Lithography film-forming composition, lithography underlayer film, and resist pattern forming method

Abstract

This lithography film-forming composition contains a multi-branched type tellurium-containing resin obtained through an addition reaction of: at least one aromatic compound selected from the group consisting of polyphenyl compounds and fused polycyclic aromatic hydrocarbon compounds; and at least one tellurium compound selected from the group consisting of tellurium tetrachloride and tetraalkoxy telluriums. The lithography film-forming composition contains a multi-branched type tellurium-containing resin having high solubility with respect to solvents, excellent film-forming characteristics, and high heat resistance.

Description

Lithography film-forming composition, lithography underlayer film, and method for forming a resist pattern

[0001] The present invention relates to a lithography film-forming composition, a lithography underlayer film, and a method for forming a resist pattern.

[0002] In the manufacture of semiconductor devices, microfabrication is performed by lithography using photoresist materials. However, in recent years, with the increasing integration and speed of LSIs (large-scale integrated circuits), further miniaturization using pattern rules is required. Conventional resist materials have been polymer-based resist materials capable of forming amorphous thin films. Examples of such materials include polymer-based resist materials such as polymethyl methacrylate, polyhydroxystyrene or polyalkyl methacrylate having an acid-dissociable group. Therefore, lithography materials that can accommodate further miniaturization of patterns are being developed. For example, Patent Document 1 discloses a lithography material containing a tellurium-containing compound or tellurium-containing resin as a resist material that reduces film defects, has good storage stability, and is highly sensitive.

[0003] International Publication No. 2017 / 033943

[0004] Lithography materials are increasingly required to satisfy multiple performance requirements. For example, in semiconductor manufacturing processes, solubility in highly safe solvents used is required, while heat resistance is also required. Furthermore, the above properties and film-forming properties are also required at the same time. Therefore, there is a demand for lithography materials that can satisfy all of these performance requirements simultaneously. Therefore, an object of the present invention is to provide a lithography film-forming composition containing a hyperbranched tellurium-containing resin that has high solubility in solvents, excellent film-forming properties, and high heat resistance.

[0005] The present inventors have discovered that the above-mentioned problems can be solved by a lithography film-forming composition containing a multi-branched tellurium-containing resin obtained by an addition reaction of a specific aromatic compound with tellurium tetrachloride, and have thus completed the present invention.

[0006] That is, the present invention is as follows.<1> A lithographic film-forming composition containing a multi-branched tellurium-containing resin obtained by an addition reaction between at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds and at least one tellurium compound selected from the group consisting of tellurium tetrachloride and tetraalkoxytellurium.<2> The lithographic film-forming composition according to <1> above, containing a multi-branched tellurium-containing resin obtained by an addition reaction between at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds and tellurium tetrachloride.<3> The lithographic film-forming composition according to <1> or <2> above, wherein the aromatic compound is at least one selected from the group consisting of triphenylmethane, tetraphenylmethane, anthracene, perylene, phenanthrene, and naphthalene.<4> The lithographic film-forming composition according to any one of <1> to <3> above, wherein the aromatic compound includes a compound represented by the following formula (1): (wherein R represents a hydrogen atom, a methyl group, or a phenyl group.) <5> The lithographic film-forming composition according to any one of <1> to <4>, wherein the multi-branched tellurium-containing resin contains at least one structural unit selected from the group consisting of a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), and a structural unit represented by the following formula (4): (wherein R represents a hydrogen atom, a methyl group, or a phenyl group.) <6> The lithographic film-forming composition according to any one of <1> to <5> above, further containing a solvent. <7> The lithographic film-forming composition according to any one of <1> to <6> above, further containing at least one selected from the group consisting of an acid generator and an acid crosslinker. <8> The lithographic film-forming composition according to any one of <1> to <7> above, which is a lithographic underlayer film-forming composition. <9> A lithographic underlayer film formed from the lithographic film-forming composition according to any one of <1> to <8> above. <10> A method for forming a resist pattern, using the lithographic film-forming composition according to any one of <1> to <8> above.

[0007] According to the present invention, it is possible to provide a lithography film-forming composition containing a hyperbranched tellurium-containing resin that has high solubility in solvents, excellent film-forming properties, and high heat resistance.

[0008] [Lithography Film-Forming Composition] The lithography film-forming composition of the present invention is a lithography film-forming composition containing a multi-branched tellurium-containing resin obtained by addition reaction of at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds with at least one tellurium compound selected from the group consisting of tellurium tetrachloride and tetraalkoxytellurium, and is preferably a lithography film-forming composition containing a multi-branched tellurium-containing resin obtained by addition reaction of at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds with tellurium tetrachloride. That is, the lithography film-forming composition of the present invention is a lithography film-forming composition containing a multi-branched tellurium-containing resin, wherein the multi-branched tellurium-containing resin is a resin obtained by an addition reaction of at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds with at least one tellurium compound selected from the group consisting of tellurium tetrachloride and tetraalkoxytellurium compounds, and is preferably a lithography film-forming composition containing a multi-branched tellurium-containing resin, wherein the multi-branched tellurium-containing resin is a resin obtained by an addition reaction of at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds with tellurium tetrachloride.

[0009] <Multi-branched tellurium-containing resin> The multi-branched tellurium-containing resin contained in the lithography film-forming composition of the present invention is a multi-branched tellurium-containing resin obtained by an addition reaction of at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds with at least one tellurium compound selected from the group consisting of tellurium tetrachloride and tetraalkoxytellurium, and is preferably a multi-branched tellurium-containing resin obtained by an addition reaction of at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds with tellurium tetrachloride. Such multi-branched tellurium-containing resins have high solubility in solvents, excellent film-forming properties, and high heat resistance, making them suitable for use as a component of lithography film-forming compositions. The hyperbranched tellurium-containing resin has a core-shell structure, and properties such as solubility in a solvent are mainly contributed by the shell structure, whereas the sensitivity to EUV exposure, which is an advanced lithography technology, for example, is contributed by the overall elemental composition including the shell portion. Therefore, the hyperbranched tellurium-containing resin can have all the necessary properties as a component of a lithography film-forming composition.

[0010] (Aromatic Compound) In the present invention, the aromatic compound used as a raw material for the multi-branched tellurium-containing resin is at least one selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds. The aromatic compound preferably uses at least one compound containing three or more aromatic rings in one molecule. That is, the aromatic compound preferably contains at least one compound containing three or more aromatic rings in one molecule. When the aromatic compound contains a compound containing three or more aromatic rings in one molecule, a tellurium-containing resin with a multi-branched structure can be obtained.

[0011] The polyphenyl compound is a compound containing two or more phenyl groups in one molecule, preferably a compound containing three or more phenyl groups in one molecule, more preferably a compound containing three or four phenyl groups in one molecule, and even more preferably a compound containing three phenyl groups in one molecule. The use of a compound containing three or more phenyl groups in one molecule is preferred because it allows a tellurium-containing resin with a multi-branched structure to be obtained. The polyphenyl compound preferably includes a compound represented by the following formula (1): (In the formula, R is a hydrogen atom, a methyl group, or a phenyl group.)

[0012] In formula (1), R is a hydrogen atom, a methyl group, or a phenyl group, preferably a hydrogen atom. Preferred examples of the compound represented by formula (1) include triphenylmethane and tetraphenylmethane, more preferably at least one selected from the group consisting of triphenylmethane and tetraphenylmethane, and even more preferably triphenylmethane.

[0013] The polyphenyl compound is preferably a compound containing three or more phenyl groups in one molecule, but may also include a compound containing two phenyl groups in one molecule. Examples of the compound containing two phenyl groups in one molecule include a compound represented by the following formula (5) and a compound represented by the following formula (6). (In the formula, X is an oxygen atom or a sulfur atom.)

