Cleaning solution, substrate cleaning method, and metal-containing film forming method

Abstract

To provide a cleaning solution that has excellent cleaning properties, such as for removing a metal-containing film from the peripheral edge of a substrate when a metal-containing film-forming composition is applied to the substrate, as well as hump suppression and drainage stability, a method for cleaning a semiconductor substrate using the same, and a method for forming a metal-containing film using the same cleaning method.SOLUTION: A cleaning solution for a metal-containing film-forming composition includes (A) a solvent and (B) an organic acid, and the solvent (A) includes at least one first solvent (A-1) having a standard boiling point of less than 160°C, and at least one second solvent (A-2) having a standard boiling point of 160°C or higher but lower than 500°C.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cleaning liquid, a method for cleaning a substrate, and a method for forming a metal-containing film, and more particularly to a cleaning liquid for a metal-containing film-forming composition that can be used in a microfabrication process for a semiconductor device or the like, a method for cleaning a semiconductor substrate, and a method for forming a resist underlayer film. [Background technology]

[0002] As LSIs become more highly integrated and faster, pattern dimensions are becoming increasingly fine. Lithography technology has achieved this by shortening the wavelength of light sources and selecting appropriate resist compositions to match. Single-layer positive photoresist compositions have become the key to this. These single-layer positive photoresist compositions incorporate a backbone that provides etching resistance to dry etching with chlorine- or fluorine-based gas plasma, and a switching mechanism that dissolves exposed areas. This allows the exposed areas to be dissolved to form a pattern, and the remaining resist pattern is then used as an etching mask to dry etch the substrate.

[0003] However, if the thickness of the photoresist film used is made finer, i.e., the pattern width is made smaller, the resolution of the photoresist film decreases, and when an attempt is made to develop the photoresist film into a pattern using a developer, the aspect ratio becomes too large, resulting in pattern collapse. For this reason, photoresist films have been made thinner as patterns become finer.

[0004] On the other hand, substrate processing typically involves dry etching using a patterned photoresist film as an etching mask. However, in reality, no dry etching method can achieve perfect etching selectivity between the photoresist film and the substrate. As a result, the photoresist film can be damaged and disintegrated during substrate processing, preventing accurate transfer of the resist pattern to the substrate. Therefore, as patterns become finer, resist compositions are required to have higher dry etching resistance. However, to improve resolution, resins used in photoresist compositions must have low light absorption at the exposure wavelength. As a result, as exposure light wavelengths have become shorter (i-line, KrF, and ArF), resins have evolved, such as novolac resins, polyhydroxystyrenes, and resins with aliphatic polycyclic skeletons. However, in reality, the etching rates under dry etching conditions during substrate processing have become faster, and recent photoresist compositions with high resolution tend to have weaker etching resistance.

[0005] This means that substrates to be processed must be dry etched using thinner photoresist films with weaker etching resistance, and there is an urgent need to secure the materials and processes required for this processing step.

[0006] One method for solving these problems is the multilayer resist method, in which a resist intermediate film having an etching selectivity different from that of a photoresist film (i.e., a resist upper layer film) is interposed between the resist upper layer film and the substrate to be processed, a pattern is formed on the resist upper layer film, and then the pattern is transferred to the resist intermediate film by dry etching using the resist upper layer film pattern as a dry etching mask, and the pattern is further transferred to the substrate to be processed by dry etching using the resist intermediate film as a dry etching mask.

[0007] One type of multilayer resist method is the three-layer resist method, which can be performed using a typical resist composition used in single-layer resist methods. In this three-layer resist method, for example, an organic film made of a novolac resin or the like is deposited on a substrate to be processed as a resist underlayer, a silicon-containing resist intermediate film is deposited on top of that as a resist intermediate film, and a conventional organic photoresist film is deposited on top of that as a resist upper layer. When dry etching is performed using a fluorine-based gas plasma, the organic resist upper layer exhibits a favorable etching selectivity relative to the silicon-containing resist intermediate film, allowing the resist upper layer pattern to be transferred to the silicon-containing resist intermediate film by dry etching with a fluorine-based gas plasma. This method allows for pattern transfer to the silicon-containing resist intermediate film (resist intermediate film) even when using a resist composition that is difficult to directly form a pattern with a sufficient thickness for processing the substrate or that does not have sufficient dry etching resistance for substrate processing. Subsequent pattern transfer by dry etching with an oxygen- or hydrogen-based gas plasma allows for the formation of a pattern in an organic film (resist underlayer) made of a novolac resin or the like that has sufficient dry etching resistance for substrate processing. Many resist underlayer films such as those described above are already known, for example, those described in Patent Document 1.

[0008] On the other hand, in recent years, the miniaturization of DRAM memories has accelerated, and there is an increasing need for resist underlayer films that have further improved dry etching resistance and excellent filling and planarization properties. Coating-type organic underlayer film materials that have excellent filling and planarization properties have been reported, for example, as described in Patent Document 2. However, in terms of application to advanced generations, there are concerns about dry etching resistance, and the application limits of conventional coating-type organic underlayer film materials are approaching.

[0009] To address the above-mentioned issues, development of a resist underlayer film using a material containing a metal element has been investigated. By baking, the ligands attached to the metal in the metal-containing film-forming composition are thermally decomposed, hydrolysis and condensation proceed, and a metal oxide is formed, resulting in the formation of a resist underlayer film with excellent dry etching resistance. Patent Document 3 reports that a material using a Ti compound exhibits excellent dry etching resistance against CHF3 / CF4-based gas and CO2 / N2-based gas.

[0010] When a metal-containing film-forming composition is used for a resist underlayer film, there is a risk that when the metal-containing film-forming composition is applied to a substrate, the metal compound may bond to the surface of the substrate, such as a silicon wafer, and leave residue. To remove such residue, it has been proposed to use a cleaning solution containing an organic solvent and a carboxylic acid (Patent Document 4). Patent Document 5 also proposes a cleaning solution containing a solvent, an organic acid, and an additive that functions as a chelating agent.

[0011] One of the processes used in the process of forming a coating film pattern on a semiconductor wafer substrate is edge bead removal (EBR), which involves spin-coating a coating film-forming composition onto the substrate surface and then removing an unnecessary ring-shaped film from the periphery of the coating film. In this EBR process, a solvent for the coating film is locally ejected from a solvent nozzle onto the periphery of the spin-coated wafer. When removing the film from the periphery of the coating film in EBR, it is necessary to prevent the occurrence of a hump at the edge of the coating film near the boundary with the removal area in order to ensure a circuit pattern formation area and improve the yield of semiconductor devices (Patent Document 6). When forming a metal-containing film using a metal-containing film-forming composition, consideration must be given not only to cleanability, such as removal of the metal-containing film from the periphery of the substrate, but also to the prevention of a hump.

[0012] On the other hand, when considering practicality, when a multi-layer resist process is performed in a single device, wastewater from multiple processes is often discharged through the same pipes, so the cleaning solution must have wastewater stability to prevent unintended events such as metal deposition in the pipes due to interference with other wastewater. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-205685 [Patent Document 2] Patent No. 6714493 [Patent Document 3] Patent No. 6342998 [Patent Document 4] Patent No. 7065076 [Patent Document 5] Patent No. 7274920 [Patent Document 6] Patent No. 6879021 Summary of the Invention [Problem to be solved by the invention]

[0014] The present invention has been made in view of the above circumstances, and aims to provide a cleaning solution that has excellent cleaning properties, such as for removing a metal-containing film from the peripheral edge of a substrate when a metal-containing film-forming composition is applied to the substrate, hump suppression properties, and drainage stability, a method for cleaning a substrate using the same, and a method for forming a metal-containing film using the same cleaning method. [Means for solving the problem]

[0015] In order to solve the above problems, the present invention provides: A cleaning solution for a metal-containing film-forming composition, (A) a solvent; and (B) a cleaning solution containing an organic acid. The cleaning liquid is provided in which the (A) solvent contains at least one first solvent (A-1) having a normal boiling point of less than 160°C and at least one second solvent (A-2) having a normal boiling point of 160°C or higher but lower than 500°C.

[0016] Such a cleaning liquid can provide a cleaning liquid that is excellent in cleaning properties such as removal of a metal-containing film from the peripheral edge of a substrate, hump suppression properties, and drainage stability.

[0017] The second solvent (A-2) is preferably a chain ester, a chain ether, or a combination thereof.

[0018] By using such a solvent, cleaning properties such as removal of a metal-containing film from the peripheral edge of the substrate and hump suppression properties can be improved.

[0019] In this case, the esters are preferably carboxylic acid esters.

[0020] By using such a solvent, cleaning properties such as removal of a metal-containing film from the peripheral edge of the substrate and hump suppression properties can be improved.

[0021] Alternatively, in this case, the ethers are preferably (poly)alkylene glycol dibenzyl ethers or (poly)phenyl ethers.

[0022] By using such a solvent, cleaning properties such as removal of a metal-containing film from the peripheral edge of the substrate and hump suppression properties can be improved.

[0023] The second solvent (A-2) preferably has a surface tension of 29.0 mN / m or more.

[0024] By using such a solvent, it is possible to further improve the hump suppression property.

[0025] In addition, it is preferable that the content of the first solvent (A-1) in the solvent (A) is 30% by mass or more and 98% by mass or less, and the content of the second solvent (A-2) is 2% by mass or more and 70% by mass or less.

[0026] By using such a solvent, it is possible to further improve the metal removal property and the hump suppression property.

[0027] The (B) organic acid is preferably a carboxylic acid.

[0028] When the cleaning liquid contains a carboxylic acid as an organic acid, the metal removal properties can be further improved.

[0029] The content of the (B) organic acid is preferably 1 to 70% by mass relative to the total mass of the cleaning liquid.

[0030] By setting the content of the organic acid in the cleaning solution within the above range, it is possible to further improve the metal removal performance, the stability over time of the cleaning solution, and the drainage stability.

[0031] It is also preferable that the cleaning liquid further contains (C) a compound having a β-diketone as a chelating agent.

[0032] When the cleaning liquid further contains the chelating agent (C) as described above, the metal removal properties can be further improved.

[0033] The content of the (C) chelating agent is preferably 0.1 to 10% by mass relative to the total mass of the cleaning liquid.

[0034] By setting the content of the chelating agent (C) contained in the cleaning solution within the above range, it is possible to further improve the metal removal performance, the stability over time of the cleaning solution, and the drainage stability.

[0035] The present invention also provides a method for cleaning a substrate, the method comprising the step of cleaning a substrate, to which a metal-containing film-forming composition has been directly or indirectly applied, from the peripheral portion of the substrate with the cleaning solution.

[0036] Such a method for cleaning a substrate makes it possible to reduce metal residues on a substrate that are generated when a metal-containing film-forming composition is applied.

[0037] The present invention also provides a method for forming a metal-containing film, comprising the steps of applying a metal-containing film-forming composition directly or indirectly to a substrate and cleaning the metal-containing film-forming composition from the peripheral portion of the substrate with the cleaning solution, wherein the metal-containing film-forming composition contains a metal compound and a solvent.

[0038] Such a method for forming a metal-containing film can reduce metal residues on a substrate that are generated when the metal-containing film-forming composition is applied, and therefore can be suitably used in a process for forming a photoresist film or a resist underlayer film using the metal-containing film-forming composition. [Effects of the Invention]

[0039] As described above, the cleaning solution of the present invention is a cleaning solution containing (A) a solvent and (B) an organic acid, characterized in that the (A) solvent contains at least one first solvent (A-1) having a standard boiling point below 160°C and at least one second solvent (A-2) having a standard boiling point of 160°C or higher but lower than 500°C. This reduces drying of the cleaning solution when removing a metal-containing film-forming composition from the peripheral edge of a substrate, thereby improving the efficiency of metal removal by the organic acid. Furthermore, the high surface tension of the cleaning solution can suppress the occurrence of humps. Substrate cleaning methods and metal-containing film formation methods using this cleaning solution use a cleaning solution that has excellent metal cleaning properties, hump suppression, and drainage stability, allowing for the efficient formation of desired metal-containing films. These cleaning solutions are suitable for use in the manufacture of semiconductor devices, where further miniaturization is expected to continue. [Brief explanation of the drawings]

[0040] [Figure 1] FIG. 1 is a flow diagram of an example of a process for forming a metal-containing film on a substrate and removing the film from the outer peripheral edge using the cleaning solution of the present invention. [Figure 2] 1 is a flow diagram of an example of forming a metal-containing film on a substrate and removing the metal-containing film with the cleaning solution of the present invention. [Figure 3] 1 is a flow diagram of an example of forming a pattern for forming a metal-containing resist underlayer film in the present invention. [Figure 4] FIG. 1 is an explanatory diagram of a method for evaluating hump height in an example. DETAILED DESCRIPTION OF THE INVENTION

[0041] In the manufacturing process of semiconductor devices, one of the processes performed in the process of forming a pattern for forming a metal-containing film is an edge bead removal (EBR) process in which a solvent is supplied to a substrate on which a metal-containing film has been formed, and unnecessary film is removed in a ring shape from the periphery of the coated film. In this EBR process, a cleaning solution is locally ejected from a solvent nozzle onto the periphery of the rotating substrate.

