Composition for forming an organic film, method of forming a pattern, and polymer

Abstract

The present invention relates to a composition for forming an organic film, a pattern forming method, and a polymer. The present invention provides a composition for forming an organic film, which contains a polymer having a high carbon content and being thermosetting, exhibits high etching resistance and excellent twist resistance, and provides a pattern forming method using this composition for forming an organic film, and a polymer suitable for this composition for forming an organic film. The composition for forming an organic film contains a polymer having a partial structure represented by the following general formula (1A) and an organic solvent. The polymer is crosslinked by a coupling reaction accompanied by dehydrogenation of hydrogens located at the trityl positions on the fluorene ring. [Chemical formula 1] #imgabs0#

Description

Technical Field

[0001] The present invention relates to a composition for forming an organic film, a method for forming a pattern using the composition, and a polymer contained in the composition. Background Art

[0002] In recent years, with the high integration and high speed of semiconductor elements, finer patterning rules have been required. For lithography using optical exposure, which is currently used as a general-purpose technology, various technical developments have been made on how to perform finer and more accurate pattern processing with the light source used.

[0003] Regarding the light source for lithography used in resist pattern formation, optical exposure using g-rays (436 nm) or i-rays (365 nm) of a mercury lamp as the light source is widely used in parts with a low density. On the other hand, in parts with a high density and the need for finer patterning, lithography using a KrF excimer laser (248 nm) or an ArF excimer laser (193 nm) with a shorter wavelength has been put into practical use. In the most advanced generations that require even finer patterning, lithography using extreme ultraviolet light (EUV, 13.5 nm) has also approached practical use.

[0004] If the thinning of the resist pattern continues as described above, in the single-layer resist method, which is a typical photoresist pattern formation method, it is known that the ratio of the height of the pattern to the line width of the pattern (aspect ratio) increases, and pattern collapse occurs due to the surface tension of the developer during development. When forming a pattern with a high aspect ratio on a substrate with a height difference, the multi-layer resist method of forming a pattern by laminating films with different dry etching characteristics is excellent. A two-layer resist method (Patent Document 1, etc.) combining a photoresist layer made of a silicon-containing photosensitive polymer and a lower layer made of an organic polymer having carbon, hydrogen, and oxygen as main constituent elements, such as a novolak-based polymer, and a three-layer resist method (Patent Document 2, etc.) combining a photoresist layer made of an organic photosensitive polymer used in the single-layer resist method, an intermediate layer made of a silicon-based polymer or a silicon-based CVD film, and a lower layer made of an organic polymer have been developed.

[0005] In this three-layer resist method, first, a fluorocarbon-based dry etching gas is used to transfer the pattern of the photoresist layer to the silicon-containing intermediate layer. Then, using this pattern as a mask, dry etching with an oxygen-containing gas is used to transfer the pattern to the organic lower layer film having carbon and hydrogen as main constituent elements. Then, using this as a mask, dry etching is used to form a pattern on the substrate to be processed. However, in the semiconductor element manufacturing process after the 20 nm generation, if the pattern of this organic lower layer film is used as a hard mask and the pattern is transferred to the substrate to be processed by dry etching, distortion and bending of the lower layer film pattern will be observed.

[0006] A carbon hard mask formed directly above a substrate to be processed is generally an amorphous carbon (hereinafter referred to as CVD-C) film made by using a CVD method with raw materials such as methane gas, ethane gas, acetylene gas, etc. In this CVD-C film, the hydrogen atoms in the film can be extremely few, and it is known to be very effective for the distortion and bending of patterns as described above. However, when there is a height difference in the substrate to be processed, it is also known that due to the characteristics of CVD processing, it is difficult to fill such a height difference flatly. Therefore, if a substrate with a height difference is filled with a CVD-C film and then patterned with a photoresist, a height difference will occur on the coating surface of the photoresist due to the influence of the height difference of the substrate to be processed, and thus the film thickness of the resist becomes uneven, resulting in deterioration of the focus margin and pattern shape during lithography.

[0007] On the other hand, when forming an underlying film of a carbon hard mask formed directly above a substrate to be processed by spin coating, it is known that there is an advantage that the height difference of a substrate with a height difference can be filled flatly. If the substrate is planarized using this underlying film material, the film thickness variation of the silicon-containing intermediate layer and photoresist formed thereon can be suppressed, the focus margin of lithography can be expanded, and a normal pattern can be formed.

[0008] Therefore, there is a need for an organic underlying film material that has high etching resistance during dry etching of a substrate to be processed and can form a film with high flatness on the substrate to be processed by spin coating, and a method for forming the organic underlying film.

[0009] In the past, regarding materials for forming organic films for the multilayer resist method, it has been known that condensation resins obtained by using carbonyl compounds such as ketones and aldehydes and aromatic alcohols as condensing agents for phenolic and naphtholic compounds are used in such underlying film materials. For example: the fluorene bisphenol novolak resin described in Patent Document 2, the bisphenol compound and its novolak resin described in Patent Document 3, the adamantane phenol compound novolak resin described in Patent Document 4, the binaphthol compound and its novolak resin described in Patent Document 5, etc. The resins used in such materials are composed mainly of naphthalene, fluorene, adamantane, etc. with a high carbon density, but it is inevitable to deteriorate the etching resistance due to the oxygen atom in the phenolic hydroxyl group.

[0010] Also, regarding resins for underlying film materials that do not contain heteroatoms such as oxygen so as not to impair the etching resistance, a resin having a fluorene structure described in Patent Document 6 has been cited. However, in order to form a cured film, a composition containing a crosslinking agent such as a hydroxymethyl compound is used to form a cured film. Therefore, even if the carbon content of the resin is increased, there is still a problem of impairing the etching resistance due to the crosslinking agent with a low carbon content.

[0011] Prior Art Documents

[0012] Patent Document

[0013] [Patent Document 1] Japanese Patent Laid-Open No. 6-118651, etc.

[0014] [Patent Document 2] Japanese Patent Laid-Open No. 2005-128509

[0015] [Patent Document 3] Japanese Patent Laid-Open No. 2006-293298

[0016] [Patent Document 4] Japanese Patent Laid-Open No. 2006-285095

[0017] [Patent Document 5] Japanese Patent Laid-Open No. 2010-122656

[0018] [Patent Document 6] Pamphlet of International Publication No. 2013 / 047106 Summary of the Invention

[0019] Problems to be Solved by the Invention

[0020] In view of the above facts, an object of the present invention is to provide a composition for forming an organic film that uses a polymer having a high carbon content and thermosetting properties in a composition for forming an organic film, which can exhibit high etching resistance and excellent twist resistance without loss of the original carbon content of the resin, and to provide a method for forming a pattern using such a composition for forming an organic film, and a polymer suitable for such a composition for forming an organic film.

[0021] Solutions for Solving the Problems

[0022] In order to achieve the above object, the present invention provides a composition for forming an organic film containing a polymer having a partial structure represented by the following general formula (1A) and an organic solvent.

[0023] [Chemical Formula 1]

[0024]

[0025] In the above general formula (1A), Ar1 and Ar2 are benzene rings or naphthalene rings which may have substituents.

[0026] When an organic film formed from a composition for forming an organic film containing a polymer having a partial structure represented by the above general formula (1A) is heated, a crosslinking reaction occurs due to a coupling reaction accompanied by dehydrogenation of hydrogen atoms at the trityl positions on the fluorene ring, and the entire coating film is formed only of a condensed aromatic ring structure having high etching resistance. As a result, an organic film formed of a condensed aromatic ring structure having high filling properties obtained by spin coating and containing no other heteroatoms can be formed, so that an organic film having high bending resistance and high dry etching resistance can be formed.

[0027] It is more preferable that the aforementioned polymer preferably has a partial structure represented by the following general formula (1B).

[0028] [Chemical formula 2]

[0029]

[0030] In the aforementioned general formula (1B), W1 is a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, or an organic group having one or more aromatic rings that may also have substituents, and Ar1 and Ar2 are benzene rings or naphthalene rings that may also have substituents.

[0031] By introducing such a partial structure into the main skeleton, it is possible to adjust required properties such as the etching resistance, solvent solubility, filling / planarization characteristics, etc. of this composition for forming an organic film.

[0032] It is more preferable that the aforementioned polymer preferably has a partial structure represented by the following general formula (1C).

[0033] [Chemical formula 3]

[0034]

[0035] In the aforementioned general formula (1C), W2 represents a monovalent organic group having 1 to 50 carbon atoms, and Ar1 and Ar2 are as described above.

[0036] By introducing such a partial structure into the main skeleton, it is possible to more finely adjust required properties such as the etching resistance, solvent solubility, filling / planarization characteristics, etc. of this composition for forming an organic film.

[0037] It is more preferable that the aforementioned polymer has a weight average molecular weight of 500 to 5000.

[0038] For a composition for forming an organic film containing a polymer having a weight average molecular weight within such a range, the solubility in an organic solvent can be maintained without impairment, and the evolution of gas during baking can be suppressed.

[0039] It is more preferable that the aforementioned organic solvent is a mixture of one or more organic solvents having a boiling point below 180 °C and one or more organic solvents having a boiling point of 180 °C or higher.

[0040] If the aforementioned organic solvent is the aforementioned mixture, by adding a high-boiling solvent to the aforementioned polymer to impart thermal fluidity to the organic film, it is possible to make the composition for forming an organic film have a high degree of filling / planarization characteristics.

[0041] It is more preferable that the aforementioned composition for forming an organic film further contains one or more of a surfactant and a plasticizer.

[0042] For a composition for forming an organic film containing the aforementioned additives, the coating property and filling / planarization characteristics are more excellent.

[0043] The present invention provides a pattern formation method, comprising the following steps: forming an organic film on a workpiece using the aforementioned composition for forming an organic film; forming a silicon-containing underlayer resist film on the aforementioned organic film using a silicon-containing underlayer resist film material; forming an upper resist film on the aforementioned silicon-containing underlayer resist film using a photoresist composition; forming a circuit pattern on the aforementioned upper resist film; using the upper resist film having the circuit pattern formed thereon as a mask to transfer the pattern to the aforementioned silicon-containing underlayer resist film by etching; using the silicon-containing underlayer resist film having the pattern transferred thereon as a mask to transfer the pattern to the aforementioned organic film by etching; and using the organic film having the pattern transferred thereon as a mask to form the pattern on the aforementioned workpiece by etching.

[0044] Through the aforementioned pattern formation method using a three-layer resist process, a fine pattern can be formed on a workpiece with high precision.

[0045] The present invention provides a pattern formation method, comprising the following steps: forming an organic film on a workpiece using the aforementioned composition for forming an organic film; forming a silicon-containing underlayer resist film on the aforementioned organic film using a silicon-containing underlayer resist film material; forming an organic anti-reflection coating (BARC) on the aforementioned silicon-containing underlayer resist film; forming an upper resist film on the aforementioned BARC using a photoresist composition; forming a circuit pattern on the aforementioned upper resist film; using the upper resist film having the circuit pattern formed thereon as a mask to sequentially transfer the pattern to the aforementioned BARC and the aforementioned silicon-containing underlayer resist film by etching; using the silicon-containing underlayer resist film having the pattern transferred thereon as a mask to transfer the pattern to the aforementioned organic film by etching; and using the organic film having the pattern transferred thereon as a mask to etch the aforementioned workpiece and form a pattern on the aforementioned workpiece.

[0046] Through the aforementioned pattern formation method using a four-layer resist process, a fine pattern can be formed on a workpiece with even higher precision.