[0014] In formula (6), X is an oxygen atom or a sulfur atom, and is preferably an oxygen atom.

[0015] The condensed polycyclic aromatic hydrocarbon compound is a compound containing a structure in which two or more aromatic rings are condensed in one molecule, preferably a compound containing a structure in which three or more aromatic rings are condensed in one molecule, and more preferably a compound containing a structure in which three or four aromatic rings are condensed in one molecule. A compound containing a structure in which two or more aromatic rings are condensed is preferably used because a tellurium-containing resin having a multi-branched structure can be obtained. A compound containing a structure in which three or more aromatic rings are condensed is more preferably used because a tellurium-containing resin having a multi-branched structure can also be obtained. Preferred condensed polycyclic aromatic hydrocarbon compounds include anthracene (a compound containing a structure in which three aromatic rings are condensed), perylene (a compound containing a structure in which five aromatic rings are condensed), phenanthrene (a compound containing a structure in which three aromatic rings are condensed), and naphthalene (a compound containing a structure in which two aromatic rings are condensed), and more preferably at least one selected from the group consisting of anthracene, perylene, phenanthrene, and naphthalene.

[0016] As described above, the aromatic compound is preferably at least one selected from the group consisting of triphenylmethane, tetraphenylmethane, anthracene, perylene, phenanthrene, and naphthalene, more preferably at least one selected from the group consisting of triphenylmethane and tetraphenylmethane, and even more preferably triphenylmethane.

[0017] (Tellurium Compound) In the present invention, the tellurium compound used as a raw material for the multi-branched tellurium-containing resin is at least one tellurium compound selected from the group consisting of tellurium tetrachloride and tetraalkoxytellurium, preferably tellurium tetrachloride. Examples of tetraalkoxytellurium include tetramethoxytellurium, tetraethoxytellurium, and tetraisopropoxytellurium. From the viewpoint of availability, at least one selected from the group consisting of tetraethoxytellurium and tetraisopropoxytellurium is preferred, more preferably tetraethoxytellurium.

[0018] <Structure of Hyperbranched Tellurium-Containing Resin> The hyperbranched tellurium-containing resin contained in the lithographic film-forming composition of the present invention preferably contains at least one structural unit selected from the group consisting of a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), and a structural unit represented by the following formula (4). When the hyperbranched tellurium-containing resin contains such a structural unit, it has higher solubility in solvents, better film-forming properties, and higher heat resistance, making it more suitable for use as a component of a lithographic film-forming composition. (In the formula, R is a hydrogen atom, a methyl group, or a phenyl group.)

[0019] In formula (2), R is a hydrogen atom, a methyl group, or a phenyl group, preferably a hydrogen atom. In formula (3), R is a hydrogen atom, a methyl group, or a phenyl group, preferably a hydrogen atom. In formula (4), R is a hydrogen atom, a methyl group, or a phenyl group, preferably a hydrogen atom.

[0020] <Characteristics of the Hyperbranched Tellurium-Containing Resin> The number-average molecular weight of the hyperbranched tellurium-containing resin contained in the lithography film-forming composition of the present invention is preferably 1,000 to 10,000, more preferably 1,500 to 8,000, even more preferably 1,500 to 5,000, and even more preferably 2,000 to 5,000. Having a number-average molecular weight within the above range results in high solubility in solvents, excellent film-forming properties, and high heat resistance. From the viewpoint of heat resistance in particular, the number-average molecular weight of the hyperbranched tellurium-containing resin is more preferably 2,000 to 10,000, even more preferably 3,000 to 9,000, and even more preferably 5,000 to 9,000. The molecular weight distribution (Mw / Mn) of the hyperbranched tellurium-containing resin is preferably 1.5 to 10.0, more preferably 1.5 to 7.0, even more preferably 1.5 to 4.0, and even more preferably 1.5 to 2.5. When the molecular weight distribution is in the above range, the polymer has high solubility in solvents, excellent film-forming properties, and high heat resistance.

[0021] Furthermore, the hyperbranched tellurium-containing resin has a high absorption ability for soft X-rays and X-rays with wavelengths of 3 to 20 nm, and therefore has a high absorption ability for EUV light within the wavelength range. Therefore, the hyperbranched tellurium-containing resin can be suitably used, for example, in lithography film-forming compositions using EUV as exposure light for cutting-edge microfabrication.

[0022] <Method for producing a hyperbranched tellurium-containing resin> The hyperbranched tellurium-containing resin contained in the lithographic film-forming composition of the present invention may be produced by any method, as long as it is obtained by an addition reaction of at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds with at least one tellurium compound selected from the group consisting of tellurium tetrachloride and tetraalkoxytellurium. Furthermore, the hyperbranched tellurium-containing resin is preferably produced by an addition reaction of at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds with tellurium tetrachloride. Although the method for producing the hyperbranched tellurium-containing resin is not limited, the following method is preferred.

[0023] Specifically, it is preferable to obtain the resin by addition reaction of the aromatic compound and the tellurium compound in the presence of an acid catalyst such as aluminum chloride (AlCl3). It is even more preferable to obtain the resin by addition reaction of the aromatic compound and tellurium tetrachloride in the presence of an acid catalyst such as aluminum chloride (AlCl3). An example using tellurium tetrachloride is shown below. The amounts of the aromatic compound and tellurium tetrachloride used may be adjusted depending on the properties required for the resin, such as molecular weight, but are preferably determined based on the molar ratio of the aromatic rings of the aromatic compound to the tellurium atoms of the tellurium tetrachloride. The molar ratio of the aromatic rings of the aromatic compound to the tellurium atoms of the tellurium tetrachloride [aromatic rings / tellurium atoms] is preferably 50 / 50 to 95 / 5, more preferably 60 / 40 to 95 / 5, even more preferably 70 / 30 to 95 / 5, and even more preferably 80 / 20 to 92 / 8 from the viewpoint of obtaining a high molecular weight polymer. Furthermore, when a polyphenyl compound is used as the aromatic compound, the molar ratio of phenyl groups of the polyphenyl compound to tellurium atoms of tellurium tetrachloride [phenyl groups / tellurium atoms] is preferably 50 / 50 to 95 / 5, more preferably 60 / 40 to 95 / 5, even more preferably 70 / 30 to 95 / 5, and from the viewpoint of obtaining a high molecular weight product, even more preferably 80 / 20 to 92 / 8. When a compound represented by the formula (1) is used as the polyphenyl compound, the molar ratio of the compound represented by the formula (1) to tellurium tetrachloride [formula (1) / tellurium tetrachloride] is preferably 30 / 70 to 80 / 20, more preferably 40 / 60 to 80 / 20, even more preferably 50 / 50 to 80 / 20, and from the viewpoint of obtaining a high molecular weight product, even more preferably 60 / 40 to 80 / 20. When triphenylmethane, which is suitable as the polyphenyl compound, is used, the molar ratio of triphenylmethane to tellurium tetrachloride [triphenylmethane / tellurium tetrachloride] is preferably 30 / 70 to 80 / 20, more preferably 40 / 60 to 80 / 20, even more preferably 50 / 50 to 80 / 20, and from the viewpoint of obtaining a high molecular weight compound, still more preferably 60 / 40 to 80 / 20.

[0024] The reaction temperature is preferably 0 to 100° C., more preferably 20 to 80° C., and even more preferably 30 to 70° C. The reaction time may be adjusted appropriately depending on the reaction temperature, the amount of catalyst, the reactivity of the raw materials, the target molecular weight, and the like, and is preferably 1 to 72 hours, more preferably 5 to 60 hours, and even more preferably 12 to 50 hours.