[0042] In the EBR treatment of a metal-containing film, there has been a demand for a cleaning solution that has excellent metal cleaning properties, such as removal of a metal-containing film from the peripheral edge of a substrate when a metal-containing film-forming composition is applied to the substrate, and excellent stability when mixed with other waste liquids, a method for cleaning a semiconductor substrate using the same, and a method for forming a resist underlayer film using the same cleaning method.

[0043] Conventionally, cleaning solutions containing organic solvents and carboxylic acids have been used, but there is room for improvement in metal removal, hump suppression, and drainage stability.

[0044] The present inventors have found that the above-mentioned problems can be overcome by a cleaning liquid for a metal-containing film-forming composition, the cleaning liquid comprising (A) a solvent and (B) an organic acid, wherein the (A) solvent comprises at least one first solvent (A-1) having a standard boiling point of less than 160°C and at least one second solvent (A-2) having a standard boiling point of 160°C or higher but lower than 500°C, and have completed the present invention.

[0045] That is, the present invention provides a cleaning liquid for a metal-containing film-forming composition, the cleaning liquid comprising (A) a solvent and (B) an organic acid, wherein the (A) solvent comprises at least one first solvent (A-1) having a standard boiling point of less than 160°C and at least one second solvent (A-2) having a standard boiling point of 160°C or higher but less than 500°C.

[0046] The present invention will be described in detail below, but the present invention is not limited thereto.

[0047] <Cleaning solution> The cleaning solution of the present invention is a cleaning solution containing (A) a solvent and (B) an organic acid, wherein the solvent (A) contains at least one first solvent (A-1) having a normal boiling point of less than 160° C. and at least one second solvent (A-2) having a normal boiling point of 160° C. or higher but lower than 500° C. The cleaning solution of the present invention is used to clean a substrate coated with a metal-containing film-forming composition.

[0048] ((A) Solvent) The solvent (A) contains a first solvent (A-1) and a second solvent (A-2). The solvent (A) may contain other solvent components in addition to the first solvent (A-1) and the second solvent (A-2). Each of the above solvent components may be used alone or in combination of two or more.

[0049] The cleaning liquid contains (A) a solvent in addition to (B) an organic acid described below, and this (A) solvent contains a first solvent (A-1) having a standard boiling point of less than 160°C and a second solvent (A-2) having a standard boiling point of 160°C or more and less than 500°C. As a result, when the metal-containing film-forming composition is applied to a substrate, the cleaning liquid has excellent metal cleaning properties, such as removal of a metal-containing film from the peripheral edge of the substrate, hump suppression properties, and stability when mixed with other waste liquids.

[0050] The reason why the cleaning liquid having the above-described configuration exhibits the above-described effects is not entirely clear, but can be presumed as follows, for example.

[0051] In the present invention, when removing a metal-containing film, the substrate coated with the metal-containing film is rotated, and a cleaning solution is locally ejected from a solvent nozzle onto the peripheral edge of the coating film, thereby removing the coating film from the peripheral edge. Specifically, by using a mixture of a low-boiling first solvent (A-1) and a high-boiling second solvent (A-2) as the (A) solvent, the drying of the cleaning solution is reduced, allowing the organic acid to act effectively on the metal-containing film at the peripheral edge, improving metal removability. Furthermore, when EBR processing is performed, the coating film is softened and dissolved by the cleaning solution in the area where the cleaning solution is supplied, forming a mixed layer of the coating film and the cleaning solution. When the surface tension of the cleaning solution is low, the cleaning solution easily spreads on the substrate, making it easier for the mixed layer to penetrate into the coating film. This is thought to result in the mixed layer being pushed up near the boundary with the edge of the coating film, causing a bump-like protrusion. It is believed that the cleaning solution of the present invention contains the second solvent (A-2), which increases the surface tension of the cleaning solution and makes it more difficult for the cleaning solution to penetrate to the edge side of the coating film, thereby suppressing the occurrence of humps.

[0052] Each solvent component will be described in detail below.

[0053] [First solvent (A-1)] The first solvent (A-1) component is a solvent having a normal boiling point of less than 160°C.

[0054] The upper limit of the standard boiling point of the first solvent (A-1) component is preferably 158° C., more preferably 156° C. The lower limit of the standard boiling point is preferably 100° C., more preferably 120° C. By setting the standard boiling point of the first solvent (A-1) component within the above range, the stability over time and the drainage stability of the cleaning liquid can be improved.

[0055] Examples of the first solvent (A-1) component include alcohols, esters, ethers, and ketones.

[0056] Examples of the alcohols include monoalcohols such as methanol (boiling point: 65°C), ethanol (boiling point: 78°C), n-propanol (boiling point: 97°C), iso-propanol (boiling point: 82°C), n-butanol (boiling point: 117°C), iso-butanol (boiling point: 108°C), sec-butanol (boiling point: 99°C), tert-butanol (boiling point: 82°C), n-pentanol (boiling point: 138°C), iso-pentanol (boiling point: 132°C), 2-methylbutanol (boiling point: 136°C), sec-pentanol (boiling point: 118°C), and tert-pentanol (boiling point: 102°C). ), 2-methylpentanol (boiling point: 148°C), 2-ethylbutanol (boiling point: 146°C), 3-methoxybutanol (boiling point: 157°C), n-hexanol (boiling point: 157°C), etc., and alkylene glycol monoalkyl ethers include ethylene glycol monomethyl ether (boiling point: 125°C), ethylene glycol monoethyl ether (boiling point: 135°C), propylene glycol monomethyl ether (boiling point: 121°C), propylene glycol monoethyl ether (boiling point: 133°C), propylene glycol monopropyl ether (boiling point: 149.8°C), etc.

[0057] Examples of the esters include carboxylic acid esters, etc. Examples of the carboxylic acid esters include acetates such as butyl acetate (boiling point: 151°C), propionates such as isoamyl propionate (boiling point: 156°C), and lactates such as ethyl lactate (boiling point: 151°C).

[0058] Examples of the ethers include alkylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate (boiling point: 145° C.) and propylene glycol monomethyl ether acetate (boiling point: 146° C.).

[0059] The ketones include, for example, 2-heptanone (boiling point: 151° C.).

[0060] Among these, as the first solvent (A-1) component, from the viewpoint of compatibility with the (B) organic acid, esters and / or ethers are preferred, chain esters and / or chain ethers are more preferred, carboxylic acid esters, alkylene glycol monoalkyl ethers and / or alkylene glycol monoalkyl ether acetates are more preferred, lactic acid esters, alkylene glycol monoalkyl ethers and / or alkylene glycol monoalkyl ether acetates are even more preferred, and propylene glycol methyl ethyl acetate (PGMEA) is particularly preferred.

[0061] The lower limit of the content of the first solvent (A-1) component in the solvent (A) is preferably 30 mass%, more preferably 35 mass%, and even more preferably 50 mass%. The upper limit of the content is preferably 98 mass%, more preferably 97 mass%, and even more preferably 96 mass%. By keeping the content of the first solvent (A-1) within the above range, the stability over time and the drainage stability of the cleaning liquid can be improved.

[0062] [Second solvent (A-2)] The second solvent (A-2) component is a solvent having a normal boiling point of 160°C or higher and lower than 500°C.

[0063] The lower limit of the standard boiling point of the second solvent (A-2) component is preferably 170° C., more preferably 180° C., and even more preferably 190° C. The upper limit of the standard boiling point is less than 500° C., more preferably 450° C., even more preferably 400° C., and particularly preferably 350° C. By setting the standard boiling point of the second solvent (A-2) component within the above range, the metal removal ability, hump suppression ability, stability over time, and drainage stability of the cleaning liquid can be improved.

[0064] Examples of the second solvent (A-2) component include esters, alcohols, ethers, carbonates, ketones, and amides.

[0065] Examples of the esters include carboxylic acid esters such as acetate esters such as 2-ethylbutyl acetate (boiling point: 160°C), 2-ethylhexyl acetate (boiling point: 199°C), benzyl acetate (boiling point: 212°C), cyclohexyl acetate (boiling point: 172°C), methylcyclohexyl acetate (boiling point: 201°C), n-nonyl acetate (boiling point: 208°C), and 1,6-diacetoxyhexane (boiling point: 260°C); acetoacetates such as methyl acetoacetate (boiling point: 169°C) and ethyl acetoacetate (boiling point: 181°C); and isoamyl propionate (boiling point: 182°C). Examples of suitable esters include propionic acid esters such as diethyl oxalate (boiling point: 185°C) and di-n-butyl oxalate (boiling point: 239°C), lactic acid esters such as n-butyl lactate (boiling point: 185°C), malonic acid esters such as diethyl malonate (boiling point: 199°C), phthalic acid esters such as dimethyl phthalate (boiling point: 283°C), and lactones such as β-propiolactone (boiling point: 162°C), γ-butyrolactone (boiling point: 204°C), γ-valerolactone (boiling point: 207°C), and γ-undecalactone (boiling point: 286°C).

[0066] Examples of the alcohols include monoalcohols such as n-octanol (boiling point: 194°C), sec-octanol (boiling point: 174°C), n-nonyl alcohol (boiling point: 215°C), n-decanol (boiling point: 228°C), phenol (boiling point: 182°C), cyclohexanol (boiling point: 161°C), and benzyl alcohol (boiling point: 205°C); and examples of the polyhydric alcohols include ethylene glycol (boiling point: 197°C), 1,2-propylene glycol (boiling point: 188°C), 1,3-butylene glycol (boiling point: 208°C), 2,4-pentanediol (boiling point: 201°C), 2-methyl-2,4-pentanediol (boiling point: 196°C), 2,5-hexanediol (boiling point: 216°C), triethylene glycol (boiling point: 165°C), dipropylene glycol (boiling point: 230°C), etc., are polyhydric alcohol partial ethers, such as ethylene glycol monobutyl ether (boiling point: 171°C), ethylene glycol monophenyl ether (boiling point: 244°C), diethylene glycol monomethyl ether (boiling point: 194°C), diethylene glycol monoethyl ether (boiling point: 202°C), triethylene glycol monomethyl ether (boiling point: 249°C), diethylene glycol monoisopropyl ether (boiling point: 207°C), diethylene glycol monobutyl ether (boiling point: 231°C), triethylene glycol monobutyl ether (boiling point: 271°C), ethylene glycol monoisobutyl ether (boiling point: 161°C), diethylene glycol monoisobutyl ether (boiling point: 220°C), and ethylene glycol monohexyl ether (boiling point: 208°C). ), diethylene glycol monohexyl ether (boiling point: 259 ° C), ethylene glycol mono 2-ethylhexyl ether (boiling point: 229 ° C), diethylene glycol mono 2-ethylhexyl ether (boiling point: 272 ° C), ethylene glycol monoallyl ether (boiling point: 161 ° C), diethylene glycol monophenyl ether (boiling point: 283 ° C), ethylene glycol monobenzyl ether (boiling point: 256 ° C), diethylene glycol monobenzyl ether (boiling point: 302 ° C), dipropylene glycol monomethyl ether (boiling point: 187 ° C), tripropylene glycol monomethyl ether (boiling point: 242 ° C), dipropylene glycol monopropyl ether (boiling point: 212 ° C), propylene glycol monobutyl ether (boiling point: 170 ° C), dipropylene glycol monobutyl ether (boiling point: 231 ° C), propylene glycol monophenyl ether (boiling point: 243 ° C), and the like.

[0067] Examples of the ethers include dialkylene glycol monoalkyl ether acetates such as dipropylene glycol monomethyl ether acetate (standard boiling point: 213°C), diethylene glycol monoethyl ether acetate (boiling point: 217°C), and diethylene glycol monobutyl ether acetate (standard boiling point: 247°C); alkylene glycol monoalkyl ether acetates such as butylene glycol monomethyl ether acetate (boiling point: 172°C) and ethylene glycol monobutyl ether acetate (boiling point: 188°C); and dialkylene glycol dialkyl ethers such as diethylene glycol dimethyl ether (boiling point: 162°C) and diethylene glycol methyl ethyl ether (boiling point: 176°C). Examples of the alkyl ethers include triethylene glycol dimethyl ether (boiling point: 216°C), tetraethylene glycol dimethyl ether (boiling point: 275°C), and other alkyl ethers. Examples of the alkyl ethers include 1,8-cineole (boiling point: 176°C), diisopentyl ether (boiling point: 171°C), ethyl benzyl ether (boiling point: 189°C), diphenyl ether (boiling point: 259°C), dibenzyl ether (boiling point: 297°C), hexyl ether (boiling point: 226°C), and the like.

