TW201241016A - Resist underlayer film forming composition and method for forming resist pattern by use of the composition - Google Patents

Abstract

[Problem] One purpose of the present invention is to obtain a composition for forming a resist underlayer film, which is useful for reduction of LER. Another purpose of the present invention is to obtain a composition for forming a resist underlayer film, which enables a resist pattern on the resist underlayer film to have a desired shape. [Solution] A composition for forming a resist underlayer film for lithography, which contains a polymer that has structural units represented by formula (1) and formula (2), a crosslinking agent and a solvent. (In the formulae, R1 and R2 each independently represents a hydrogen atom or a methyl group; L1 represents a single bond or a divalent linking group that has a linear or branched alkylene group having 1-13 carbon atoms; A represents an aromatic ring group that has at least one substituent including a hydroxy group; and D represents a linear or branched hydroxyalkyl group having 1-13 carbon atoms.)

Description

201241016 VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to a composition for forming a photo-lithography photoresist underlayer film suitable for forming a photoresist pattern having a desired shape, and using the same to form a photoresist A method of forming a photoresist pattern of a composition of an underlayer film. More specifically, in the photolithography step of manufacturing a semiconductor device, the composition of the photoresist underlayer film which can reduce the pattern sidewall roughness of the photoresist pattern can be reduced. [Prior Art] When a semiconductor device was previously manufactured, microfabrication was performed by using photolithography of a photoresist composition. The microfabrication is performed by irradiating an active film such as ultraviolet rays under a mask having a pattern of a drawing device on a semiconductor substrate such as a tantalum wafer, and then obtaining the film. The photoresist pattern is a processing method in which a protective film is etched on a substrate, and a fine unevenness corresponding to the above-described pattern is formed on the surface of the substrate. In recent years, with the high integration of semiconductor devices, the active light used is also a short-wavelength ArF excimer laser (wavelength) from the i-line (wavelength 3 65 nm), KrF excimer laser (wavelength 248 nm). 193nm). It is a big problem with the scattering of active light from the semiconductor substrate and the influence of the wave. In order to solve this problem, a method of providing a Bottom Anti-Reflective Coating (BAC) between a photoresist and a semiconductor substrate has been extensively reviewed. This anti-reflection film is also referred to as a photoresist underlayer film. In the antireflection film, an organic antireflection film formed of a polymer having a light absorbing group or the like has been examined for many times in terms of ease of use (for example, Patent Document 1). -5- 3 201241016 In the micro-machining method using EUV (abbreviation of extreme ultraviolet light, wavelength 13.5 nm) in microfabrication technology, although the exposure light is not reflected by the substrate, there is a photoresist pattern accompanied by pattern refinement. The problem of the roughness of the sidewall is such that the photoresist underlayer film having a higher rectangular shape is formed. The material for forming a photoresist film for high-energy line exposure for forming an EUV or an electron beam has been disclosed to reduce the composition of the underlayer film forming the photoresist by the occurrence of gas (Patent Document 2). However, Patent Document 2 does not describe the problem of roughness of the pattern side wall. Further, the above Patent Document 1 is also not described. CITATION LIST PATENT DOCUMENT PATENT DOCUMENT 1: JP-A-2000-1 8733 No. 1 Patent Document 2: International Publication No. 20 1 0/06 1 774 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION The above-mentioned photoresist underlayer film is required The characteristics are, for example, not blended in the photoresist (insoluble in the photoresist solvent), and the low molecular substance does not diffuse from the photoresist underlayer film to the upper layer photoresist during baking at the time of coating or subsequent, It can form a photoresist pattern with no shape such as drag and drop, has excellent adhesion with photoresist and has a faster dry etching speed than photoresist. It is also required to improve the characteristics of the depth of focus that can be augmented and to achieve high resolution characteristics. The depth of focus limit means that the width of the full depth field in the state where the photoresist pattern is put into practical use can be maintained when the focus shifts above or below the focus position relative to the optimum focus position at the time of exposure. That is, expanding the depth of focus limit can give the manufacturing engineering greater margin. -6- 201241016 The pattern line width formed by the lithography of the EUV exposure is 32 nm or less, and the requirements for the line end roughness of the pattern side wall (hereinafter referred to as LER in the present specification) are also severe. When the shape of the photoresist pattern formed is a drag shape or a shape in which the adjacent patterns are separated and connected in succession, the LER値 obtained from the top of the pattern is large, which affects the size control. Therefore, it is strongly required that the shape of the photoresist pattern be a rectangular shape with a small LER値. Further, most of the underlayer film for EUV exposure is a film having a film thickness of 20 nm or less. SUMMARY OF THE INVENTION An object of the present invention is to provide a film having a high adhesion to a photoresist film, and to form a good (rectangular shape) photoresist pattern even if the photoresist film is formed into a thin film corresponding to the photoresist film. The composition for reducing the underlying film of the photoresist of LER is reduced. Further, it is an object of the invention to provide a composition for a photoresist underlayer film having a desired shape on a photoresist pattern formed on a photoresist underlayer film. The composition of the present invention has a condition that the formed underlayer film of the photoresist is insoluble in the photoresist coated thereon, and the formed photoresist underlayer film and the photoresist film are not blended. The first aspect of the present invention relates to a composition for forming a photolithography underlayer film comprising a polymer having a structural unit represented by the following formulas (1) and (2), a crosslinking agent, and a solvent. . [Chemical 1]