[0025] The reaction may be carried out in the presence of a solvent. A preferred solvent is one in which the resulting multi-branched tellurium-containing resin dissolves, more preferably a halogenated organic solvent, even more preferably a halogenated hydrocarbon, and even more preferably chloroform. The resulting multi-branched tellurium-containing resin is preferably purified by a conventional post-treatment. Specifically, the reaction mixture is preferably poured into an organic solvent in which the multi-branched tellurium-containing resin is insoluble, and the desired multi-branched tellurium-containing resin is recovered as a precipitate, thereby removing raw materials and by-products. Alternatively, the multi-branched tellurium-containing resin is preferably dissolved in an organic solvent in which the multi-branched tellurium-containing resin dissolves, and then washed with water or the like to remove catalysts and the like. When the multi-branched tellurium-containing resin is obtained as a solution in an organic solvent at the end of the reaction or purification treatment, it is preferably concentrated and dried to obtain the multi-branched tellurium-containing resin as a solid. The multi-branched tellurium-containing resin obtained in this manner has high solubility in solvents, excellent film-forming properties, and high heat resistance.

[0026] <Composition of Lithography Film-Forming Composition> The lithography film-forming composition of the present invention preferably further contains a solvent in addition to the multi-branched tellurium-containing resin. The lithography film-forming composition of the present invention preferably further contains at least one selected from the group consisting of an acid generator and an acid crosslinker, and more preferably contains both an acid generator and an acid crosslinker. The lithography film-forming composition of the present invention may further contain other optional components such as an acid or base compound, an acid diffusion controller, an organic polymer compound, a surfactant, a colorant, and a curing catalyst. From the viewpoints of coatability and quality stability, the content of the multi-branched tellurium-containing resin in the lithography film-forming composition of the present invention is preferably 0.1 to 70% by mass, more preferably 0.5 to 50% by mass, and even more preferably 3.0 to 40% by mass.

[0027]

[0039] (Solvent) From the viewpoint of improving film-forming properties, the lithography film-forming composition of the present invention preferably further contains a solvent. The solvent is not particularly limited as long as it dissolves the multi-branched tellurium-containing resin and the optional acid generator and other components, but the following solvents are preferred.Examples of the solvent include ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, and ethylene glycol mono-n-butyl ether acetate; ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate (PGMEA), propylene glycol mono-n-propyl ether acetate, and propylene glycol mono-n-butyl ether acetate; propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether (PGME) and propylene glycol monoethyl ether; lactate esters such as methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, and n-amyl lactate; methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, n-amyl acetate, and n-butyl acetate. aliphatic carboxylic acid esters such as methyl 3-hexyl, methyl propionate, and ethyl propionate; other esters such as methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, methyl 3-methoxy-2-methylpropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, butyl 3-methoxy-3-methylpropionate, butyl 3-methoxy-3-methylbutyrate, methyl acetoacetate, methyl pyruvate, and ethyl pyruvate; toluene, xylene ketones such as methyl ethyl ketone (MEK), 2-heptanone, 3-heptanone, 4-heptanone, cyclopentanone (CPN), and cyclohexanone (CHN); amides such as N,N-dimethylformamide (DMF), N-methylacetamide, N,N-dimethylacetamide (DMAc), and N-methylpyrrolidone; lactones such as γ-lactone; sulfoxides such as dimethyl sulfoxide (DMSO); halogenated hydrocarbons such as chloroform; and cyclic ethers such as tetrahydrofuran (THF).These solvents can be used alone or in combination of two or more. The solvent contained in the lithographic film-forming composition of the present invention is preferably a safe solvent, more preferably at least one selected from PGMEA, PGME, CHN, CPN, 2-heptanone, anisole, butyl acetate, ethyl propionate, ethyl lactate, THF, and DMF, and even more preferably at least one selected from PGMEA, PGME, CHN, THF, and DMF. From the viewpoints of solubility and film formation, the content of the solvent in the lithographic film-forming composition of the present invention is preferably 100 to 10,000 parts by mass, more preferably 200 to 8,000 parts by mass, and even more preferably 200 to 5,000 parts by mass, relative to 100 parts by mass of the total solid components (components excluding the solvent) of the lithographic film-forming composition.

[0028] (Acid Generator) In the lithographic film-forming composition of the present invention, the acid generator is preferably an acid generator that generates an acid directly or indirectly upon irradiation with any radiation selected from visible light, ultraviolet light, excimer laser, electron beam, extreme ultraviolet light (EUV), X-rays, and ion beams. In the lithographic film-forming composition of the present invention, the content of the acid generator is preferably 0.001 to 49 mass%, more preferably 1 to 40 mass%, even more preferably 3 to 30 mass%, still more preferably 5 to 25 mass%, and even more preferably 10 to 25 mass%, based on the total mass of the solid components (components excluding the solvent). By having the acid generator content within the above range, a pattern profile with high sensitivity and low edge roughness can be obtained. In the lithographic film-forming composition of the present invention, the acid generation method is not limited as long as an acid is generated in the system. Using an excimer laser as the radiation source instead of ultraviolet light such as g-line or i-line enables finer processing and is also advantageous as a high-energy beam. Further fine processing is possible using electron beams, extreme ultraviolet rays, X-rays, and ion beams.

[0029] The acid generator is not particularly limited, and examples thereof include the compounds disclosed in WO 2017 / 033943. The acid generator is preferably an acid generator having an aromatic ring, more preferably an acid generator having a sulfonate ion with an aryl group, and even more preferably at least one selected from the group consisting of diphenyltrimethylphenylsulfonium p-toluenesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoromethanesulfonate, ditertiarybutyldiphenyliodonium nonafluorobutanesulfonate, and pyridinium p-toluenesulfonate. Use of the acid generator can reduce line edge roughness.

[0030] The lithographic film-forming composition of the present invention preferably further contains a diazonaphthoquinone photoactive compound as an acid generator. The diazonaphthoquinone photoactive compound is a diazonaphthoquinone substance, including polymeric and non-polymeric diazonaphthoquinone photoactive compounds. It is not particularly limited as long as it is a diazonaphthoquinone substance generally used as a photosensitive component in positive resist compositions, and one or more types may be arbitrarily selected and used. Among these, from the viewpoints of low roughness and solubility, non-polymeric diazonaphthoquinone photoactive compounds are preferred, and low-molecular-weight compounds are more preferred. The molecular weight is preferably 1,500 or less, more preferably 1,200 or less, and even more preferably 1,000 or less. Preferred specific examples of such non-polymeric diazonaphthoquinone photoactive compounds include the non-polymeric diazonaphthoquinone photoactive compounds disclosed in WO 2016 / 158881. The acid generators can be used alone or in combination of two or more types.

[0031] (Acid Crosslinking Agent) The lithographic film-forming composition of the present invention preferably contains an acid crosslinking agent to increase the strength of the pattern, whether used as a negative resist material or a positive resist material. An acid crosslinking agent is a compound that can intramolecularly or intermolecularly crosslink a resin in the presence of an acid generated from an acid generator. Examples of such acid crosslinking agents include, but are not limited to, compounds having one or more crosslinkable groups capable of crosslinking a resin. Specific examples of crosslinkable groups include, but are not limited to, (i) hydroxyalkyl groups such as hydroxy (alkyl groups having 1 to 6 carbon atoms), alkoxy (alkyl groups having 1 to 6 carbon atoms), and acetoxy (alkyl groups having 1 to 6 carbon atoms), or groups derived therefrom; (ii) carbonyl groups such as formyl groups and carboxy (alkyl groups having 1 to 6 carbon atoms), or groups derived therefrom; (iii) dimethylaminomethyl groups, diethylaminomethyl groups, dimethylolaminomethyl groups, diethylaminomethyl groups, and the like. (iv) glycidyl group-containing groups such as a glycidyl ether group, a glycidyl ester group, and a glycidylamino group; (v) groups derived from aromatic groups such as allyloxy (an alkyl group having 1 to 6 carbon atoms) and aralkyloxy (an alkyl group having 1 to 6 carbon atoms) having 1 to 6 carbon atoms, such as a benzyloxymethyl group and a benzoyloxymethyl group; and (vi) polymerizable multiple bond-containing groups such as a vinyl group and an isopropenyl group. Examples of the crosslinkable group include hydroxyalkyl groups and alkoxyalkyl groups, and more preferably an alkoxymethyl group.