[0047] The present invention provides a pattern formation method, comprising the following steps: forming an organic film on a workpiece using the aforementioned composition for forming an organic film; forming an inorganic hard mask selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the aforementioned organic film; forming an upper resist film on the aforementioned inorganic hard mask using a photoresist composition; forming a circuit pattern on the aforementioned upper resist film; using the upper resist film having the circuit pattern formed thereon as a mask to transfer the pattern to the aforementioned inorganic hard mask by etching; using the inorganic hard mask having the pattern formed thereon as a mask to transfer the pattern to the aforementioned organic film by etching; and using the organic film having the pattern formed thereon as a mask to etch the aforementioned workpiece and form a pattern on the aforementioned workpiece.

[0048] By using the pattern formation method achieved by this three-layer resist process, a fine pattern can be formed on the substrate to be processed with high precision.

[0049] Furthermore, the present invention provides a pattern formation method, comprising the following steps: forming an organic film on the object to be processed using the aforementioned composition for forming an organic film; forming an inorganic hard mask selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the aforementioned organic film; forming a BARC on the aforementioned inorganic hard mask; forming an upper resist film using a photoresist composition on the aforementioned BARC; forming a circuit pattern on the aforementioned upper resist film; using the upper resist film on which the circuit pattern has been formed as a mask, and transferring the pattern to the aforementioned BARC and the aforementioned inorganic hard mask by etching in sequence; using the inorganic hard mask on which the pattern has been formed as a mask, and transferring the pattern to the aforementioned organic film by etching; using the organic film on which the pattern has been formed as a mask, etching the aforementioned object to be processed, and forming a pattern on the aforementioned object to be processed.

[0050] By using the pattern formation method achieved by this four-layer resist process, a fine pattern can be formed on the substrate to be processed with even higher precision.

[0051] It is preferable that the aforementioned inorganic hard mask is formed by CVD method or ALD method.

[0052] If the aforementioned inorganic hard mask is formed by CVD method or ALD method, a fine pattern can be formed on the substrate to be processed with higher precision.

[0053] Regarding the method of forming a circuit pattern on the aforementioned upper resist film, it is preferable to use photolithography with a wavelength of 10 nm or more and 300 nm or less, direct drawing using an electron beam, nanoimprint, or a combination thereof.

[0054] Regarding the method of forming a circuit pattern on the aforementioned upper resist film, if the aforementioned method is used, a fine pattern can be formed on the substrate to be processed with high precision.

[0055] Regarding the development method, it is preferable to use alkali development or development using an organic solvent.

[0056] Regarding the development method, if alkali development or development using an organic solvent is used, a fine pattern can be formed on the substrate to be processed with higher precision.

[0057] It is preferable that the aforementioned object to be processed is a semiconductor device substrate, a metal film, a metal carbide film, a metal oxide film, a metal nitride film, a metal oxycarbide film, or a metal oxynitride film.

[0058] In the present invention, the aforementioned object to be processed can be used as the aforementioned, for example.

[0059] Preferably, the aforementioned metal is silicon, titanium, tungsten, hafnium, zirconium, chromium, germanium, copper, silver, gold, aluminum, indium, gallium, arsenic, palladium, iron, tantalum, iridium, molybdenum, or an alloy thereof.

[0060] The aforementioned metal can be like this.

[0061] The present invention provides a polymer having a partial structure represented by the following general formula (1A).

[0062] [Chemical formula 4]

[0063]

[0064] In the above general formula (1A), Ar1 and Ar2 are benzene rings or naphthalene rings which may have substituents.

[0065] This polymer is a component of an organic film-forming composition that provides high filling property obtained by spin coating and forms an organic film composed of a condensed aromatic ring structure without other heteroatoms, thereby enabling the formation of an organic film with high bending resistance and high dry etching resistance.

[0066] Preferably, the aforementioned polymer further has a partial structure represented by the following general formula (1B).

[0067] [Chemical formula 5]

[0068]

[0069] In the above general formula (1B), W1 is a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, or an organic group having one or more aromatic rings which may have substituents, and Ar1 and Ar2 are benzene rings or naphthalene rings which may have substituents.

[0070] If the aforementioned polymer further has the aforementioned partial structure, it will become an organic film-forming composition that can form an organic film with high bending resistance and high dry etching resistance.

[0071] Preferably, the aforementioned polymer further has a partial structure represented by the following general formula (1C).

[0072] [Chemical formula 6]

[0073]

[0074] In the above general formula (1C), W2 represents a monovalent organic group having 1 to 50 carbon atoms, and Ar1 and Ar2 are as described above.

[0075] If the aforementioned polymer further has the aforementioned partial structure, it will become a component of an organic film-forming composition that can form an organic film with high bending resistance and high dry etching resistance.

[0076] Effects of the Invention

[0077] As described above, the polymer of the present invention has thermosetting properties and is composed only of condensed aromatic rings without heteroatoms that would impair etching resistance. Therefore, it becomes a useful polymer for forming an organic film with excellent etching resistance and distortion resistance. Further, the composition for forming an organic film of the present invention containing this polymer is a useful material for forming an organic film having excellent etching resistance, distortion resistance, and various properties such as heat resistance, filling, and planarization characteristics. Therefore, for example, it is extremely useful as an underlayer resist film material in multi-layer resist processes such as two-layer resist processing, three-layer resist processing using a silicon-containing underlayer resist film, or four-layer resist processing using a silicon-containing underlayer resist film and an organic antireflection film. Further, in the case of the pattern formation method of the present invention, in multi-layer resist processing, a fine pattern can be formed with high precision on a substrate to be processed. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 (A) to (F) are processing diagrams showing an example of the pattern formation method of the present invention.

[0079] Figure 2 It is a cross-sectional view showing an example of an organic film formed by coating the composition for forming an organic film of the present invention on a SiO2 wafer substrate having a trench pattern. DETAILED DESCRIPTION OF THE INVENTION

[0080] As described above, there is a need to develop a composition for forming an organic film, a pattern formation method using this composition, and a polymer suitable for such a composition for forming an organic film that can exhibit high etching resistance and excellent distortion resistance without sacrificing the original carbon content of the resin by using a polymer with a high carbon content and thermosetting properties in the composition for forming an organic film.

[0081] The inventors of the present case diligently studied the above problems and as a result, found that a polymer having a specific partial structure in which hydrogen is located at the trityl position of a fluorene ring crosslinks due to a coupling reaction accompanied by dehydrogenation of the hydrogens at the trityl positions. Therefore, a composition for forming an organic film containing the above polymer and an organic solvent has high filling properties obtained by spin coating and gives an organic film having high bending resistance and dry etching resistance formed of a resin having a condensed aromatic ring structure without heteroatoms, thus completing the present invention.

[0082] That is, the present invention is a composition for forming an organic film containing a polymer having a partial structure represented by the following general formula (1A) and an organic solvent.

[0083] [Chemical Formula 7]

[0084]

[0085] In the aforementioned general formula (1A), Ar1 and Ar2 are benzene rings or naphthalene rings which may also have substituents.

[0086] The following describes the embodiments of the present invention in detail, but the present invention is not limited thereto.

[0087] The composition for forming an organic film of the present invention contains a polymer having a partial structure represented by the following general formula (1A).

[0088] [Chemical formula 8]

[0089]

[0090] In the above general formula (1A), Ar1 and Ar2 are benzene rings or naphthalene rings which may also have substituents.

[0091] Examples of the partial structure composed of Ar1 and Ar2 in the polymer in the aforementioned general formula (1A) are as follows. These aromatic rings may also have substituents such as vinyl, ethynyl, ethynylphenyl, allyl, propargyl, aryl, allyloxy, and propargyloxy. Among the following, considering the ease of obtaining raw materials, a fluorene or benzo[b]fluorene structure is preferred.

[0092] [Chemical formula 9]

[0093]

[0094] It is preferred that the aforementioned polymer further has a partial structure represented by the following general formula (1B).

[0095] [Chemical formula 10]

[0096]

[0097] In the aforementioned general formula (1B), W1 is a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, or an organic group having one or more aromatic rings which may also have substituents, and Ar1 and Ar2 are benzene rings or naphthalene rings which may also have substituents.

[0098] Examples of the organic group having one or more aromatic rings in W1 in the aforementioned general formula (1B) are as follows. These aromatic rings may also have substituents such as vinyl, ethynyl, ethynylphenyl, allyl, propargyl, aryl, allyloxy, and propargyloxy. From the viewpoints of imparting etching resistance and solvent solubility, it is preferred that the aforementioned organic group has a naphthalene ring, a fluorene structure, or a carbazole structure.

[0099] [Chemical formula 11]

[0100]

[0101] [Chemical formula 12]

[0102]

[0103] [Chemical Formula 13]

[0104]

[0105] In the present invention, it is preferable that the aforementioned polymer has a partial structure represented by (1C).

[0106] [Chemical Formula 14]

[0107]

[0108] In the aforementioned general formula (1C), W2 represents a monovalent organic group having 1 to 50 carbon atoms, and Ar1 and Ar2 are as described above.

[0109] Examples of W2 in the aforementioned general formula (1C) include alkyl groups having 1 to 10 carbon atoms, ethynyl groups, propargyl groups, or the following structures, etc. When W2 has an aromatic ring, the aromatic ring may also have substituents such as hydroxyl groups, alkyl groups having 1 to 10 carbon atoms, alkoxy groups having 1 to 10 carbon atoms, vinyl groups, ethynyl groups, ethynylphenyl groups, allyl groups, propargyl groups, and aryl groups. Among them, from the viewpoints of imparting etching resistance and solvent solubility, those having a propargyl group or a naphthyl group are preferable.

[0110] [Chemical Formula 15]

[0111]

[0112] It is preferable that the Mw (weight average molecular weight) of the aforementioned polymer is 500 to 5000, and it is more preferable that the aforementioned Mw is 600 to 4000.

[0113] If the molecular weight is such, the solubility in an organic solvent can be ensured, and the sublimates generated during baking can be suppressed. Moreover, the thermal fluidity of the composition for forming an organic film becomes good, so that the fine structure formed on the substrate can be well filled with the aforementioned composition for forming an organic film. Not only that, an organic film with a flat substrate as a whole can be formed. In the present invention, the weight average molecular weight is a polystyrene conversion value obtained by measurement using GPC (gel permeation chromatography) with THF (tetrahydrofuran) as the developing solvent.

[0114] [Manufacturing method of polymer]

[0115] As an example of the manufacturing method of the polymer represented by the general formula (1A) of the present invention, an electrophilic substitution reaction on the fluorene ring accompanied by dehydration using a fluorenol having a tertiary alcohol group shown below as a monomer can be cited. Ar1 and Ar2 in the following formula are as described above.

[0116] [Chemical Formula 16]

[0117]

[0118] The aforementioned polymer can generally be obtained in an organic solvent in the presence of an acid catalyst at room temperature or with cooling or heating as required. Examples of acid catalysts that can be used include inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and heteropolyacids; organic acids such as oxalic acid, trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, and trifluoromethanesulfonic acid; and Lewis acids such as aluminum trichloride, aluminum ethoxide, aluminum isopropoxide, boron trifluoride, boron trichloride, boron tribromide, tin tetrachloride, tin tetrabromide, dibutyltin dichloride, dibutyltin dimethoxide, dibutyltin oxide, titanium tetrachloride, titanium tetrabromide, titanium(IV) methoxide, titanium(IV) ethoxide, titanium(IV) isopropoxide, and titanium(IV) oxide.