(I) (2) -7- 201241016 (wherein 1 and R2 each independently represent a hydrogen atom or a methyl group, !^ represents a single bond' or has a linear or branched carbon number of 1 to 13 The 2-valent bond group 'A' of the alkylene group means an aromatic ring group having at least one substituent having a hydroxyl group 'D represents a linear or branched hydroxyalkyl group having 1 to 13 carbon atoms). In the above polymer, the number of repetitions of the structural unit represented by the above formulas (1) and (2) is, for example, 10 to 10,000. The polymer may be a copolymer having a structural unit represented by the following formula (3) in addition to the structural unit represented by the above formulas (1) and (2), [Chemical 2]

0) (wherein r3 represents a hydrogen atom or a methyl group, l2 represents a single bond or a linear or branched alkyl group having 1 to 13 carbon atoms, and E represents a group containing a lactone ring or contains adamantane The base of the ring). When the single bond is represented by the formula (1), the aromatic ring group represented by the above A is directly bonded to an oxygen atom, and when L2 of the formula (3) represents a single bond, the lactone ring-containing group or the content represented by the above E is contained. The base of the adamantane ring is directly bonded to the oxygen atom. The aforementioned lactone ring and adamantane ring may have a substituent or an unsubstituted. The lactone ring described above may form part of a bicyclic or polycyclic (e.g., tricyclic) ring or may be bonded to its -8 - 201241016. Further, the above-mentioned divalent bond group is not limited to a linear or branched alkyl group having 1 to 13 carbon atoms, and may be, for example, the alkyl group and the -C(=0)-0- group, -0. a combination of -C(=0)- or a -Ο- group which may have a hydroxyl group of a substituent. According to a second aspect of the present invention, there is provided a method of applying a composition for forming a photolithography underlayer film of the present invention onto a semiconductor substrate and baking the photoresist underlayer film, and forming the photoresist underlayer film. a step of forming a photoresist film, a step of exposing the semiconductor substrate on which the photoresist underlayer film and the photoresist film are exposed, and a photoresist pattern of the step of developing the photoresist film by the developing solution after the exposure The method of formation. The foregoing exposure can be carried out, for example, using extreme ultraviolet rays (EUV), but is not limited to EUV, and KrF excimer laser, ArF excimer laser or electron beam can also be used. Advantageous Effects of Invention The composition for forming a photoresist film for photolithography according to the present invention is characterized in that the side chain end of the polymer contained in the composition for forming the photoresist underlayer film is combined with an aromatic ring group having a hydroxyl group of a substituent. The composition (for example, hydroxyphenyl) further contains a composition of the polymer, a crosslinking agent and a solvent. According to this configuration, the photoresist underlayer film has excellent adhesion to the photoresist film provided thereon, and the formed pattern does not peel off and the pattern does not disappear. Further, the composition for forming a photoresist underlayer film for photolithography of the present invention can provide a photoresist pattern underlayer film having a good shape in which the upper layer can be formed with almost no drag shape at the bottom and excellent in size controllability. -9- 201241016 Further, the photoresist underlayer film formed by the composition for forming a photoresist film for photolithography of the present invention has a high sensitivity and a high resolution with respect to a high energy line, particularly EUV, and can be made smaller in LER. Light resistance pattern. BEST MODE FOR CARRYING OUT THE INVENTION [Polymer] The polymer contained in the composition for forming a photoresist film for photolithography of the present invention is represented by the above formulas (1) and (2) containing a necessary structural unit. Construction unit. The structural unit represented by the above formula (1) is a light absorbing portion for adjusting the optical parameters (η値 (refractive index) and k値 (attenuation coefficient or absorption coefficient)) of the formed underlying photoresist film, and by The crosslinking agent is reacted to give a portion having a higher crosslinking density, and the hydroxyl group of the substituent of the aromatic ring group represented by A in the formula has an acidic unit function, thereby exhibiting a drag-free photoresist pattern. The part of the shape effect. The structural unit represented by the formula (2) is a portion which reacts with a crosslinking agent to form a photoresist-resistant underlayer film having solvent resistance. The aromatic ring of the above aromatic ring group is, for example, a benzene ring, a naphthalene ring or an anthracene ring. The monomer which forms the structural unit represented by the above formula (1), such as P-hydroxyphenyl (meth) acrylate or P. hydroxybenzyl (meth) acrylate, forms the structure represented by the above formula (2) Monomers such as monomers having at least one hydroxyl group, such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate Ester, 2,3. dihydroxypropyl (meth) acrylate. -10-201241016 Among the monomers forming the structural unit represented by the above formula (3), a compound represented by the following structural formula is preferable. [Chemical 3]