[0032] The acid crosslinking agent is not particularly limited, but examples thereof include (i) methylol group-containing compounds such as methylol group-containing melamine compounds, methylol group-containing benzoguanamine compounds, methylol group-containing urea compounds, methylol group-containing glycoluril compounds, and methylol group-containing phenol compounds; (ii) alkoxyalkyl group-containing compounds such as alkoxyalkyl group-containing melamine compounds, alkoxyalkyl group-containing benzoguanamine compounds, alkoxyalkyl group-containing urea compounds, alkoxyalkyl group-containing glycoluril compounds, and alkoxyalkyl group-containing phenol compounds; (iii) carboxymethyl group-containing compounds such as carboxymethyl group-containing melamine compounds, carboxymethyl group-containing benzoguanamine compounds, carboxymethyl group-containing urea compounds, carboxymethyl group-containing glycoluril compounds, and carboxymethyl group-containing phenol compounds; and (iv) epoxy compounds such as bisphenol A-based epoxy compounds, bisphenol F-based epoxy compounds, bisphenol S-based epoxy compounds, novolac resin-based epoxy compounds, resole resin-based epoxy compounds, and poly(hydroxystyrene)-based epoxy compounds. As the acid crosslinking agent, a compound having a phenolic hydroxyl group, or a compound or resin in which the crosslinkable group is introduced into an acidic functional group in an alkali-soluble resin to impart crosslinkability, can be used. In this case, the introduction rate of the crosslinkable group is not particularly limited, and is preferably 5 to 100 mol %, more preferably 10 to 60 mol %, and even more preferably 15 to 40 mol %, based on the total acidic functional groups in the compound having a phenolic hydroxyl group and the alkali-soluble resin. This range is preferable because it allows the crosslinking reaction to occur sufficiently, preventing a decrease in the residual film rate and preventing phenomena such as swelling and meandering of the pattern.

[0033] In the lithographic film-forming composition of the present invention, the acid crosslinker is preferably at least one selected from an alkoxyalkylated urea compound or a resin thereof, or an alkoxyalkylated glycoluril compound or a resin thereof (acid crosslinker (1)); a phenol derivative having 1 to 6 benzene rings in the molecule and having two or more hydroxyalkyl groups or alkoxyalkyl groups throughout the molecule, with the hydroxyalkyl groups or alkoxyalkyl groups bonded to any of the benzene rings (acid crosslinker (2)); and a compound having at least one α-hydroxyisopropyl group (acid crosslinker (3)). Examples include the compounds disclosed in WO 2017 / 033943. In the lithographic film-forming composition of the present invention, the content of the acid crosslinker is preferably 0.5 to 49% by mass, more preferably 0.5 to 40% by mass, even more preferably 1 to 30% by mass, and even more preferably 2 to 20% by mass, based on the total mass of the solid components (components excluding the solvent). A content of the acid crosslinker of 0.5% by mass or more is preferable because it improves the effect of suppressing the solubility of the resist film in an alkaline developer, thereby suppressing a decrease in the residual film rate and the occurrence of swelling or meandering of the pattern. Furthermore, a content of 49% by mass or less is preferable because it can suppress a decrease in the heat resistance of the resist. Furthermore, the contents of the acid crosslinker (1), acid crosslinker (2), and acid crosslinker (3) in the acid crosslinker are not particularly limited and can be selected depending on the type of substrate used when forming the resist pattern, etc.

[0034] (Acid Diffusion Controller) The lithographic film-forming composition of the present invention may further contain an acid diffusion controller, and preferably further contains an acid diffusion controller. The acid diffusion controller optionally contained in the lithographic film-forming composition of the present invention controls the diffusion of the acid generated from the acid generator upon irradiation in the resist film, thereby preventing undesirable chemical reactions in unexposed areas. This improves the storage stability of the lithographic film-forming composition, thereby improving resolution. In addition, it is possible to suppress changes in the line width of the resist pattern due to variations in the exposure time before and after radiation exposure, resulting in extremely excellent process stability.

[0035] Examples of the acid diffusion controller include radiolytic basic compounds such as nitrogen atom-containing basic compounds, basic sulfonium compounds, and basic iodonium compounds. Examples of the acid diffusion controller include the compounds disclosed in WO 2017 / 033943. The acid diffusion controller can be used alone or in combination of two or more.

[0036] In the lithographic film-forming composition of the present invention, the content of the acid diffusion controller is preferably 0.001 to 49% by mass, based on the total mass of the solid components (components excluding the solvent). From the viewpoint of preventing deterioration in sensitivity, developability of unexposed areas, etc., it is more preferably 0.01 to 10% by mass, even more preferably 0.01 to 5% by mass, and even more preferably 0.01 to 3% by mass. Within this range, it is possible to suppress deterioration in resolution and deterioration in the shape and dimensional fidelity of the resist pattern. Furthermore, deterioration in the shape of the upper layer of the resist pattern does not occur when a long waiting time is required between electron beam irradiation and post-irradiation heating.

[0037] <Lithography Underlayer Film-Forming Composition> The lithography film-forming composition of the present invention is a composition capable of forming a resist top layer film, a resist underlayer film, etc., and is preferably a lithography underlayer film-forming composition. The lithography film-forming composition of the present invention is preferably used as a lithography underlayer film-forming composition because the multi-branched tellurium-containing resin contained in the lithography film-forming composition has high solubility in solvents, excellent film-forming properties, and high heat resistance. That is, the lithography underlayer film-forming composition is a lithography film-forming composition containing the multi-branched tellurium-containing resin. The lithography underlayer film-forming composition can form a lithography underlayer film such as a resist underlayer film, and has high heat resistance and excellent solubility in solvents. Therefore, the rectangularity of the pattern is excellent. Furthermore, the excellent film-forming properties allow for the formation of a suitable resist pattern shape. Furthermore, the lithography underlayer film-forming composition can form a lithography underlayer film with high flatness.

[0038] The lithography underlayer film-forming composition can be suitably used, for example, in a multilayer resist method in which a resist underlayer film is further provided between an upper-layer resist (e.g., photoresist) and a hard mask or organic underlayer film. In such a multilayer resist method, for example, a resist underlayer film is formed on a substrate via an organic underlayer film or hard mask by a coating method or the like, and an upper-layer resist (e.g., photoresist, electron beam resist, EUV resist) is formed on the resist underlayer film. A resist pattern is then formed by exposure and development, and the resist underlayer film is dry-etched using the resist pattern to transfer the pattern. The organic underlayer film is then etched to transfer the pattern, and the substrate is processed using the organic underlayer film. That is, a lithography underlayer film (resist underlayer film) formed using the lithography film-forming composition of the present invention is less likely to intermix with the upper-layer resist, has heat resistance, and can form a good rectangular pattern. The lithography film-forming composition of the present invention can also be used in an embodiment in which multiple resist underlayer films are stacked. In this case, the position of the resist underlayer film formed using the lithography film-forming composition of the present invention (which layer it is stacked in) is not particularly limited, and it may be directly below the upper layer resist, may be the layer located closest to the substrate, or may be sandwiched between resist underlayer films.