[0119] There are no special restrictions on the solvents that can be used. Examples include alcohols such as methanol, ethanol, isopropanol, butanol, ethylene glycol, propylene glycol, diethylene glycol, glycerol, ethylene glycol monomethyl ether, and propylene glycol monomethyl ether; ethers such as diethyl ether, dibutyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, and 1,4-dioxane; chlorinated solvents such as dichloromethane, chloroform, dichloroethane, and trichloroethylene; hydrocarbons such as hexane, heptane, benzene, toluene, xylene, and cumene; nitriles such as acetonitrile; ketones such as acetone, ethyl methyl ketone, and isobutyl methyl ketone; esters such as ethyl acetate, n-butyl acetate, and propylene glycol methyl ether acetate; and aprotic polar solvents such as dimethyl sulfoxide, N,N-dimethylformamide, and hexamethylphosphoric triamide. These can be used alone or in combination of two or more.

[0120] Regarding the reaction method, there are methods of charging the fluorene alcohols and the catalyst acid catalyst all at once, methods of dispersing or dissolving the fluorene alcohols and then adding the catalyst batchwise or in portions, methods of diluting the catalyst with a solvent and adding it dropwise, methods of dispersing or dissolving the catalyst and then adding the fluorene alcohols batchwise or in portions, and methods of diluting the fluorene alcohols with a solvent and adding it dropwise. After the reaction is completed, in order to remove the catalyst used in the reaction, the reaction product can be diluted with an organic solvent, followed by liquid separation and washing, and the target product can be recovered.

[0121] The organic solvent used at this time only needs to be able to dissolve the target product and will separate into two layers even when mixed with water, and there are no special restrictions. For example, hydrocarbons such as hexane, heptane, benzene, toluene, and xylene; esters such as ethyl acetate, n-butyl acetate, and propylene glycol methyl ether acetate; ketones such as methyl ethyl ketone, methyl amyl ketone, cyclohexanone, and methyl isobutyl ketone; ethers such as diethyl ether, diisopropyl ether, methyl tert-butyl ether, and ethyl cyclopentyl methyl ether; chlorinated solvents such as dichloromethane, chloroform, dichloroethane, and trichloroethylene; and mixtures thereof. The washing water used at this time can be ordinary deionized water or ultrapure water. The number of washing times can be 1 or more, but since there is no corresponding effect even after washing 10 or more times, it is preferably about 1 to 5 times.

[0122] At the time of liquid separation washing, in order to remove acidic components in the system, an alkaline aqueous solution can also be used for washing. Specifically, examples of the alkali include hydroxides of alkali metals, carbonates of alkali metals, hydroxides of alkaline earth metals, carbonates of alkaline earth metals, ammonia, and organic ammonium salts.

[0123] Also, at the time of liquid separation washing, in order to remove metal impurities or alkaline components in the system, an acidic aqueous solution can be used for washing. Specifically, examples of the acid include inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and heteropoly acids; organic acids such as oxalic acid, fumaric acid, maleic acid, trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, and trifluoromethanesulfonic acid.

[0124] The above-mentioned liquid separation washing using an alkaline aqueous solution and an acidic aqueous solution can be carried out only one of them, or can be carried out in combination. If the liquid separation washing is carried out in order with an alkaline aqueous solution and an acidic aqueous solution, it is more ideal from the viewpoint of removing metal impurities.

[0125] After the above-mentioned liquid separation washing using an alkaline aqueous solution and an acidic aqueous solution, it can be followed by washing with neutral water. The number of washing times is 1 or more, but preferably about 1 to 5 times. As the neutral water, the above-mentioned deionized water, ultrapure water, etc. can be used. The number of washing times can be 1 or more, but when the number of times is small, sometimes the alkaline components and acidic components cannot be removed. Even if the washing is carried out 10 times or more, the corresponding washing effect may not necessarily be obtained, so it is preferably about 1 to 5 times.

[0126] Also, the reaction product after the liquid separation operation can also be concentrated and dried or crystallized the solvent under reduced pressure or normal pressure to recover it in the form of a powder. However, in order to improve the operability when preparing the composition for forming an organic film, it can also be first made into a solution state with an appropriate concentration. The concentration at this time is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by weight. If it is such a concentration, the viscosity is not likely to become high, it is possible to prevent damage to the operability, and also, the amount of the solvent does not become too large, so it is economical.

[0127] Regarding the solvent at this time, there is no particular limitation as long as it can dissolve the polymer. Specific examples include ketones such as cyclohexanone and methyl-2-pentanone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monoterbutyl ether acetate. They can be used alone or in combination of two or more.

[0128] The polymer having a partial structure represented by the general formula (1B) of the present invention can be produced by copolymerizing a fluorene alcohol, which is a raw material for producing a polymer having a partial structure represented by the general formula (1A), with a compound having a partial structure of W1, or by adding a compound having a partial structure of W1 to the reaction of a polymer having a partial structure represented by the general formula (1A) and capping the ends. Ar1, Ar2, and W1 in the following formula are as described above. When W1 is a hydroxyl group or an alkoxy group, it can be produced by pre-adding water or alcohol to the reaction system or adding water or alcohol during the reaction.

[0129] (Copolymerization method)

[0130] [Chemical formula 17]

[0131]

[0132] (End-capping method)

[0133] [Chemical formula 18]

[0134]

[0135] When the above reaction is carried out using a compound having an organic group with one or more aromatic rings as W1, the compound having a partial structure of W1 acts as a terminal stopper for the polymer of fluorene alcohol during polymerization. As shown below during the reaction, there may be a possibility that the aromatic ring of the compound having a partial structure of W1 reacts with fluorene alcohol polymers having different chain lengths. However, for the sake of simplicity, the present invention is represented and described in the form of the general formula (1B). Ar1 and Ar2 are as described above, and n1, n2, and n3 are integers of 1 or more.

[0136] [Chemical formula 19]

[0137]

[0138] The reaction and recovery methods of the polymer having a partial structure represented by the general formula (1B) are the same as those of the polymer having a partial structure represented by the general formula (1A).

[0139] Examples of the polymer having a partial structure represented by the general formula (1C) of the present invention include a method of copolymerizing by charging fluorenols, which are raw materials for producing a polymer having a partial structure represented by the general formula (1A), and fluorenols having a partial structure of W2 at once, or a method of polymerizing fluorenols, which are raw materials for a polymer having a partial structure represented by the general formula (1A), or fluorenols having a partial structure of W2 in the first stage and then adding and polymerizing fluorenols different from those in the first stage in the second stage. Further, when polymerizing in two stages, a plurality of fluorenols may be mixed and used in the polymerization in the first stage or the second stage, and the same or other fluorenols may be further added and polymerized in the third stage and the fourth stage. In such polymerization, a partial structure of W1 may be introduced by copolymerization or capping using a compound having a partial structure of the aforementioned W1.

[0140] (Copolymerization method)

[0141] [Chemical formula 20]

[0142]

[0143] (Multi-stage polymerization method)

[0144] [Chemical formula 21]

[0145]

[0146] In the same manner as in the reaction of the aforementioned polymerization and fluorenols with a compound having an organic group having one or more aromatic rings as W1, for example, as shown in the following formula, there is a possibility of reacting with a plurality of fluorenol polymers formed during polymerization on the aromatic rings of Ar1 and Ar2 of fluorenols having W2 as a partial structure. In the present invention, for simplicity, it is represented and described in the form of Chemical formula (1C). Ar1 and Ar2 are as described above, and n1, n2, and n3 are integers of 1 or more.

[0147] [Chemical formula 22]

[0148]

[0149] The reaction and recovery methods of the aforementioned polymer are the same as those of the polymer having a partial structure represented by the general formula (1A).

[0150] In the polymerization of the polymer having the partial structure represented by the general formula (1A) of the present invention, in addition to fluorene alcohols, fluorene alcohols having W1 or W2 as a partial structure can be used in combination according to the required properties. Specifically, a side chain structure that contributes to the improvement of the planarization property and a rigid aromatic ring structure that contributes to the improvement of the etching resistance and heat resistance can be introduced into the structure of the fluorene alcohol having W1 or W2 as a partial structure and then used, and the raw materials can also be combined in any ratio according to the required properties. Moreover, the manufacturing method of the polymer can also be selected according to the required properties, and by appropriately selecting copolymerization, multi-stage polymerization, and capping methods, the structure of the polymer such as random and alternating polymerization can be controlled. The composition for forming an organic film using the polymer can achieve high-dimensional balance of the filling / planarization property, heat resistance, twist resistance, and etching resistance.

[0151] As described above, for the polymer having the partial structure represented by the general formula (1A) of the present invention, a composition for forming an organic film that can exhibit high etching resistance and excellent twist resistance can be provided.

[0152] <Composition for forming an organic film>

[0153] Furthermore, the present invention provides a composition for forming an organic film containing a polymer having the partial structure represented by the general formula (1A) and an organic solvent. Moreover, in the composition for forming an organic film of the present invention, a plurality of polymers having the partial structure represented by the general formula (1A) of the present invention can be used alone or in combination.

[0154] In the composition for forming an organic film of the present invention, a modifier such as a compound for blending, other polymers, etc. may be further blended. The function of the aforementioned modifier is to mix with the composition for forming an organic film of the present invention and improve the film-forming property of spin coating and the filling property on a substrate with height differences. Examples of such modifiers include phenol, o-cresol, m-cresol, p-cresol, 2,3-dimethylphenol, 2,5-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,4-dimethylphenol, 2,6-dimethylphenol, 2,3,5-trimethylphenol, 3,4,5-trimethylphenol, 2-tert-butylphenol, 3-tert-butylphenol, 4-tert-butylphenol, 2-phenylphenol, 3-phenylphenol, 4-phenylphenol, 3,5-diphenylphenol, 2-naphthol, 3-naphthol, 4-naphthol, 4-tritylphenol, resorcinol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, catechol, 4-tert-butylcatechol, 2-methoxyphenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, 2-methoxy-5-methylphenol, 2-tert-butyl-5-methylphenol, gallic acid, thymol, isothymol, 4,4'-(9H-fluoren-9-ylidene)bisphenol, 2,2'-dimethyl-4,4'-(9H-fluoren-9-ylidene)bisphenol, 2,2'-diallyl-4,4'-(9H-fluoren-9-ylidene)bisphenol, 2,2'-difluoro-4,4'-(9H-fluoren-9-ylidene)bisphenol,Novolac resins such as 6-dihydroxynaphthalene, 3-hydroxynaphthalene-2-carboxylic acid methyl, indene, hydroxyindene, benzofuran, hydroxyanthracene, vinylnaphthalene, biphenyl, bisphenol, trisphenol, dicyclopentadiene, tetrahydroindene, 4-vinylcyclohexene, norbornene, 5-vinylnorbornene-2-ene, α-pinene, β-pinene, and limonene, polyhydroxystyrene, polystyrene, polyvinylnaphthalene, polyvinylanthracene, polyvinylcarbazole, polyindene, polyvinylnaphthalene, polynorbornene, polycyclodecene, polytetracyclododecene, polytricyclo[2.2.1.0(2,6)]heptane (poly-nortricyclene), poly(meth)acrylates, and copolymers thereof. Furthermore, naphthol-dicyclopentadiene copolymers described in JP-A-2004-205685, fluorene bisphenol novolac resins described in JP-A-2005-128509, ethylene-naphthalene copolymers described in JP-A-2005-250434, fullerenes having phenol groups described in JP-A-2006-227391, bisphenol compounds and novolac resins thereof described in JP-A-2006-293298, novolac resins of adamantanephenol compounds described in JP-A-2006-285095, bisnaphthol compounds and novolac resins thereof described in JP-A-2010-122656, and fullerene resin compounds described in JP-A-2008-158002 may also be blended. The amount of the modifier is preferably 0 to 1,000 parts by mass, more preferably 0 to 500 parts by mass, relative to 100 parts by mass of the polymer having the partial structure represented by the general formula (1A) of the present invention.

