Composition for forming resist under film having improved film density

Abstract

The present invention addresses the problem of providing a resist underlayer film-forming composition for forming a resist underlayer film having high film density, hardness, Young's modulus, and distortion resistance (bending resistance of a pattern), thereby having high etching resistance. [Solution] A composition for forming a resist underlayer film, which contains a novolac resin having a repeating unit structure represented by formula (1) (in formula (1), each of a group A and a group B is an organic group having an aromatic ring, a fused aromatic ring, or a fused aromatic heterocyclic ring; the hydrogen atoms on the ring in the group A and / or the group B are each substituted by two or more monovalent or divalent chemical groups of the same type or different types selected from the group consisting of a chemical group (a) that increases in mass by oxidation, a chemical group (b) that is formed by crosslinking by heating, and a chemical group (c) that induces phase separation during curing. ). The composition further comprises a cross-linking agent, an acid, and / or an acid generator. And a method for producing a resist underlayer film, which is obtained by applying the composition for forming a resist underlayer film on a semiconductor substrate and firing the same.

Description

[0001] This application is a divisional application of patent application No. 201780025989.3, filed on April 25, 2017, entitled "Composition for forming resist underlayer film with improved film density". TECHNICAL FIELD

[0002] The present application relates to a composition for forming a resist underlayer film with improved film density, and a manufacturing method of a semiconductor device using the same. BACKGROUND

[0003] Polymerization of polymer resins is widely studied, and polymers containing a ring structure such as novolak are widely used in fine fields such as photoresists and general fields such as members of automobiles and houses. In addition, the above-mentioned polymers are also applicable to special uses because they are also high in heat resistance, and thus development is now being conducted worldwide. In general, it is known that benzene, naphthalene, anthracene, pyrene, fluorene and the like structures are monomers containing a ring structure, and it is known that these monomers form novolak with monomers having an aldehyde group. On the other hand, it is clear that carbazole having a similar structure to fluorene also exhibits the same characteristics, and both monomers are polymerized by reacting a part of the benzene ring adjacent to the five-membered ring.

[0004] On the other hand, in the manufacture of semiconductor devices, fine processing has been performed by using a photoresist composition in lithography. The above-mentioned fine processing is a processing method in which a thin film of a photoresist composition is formed on a processed substrate such as a silicon wafer, active light such as ultraviolet rays is irradiated thereon through a mask pattern on which a semiconductor device pattern is drawn, and development is performed, and the resulting photoresist pattern is used as a protective film to perform etching treatment on the processed substrate such as a silicon wafer. However, in recent years, the progress of high integration of semiconductor devices, and the tendency of the active light used to be short-wavelength from KrF excimer laser (248 nm) to ArF excimer laser (193 nm). Along with this, the influence of the diffuse reflection of active light from the substrate and the standing wave is a big problem. Therefore, a method of providing an antireflection film between the photoresist and the processed substrate has been widely studied.

[0005] In the future, if the micropatterning of the resist pattern is performed, problems such as resolution, collapse of the resist pattern after development are generated, and thinning of the resist film is desired. Therefore, it is difficult to obtain a sufficient resist pattern film thickness for substrate processing, and a process is required in which not only the resist pattern but also a resist underlayer film produced between the resist and the semiconductor substrate subjected to processing has a function as a mask at the time of substrate processing. As such a resist underlayer film for the process, unlike the conventional high-etching rate (fast etching speed) resist underlayer film, a lithography resist underlayer film having a selectivity ratio of dry etching speed close to that of the resist, a lithography resist underlayer film having a selectivity ratio of dry etching speed smaller than that of the resist, and a lithography resist underlayer film having a selectivity ratio of dry etching speed smaller than that of the semiconductor substrate are required.

[0006] As the polymer for the above-described resist underlayer film, for example, the following polymers are exemplified.

[0007] A resist underlayer film-forming composition using carbazole is exemplified (see Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4).

[0008] Prior Art Documents

[0009] Patent Documents

[0010] Patent Document 1: International Publication WO2010 / 147155 Pamphlet

[0011] Patent Document 2: International Publication WO2012 / 077640 Pamphlet

[0012] Patent Document 3: International Publication WO2013 / 005797 Pamphlet

[0013] Patent Document 4: International Publication WO2014 / 092155 Pamphlet SUMMARY

[0014] PROBLEMS TO BE SOLVED BY THE INVENTION

[0015] An object of the present application is to provide a resist underlayer film-forming composition for use in a lithography process in the manufacture of a semiconductor device using a novolak resin. Furthermore, an object of the present application is to provide a lithography resist underlayer film which does not intermix with a resist layer, has high dry etching resistance, has high heat resistance, and has a low amount of sublimates.

[0016] Further, an object of the present application is to provide a resist underlayer film-forming composition for forming a resist underlayer film which has high film density, hardness, Young's modulus, and Wiggling resistance (bending resistance of a pattern), and based on this, has high etching resistance.

[0017] Method for solving the problem

[0018] In the present invention, as a first aspect, there is provided a composition for forming an underlayer film of a resist, which comprises a novolak resin having a repeating unit structure represented by the following formula (1),

[0019]

[0020] (In formula (1), each of group A and group B is independently an organic group having an aromatic ring, a condensed aromatic ring, or a condensed aromatic heterocycle, and the organic group has the following structure: a hydrogen atom bonded to a carbon atom in the aromatic ring, the condensed aromatic ring, or the condensed aromatic heterocycle in the group A or the group B or both groups is replaced by two or more monovalent or divalent chemical groups of the same kind or different kinds selected from the following chemical group (a), the chemical group (b), and the chemical group (c), the chemical group (a) undergoes mass increase by oxidation, the chemical group (b) undergoes crosslinking formation by heating, and the chemical group (c) induces phase separation in curing, and in the case where the above chemical group is divalent, the above rings can be bonded to each other via the chemical group or condensed with the chemical group.)

[0021] As a second aspect, there is provided the composition for forming an underlayer film of a resist according to the first aspect, wherein the organic group having an aromatic ring, a condensed aromatic ring, or a condensed aromatic heterocycle is an organic group having one or more benzene rings, naphthalene rings, or condensed rings of benzene rings and heterocycles,

[0022] As a third aspect, there is provided the composition for forming an underlayer film of a resist according to the first aspect or the second aspect, wherein the novolak resin represented by formula (1) has a structure in which hydrogen atoms in the aromatic ring, the condensed aromatic ring, or the condensed aromatic heterocycle are replaced by two or more chemical groups selected from the chemical group (a), the chemical group (b), the chemical group (c), a combination of the chemical group (a) and the chemical group (b), a combination of the chemical group (a) and the chemical group (c), a combination of the chemical group (b) and the chemical group (c), and a combination of the chemical group (a), the chemical group (b), and the chemical group (c),

[0023] As a fourth aspect, there is provided the composition for forming an underlayer film of a resist according to the third aspect, wherein the novolak resin represented by formula (1) has a structure in which at least one hydrogen atom bonded to a carbon atom in the aromatic ring, the condensed aromatic ring, or the condensed aromatic heterocycle in each of group A and group B is replaced by two chemical groups of the same kind or different kinds selected from the chemical group (b) or two chemical groups selected from the chemical group (a) and the chemical group (b), respectively, and two chemical groups are introduced in the unit structure,

[0024] As the 5th aspect, the composition for forming a resist underlayer film according to any one of the 1st to 4th aspects, the chemical group (a) is a methyl group, a thioether group, or a combination thereof,

[0025] As the 6th aspect, the composition for forming a resist underlayer film according to any one of the 1st to 5th aspects, the chemical group (b) is an amino group, a carboxyl group, a carboxylic acid alkyl ester group, a nitro group, a hydroxyl group, an ether group, or a combination thereof,

[0026] As the 7th aspect, the composition for forming a resist underlayer film according to any one of the 1st to 6th aspects, the chemical group (c) is a fluoroalkyl group,

[0027] As the 8th aspect, the composition for forming a resist underlayer film according to any one of the 1st to 7th aspects, further comprising a crosslinking agent,

[0028] As the 9th aspect, the composition for forming a resist underlayer film according to any one of the 1st to 8th aspects, further comprising an acid and / or an acid generator,

[0029] As the 10th aspect, a method for manufacturing a resist underlayer film, wherein a resist underlayer film is obtained by baking a composition for forming a resist underlayer film according to any one of the 1st to 9th aspects applied on a semiconductor substrate,

[0030] As the 11th aspect, a method for manufacturing a semiconductor device, comprising the steps of: forming a resist underlayer film on a semiconductor substrate from a composition for forming a resist underlayer film according to any one of the 1st to 9th aspects; forming a resist film on the resist underlayer film; forming a resist pattern by irradiation with light or electron beams and development; etching the underlayer film through the formed resist pattern; and processing the semiconductor substrate through the patterned underlayer film, and

[0031] As the 12th aspect, a method for manufacturing a semiconductor device, comprising the steps of: forming a resist underlayer film on a semiconductor substrate from a composition for forming a resist underlayer film according to any one of the 1st to 9th aspects; forming a hard mask on the resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern by irradiation with light or electron beams and development; etching the hard mask through the formed resist pattern; etching the underlayer film through the patterned hard mask; and processing the semiconductor substrate through the patterned resist underlayer film.

