or 4 represented by these.
In the formula (11), P 1 is an alkylene group having 1 to 10 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, an alkylene group having 2 to 10 carbon atoms having a sulfide structure or a disulfide structure, and the number of carbon atoms. Represents a divalent group having 3 to 10 alicyclic hydrocarbon rings in the main chain, a phenylene group, a naphthylene group or an anthrylene group, wherein the phenylene group, the naphthylene group and the anthrylene group have at least one hydrogen atom as a hydroxy group The block copolymer according to claim 6, which may be substituted.
4,4′-azobis (4-cyanovaleric acid), the following formulas (13) and (14):

{In the formula, Q represents a divalent organic group, and Z 2 represents the following formula (8), formula (9) or formula (10):

(Wherein R 6 represents an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms, and R 7 and R 8 each independently represents a hydrogen atom or an alkyl having 1 to 6 carbon atoms. Group, an alkenyl group having 2 to 6 carbon atoms or a phenyl group.)
In the case where Z 2 is a divalent group represented by the formula (8) or the formula (10), one of the formula (8) and the formula (10) The carbonyl group constituting the part is bonded to the nitrogen atom of the formula (13). }
The method for producing a block copolymer according to claim 5, wherein the compound represented by the above formula and at least one radical polymerizable monomer are polymerized in the same reaction system in the presence of a catalyst.
4,4′-azobis (4-cyanovaleric acid), the following formulas (12) and (14):

{In the formula, m and n each independently represent 0 or 1, and P 1 and Q each independently represent a divalent organic group. )
The method for producing a block copolymer according to claim 6, wherein the compound represented by the formula (1) and at least one radical polymerizable monomer are polymerized in the same reaction system in the presence of a catalyst.
In the formula (12), P 1 represents an alkylene group having 1 to 10 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, an alkylene group having 2 to 10 carbon atoms having a sulfide structure or a disulfide structure, and the number of carbon atoms. Represents a divalent group having 3 to 10 alicyclic hydrocarbon rings in the main chain, a phenylene group, a naphthylene group or an anthrylene group, wherein the phenylene group, the naphthylene group and the anthrylene group have at least one hydrogen atom as a hydroxy group The manufacturing method of the block copolymer of Claim 9 which may be substituted.
In the formula (14), Q is the following formula (2):

{In the formula, Z 1 is the following formula (3), formula (4) or formula (5):

(Wherein R 3 represents an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms, and R 4 and R 5 each independently represents a hydrogen atom or an alkyl having 1 to 6 carbon atoms. Group, an alkenyl group having 2 to 6 carbon atoms or a phenyl group.)
When Z 1 is a divalent group represented by the formula (3) or the formula (5), one of the formula (3) and the formula (5) The carbonyl group constituting the part is bonded to the nitrogen atom of the formula (2). }
The manufacturing method of the block copolymer of Claim 8 or Claim 9 represented by these.
In the formula (14), Q is the following formula (6):

(Wherein j and k each independently represent 0 or 1, Q 1 is a divalent group having an alkylene group having 1 to 10 carbon atoms and an alicyclic hydrocarbon ring having 3 to 10 carbon atoms in the main chain. A phenylene group, a naphthylene group or an anthrylene group.)
The manufacturing method of the block copolymer of Claim 8 or Claim 9 represented by these.
The method for producing a block copolymer according to claim 8 or 9, wherein the radical polymerizable monomer is an acrylic compound, a methacrylic compound or a compound having a vinyl group.
A resist underlayer film forming composition for lithography comprising the block copolymer according to any one of claims 1 to 7, a crosslinking agent, and a solvent.