[0155] [Organic solvents]

[0156] The organic solvent that can be used in the organic film-forming composition of the present invention is not particularly limited as long as it dissolves the polymer having the partial structure represented by general formula (1A), the acid generator, the crosslinking agent, and other additives. Specifically, solvents having a boiling point of less than 180°C, such as those described in paragraphs (0091) and (0092) of JP-A-2007-199653, can be used. Among these, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, 2-heptanone, cyclopentanone, cyclohexanone, and mixtures of two or more thereof are preferred.

[0157] Such a composition can be applied by spin coating and contains a polymer having a partial structure represented by the general formula (1A) of the present invention, thereby becoming an organic film-forming composition having good dry etching resistance and heat resistance as well as high filling / planarization properties.

[0158] Furthermore, in the composition for forming an organic film of the present invention, with respect to the organic solvent, a high-boiling solvent having a boiling point of 180°C or higher may be added to the solvent having a boiling point of less than 180°C (a mixture of a solvent having a boiling point of less than 180°C and a solvent having a boiling point of 180°C or higher). With respect to the high-boiling organic solvent, as long as it can dissolve the polymer having the partial structure represented by the general formula (1A), there are no special restrictions such as hydrocarbons, alcohols, ketones, esters, ethers, and chlorinated solvents. Specific examples may include 1-octanol, 2-ethylhexanol, 1-nonanol, 1-decanol, 1-undecanol, ethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, glycerol, n-nonyl acetate, ethylene glycol monohexyl ether, ethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, diethylene glycol monophenyl ether, diethylene glycol monobenzyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol monomethyl ether, triethylene glycol-n-butyl ether, triethylene glycol butyl methyl ether, triethylene glycol diacetate, tetraethylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol mono-n-propyl ether, tripropylene glycol mono-n-butyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, triacetin, propylene glycol diacetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol methyl-n-propyl ether, dipropylene glycol methyl ether acetate, 1,4-butanediol diacetate, 1,3-butanediol diacetate, 1,6-hexanediol diacetate, triethylene glycol diacetate, γ-butyrolactone, dihexyl malonate, diethyl succinate, dipropyl succinate, dibutyl succinate, dihexyl succinate, dimethyl adipate, diethyl adipate, dibutyl adipate, etc. They may be used alone or in combination.

[0159] The boiling point of the aforementioned high-boiling solvent may be appropriately selected according to the temperature for heat-treating the composition for forming an organic film. The boiling point of the added high-boiling solvent is preferably 180°C to 300°C, more preferably 200°C to 300°C. If the aforementioned boiling point is 180°C or higher, there is no risk of excessive volatilization during baking (heat treatment) due to too low a boiling point, and sufficient thermal fluidity can be obtained. Also, if the aforementioned boiling point is 300°C or lower, the boiling point is not too high, and there is no situation where the aforementioned high-boiling solvent does not volatilize and remains in the organic film after baking, so there is no risk of adversely affecting the physical properties of the organic film such as etching resistance.

[0160] When using the aforementioned high-boiling-point solvent, the amount of the high-boiling-point solvent blended is preferably 1 to 30 parts by mass per 100 parts by mass of the solvent having a boiling point of less than 180° C. With such a blending amount, there is no risk of the solvent failing to impart sufficient thermal fluidity during baking or remaining in the organic film and deteriorating film properties such as etching resistance.

[0161] Such an organic film-forming composition can achieve both high filling and planarizing properties by adding a high-boiling-point solvent to the polymer having the partial structure represented by general formula (1A) to impart thermal fluidity.

[0162] [Other additives]

[0163] An acid generator may be added to the organic film-forming composition of the present invention to further promote the curing reaction. Acid generators may generate acid by thermal decomposition or by light irradiation. Specifically, the materials described in paragraphs (0061) to (0085) of JP-A-2007-199653 may be added, but the present invention is not limited thereto.

[0164] The acid generator may be used alone or in combination of two or more. The amount of the acid generator added is preferably 0.05 to 50 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the polymer having the partial structure represented by formula (1A).

[0165] The organic film-forming composition of the present invention may contain a surfactant to improve the coating properties during spin coating. For example, surfactants described in JP-A-2009-269953 (0142) to (0147) can be used.

[0166] Furthermore, a crosslinking agent may be added to the organic film-forming composition of the present invention to enhance curability and further inhibit cross-mixing with the overlying film. The crosslinking agent is not particularly limited, and various known crosslinking agents can be used. Examples include melamine-based crosslinking agents, glycoluril-based crosslinking agents, benzoguanamine-based crosslinking agents, urea-based crosslinking agents, β-hydroxyalkylamide-based crosslinking agents, isocyanurate-based crosslinking agents, aziridine-based crosslinking agents, oxazoline-based crosslinking agents, and epoxy-based crosslinking agents.

[0167] In the case of melamine-based crosslinking agents, specifically, hexamethoxymethylated melamine, hexabutoxymethylated melamine, their alkoxy and / or hydroxy substituents, and their partial self-condensates can be cited. In the case of glycoluril-based crosslinking agents, specifically, tetramethoxymethylated glycoluril, tetrabutoxymethylated glycoluril, their alkoxy and / or hydroxy substituents, and their partial self-condensates can be cited. In the case of benzoguanamine-based crosslinking agents, specifically, tetramethoxymethylated benzoguanamine, tetrabutoxymethylated benzoguanamine, their alkoxy and / or hydroxy substituents, and their partial self-condensates can be cited. In the case of urea-based crosslinking agents, specifically, dimethoxymethylated dimethoxyethyleneurea, its alkoxy and / or hydroxy substituents, and their partial self-condensates can be cited. In the case of β-hydroxyalkylamide-based crosslinking agents, specifically, N,N,N’,N’-tetrakis(2-hydroxyethyl)adipamide can be cited. In the case of isocyanurate-based crosslinking agents, specifically, triglycidyl isocyanurate and triallyl isocyanurate can be cited. In the case of aziridine-based crosslinking agents, specifically, 4,4’-bis(ethyleneiminocarbonylamino)diphenylmethane and 2,2-bis(hydroxymethyl)butanol-tris[3-(1-aziridinyl)propionate] can be cited. In the case of oxazoline-based crosslinking agents, specifically, 2,2’-isopropylidenebis(4-benzyl-2-oxazoline), 2,2’-isopropylidenebis(4-phenyl-2-oxazoline), 2,2’-isopropylidenebis(4-phenyl-2-oxazoline), 2,2’-methylenebis4,5-diphenyl-2-oxazoline, 2,2’-methylenebis-4-phenyl-2-oxazoline, 2,2’-methylenebis-4-tert-butyl-2-oxazoline, 2,2’-bis(2-oxazoline), 1,3-phenylenebis(2-oxazoline), 1,4-phenylenebis(2-oxazoline), and 2-isopropenyl oxazoline copolymer can be cited. In the case of epoxy-based crosslinking agents, specifically, diglycidyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, poly(glycidyl methacrylate), trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether, and pentaerythritol tetraglycidyl ether can be cited.

[0168] Furthermore, in the composition for forming an organic film of the present invention, a plasticizer can be added in order to improve the planarization / embedding characteristics. The plasticizer is not particularly limited, and various known plasticizers of various systems can be widely used. As an example, low molecular compounds such as phthalates, adipates, phosphates, trimellitates, and citrates, polymers such as polyether-based, polyester-based, and polyacetal-based polymers described in JP-A 2013-253227 can be cited.

[0169] Furthermore, among the additives that endow the same filling / planarization characteristics as the plasticizer in the composition for forming an organic film of the present invention, it is preferable to use, for example, liquid additives having a polyethylene glycol or polypropylene glycol structure, or a thermal decomposable polymer having a weight reduction rate of 40% by mass or more between 30°C and 250°C and a weight average molecular weight of 300 to 200,000. It is more preferable that this thermal decomposable polymer contains repeating units having an acetal structure represented by the following general formulas (DP1) and (DP1a).

[0170] [Chemical formula 23]

[0171]

[0172] In the formula, R6 is a hydrogen atom or a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms which may be substituted. Y1 is a saturated or unsaturated divalent organic group having 2 to 30 carbon atoms.

[0173] [Chemical formula 24]

[0174]

[0175] In the formula, R 6a is an alkyl group having 1 to 4 carbon atoms. Y a is a saturated or unsaturated divalent hydrocarbon group having 4 to 10 carbon atoms, and may have an ether bond. n represents the average number of repeating units and is 3 to 500.

[0176] Furthermore, the composition for forming an organic film of the present invention can be used alone or in combination of two or more. This composition for forming an organic film can be used as an underlayer film material for a resist or a planarization material for manufacturing a semiconductor device.

[0177] Furthermore, the composition for forming an organic film of the present invention is extremely useful as an underlayer film material for a resist for a multi-layer resist process such as a two-layer resist process, a three-layer resist process using a silicon-containing intermediate layer film, or a four-layer resist process using a silicon-containing inorganic hard mask intermediate film and an organic antireflection film.

[0178] <Organic film forming method>

[0179] The present invention provides a method for forming an organic film that functions as an underlayer film of a multi-layer resist film for lithography or a planarization film for semiconductor manufacturing using the aforementioned composition for forming an organic film.

[0180] The method for forming an organic film of the present invention is to coat the composition for forming an organic film on a substrate to be processed by a spin coating method or the like. By using a spin coating method or the like, good filling characteristics can be obtained. After spin coating, the solvent is evaporated, and in order to prevent mixing with the upper resist film and the intermediate resist film, and in order to promote the crosslinking reaction, baking (heat treatment) is performed. The baking is preferably carried out in the range of 100°C or higher and 600°C or lower for 10 to 600 seconds, more preferably in the range of 200°C or higher and 500°C or lower for 10 to 300 seconds. Considering device damage and the influence on wafer deformation, the upper limit of the heating temperature in the wafer processing of lithography is preferably 600°C or lower, more preferably 500°C or lower.

[0181] Furthermore, the method for forming an organic film of the present invention can form an organic film by coating the composition for forming an organic film of the present invention on a substrate to be processed by the same spin coating method or the like as described above, and calcining the composition for forming an organic film in a gas environment with an oxygen concentration of 0.1% or more and 21% or less to harden it.

[0182] By calcining the composition for forming an organic film of the present invention in such an oxygen gas environment, a sufficiently hardened organic film can be obtained. The gas environment during baking can be air, but in order to reduce oxygen, it is more ideal to previously enclose inert gases such as N2, Ar, and He to prevent oxidation of the organic film. In order to prevent oxidation, it is advisable to control the oxygen concentration, preferably 1000 ppm or less, more preferably 100 ppm or less. If the oxidation of the organic film during baking is prevented, there will be no increase in absorption or decrease in etching resistance, which is more ideal.

[0183] Due to its excellent filling / planarization characteristics, the method for forming an organic film of the present invention can obtain a flat organic film regardless of the unevenness of the substrate to be processed, so it is extremely useful when forming a flat organic film on a substrate to be processed having a structure or height difference of 30 nm or more.