[0032] Effects of the Invention

[0033] By the resist underlayer film forming composition of the present application, mixing of the upper layer of the resist underlayer film with a layer coated thereon can be prevented, and a good pattern shape of the resist can be formed.

[0034] The resist underlayer film forming composition of the present application can also be endowed with the performance of efficiently suppressing reflection from a substrate, and can also have the effect of an antireflection film for exposure light.

[0035] By the resist underlayer film forming composition of the present application, an excellent resist underlayer film having a selectivity ratio of dry etching rate close to that of a resist, a selectivity ratio of dry etching rate smaller than that of a resist, and a selectivity ratio of dry etching rate smaller than that of a semiconductor substrate can be provided.

[0036] In order to prevent collapse of a resist pattern after development as the resist pattern is miniaturized, thinning of the resist is performed. For such a thin resist, there are processes in which a resist pattern is transferred to an underlayer film by an etching process, the underlayer film is used as a mask to perform processing of a substrate, and processes in which the above process is repeated, a pattern transferred to the underlayer film is further transferred to an underlayer film using a different gas composition, and finally processing of a substrate is performed. The resist underlayer film and the forming composition thereof of the present application are effective for such processes, and when a substrate is processed using the resist underlayer film of the present application, sufficient etching resistance with respect to the processed substrate (for example, a thermal oxide film, a silicon nitride film, a polysilicon film, and the like on a substrate) is obtained.

[0037] Furthermore, the resist underlayer film of the present application can be used as a planarization film, a resist underlayer film, a contamination preventing film for a resist layer, and a film having dry etching selectivity. Thus, resist pattern formation in a photolithography process of semiconductor production can be easily and accurately performed.

[0038] There is a process in which a resist underlayer film formed from the resist underlayer film forming composition according to the present application is formed on a substrate, a hard mask is formed on the resist underlayer film, a resist film is formed on the hard mask, a resist pattern is formed by exposure and development, the resist pattern is transferred to the hard mask, the resist pattern transferred to the hard mask is transferred to the resist underlayer film, and the resist underlayer film is used to process a semiconductor substrate. In this process, the hard mask is formed by a coating type composition containing an organic polymer, an inorganic polymer, and a solvent, and by vacuum evaporation of an inorganic substance. In vacuum evaporation of an inorganic substance (for example, silicon oxynitride), the evaporated substance is deposited on the surface of the resist underlayer film, but at this time the temperature of the surface of the resist underlayer film rises to about 400°C. The polymer used in the present application has extremely high heat resistance, and does not deteriorate even when the evaporated substance is deposited.

[0039] Further, the resist underlayer film obtained by the composition for forming a resist underlayer film of the present application has the hydrogen atoms bonded to the carbon atoms on the aromatic ring, the fused aromatic ring, or the fused aromatic heterocycle (for example, benzene ring) in the unit structure of the polymer contained therein substituted with chemical groups having specific functions, and thus, compared with the resist underlayer film having a polymer whose unit structure contains the above-described aromatic ring, fused aromatic ring, or fused aromatic heterocycle which is not substituted with these chemical groups, the film density and hardness are improved, the twist resistance (bending resistance of the pattern) is high, and the etching resistance is also improved. DETAILED DESCRIPTION

[0040] The present application is a composition for forming a resist underlayer film containing a novolak resin having a repeating unit represented by formula (1).

[0041] In formula (1), the group A and the group B are each independently an organic group having an aromatic ring, a fused aromatic ring, or a fused aromatic heterocycle, and have a structure in which the hydrogen atoms bonded to the carbon atoms on the aromatic ring, the fused aromatic ring, or the fused aromatic heterocycle in the group A or the group B or both groups are substituted with 2 or more monovalent or divalent chemical groups selected from chemical group (a) which undergoes mass increase by oxidation, chemical group (b) which undergoes crosslinking formation by heating, and chemical group (c) which induces phase separation in curing. In the case where the above-described chemical group is divalent, the above-described rings can be bonded to each other via the chemical group, or condensed with the chemical group.

[0042] The above-described aromatic ring, fused aromatic ring, or fused aromatic heterocycle can be one or more benzene rings, naphthalene rings, or fused rings of benzene rings and heterocycles. Thus, the group A and the group B can each independently be an organic group having one or more benzene rings, naphthalene rings, or fused rings of benzene rings and heterocycles.

[0043] Preferably, in formula (1), as the organic group A, there can be mentioned an organic group having benzene, naphthalene, carbazole, diphenylamine, trihydroxyphenyl ethane, or the like. The amino group contained in carbazole and diphenylamine corresponds to the above-described chemical group (b), and is a structure in which the hydrogen atoms of two benzene rings are substituted with a secondary amino group. In the case of trihydroxyphenyl ethane, it is a structure in which the hydrogen atoms of each benzene ring are substituted with a hydroxyl group.

[0044] In formula (1), as the organic group B, there can be mentioned an organic group having benzene, naphthalene, or the like.

[0045] The so-called two or more chemical groups recited herein exist in the following cases: two or more from chemical group (a), two or more from chemical group (b), two or more from chemical group (c), or two or more from both of chemical group (a) and chemical group (b), two or more from both of chemical group (a) and chemical group (c), two or more from both of chemical group (b) and chemical group (c), or two or more from all of chemical group (a), chemical group (b), and chemical group (c) (i.e., three or more).

[0046] The novolak resin of formula (1) can have a structure in which a hydrogen atom of an aromatic ring, a condensed aromatic ring, or a condensed aromatic heterocycle is substituted with two or more chemical groups selected from chemical group (a), chemical group (b), a combination of chemical group (a) and chemical group (b), a combination of chemical group (a) and chemical group (c), and a combination of chemical group (b) and chemical group (c), respectively. That is, it can have a structure in which a hydrogen atom of an aromatic ring, a condensed aromatic ring, or a condensed aromatic heterocycle of group A, group B, or both is substituted.

[0047] Further, the novolak resin of formula (1) can have a structure in which one hydrogen atom bonded to a carbon atom of an aromatic ring, a condensed aromatic ring, or a condensed aromatic heterocycle is substituted with two chemical groups selected from chemical group (b), or a combination of chemical group (a) and chemical group (b), respectively, in all (i.e., both group A and group B) of the aromatic ring, the condensed aromatic ring, or the condensed aromatic heterocycle in a unit structure, and a structure in which two chemical groups are introduced in the unit structure.

[0048] Chemical group (a) can be exemplified by, for example, a methyl group, a thioether group, or a combination thereof.

[0049] Chemical group (b) can be exemplified by, for example, an amino group, a carboxyl group, a carboxylic acid alkyl ester group, a nitro group, a hydroxyl group, an ether group, or a combination thereof.