In the above formula, Ra represents a hydrogen atom or a methyl group, and Rb each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms, 11. The linear or branched alkyl group having 1 to 5 carbon atoms is represented by a linear or branched alkyl group having 1 to 5 carbon atoms. More specifically, the following monomers having a group containing a lactone ring or a group containing an adamantane ring are exemplified below.

CH, SH2=sCH CM2=C ch3=ch 0=1 0=^ 0=%

-11 - 201241016 [化5]

[Chemical 6]

The polymer used for forming the composition of the photoresist underlayer film of the present invention is particularly preferably a copolymer comprising a structural unit represented by the following formula (1-1), formula (2-1) and formula (3-1). Things. -12- 201241016 [化7]

(Μ) (Μ) (3-1) The polymer used in the composition for forming a photoresist film for photolithography of the present invention has the above formula (1), formula (2) and, if necessary, When the structural unit represented by the formula (3) is 1% by mass in total, the ratio of the structural unit represented by the formula (1) is 1% by mass to 80% by mass (in terms of the addition ratio of the monomer), preferably 5 The mass% to 50% by mass, more preferably 20% by mass to 40% by mass. Further, the ratio of the structural unit represented by the formula (2) is from 1% by mass to 80% by mass (in terms of the addition ratio of the monomer), preferably from 5% by mass to 50% by mass, more preferably from 20% by mass to 40% by mass. The ratio of the structural unit represented by the formula (3) is from 1% by mass to 60% by mass (calculated as the ratio of addition of the monomers), preferably from 5% by mass to 50% by mass, more preferably from 20% by mass to 40% by mass. The polymer used in the composition for forming the photoresist film for photolithography of the present invention may be any of a random copolymer, a block copolymer, an interactive copolymer, and a graft copolymer. The resin forming the photoresist underlayer film of the present invention can be synthesized by a method such as radical polymerization, anionic polymerization, cationic polymerization or the like. The polymerization method may be various methods such as solution polymerization, suspension polymerization, emulsion polymerization, and bulk polymerization, and a suitable polymerization catalyst or the like may be used. In one of the polymerization methods, for example, in the organic solvent, a polymerization initiator is added to a monomer which forms the structural unit represented by the above formula (1), the formula (2) and, if necessary, the formula (3), and is subjected to heat polymerization. The organic solvent to be used in this case can be appropriately selected from the preferable examples of the solvent contained in the composition for forming a photoresist for photolithography of the present invention to be described later. The polymerization initiator is, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2'-azobis (2-methylpropionate), benzoquinone peroxide, lauryl peroxide, heating temperature is generally 5 (TC to 80 ° C. The reaction time is generally 2 hours to 100 hours or 5 hours to 3 0小时。 The ratio of the polymer in the composition of the photoresist underlayer film for photolithography of the present invention may be from 0.5% by mass to 30% by mass based on the composition of the photoresist underlayer film. The component obtained by removing the solvent of the photoresist underlayer film described above is defined as a solid component. The solid component contains a polymer, a crosslinking agent, and other additives if necessary. The ratio of the polymer in the solid component is, for example, 70. The composition of the photo-lithography photoresist underlayer film of the present invention further contains a crosslinking agent. The crosslinking agent is not particularly limited, and it is preferred to use at least a mass of at least 98% by mass. 2 cross-linking compounds forming cross-linking substituents, such as hydroxymethyl, methoxymethyl segment a melamine-based compound, a substituted urea-based compound, an epoxy group-containing polymer compound, etc., which are crosslinked, preferably having 2 to 4 nitrogen atoms - 14 substituted by a methylol group or an alkoxymethyl group - The nitrogen-containing compound of 201241016. The content of the above-mentioned crosslinking agent in the composition for forming a photoresist for photolithography of the present invention is such that the component of the solvent formed by the formation of the photoresist underlayer film is defined as a solid component. (When the solid component contains a polymer, and a crosslinking agent, and if necessary, an additive to be added later), the content of the solid component relative to the composition of the photoresist underlayer film is 1% by mass to 50% by mass. Or 8% by mass to 40% by mass, or 15% by mass to 30% by mass. The above crosslinking agent can react with a crosslinking agent by self-condensation, but the aforementioned polymer is formed by reacting with a crosslinking agent in particular. The cross-linking structural unit can thus crosslink with a cross-linking functional group (hydroxyl group) in a structural unit derived from a (meth) acrylate compound having a hydroxyl group. The composition for forming a photo-shielding underlayer film for photolithography may further comprise a cross-linking