[0184] Furthermore, the thickness of the organic film such as the lower resist film or the planarization film for manufacturing a semiconductor device can be appropriately selected, preferably 30 to 20,000 nm, more preferably 50 to 15,000 nm.

[0185] (Pattern formation method)

[0186] The present invention provides a pattern forming method. As a pattern forming method using such a composition for forming an organic film and employing a three-layer resist process, a method for forming a pattern on a substrate to be processed includes at least the following steps: forming an organic film on the substrate to be processed using the composition for forming an organic film of the present invention; forming a silicon-containing resist underlayer film on the above-mentioned organic film using a silicon-containing resist underlayer film material; forming a resist upper layer film on the above-mentioned silicon-containing resist underlayer film using a photoresist composition; forming a circuit pattern on the above-mentioned resist upper layer film; using the resist upper layer film having the circuit pattern formed thereon as a mask to transfer the pattern to the above-mentioned silicon-containing resist underlayer film by etching; using the silicon-containing resist underlayer film having the pattern transferred thereon as a mask to transfer the pattern to the above-mentioned organic film by etching; and using the organic film having the pattern transferred thereon as a mask to form the pattern on the above-mentioned substrate to be processed.

[0187] The silicon-containing resist underlayer film in the above three-layer resist process shows etching resistance to oxygen or hydrogen. In the above three-layer resist process, it is preferably to use an etching gas mainly composed of oxygen or hydrogen to perform dry etching of the organic film with the silicon-containing resist underlayer film as a mask.

[0188] The silicon-containing resist underlayer film in the above three-layer resist process is preferably a polysiloxane-based underlayer film. By making the silicon-containing resist underlayer film have an antireflection effect, reflection can be suppressed. Especially for 193 nm exposure applications, if a material that contains many aromatic groups with respect to the organic film and has a high etching selectivity to the substrate is used, the k value increases and the substrate reflection increases. However, by making the silicon-containing resist underlayer film have an absorption that will result in an appropriate k value, reflection can be suppressed, and the substrate reflection can be made 0.5% or less. For the silicon-containing resist underlayer film having an antireflection effect, for 248 nm and 157 nm exposure applications, anthracene is preferably used, and for 193 nm exposure applications, a polysiloxane crosslinked by an acid or heat and having a pendant phenyl group or a light-absorbing group with a silicon-silicon bond is more ideal.

[0189] An organic anti-reflective film (BARC) may also be formed on the aforementioned silicon-containing resist underlayer film. In this case, a pattern can be formed on the workpiece by the steps of forming an organic film on the workpiece using the composition for forming an organic film of the present invention, forming a silicon-containing resist underlayer film on the aforementioned organic film using a silicon-containing resist underlayer film material, forming a BARC on the aforementioned silicon-containing resist underlayer film, forming a resist upper layer film on the aforementioned BARC using a photoresist composition, forming a circuit pattern on the aforementioned resist upper layer film, etching the aforementioned BARC and the aforementioned silicon-containing resist underlayer film in sequence using the aforementioned resist upper layer film having the formed circuit pattern as a mask to transfer the pattern, etching the aforementioned organic film using the aforementioned silicon-containing resist underlayer film having the transferred pattern as a mask to transfer the pattern, and etching the aforementioned workpiece using the aforementioned organic film having the transferred pattern as a mask to form a pattern on the aforementioned workpiece.

[0190] Alternatively, an inorganic hard mask may be formed as the resist underlayer film. In this case, a pattern can be formed on the workpiece by the steps of forming an organic film on the workpiece substrate using the composition for forming an organic film of the present invention, forming an inorganic hard mask selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the aforementioned organic film, forming a resist upper layer film on the aforementioned inorganic hard mask using a photoresist composition, forming a circuit pattern on the aforementioned resist upper layer film, etching the aforementioned inorganic hard mask using the aforementioned resist upper layer film having the formed circuit pattern as a mask to transfer the pattern, etching the aforementioned organic film using the aforementioned inorganic hard mask having the formed pattern as a mask to transfer the pattern, and etching the aforementioned workpiece using the aforementioned organic film having the formed pattern as a mask to form a pattern on the aforementioned workpiece.

[0191] As described above, when forming an inorganic hard mask on an organic film, a silicon oxide film, a silicon nitride film, and a silicon oxynitride film (SiON film) can be formed by a CVD method, an ALD method, or the like. For example, regarding the formation method of the silicon nitride film, it is described in Japanese Patent Laid-Open No. 2002-334869 and International Publication Pamphlet No. 2004 / 066377. The film thickness of the inorganic hard mask is preferably 5 to 200 nm, more preferably 10 to 100 nm. Further, the inorganic hard mask is preferably a SiON film having a high anti-reflection effect. In order to make the substrate temperature during the formation of the SiON film be 300 to 500 °C, the underlayer film needs to withstand a temperature of 300 to 500 °C. The composition for forming an organic film used in the present invention has high heat resistance and can withstand a high temperature of 300 °C to 500 °C. Therefore, it can be a combination of an inorganic hard mask formed by a CVD method or an ALD method and an organic film formed by a spin coating method.

[0192] Further, a four-layer resist process using BARC is also suitable. In this case, it is possible to form a pattern on the object to be processed through the steps of forming an organic film on the object to be processed using the composition for forming an organic film of the present invention, forming an inorganic hard mask selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the aforementioned organic film, forming BARC on the aforementioned inorganic hard mask, forming a resist upper layer film on the aforementioned BARC using a photoresist composition, forming a circuit pattern on the aforementioned resist upper layer film, using the resist upper layer film having the circuit pattern formed thereon as a mask to sequentially etch the aforementioned BARC and the aforementioned inorganic hard mask to transfer the pattern, using the inorganic hard mask having the pattern formed thereon as a mask and etching the aforementioned organic film to transfer the pattern, and using the organic film having the pattern formed thereon as a mask and etching the aforementioned object to be processed to form a pattern on the aforementioned object to be processed.

[0193] As described above, a photoresist film can be formed as a resist upper layer film on the inorganic hard mask, or BARC can be spin-coated on the inorganic hard mask and a photoresist film can be formed thereon. In particular, when using a SiON film as the inorganic hard mask, by using a two-layer antireflection film of SiON film and BARC, reflection can be suppressed even in immersion exposure with a high NA exceeding 1.0. Another advantage of forming BARC is that it can reduce the tailing of the photoresist pattern directly above the SiON film.

[0194] The resist upper layer film in the aforementioned three-layer resist process can be positive or negative, and the same photoresist composition as commonly used can be used. After spin-coating the photoresist composition, pre-baking is performed, and it is preferably in the range of 60 to 180 °C for 10 to 300 seconds. Then, exposure is performed according to the usual method, followed by post-exposure baking (PEB) and development to obtain a resist pattern. Also, the thickness of the resist upper layer film is not particularly limited, and 30 to 500 nm is more ideal, especially 50 to 400 nm is better.

[0195] Further, the exposure light can include high-energy rays with a wavelength of 300 nm or less, specifically, excimer lasers of 248 nm, 193 nm, 157 nm, soft X-rays of 3 to 20 nm, electron beams, X-rays, etc.

[0196] In the pattern formation method of the present invention, regarding the method of forming a circuit pattern on the aforementioned resist upper layer film, it is preferably to use lithography with a wavelength of 10 nm or more and 300 nm or less, direct drawing using an electron beam, nanoimprinting, or a combination thereof.

[0197] Further, in the pattern formation method of the present invention, the development method is preferably alkali development or development using an organic solvent.

[0198] The obtained resist pattern is then used as a mask for etching. For the etching of the silicon-containing resist underlayer film and the inorganic hard mask in the three-layer resist process, a fluorocarbon-based gas is used with the upper resist pattern as a mask. Thereby, a silicon-containing resist underlayer film pattern and an inorganic hard mask pattern are formed.

[0199] Next, the obtained silicon-containing resist underlayer film pattern and inorganic hard mask pattern are used as masks for the etching process of the organic film.

[0200] Etching of the workpieces such as the processed substrate after that can also be carried out according to the conventional method. For example, if the processed substrate is SiO2, SiN, or a silicon dioxide-based low dielectric constant insulating film, etching mainly using a flon-based gas is performed; for p-Si, Al, or W, etching mainly using a chlorine-based or bromine-based gas is performed. When etching the substrate with a flon-based gas, the silicon-containing resist underlayer film pattern in the three-layer resist process is peeled off simultaneously with the substrate processing. When etching the substrate with a chlorine-based or bromine-based gas, peeling of the silicon-containing resist underlayer film pattern needs to be additionally performed by dry etching using a flon-based gas after the substrate processing.

[0201] The organic film obtained using the composition for forming an organic film of the present invention has the characteristic of excellent etching resistance during etching of these processed substrates.

[0202] In the pattern formation method of the present invention, it is preferable to use a semiconductor device substrate, a metal film, a metal carbide film, a metal oxide film, a metal nitride film, a metal oxycarbide film, or a metal oxynitride film as the workpiece mentioned above.

[0203] Furthermore, it is preferable to use silicon, titanium, tungsten, hafnium, zirconium, chromium, germanium, copper, silver, gold, aluminum, indium, gallium, arsenic, palladium, iron, tantalum, iridium, molybdenum, or their alloys as the aforementioned metal.

[0204] Also, there is no particular limitation on the processed substrate, and substrates such as Si, α-Si, p-Si, SiO2, SiN, SiON, W, TiN, Al, etc., or those with a processed layer formed on the substrate can be used. As the processed layer, various Low-k films such as Si, SiO2, SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, Al-Si, etc., and their barrier films can be used. Generally, a thickness of preferably 50 to 10,000 nm, more preferably 100 to 5,000 nm can be formed. Also, when forming the processed layer, different materials can be used for the substrate and the processed layer.

[0205] Also, it is preferable to use a processed substrate having a structure or height difference of 30 nm or more as the processed substrate.

[0206] Regarding an example of the three-layer resist process, use Figure 1 Specifically, it is as follows.

[0207] In the case of a three-layer resist process, as Figure 1 (A), after forming an organic film 3 on a processed layer 2 laminated on a substrate 1 using the composition for forming an organic film of the present invention, a silicon-containing lower resist film 4 is formed, and an upper resist film 5 is formed thereon.

[0208] Next, as Figure 1 (B), a specific portion 6 of the upper resist film is exposed, PEB and development are performed to form a resist pattern 5a ( Figure 1 (C)). Using this obtained resist pattern 5a as a mask, the silicon-containing lower resist film 4 is etched using a CF-based gas to form a silicon-containing lower resist film pattern 4a ( Figure 1 (D)). After removing the resist pattern 5a, using this obtained silicon-containing lower resist film pattern 4a as a mask, the organic film 3 is etched by oxygen plasma to form an organic film pattern 3a ( Figure 1 (E)). Further, after removing the silicon-containing lower resist film pattern 4a, using the organic film pattern 3a as a mask, the processed layer 2 is etched to form a pattern 2a ( Figure 1 (F)).

[0209] When using an inorganic hard mask, the silicon-containing lower resist film 4 is an inorganic hard mask. When applying BARC, a BARC layer is provided between the silicon-containing lower resist film 4 or the inorganic hard mask and the upper resist film 5. The etching of BARC may sometimes be continuously performed before etching the silicon-containing lower resist film 4, or only the BARC may be etched and then the etching apparatus etc. may be changed and then the silicon-containing lower resist film 4 may be etched.

[0210] Thus, according to the pattern forming method of the present invention, a fine pattern can be formed with high precision on a processed substrate in a multi-layer resist process.