[0050] The alkyl group of the carboxylic acid alkyl ester group can be exemplified by alkyl groups having 1 to 10 carbon atoms, and examples include methyl group, ethyl group, n-propyl group, isopropyl group, cyclopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, cyclobutyl group, 1-methyl-cyclopropyl group, 2-methyl-cyclopropyl group, n-pentyl group, 1-methyl-n-butyl group, 2-methyl-n-butyl group, 3-methyl-n-butyl group, 1,1-dimethyl-n-propyl group, 1,2-dimethyl-n-propyl group, 2,2-dimethyl-n-propyl group, 1-ethyl-n-propyl group, cyclopentyl group, 1-methyl-cyclobutyl group, 2-methyl-cyclobutyl group, 3-methyl-cyclobutyl group, 1,2-dimethyl-cyclopropyl group, 2,3-dimethyl-cyclopropyl group, 1-ethyl-cyclopropyl group, 2-ethyl-cyclopropyl group, n-hexyl group, 1-methyl-n-pentyl group, 2-methyl-n-pentyl group, 3-methyl-n-pentyl group, 4-methyl-n-pentyl group, 1,1-dimethyl-n-butyl group, 1,2-dimethyl-n-butyl group, 1,3-dimethyl-n-butyl group, 2,2-dimethyl-n-butyl group, 2,3-dimethyl-n-butyl group, 3,3-dimethyl-n-butyl group, 1-ethyl-n-butyl group, 2-ethyl-n-butyl group, 1,1,2-trimethyl-n-propyl group, 1,2,2-trimethyl-n-propyl group, 1-ethyl-1-methyl-n-propyl group, 1-ethyl-2-methyl-n-propyl group, cyclohexyl group, 1-methyl-cyclopentyl group, 2-methyl-cyclopentyl group, 3-methyl-cyclopentyl group, 1-ethyl-cyclobutyl group, 2-ethyl-cyclobutyl group, 3-ethyl-cyclobutyl group, 1,2-dimethyl-cyclobutyl group, 1,3-dimethyl-cyclobutyl group, 2,2-dimethyl-cyclobutyl group, 2,3-dimethyl-cyclobutyl group, 2,4-dimethyl-cyclobutyl group, 3,3-dimethyl-cyclobutyl group, 1-n-propyl-cyclopropyl group, 2-n-propyl-cyclopropyl group, 1-isopropyl-cyclopropyl group, 2-isopropyl-cyclopropyl group, 1,2,2-trimethyl-cyclopropyl group, 1,2,3-trimethyl-cyclopropyl group, 2,2,3-trimethyl-cyclopropyl group, 1-ethyl-2-methyl-cyclopropyl group, 2-ethyl-1-methyl-cyclopropyl group, 2-ethyl-2-methyl-cyclopropyl group, and 2-ethyl-3-methyl-cyclopropyl group, and the like.

[0051] The chemical group (c) can be exemplified by, for example, fluoroalkyl group. The fluoroalkyl group can be exemplified by partially fluorinated alkyl group, completely fluorinated alkyl group. Examples include trifluoromethyl group, and the like.

[0052] In the present application, a polymer is obtained by novolacification between an aromatic compound or a compound containing an aromatic group corresponding to the group A and an aromatic aldehyde corresponding to the group B. There are cases where the chemical group (a), the chemical group (b), and the chemical group (c) are introduced to the starting material of the novolacification reaction, and cases where they are introduced to the polymer which has been novolacified by the reaction.

[0053] As the acid catalyst used in the above condensation reaction, inorganic acids such as sulfuric acid, phosphoric acid, perchloric acid, and the like, organic sulfonic acids such as methanesulfonic acid, p-toluenesulfonic acid, p-toluenesulfonic acid monohydrate, and the like, carboxylic acids such as formic acid, oxalic acid, and the like are used. The amount of the acid catalyst used is variously selected depending on the kind of the acid used. Generally, 0.001 to 10,000 parts by mass, preferably 0.01 to 1,000 parts by mass, and more preferably 0.1 to 100 parts by mass, relative to 100 parts by mass of the compound corresponding to the group A of formula (1) is used.

[0054] The above condensation reaction can be performed even without a solvent, but is generally performed using a solvent. As the solvent, all can be used as long as the reaction is not hindered. Cyclic ethers such as tetrahydrofuran, dioxane, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and the like can be mentioned. Furthermore, if the acid catalyst used is a liquid acid catalyst such as formic acid, the acid catalyst can also function as the solvent.

[0055] The reaction temperature at the time of condensation is generally 40°C to 200°C. The reaction time is variously selected depending on the reaction temperature, but is generally about 30 minutes to 50 hours.

[0056] The weight average molecular weight Mw of the polymer obtained by the above operation is generally 600 to 1,000,000, or 600 to 200,000.

[0057] The unit structure of formula (1) can be exemplified as follows, for example.

[0058]

[0059]

[0060]

[0061]

[0062] The above polymer can be used by mixing other polymers in an amount of 30% by mass or less in the total polymer.

[0063] As the polymers, polyacrylate compounds, polymethacrylate compounds, polyacrylamide compounds, polymethacrylamide compounds, polyvinyl compounds, polystyrene compounds, polymaleimide compounds, polymaleic anhydride, and polyacrylonitrile compounds can be mentioned.

[0064] ​The composition for forming a resist underlayer film of the present application contains the above-mentioned polymer and a solvent. Furthermore, a crosslinking agent and an acid can be contained, and an acid generator, a surfactant, and the like can be contained as an additive as necessary. The solid content of the composition is 0.1 to 70 mass%, or 0.1 to 60 mass%. The solid content is the content ratio of the entire components after the solvent is removed from the composition for forming a resist underlayer film. The above-mentioned polymer can be contained in a ratio of 1 to 100 mass%, or 1 to 99.9 mass%, or 50 to 99.9 mass% in the solid content.

[0065] The weight average molecular weight of the polymer used in the present application is 600 to 1,000,000, or 600 to 200,000.

[0066] The composition for forming a resist underlayer film of the present application can contain a crosslinking agent component. As the crosslinking agent, melamine-based, substituted urea-based, or polymer-based compounds, and the like can be mentioned. A crosslinking agent having at least two crosslinking-forming substituents is preferable, and methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxymethylated benzoguanamine, methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, or the like can be mentioned. Furthermore, condensates of these compounds can also be used.

[0067] Furthermore, as the above-mentioned crosslinking agent, a crosslinking agent having high heat resistance can be used. As the crosslinking agent having high heat resistance, a compound having a crosslinking-forming substituent having an aromatic ring (for example, a benzene ring, a naphthalene ring) in the molecule can be preferably used.

[0068] The compound can be a compound having a partial structure of the following formula (3), or a polymer or an oligomer having a repeating unit structure of the following formula (4).

[0069] In formula (3), R 3 and R 4 are each a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms, n1 is an integer of 1 to 4, n2 is an integer of 1 to (5-n1), and (n1+n2) represents an integer of 2 to 5.

[0070] In formula (4), R 5 are each a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, R 6 is an alkyl group having 1 to 10 carbon atoms, n3 is an integer of 1 to 4, n4 is 0 to (4-n3), and (n3+n4) represents an integer of 1 to 4. The oligomer and the polymer can be used in a range of 2 to 100, or 2 to 50 in the number of repeating unit structures.

[0071] As the above-mentioned alkyl group having 1 to 10 carbon atoms, the above-mentioned examples can be given. As the above-mentioned aryl group having 6 to 20 carbon atoms, for example, phenyl group, naphthyl group, anthryl group, and the like can be given.

[0072]

[0073] The compounds of formula (4), formula (5), polymers, and oligomers are exemplified below.

[0074]

[0075]

[0076]

[0077] The above-mentioned compounds can be obtained as products of Asahi Organic Materials Co., Ltd., and Hyogo Chemical Industry Co., Ltd. For example, in the above-mentioned crosslinking agent, the compound of formula (4-21) can be obtained as a product of Asahi Organic Materials Co., Ltd., and under the trade name of TM-BIP-A.

[0078] The amount of the crosslinking agent to be added varies depending on the coating solvent to be used, the substrate to be used, the solution viscosity to be required, the film shape to be required, and the like, but is 0.001 to 80 mass% with respect to the total solid content, preferably 0.01 to 50 mass%, and further preferably 0.05 to 40 mass%. These crosslinking agents sometimes undergo crosslinking reactions caused by self-condensation, but in the case where the above-mentioned polymer of the present application has crosslinkable substituents, crosslinking reactions can occur with these crosslinkable substituents.

[0079] As the catalyst for promoting the above-mentioned crosslinking reaction in the present application, p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridine acidic compounds such as p-toluenesulfonic acid salt, salicylic acid, sulfosalicylic acid, citric acid, benzoic acid, hydroxybenzoic acid, naphthoic acid, and the like, and / or thermal acid generators such as 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, other alkyl esters of organic sulfonic acids, and the like. The amount to be incorporated is 0.0001 to 20 mass% with respect to the total solid content, preferably 0.0005 to 10 mass%, and preferably 0.01 to 3 mass%.

[0080] The coating-type underlayer film forming composition of the present application can be added with a photoacid generator in order to match the acidity of the photoresist coated on the upper layer in the photolithography process. As the preferred photoacid generator, for example, bis(4-tert-butylphenyl)iodonium triflate trifluoromethanesulfonic acid salt, triphenylsulfonium trifluoromethanesulfonic acid salt, and the like a salt-based photo-acid generator, a halogen-containing compound-based photo-acid generator such as phenyl-bis(trichloromethyl)-s-triazine, a sulfonic acid-based photo-acid generator such as benzoin tosylate, N-hydroxysuccinimide trifluoromethane sulfonate, and the like. The above photo-acid generator is contained in an amount of 0.2 to 10 mass% and preferably 0.4 to 5 mass% relative to the total solid content.