catalyst such as p-toluenesulfonic acid, trifluoromethanesulfonic acid or pyridinium-P-toluenesulfonic acid. Salt, salicylic acid, hydrazine sulfonic acid, 5-sulfosalicylic acid, 4-chlorobenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, citric acid, benzoic acid, hydroxyl a sulfonic acid compound such as benzoic acid or a carboxylic acid compound. The crosslinking catalysts may be used alone or in combination of two or more. When a crosslinking catalyst is used, the photoresist for forming a photolithography underlying film of the present invention is used. The content of the cross-linking catalyst in the composition is 0.01% by mass to 0.1% by mass, or 0.1% by mass to 8% by mass, based on the content of the solid component of the composition forming the photoresist underlayer film. Or 〇. 5 mass% to 5 mass%. -15- 201241016 [Solvent] The composition for forming a photoresist film for photolithography of the present invention is further contained. The solvent used in the present invention may be one in which the polymer is dissolved, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl acetate, ethyl cellosolve acetate, Diethylene glycol monomethyl ether, diol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, xylene, A Ethyl ketone, cyclopentanone 'cyclohexanone, butyrolactone-methyl-2-pyrrolidone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-carboxylate, ethyl ethoxylate, hydroxyl Ethyl acetate, 2-hydroxy-3, methyl butyrate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl oxypropionate, 3-ethoxypropionic acid Ester, methyl pyruvate, ethyl propionate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate. The organic solvents may be used singly or in combination of two or more kinds. Further, it can be used as a high boiling point solvent such as propylene glycol monobutyl ether or propylene glycol monobutyl ether. Preferred among the above solvents are propylene glycol monomethyl ether, propylene glycol monomethyl acetate, ethyl lactate, butyl lactate, and cyclohexanone. Further, the solvent contained in the composition for forming the photoresist film for photolithography of the present invention is, for example, 50% by mass to 5% by mass of the composition for forming the photoresist underlayer film. [Other Additives] The composition for forming a photoresist film for photolithography of the present invention, which is soluble in a special cellosolve, diethyl propyl cresyl ester, propyl propyl 3-keto acid, etc. Proportion 99.5 Non-destructive-16-201241016 Under the effect of the present invention, various additives such as a surfactant, a subsiding agent, and a liquid flow adjusting agent may be additionally contained as necessary. The surfactant is an additive for improving the coatability of a composition for forming a photoresist underlayer film with respect to a substrate. A surfactant known as a nonionic surfactant or a fluorine-based surfactant can be used. Specific examples of the above surfactants include ethylene oxide alkyl ethers such as polyethylene oxide lauryl ether, polyethylene oxide stearyl ether, polyethylene oxide hexadecyl ether, and polyethylene oxide oleyl ether. Polyethylene oxide alkyl aryl ether, polyethylene oxide-polypropylene oxide block copolymer, sorbitol, polyethylene oxide octyl phenyl ether, polyethylene oxide phenyl phenyl ether Sugar anhydride laurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tri-hard Sorbitol fatty acid esters such as fatty acid esters, polyethylene oxide sorbitan monolaurate, polyethylene oxide sorbitan palmitate, polyethylene oxide sorbitan Non-ethylene oxide sorbitan fatty acid esters such as stearate 'polyethylene oxide sorbitan trioleate, polyethylene oxide sorbitan tristearate, etc. Ionic surfactant, yevitt [registered trademark] EF301, EF303, EF352 (Mitsubishi Materials E-Chemical Co., Ltd. (old Jemco)), Meikai Fan [Register Trademarks] F171, F173, R30 (DIC (share) system), Flora? 〇 43 0, 〇 431 (Sumitomo 31^ (share) system), Isaishi [registered trademark] AG710, Saffron [registration A fluorine-based surfactant such as S-3 82, SC101, SC102, SC103' SC104, SC105, SC106 (made by Asahi Glass Co., Ltd.), or an organic siloxane polymer KP34 1 (manufactured by Shin-Etsu Chemical Co., Ltd.) The surfactants may be added singly or in combination of two or more kinds. -17- 201241016 When the above surfactant is used, the content of the surfactant in the composition of the underlayer film for photolithography of the present invention is The solid content of the composition of the photoresist underlayer film is, for example, 3% by mass or less, preferably 1% by mass or less, more preferably 5% by mass or less. Next, the formation of the photoresist pattern of the present invention will be described. First, the composition for forming a photolithography underlayer film of the present invention is applied to a substrate used for manufacturing a precision integrated circuit device by an appropriate coating method such as a spin coater or a coater [for example, a germanium wafer coated with a hafnium oxide film, a tantalum nitride film or a tantalum oxide film, etc. a conductor substrate, a tantalum nitride substrate, a quartz substrate, a glass substrate (including an alkali-free glass, a low-alkali glass, a crystallized glass), a glass substrate on which an ITO film is formed, and then baked by a heating method such as a hot plate. Hardening to form a photoresist underlayer film. The baking conditions after coating may be appropriately selected from a baking temperature of 80 ° C to 250 ° C and a baking time of 0.3 minutes to 60 minutes, preferably as '150 From 0.5 ° C to 5 5 ° C for 0.5 minutes to 5 minutes. By baking under such conditions, the crosslinking site of the hydroxyl group or the like in the structural unit of the polymer can be reacted with the crosslinking agent to form a crosslinked structure. Crosslinking the polymer contained in the composition for forming a photoresist film for photolithography of the present invention can increase the parental density of the crosslinked polymer. Further, the film thickness of the photoresist underlayer film is Ο.