[0068] Examples of the carbonates include ethylene carbonate (boiling point: 244° C.) and propylene carbonate (boiling point: 242° C.).

[0069] Examples of the ketones include ethyl amyl ketone (boiling point: 167°C), dibutyl ketone (boiling point: 186°C), and diamyl ketone (boiling point: 228°C).

[0070] Examples of the amides include N-methylpyrrolidone (boiling point: 204°C), N,N-dimethylacetamide (boiling point: 165°C), formamide (boiling point: 210°C), N-ethylacetamide (boiling point: 206°C), and N-methylacetamide (boiling point: 206°C).

[0071] Other examples of second solvent (A-2) components include furfural (boiling point: 162°C), dimethyl sulfoxide (boiling point: 189°C), sulfolane (boiling point: 287°C), glycerin (boiling point: 290°C), succinonitrile (boiling point: 265°C), and nitrobenzene (boiling point: 211°C).

[0072] Of these, the second solvent (A-2) component is preferably an ester, an alcohol, an ether, and / or a carbonate, and more preferably a chain ester, a chain ether, or a combination thereof.

[0073] The esters are preferably carboxylic acid esters, and the ethers are preferably (poly)alkylene glycol dibenzyl ethers and (poly)phenyl ethers.

[0074] More preferred structures include the following: (i) (Poly)ethylene glycol dibenzoate (ii) (Poly)ethylene glycol dibenzyl ether (iii) (Poly)propylene glycol dibenzyl ether (iv) (Poly)butylene glycol dibenzyl ether (v) Dibenzyl linear aliphatic dicarboxylate (vi) (Poly)phenyl ethers

[0075] [ka] (In the formula, n is a repeating unit, for example, n=1 to 100.)

[0076] The surface tension of the second solvent (A-2) is preferably 29.0 mN / m or more, more preferably 30.0 mN / m or more, and even more preferably 31.0 mN / m or more. There is no particular upper limit to the surface tension of the second solvent (A-2), but it can be, for example, 50.0 mN / m or less. By using a solvent having such a surface tension as the second solvent, the hump suppression ability of the cleaning liquid can be further improved.

[0077] Examples of the second solvent (A-2) component having a normal boiling point of 160° C. or higher and lower than 500° C. and a surface tension value within the above range include the following.

[0078] Propyl benzoate (boiling point 230°C, surface tension 34.8mN / m), butyl benzoate (boiling point 250°C, surface tension 34.2mN / m), benzyl benzoate (boiling point 324°C, surface tension 43.4mN / m), diethylene glycol dibenzoate (boiling point 236°C, surface tension 45.5mN / m), bis(2-ethylhexyl) sebacate (boiling point 377°C, surface tension 31 0.9mN / m), 1,6-diacetoxyhexane (boiling point 260°C, surface tension 34.8mN / m), γ-butyrolactone (boiling point 204°C, surface tension 44.8mN / m), diethylene glycol monobenzyl ether (boiling point 302°C, surface tension 42.9mN / m), tripropylene glycol monomethyl ether (boiling point 242°C, surface tension 30.5mN / m). The surface tensions are shown as the results of measuring the surface tension of the solvents using a Dunouy-type surface tension tester, Model D (manufactured by Ito Seisakusho).

[0079] The lower limit of the content of the second solvent (A-2) component in the solvent (A) is preferably 2% by mass, more preferably 3% by mass, even more preferably 4% by mass, particularly preferably 4% by mass, and even more particularly preferably 8% by mass. The upper limit of the content is preferably 70% by mass, more preferably 65% ​​by mass, even more preferably 50% by mass, particularly preferably 30% by mass, and even more particularly preferably 20% by mass. By keeping the content of the second solvent (A-2) within the above range, the metal removal ability and hump suppression ability, as well as the stability over time and drainage stability of the cleaning liquid can be highly improved.

[0080] In the cleaning liquid of the present invention, it is particularly preferred that the content of the first solvent (A-1) in the solvent (A) is 30% by mass or more and 98% by mass or less, and the content of the second solvent (A-2) is 2% by mass or more and 70% by mass or less.

[0081] ((B) Organic acid) The cleaning solution of the present invention preferably contains an organic acid (B). By adding an organic acid (B) to the cleaning solution, the removability of the metal-containing film-forming material formed on the substrate is improved.

[0082] Examples of the (B) organic acid include carboxylic acids, sulfonic acids, sulfinic acids, organic phosphinic acids, organic phosphonic acids, phenols, enols, thiols, acid imides, oximes, and sulfonamides.

[0083] The (B) organic acid is preferably a carboxylic acid. More specifically, for example, carboxylic acids consisting of an aliphatic saturated hydrocarbon group and / or an aromatic hydrocarbon group and a carboxy group, such as formic acid, acetic acid, propionic acid, butanoic acid (butyric acid), isobutanoic acid (isobutyric acid), pentanoic acid, hexanoic acid, 2-ethylhexanoic acid, cyclohexanecarboxylic acid, cyclohexylacetic acid, 1-adamantanecarboxylic acid, benzoic acid, and phenylacetic acid; fluorine atom-containing monocarboxylic acids, such as difluoroacetic acid, trifluoroacetic acid, pentafluoropropanoic acid, heptafluorobutanoic acid, fluorophenylacetic acid, and difluorobenzoic acid; monocarboxylic acids containing a heteroatom-containing group other than a fluorine atom in a moiety other than the carboxy group, such as 10-hydroxydecanoic acid, 5-oxohexanoic acid, 3-methoxycyclohexanecarboxylic acid, camphorcarboxylic acid, dinitrobenzoic acid, nitrophenylacetic acid, lactic acid, glycolic acid, glyceric acid, salicylic acid, anisic acid, gallic acid, and furancarboxylic acid; acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, 3-butenoic acid, and angelic acid. unsaturated monocarboxylic acids such as tiglic acid, 4-pentenoic acid, cinnamic acid, sorbic acid, propiolic acid, and 2-butynoic acid; polycarboxylic acids consisting of a single bond, an aliphatic saturated hydrocarbon group and / or an aromatic hydrocarbon group, and a plurality of carboxy groups, such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, dodecanedicarboxylic acid, propanetricarboxylic acid, butanetetracarboxylic acid, cyclohexanehexacarboxylic acid, 1,4-naphthalenedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, and 1,2,3,4-cyclobutanetetracarboxylic acid; partially esterified products of the above polycarboxylic acids; fluorine atom-containing polycarboxylic acids such as difluoromalonic acid, tetrafluorophthalic acid, and hexafluoroglutaric acid; polycarboxylic acids containing heteroatoms other than fluorine atoms in moieties other than the carboxy group, such as tartaric acid, citric acid, malic acid, tartronic acid, diglycolic acid, and iminodiacetic acid; and unsaturated polycarboxylic acids such as maleic acid, fumaric acid, and aconitic acid.

[0084] From the viewpoint of cleaning properties and wastewater stability, it is more preferable that the (B) organic acid is at least one selected from the group consisting of formic acid, acetic acid, citric acid, oxalic acid, 2-ethylhexanoic acid, dodecanoic acid, ascorbic acid, tartaric acid, glucuronic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, and 3-butenoic acid.

[0085] The lower limit of the content of (B) organic acid relative to all components contained in the cleaning solution is preferably 1 mass%, more preferably 1.5 mass%, even more preferably 2 mass%, and particularly preferably 3 mass%. The upper limit of the content is preferably 70 mass%, more preferably 60 mass%, even more preferably 55 mass%, and particularly preferably 50 mass%. By keeping the content of the organic acid within the above range, it is possible to further improve cleaning properties and drainage stability.

[0086] In the cleaning liquid of the present invention, the content of the (B) organic acid is preferably 1 to 70% by mass relative to the total mass of the cleaning liquid.

[0087] ((C) Chelating agent) The cleaning solution of the present invention may contain (C) a chelating agent to further improve metal removal. From the viewpoint of cleaning performance, the chelating agent is preferably a compound having a β-diketone structure. Specific examples of the chelating agent include 2,4-pentanedione (acetylacetone), 3-methyl-2,4-pentanedione, 3-ethyl-2,4-pentanedione, acetoacetic acid ester, allyl acetoacetate, α-alkyl-substituted acetoacetic acid ester, β-ketopentanoic acid ester, benzoyl acetate, and 1,3-acetonedicarboxylic acid ester.

[0088] In the cleaning liquid of the present invention, the content of the chelating agent (C) is preferably 0.1 to 10% by mass relative to the total mass of the cleaning liquid.

[0089] (Other ingredients) The cleaning solution of the present invention may contain other components in addition to the above components, such as inorganic hydrofluoric acid, a tetraalkylammonium compound, and a surfactant.

[0090] Examples of inorganic hydrofluoric acid include hexafluorosilicic acid, hexafluorophosphoric acid, and fluoroboric acid.

[0091] Examples of the tetraalkylammonium compound include tetramethylammonium fluoride, tetrabutylammonium fluoride, and tetrabutylammonium fluorosilicate.

[0092] As the surfactant, for example, those described in paragraphs

[0142] to

[0147] of JP-A-2009-269953 can be used.

[0093] Any one of the additives may be used alone, or two or more of them may be used in combination. In the cleaning liquid of the present invention, the content of the additives is preferably 0 to 10% by mass relative to the total mass of the cleaning liquid.

[0094] <How to prepare cleaning solution> The cleaning solution of the present invention can be prepared by mixing (A) a solvent, (B) an organic acid, and, if necessary, (C) a chelating agent and / or optional components in a predetermined ratio, and preferably filtering the resulting mixture through a membrane filter or the like having a pore size of 0.5 μm or less.

[0095] <Substrate cleaning method and metal-containing film forming method> The cleaning solution of the present invention is used to remove a metal-containing film-forming composition from the peripheral edge of a substrate when the metal-containing film-forming composition is applied to the substrate.

[0096] Therefore, the present invention provides a method for cleaning a substrate, which includes a step of cleaning a substrate to which a metal-containing film-forming composition has been directly or indirectly applied, from the peripheral portion of the substrate with the cleaning solution of the present invention.

[0097] Furthermore, the present invention provides a method for forming a metal-containing film, which includes a step of applying a metal-containing film-forming composition directly or indirectly to a substrate (coating step), and a step of cleaning the metal-containing film-forming composition from the peripheral portion of the substrate with the cleaning solution of the present invention (cleaning step), wherein the metal-containing film-forming composition contains a metal compound and a solvent.

[0098] When the metal-containing film-forming composition is a material for a resist underlayer film, it is preferable to further perform, after the cleaning step, a resist pattern-forming step of directly or indirectly forming a photoresist film on the metal-containing film formed in the coating step, exposing the photoresist film, forming a photoresist pattern by development, and directly or indirectly transferring the resist pattern to the metal-containing film by etching using the resist pattern as a mask. Hereinafter, these steps are collectively referred to as a "method for producing a semiconductor substrate."

[0099] When the metal-containing film-forming composition is a material for a photoresist film, the method preferably includes, after the cleaning step, a step of exposing the photoresist film to light, a step of forming a photoresist pattern by development, and a step of transferring the resist pattern directly or indirectly to a substrate by etching using the resist pattern as a mask.

[0100] The peripheral edge of the substrate refers to, for example, a portion of the outer periphery of the substrate whose length from the outer periphery edge to the center of the substrate is within 3.0 cm, and the length from the outer periphery edge to the center of the substrate can be 2.0 cm, 1.0 cm, 0.5 cm, or 0.2 cm.

[0101] When the metal-containing film-forming composition is a material for a resist underlayer film, the method for producing a semiconductor substrate may further include, as necessary, a step of forming an organic resist intermediate film directly or indirectly on the substrate having the metal-containing film formed in the coating step (organic resist intermediate film formation step) prior to the resist pattern formation step.

[0102] When the metal-containing film-forming composition is a material for a resist underlayer film, the method for producing a semiconductor substrate may, as necessary, further include, prior to the resist pattern formation step, a step of forming a silicon-containing film directly or indirectly on the substrate having the metal-containing film formed in the coating step (silicon-containing film formation step).

[0103] Hereinafter, the metal-containing film-forming composition and cleaning solution used in the method for producing a semiconductor substrate, as well as each step in the case where the method includes the optional steps of forming an organic resist intermediate film and forming a silicon-containing film, will be described.

[0104] <Metal-containing film forming composition> The metal-containing film-forming composition to which the cleaning solution of the present invention can be applied is not particularly limited as long as it contains (M) a metal compound and (B) a solvent. The composition may contain other optional components. The metal-containing film-forming composition is preferably a material that can be used as a photoresist film or a resist underlayer film.