[0081] In the composition for forming a photoresist underlayer film according to the present application, in addition to the above-mentioned components, a light absorber, a rheology modifier, an adhesion aid, a surfactant, and the like can be further added as needed.

[0082] Further, as the light absorber, a commercially available light absorber described in "Industrial Pigment Technology and Market" (CMC Publishing), "Dye Handbook" (edited by Organic Synthesis Chemistry Association), for example, can be suitably used. Examples include C.I. Disperse Yellow 1, 3, 4, 5, 7, 8, 13, 23, 31, 49, 50, 51, 54, 60, 64, 66, 68, 79, 82, 88, 90, 93, 102, 114, and 124; C.I. Disperse Orange 1, 5, 13, 25, 29, 30, 31, 44, 57, 72, and 73; C.I. Disperse Red 1, 5, 7, 13, 17, 19, 43, 50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199, and 210; C.I. Disperse Violet 43; C.I. Disperse Blue 96; C.I. Fluorescent Brightener 112, 135, and 163; C.I. Solvent Orange 2 and 45; C.I. Solvent Red 1, 3, 8, 23, 24, 25, 27, and 49; C.I. Pigment Green 10; C.I. Pigment Brown 2; and the like. The above light absorber is generally contained in an amount of 10 mass% or less, and preferably 5 mass% or less, relative to the total solid content of the composition for forming a photoresist underlayer film.

[0083] The rheology modifier is added mainly to improve the flowability of the composition for forming a photoresist underlayer film, and in particular, to improve the film thickness uniformity of the photoresist underlayer film in the baking process, and to improve the filling property of the composition for forming a photoresist underlayer film into a hole. As specific examples, dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, butyl isodecyl phthalate, and the like can be given as phthalic acid derivatives, di-n-butyl adipate, diisobutyl adipate, diisooctyl adipate, octyl decyl adipate, and the like can be given as adipic acid derivatives, di-n-butyl maleate, diethyl maleate, dinonyl maleate, and the like can be given as maleic acid derivatives, methyl oleate, butyl oleate, tetrahydrofurfuryl oleate, and the like can be given as oleic acid derivatives, or n-butyl stearate, glycerol stearate, and the like can be given as stearic acid derivatives. These rheology modifiers are generally contained in an amount of less than 30 mass% relative to the total solid content of the composition for forming a photoresist underlayer film.

[0084] The adhesion auxiliary agent is added mainly for the purpose of improving the adhesion of the substrate or resist to the composition for forming a lower layer of resist, particularly for the purpose of preventing the resist from peeling off during development. As specific examples, chlorosilanes such as trimethylchlorosilane, dimethylvinylchlorosilane, methyldiphenylchlorosilane, chloromethyldimethylchlorosilane, alkoxysilanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethyivinylethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane, silazanes such as hexamethyldisilazane, N,N'-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine, trimethylsilylimidazole, silanes such as vinyltrichlorosilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-epoxypropoxypropyltrimethoxysilane, heterocyclic compounds such as benzotriazole, benzimidazole, indazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenz indazole, urazole, thiouracil, mercaptoimidazole, mercaptopyrimidine, ureas such as 1,1-dimethylurea, 1,3-dimethylurea, or thiourea compounds. These adhesion auxiliary agents are usually incorporated at a proportion of less than 5 mass%, preferably less than 2 mass%, relative to the total solid content of the composition for forming a lower layer of resist for lithography.

[0085] In the composition for forming an underlayer film of a resist for photolithography of the present application, a surfactant can be added in order to further improve the coatability on uneven surfaces without causing pinholes, streaks, and the like. As the surfactant, for example, polyoxyethylene alkyl ether such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkyl allyl ether such as polyoxyethylene octyl phenol ether and polyoxyethylene nonyl phenol ether; polyoxyethylene / polyoxypropylene block copolymer; sorbitan fatty acid ester such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate; polyoxyethylene sorbitan fatty acid ester such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate; nonionic surfactant; eftop EF301, EF303, and EF352 (manufactured by Tochem Products Corp., trade names); megafack F171, F173, R-30, R-40, R-40N (manufactured by DIC Corp., trade names); florad FC430 and FC431 (manufactured by Sumitomo 3M Co., Ltd., trade names); asahi guard AG710, surfon S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (manufactured by Asahi Glass Co., Ltd., trade names); fluorine-based surfactant; and silicone polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can be mentioned. The amount of the surfactant to be added is usually 2.0% by mass or less, preferably 1.0% by mass or less, relative to the total solid content of the composition for forming an underlayer film of a resist for photolithography of the present application. The surfactant can be added alone or in combination of two or more kinds.

[0086] In the present application, as a solvent for dissolving the above-mentioned polymer and cross-linking agent component, cross-linking catalyst, etc., ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-hydroxypropionic acid ethyl ester, 2-hydroxy-2-methylpropionic acid ethyl ester, ethoxy acetic acid ethyl ester, hydroxy acetic acid ethyl ester, 2-hydroxy-3-methylbutyric acid methyl ester, 3-methoxypropionic acid methyl ester, 3-methoxypropionic acid ethyl ester, 3-ethoxypropionic acid ethyl ester, 3-ethoxypropionic acid methyl ester, pyruvic acid methyl ester, pyruvic acid ethyl ester, acetic acid ethyl ester, acetic acid butyl ester, lactic acid ethyl ester, lactic acid butyl ester, etc. can be used. These organic solvents are used alone or in combination of two or more.

[0087] Further, propylene glycol monobutyl ether, propylene glycol monobutyl ether acetate, etc. can be used as a high-boiling solvent. Of these solvents, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, lactic acid ethyl ester, lactic acid butyl ester, and cyclohexanone, etc. are preferable for improving planarity.

[0088] Next, the resist pattern forming method of the present application will be described. The composition for forming a resist underlayer film is applied to a substrate (e.g., a transparent substrate such as a silicon / silicon dioxide-coated, glass substrate, ITO substrate, etc.) used in the manufacture of a precision integrated circuit element by a suitable coating method such as a spin coater, applicator, etc., and then baked to cure it, thereby producing a coated underlayer film. Here, the film thickness of the resist underlayer film is preferably 0.01 to 3.0 μm. Further, the conditions for baking after application are 80 to 350°C for 0.5 to 120 minutes. Then, a resist is applied directly to the resist underlayer film, or a resist is applied after forming one to a plurality of layers of coating film material on the coated underlayer film, and irradiation of light or electron rays is performed through a prescribed mask, and development, rinsing, and drying are performed, thereby obtaining a good resist pattern. If necessary, heating after irradiation of light or electron rays (PEB: Post Exposure Bake) can be performed. Further, the resist underlayer film from which the portion of the resist removed by development through the above-mentioned process is removed by dry etching, and the desired pattern is formed on the substrate.

[0089] The so-called resist used in the present application is a photoresist or an electron ray resist.

[0090] As the photoresist underlayer film of the present application, a positive or negative photoresist can be used. Examples of the photoresist include a positive photoresist composed of a novolak resin and 1,2-naphthoquinone diazide sulfonic acid ester, a chemically amplified photoresist composed of a binder having a group that increases the alkali solubility by acid decomposition and a photoacid generator, a chemically amplified photoresist composed of an alkali-soluble binder and a low-molecular compound that increases the alkali solubility of the photoresist by acid decomposition and a photoacid generator, a chemically amplified photoresist composed of a binder having a group that increases the alkali solubility by acid decomposition and a low-molecular compound that increases the alkali solubility of the photoresist by acid decomposition and a photoacid generator, a photoresist having a backbone with Si atoms, and the like. Examples of the photoresist include APEX-E manufactured by Rohm and Haas Company.

[0091] Further, as the electron beam resist applied to the upper portion of the photoresist underlayer film of the present application, a composition containing a resin having a main chain containing a Si-Si bond and a terminal aromatic ring and an acid generator that generates an acid by irradiation of an electron beam, or a composition containing a poly(p-hydroxystyrene) having a hydroxyl group substituted with an organic group containing an N-carboxy amine and an acid generator that generates an acid by irradiation of an electron beam, and the like can be used. In the latter electron beam resist composition, the acid generated from the acid generator by electron beam irradiation reacts with the N-carboxy amino group of the side chain of the polymer, the side chain of the polymer is decomposed into a hydroxyl group to exhibit alkali solubility, and the resist pattern is formed by dissolving in an alkali developer. Examples of the acid generator that generates an acid by irradiation of an electron beam include halogenated organic compounds such as 1,1-bis[p-chlorophenyl]-2,2,2-trichloroethane, 1,1-bis[p-methoxyphenyl]-2,2,2-trichloroethane, 1,1-bis[p-chlorophenyl]-2,2-dichloroethane, 2-chloro-6-(trichloromethyl)pyridine, triphenylsulfonium salts, diphenyliodonium salts, and the like. Salts, nitrobenzyl toluenesulfonate, dinitrobenzyl toluenesulfonate, and the like sulfonate esters. Salts, nitrobenzyl toluenesulfonate, dinitrobenzyl toluenesulfonate, and the like sulfonate esters.