ΟΟΙηηι to 3.0μηι, preferably 0·002μηι to Ι.Ομηι, more preferably 0.003μηι to 0.5μηιβ. Next, a photoresist film is formed on the underlayer film of the photoresist. The formation of the photoresist film can be carried out by a general method of applying a photoresist solution to the underlayer film of the photoresist and baking it. The photoresist coated on the upper layer of the photoresist underlayer film obtained by the composition for forming the photolithography underlayer film of the present invention may be a laser, ArF excimer mine with respect to KrF quasi-minute -18-201241016 sub-laser The shot, the EUV, the electron beam, and the like are photosensitive, and are not particularly limited, and any of a negative type or a positive type can be used. The photoresist is, for example, a positive photoresist containing a novolak resin and 1,2-naphthoquinonediazide sulfonate, and a binder containing photoacids having a base which accelerates the dissolution rate of hydrazine by acid decomposition. Chemically reinforced photoresist of the agent, a low molecular compound containing an alkali dissolution rate which enhances the photoresist by acid decomposition, and a chemically reinforced photoresist of an alkali soluble binder and a photoacid generator, which have decomposition by acid a binder which enhances the alkali dissolution rate and a low molecular compound which accelerates the alkali dissolution rate of the photoresist by acid decomposition, and a chemically amplified photoresist of a photoacid generator, which contains an alkali dissolution by decomposition of an electron beam A non-chemically-enhanced photoresist of a binder based on a speed, and a non-chemically-enhanced photoresist containing a binder having a portion which changes the rate of alkali dissolution by electron beam cutting. Specifically, for example, Sumitomo Chemical Co., Ltd. trade name PAR710, PAR855; JSR (share) product name AR2772JN; Shin-Etsu Chemical Co., Ltd. SEPR430; Dawu Chemical Co., Ltd. (old Lomian company) product name APEX-X . Also known as Proc. SPIE, Vol. 3999, 330-334 (2000), Proc. SPIE, Vol. 3999, 357-364 (2000), and Proc. SPIE, Vol. 3 999, 3 65-3 74 (2 000 The fluorine atom-containing polymer-based photoresist described in the above. Next, the photoresist is formed by a certain mask (mask) with respect to the photoresist film formed on the upper layer of the photoresist underlayer film. For exposure, for example, KrF excimer laser, ArF excimer laser, EUV can be used, and a mask (mask) is not required for electron beam exposure. After exposure, if necessary, post-exposure heating (PEB: Post Exposure Bake) can be performed. The conditions for heating after exposure may be appropriately selected from the range of heating temperature of 80 ° C to 150 ° C and heating time of 0.3 minutes to 60 minutes. A good photoresist pattern can be obtained by developing, cleaning and drying the photoresist film after exposure. The developing solution used for the photoresist film formed using the positive photoresist may be an inorganic base such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium citrate, sodium decanoate or ammonia, or ethylamine. a first-grade amine such as η-propylamine, a second-grade amine such as diethylamine or di-n-butylamine; a tertiary amine such as triethylamine or methyldiethylamine; Alkali such as methyl alcoholamine or triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, quaternary ammonium salt such as choline, or cyclic amine such as pyrrole or piperidine An aqueous solution. Further, the aqueous solution of the base may be added with an appropriate amount of an alcohol such as isopropyl alcohol or a surfactant such as a nonionic surfactant. Among them, a preferred developing solution is an aqueous solution of a 4-grade ammonium salt, more preferably an aqueous solution of tetramethylammonium hydroxide. The conditions for development can be appropriately selected from the range of the development temperature of 5 ° C to 50 ° C and the development time of 1 sec to 300 sec. Thereafter, a portion of the photoresist underlayer film which is exposed by removing the photoresist film by the above-described step is removed by dry etching, whereby a desired pattern can be formed on the substrate. [Embodiment] Hereinafter, the present invention will be described in detail by way of 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 4 are the results of gel permeation chromatography (hereinafter referred to as GPC for short). In the measurement, the GPC device manufactured by Tosoh Corporation was used, and the measurement conditions were as follows. -20 - 201241016 GPC pipe column: Shodex [registered trademark], Asahipak [registered trademark] (Showa Denko (share))