[0211] [Examples]

[0212] Hereinafter, examples and comparative examples will be given to specifically illustrate the present invention, but the present invention is not limited to these descriptions.

[0213] For the synthesis of polymers (A1) to (A8) contained in the composition for forming an organic film, the following fluorenols (B1) to (B4) and aromatic-containing compounds (C1) to (C3) are used.

[0214] Fluorenols:

[0215] [Chemical formula 25]

[0216]

[0217] Aromatic-containing compounds:

[0218] [Chemical formula 26]

[0219]

[0220] When synthesizing a polymer using a majority of fluorene alcohols, the feed ratio of these fluorene alcohols is as shown in the following formula, and is recorded using m and l.

[0221] [Chemical formula 27]

[0222]

[0223] (Synthesis Example 1)

[0224] Under a nitrogen atmosphere, 200 g of 1,2-dichloroethane was added to 30.0 g of fluorene alcohol (B1), and a homogeneous solution was prepared at an internal temperature of 50 °C. 15.8 g of methanesulfonic acid was slowly added, and the reaction was carried out at an internal temperature of 70 °C for 8 hours. After cooling to room temperature, 500 g of toluene was added, and it was washed 6 times with 100 g of pure water. The organic layer was dried under reduced pressure. 100 g of THF (tetrahydrofuran) was added to the residue to form a homogeneous solution, and then it was precipitated into 300 g of methanol. The precipitated crystals were filtered and separated, washed 2 times with 200 g of methanol, and recovered. The recovered crystals were dried in vacuo at 70 °C to obtain a polymer (A1) represented by the following formula. The weight average molecular weight (Mw) and dispersity (Mw / Mn) of the polymer (A1) obtained by GPC measurement using THF as the developing solvent and calculated using polystyrene conversion values were Mw = 2600 and Mw / Mn = 1.68.

[0225] [Chemical formula 28]

[0226]

[0227] (Synthesis Example 2)

[0228] Under a nitrogen atmosphere, 200 g of 1,2-dichloroethane was added to 30.0 g of fluorene alcohol (B2), and a homogeneous solution was prepared at an internal temperature of 50 °C. 12.4 g of methanesulfonic acid was slowly added, and the reaction was carried out at an internal temperature of 70 °C for 8 hours. After cooling to room temperature, 500 g of toluene was added, and it was washed 6 times with 100 g of pure water, and the organic layer was dried under reduced pressure. 100 g of THF was added to the residue to form a homogeneous solution, and then it was precipitated into 300 g of methanol. The precipitated crystals were filtered and separated, washed 2 times with 200 g of methanol, and recovered. The recovered crystals were dried in vacuo at 70 °C to obtain a polymer (A2) represented by the following formula. The weight average molecular weight (Mw) and dispersity (Mw / Mn) of the polymer (A2) obtained by GPC measurement using THF as the developing solvent and calculated using polystyrene conversion values were Mw = 2900 and Mw / Mn = 1.58.

[0229] [Chemical formula 29]

[0230]

[0231] (Synthesis Example 3)

[0232] Under a nitrogen atmosphere, 200 g of 1,2-dichloroethane was added to 30.0 g of fluorenol (B1) and 0.30 g of water, and a homogeneous solution was prepared at an internal temperature of 50°C. 15.8 g of methanesulfonic acid was slowly added, and the reaction was carried out at an internal temperature of 70°C for 8 hours. After cooling to room temperature, 500 g of toluene was added, and it was washed 6 times with 100 g of pure water. The organic layer was dried under reduced pressure. 100 g of THF was added to the residue to prepare a homogeneous solution, and then it was precipitated into 300 g of methanol. The precipitated crystals were filtered and separated, washed 2 times with 200 g of methanol and recovered. The recovered crystals were dried in vacuo at 70°C to obtain a polymer (A3) represented by the following formula. The weight-average molecular weight (Mw) and dispersity (Mw / Mn) of the polymer (A3) obtained by GPC measurement using THF as the eluent and calculated using polystyrene conversion values were Mw = 1800 and Mw / Mn = 1.49.

[0233] [Chemical Formula 30]

[0234]

[0235] (Synthesis Example 4)

[0236] Under a nitrogen atmosphere, 200 g of 1,2-dichloroethane was added to 30.0 g of fluorenol (B1) and 3.89 g of an aromatic compound (C1), and a homogeneous solution was prepared at an internal temperature of 50°C. 15.8 g of methanesulfonic acid was slowly added, and the reaction was carried out at an internal temperature of 70°C for 8 hours. After cooling to room temperature, 500 g of toluene was added, and it was washed 6 times with 100 g of pure water. The organic layer was dried under reduced pressure. 100 g of THF was added to the residue to prepare a homogeneous solution, and then it was precipitated into 300 g of methanol. The precipitated crystals were filtered and separated, washed 2 times with 200 g of methanol and recovered. The recovered crystals were dried in vacuo at 70°C to obtain a polymer (A4) represented by the following formula. The weight-average molecular weight (Mw) and dispersity (Mw / Mn) of the polymer (A4) obtained by GPC measurement using THF as the eluent and calculated using polystyrene conversion values were Mw = 1520 and Mw / Mn = 1.48.

[0237] [Chemical Formula 31]

[0238]

[0239] (Synthesis Example 5)

[0240] Under a nitrogen atmosphere, 30.0 g of fluorenol (B1) and 2.75 g of an aromatic compound (C2) were added to 200 g of 1,2-dichloroethane, and a homogeneous solution was prepared at an internal temperature of 50 °C. 15.8 g of methanesulfonic acid was slowly added, and the reaction was carried out at an internal temperature of 70 °C for 8 hours. After cooling to room temperature, 500 g of toluene was added, and washing was carried out 6 times with 100 g of pure water. The organic layer was dried under reduced pressure. 100 g of THF was added to the residue, and after a homogeneous solution was prepared, precipitation was carried out in 300 g of methanol. The precipitated crystals were filtered and separated, washed twice with 200 g of methanol and recovered. The recovered crystals were vacuum-dried at 70 °C to obtain a polymer (A5) represented by the following formula. The weight-average molecular weight (Mw) and dispersity (Mw / Mn) of the polymer (A5) obtained using polystyrene conversion values determined by GPC measurement with THF as the eluent were Mw = 1420 and Mw / Mn = 1.53.

[0241] [Chemical formula 32]

[0242]

[0243] (Synthesis Example 6)

[0244] Under a nitrogen atmosphere, 30.0 g of fluorenol (B2) and 5.82 g of an aromatic compound (C3) were added to 200 g of 1,2-dichloroethane, and a homogeneous solution was prepared at an internal temperature of 50 °C. 12.4 g of methanesulfonic acid was slowly added, and the reaction was carried out at an internal temperature of 70 °C for 8 hours. After cooling to room temperature, 500 g of toluene was added, and washing was carried out 6 times with 100 g of pure water. The organic layer was dried under reduced pressure. 100 g of THF was added to the residue, and after a homogeneous solution was prepared, precipitation was carried out in 300 g of methanol. The precipitated crystals were filtered and separated, washed twice with 200 g of methanol and recovered. The recovered crystals were vacuum-dried at 70 °C to obtain a polymer (A6) represented by the following formula. The weight-average molecular weight (Mw) and dispersity (Mw / Mn) of the polymer (A6) obtained using polystyrene conversion values determined by GPC measurement with THF as the eluent were Mw = 1720 and Mw / Mn = 1.38.

[0245] [Chemical formula 33]

[0246]

[0247] (Synthesis Example 7)

[0248] Under a nitrogen atmosphere, 200 g of 1,2-dichloroethane was added to 15.0 g of fluorenol (B1) and 18.1 g of fluorenol (B3), and a homogeneous solution was prepared at an internal temperature of 50 °C. 15.8 g of methanesulfonic acid was slowly added, and the reaction was carried out at an internal temperature of 70 °C for 8 hours. After cooling to room temperature, 500 g of toluene was added, and it was washed 6 times with 100 g of pure water. The organic layer was dried under reduced pressure. 100 g of THF was added to the residue, and after preparing a homogeneous solution, it was precipitated into 300 g of methanol. The precipitated crystals were filtered and separated, washed 2 times with 200 g of methanol and recovered. The recovered crystals were dried under vacuum at 70 °C to obtain a polymer (A7) represented by the following formula. The weight-average molecular weight (Mw) and dispersity (Mw / Mn) of the polymer (A7) obtained using polystyrene conversion values determined by GPC measurement with THF as the developing solvent were Mw = 2430 and Mw / Mn = 1.74.

[0249] [Chemical formula 34]

[0250]

[0251] (Synthesis Example 8)

[0252] Under a nitrogen atmosphere, 100 g of 1,2-dichloroethane was added to 10.0 g of fluorenol (B4), and a homogeneous solution was prepared at an internal temperature of 50 °C. 15.8 g of methanesulfonic acid was slowly added, and the reaction was carried out at an internal temperature of 70 °C for 4 hours. After that, after cooling to an internal temperature of 50 °C, a mixture of 21.0 g of fluorenol (B2) and 100 g of 1,2-dichloroethane that had been previously homogenized was slowly added dropwise. The temperature was raised again to an internal temperature of 70 °C, and the reaction was carried out for 8 hours. After cooling to room temperature, 500 g of toluene was added, and it was washed 6 times with 100 g of pure water. The organic layer was dried under reduced pressure. 100 g of THF was added to the residue, and after preparing a homogeneous solution, it was precipitated into 300 g of methanol. The precipitated crystals were filtered and separated, washed 2 times with 200 g of methanol and recovered. The recovered crystals were dried under vacuum at 70 °C to obtain a polymer (A8) represented by the following formula. The weight-average molecular weight (Mw) and dispersity (Mw / Mn) of the polymer (A8) obtained using polystyrene conversion values determined by GPC measurement with THF as the developing solvent were Mw = 2930 and Mw / Mn = 1.61.

[0253] [Chemical formula 35]

[0254]

[0255] (Comparative Synthesis Example)

[0256] Under a nitrogen atmosphere, 12.8 g of naphthalene and 18.0 g of 9-fluorenone were added, the temperature was raised to 230°C, and the reaction was carried out for 8 hours. From the beginning of the reaction, 0.25 ml of methanesulfonic acid was added to the reaction solution every 1 hour, for a total of 8 times. After cooling to room temperature, 40 g of toluene was added to the reaction solution, and the solution was washed with pure water 6 times. The organic layer was dried under reduced pressure. 100 g of THF (tetrahydrofuran) was added to the residue to make a uniform solution, which was then precipitated in 300 g of methanol. The precipitated crystals were filtered and separated, washed twice with 200 g of methanol and recovered. The recovered crystals were vacuum dried at 70°C to obtain a polymer (R1) represented by the following formula. The weight average molecular weight (Mw) and dispersity (Mw / Mn) of the polymer (R1) obtained by GPC measurement using THF as the developing solvent were Mw = 2130 and Mw / Mn = 2.61, respectively.

[0257] [Chemistry 36]

[0258]

[0259] Table 1 shows a list of the structural formulas, Mw, and Mw / Mn results of polymers (A1) to (A8) used in Examples and polymer (R1) used in Comparative Examples.