[0092] The resist solution is baked at a baking temperature of 70 to 150°C and a baking time of 0.5 to 5 minutes after coating, and a resist film thickness in the range of 10 to 1000 nm is obtained. The resist solution, the developer, and the coating material described below can be coated by spin coating, dip coating, spray coating, or the like, but spin coating is particularly preferred. The resist is exposed through a prescribed mask. At the time of exposure, KrF excimer laser light (wavelength 248 nm), ArF excimer laser light (wavelength 193 nm), and EUV light (wavelength 13.5 nm), electron beams, or the like can be used. After exposure, post-exposure bake (PEB) can also be performed as needed. The post-exposure bake is appropriately selected from a heating temperature of 70 to 150°C and a heating time of 0.3 to 10 minutes.

[0093] As the developer for the resist having the resist underlayer film formed using the composition for forming a resist underlayer film of the present application, an aqueous solution of an inorganic base such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, a primary amine such as ethylamine, n-propylamine, a secondary amine such as diethylamine, di-n-butylamine, a tertiary amine such as triethylamine, methyldiethylamine, an alcohol amine such as dimethyl ethanolamine, triethanolamine, a quaternary ammonium salt such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline, a cyclic amine such as pyrrole, piperidine, and the like can be used. Further, an appropriate amount of an alcohol such as isopropyl alcohol, a surfactant such as a nonionic surfactant, and the like can be added to the above-described aqueous solution of a base and used. Among these, the preferred developer is a quaternary ammonium salt, and further preferred are tetramethylammonium hydroxide and choline.

[0094] Further, the development of the resist in the present application can use an organic solvent as the developer. The development is performed by a developer (solvent) after exposure of the resist. Thereby, in the case of using, for example, a positive photoresist, the photoresist of the unexposed portion is removed, and a pattern of the photoresist is formed.

[0095] As the developer, for example, methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, 4-methyl-4-methoxypentyl acetate, propylene glycol diacetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propyl-3-methoxypropionate, and the like can be given as examples. Further, a surfactant or the like can be added to these developers. As the developing conditions, the temperature is appropriately selected from 5 to 50°C, and the time is appropriately selected from 10 to 600 seconds.

[0096] In the present application, a semiconductor device can be manufactured by the following steps: a step of forming a resist underlayer film on a semiconductor substrate from a resist underlayer film-forming composition, a step of forming a resist film on the resist underlayer film, a step of forming a resist pattern by light or electron beam irradiation and development, a step of etching the resist underlayer film with the formed resist pattern, and a step of processing the semiconductor substrate with the patterned resist underlayer film.

[0097] In the future, if the micropatterning of the resist pattern is performed, problems such as resolution, collapse of the resist pattern after development, are generated, and thinning of the resist film is desired. Therefore, it is difficult to obtain a sufficient resist pattern film thickness for substrate processing, and a process is required in which not only the resist pattern but also the resist underlayer film produced between the resist and the semiconductor substrate subjected to processing has a function as a mask at the time of substrate processing. As the resist underlayer film for such a process, unlike the conventional high etching rate resist underlayer film, a lithography resist underlayer film having a dry etching rate selection ratio close to that of the resist, a lithography resist underlayer film having a dry etching rate selection ratio smaller than that of the resist, and a lithography resist underlayer film having a dry etching rate selection ratio smaller than that of the semiconductor substrate are required. Furthermore, such a resist underlayer film can be imparted with antireflection ability, and can have the function of the conventional antireflection film.

[0098] On the other hand, in order to obtain a fine resist pattern, a process in which the resist pattern is made finer than the pattern width at the time of development of the resist after dry etching of the resist underlayer film has also been used. As the resist underlayer film for such a process, unlike the conventional high etching rate antireflection film, a resist underlayer film having a dry etching rate selection ratio close to that of the resist is required. Furthermore, such a resist underlayer film can be imparted with antireflection ability, and can have the function of the conventional antireflection film.

[0099] In the present application, after the resist underlayer film of the present application is formed on a substrate, a resist can be directly applied to the resist underlayer film, or a resist can be applied after one layer to a plurality of layers of coating film materials are formed on the resist underlayer film as needed. Thereby, even in the case where the pattern width of the resist is narrowed and the resist is thinly coated in order to prevent pattern collapse, the processing of the substrate can be performed by selecting an appropriate etching gas.

[0100] That is, a semiconductor device can be manufactured by the following steps: a step of forming a resist underlayer film on a semiconductor substrate from a composition for forming the resist underlayer film, a step of forming a hard mask formed of a coating film material containing a silicon component or the like or a hard mask formed by evaporation (for example, silicon nitride oxide) on the resist underlayer film, a step of further forming a resist film on the hard mask, a step of forming a resist pattern by irradiation with light or electron rays and development, a step of etching the hard mask with a halogen-based gas through the formed resist pattern, a step of etching the resist underlayer film with an oxygen-based gas or a hydrogen-based gas through the patterned hard mask, and a step of processing the semiconductor substrate with a halogen-based gas through the patterned resist underlayer film.

[0101] The photoresist underlayer film forming composition of the present application, in consideration of the effect as an antireflection film, has a skeleton into which a light absorbing site is introduced, and therefore, there is no diffusant into the photoresist at the time of heat drying, and further, the light absorbing site has sufficiently large light absorbing property, and therefore, the antireflection effect is high.

[0102] The photoresist underlayer film forming composition of the present application has high heat stability, and can prevent contamination of the upper layer film by the decomposate at the time of baking, and further, can have a margin for the temperature margin of the baking step.

[0103] Further, the photoresist underlayer film forming composition of the present application, depending on the process conditions, can be used as a film having the function of preventing light reflection, and further, the function of preventing the interaction of the substrate and the photoresist, or the function of preventing the adverse effect of the material used for the photoresist or the substance generated at the time of exposure of the photoresist on the substrate.

[0104] Example

[0105] (Synthetic Example 1)

[0106] In a 100 mL two-necked flask, carbazole (manufactured by Tokyo Chemical Industry Co., Ltd.) 9.00 g, p-tolualdehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 6.47 g, propylene glycol monomethyl ether acetate 38.52 g, and methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 1.04 g were charged. Then, heating was performed until 150°C, and reflux stirring was performed for about 1.5 hours. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 18.73 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction filtered, and the filtrate was dried at 60°C under reduced pressure for one night. Thus, a powder resin 12.2 g was obtained. The obtained polymer corresponds to formula (1-1). The weight average molecular weight Mw measured by GPC in polystyrene conversion was 82,700, and the polydispersity Mw / Mn was 13.5.

[0107] (Synthetic Example 2)

[0108] In a 100 mL two-necked flask, carbazole (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.00 g, p-formylbenzoic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 7.19 g, propylene glycol monomethyl ether acetate 18.79 g, propylene glycol monomethyl ether 18.79 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.92 g were added. Then, heating was performed until 150°C, and stirring was performed for about 3.5 hours under reflux. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 22.25 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a resin of a powder 13.7 g was obtained. The obtained polymer corresponds to formula (1-2). The weight average molecular weight Mw measured by GPC in terms of polystyrene was 24,800, and the polydispersity Mw / Mn was 4.30.

[0109] (Synthetic Example 3)

[0110] In a 100 mL two-necked flask, carbazole (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.00 g, p-formylbenzoic acid methyl ester (manufactured by Tokyo Chemical Industry Co., Ltd.) 7.86 g, propylene glycol monomethyl ether acetate 24.14 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.23 g were added. Then, heating was performed until 150°C, and stirring was performed for about 2 hours under reflux. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 39.08 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a resin of a powder 13.3 g was obtained. The obtained polymer corresponds to formula (1-3). The weight average molecular weight Mw measured by GPC in terms of polystyrene was 4,600, and the polydispersity Mw / Mn was 3.16.

[0111] (Synthetic Example 4)

[0112] In a 100 mL two-necked flask, carbazole (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.00 g, 4-methylthiobenzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 7.28 g, propylene glycol monomethyl ether acetate 36.20 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.23 g were added. Then, heating was performed until 150°C, and stirring was performed for about 3.5 hours under reflux. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 24.71 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a resin of a powder 9.02 g was obtained. The obtained polymer corresponds to formula (1-4). The weight average molecular weight Mw measured by GPC in terms of polystyrene was 3,800, and the polydispersity Mw / Mn was 2.58.