Column temperature: 40 ° C Solvent: n, n-dimethylformamide (dmf) Flow rate: 0 · 6 m 1 /min Standard sample: polystyrene (Dongsuo (share))

Detector: RI <Synthesis Example 1: ?0^8/11?1^8/〇8[14八=34/33/33(% by mass)&gt; p-hydroxyphenyl methacrylate (referred to as PQMA) 2.72g, 2-hydroxypropyl methacrylate (referred to as HPMA, manufactured by Tokyo Chemical Industry Co., Ltd.) 2.64g and r-butyrolactone methacrylate (referred to as GBLMA, Osaka Organic Chemistry) 2.64 g of Industrial Co., Ltd. was dissolved in 22.64 g of ethyl lactate, and polymerized by radical polymerization. After the reaction, the mixture was cooled to obtain a polymer solution having a solid content of 20% by mass. GPC analysis of the polymer in the obtained solution showed a weight average molecular weight of 1,400,400 in terms of standard polystyrene. <Synthesis Example 2: PQMA/HPMA/GBLMA = 20/47/3 3 (% by mass)&gt; P-hydroxyphenyl methacrylate (referred to as PQMA, manufactured by Showa Polymer Co., Ltd.) 1.60 g, 2-hydroxyl Propyl methacrylate (referred to as HPMA, manufactured by Tokyo Chemical Industry Co., Ltd.) 3.76g and r-butyrolactone methacrylate (referred to as GBLMA, Osaka Organic Chemical Industry Co., Ltd.-21 - 201241016) 2.64g dissolved in lactic acid In the 22.64 g of ethyl vinegar, it was polymerized by radical polymerization. After the reaction, the polymer solution of 20% by mass of the solid component was obtained. GPC analysis of the polymer in the obtained solution 'Results The weight average molecular weight in terms of standard polystyrene was 1,4,700 ° <Synthesis Example 3: PQMA/HPMA/GBLMA = 50/17/33 (mass °/〇)&gt; P-hydroxyphenyl methacrylate (referred to as PQMA 'Showa Polymer Co., Ltd.) 4.0 〇 g, 2 hydroxypropyl methacrylate vinegar (referred to as HPMA, manufactured by Tokyo Chemical Industry Co., Ltd.) 1.3 6g and 2.64 g of r-butyrolactone methacrylate (referred to as GBLMA's Osaka Organic Chemical Industry Co., Ltd.) was dissolved in 22.64 g of ethyl lactate, and polymerized by radical polymerization. After the reaction, the polymer was obtained by cooling to 20% by mass of a solid component. GPC analysis of the polymer in the obtained solution was carried out. The result was a weight average molecular weight of 15,100 in terms of standard polystyrene. <Synthesis Example 4: PQMA/HPMA/OTDMA = 34/33/3 3 (mass °/〇)&gt; P-hydroxyphenyl methacrylate (referred to as PQMA, manufactured by Showa Polymer Co., Ltd.) 2.72 g, 2 -Hydroxypropyl methacrylate (abbreviated as HPMA, manufactured by Tokyo Chemical Industry Co., Ltd.) 2.64 g and 8- or 9-methacryloxy-4-oxatricyclo[5.2.1.0'6]nonane- 2.40 g of 3-ketone (abbreviated as OTDM A, manufactured by Mitsubishi Rayon Co., Ltd.) was dissolved in 22.64 g of ethyl lactate, and polymerized by radical polymerization. After the reaction, the mixture was cooled to obtain a polymer solution having a solid content of 20% by mass. GPC analysis of the polymer in the obtained solution revealed that the weight average molecular weight in terms of standard polystyrene was -22-201241016,800 〇&lt;Example 1&gt; in 5 g of the solution containing the polymer lg obtained in the above Synthesis Example 1 After mixing 0.25 g of tetramethoxymethyl glycoluril (Japan Syndic Co., Ltd., trade name: POWDERLINK [registered trademark] 1174) and 0.0156 g of pyridine gun-P-toluenesulfonate, the mixture was dissolved in lactic acid. A solution of ethyl ester 20.43 g and propylene glycol monomethyl ether acetate 10.47 g was obtained. Thereafter, it was filtered using a polyethylene microfilter having a pore size of Ο.ΙΟμιη, and then filtered using a polyethylene microfilter having a pore size of 〇. 5 μηι to prepare a composition for forming a photoresist underlayer film. &lt;Example 2&gt; In a solution containing 5 g of the polymer lg obtained in the above Synthesis Example 2, tetramethoxymethylglycoluril (Japan Sitike Co., Ltd., trade name: POWDERLINK [registered trademark] 1174) 0.25 was mixed. g and pyridine gun-P-toluenesulfonate 0_0156g after the mixture was dissolved in ethyl lactate 20.43g and propylene glycol monomethyl ether acetate l〇.47g solution. Thereafter, it was filtered using a polyethylene microfilter having a pore size of 0.10 μηι, and then filtered using a polyethylene microfilter having a pore size of 〇. 5 μηι to prepare a composition for forming a photoresist underlayer film. &lt;Example 3&gt; In a solution containing 5 g of the polymer ig obtained in the above Synthesis Example 3, tetramethoxymethylglycoluril (Japan Sitike Co., Ltd., trade name: POWDERLINK [registered trademark] 1174) 0.25 was mixed. g and pyridinium-P-toluenesulfonic acid-23-201241016 salt 0.0156 g after the solution was dissolved in 20.43 g of ethyl lactate and 10.47 g of propylene glycol monomethyl ether acetate. Thereafter, it was filtered using a polyethylene microfilter having a pore size of Ο.ΙΟμιη, and then filtered using a polyethylene microfilter having a pore size of 〇. 5 μm to prepare a composition for forming a photoresist underlayer film. &lt;Example 4&gt; In a solution containing 5 g of the polymer ig obtained in the above Synthesis Example 4, tetramethoxymethylglycoluril (Japan Sitike Co., Ltd., trade name: POWDERLINK [registered trademark] 1174) 0.25 was mixed. After g and 0.0156 g of pyridinium-P-toluenesulfonate, the mixture was dissolved in a solution of 20.43 g of ethyl lactate and 10.47 g of propylene glycol monomethyl ether acetate. Thereafter, it was filtered using a polyethylene microfilter having a pore size of 〇·1 μ μm, and then filtered using a polyethylene microfilter having a pore size of 〇. 5 μm to prepare a composition for forming a photoresist underlayer film. &lt;Comparative Example 1&gt; A crosslinking agent represented by the following formula (5), which is a copolymer of the following formula (4) containing a polymer, and a pyridine gun-oxime-toluene ^ @$ are formed to form a photoresist. The composition of the underlying film. -24- 201241016 [化8] Η}