[0039] When forming fine patterns, the resist film thickness tends to be thin to prevent pattern collapse. Dry etching for transferring a pattern to an underlying film by thinning the resist requires a higher etching rate than the overlying film to achieve pattern transfer. An organic underlayer film can be placed on a substrate, and the resist underlayer film of the present invention can be coated on top of that, and a resist film (organic resist film) can then be coated on top of that. For example, using the pattern-transferred resist underlayer film, the underlying organic underlayer film can be dry-etched with an oxygen-based gas to transfer the pattern to the organic underlayer film, and the pattern-transferred organic underlayer film can then be used to process the substrate using a halogen-containing gas. Furthermore, the resist underlayer film formed by the lithography film-forming composition of the present invention has high heat resistance and can be used even under high-temperature baking conditions. Furthermore, because of its relatively low molecular weight and low viscosity, it is easy to uniformly fill even substrates with steps (especially fine spaces or hole patterns, etc.), resulting in relatively advantageously improved planarization and filling properties.

[0040] [Lithography Underlayer Film] The hyperbranched tellurium-containing resin contained in the lithography film-forming composition of the present invention has high solubility in solvents, excellent film-forming properties, and high heat resistance. Therefore, it is preferable to form a lithography underlayer film using the lithography film-forming composition, which is a lithography underlayer film-forming composition. That is, the lithography underlayer film of the present invention is a lithography underlayer film formed from the lithography film-forming composition. The lithography underlayer film of the present invention can be suitably used as an underlayer (resist underlayer film) of a photoresist (upper layer) used in a multilayer resist method. The method for forming the lithography underlayer film of the present invention is not particularly limited as long as it is formed from the lithography film-forming composition of the present invention, and known methods can be applied. For example, a lithography underlayer film can be formed by applying the lithography film-forming composition to a substrate by a known coating or printing method such as spin coating or screen printing, and then removing the organic solvent. In particular, it is preferable to form a lithography underlayer film by the method described in the "step of forming an underlayer film" in the pattern formation method described below.

[0041] The lithography underlayer film of the present invention can be suitably used as an underlayer film of an EUV resist. A film formed from the lithography film-forming composition has excellent EUV absorption ability, and is therefore capable of exerting a sensitizing effect on an upper layer resist composition, contributing to improved sensitivity. The process of using the lithography underlayer film of the present invention as an underlayer film of an EUV resist can also be carried out by a known method.

[0042] [Method of Forming Resist Pattern] As described above, the lithography film-forming composition of the present invention is excellent as a material for forming a lithography underlayer film. Therefore, a resist pattern is preferably formed by a method of forming a resist pattern comprising a step of forming a lithography underlayer film on a substrate using the lithography film-forming composition. That is, the method of forming a resist pattern of the present invention is a method of forming a resist pattern using the lithography film-forming composition of the present invention. More specifically, a suitable pattern formation method of the present invention is a method of forming a resist pattern comprising the steps of forming an underlayer film precursor on a substrate using the lithography film-forming composition and heating the underlayer film precursor to 300°C or higher to form an underlayer film, forming at least one photoresist layer on the underlayer film, and irradiating the photoresist layer with radiation and developing it.

[0043] <Step of forming underlayer film> The step of forming an underlayer film is a step of forming an underlayer film precursor on a substrate using the lithography film-forming composition, and heating the underlayer film precursor to 300°C or higher to form an underlayer film.

[0044] The substrate used in this step may be a semiconductor substrate. As the semiconductor substrate, a silicon substrate (silicon wafer) can generally be used, but is not particularly limited thereto. Examples of the semiconductor substrate include Si, amorphous silicon (α-Si), p-Si, and SiO ２ , SiN, SiON, W, TiN, Al, or the like, which is different from the material of the processed layer. When a semiconductor substrate is used, a metal film, a metal carbide film, a metal oxide film, a metal nitride film, a metal carbide oxide film, or a metal oxynitride film formed on the semiconductor substrate can be used as the processed layer (processed portion). Examples of such a processed layer containing a metal include Si, SiO ２, SiN, SiON, SiOC, p-Si, α-Si, TiN, WSi, BPSG, SOG, Cr, CrO, CrON, MoSi, W, W-Si, Al, Cu, Al-Si, etc., as well as various low dielectric films and their etching stopper films, can be used, and can be formed to a thickness of usually 50 to 10,000 nm, particularly 100 to 5,000 nm.

[0045] This process involves forming an underlayer film on a substrate using the lithography film-forming composition. However, before forming the underlayer film using the lithography film-forming composition, an organic underlayer film or an organic hard mask can be formed on the substrate. The organic underlayer film can be formed from a coating-type organic underlayer film material using a spin-coating method or the like, and the organic hard mask can be formed from a carbon-based organic hard mask material using a CVD method. The types of such organic underlayer films and organic hard masks are not particularly limited, but when the top-layer resist film is to be patterned by exposure, those that exhibit sufficient anti-reflective coating function are preferred. By forming such an organic underlayer film or organic hard mask, the pattern formed in the top-layer resist film can be transferred onto the substrate (workpiece) without causing size conversion differences. A "carbon-based" hard mask refers to a hard mask in which 50% or more by mass of the solid content is composed of a carbon-based material, such as amorphous hydrogenated carbon, also known as amorphous carbon and denoted as a-C:H. While a-C:H films can be deposited by various techniques, plasma enhanced chemical vapor deposition (PECVD) is widely used due to its cost-effectiveness and film quality tunability. Examples of such hard masks include those described in JP 2013-526783 A. When forming an organic underlayer film on a substrate, this process involves forming an organic underlayer film on the substrate, forming an underlayer film precursor on the organic underlayer film using the lithography film-forming composition, and heating the underlayer film precursor to 300°C or higher to form an underlayer film. When forming an organic hard mask on a substrate, this process involves forming an organic hard mask on the substrate, forming an underlayer film precursor on the organic hard mask using the lithography film-forming composition, and heating the underlayer film precursor to 300°C or higher to form an underlayer film.

[0046] The method for forming an underlayer film precursor using the lithography film-forming composition is preferably to form it on a substrate or a workpiece provided with an organic underlayer film or the like by spin coating or the like. When forming the lithography film-forming composition on a substrate or a workpiece by spin coating, the lithography film-forming composition is first applied to the substrate or the workpiece. The content of the multi-branched tellurium-containing resin contained in the lithography film-forming composition may be appropriately adjusted taking into account the spin coating rotation speed, rotation time, viscosity of the composition, and evaporation rate of the solvent. The content of the multi-branched tellurium-containing resin contained in the lithography film-forming composition is preferably 0.001 to 10 g per 100 mL of solvent contained in the lithography film-forming composition. Next, the organic solvent is removed by volatilization to form an underlayer film precursor. The film thickness of the underlayer film precursor is preferably adjusted to 1 to 200 nm by adjusting the content of the multi-branched tellurium-containing resin, the spin coating rotation speed, rotation time, etc. Furthermore, when forming the underlayer film, a bake treatment is preferably performed in which the underlayer film is heated to 300°C or higher in order to suppress the occurrence of mixing with the upper layer resist and to promote the crosslinking reaction. In this case, the bake temperature is preferably 300°C or higher, more preferably 300 to 450°C, and even more preferably 300 to 400°C. The bake time is not particularly limited, but is preferably 10 to 300 seconds. In this manner, the underlayer film is formed on the substrate. The thickness of the underlayer film can be appropriately selected depending on the required performance and is not particularly limited, but is preferably 30 to 20,000 nm, and more preferably 50 to 15,000 nm.

[0047] <Step of Forming Photoresist Layer> Next, the step of forming a photoresist layer is carried out. The step of forming a photoresist layer is a step of forming at least one photoresist layer on the underlayer film.

[0048] This process forms a photoresist layer on the underlayer film. Examples of photoresist materials used for the photoresist layer include those that form a photoresist film, expose it, and then dissolve the exposed areas using an alkaline developer to form a positive pattern, or those that dissolve the unexposed areas using an organic solvent developer to form a negative pattern. When forming a photoresist layer using a photoresist material, wet processes such as spin coating and screen printing are preferably used. After applying the photoresist material using a spin coating method or the like, pre-baking is typically performed. This pre-baking is preferably performed under conditions of a baking temperature of 80 to 180°C and a baking time of 10 to 300 seconds. The thickness of the photoresist layer is not particularly limited, but is generally preferably 30 to 500 nm, more preferably 50 to 400 nm.