[0105] The (M) metal compound is preferably a compound containing a metal atom and an oxygen atom. Examples of the metal atom constituting the (M) metal compound include metal atoms of Groups 3 to 16 of the periodic table (excluding silicon atoms). The (M) metal compound may contain one or more types of metal atoms.

[0106] Examples of metal atoms in Group 3 include scandium, yttrium, lanthanum, and cerium.

[0107] Examples of metal atoms in Group 4 include titanium, zirconium, and hafnium.

[0108] Examples of metal atoms in Group 5 include vanadium, niobium, and tantalum.

[0109] Examples of metal atoms in Group 6 include chromium, molybdenum, and tungsten.

[0110] Examples of metal atoms in Group 7 include manganese and rhenium.

[0111] Examples of metal atoms in Group 8 include iron, ruthenium, and osmium.

[0112] Examples of metal atoms in Group 9 include cobalt, rhodium, and iridium.

[0113] Examples of metal atoms in Group 10 include nickel, palladium, and platinum.

[0114] Examples of metal atoms in Group 11 include copper, silver, and gold.

[0115] Examples of metal atoms in Group 12 include zinc, cadmium, and mercury.

[0116] Examples of metal atoms in Group 13 include aluminum, gallium, and indium.

[0117] Examples of metal atoms in Group 14 include germanium, tin, and lead.

[0118] Examples of metal atoms in Group 15 include antimony and bismuth.

[0119] Examples of metal atoms in Group 16 include tellurium.

[0120] The metal atoms constituting the (M) metal compound are preferably metal atoms of Groups 3 to 16, more preferably metal atoms of Groups 4 to 14, still more preferably metal atoms of Groups 4, 5 and 14, and particularly preferably metal atoms of Group 4. Specifically, titanium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, molybdenum, indium, tin, hafnium, tantalum, tungsten, and bismuth, or a combination thereof, are preferred.

[0121] The components other than the metal atom that constitute the (M) metal compound preferably include one or more ligands derived from a hydrolyzable group, or an organic acid (hereinafter also referred to as "(a) organic acid"), a hydroxy acid ester, a β-diketone, a β-ketoester, an α,α-dicarboxylic acid ester, an amine, an amide, an olefin, a hydrocarbon having a π bond, and a compound containing a diphosphine. Here, "organic acid" refers to an organic compound that exhibits acidity, and "organic compound" refers to a compound having at least one carbon atom. The form in which the (a) organic acid is contained also includes an organic acid anion obtained by removing a hydrogen ion from the (a) organic acid.

[0122] Examples of the hydrolyzable group include a halogen atom, an alkoxy group, and an acyloxy group.

[0123] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0124] The alkoxy group is preferably an alkoxy group having 1 to 10 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, a butoxy group, and an octyl group.

[0125] Examples of the acyloxy group include an acetoxy group, an ethyryloxy group, a propionyloxy group, a butyryloxy group, a t-butyryloxy group, a t-amylyloxy group, an n-hexanecarbonyloxy group, and an n-octanecarbonyloxy group.

[0126] The hydrolyzable group is preferably an alkoxy group or an acyloxy group, and more preferably an n-propoxy group, an i-propoxy group, a butoxy group, or an octyl group.

[0127] (a) Examples of organic acids include carboxylic acids, sulfonic acids, sulfinic acids, organic phosphinic acids, organic phosphonic acids, phenols, enols, thiols, acid imides, oximes, and sulfonamides.

[0128] Examples of the carboxylic acid include monocarboxylic acids such as formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, 2-ethylhexanoic acid, oleic acid, acrylic acid, methacrylic acid, trans-2,3-dimethylacrylic acid, stearic acid, linoleic acid, linolenic acid, arachidonic acid, salicylic acid, benzoic acid, p-aminobenzoic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, pentafluoropropionic acid, gallic acid, and shikimic acid; dicarboxylic acids such as oxalic acid, malonic acid, maleic acid, methylmalonic acid, fumaric acid, adipic acid, sebacic acid, phthalic acid, and tartaric acid; and carboxylic acids having three or more carboxy groups, such as citric acid.

[0129] Examples of the sulfonic acid include benzenesulfonic acid and p-toluenesulfonic acid.

[0130] Examples of the sulfinic acid include benzenesulfinic acid and p-toluenesulfinic acid.

[0131] Examples of the organic phosphinic acid include diethylphosphinic acid, methylphenylphosphinic acid, and diphenylphosphinic acid.

[0132] Examples of the organic phosphonic acid include methylphosphonic acid, ethylphosphonic acid, t-butylphosphonic acid, cyclohexylphosphonic acid, and phenylphosphonic acid.

[0133] Examples of the phenols include monohydric phenols such as phenol, cresol, 2,6-xylenol, and naphthol; dihydric phenols such as catechol, resorcinol, hydroquinone, and 1,2-naphthalenediol; and trihydric or higher phenols such as pyrogallol and 2,3,6-naphthalenetriol.

[0134] Examples of the enol include 2-hydroxy-3-methyl-2-butene and 3-hydroxy-4-methyl-3-hexene.

[0135] Examples of the thiol include mercaptoethanol and mercaptopropanol.

[0136] Examples of the acid imide include carboxylic acid imides such as maleimide and succinimide, and sulfonic acid imides such as di(trifluoromethanesulfonic acid)imide and di(pentafluoroethanesulfonic acid)imide.

[0137] Examples of the oxime include aldoximes such as benzaldoxime and salicylaldoxime, and ketoximes such as diethylketoxime, methylethylketoxime and cyclohexanoneoxime.

[0138] Examples of the sulfonamide include methylsulfonamide, ethylsulfonamide, benzenesulfonamide, and toluenesulfonamide.

[0139] (a) The organic acid is preferably a carboxylic acid having 1 to 10 carbon atoms.

[0140] Examples of the hydroxy acid ester include glycolic acid ester, lactic acid ester, 2-hydroxycyclohexane-1-carboxylic acid ester, and salicylic acid ester.

[0141] Examples of the β-diketone include 2,4-pentanedione, 3-methyl-2,4-pentanedione, and 3-ethyl-2,4-pentanedione.

[0142] Examples of the β-ketoester include acetoacetic ester, α-alkyl-substituted acetoacetic ester, β-ketopentanoic ester, benzoylacetic ester, and 1,3-acetonedicarboxylic ester.

[0143] Examples of the α,α-dicarboxylic acid ester include malonic acid diester, α-alkyl-substituted malonic acid diester, α-cycloalkyl-substituted malonic acid diester, and α-aryl-substituted malonic acid diester.

[0144] Examples of the amine-containing compound include pyridine, trimethylamine, piperidine, diethanolamine, and triethanolamine.

[0145] Examples of compounds containing amide include compounds containing unsubstituted amide (NH2), methylamide (NHMe), dimethylamide (NMe2), diethylamide (NEt2), dipropylamide (NPr2), and the like.

[0146] Examples of the olefin-containing compound include chain olefins such as ethylene and propylene, and cyclic olefins such as cyclopentene, cyclohexene and norbornene.

[0147] Examples of the hydrocarbon having a π bond include chain dienes such as butadiene and isoprene, cyclic dienes such as cyclopentadiene, methylcyclopentadiene, pentamethylcyclopentadiene, cyclohexadiene and norbornadiene, and aromatic hydrocarbons such as benzene, toluene, xylene, hexamethylbenzene, naphthalene and indene.

[0148] Examples of the diphosphine-containing compound include 1,1-bis(diphenylphosphino)methane, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, and 1,1′-bis(diphenylphosphino)ferrocene.

[0149] Examples of the (M) metal compound include compounds represented by the following formula (M-1): By using such a metal compound (M-1), a stable (M) metal compound can be formed, and dry etching resistance can be improved.

[0150] [ka] (wherein M is any one of titanium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, molybdenum, indium, tin, hafnium, tantalum, tungsten, and bismuth; L is a monodentate or polydentate ligand having 1 to 30 carbon atoms; X is a halogen atom, an alkoxy group, a carboxylate group, an acyloxy group, -NR a R b R is a hydrolyzable group selected from a and R b are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms; a+c=1 to 6, a is an integer of 0 to 4, b is an integer of 0 to 2, and c is an integer of 0 to 6.

[0151] Examples of the hydrolyzable group X in the above formula (M-1) include a halogen atom, an alkoxy group, a carboxylate group, an acyloxy group, and —NR a R b Examples include: R a and R b are preferably each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms.

[0152] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0153] Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, and a t-butoxy group.

[0154] Examples of the carboxylate group include monocarboxylic acids such as formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, 2-ethylhexanoic acid, oleic acid, acrylic acid, methacrylic acid, trans-2,3-dimethylacrylic acid, stearic acid, linoleic acid, linolenic acid, arachidonic acid, salicylic acid, benzoic acid, p-aminobenzoic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, pentafluoropropionic acid, gallic acid, and shikimic acid; dicarboxylic acids such as oxalic acid, malonic acid, maleic acid, methylmalonic acid, fumaric acid, adipic acid, sebacic acid, phthalic acid, and tartaric acid; and ligands derived from carboxylic acids having three or more carboxy groups, such as citric acid.

[0155] Examples of the acyloxy group include an acetoxy group, an ethyryloxy group, a propionyloxy group, a butyryloxy group, a t-butyryloxy group, a t-amylyloxy group, an n-hexanecarbonyloxy group, and an n-octanecarbonyloxy group.

[0156] Above -NR a R b Examples of the amino group include an unsubstituted amino group, a methylamino group, a dimethylamino group, a diethylamino group, and a dipropylamino group.

[0157] The hydrolyzable group X is preferably an alkoxy group, more preferably an i-propoxy group, an n-butoxy group, or a t-butoxy group.

[0158] (monodentate ligand) Examples of the monodentate ligand L include a hydroxo ligand, a carboxy ligand, an amide ligand, an amine ligand, and an olefin ligand.

[0159] Examples of the carboxy ligand include monocarboxylic acids such as formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, 2-ethylhexanoic acid, oleic acid, acrylic acid, methacrylic acid, trans-2,3-dimethylacrylic acid, stearic acid, linoleic acid, linolenic acid, arachidonic acid, salicylic acid, benzoic acid, p-aminobenzoic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, pentafluoropropionic acid, gallic acid, and shikimic acid; dicarboxylic acids such as oxalic acid, malonic acid, maleic acid, methylmalonic acid, fumaric acid, adipic acid, sebacic acid, phthalic acid, and tartaric acid; and ligands derived from carboxylic acids having three or more carboxy groups, such as citric acid.

[0160] Examples of the amide ligand include an unsubstituted amide ligand (NH2), a methylamide ligand (NHMe), a dimethylamide ligand (NMe2), a diethylamide ligand (NEt2), and a dipropylamide ligand (NPr2).

[0161] Examples of the amine ligand include pyridine, trimethylamine ligand, and piperidine ligand.

[0162] Examples of the olefin ligand include chain olefins such as ethylene and propylene, and cyclic olefins such as cyclopentene, cyclohexene and norbornene.

[0163] (polydentate ligand) Examples of the polydentate ligand L include a ligand derived from a hydroxy acid ester, a ligand derived from a β-diketone, a ligand derived from a β-ketoester, a ligand derived from an α,α-dicarboxylic acid ester, a hydrocarbon having a π bond, and a diphosphine.

[0164] Examples of the hydroxy acid ester include glycolic acid ester, lactic acid ester, 2-hydroxycyclohexane-1-carboxylic acid ester, salicylic acid ester, and the like.

[0165] Examples of the β-diketone include acetoacetic ester, α-alkyl-substituted acetoacetic ester, β-ketopentanoic ester, benzoylacetic ester, and 1,3-acetonedicarboxylic ester.

[0166] Examples of the β-ketoester include acetoacetic ester, α-alkyl-substituted acetoacetic ester, β-ketopentanoic ester, benzoylacetic ester, and 1,3-acetonedicarboxylic ester.

[0167] Examples of the α,α-dicarboxylic acid ester include malonic acid diester, α-alkyl-substituted malonic acid diester, α-cycloalkyl-substituted malonic acid diester, and α-aryl-substituted malonic acid diester.

[0168] Examples of the hydrocarbon having a π bond include chain dienes such as butadiene and isoprene, cyclic dienes such as cyclopentadiene, methylcyclopentadiene, pentamethylcyclopentadiene, cyclohexadiene and norbornadiene, and aromatic hydrocarbons such as benzene, toluene, xylene, hexamethylbenzene, naphthalene and indene.

[0169] Examples of the diphosphines include 1,1-bis(diphenylphosphino)methane, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, and 1,1′-bis(diphenylphosphino)ferrocene.

[0170] The monodentate and polydentate ligands may contain a crosslinkable group. The crosslinkable group preferably contains any of a vinyl group, an allyl group, an allyloxy group, an ethynyl group, a propargyl group, a propargyloxy group, an epoxy group, and an oxetanyl group. By using a metal compound having such a ligand, a metal-containing film with excellent thermosetting properties can be formed.