[0260] [Table 1]

[0261]

[0262] Preparation of organic film-forming compositions (UDL-1 to 12, comparative UDL 1 to 2)

[0263] The polymers (A1) to (A8) and (R1) were dissolved in propylene glycol monomethyl ether acetate (PGMEA) or cyclohexanone (CyHO) containing 0.1% by mass of FC-4430 (manufactured by Sumitomo 3M Co., Ltd.) in the ratios shown in Table 2, along with (S1) 1,6-diacetoxyhexane (boiling point 260°C) and (S2) tripropylene glycol monomethyl ether (boiling point 242°C) as high-boiling-point solvents. The mixtures were then filtered through a 0.1 μm fluororesin filter to prepare organic film-forming compositions (UDL-1 to 12 and Comparative UDL-1 to 2). The comparative UDLs used the following formulae: an acid generator (AG) and a crosslinking agent (XL).

[0264] [Table 2]

[0265]

[0266] [Chemistry 37]

[0267]

[0268] Examples 1-1 to 1-12, Comparative Examples 1-1 to 1-2 (Solvent Resistance Measurement)

[0269] The foregoing UDL-1 to 12 and Comparative UDL-1 to 2 were coated on a silicon substrate, baked in the atmosphere at 350 °C for 60 seconds, and then the film thickness was measured. PGMEA solvent was dropped thereon, spun dry after standing for 30 seconds, and baked at 100 °C for 60 seconds to evaporate PGMEA, and the film thickness before and after PGMEA treatment was measured. The residual film rate was calculated using the film thickness after film formation and the film thickness after PGMEA treatment. The results are shown in Table 3.

[0270] [Table 3]

[0271]

[0272] As shown in Table 3, for the organic films (Examples 1-1 to 1-12) using the polymer of the present invention, the residual film rate after PGMEA treatment was 99% or more. It can be seen that a crosslinking reaction occurred due to heat treatment, showing sufficient solvent resistance. For Comparative UDL-1 using the polymer (R1), since there is no crosslinking site, the polymer alone does not show solvent resistance, and an acid generator and a crosslinking agent need to be added to show solvent resistance. From these results, it can be known that a partial structure of the polymer of the present invention can effectively act as a thermal crosslinking group.

[0273] Examples 2-1 to 2-12, Comparative Examples 2-1 to 2-2 (Hardness Measurement)

[0274] [[ID=z18]]The foregoing UDL-1 to 12 and Comparative UDL-1 to 2 were coated on a silicon substrate and baked in the atmosphere at 350 °C for 60 seconds to form an organic film with a film thickness of 200 nm. Such an organic film was subjected to a nanoindentation test using a nanoindentation instrument SA2 type manufactured by TOYO Corporation to measure the hardness of the foregoing organic film. The results are shown in Table 4.

[0275] [Table 4]

[0276] Composition for Forming Organic Film Hardness (GPa) Example 2-1 UDL-1 0.65 Example 2-2 UDL-2 0.69 Example 2-3 UDL-3 0.66 Example 2-4 UDL-4 0.68 Example 2-5 UDL-5 0.63 Example 2-6 UDL-6 0.64 Example 2-7 UDL-7 0.68 Example 2-8 UDL-8 0.70 Example 2-9 UDL-9 0.66 Example 2-10 UDL-10 0.69 Example 2-11 UDL-11 0.64 Example 2-12 UDL-12 0.66 Comparative Example 2-1 Comparative UDL-1 0.45 Comparative Example 2-2 Comparative UDL-2 0.48

[0277] As can be confirmed from Table 4, in Examples 2-1 to 2-12, the hardness was greater than that in Comparative Examples 2-1 to 2-2. The polymer of the present invention can form a denser and higher-strength organic film compared to the polymers (R1) used in Comparative UDL-1 and -2. The reason is that the polymer of the present invention has thermosetting properties, so the hardened organic film can form a dense organic film composed only of condensed aromatic rings with a high carbon density, resulting in high hardness. On the contrary, for the polymer (R1) used in the comparative example, although the carbon density is high, the polymer itself does not have thermosetting properties, so the hardness of the organic film is not a high value. Also, although the polymer (R1) can show solvent resistance by using a crosslinking agent, since the crosslinking agent will damage the carbon density of the polymer, even after forming a hardened organic film, a significant increase in hardness cannot be obtained.

[0278] Examples 3-1 to 3-12, Comparative Examples 3-1 to 3-2 (Etching Test)

[0279] [Etching Test Using CF4 / CHF3-Based Gas]

[0280] The aforementioned UDL-1 to 12 and Comparative UDL-1 to 2 were coated on a silicon substrate and baked in the atmosphere at 350 °C for 60 seconds to form an organic film with a film thickness of 200 nm. Then, an etching test using CF4 / CHF3-based gas was carried out under the following conditions. In this case, a dry etching apparatus TE-8500 manufactured by Tokyo Electron Limited was used to obtain the film thickness difference of the organic film before and after etching. The results are shown in Table 5.

[0281] The etching conditions are as follows.

[0282]

[0283]

[0284] [Table 5]

[0285]

[0286] In Table 5, the film reduction ratios of the Examples and Comparative Examples are expressed when the film thickness reduction of Comparative UDL-1 due to etching with CF4 / CHF3-based gas is set to 100. The smaller this ratio, the more excellent the etching resistance.

[0287] [Etching Test Using O2-Based Gas] [[ID=3,1]]

[0288] The aforementioned UDL-1 to 12 and Comparative UDL-1 to 2 were coated on a silicon substrate and baked in the atmosphere at 350 °C for 60 seconds in an air gas environment to form an organic film with a film thickness of 200 nm. Then, an etching test using O2-based gas was carried out under the following conditions. In this case, a dry etching apparatus TE-8500 manufactured by Tokyo Electron Limited was used to obtain the film thickness difference of the polymer film before and after etching. The results are also shown in Table 5.

[0289] The etching conditions are as follows.

[0290]

[0291] Similar to the etching test using CF4 / CHF3-based gas, in Table 5, the film reduction ratios of the Examples and Comparative Examples are expressed when the film thickness reduction of Comparative UDL-1 due to etching with O2-based gas is set to 100. The smaller this ratio, the more excellent the etching resistance.

[0292] As shown in Table 5, when comparing Examples 3-1 to 3-12 with Comparative Examples 3-1 to 3-2, in the etching tests of CF4 / CHF3-based gases and O2-based gases, the reduction amounts after etching of the organic films in Examples 3-1 to 3-12 are smaller than those after etching of the organic films in Comparative UDL-1 to 2. It can be seen that an organic film with excellent etching resistance is formed. Also, when comparing Comparative Example 3-1 with 3-2, in Comparative Example 3-2 where a crosslinking agent is used to form an organic film, due to the addition of the crosslinking agent, the carbon content of the organic film decreases, and as a result, about 10% of the etching resistance is lost. Further, when comparing Examples 3-1 to 3-12 using the polymer of the present invention with Comparative Example 3-1 of Comparative Polymer (R1), as inspired by the results of hardness measurement, Examples 3-1 to 3-12 using the polymer of the present invention become dense organic films due to thermal crosslinking. Therefore, compared with Comparative Example 3-1, the reduction amount of the organic film thickness after etching is suppressed by more than 5%, and the etching resistance of the organic film formed using the composition for forming an organic film of the present invention is more excellent.

[0293] Examples 4-1 to 4-12, Comparative Examples 4-1 to 4-2 (pattern etching test)

[0294] The aforementioned UDL1-1 to 1-12 and Comparative UDL1-1 to 1-2 were coated on a 300-mm-diameter Si wafer substrate with a 200-nm-thick SiO2 film formed thereon. After baking in the atmosphere at 350 °C for 60 seconds, an anti-reflective lower layer film was formed to make the film thickness 200 nm. A silicon-containing anti-reflective intermediate layer material (SOG-1) was coated thereon, baked at 220 °C for 60 seconds, and an anti-reflective intermediate layer film with a thickness of 35 nm was formed. An anti-reflective upper layer film material (ArF SL resist) was coated, baked at 105 °C for 60 seconds, and an anti-reflective upper layer film with a thickness of 100 nm was formed. A wetting protection film (TC-1) was coated on the anti-reflective upper layer film, baked at 90 °C for 60 seconds, and a protection film with a thickness of 50 nm was formed.

[0295] Regarding the anti-reflective upper layer film material (ArF SL resist), 100 parts by mass of the polymer (RP1) represented by the following formula, 6.6 parts by mass of the acid generator (PAG1) represented by the following formula, and 0.8 parts by mass of the basic compound (Amine1) represented by the following formula were dissolved in 2500 parts by mass of PGMEA containing 0.1 mass% of FC-430 (manufactured by Sumitomo 3M Co., Ltd.) and filtered through a 0.1-μm fluororesin filter to prepare.

[0296] [Chemical Formula 38]

[0297]

[0298] Regarding the infiltration protective film material (TC-1), it is prepared by dissolving 100 parts by mass of a protective film polymer (PP1) represented by the following formula in an organic solvent composed of 2700 parts by mass of diisopentyl ether and 270 parts by mass of 2-methyl-1-butanol, and filtering through a fluororesin filter with a pore size of 0.1 μm.

[0299] [Chemical formula 39]

[0300]

[0301] The silicon-containing resist intermediate layer material (SOG-1) is prepared by dissolving 100 parts by mass of an ArF silicon-containing intermediate film polymer (SiP1) represented by the following formula and 1 part by mass of a crosslinking catalyst (CAT1) represented by the following formula in 4000 parts by mass of PGMEA containing 0.1 mass% of FC-4430 (manufactured by Sumitomo 3M Limited), and filtering through a fluororesin filter with a pore size of 0.1 μm.

[0302] [Chemical formula 40]

[0303]

[0304] Next, it is exposed using an ArF immersion exposure apparatus (manufactured by Nikon Corporation; NSR-S610C, NA 1.30, σ 0.98 / 0.65, 35-degree dipole s-polarized illumination, 6% half-tone phase shift mask) while changing the exposure amount, baked at 100 °C for 60 seconds (PEB), and developed with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) for 30 seconds to obtain a positive line-and-space pattern with a pitch of 100 nm and a resist line width of 50 nm to 30 nm.

[0305] After that, using the etching apparatus Telius manufactured by Tokyo Electron Limited, the silicon-containing intermediate layer is processed by dry etching using the resist pattern as a mask, the lower layer film is processed using the silicon-containing intermediate layer as a mask, and the SiO2 film is processed using the lower layer film as a mask, in sequence.

[0306] The etching conditions are as follows.

[0307] Conditions for transferring the resist pattern to the SOG film:

[0308]

[0309] Conditions for transferring the SOG film to the lower layer film:

[0310]

[0311] Conditions for transferring to the SiO2 film:

[0312]

[0313] The pattern cross-section was observed with a Hitachi, Ltd. electron microscope (S-4700) and the shapes were compared, and the results are summarized in Table 6.

[0314] [Table 6]

[0315]

[0316] As shown in Table 6, according to the results of Examples 4-1 to 4-12, when UDL-1 to 12 were used as the underlayer film of the three-layer resist for immersion lithography, the shape of the resist after development in the pattern shape evaluation was good, and it was known to have a useful effect as an antireflection film. On the contrary, in Comparative Example 4-1, since Comparative UDL-1 was used, it had no thermosetting property and no solvent resistance, so the film dissolved when the silicon-containing resist intermediate layer material (SOG-1) was coated, and a pattern could not be formed. In Comparative Example 4-2 using Comparative UDL-2, a resist pattern could be formed, so the pattern shapes after etching were compared.