[0113] (Synthetic Example 5)

[0114] In a 100 mL two-necked flask, carbazole (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.00 g, 4-nitrobenzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 7.24 g, propylene glycol monomethyl ether acetate 36.09 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.23 g were added. Then, heating was performed until 150°C, and stirring was performed for about 1.25 hours under reflux. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 24.63 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a resin of a powder 12.1 g was obtained. The obtained polymer corresponds to formula (1-5). The weight average molecular weight Mw determined by GPC in terms of polystyrene was 1,900, and the polydispersity Mw / Mn was 1.43.

[0115] (Synthetic Example 6)

[0116] In a 100 mL two-necked flask, carbazole (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.00 g, 4-nitrobenzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 7.24 g, propylene glycol monomethyl ether acetate 36.09 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.23 g were added. Then, heating was performed until 150°C, and stirring was performed for about 1.25 hours under reflux. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 24.63 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a resin of a powder 12.1 g was obtained. The obtained polymer corresponds to formula (1-5). The weight average molecular weight Mw determined by GPC in terms of polystyrene was 1,900, and the polydispersity Mw / Mn was 1.43.

[0117] (Synthetic Example 7)

[0118] In a 100 mL two-necked flask, carbazole (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.00 g, 4-nitrobenzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 7.24 g, propylene glycol monomethyl ether acetate 36.09 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.23 g were added. Then, heating was performed until 150°C, and stirring was performed for about 1.25 hours under reflux. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 24.63 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a resin of a powder 12.1 g was obtained. The obtained polymer corresponds to formula (1-5). The weight average molecular weight Mw determined by GPC in terms of polystyrene was 1,900, and the polydispersity Mw / Mn was 1.43.

[0119] (Synthetic Example 8)

[0120] In a 100 mL two-necked flask were placed carbazole (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.00 g, 4-(2-hydroxyethoxy)benzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.95 g, propylene glycol monomethyl ether acetate 43.68 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.78 g. Then, heating was performed until 150°C, and stirring was performed for about 2.5 hours under reflux. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 27.32 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powder of a resin 10.8 g was obtained. The obtained polymer corresponds to formula (1-8). The weight average molecular weight Mw measured by GPC was 3,400 in terms of polystyrene, and the polydispersity Mw / Mn was 1.85.

[0121] (Synthetic Example 9)

[0122] In a 100 mL two-necked flask were placed carbazole (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.00 g, 2,4,6-trimethylbenzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 7.10 g, propylene glycol monomethyl ether acetate 37.37 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.92 g. Then, heating was performed until 150°C, and stirring was performed for about 21.5 hours under reflux. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 22.09 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powder of a resin 9.20 g was obtained. The obtained polymer corresponds to formula (1-9). The weight average molecular weight Mw measured by GPC was 12,700 in terms of polystyrene, and the polydispersity Mw / Mn was 3.82.

[0123] (Synthetic Example 10)

[0124] In a 100 mL two-necked flask were placed diphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 7.04 g, p-tolylaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 5.00 g, propylene glycol monomethyl ether acetate 20.65 g, propylene glycol monomethyl ether 8.85 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.60 g. Then, heating was performed until 150°C, and stirring was performed for about 1.5 hours under reflux. After completion of the reaction, dilution was performed with cyclohexanone 18.07 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powder of a resin 8.11 g was obtained. The obtained polymer corresponds to formula (1-10). The weight average molecular weight Mw measured by GPC was 15,300 in terms of polystyrene, and the polydispersity Mw / Mn was 3.52.

[0125] (Synthetic Example 11)

[0126] In a 100 mL two-necked flask were placed diphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 9.02 g, p-formylbenzoic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.00 g, propylene glycol monomethyl ether acetate 28.63 g, propylene glycol monomethyl ether 12.27 g, and methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.51 g. Then, heating was performed until 150°C, and stirring was performed for about 30 minutes under reflux. After completion of the reaction, dilution was performed with cyclohexanone 26.66 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powdery resin 10.6 g was obtained. The obtained polymer corresponds to formula (1-11). The weight average molecular weight Mw measured by GPC in terms of polystyrene was 82,200, and the polydispersity Mw / Mn was 5.57.

[0127] (Synthetic Example 12)

[0128] In a 100 mL two-necked flask were placed diphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.90 g, 4-methylthiobenzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.00 g, propylene glycol monomethyl ether acetate 28.43 g, propylene glycol monomethyl ether 12.28 g, and methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.51 g. Then, heating was performed until 150°C, and stirring was performed for about 1 hour under reflux. After completion of the reaction, dilution was performed with cyclohexanone 26.48 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powdery resin 10.7 g was obtained. The obtained polymer corresponds to formula (1-12). The weight average molecular weight Mw measured by GPC in terms of polystyrene was 6,300, and the polydispersity Mw / Mn was 2.90.

[0129] (Synthetic Example 13)

[0130] In a 100 mL two-necked flask were placed diphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.95 g, 4-nitrobenzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.00 g, propylene glycol monomethyl ether acetate 40.74 g, and methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.51 g. Then, heating was performed until 150°C, and stirring was performed for about 15 minutes under reflux. After completion of the reaction, dilution was performed with cyclohexanone 26.56 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powdery resin 9.54 g was obtained. The obtained polymer corresponds to formula (1-13). The weight average molecular weight Mw measured by GPC in terms of polystyrene was 2,500, and the polydispersity Mw / Mn was 1.95.

[0131] (Synthetic Example 14)

[0132] In a 100 mL two-necked flask was placed diphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 6.80 g, 4-trifluoromethylbenzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 7.00 g, propylene glycol monomethyl ether acetate 23.49 g, propylene glycol monomethyl ether 10.07 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.58 g. Then, heating was performed until 150°C, and stirring was performed for about 1.5 hours. After completion of the reaction, dilution was performed with cyclohexanone 21.07 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powder of resin 4.76 g was obtained. The obtained polymer corresponds to formula (1-14). The weight average molecular weight Mw determined by GPC in terms of polystyrene was 103,000, and the polydispersity Mw / Mn was 2.32.

[0133] (Synthetic Example 15)

[0134] In a 100 mL two-necked flask was placed 1,1,1-tris(4-hydroxyphenyl)ethane (manufactured by Tokyo Chemical Industry Co., Ltd.) 12.00 g, p-tolualdehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 4.71 g, propylene glycol monomethyl ether acetate 20.81 g, propylene glycol monomethyl ether 20.81 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 1.13 g. Then, heating was performed until 150°C, and stirring was performed for about 24 hours. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 24.08 g. The solution was added dropwise to a methanol / water = 60 / 40 (vol% / vol%) solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powder of resin 7.03 g was obtained. The obtained polymer corresponds to formula (1-15). The weight average molecular weight Mw determined by GPC in terms of polystyrene was 2,100, and the polydispersity Mw / Mn was 1.61.

[0135] (Synthetic Example 16)

[0136] In a 100 mL two-necked flask was placed 1,1,1-tris(4-hydroxyphenyl)ethane (manufactured by Tokyo Chemical Industry Co., Ltd.) 10.20 g, p-formylbenzoic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 5.00 g, propylene glycol monomethyl ether acetate 18.30 g, propylene glycol monomethyl ether 18.30 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.48 g. Then, heating was performed until 150°C, and stirring was performed under reflux for about 24 hours. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 23.74 g. The solution was added dropwise to methanol / water = 50 / 50 (vol% / vol%) to perform reprecipitation. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powdery resin 7.84 g was obtained. The obtained polymer corresponds to formula (1-16). The weight average molecular weight Mw measured by GPC in terms of polystyrene was 4,000, and the polydispersity Mw / Mn was 2.17.

[0137] (Synthetic Example 17)

[0138] In a 100 mL two-necked flask was placed 1,1,1-tris(4-hydroxyphenyl)ethane (manufactured by Tokyo Chemical Industry Co., Ltd.) 12.00 g, 4-methylthiobenzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 5.96 g, propylene glycol monomethyl ether acetate 29.95 g, propylene glycol monomethyl ether 12.83 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.38 g. Then, heating was performed until 150°C, and stirring was performed under reflux for about 44 hours. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 28.67 g. The solution was added dropwise to methanol / water = 50 / 50 (vol% / vol%) to perform reprecipitation. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powdery resin 11.9 g was obtained. The obtained polymer corresponds to formula (1-17). The weight average molecular weight Mw measured by GPC in terms of polystyrene was 2,000, and the polydispersity Mw / Mn was 1.73.