[0171] The (M) metal compound may be, for example, an anion of an oxoacid (phosphate ion, sulfate ion, chromate ion, tungstate ion (WO4 2- ), molybdate ion (MoO4 2- ) or a compound containing an inorganic anion such as a polyacid anion formed by condensation of a plurality of oxo acids, or a mixture thereof.

[0172] The polyacid may be an isopolyacid anion (Mm'On') c- Even if the heteropoly acid anion (X l 'Mm'On') c- In the above ionic formula, M is a polyatom, X is a heteroatom, m' is the composition ratio of polyatoms, n' is the composition ratio of oxygen atoms, and l' is the composition ratio of heteroatoms. c is the valence. Examples of polyatoms M include Mo, W, Ti, and Nb. Examples of heteroatoms X include Si, P, As, S, Fe, and Co. In addition, Na may be used as a part of the polyatoms. + and H + Counter cations such as may be included.

[0173] Among these, anions of inorganic acids containing at least one of tungsten (W) and molybdenum (Mo) are preferred because of their excellent heat resistance.

[0174] Examples of polyacids containing at least one of tungsten (W) and molybdenum (Mo) include isopolyacids containing tungstate ions [W 10 O 32 ] 4- , molybdate ion [MoO 19 ] 2- and heteropolyacid, phosphotungstate ion [PW 12 O 40 ] 3- , [P2W 18 O 62 ] 6- , silicotungstate ion [SiW 12 O 40 ] 4- , phosphomolybdate ion [PMo12 O 40 ] 3- , silicomolybdate ion [SiMo 12 O 40 ] 4- , phosphotungstomolybdate ion [PW 12-x Mo x O 40 ] 3- (x is an integer between 1 and 11), [P2W 18-y Mo y O 62 ] 6- (y is an integer from 1 to 17), silicotungstomolybdate ion [SiW 12-x Mo x O 40 ] 4- (x is an integer of 1 to 11). As the polyacid containing at least one of tungsten (W) and molybdenum (Mo), heteropolyacids are preferred among the above, from the viewpoints of heat resistance and ease of raw material availability, and heteropolyacids containing phosphorus (P) are more preferred.

[0175] Furthermore, phosphotungstomolybdate ions [PW 10 Mo2O 40 ] 3- , [PW 11 Mo1O 40 ] 3- , phosphotungstate ion [PW 12 O 40 ] 3- From the viewpoint of heat resistance, it is more preferable that the material is one of the above.

[0176] The (M) metal compound may be a hydrolyzate of a metal compound containing a hydrolyzable group, a hydrolysis condensation product of a metal compound containing a hydrolyzable group, or a combination thereof. Here, the term "hydrolysis condensation reaction" refers to a reaction in which a hydrolyzable group of a metal compound is hydrolyzed to convert it to -OH, and the two resulting -OH groups undergo dehydration condensation to form -O-.

[0177] Alternatively, it is also possible to use compounds obtained by reacting these compounds with a substance that can become a monodentate ligand or a polydentate ligand through a ligand exchange reaction, and it is also possible to use compounds obtained by reacting a hydrolysis reaction product of a metal-containing compound having a hydrolyzable group or a hydrolysis condensation reaction product of a metal-containing compound having a hydrolyzable group with a substance that can become a monodentate ligand or a polydentate ligand.

[0178] Specific examples of the (M) metal compound include, but are not limited to, the following.

[0179] Examples of titanium-containing compounds include diisopropoxybis(2,4-pentanedionato)titanium(IV), tetra-n-butoxytitanium(IV), tetra-n-propoxytitanium(IV), tetraisopropoxytitanium(IV), tri-n-butoxymonostearatetitanium(IV), tetrakis(2-ethylhexyl) orthotitanate, dihydroxybis(hydrogen lactato)titanium(IV), titanium(IV) butoxide oligomer, aminopropyltrimethoxytitanium(IV), triethoxymono(2,4-pentanedionato)titanium(IV), tri-n-propoxymono(2,4-pentanedionato)titanium(IV), triisopropoxymono(2,4-pentanedionato)titanium, and di-n-butoxybis(2,4-pentanedionato)titanium(IV).

[0180] Examples of chromium-containing compounds include chromium(III) tris(2-ethylhexanoate), chromium(III) tris(2,4-pentanedionato), chromium(III) bis(2,2,6,6-tetramethyl-3,5-heptanedionato), chromium(II) tris(trifluoro-2,4-pentanedionato), chromium(III) pyridine-2-carboxylate, chromium(III) chloride, chromium(II) chloride, and chromium(II) cyclohexanecarboxylate.

[0181] Examples of nickel-containing compounds include nickel(II) acetate, nickel chloride, nickel(II) 2-ethylhexanoate, bis(2,4-pentanedionato)nickel(II) hydrate, bis(hexafluoroacetylacetonato)nickel(II), 2-amino-5-methylbenzenesulfonate nickel(II), nickel trifluoromethanesulfonate, bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II), and nickel(II) propionate.

[0182] Examples of manganese-containing compounds include tris(2,2,6,6-tetramethyl-3,5-heptanedionato)manganese(III).

[0183] Examples of iron-containing compounds include tris(2,2,6,6-tetramethyl-3,5-heptanedionato)iron(III), iron oxocyclohexanecarboxylate(II), and iron chloride.

[0184] Examples of cobalt-containing compounds include dichloro[ethylenebis(diphenylphosphine)]cobalt, cobalt(II) bromide, cobalt(II) acetate, tris(1,3-diphenyl-1,3-propanedione)cobalt(III), and cyclopentylcobalt(II) acetate.

[0185] Examples of copper-containing compounds include copper(II) acetate, copper(II) monobutyl phthalate, copper(II) acetylacetonate, copper(I) heptanoate, and copper(II) 2-ethylhexanoate.

[0186] Zinc-containing compounds include zinc diisopropoxide, zinc(II) acetate, zinc(II) chloride, and zinc(II) 4-vinylbenzoate.

[0187] Compounds containing zirconium include dibutoxybis(ethylacetoacetate)zirconium(IV), di-n-butoxybis(2,4-pentanedionato)zirconium(IV), tetra-n-butoxyzirconium(IV), tetra-n-propoxyzirconium(IV), tetraisopropoxyzirconium(IV), aminopropyltriethoxyzirconium(IV), 2-(3,4-epoxycyclohexyl)ethyltrimethoxyzirconium(IV), γ-glycidoxypropyltrimethoxyzirconium(IV), 3-isocyanopropyltrimethoxyzirconium(IV), triethoxymono(2,4-pentanedionato)zirconium(IV), Examples of suitable cation exchangers include tri-n-propoxymono(2,4-pentanedionato)zirconium(IV), triisopropoxymono(2,4-pentanedionato)zirconium(IV), tri(3-methacryloxypropyl)methoxyzirconium(IV), tri(3-acryloxypropyl)methoxyzirconium(IV), zirconium acetate(IV), zirconium acetate oxide(IV), bis(2-ethylhexanoate)zirconium(II), tetra(2-ethylhexanoate)zirconium(IV), bis(2-ethylhexanoate)oxozirconium(IV), zirconium nitrate, zirconium chloride(IV), and zirconium carboxyethyl acrylate(IV).

[0188] Examples of compounds containing molybdenum include pentaethoxymolybdenum(V), molybdenum(VI) hexaethoxide, molybdenum(V) isopropoxide, molybdenum(II) acetate dimer, bis(acetylacetonato)molybdenum(IV) oxide, bis(2,2,6,6-tetramethyl-3,5-heptanedionato)molybdenum(VI) oxide, molybdenum 2-ethylhexanoate, molybdenum(V) chloride, and molybdenum(III) chloride.

[0189] Examples of compounds containing indium include tris(1,3-diphenyl-1,3-propanedione)indium(III), indium ethylbutyrate(III), indium acetate(III), and triisopropoxyindium(III).

[0190] Tin-containing compounds include tin(II) acetate, tin(IV) acetate, tin(II) acetylacetonate, tin(IV) tert-butoxide, tin tetra-n-butoxide, tin tetraisopropoxide, 4-fluorotin(II) acetate, and tin(II) 2-ethylhexanoate.

[0191] Examples of compounds containing hafnium include diisopropoxybis(2,4-pentanedionato)hafnium(IV), tetrabutoxyhafnium(IV), tetraisopropoxyhafnium(IV), tetraethoxyhafnium(IV), dichlorobis(cyclopentadienyl)hafnium(IV), hafnium chloride(IV), tetrakis(dimethylamido)hafnium(IV), tetrakis(ethylmethylamido)hafnium(IV), hafnium carboxyethyl acrylate, bis(cyclopentadienyl)hafnium(IV) dichloride, hafnium(IV) trifluoromethanesulfonate hydrate, and hafnium carboxyethyl acrylate(IV).

[0192] Examples of compounds containing tantalum include tantalum(V) methoxide, tantalum(V) ethoxide, tetrabutoxytantalum(IV), pentabutoxytantalum(V), pentaethoxytantalum(V), tantalum(V) chloride, pentakis(dimethylamino)tantalum(V), tris(diethylamido)(tert-butylimido)-tantalum(V), and bis(2-ethylhexanoate)tantalum(II).

[0193] Examples of compounds containing tungsten include tungsten(VI) ethoxide, tetrabutoxytungsten(IV), pentabutoxytungsten(V), pentamethoxytungsten(V), hexabutoxytungsten(VI), hexaethoxytungsten(VI), and dichlorobis(cyclopentadienyl)tungsten(IV).

[0194] Examples of compounds containing bismuth include bismuth(III)-n-butoxide, tri-t-amyloxybismuth(III), triethoxybismuth(III), bismuth(III) tris(β-diketonate), bismuth(III) neodecanoate, tris(2-naphthol)bismuth(III), bismuth(III) fluoride, bismuth(III) bromide, bismuth(III) iodide, bismuth(III) oxychloride, bismuth(III) acetate, bismuth(III) subsalicylate, bismuth(III) 2-ethylhexanoate, and bismuth(III) trifluoromethanesulfonate.

[0195] <(B) Solvent> The solvent (B) that can be used in the metal-containing film-forming composition of the present invention is not particularly limited as long as it can dissolve the metal compound (M) and other additives contained therein.

[0196] Specifically, for example, organic solvents described in paragraphs

[0091] to

[0092] of JP 2007-199653 A can be added. More specifically, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, 2-heptanone, cyclopentanone, cyclohexanone, and γ-butyrolactone, or a mixture containing one or more of these, are preferably used. Examples of other solvents that can be used include butanediol monomethyl ether, ethylene glycol monomethyl ether, butanediol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, butanediol monopropyl ether, propylene glycol monopropyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, 1-butanol, 2-butanol, 2-methylprop ... Examples of the alkyl ether include 1-methyl-1-propanol, 4-methyl-2-ethanol, acetone, tetrahydrofuran, toluene, hexane, ethyl acetate, cyclohexanone, methyl amyl ketone, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, diamyl ether, isoamyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, t-butyl acetate, t-butyl propionate, propylene glycol mono t-butyl ether acetate, methyl isobutyl ketone, and cyclopentyl methyl ether.

[0197] The blending amount of the (B) solvent is preferably 200 to 10,000 parts, more preferably 250 to 5,000 parts, per 100 parts by mass of the (M) metal compound.

[0198] <Other additives> Depending on the intended use of the metal-containing film-forming composition, the composition may contain at least one of (C) a crosslinking agent, (D) an acid generator, and (E) a surfactant.

[0199] Hereinafter, components that may be contained in the metal-containing film-forming composition other than the (M) metal compound and (B) organic solvent will be described.

[0200] [(C) Crosslinking agent] When the metal-containing film-forming composition is used for a resist underlayer film, a crosslinking agent (C) may be added to enhance curability and further suppress intermixing with the resist upperlayer film.

[0201] The crosslinking agent is not particularly limited, and a wide variety of 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, epoxy-based crosslinking agents, and phenol-based crosslinking agents. The (C) crosslinking agent can be used alone or in combination of two or more. When a crosslinking agent is added, the amount added is preferably 5 to 50 parts, more preferably 10 to 40 parts, per 100 parts of the (M) metal compound. Addition of 5 parts or more ensures sufficient curability and suppresses intermixing with the resist upper layer film. On the other hand, addition of 50 parts or less eliminates the risk of deterioration in dry etching resistance due to a low ratio of the (M) metal compound in the composition.

[0202] Specific examples of the melamine-based crosslinking agent include hexamethoxymethylated melamine, hexabutoxymethylated melamine, alkoxy- and / or hydroxy-substituted products thereof, and partial self-condensates thereof.

[0203] Specific examples of glycoluril crosslinking agents include tetramethoxymethylated glycoluril, tetrabutoxymethylated glycoluril, alkoxy and / or hydroxy substituted products thereof, and partial self-condensates thereof.