[0049] <Developing Step> Next, the developing step is performed. The developing step is a step of irradiating the photoresist layer with radiation and developing it, and in this step, by performing exposure and development as described above, a resist pattern can be obtained.

[0050] The radiation (exposure light) irradiated onto the photoresist layer may be appropriately selected depending on the photoresist material used. Generally, high-energy radiation with a wavelength of 300 nm or less, specifically, excimer lasers with wavelengths of 248 nm, 193 nm, or 157 nm, soft X-rays with wavelengths of 3 to 20 nm, electron beams, X-rays, etc., may be used. As a method for forming a pattern, any of the following methods can be suitably used: lithography using light with a wavelength of 300 nm or less or EUV light; electron beam direct writing; and directed self-assembly. By using such methods, fine patterns can be formed. The development method may be appropriately selected depending on the photoresist material used as the raw material for the photoresist layer. When a positive pattern is formed, it is preferable to dissolve the exposed portions using an alkaline developer to form a positive pattern. When a negative pattern is formed, it is preferable to dissolve the unexposed portions using a developer composed of an organic solvent to form a negative pattern. A resist pattern can be obtained in this manner.

[0051] Furthermore, from the viewpoint of improving sensitivity, processes using lithography underlayer films obtained using the lithography film-forming composition are particularly suitable when the exposure light is soft X-rays or X-rays with a wavelength of 3 to 20 nm. This is because, as described above, the lithography underlayer films obtained using the lithography film-forming composition of the present invention have excellent exposure light absorption capabilities, and are therefore able to exhibit a sensitizing effect on the upper layer resist composition. Furthermore, EUV light can also be suitably used as the exposure light. This is thought to be because the tellurium atoms contained in the lithography underlayer film contribute to the absorption of EUV light.

[0052]

[0023] Furthermore, the pattern formation method of the present invention preferably includes the steps of: using the resist pattern formed on the upper layer as described above as a mask to transfer a pattern to an underlayer film by etching, using the resist underlayer film to which the pattern has been transferred as a mask to transfer the pattern to the organic underlayer film by etching, and further using the organic underlayer film to which the pattern has been transferred as a mask to transfer the pattern to the substrate (workpiece) by etching.

[0024] Furthermore, as another aspect of the pattern formation method of the present invention, the pattern formation method of the present invention preferably includes the steps of: using the resist pattern formed on the upper layer as described above as a mask to transfer a pattern to the underlayer film by etching, using the underlayer film to which the pattern has been transferred as a mask to transfer the pattern to the organic hard mask by etching, and further using the organic hard mask to which the pattern has been transferred as a mask to transfer the pattern to the substrate (workpiece) by etching.

[0053] The present invention will be specifically described based on the following examples, but the present invention is not limited to these examples.

[0054] [Analysis] Fourier transform infrared spectroscopy (FT-IR) spectra were measured using a JASCO FT / IR4200 (manufactured by JASCO Corporation). 1 H-NMR spectra were measured using an FTECS-400K (manufactured by JEOL Ltd.) at a frequency of 400 MHz, using DMSO-d as the solvent and MeSi(TMS) as the internal standard. The number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) of the resin were measured by size exclusion chromatography (SEC) under the following conditions. Standard polystyrene (narrow molecular weight distribution) was used for calibration. (Measurement conditions: Apparatus: HLC-8220 SEC apparatus, manufactured by Tosoh Corporation; Columns: TSKgel Super AW3000, AW2500 x 2; Detection: RI, UV; Eluent: DMF)

[0055] [Evaluation 1 (Characteristic Evaluation of Hyperbranched Tellurium-Containing Resin and Lithography Film-Forming Composition)] <Thermal Stability (Heat Resistance)> The thermal stability of the hyperbranched tellurium-containing resin was measured by heating under nitrogen at a heating rate of 10°C / min using a thermogravimetric analyzer (TGA) TGA-50 / 50H (manufactured by Shimadzu Corporation). A weight loss of 3% or less at 90°C indicates excellent thermal stability, and a weight loss of 0% at 90°C (thermal decomposition onset temperature higher than 90°C) indicates even better thermal stability. The hyperbranched tellurium-containing resins obtained in Production Examples 1 to 5 have excellent thermal stability, as described below. Therefore, when used as raw materials for lithography film-forming compositions, they can withstand high temperatures of around 100°C during pre-baking and post-baking (PEB). Regarding thermal stability, resins with a thermal decomposition onset temperature of above 100°C were evaluated as "good."

[0056] <Solubility> The solubility of the hyperbranched tellurium-containing resin was confirmed by dissolving it in the following solvents at room temperature (25°C). The solvents tested were PGMEA, PGME, MEK, DMSO (dimethyl sulfoxide), DMF (N,N-dimethylformamide), THF (tetrahydrofuran), and chloroform. For each of the above solvents, the solubility was evaluated as good when 10 g or more of the resin was dissolved in 100 mL of the solvent. In Table 1, when the solubility was evaluated as good for all of the above solvents, the solubility was indicated as "good."

[0057] <Film Formability> The lithography film-forming compositions obtained in the examples (compositions containing 10 mg of a hyperbranched tellurium-containing resin (poly(Te-TMP)) and various solvents (100 mL) shown in the solubility evaluation above) were applied by spin coating to a silicon wafer treated with hexamethyldisilazane (HMDS), and dried at 110°C for 1 minute to form a resist film with a thickness of 10 nm. With regard to film formability, those which were able to form the above resist film were evaluated as having "good" film formability.

[0058] [Raw Materials] The raw materials used in the production examples are as follows. <Polyphenyl compound> TPM: triphenylmethane <Other raw materials> TeCl4: tellurium tetrachloride AlCl3: aluminum chloride CHCl3: chloroform (dried over P2O5 before use)

[0059] [Preparation of Hyperbranched Tellurium-Containing Resin] Preparation Example 1 (Preparation of poly(Te-TMP)) TeCl4 (0.174 g, 0.65 mmol), TPM (triphenylmethane) (0.474 g, 1.94 mmol), AlCl3 (0.29 g, 2.2 mmol), and CHCl3 (1.0 mL) were placed in a reaction vessel under an argon atmosphere and dissolved. The solution was stirred at 60°C for 48 hours and diluted with CHCl3. The resulting reaction mixture was poured into a large amount of ethyl ether to precipitate a solid. The solid was collected and dried under reduced pressure at room temperature for 24 hours to obtain a hyperbranched tellurium-containing resin (poly(Te-TMP)) (yield: 0.302 g). Table 1 shows the analytical results.

[0060] Furthermore, when the thermal stability of poly(Te-TMP) obtained in Production Example 1 was evaluated by the above-mentioned method, the thermal decomposition starting temperature was 270°C, and the weight residue at 450°C was 80% or more.