[0139] (Synthetic Example 18)

[0140] In a 100 mL two-necked flask was placed 1,1,1-tris(4-hydroxyphenyl)ethane (manufactured by Tokyo Chemical Industry Co., Ltd.) 10.14 g, 4-nitrobenzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 5.00 g, propylene glycol monomethyl ether acetate 18.22 g, propylene glycol monomethyl ether 18.22 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.48 g. Then, heating was performed until 150°C, and stirring was performed under reflux for about 24 hours. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 23.64 g. The solution was added dropwise to methanol / water = 50 / 50 (vol% / vol%) to perform reprecipitation. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powdery resin 11.6 g was obtained. The obtained polymer corresponds to formula (1-18). The weight average molecular weight Mw determined by GPC in terms of polystyrene was 4,300, and the polydispersity Mw / Mn was 2.14.

[0141] (Synthetic Example 19)

[0142] In a 100 mL two-necked flask was placed 1,1,1-tris(4-hydroxyphenyl)ethane (manufactured by Tokyo Chemical Industry Co., Ltd.) 12.00 g, 4-trifluoromethylbenzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 6.82 g, propylene glycol monomethyl ether acetate 23.27 g, propylene glycol monomethyl ether 23.27 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 1.13 g. Then, heating was performed until 150°C, and stirring was performed under reflux for about 5 hours. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 27.60 g. The solution was added dropwise to methanol / water = 50 / 50 (vol% / vol%) to perform reprecipitation. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powdery resin 11.1 g was obtained. The obtained polymer corresponds to formula (1-19). The weight average molecular weight Mw determined by GPC in terms of polystyrene was 4,000, and the polydispersity Mw / Mn was 1.53.

[0143] (Synthetic Example 20)

[0144] In a 100 mL two-necked flask was placed N-phenylanthranilic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 10.05 g, benzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 5.00 g, propylene glycol monomethyl ether acetate 18.35 g, propylene glycol monomethyl ether 18.35 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.68 g. Then, heating was performed until 150°C, and stirring was performed for about 2 hours under reflux. After completion of the reaction, dilution was performed with cyclohexanone 22.81 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powdery resin 7.81 g was obtained. The obtained polymer corresponds to formula (1-20). The weight average molecular weight Mw was 6,300, and the polydispersity Mw / Mn was 1.78, which were determined by GPC in terms of polystyrene.

[0145] (Synthetic Example 21)

[0146] In a 100 mL two-necked flask was placed 3-methyldiphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 9.50 g, benzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 5.50 g, propylene glycol monomethyl ether acetate 18.37 g, propylene glycol monomethyl ether 18.37 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.75 g. Then, heating was performed until 150°C, and stirring was performed for about 45 minutes under reflux. After completion of the reaction, dilution was performed with cyclohexanone 22.51 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powdery resin 11.5 g was obtained. The obtained polymer corresponds to formula (1-21). The weight average molecular weight Mw was 52,700, and the polydispersity Mw / Mn was 8.86, which were determined by GPC in terms of polystyrene.

[0147] (Comparative Synthetic Example 1)

[0148] In a 100 mL two-necked flask was placed carbazole (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.00 g, benzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 5.08 g, propylene glycol monomethyl ether acetate 32.36 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.92 g. Then, heating was performed until 150°C, and stirring was performed for about 1.5 hours under reflux. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 23.43 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powdery resin 8.92 g was obtained. The obtained polymer corresponds to formula (2-1). The weight average molecular weight Mw was 32,200, and the polydispersity Mw / Mn was 2.14, which were determined by GPC in terms of polystyrene.

[0149]

[0150] (Comparative Synthesis Example 2)

[0151] In a 100 mL two-necked flask was placed diphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.77 g, benzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 5.50 g, propylene glycol monomethyl ether acetate 24.53 g, propylene glycol monomethyl ether 10.51 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.75 g. Then, heating was performed until 150°C, and stirring was performed for about 15 minutes under reflux. After the completion of the reaction, dilution was performed with cyclohexanone 92.65 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powder resin 8.58 g was obtained. The obtained polymer corresponds to formula (2-2). The weight average molecular weight Mw measured by GPC in terms of polystyrene was 8,400, and the polydispersity Mw / Mn was 2.38.

[0152]

[0153] (Comparative Synthesis Example 3)

[0154] In a 100 mL two-necked flask was placed 1,1,1-tris(4-hydroxyphenyl)ethane (manufactured by Tokyo Chemical Industry Co., Ltd.) 12.00 g, benzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 4.16 g, propylene glycol monomethyl ether acetate 19.51 g, propylene glycol monomethyl ether 19.51 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.56 g. Then, heating was performed until 150°C, and stirring was performed for about 19 hours under reflux. After the completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 24.08 g. The solution was added dropwise to a methanol / water = 50 / 50 (vol% / vol%) solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powder resin 11.0 g was obtained. The obtained polymer corresponds to formula (2-3). The weight average molecular weight Mw measured by GPC in terms of polystyrene was 4,600, and the polydispersity Mw / Mn was 1.64.

[0155]

[0156] (Comparative Synthesis Example 4)

[0157] In a 100 mL two-necked flask was placed carbazole (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.00 g, 4-tert-butylbenzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 7.77 g, propylene glycol monomethyl ether acetate 38.94 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.92 g. Then, heating was performed until 150°C, and stirring was performed for about 1.5 hours under reflux. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 23.21 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powder of resin 13.3 g was obtained. The obtained polymer corresponds to formula (2-4). The weight average molecular weight Mw determined by GPC in terms of polystyrene was 25,800, and the polydispersity Mw / Mn was 4.44.

[0158]

[0159] (Comparative Synthesis Example 5)

[0160] In a 100 mL two-necked flask was placed diphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.34 g, 4-tert-butylbenzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 8.34 g, propylene glycol monomethyl ether acetate 39.24 g, methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.47 g. Then, heating was performed until 150°C, and stirring was performed for about 3 hours under reflux. After completion of the reaction, dilution was performed with propylene glycol monomethyl ether acetate 25.66 g. The solution was added dropwise to a methanol solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C for one night. Thus, a powder of resin 9.65 g was obtained. The obtained polymer corresponds to formula (2-5). The weight average molecular weight Mw determined by GPC in terms of polystyrene was 6,300, and the polydispersity Mw / Mn was 2.03.

[0161]

[0162] (Comparative Synthesis Example 6)

[0163] In a 100 mL two-necked flask, 1,1,1-tris(4-hydroxyphenyl)ethane (manufactured by Tokyo Chemical Industry Co., Ltd.) 10.39 g, 4-tert-butylbenzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) 5.50 g, propylene glycol monomethyl ether acetate 19.10 g, propylene glycol monomethyl ether 19.10 g, and methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.49 g were charged. Then, the mixture was heated until 150°C and stirred under reflux for about 24 hours. After the completion of the reaction, the mixture was diluted with propylene glycol monomethyl ether acetate 24.85 g. The solution was added dropwise to a methanol / water = 50 / 50 (vol% / vol%) solution, and reprecipitation was performed. The obtained precipitate was suction-filtered, and the filtrate was dried under reduced pressure at 60°C overnight. Thus, a powdery resin 10.3 g was obtained. The obtained polymer corresponds to formula (2-6). The weight average molecular weight Mw determined by GPC in terms of polystyrene was 2,000, and the polydispersity Mw / Mn was 1.97.

[0164]

[0165] After each of the resins of the above Synthesis Examples and Comparative Synthesis Examples was dissolved in a solvent, cation exchange resin (product name: Dowex® 550A, manufactured by Muromachi Technos Co., Ltd.) and anion exchange resin (product name: Amberlite® 15JWET, manufactured by Organo Co., Ltd.) were added, and ion exchange treatment was performed at room temperature for 4 hours. After the ion exchange resins were separated, purified resins were obtained.

[0166] (Example 1)

[0167] With respect to 1.0 g of the resin obtained in Synthesis Example 1, 0.001 g of Megafack R-40 as a surfactant was mixed, and the mixture was dissolved in propylene glycol monomethyl ether acetate 5.66 g and propylene glycol monomethyl ether 2.42 g. The solution was filtered using a polytetrafluoroethylene microfilter having a pore size of 0.02 μm, and a solution of a composition for forming a lower layer film of a resist used in a multi-layer film photolithography process was prepared.

[0168] Examples 2 to 21 and Comparative Examples 1 to 6 were also carried out in the same manner.

[0169] In addition, the amounts of the polymer, the surfactant, and the solvent were as described in Tables 1 to 3 below.