[0204] Specific examples of benzoguanamine-based crosslinking agents include tetramethoxymethylated benzoguanamine, tetrabutoxymethylated benzoguanamine, alkoxy- and / or hydroxy-substituted products thereof, and partial self-condensates thereof.

[0205] Specific examples of urea-based crosslinking agents include dimethoxymethylated dimethoxyethylene urea, its alkoxy and / or hydroxy substituted derivatives, and partial self-condensates thereof.

[0206] A specific example of the β-hydroxyalkylamide crosslinking agent is N,N,N',N'-tetra(2-hydroxyethyl)adipamide.

[0207] Specific examples of the isocyanurate crosslinking agent include triglycidyl isocyanurate and triallyl isocyanurate.

[0208] Specific examples of the aziridine crosslinking agent include 4,4'-bis(ethyleneiminocarbonylamino)diphenylmethane and 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate].

[0209] Specific examples of the oxazoline-based crosslinking agent include 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-tertbutyl-2-oxazoline, 2,2'-bis(2-oxazoline), 1,3-phenylenebis(2-oxazoline), 1,4-phenylenebis(2-oxazoline), and 2-isopropenyloxazoline copolymer.

[0210] Specific examples of epoxy-based crosslinking agents include 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.

[0211] Specific examples of phenol-based crosslinking agents include compounds represented by the following general formula (10). [ka] (wherein Q is a single bond or a q 1 R is a 2-valent hydrocarbon group. 16 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. 1 is an integer between 1 and 5.)

[0212] Q is a single bond or a q having 1 to 20 carbon atoms. 1 q is a valent hydrocarbon group. 1is an integer of 1 to 5, and more preferably 2 or 3. Specific examples of Q include methane, ethane, propane, butane, isobutane, pentane, cyclopentane, hexane, cyclohexane, methylpentane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, benzene, toluene, xylene, ethylbenzene, ethylisopropylbenzene, diisopropylbenzene, methylnaphthalene, ethylnaphthalene, and eicosane. 16 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. Specific examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, an isopentyl group, a hexyl group, an octyl group, an ethylhexyl group, a decyl group, and an eicosanyl group, and a hydrogen atom or a methyl group is preferred.

[0213] The compound represented by the above general formula (10) is preferably a hexamethoxymethylated product of triphenolmethane, triphenolethane, 1,1,1-tris(4-hydroxyphenyl)ethane, or tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, from the viewpoint of improving curability and film thickness uniformity.

[0214] <(D) Acid Generator> The metal-containing film-forming composition of the present invention may contain an acid generator, for example, a compound (photoacid generator) that generates an acid in response to actinic rays or radiation.

[0215] The photoacid generator may be any compound that generates an acid upon irradiation with high-energy rays. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate-type acid generators. Specific examples of the acid generator include those described in paragraphs

[0122] to

[0142] of JP2008-111103A, JP2009-080474A, and JP2015-026064A. I can't.

[0216] The acid generators can be used alone or in combination of two or more. When an acid generator is added, the amount added is preferably 0.05 to 50 parts, more preferably 0.1 to 10 parts, per 100 parts by mass of the (M) metal compound.

[0217] <(E) Surfactant> A surfactant (E) can be added to the metal-containing film-forming composition to improve the coating properties during spin coating. Examples of surfactants that can be used include those described in paragraphs

[0142] to

[0147] of JP-A-2009-269953. When a surfactant is added, the amount added is preferably 0.01 to 10 parts, more preferably 0.05 to 5 parts, per 100 parts by mass of the metal compound (M).

[0218] [Coating process] In the coating step, the metal-containing film-forming composition is applied directly or indirectly to a substrate. The method for applying the metal-containing film-forming composition is not particularly limited, and can be performed by any appropriate method, such as spin coating, casting coating, or roll coating. This results in the formation of a coated film, and the evaporation of the (B) solvent occurs, resulting in the formation of a metal-containing film.

[0219] The substrate onto which the metal-containing film-forming composition is applied is not particularly limited, and examples thereof include substrates such as Si, α-Si, p-Si, SiO2, SiN, SiON, W, TiN, and Al, as well as substrates with a work layer formed thereon. Examples of work layers include various low-k films and their stopper films, such as Si, SiO2, SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, and Al-Si, and can be formed to a thickness of typically 50 to 10,000 nm, particularly 100 to 5,000 nm. When forming a work layer, the substrate and work layer are made of different materials.

[0220] The lower limit of the average thickness of the metal-containing film formed is preferably 3 nm, more preferably 5 nm, and even more preferably 10 nm. The upper limit of the average thickness is preferably 500 nm, more preferably 200 nm, and even more preferably 60 nm. The average thickness is measured according to the method described in the Examples.

[0221] The method for manufacturing a semiconductor substrate preferably further includes a step of heating the coating film formed in the coating step (hereinafter also referred to as a "heating step"). Heating the coating film promotes the formation of a metal-containing film. More specifically, heating the coating film promotes the evaporation of the (B) solvent.

[0222] The coating film is usually heated in air, but may be heated in a nitrogen atmosphere. The lower limit of the heating temperature is preferably 150°C, more preferably 200°C. The upper limit of the heating temperature is preferably 600°C, more preferably 500°C. The lower limit of the heating time is preferably 15 seconds, more preferably 30 seconds. The upper limit of the heating time is preferably 1,200 seconds, more preferably 600 seconds.

[0223] [Organic resist intermediate film formation process] In this step, prior to the resist pattern forming step, an organic resist intermediate film can be formed directly or indirectly on the substrate having the metal-containing film formed in the coating step.

[0224] The organic interlayer film can be formed by coating a composition for forming an organic interlayer film, etc. Examples of methods for forming an organic resist interlayer film by coating a composition for forming an organic resist interlayer film include a method in which the composition for forming an organic resist interlayer film is directly or indirectly applied to a substrate having the metal-containing film, and the resulting coating film is then heated or exposed to light to cure it.

[0225] Organic resist interlayer materials that can be used for the organic resist interlayer include those already known as underlayers for three-layer resist methods or two-layer resist methods using a silicon resist composition, such as the 4,4'-(9-fluorenylidene)bisphenol novolac resin (molecular weight 11,000) described in JP 2005-128509 A, as well as numerous other resins, including novolac resins, known as underlayer (or intermediate) materials for two-layer and three-layer resist methods. Furthermore, if higher heat resistance than conventional novolacs is desired, a polycyclic skeleton such as 6,6'-(9-fluorenylidene)-di(2-naphthol) novolac resin can be incorporated, and polyimide-based resins can also be selected (e.g., JP 2004-153125 A).

[0226] The organic resist intermediate film can be formed on a substrate to be processed by spin coating or the like using a composition solution, similar to the photoresist composition. After forming the organic resist intermediate film by spin coating or the like, it is desirable to bake it to evaporate the organic solvent. The baking temperature is preferably in the range of 80 to 400°C, and the baking time is preferably in the range of 10 to 300 seconds.

[0227] Instead of the organic resist intermediate film material, an organic hard mask formed by a CVD method or an ALD method can also be used.

[0228] [Silicon-containing film formation process] In this step, prior to the resist pattern forming step, a silicon-containing film can be formed directly or indirectly on the substrate having the metal-containing film formed in the coating step.

[0229] The silicon-containing film can be formed by coating a silicon-containing film-forming composition, chemical vapor deposition (CVD), atomic layer deposition (ALD), or the like. Examples of methods for forming a silicon-containing film by coating a silicon-containing film-forming composition include a method in which the silicon-containing film-forming composition is applied directly or indirectly to the metal-containing film, and the resulting coating is cured by exposure and / or heating. Examples of commercially available silicon-containing film-forming compositions include "SHB-A940" (manufactured by Shin-Etsu Chemical Co., Ltd.). Silicon oxide films, silicon nitride films, silicon oxynitride films, and amorphous silicon films can be formed by chemical vapor deposition (CVD) or atomic layer deposition (ALD).

[0230] [Cleaning process] In this step, the peripheral edge of the substrate is washed with a cleaning liquid, which can suitably be the cleaning liquid of the present invention described above.

[0231] The cleaning method is not particularly limited, and any known cleaning method in semiconductor manufacturing processes, such as edge bead removal, back rinsing, etc., can be used. In the present invention, the step of cleaning a substrate on which a metal-containing film has been formed preferably includes applying the cleaning solution of the present invention along the peripheral edge of the substrate and removing the edge bead on the substrate (hereinafter, this may be referred to as "edge rinsing").

[0232] Typically, as shown in FIG. 1, first, a substrate 1 on which a metal-containing film 2 has been formed is rotated at a predetermined speed (FIG. 1A). Next, while a cleaning solution 4 is being discharged from the cleaning solution discharge nozzle 3, the cleaning solution discharge nozzle 3 is moved at a predetermined speed from the outer peripheral edge of the rotating substrate 1 toward the center of the substrate 1 (FIG. 1B). After the cleaning solution discharge nozzle 3 has moved a predetermined distance, it stops moving, and the cleaning solution 4 is further discharged for a predetermined time. Thereafter, the discharge of the cleaning solution 4 from the cleaning solution discharge nozzle 3 is stopped, and the coating film edge 2A is dried as necessary, thereby completing cleaning (FIG. 1C). The rotation speed of the substrate, the amount of cleaning solution discharged per unit time, the moving speed and moving distance of the cleaning solution discharge nozzle, the cleaning solution discharge time after the movement of the cleaning solution discharge nozzle is stopped, and the like may be appropriately set depending on the substrate size, the number, type, and thickness of the formed films, the cleaning area, and the like.

[0233] The number of times the edge is rinsed is not particularly limited, and it can be performed 1 to 20 times. Furthermore, two or more types of cleaning liquids can be applied during the edge rinse.

[0234] In edge rinsing, the cleaning liquid can be dropped in an amount of preferably 0.05 to 50 ml, more preferably 0.075 to 40 ml, and even more preferably 0.1 to 30 ml.

[0235] After the metal-containing film-forming composition is applied to the substrate, the cleaning step can be carried out with or without the heating step. When the cleaning step is carried out without the heating step after the application step, it is preferable to carry out the heating step after the cleaning step.

[0236] The metal-containing film formed by the above steps is preferably either a photoresist film or a resist underlayer film.

[0237] In addition, as shown in FIG. 2, the present invention can also be used as a cleaning liquid for reworking a metal-containing film 2 on a substrate 1 to reuse the substrate 1. A cleaning liquid discharge nozzle 3 is moved to the center of the substrate 1, and a cleaning liquid 4 is discharged onto the rotating substrate 1 for a predetermined period of time ((D) to (E) in FIG. 2). Thereafter, the discharge of the cleaning liquid 4 from the cleaning liquid discharge nozzle 3 is stopped, and the substrate is dried as necessary to complete the cleaning ((F) in FIG. 2). The rotation speed of the substrate, the amount of cleaning liquid discharged per unit time, the position at which the cleaning liquid is discharged, and the like can be appropriately set depending on the size of the substrate, the number, type, and thickness of the formed films, the cleaning area, and the like.

[0238] To evaluate the metal removal performance of the edge rinse, the substrate can be inspected for residual metals. Suitable commercially available approaches for evaluating trace metals generally involve inductively coupled plasma mass spectrometry (ICP-MS). Vapor phase decomposition-inductively coupled plasma mass spectrometry (VPD-ICP-MS) can be used to evaluate the substrate surface. Using this technique, residual metals can be determined per unit area of ​​the wafer surface along the edge.

[0239] In the present invention, when the metal-containing film is Zr-based, the amount of residual Zr is 100×10 10 atoms / cm 2 Less than 50 x 10 is preferable. 10 atoms / cm 2 Less than 10x10 is preferable. 10 atoms / cm 2 Even better: 5 x 10 10 atoms / cm 2 The following are particularly preferred:

[0240] <Pattern formation method using metal-containing resist underlayer film> In the resist pattern forming step, after the cleaning step, a resist pattern is formed directly or indirectly on the metal-containing film. Examples of methods for performing this step include a method using a resist composition, a method using a nanoimprinting method, and a method using a self-assembling composition. Examples of indirectly forming a resist pattern on the metal-containing film include forming a resist pattern on the silicon-containing film when the semiconductor substrate manufacturing method includes the silicon-containing film forming step.

[0241] After the above-mentioned cleaning step, the following can be exemplified as a method for directly or indirectly forming a resist pattern on the metal-containing film and transferring the resist pattern to a substrate to be processed.

[0242] (two-layer resist process) The present invention can provide a pattern formation method by a two-layer resist process using a metal-containing film, which includes forming a metal-containing film on a workpiece substrate using a metal-containing film-forming composition, forming a resist upper layer film on the metal-containing film using a photoresist material, exposing the resist upper layer film to light and developing it with a developer to form a pattern in the resist upper layer film, transferring the pattern to the metal-containing film by dry etching using the resist upper layer film with the pattern formed as a mask, and processing the workpiece substrate using the metal-containing film with the pattern formed as a mask to form a pattern on the workpiece substrate.