[0317] In the pattern shapes after etching, in Examples 4-1 to 4-12, the shapes of the resist after development, after oxygen etching, and of the underlayer film after substrate processing etching were all good. According to the resist line width produced by exposure, the pattern size after substrate transfer also changed. In Comparative Example 4-2, pattern distortion occurred at a line width of about 40 nm, but in Examples 4-1 to 4-12 using the polymer of the present invention, there was no distortion in the pattern size up to 35 nm or less. It was found that the organic film formed from the composition for forming an organic film containing the polymer of the present invention had high distortion resistance. It was understood that by using a polymer such as the polymer of the present invention, a dense and high-strength organic film with a hardness exceeding 0.60 GPa as the underlayer film of the resist, higher distortion resistance could be obtained.

[0318] Examples 5-1 to 5-12 (filling characteristics)

[0319] On a SiO2 substrate with a height difference pattern of SiO2 having a thickness of 500 nm and formed with dense holes having a diameter of 160 nm, UDL-1 to 12 were coated under the condition that a film thickness of 80 nm would be formed on a flat substrate after baking at 350 °C for 60 seconds to form an underlayer film of the resist. The substrate on which the underlayer film of the resist had been formed was cut, and a scanning electron microscope (SEM) was used to observe whether the underlayer film of the resist had filled to the bottom of the holes. The results are shown in Table 7.

[0320] [Table 7]

[0321] Bottom Anti-Reflective Coating Material Filling Property Example 5-1 UDL-1 Filled Well to the Bottom of the Hole Example 5-2 UDL-2 Filled Well to the Bottom of the Hole Example 5-3 UDL-3 Filled Well to the Bottom of the Hole Example 5-4 UDL-4 Filled Well to the Bottom of the Hole Example 5-5 UDL-5 Filled Well to the Bottom of the Hole Example 5-6 UDL-6 Filled Well to the Bottom of the Hole Example 5-7 UDL-7 Filled Well to the Bottom of the Hole Example 5-8 UDL-8 Filled Well to the Bottom of the Hole Example 5-9 UDL-9 Filled Well to the Bottom of the Hole Example 5-10 UDL-10 Filled Well to the Bottom of the Hole Example 5-11 UDL-11 Filled Well to the Bottom of the Hole Example 5-12 UDL-12 Filled Well to the Bottom of the Hole

[0322] As shown in Table 7, in Examples 5-1 to 5-12 where the UDL-1 to UDL-12 of the present invention were used to form the underlayer film of the resist, all could be well filled to the bottom of the holes, and sufficient filling characteristics could be expected even when there were height differences on the substrate to be processed, indicating that it has useful characteristics as a material for the underlayer film of the resist for multilayer processing.

[0323] Examples 6-1 to 6-4, Comparative Examples 6-1 to 6-2 (Planarization characteristics)

[0324] The composition for forming an organic film (UDL-1, 3, 11, 12, Comparative UDL-1, 2) was respectively coated on a SiO2 wafer substrate with a large isolated trench pattern (trench width 10 μm, trench depth 0.10 μm). After calcination in the atmosphere at 350 °C for 60 seconds, the height difference (delta in Figure 2 ) between the organic film in the trench part and the non-trench part was observed using an NX10 atomic force microscope (AFM) manufactured by Park Systems Corporation. The results are shown in Table 8. In this evaluation, the smaller the height difference, the better the planarization characteristics can be said to be. Also, in this evaluation, a trench pattern with a depth of 0.10 μm is usually planarized using a composition for forming an organic film with a film thickness of about 0.2 μm. In order to evaluate the superiority and inferiority of the planarization characteristics, strict evaluation conditions were adopted.

[0325] [Table 8] <UNK>

[0326] Bottom Anti-Reflective Coating Material Height Difference (nm) Example 6-1 UDL-1 75 Example 6-2 UDL-3 70 Example 6-3 UDL-11 65 Example 6-4 UDL-12 65 Comparative Example 6-1 Comparative UDL-1 90 Comparative Example 6-2 Comparative UDL-2 90

[0327] As shown in Table 8, for the composition for forming an organic film of the present invention, the height difference between the organic film in the trench part and the non-trench part is small compared to Comparative Example 6-1 and Comparative Example 6-2, and excellent planarization characteristics are confirmed. It is speculated that the film density of Comparative Example 6-1 and Comparative Example 6-2 is poor, so the film loss caused by baking increases, and thus the film thickness difference between the upper part and the lower part of the height difference becomes more prominent after baking, resulting in poor flatness. Also, when Examples 6-3 and 6-4 with high-boiling solvents added are compared with Examples 6-1 and 6-2 without addition, it can be seen that the flatness is improved by adding high-boiling solvents.

[0328] As described above, the composition for forming an organic film of the present invention has high etching resistance and excellent resistance to distortion during etching, and can be used for multilayer resist processing for ultra-fine and high-precision pattern processing. In particular, the underlayer film for three-layer resist processing is a very useful organic film.

[0329] Also, the present invention is not limited to the above embodiments. The above embodiments are illustrative, and all those having substantially the same constitution and the same effects as the technical idea of the claims of the present invention are included in the technical scope of the present invention.

[0330] Symbol description

[0331] 1: Substrate

[0332] 2: Layer to be processed

[0333] 2a: Pattern of the layer to be processed

[0334] 3: Organic film

[0335] 3a: Pattern of the organic film

[0336] 4: Silicon-containing anti-reflective underlayer film

[0337] 4a: Pattern of the silicon-containing anti-reflective underlayer film

[0338] 5: Anti-reflective upper layer film

[0339] 5a: Pattern of the anti-reflective film

[0340] 6: Specific part

Claims

1. A composition for forming an organic film, characterized by containing a polymer having a partial structure represented by the following general formula (1A) and an organic solvent; In the general formula (1A), Ar1 and Ar2 are benzene rings or naphthalene rings which may have substituents, In addition, the polymer further has a partial structure represented by the following general formula (1B); In the general formula (1B), W1 is an alkoxy group having 1 to 10 carbon atoms or an organic group having one or more aromatic rings which may have substituents, and Ar1 and Ar2 are benzene rings or naphthalene rings which may have substituents.

2. The composition for forming an organic film according to claim 1, wherein the polymer further has a partial structure represented by the following general formula (1C); In the general formula (1C), W2 represents a monovalent organic group having 1 to 50 carbon atoms, and Ar1 and Ar2 are benzene rings or naphthalene rings which may have substituents.

3. The composition for forming an organic film according to claim 1 or 2, wherein The weight average molecular weight of the polymer is 500 to 5000.

4. The composition for forming an organic film according to claim 1 or 2, wherein The organic solvent is a mixture of one or more organic solvents with a boiling point below 180°C and one or more organic solvents with a boiling point of 180°C or higher.

5. The composition for forming an organic film according to claim 1 or 2, wherein, The composition for forming an organic film further contains one or more of a surfactant and a plasticizer.

6. A pattern forming method, characterized by including the following steps: Forming an organic film on a workpiece using the composition for forming an organic film according to any one of claims 1 to 5; Forming a silicon-containing anti-reflective coating underlayer film on the organic film using a silicon-containing anti-reflective coating underlayer film material; Forming an anti-reflective coating upper layer film on the silicon-containing anti-reflective coating underlayer film using a photoresist composition; Forming a circuit pattern on the anti-reflective coating upper layer film; Using the anti-reflective coating upper layer film with the formed circuit pattern as a mask, and transferring the pattern to the silicon-containing anti-reflective coating underlayer film by etching; Using the silicon-containing anti-reflective coating underlayer film with the transferred pattern as a mask, and transferring the pattern to the organic film by etching; Using the organic film with the transferred pattern as a mask, and forming a pattern on the workpiece by etching.

7. A pattern forming method, characterized by including the following steps: Forming an organic film on a workpiece using the composition for forming an organic film according to any one of claims 1 to 5; Forming a silicon-containing anti-reflective coating underlayer film on the organic film using a silicon-containing anti-reflective coating underlayer film material; Forming an organic anti-reflective coating BARC on the silicon-containing anti-reflective coating underlayer film; Forming an anti-reflective coating upper layer film on the BARC using a photoresist composition; Forming a circuit pattern on the anti-reflective coating upper layer film; Using the anti-reflective coating upper layer film with the formed circuit pattern as a mask, and transferring the pattern to the BARC and the silicon-containing anti-reflective coating underlayer film in sequence by etching; Using the silicon-containing anti-reflective coating underlayer film with the transferred pattern as a mask, and transferring the pattern to the organic film by etching; Using the organic film with the transferred pattern as a mask, and etching the workpiece to form a pattern on the workpiece.

8. A pattern forming method, characterized by including the following steps: Forming an organic film on a workpiece using the composition for forming an organic film according to any one of claims 1 to 5; An inorganic hard mask selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film is formed on the organic film; A resist upper layer film is formed on the inorganic hard mask using a photoresist composition; A circuit pattern is formed on the resist upper layer film; Using the resist upper layer film on which the circuit pattern has been formed as a mask, the pattern is transferred to the inorganic hard mask by etching; Using the inorganic hard mask on which the pattern has been formed as a mask, the pattern is transferred to the organic film by etching; Using the organic film on which the pattern has been formed as a mask, the workpiece is etched to form a pattern on the workpiece.

9. A pattern forming method, characterized by comprising the following steps: An organic film is formed on a workpiece using the organic film forming composition according to any one of claims 1 to 5; An inorganic hard mask selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film is formed on the organic film; A BARC is formed on the inorganic hard mask; A resist upper layer film is formed on the BARC using a photoresist composition; A circuit pattern is formed on the resist upper layer film; Using the resist upper layer film on which the circuit pattern has been formed as a mask, the pattern is sequentially transferred to the BARC and the inorganic hard mask by etching; Using the inorganic hard mask on which the pattern has been formed as a mask, the pattern is transferred to the organic film by etching; Using the organic film on which the pattern has been formed as a mask, the workpiece is etched to form a pattern on the workpiece.

10. The pattern forming method according to claim 8 or 9, wherein The inorganic hard mask is formed by CVD method or ALD method.

11. The pattern forming method according to any one of claims 6 to 9, wherein, Regarding the method of forming a circuit pattern on the resist upper layer film, lithography with a wavelength of 10 nm or more and 300 nm or less, direct drawing using an electron beam, nanoimprinting, or a combination thereof is used.

12. The pattern forming method according to any one of claims 6 to 9, wherein, Regarding the developing method, alkali development or development using an organic solvent is used.

13. The pattern forming method according to any one of claims 6 to 9, wherein, Regarding the workpiece, a semiconductor device substrate, a metal film, a metal carbide film, a metal oxide film, a metal nitride film, a metal oxycarbide film, or a metal oxynitride film is used.

14. The pattern forming method according to claim 13, wherein, Regarding the metal, titanium, tungsten, hafnium, zirconium, chromium, germanium, copper, silver, gold, aluminum, indium, gallium, palladium, iron, tantalum, iridium, molybdenum, or their alloys are used.

15. A polymer, characterized by having a partial structure represented by the following general formula (1A); In the above general formula (1A), Ar1 and Ar2 are benzene rings or naphthalene rings which may have substituents, In addition, the polymer further has a partial structure represented by the following general formula (1B); In the above general formula (1B), W1 is an alkoxy group having 1 to 10 carbon atoms or an organic group having one or more aromatic rings which may have substituents, and Ar1 and Ar2 are benzene rings or naphthalene rings which may have substituents.

16. The polymer according to claim 15, wherein, The polymer further has a partial structure represented by the following general formula (1C); In the general formula (1C), W2 represents a monovalent organic group having 1 to 50 carbon atoms, and Ar1 and Ar2 are benzene rings or naphthalene rings which may have substituents.

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