[0061] Preparation Example 2 (Preparation of poly(Te-TMP)) TeCl4 (0.404 g, 1.5 mmol), TPM (triphenylmethane) (0.244 g, 1.0 mmol), AlCl3 (0.29 g, 2.2 mmol), and CHCl3 (1.0 mL) were placed in a reaction vessel under an argon atmosphere and dissolved. The solution was stirred at 60°C for 48 hours and diluted with CHCl3. The resulting reaction mixture was poured into a large amount of ethyl ether to precipitate a solid. The solid was collected and dried under reduced pressure at room temperature for 24 hours to obtain a hyperbranched tellurium-containing resin (poly(Te-TMP)) (yield: 0.465 g). The analytical results are shown in Table 1 and below. IR (film, cm -1 ): 1635, 810 (ν C=C aromatic) 1 H-NMR (400MHz, DMSO-d6, TMS) δ (ppm): 5.38 (broad, >CH-), 7.03 (broad, aromatic protons)

[0062] [Preparation of Lithography Film-Forming Compositions] Examples 1 and 2 10 mg of the hyperbranched tellurium-containing resin (poly(Te-TMP)) obtained in Preparation Examples 1 and 2 was dissolved in 100 mL of each of the solvents shown in the solubility evaluation section above to obtain lithography film-forming compositions, and the film-forming properties were evaluated by the method described above. Furthermore, for solubility, 10 g of the hyperbranched tellurium-containing resin (poly(Te-TMP)) obtained in Preparation Examples 1 and 2 was dissolved in 100 mL of each of the solvents shown in the solubility evaluation section above to obtain lithography film-forming compositions, and the solubility was evaluated by the method described above. Example 1 is an example using the hyperbranched tellurium-containing resin (poly(Te-TMP)) of Preparation Example 1, and Example 2 is an example using the hyperbranched tellurium-containing resin (poly(Te-TMP)) of Preparation Example 2. The lithography film-forming compositions of Examples 1 and 2 exhibited good solubility and film-forming properties regardless of the solvent used.

[0063] The above results indicate that the hyperbranched tellurium-containing resin contained in the lithography film-forming composition of the present invention has high solubility in solvents, excellent film-forming properties, and high heat resistance. Therefore, the lithography film-forming composition of the present invention is an excellent material for forming a lithography film, and particularly an excellent material for forming a lithography underlayer film.

[0064] [Production of Hyperbranched Tellurium-Containing Resins] Production Examples 3 to 5 (Production of poly(Te-TMP)) Hyperbranched tellurium-containing resins (poly(Te-TMP)) were obtained in the same manner as in Production Example 1, except that TeCl4 and TPM (triphenylmethane) were used in a total amount of 0.648 g in the molar ratio shown in Table 1. The yield and analytical results are shown in Table 1.

[0065]

[0066] [Production and Evaluation of Lithography Film-Forming Composition 2 (Evaluation as a Resist Film-Forming Material)] Comparative Production Example 1 (Production of Modified Dimethylnaphthalene Formaldehyde Resin CR-1) A 10 L four-neck flask equipped with a Dimroth condenser, a thermometer, and a stirring blade and capable of being opened to the bottom was prepared. Into this four-neck flask, 1.09 kg (7 mol, manufactured by Mitsubishi Gas Chemical Co., Inc.), 2.1 kg of 40 wt% aqueous formalin solution (28 mol as formaldehyde, manufactured by Mitsubishi Gas Chemical Co., Inc.), and 0.97 mL of 98 wt% sulfuric acid (manufactured by Kanto Chemical Co., Inc.) were charged under a nitrogen gas flow, and the mixture was refluxed at 100°C for 7 hours. Subsequently, 1.8 kg of ethylbenzene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., special grade reagent) was added as a diluent to the reaction solution. After allowing to stand, the lower aqueous phase was removed. The mixture was neutralized and washed with water, and the ethylbenzene and unreacted 1,5-dimethylnaphthalene were distilled off under reduced pressure to obtain 1.25 kg of a light brown solid dimethylnaphthalene formaldehyde resin. The molecular weight Mn of the resulting dimethylnaphthalene formaldehyde was 562.

[0067] Next, a four-neck flask with an internal volume of 0.5 L equipped with a Dimroth condenser, a thermometer, and a stirring blade was prepared. Under a nitrogen stream, 100 g (0.51 mol) of the dimethylnaphthalene formaldehyde resin and 0.05 g of paratoluenesulfonic acid were charged into this four-neck flask, heated to 190°C, and heated for 2 hours, followed by stirring. Subsequently, 52.0 g (0.36 mol) of 1-naphthol was added, and the temperature was further increased to 220°C, followed by reaction for 2 hours. After solvent dilution, neutralization and water washing were performed, and the solvent was removed under reduced pressure to obtain 126.1 g of a modified resin (CR-1) as a black-brown solid. The resulting resin (CR-1) had an Mn of 885, an Mw of 2220, and an Mw / Mn of 4.17. The Mn, Mw and Mw / Mn of the resin (CR-1) were determined in terms of polystyrene by gel permeation chromatography (GPC) analysis under the following measurement conditions: Apparatus: Shodex GPC-101 (product of Showa Denko K.K.) Column: KF-80M x 3 Eluent: THF 1 mL / min Temperature: 40°C

[0068] Synthesis Example 1 (Synthesis of AC-1) A reaction solution was prepared by dissolving 4.15 g of 2-methyl-2-methacryloyloxyadamantane, 3.00 g of methacryloyloxy-γ-butyrolactone, 2.08 g of 3-hydroxy-1-adamantyl methacrylate, and 0.38 g of azobisisobutyronitrile in 80 mL of tetrahydrofuran. Under a nitrogen atmosphere, the reaction solution was stirred while maintaining the temperature at 63°C, and polymerization was carried out for 22 hours. Thereafter, the reaction solution was added dropwise to 400 mL of n-hexane. The obtained resin was coagulated and purified, and the resulting white powder was filtered and then dried overnight at 40°C under reduced pressure to obtain AC-1 represented by the following formula:

[0069]

[0070] In the formula of AC-1, "40", "40", and "20" indicate the ratio of each constituent unit, and do not indicate that it is a block copolymer.

[0071] Examples A1 to A9 and Comparative Example A1 (Production of Lithography Film-Forming Composition) Using the poly(Te-TMP) obtained in Production Examples 1 to 5 or CR-1 obtained in Comparative Production Example 1, the components were mixed until homogeneous according to the composition shown in Table 2 to produce lithography film-forming compositions having the compositions shown in Table 2. Furthermore, a composition for use as an etching rate evaluation standard was obtained in the same manner as in Example A1, except that a novolak resin (PSM4357 (model number), manufactured by Gunei Chemical Industry Co., Ltd.) was used instead of the poly(Te-TMP) obtained in Production Example 1.

[0072] The acid generator, acid diffusion controller, acid crosslinker, and organic solvent used were as follows: In Table 2, the numbers in parentheses indicate the blending amounts (parts by mass). <Acid generator> TPS-109: triphenylsulfonium trifluoromethanesulfonate, TPS-109 (trade name), manufactured by Midori Chemical Co., Ltd. DTDPI: ditertiarybutyldiphenyliodonium nonafluorobutanesulfonate (DTDPI), manufactured by Midori Chemical Co., Ltd. PPTS: pyridinium paratoluenesulfonate, manufactured by Kanto Chemical Co., Ltd. <Acid diffusion controller> TOA: tri-n-octylamine, manufactured by Kanto Chemical Co., Ltd. <Acid crosslinker> MW-100LM: Nikalac MW-100LM (trade name), manufactured by Sanwa Chemical Co., Ltd. MX270: Nikalac MX270 (trade name), manufactured by Sanwa Chemical Co., Ltd. TMOM-BP: manufactured by Honshu Chemical Industry Co., Ltd. <Organic solvent> Tetrahydrofuran (THF): manufactured by Kanto Chemical Co., Ltd. Propylene glycol monomethyl ether (PGME): manufactured by Kanto Chemical Co., Ltd.

[0073] (1) Formation of Resist Film The lithography film-forming composition shown in Table 2 was spin-coated on a silicon wafer treated with hexamethyldisilazane (HMDS), followed by pre-exposure baking (PB) in an oven at 110°C to form a resist film with a thickness of 40 nm.