[0243] The resist top layer film in the two-layer resist process exhibits etching resistance to chlorine-based gases, and therefore, in the two-layer resist process, dry etching of the metal-containing film using the resist top layer film as a mask is preferably performed using an etching gas mainly containing a chlorine-based gas.

[0244] To ensure adhesion to the resist top layer, an adhesive film may be formed between the resist top layer and the metal-containing film. The adhesive film may be an organic film or a silicon-containing film containing polysiloxane.

[0245] (3-layer resist process) Furthermore, the present invention can provide a pattern formation method by a three-layer resist process using a metal-containing film, comprising: forming a metal-containing film on a workpiece substrate using a metal-containing film-forming composition; forming an organic resist intermediate film on the metal-containing film; forming a resist upper layer film on the organic resist intermediate film using a photoresist material; pattern-exposing the resist upper layer film and then developing it with a developer to form a pattern in the resist upper layer film; using the resist upper layer film with the pattern formed as a mask, transferring the pattern to the organic resist intermediate film by dry etching; using the organic resist intermediate film with the pattern transferred as a mask, transferring the pattern to the metal-containing film by dry etching; and processing the workpiece substrate using the metal-containing film with the pattern formed as a mask to form a pattern on the workpiece substrate.

[0246] The organic resist intermediate film in the three-layer resist process exhibits etching resistance against chlorine-based gases. Therefore, in the three-layer resist process, the dry etching of the metal-containing film using the organic resist intermediate film as a mask is preferably performed using an etching gas mainly containing a chlorine-based gas.

[0247] (4-layer resist process) Furthermore, the present invention provides a pattern formation method by a four-layer resist process using a metal-containing film, which includes forming a metal-containing film on a substrate to be processed using a metal-containing film-forming composition, forming an organic resist intermediate film on the metal-containing film, forming a silicon-containing film on the organic resist intermediate film, forming a resist upper layer film on the silicon-containing film using a photoresist material, pattern-exposing the resist upper layer film and then developing it with a developer to form a pattern in the resist upper layer film, using the resist upper layer film with the pattern formed as a mask to transfer the pattern to the silicon-containing film by dry etching, using the silicon-containing film with the pattern transferred as a mask to transfer the pattern to the organic resist intermediate film, using the organic resist intermediate film with the pattern transferred as a mask to transfer the pattern to the metal-containing film by dry etching, and processing the substrate to be processed using the metal-containing film with the pattern formed as a mask to form a pattern on the substrate to be processed.

[0248] Here, a pattern formation method using a four-layer resist process will be described with reference to FIG. 3. First, a metal-containing film 2 is formed on a substrate 1 using a metal-containing film-forming composition (FIG. 3A). Next, a cleaning solution 4 is discharged from a cleaning solution discharge nozzle 3 as described above to clean the metal-containing film 2 at the substrate edge (FIG. 3B). This completes cleaning of the coated film edge 2A (FIG. 3C). Next, an organic resist intermediate film 7, a silicon-containing film 6, and a resist upper layer film 5 are formed on the metal-containing film 2 (FIG. 3D). The exposed portion 8 of the resist upper layer film 5 is exposed to light to form a resist upper layer film pattern 5a (FIG. 3E-F). Then, using the resist upper layer film pattern 5a as a mask, a pattern is transferred to the silicon-containing film 6 by dry etching to form a silicon-containing film pattern 6a (FIG. 3G). Subsequently, an organic resist intermediate film pattern 7a and a metal-containing film pattern 2a are formed (FIG. 3H-I).

[0249] An inorganic hard mask may be formed as the inorganic hard mask intermediate film. In this case, at least a metal-containing film is formed on a workpiece using a metal-containing film-forming composition, an organic resist intermediate film is formed on the metal-containing film, an inorganic hard mask selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film is formed on the organic resist intermediate 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, the inorganic hard mask is etched using the resist upper layer film on which the pattern has been formed as a mask, the organic resist intermediate film is etched using the inorganic hard mask on which the pattern has been formed as a mask, the metal-containing film is etched using the organic resist intermediate film on which the pattern has been formed as a mask, and the workpiece is etched using the metal-containing film on which the pattern has been formed as a mask to form a pattern on the workpiece, thereby forming a semiconductor device circuit pattern on a substrate.

[0250] As described above, when forming an inorganic hard mask on a metal-containing film, a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiON film) can be formed by a CVD method, an ALD method, or the like. For example, methods for forming a silicon nitride film are described in Japanese Patent Application Laid-Open No. 2002-334869 and International Publication No. 2004 / 066377. The thickness of the inorganic hard mask is preferably 5 to 200 nm, more preferably 10 to 100 nm. Furthermore, a SiON film, which is highly effective as an anti-reflective coating, is most preferably used as the inorganic hard mask. Since the substrate temperature during SiON film formation is 300 to 500°C, the metal-containing film must be able to withstand temperatures of 300 to 500°C. The metal-containing film-forming composition used in the present invention has high heat resistance and can withstand high temperatures of 300 to 500°C, making it possible to combine an inorganic hard mask formed by a CVD method or an ALD method with a metal-containing film formed by a spin-coating method.

[0251] As described above, a photoresist film can be formed on an inorganic hard mask as a resist top layer. Alternatively, an organic antireflective coating (BARC) or adhesion film can be formed on the inorganic hard mask by spin coating, and then a photoresist film can be formed on top of that. In particular, when a SiON film is used as the inorganic hard mask, the two-layer antireflective coating consisting of the SiON film and the BARC can suppress reflection even in immersion lithography with a high NA exceeding 1.0. Another advantage of forming a BARC is that it reduces the footing of the photoresist pattern directly above the SiON film.

[0252] In the above-mentioned pattern forming method, the resist upper layer film may be either a positive or negative type, and the same photoresist compositions as those usually used can be used.

[0253] When forming a photoresist composition by spin coating, the resist is prebaked after application, preferably at 60 to 180°C for 10 to 300 seconds. Then, exposure is performed according to a conventional method, followed by post-exposure baking (PEB) and development to obtain a resist pattern. The thickness of the resist top layer film is not particularly limited, but is preferably 10 to 500 nm, and more preferably 20 to 400 nm.

[0254] Examples of exposure light include high energy rays with a wavelength of 300 nm or less, specifically excimer lasers with wavelengths of 248 nm, 193 nm, and 157 nm, soft X-rays with wavelengths of 3 to 20 nm, electron beams, and X-rays.

[0255] The resist upper layer film can be patterned by photolithography with a wavelength of 5 nm or more and 300 nm or less, direct writing with an electron beam, nanoimprinting, or a combination thereof, but EUV light is most preferred in the present invention.

[0256] In the pattern forming method, the development method is preferably alkaline development or development using an organic solvent.

[0257] Next, etching is performed using the obtained resist pattern as a mask. In the four-layer resist process, etching of the silicon-containing resist intermediate film and inorganic hard mask is performed using a fluorocarbon-based gas as a mask for the upper resist pattern. This results in the formation of a silicon-containing resist intermediate film pattern and an inorganic hard mask pattern.

[0258] Next, the organic resist intermediate film is etched using the silicon-containing resist intermediate film pattern or inorganic hard mask pattern as a mask, preferably using an etching gas mainly containing an oxygen-based gas.

[0259] Next, the metal-containing film is etched using the organic resist intermediate film pattern as a mask, preferably using an etching gas mainly containing a chlorine-based gas.

[0260] The next etching of the workpiece can also be done using standard methods. For example, if the workpiece is made of SiO2, SiN, or a silica-based low-k dielectric insulating film, etching is done using mainly fluorocarbon gases. When etching the substrate with fluorocarbon gases, the silicon-containing resist intermediate film pattern in the four-layer resist process is removed at the same time as the substrate is processed.

[0261] In the present invention, the metal-containing film obtained from the metal-containing film-forming composition is characterized by excellent etching resistance when etching the workpiece.

[0262] The workpiece (substrate) is not particularly limited, and may be a substrate such as Si, α-Si, p-Si, SiO2, SiN, SiON, W, TiN, or Al, or a substrate with a workpiece layer formed thereon. The workpiece layer may be a low-k film or a stopper film thereof, such as Si, SiO2, SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, or Al-Si, and may be formed to a thickness of typically 50 to 10,000 nm, particularly 100 to 5,000 nm. When forming a workpiece layer, the substrate and workpiece layer are made of different materials. [Example]

[0263] The present invention will be specifically explained below by showing synthesis examples, examples and comparative examples, but the present invention is not limited to these descriptions.

[0264] <Preparation of cleaning solution> Each cleaning solution was prepared by mixing the components in the proportions shown in Table 1.

[0265] [Table 1]

[0266] As the first solvent, the solvents shown in Table 2 below were used.

[0267] [Table 2]

[0268] As the second solvent, the solvents shown in Table 3 below were used.

[0269] [Table 3]

[0270] The organic acids used were those shown in Table 4 below.

[0271] [Table 4]

[0272] The chelating agent (c-1) used was acetylacetone (Tokyo Chemical Industry Co., Ltd., P0052), and the chelating agent (c-2) used was allyl acetoacetate (Tokyo Chemical Industry Co., Ltd., A1981).

[0273] <Preparation of Metal-Containing Film-Forming Composition> [Synthesis example of metal compounds] In the following synthesis examples, the following metal sources M: (M1) to (M3) and compound group H: (H1) to (H3) were used.

[0274] (M1): Ti(OBu)4: tetrabutyl orthotitanate (Tokyo Chemical Industry Co., Ltd., B0742) (M2): Hf(OBu)4: Hafnium(IV) n-butoxide (Sigma-Aldrich Corp, 667943) (M3): Zr(OBu)4: Zirconium(IV) tetrabutoxide (80% by mass solution in 1-butanol) (Tokyo Chemical Industry Co., Ltd., Z0016)

[0275] [ka]

[0276] [Synthesis Example 1: Synthesis of metal compound (m-1) for forming metal-containing film] Under a nitrogen atmosphere, a solution of 1.6 g of deionized water and 54.5 g of n-butanol was added dropwise to 40.5 g of n-butanol solution containing 28.4 g of tetrabutyl orthotitanate (M1) over 2 hours at room temperature while stirring. To the resulting solution, 11.2 g of compound group (H1) was added and stirred at room temperature for 30 minutes. This solution was concentrated under reduced pressure at 30°C and then further heated to 60°C and continued to be heated under reduced pressure until no more distillate was produced. When no more distillate was observed, 69.0 g of a PGMEA / PGME (70 / 30 weight ratio) solution was added and heated at 40°C under reduced pressure until no more IPA was produced, yielding a PGMEA / PGME solution of metal compound (m-1) for forming a metal-containing film. The concentration of components other than the solvent in the solution was 17% by mass.

[0277] [Synthesis of compounds (m-2) to (m-3)] Compounds (m-2) to (m-3) shown in Table 5 were obtained under the same reaction conditions as in Synthesis Example 1, except that the metal source M and compound group H were used in the amounts shown in Table 5.

[0278] [Table 5]

[0279] [Preparation of compound (m-4)] As the metal compound (m-4), tin(II) 2-ethylhexanoate (Tokyo Chemical Industry Co., Ltd., T3149) was used.

[0280] [Preparation of metal-containing film-forming composition (MUL-1)] The metal-containing film-forming compound (m-1) was dissolved in a mixed solvent of propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) in the proportions shown in Table 6, and the resulting solution was filtered through a 0.02 μm membrane filter to prepare a metal-containing film-forming composition (MUL-1).

[0281] [Preparation of Metal-Containing Film-Forming Compositions (MUL-2 to MUL-4)] Each drug solution was prepared in the same manner as in MUL-1, except that the type and content of each component was as shown in Table 6.

[0282] [Table 6]

[0283] <Metal cleaning performance evaluation> The metal-containing film-forming compositions (MUL-1 to MUL-4) prepared above were applied to a silicon substrate by spin coating. While rotating at 1500 rpm, a cleaning solution (MER-1 to MER-25, Comparative Example MER-1 to MER-2) was dispensed at a rate of 2 ml / sec. The cleaning solution was then dispensed at a rate of 2 ml / sec for 10 seconds at a position 2 mm from the outer edge toward the center of the substrate. The substrate was then rotated at 1500 rpm for 30 seconds. The substrate was then heated at 450°C for 60 seconds to obtain an evaluation substrate A on which a metal-containing film with an average thickness of 30 nm was formed. The residual metal amount (×10) of the outer edge (front and back surfaces 0.3 mm from the edge) of the obtained evaluation substrate A was then measured using vapor-phase decomposition-inductively coupled plasma mass spectrometry (VPD-ICP-MS). 10 atoms / cm 2 ) was measured.