[0170] In the table, the number of the synthesis example of the used polymer is described, and the surfactant a = Megafack (trade name) R-40 manufactured by DIC Corporation, a fluorine-based surfactant, the solvent b = propylene glycol monomethyl ether acetate, the solvent c = propylene glycol monomethyl ether, the solvent d = cyclohexanone, and the content of the lower layer g is described.

[0171] Table 1

[0172]

[0173] Table 2

[0174]

[0175] Table 3

[0176]

[0177] (Dissolution test into resist solvent)

[0178] Solutions of the resist underlayer film-forming compositions prepared in Examples 1 to 21 and Comparative Examples 1 to 6 were applied to silicon wafers using a spin coater and fired on a hot plate at 400°C for 90 seconds to form resist underlayer films (film thickness 0.20 μm). These resist underlayer films were then immersed in ethyl lactate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and cyclohexanone, which serve as resist solvents. These resist underlayer films were insoluble in these solvents.

[0179] (Determination of film density)

[0180] The solutions of the resist underlayer film-forming compositions prepared in Examples 1 to 21 and Comparative Examples 1 to 6 were applied to silicon wafers using a spin coater and fired on a hot plate at 400°C for 90 seconds to form resist underlayer films (film thickness 0.20 μm). To determine the density of these resist underlayer films, an X-ray reflectivity analyzer (manufactured by Bruker) was used for evaluation. The results are shown in the table below.

[0181] Table 4

[0182]

[0183] Table 5

[0184]

[0185] (Determination of hardness and Young's modulus)

[0186] The solutions of the resist underlayer film-forming compositions prepared in Examples 1 to 21 and Comparative Examples 1 to 6 were applied to silicon wafers using a spin coater and fired on a hot plate at 400°C for 90 seconds to form resist underlayer films (film thickness 0.20 μm). To determine the hardness and Young's modulus of these resist underlayer films, an indentation tester (manufactured by Toyo Technics) was used to evaluate the films. The results are shown in the table below.

[0187] Table 6

[0188]

[0189] Table 7

[0190]

[0191] (Twist resistance evaluation)

[0192] A solution of each resist underlayer film-forming composition prepared in Examples 2, 4, 9 and Comparative Examples 4 to 6 was coated on a silicon wafer with a silicon oxide film using a spin coater. A resist underlayer film (film thickness 200 nm) was formed by baking on a hot plate at 400°C for 90 seconds. A solution of a silicon hard mask-forming composition was coated on the resist underlayer film, and a silicon hard mask layer (film thickness 30 nm) was formed by baking at 240°C for 1 minute. A resist solution was coated thereon, and a resist layer (film thickness 150 nm) was formed by baking at 100°C for 1 minute. Exposure was performed using a mask at a wavelength of 193 nm, and post-exposure bake (PEB) (105°C, 1 minute) was performed, followed by development to obtain a resist pattern. Then, dry etching was performed with a fluorine-based gas (composition: CF4) to transfer the resist pattern to the hard mask. Then, dry etching was performed with an oxygen-based gas (composition: O2) to transfer the resist pattern to the resist underlayer film of the present application. Then, dry etching was performed with a fluorine-based gas (composition: C4F8) to perform removal of the silicon oxide film on the silicon wafer. The shape of each pattern at this time was observed.

[0193] As the pattern width becomes narrower, the bending of such irregular patterns is apt to occur, and the pattern width at which the bending begins to occur was observed using an electron microscope for the above-described process using the resist underlayer film-forming composition of the above-described examples.

[0194] Since the substrate cannot be processed based on the faithful pattern due to the occurrence of the bending, it is necessary to process the substrate by the pattern width just before the bending occurs (critical pattern width). The narrower the value of the critical pattern width at which the bending begins to occur, the more the fine substrate processing can be performed.

[0195] A length-measuring scanning-type electron microscope (manufactured by Hitachi, Ltd.) was used for the measurement of the resolution. The measurement results are shown in the following table.

[0196] Table 8

[0197]

[0198] If Examples 2, 4 and 9 are compared with Comparative Example 4, the Examples 2, 4 and 9 in which two or more specific chemical groups (a), (b) and (c) are substituted on the benzene ring constituting the carbazole novolak resin are higher in film density, hardness and Young's modulus than Comparative Example 4, the minimum pattern size at which they are proportionally twisted is small, and thus the twist resistance is improved, and the etching resistance is also improved.

[0199] Furthermore, if comparing Comparative Examples 4 to 6, the carbazole novolak resin (Comparative Example 4) has higher film density, hardness, and Young's modulus than the diphenylamine novolak resin (Comparative Example 5) and the polyhydric phenol novolak resin (Comparative Example 6), and the minimum pattern size that is distorted in proportion to the values thereof is almost the same or smaller. With respect to the carbazole novolak resin (Comparative Example 4), there is the above tendency, and with respect to the diphenylamine novolak resin (Comparative Example 5) and the polyhydric phenol novolak resin (Comparative Example 6) as well, by substituting the benzene ring constituting the novolak resin with two or more of the above specific chemical groups (a), (b), and (c), the film density, hardness, and Young's modulus are increased, and the minimum pattern size that is distorted in proportion to the values thereof is decreased, the distortion resistance is increased, and the etching resistance is also increased.

[0200] According to the above, by substituting the benzene ring with two or more of the above specific chemical groups, the film density, hardness, and Young's modulus are increased, and the distortion resistance and etching resistance are increased in conjunction therewith. This can be considered to be a common effect not only for a resist underlayer film using a carbazole novolak resin, but also for a resist underlayer film using a novolak resin.

[0201] Industrial applicability

[0202] With the present application, a resist underlayer film forming composition for forming a resist underlayer film having high film density, hardness, Young's modulus, and distortion resistance (high bending resistance), and thus high etching resistance, can be obtained.

Claims

1. A method for manufacturing a semiconductor device, comprising the steps of: forming a resist underlayer film from a resist underlayer film-forming composition; forming a resist film on the resist underlayer film; forming a resist pattern by irradiating with light or electron beams and developing the resist pattern; etching the underlayer film using the formed resist pattern; and processing a semiconductor substrate using the patterned underlayer film. The resist underlayer film-forming composition comprises a novolac resin having a repeating unit structure represented by the following formula (1): In formula (1), group A and group B are each independently an organic group having an aromatic ring, a condensed aromatic ring, or a condensed aromatic heterocycle, and the organic group has the following structure: hydrogen atoms bonded to carbon atoms on the aromatic ring, the condensed aromatic ring, or the condensed aromatic heterocycle in group A or group B or in both groups are substituted with two or more monovalent or divalent chemical groups of the same or different types selected from the following chemical groups (a) and (b), respectively; the chemical group (a) is a methyl group, a sulfide group, or a combination thereof; the chemical group (b) is an amino group, a carboxyl group, an alkyl carboxylate group, a nitro group, a hydroxyl group, an ether group, or a combination thereof; when the chemical group is divalent, the rings may be bonded to each other via the chemical group or condensed together with the chemical group; In formula (1), group A is an organic group containing benzene, naphthalene, carbazole, diphenylamine or trihydroxyphenylethane, In formula (1), group B is an organic group having benzene or naphthalene, The amino group contained in carbazole and diphenylamine corresponds to the chemical group (b) above, and is a structure in which two hydrogen atoms of the benzene ring are replaced by secondary amino groups. When the chemical group (a) is a methyl group, the formula (1) is the following formula (1-9) or formula (1-10), Furthermore, in formula (1), excluding formula (1-1), 2. The method for manufacturing a semiconductor device according to claim 1, wherein the novolac resin represented by formula (1) has the following structure: a structure obtained by replacing hydrogen atoms of an aromatic ring, a condensed aromatic ring, or a condensed aromatic heterocycle with two or more chemical groups selected from the group consisting of chemical group (a), chemical group (b), and a combination of chemical group (a) and chemical group (b).

3. The method for manufacturing a semiconductor device according to claim 1, wherein the novolac resin represented by formula (1) has the following structure: at least one hydrogen atom bound to a carbon atom on an aromatic ring, a condensed aromatic ring, or a condensed aromatic heterocycle in both groups A and B is replaced by two chemical groups of the same or different types selected from chemical group (b), or by two chemical groups selected from chemical group (a) and chemical group (b), respectively, thereby introducing a structure of two chemical groups into the unit structure. 4 . The method for manufacturing a semiconductor device according to claim 1 , wherein the resist underlayer film-forming composition further contains a cross-linking agent. 5 . The method for manufacturing a semiconductor device according to claim 1 , wherein the resist underlayer film-forming composition further contains an acid and / or an acid generator.

6. The method for manufacturing a semiconductor device according to claim 1, wherein the formula (1) is represented by the following formula:

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