[0074] (2) Formation of Resist Pattern and Evaluation of Pattern The resist film obtained in (1) above was irradiated with an electron beam using an electron beam lithography system (ELS-7500, manufactured by Elionix Co., Ltd., 50 keV) in a 1:1 line-and-space setting with 50 nm spacing. After irradiation, the resist film was heated at 110°C for 90 seconds and immersed in a developer for 60 seconds for development. The resist film was then washed with ultrapure water for 30 seconds and dried to form a resist pattern. In Examples A1 to A9, tetrahydrofuran (THF) was used as the developer, and in Comparative Example A1, propylene glycol monomethyl ether (PGME) was used as the developer.

[0075] The shape of the resulting resist pattern with an L / S (1:1) spacing of 50 nm was observed using an electron microscope (S-4800, product name, manufactured by Hitachi, Ltd.). The resist pattern shape after development was evaluated according to the following criteria. The evaluation results are shown in Table 2. A: No pattern collapse, and rectangularity was better than that of Comparative Example A1. B: The rectangularity was better than that of Comparative Example A1, but pattern collapse was observed in 1 to 3 places within an area of ​​1 μm × 1.5 μm. C: Equivalent to or inferior to Comparative Example A1. In Comparative Example A1, pattern collapse was observed in the resist pattern shape after development, and rectangularity was poor.

[0076] (3) Etching Resistance The resist film obtained in (1) above was subjected to an etching test to measure the etching rate under the following etching conditions.

[0077] (Etching conditions) Etching equipment: RIE-10NR (product name), manufactured by Samco Co., Ltd. Output: 50 W Pressure: 20 Pa Time: 2 minutes Etching gas: Ar gas Flow rate: CF ４ Gas flow rate: 0 ２ Gas flow rate = 50:5:5 (sccm)

[0078] The etching resistance of each resist film was evaluated according to the following criteria, using the etching rate of the resist film obtained from the reference composition using a novolak resin as the standard. The evaluation results are shown in Table 2.

[0079] (Evaluation criteria) A: The etching rate was less than -10% compared to the resist film obtained from the reference evaluation composition using a novolac resin. B: The etching rate was -10% or more and less than 0% compared to the resist film obtained from the reference evaluation composition using a novolac resin. C: The etching rate was 0% or more compared to the resist film obtained from the reference evaluation composition using a novolac resin.

[0080]

[0081] [Production and Evaluation of Lithography Film-Forming Compositions 3 (Evaluation as Lithography Underlayer Film-Forming Materials)] Examples B1 to B9 (Production of Lithography Film-Forming Compositions) Using the poly(Te-TMP) obtained in Production Examples 1 to 5, the components were mixed until homogeneous according to the compositions shown in Table 3 to produce lithography film-forming compositions having the compositions shown in Table 3.

[0082] The acid generators, acid crosslinkers, and organic solvents used were as follows. In Table 3, the values ​​in parentheses indicate the blending amounts (parts by mass). <Acid Generators> DTDPI: ditertiary butyldiphenyliodonium nonafluorobutanesulfonate (DTDPI), manufactured by Midori Chemical Co., Ltd. TPS-109: triphenylsulfonium trifluoromethanesulfonate, TPS-109 (trade name), manufactured by Midori Chemical Co., Ltd. PPTS: pyridinium paratoluenesulfonate, manufactured by Kanto Chemical Co., Ltd. <Acid Crosslinkers> MX270: Nikalac MX270 (trade name), manufactured by Sanwa Chemical Co., Ltd. MW-100LM: Nikalac MW-100LM (trade name), manufactured by Sanwa Chemical Co., Ltd. TMOM-BP: manufactured by Honshu Chemical Industry Co., Ltd. <Organic Solvents> N,N-dimethylformamide (DMF): manufactured by Kanto Chemical Co., Ltd.

[0083] (1) Formation of Resist Underlayer Film (Lithography Underlayer Film) The lithography film-forming composition shown in Table 3 was spin-coated onto a silicon wafer that had been treated with hexamethyldisilazane (HMDS), and then baked at 240°C for 60 seconds and then at 400°C for 120 seconds to form a resist underlayer film (lithography underlayer film) with a thickness of 70 nm.

[0084] (2) Evaluation of Resist Film Formation and Resolution A photoresist film with a thickness of 140 nm was formed by applying an ArF resist solution onto the resist underlayer film formed in (1) above and baking it at 130° C. for 60 seconds. The ArF resist solution used was prepared by mixing 5 parts by mass of the resin (AC-1) obtained in Synthesis Example 1 above, 1 part by mass of triphenylsulfonium nonafluoromethanesulfonate, 2 parts by mass of tributylamine, and 92 parts by mass of PGMEA.

[0085] The photoresist film was then exposed to light using an electron beam lithography system "ELS-7500" (product name, manufactured by Elionix Co., Ltd., 50 keV), baked at 115°C for 90 seconds (PEB), and developed with a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) for 60 seconds to obtain a positive resist pattern.

[0086] The results of observing defects in the resulting 55 nm L / S (1:1) and 80 nm L / S (1:1) resist patterns are shown in Table 3. In the table, the "good" result for the "resist pattern after development" indicates that no pattern collapse was observed in the formed resist pattern, and "poor" indicates that pattern collapse was observed in the formed resist pattern. Furthermore, as a result of the above observation, the minimum line width at which there was no pattern collapse and good rectangularity was used as an index for evaluation of "resolution." The results are shown in Table 3. Furthermore, a photoresist film was formed directly on a silicon wafer in the same manner as in Example B1, except that no resist underlayer film was formed, to obtain a positive resist pattern. The resulting resist pattern was then evaluated in the same manner as described above. This was designated Comparative Example B1. The results are shown in Table 3.

[0087]

[0088] From the results of the Examples, it can be seen that the resist film formed using the lithography film-forming composition of the Examples containing the multi-branched tellurium-containing resin can obtain a resist pattern with excellent pattern shape and also has excellent etching resistance. Furthermore, it can be seen that the resist underlayer film (lithography underlayer film) formed using the lithography film-forming composition of the Examples containing the multi-branched tellurium-containing resin can form a resist pattern with excellent resolution. Therefore, since the lithography film-forming composition of the present invention contains a multi-branched tellurium-containing resin that has high solubility in solvents, excellent film-forming properties, and high heat resistance, it is useful as a lithography film-forming material, and is particularly useful as a composition for forming a resist film and a resist underlayer film (lithography underlayer film).

Claims

1. A lithography film-forming composition containing a highly branched tellurium-containing resin obtained by an addition reaction between at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds and at least one tellurium compound selected from the group consisting of tellurium tetrachloride and tetraalkoxytellurium.

2. The lithography film-forming composition according to claim 1, comprising a highly branched tellurium-containing resin obtained by an addition reaction between at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds and tellurium tetrachloride.

3. The lithography film-forming composition according to claim 1, wherein the aromatic compound is at least one selected from the group consisting of triphenylmethane, tetraphenylmethane, anthracene, perylene, phenanthrene, and naphthalene.

4. The lithography film-forming composition according to claim 1, wherein the aromatic compound comprises a compound represented by the following formula (1). 【Chemistry 1】 (In the formula, R is a hydrogen atom, a methyl group, or a phenyl group.)

5. The lithography film-forming composition according to claim 1, wherein the multi-branched tellurium-containing resin contains at least one structural unit selected from the group consisting of structural units represented by the following formula (2), structural units represented by the following formula (3), and structural units represented by the following formula (4). 【Chemistry 2】 (In the formula, R is a hydrogen atom, a methyl group, or a phenyl group.)

6. The lithography film-forming composition according to claim 1, further comprising a solvent.

7. The lithography film-forming composition according to claim 1, further comprising at least one selected from the group consisting of an acid generator and an acid crosslinking agent.

8. The lithography film-forming composition according to claim 1, which is a lithography underlayer film-forming composition.

9. A lithography underlayer film formed from the lithography film-forming composition according to any one of claims 1 to 8.

10. A method for forming a resist pattern using the lithography film-forming composition described in any one of claims 1 to 8.

Images