[0284] Evaluation substrate B, on which each metal-containing film with an average thickness of 30 nm was formed, was obtained in the same manner as for obtaining evaluation substrate A, except that OK73 thinner was used instead of the cleaning solutions (MER-1 to MER-25). OK73 thinner is a mixed solvent of propylene glycol monomethyl ether and propylene glycol methyl ether acetate.

[0285] The metal cleaning ability was evaluated as "A" when the amount of metal constituting the metal compound for forming a metal-containing film detected on evaluation substrate A was less than 30% of that on evaluation substrate B, "B" when it was 30% or more but less than 50%, and "C" when it was 50% or more. The results are shown in Table 7.

[0286] [Table 7]

[0287] As shown in Table 7, the cleaning solution of the present invention was found to have superior metal removal properties compared to Comparative Examples 1-1 and 1-2, which used Comparative Examples MER-1 and MER-2. It is believed that the cleaning solution of the present invention contains a second solvent (A-2) with a normal boiling point of 160°C or higher but lower than 500°C, which inhibits drying of the cleaning solution and further improves the metal removal effect of the organic acid. Among the second solvents, cleaning solutions containing hydroxyl-free chain carboxylic acid esters and chain ethers (Y-2 to Y-4) exhibited excellent metal removal properties. It is believed that the use of an organic solvent containing no hydroxyl group inhibits the esterification reaction of the acid in the cleaning solution, thereby preventing deterioration of the metal removal properties of the cleaning solution. Furthermore, Examples 1-24 and 1-25, which used cleaning solutions MER-24 and MER-25 containing compounds (c-1) and (c-2) with a β-diketone structure as chelating agents, exhibited superior cleaning properties compared to Examples 1-9 and 1-10, which used cleaning solutions MER-9 and MER-10 without a chelating agent.

[0288] <Drainage stability> Equal amounts of the cleaning solutions (MER-1 to 25) prepared above were mixed with the metal-containing film-forming compositions (MUL-1 to 4), the resist underlayer film-forming composition (SOC-1), the silicon-containing film-forming composition (SOG-1), and the photoresist composition (PR-1) to prepare mixed solutions. The mixed solutions were left to stand at 23°C for one week, and the presence or absence of precipitates and turbidity was visually inspected. The effluent stability was evaluated as "good" if the mixed solutions did not show any precipitation or turbidity after standing at 23°C for one week, and "poor" if precipitation or turbidity was observed. The results are shown in Table 12.

[0289] The following materials were used for the composition for forming a resist underlayer film (SOC-1), the composition for forming a silicon-containing film (SOG-1), and the photoresist composition (PR-1).

[0290] The composition for forming a resist underlayer film (SOC-1) was prepared by dissolving a polymer indicated as the organic underlayer film polymer (SOP1) and 0.1 mass % of FC-4430 (manufactured by Sumitomo 3M Limited) in an organic solvent in the proportions shown in Table 8, and filtering the resulting mixture through a fluororesin filter having a pore size of 0.2 μm.

[0291] [Table 8]

[0292] Table 9 shows the structural formula of the organic underlayer polymer (SOP1) used.

[0293] [Table 9]

[0294] The silicon-containing film-forming composition (SOG-1) was prepared by dissolving a polymer represented by the silicon-containing intermediate film polymer (SiP1) and a thermal crosslinking catalyst (CAT1) in an organic solvent containing 0.1 mass% of FC-4430 (manufactured by Sumitomo 3M) in the proportions shown in Table 10, and filtering the solution through a fluororesin filter with a pore size of 0.1 μm.

[0295] [Table 10]

[0296] The structural formulae of the silicon-containing interlayer polymer (SiP1) and thermal crosslinking catalyst (CAT1) used are shown below.

[0297] [ka]

[0298] Photoresist composition (PR-1) was prepared by dissolving the polymer, quencher, sensitizer, and surfactant shown below in an organic solvent containing 0.25% by mass of FC-4430 (manufactured by Sumitomo 3M Limited) in the proportions shown in Table 11, and filtering the solution through a fluororesin filter with a pore size of 0.1 μm.

[0299] [ka]

[0300] [ka] Surfactant: 3M FC-4430

[0301] [Table 11] Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) CyHO (cyclohexanone) PGME (Propylene Glycol Monomethyl Ether)

[0302] [Table 12]

[0303] As shown in the results in Table 12, it was found that the cleaning solution of the present invention has excellent drainage stability.

[0304] <Hump height evaluation> As shown in Figure 4, the metal-containing film-forming composition 2' (MUL-1 to MUL-4) prepared above was applied to a silicon substrate 1 by spin coating (Figure 4A). While rotating the substrate at 1500 rpm, a cleaning solution discharge nozzle 3 was moved 2 mm from the outer edge of the substrate toward the center, and cleaning solution 4 (MER-1 to MER-25, comparative examples MER-1 and MER-2) was discharged at a rate of 2 ml / sec (Figure 4B). The cleaning solution was then discharged at a rate of 2 ml / sec for 10 seconds at a position 2 mm from the outer edge toward the center of the substrate (Figure 4C). The substrate was then rotated at 1500 rpm for 30 seconds. The substrate was then heated at 450 °C for 60 seconds to obtain an evaluation substrate A on which a metal-containing film with an average thickness of 30 nm was formed. Next, the height of the hump at the edge 2A of the coating film, which is near the boundary with the film removal area (Hump 8 in Figure 4(D)), was measured using a stylus film thickness meter (device name "Alpha Step", manufactured by KLA-Tencor).

[0305] Evaluation substrate B, on which metal-containing films with an average thickness of 30 nm were formed, was obtained in the same manner as in obtaining evaluation substrate A, except that OK73 thinner was used as the cleaning liquid instead of the cleaning liquid (MER-1 to 25).

[0306] When the hump height of evaluation substrate A was less than 50% of that of evaluation substrate B, it was rated as "A", when it was 50 to 80%, it was rated as "B", and when it was more than 80%, it was rated as "C". The results are shown in Table 13.

[0307] [Table 13]

[0308] As shown in the results in Table 13, it was found that the cleaning solution of the present invention can suppress hump height compared to OK73 thinner. In particular, cleaning solutions containing second solvents (Y-1) to (Y-6) with high surface tension (e.g., MER-1 to MER-9) showed excellent hump suppression. On the other hand, no improvement in hump was observed in Comparative Example MER-1, which did not contain a second solvent. Comparative Example MER-2, which contained a second solvent (Y-1) but no organic acid, showed inferior hump suppression compared to MER-5, which contained an organic acid. In other words, it is thought that the inclusion of an organic acid increases compatibility with the metal-containing film and improves hump suppression. It is believed that the cleaning solution of the present invention exhibits excellent hump suppression due to the synergistic effect of containing both the organic acid and the second solvent with a normal boiling point of 160°C or higher and lower than 500°C.

[0309] Based on the above, the cleaning solution of the present invention is a cleaning solution containing (A) a solvent and (B) an organic acid, where the (A) solvent contains at least one first solvent (A-1) having a standard boiling point below 160°C and at least one second solvent (A-2) having a standard boiling point of 160°C or higher but lower than 500°C. Therefore, a cleaning solution can be provided that exhibits excellent cleaning properties, hump suppression, and drainage stability, such as for removing the metal-containing film-forming composition from the peripheral edge of a substrate when the metal-containing film-forming composition is applied to the substrate. Substrate cleaning methods and metal-containing film formation methods using this cleaning solution employ a cleaning solution with excellent cleaning properties, hump suppression, and drainage stability, allowing for efficient formation of a desired resist underlayer film. These cleaning solutions are suitable for use in the manufacture of semiconductor devices, where further miniaturization is expected to continue.

[0310] This specification includes the following inventions.

[0311] [1]: A cleaning liquid for a metal-containing film-forming composition, the cleaning liquid comprising (A) a solvent and (B) an organic acid, wherein the solvent (A) comprises at least one first solvent (A-1) having a standard boiling point of less than 160°C, and at least one second solvent (A-2) having a standard boiling point of 160°C or higher but lower than 500°C.

[0312] [2]: The cleaning solution according to the above [1], wherein the second solvent (A-2) is a chain ester, a chain ether, or a combination thereof.

[0313] [3]: The cleaning solution according to [2] above, wherein the esters are carboxylic acid esters.

[0314] [4]: The cleaning solution according to the above [2] or [3], wherein the ether is a (poly)alkylene glycol dibenzyl ether or a (poly)phenyl ether.

[0315] [5]: The cleaning liquid according to any one of the above [1] to [4], wherein the second solvent (A-2) has a surface tension of 29.0 mN / m or more.

[0316] [6]: The cleaning solution according to any one of the above [1] to [5], wherein the content of the first solvent (A-1) in the solvent (A) is 30% by mass or more and 98% by mass or less, and the content of the second solvent (A-2) in the solvent (A) is 2% by mass or more and 70% by mass or less.

[0317] [7]: The cleaning liquid according to any one of the above [1] to [6], wherein the (B) organic acid is a carboxylic acid.

[0318] [8]: The cleaning solution according to any one of the above [1] to [7], wherein the content of the (B) organic acid is 1 to 70 mass % relative to the total mass of the cleaning solution.

[0319] [9]: The cleaning solution according to any one of the above [1] to [8], further comprising (C) a compound having a β-diketone as a chelating agent.

[0320]

[10] : The cleaning solution according to the above [9], wherein the content of the chelating agent (C) is 0.1 to 10% by mass relative to the total mass of the cleaning solution.

[0321]

[11] : A method for cleaning a substrate, comprising a step of cleaning a peripheral portion of a substrate to which a metal-containing film-forming composition has been directly or indirectly applied, with the cleaning liquid according to any one of [1] to

[10] above.

[0322]

[12] : A method for forming a metal-containing film, comprising the steps of: applying a metal-containing film-forming composition directly or indirectly to a substrate; and cleaning the metal-containing film-forming composition from the peripheral edge of the substrate with the cleaning liquid according to any one of [1] to

[10] above, wherein the metal-containing film-forming composition contains a metal compound and a solvent.

[0323] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention. [Explanation of symbols]

[0324] 1...substrate to be processed (substrate, silicon substrate), 2...metal-containing film, 2'...Metal-containing film forming composition, 2A...Coating film edge, 2a...Metal-containing film pattern, 3...cleaning solution discharge nozzle, 4...cleaning solution, 5...resist upper layer film, 5a...resist upper layer film pattern, 6...silicon-containing film, 6a...silicon-containing film pattern, 7...organic resist intermediate film, 7a...organic resist intermediate film pattern, 8...exposed portion, Hump8...Hump height.

Claims

1. A cleaning solution for a metal-containing film-forming composition, (A) a solvent; and (B) a cleaning solution containing an organic acid, The cleaning solution is characterized in that the solvent (A) comprises at least one first solvent (A-1) having a normal boiling point of less than 160°C and at least one second solvent (A-2) having a normal boiling point of 160°C or higher but lower than 500°C.

2. 2. The cleaning solution according to claim 1, wherein the second solvent (A-2) is a chain ester, a chain ether, or a combination thereof.

3. 3. The cleaning solution according to claim 2, wherein the esters are carboxylic acid esters.

4. 3. The cleaning solution according to claim 2, wherein the ethers are (poly)alkylene glycol dibenzyl ethers or (poly)phenyl ethers.

5. 2. The cleaning solution according to claim 1, wherein the second solvent (A-2) has a surface tension of 29.0 mN / m or more.

6. 2. The cleaning solution according to claim 1, wherein a content of the first solvent (A-1) in the solvent (A) is 30% by mass or more and 98% by mass or less, and a content of the second solvent (A-2) in the solvent (A) is 2% by mass or more and 70% by mass or less.

7. 2. The cleaning solution according to claim 1, wherein the organic acid (B) is a carboxylic acid.

8. 2. The cleaning solution according to claim 1, wherein the content of the organic acid (B) is 1 to 70% by mass based on the total mass of the cleaning solution.

9. The cleaning solution according to claim 1, further comprising (C) a compound having a β-diketone as a chelating agent.

10. 10. The cleaning solution according to claim 9, wherein the content of the chelating agent (C) is 0.1 to 10% by mass relative to the total mass of the cleaning solution.

11. 11. A method for cleaning a substrate, comprising: a step of cleaning a peripheral portion of a substrate to which a metal-containing film-forming composition has been directly or indirectly applied, with the cleaning solution according to claim 1 .

12. 11. A method for forming a metal-containing film, comprising: a step of applying a metal-containing film-forming composition directly or indirectly to a substrate; and a step of cleaning the metal-containing film-forming composition from a peripheral portion of the substrate with the cleaning solution according to claim 1, wherein the metal-containing film-forming composition contains a metal compound and a solvent.

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