A/B=5 (V50(Wt%) [Chemical 9]

[blending test with photoresist] The composition for forming a photoresist underlayer film prepared in Examples 1 to 4 of the present invention, and the photoresist underlayer film shown in Comparative Example 1 were each used by a spin coater. The composition is coated on a tantalum wafer. The hot plate was baked at 205 ° C for 1 minute to form a photoresist underlayer film (film thickness Ο.ΙΟμηι). A commercially available photoresist solution (manufactured by Sumitomo Chemical Co., Ltd., trade name: PAR8 5 5) was applied over the photoresist underlayer film using a spin coater, and then baked at 100 ° C for 1 minute on a hot plate to form light. Resistor film (120 nm). After exposure with an exposure device, heat exposure at 1〇5 °C for 1 minute (PEB: Post Exposure -25- 201241016

Bake). After developing and cleaning the photoresist film, the film thickness of the photoresist underlayer film was measured, and the photoresist underlayer film and light obtained by forming the composition of the photoresist underlayer film prepared in Examples 1 to 4 were confirmed. The resist film will not be blended. [Measurement of Dry Etching Rate] The composition for forming a photoresist underlayer film prepared in Examples 1 to 4 of the present invention and the composition for forming a photoresist underlayer film shown in Comparative Example 1 were each coated with a spin coater. On the wafer. The hot plate was heated at 2 0 ° C for 1 minute to form a photoresist underlayer film. Next, using the RIE series ES401 manufactured by Seonti Co., Ltd., the dry etching rate was measured under the condition that CF4 was a dry etching gas. A photoresist (manufactured by Sumitomo Chemical Co., Ltd., trade name: PAR7 10) was applied onto a tantalum wafer by a spin coater, and a photoresist film was formed in the same manner as described above. Next, using the RIE series ES401 manufactured by Seonti, Japan, the dry etching rate was measured under the condition that CF4 was a dry etching gas. Comparing the five kinds of photoresist underlayer films obtained by forming the composition of the photoresist underlayer film of each of Examples 1 to 4 and Comparative Example 1, and the photoresist film obtained by the above-mentioned photoresist solution prepared by Sumitomo Chemical Co., Ltd. Erosion speed. The ratio of the dry etching speed of the underlying film of the photoresist relative to the dry etching rate of the photoresist film (the selection ratio of the dry etching rate) is shown in Table 1. The selection ratio of the dry etching rate of the photoresist underlayer film obtained from the composition for forming the photoresist underlayer film of each of the examples was larger than that of the photoresist underlayer film obtained by the composition for forming the photoresist underlayer film of Comparative Example 1. -26- 201241016 _ Selection ratio of dry etching speed. Example 1 Example 2 Example 3 Example 4 Comparative Example 1 1.30 1.34 1.27 1.21 - 1.10 [Formation of photoresist pattern] The preparation of Example 1 of the present invention The composition forming the photoresist underlayer film was spin-coated on the tantalum wafer 'heated at 205 ° C for 1 minute to form a photoresist underlayer film. After the EUV photoresist solution (methacrylate resin-based photoresist) was spin-coated on the underlayer film of the photoresist, it was heated to form a photoresist film. Exposure was carried out using an EUV exposure apparatus (EUV-ADT manufactured by ASML) under conditions of ΝΑ = 0.25 and σ = 0.5. After the exposure, the ΡΕΒ' cold plate was cooled to room temperature, and then developed and cleaned to form a photoresist pattern. The evaluation is based on whether a line and space of 30 nm are formed and the line roughness (LER) of the pattern is observed from above. Comparative Example 2 is a substrate in which HMDS (hexamethyldioxane) treatment was carried out using a ruthenium wafer, and the above test was carried out instead of forming a photoresist underlayer film. In the present specification, in the line and space pattern, when the cross section of the substrate in the vertical direction is a rectangular shape, it is evaluated as "good", and when the cross section is a ladder (a table shape) or a drag shape, it is evaluated as "may" and the pattern is disintegrated. It is evaluated as “not possible” when the image is poorly formed and the line and space pattern cannot be formed. The LER was measured by using Critical Dimension Scanning Electron Microscopy (CD-SEM), and the position of the line end of the pattern -27-201241016 was examined by the top-by-side method, and the deviation of the position was quantified as LER. A smaller LER means less deviation is preferred. Specifically, in the white strip width measured by CD-SEM, the line width of 400 points in the portion from the bottom to the top of the pattern is 70%, and the 3σ of the 値 is LER値. Where σ indicates the standard deviation. When the depth of focus (DOF) is measured, the exposure is based on the best focus position, and the exposure is performed by shifting the focus position up and down by 20 nm, and then the development and cleaning processes are performed to form the line and space of the photoresist pattern. Within ±10% of the line width for the allowable range of the line pattern width, the focus range of no pattern disintegration or pattern deformation is the DOF limit. [Table 2] 30 nm LER (nm) Formation line and space 30 nm pattern Example 1 Good 4.0 Comparative Example 2 Can be &gt; 4.5 [Table 3] 30 nm line and space 28 nm line and space DOF limit DOF limit Example 1 160 nm 120 nm As shown in Table 2, when the composition for forming a photoresist underlayer film prepared in Example 1 of the present invention was compared with Comparative Example 2, LER値 was small, and it was confirmed that the pattern size accuracy in the production step was high. LER値 generally wants to be below 4. Onm. "&gt;4.5" in Table 2 means that LER値 is larger than 4.5 nm. Further, as shown in Table 3, when the group of the photoresist-forming underlayer film -28-201241016 obtained in Example 1 of the present invention was used, it was confirmed that the width of the micro-line pattern of 3 Onm and 28 nm could be sufficient. The DOF limit. -29-

Claims (1)

201241016 VII. Patent application scope: 1. A composition for forming a lower film for a photolithography photoresist, which is a polymer containing a structural unit represented by the following formulas (1) and (2), and cross-linking Agent and solvent, (1A) (2) (wherein, Ri and R2 each independently represent a hydrogen atom or a methyl group, 1 is a single bond, or a linear or branched alkyl group having 1 to 13 carbon atoms; A valent bond group, A is an aromatic ring group having at least one substituent having a hydroxyl group, and D is a linear or branched hydroxyalkyl group having 1 to 13 carbon atoms). 2. The composition for forming a photoresist film for photolithography according to the first aspect of the invention, wherein the polymer is a copolymer having a structural unit represented by the following formula (3), [Chemical 2] -30- (3) 201241016 (wherein R3 represents a hydrogen atom or a methyl group. 'L2 represents a single bond or a linear or branched alkyl group having 1 to 13 carbon atoms. E represents an internal vinegar ring. Base or a group containing an adamantane ring). 3. The composition for forming a photo-lithography photoresist underlayer film according to claim 1 or 2, further comprising a cross-linking catalyst. 4. A method for forming a photoresist pattern, which comprises The step of forming a photoresist film underlayer film for coating a photolithography film according to any one of claims 1 to 3, and then baking the film to form a photoresist underlayer film, forming a film on the underlying photoresist film The step of the photoresist film is a step of exposing the semiconductor substrate covered by the photoresist underlayer film and the photoresist film, and a step of developing the photoresist film by a developing solution after the exposure. 5. A method of forming a photoresist pattern according to claim 4, wherein the exposure is performed using extreme ultraviolet rays. -31 - 201241016 IV. Designated representative map: (1) The representative representative of the case is: No (2) The symbol of the representative figure is a simple description: No 201241016 V. If there is a chemical formula in this case, please reveal the best indication of the characteristics of the invention. Chemical formula: -4-