Method for producing a fine metal structure

Abstract

Methods for producing a fine metal structure, comprising wet etching or dry etching, Rinsing to remove contaminants that have formed after dry etching or wet etching, followed by rinsing with a processing fluid, Rinse with water after rinsing with the processing fluid, and dry after rinsing with water. wherein the processing fluid comprises at least one compound selected from the group consisting of: an imidazolium halide with an alkyl group containing 12, 14 or 16 carbon atoms; a pyridinium halide with an alkyl group containing 14 or 16 carbon atoms; a betaine compound with an alkyl group containing 12, 14 or 16 carbon atoms; and an amine oxide compound with an alkyl group containing 14, 16 or 18 carbon atoms, wherein the content of at least one compound in the processing fluid is from 10 ppm to 10 wt%.

Description

Technical field

[0001] The present invention relates to a method for producing a fine metal structure in which a processing fluid is used to suppress pattern breakdown of the fine metal structure. State of the art

[0002] Photolithography has been used as a method for creating and processing devices with fine structures, employed in a wide range of fields, including semiconductor devices, printed circuit boards, and the like. In these fields, significant advances are being made in semiconductor device size reduction, integration level increase, and speed increase, coupled with highly demanding performance requirements. This leads to a continuous miniaturization and increase in the aspect ratio of the photoresist pattern used in photolithography. However, the progress in miniaturizing photoresist patterns causes pattern breakdown, a serious problem.

[0003] It is known that when a photoresist sample dries in the presence of a processing fluid used in wet processing (primarily a rinsing treatment to wash away the developer solution) after development, the collapse of the photoresist sample is caused by the stress resulting from the surface tension of the processing fluid. To prevent the collapse of the photoresist sample, methods have been proposed, such as replacing the rinsing fluid with a fluid having a low surface tension, using a non-ionic surfactant, a compound soluble in an alcohol solvent, or the like (see, for example, patent documents 1 and 2), and a method of hydrophobizing the surface of the photoresist sample (see, for example, patent document 3).

[0004] In a fine structure formed by photolithography from a metal, metal nitride, metal oxide or the like (which may be referred to below as a “fine metal structure” and where a metal, metal nitride, metal oxide or the like may be referred to below collectively as a “metal”), the strength of the metal itself forming the structure is greater than the strength of the photoresist pattern itself or the bond strength between the photoresist pattern and the substrate, and therefore a breakdown of the structural pattern compared to the photoresist pattern hardly occurs.With the advances in miniaturization, integration, and speed of semiconductor devices and micromachines, pattern breakdown due to miniaturization and increasing aspect ratio of the photoresist pattern becomes a serious problem. The fine metal structure has a surface condition completely different from that of the photoresist pattern, which is an organic material, and therefore there is no effective measure to prevent pattern breakdown.Accordingly, the current situation is such that the degree of freedom in designing the pattern for manufacturing a semiconductor device or a micromachine with reduced size, increased integration level, and increased speed is considerably restricted, since the pattern is necessarily designed to prevent pattern breakdown. Patent document 4 describes a cleaning agent for lithography and methods for producing resist patterns using this agent. State-of-the-art documents, patent documents Patent document 1: JP 2004 - 184 648 A Patent document 2: JP 2005 - 309 260 A Patent document 3: JP 2006 - 163 314 A Patent document 4: US 2009 / 0 004 608 A1 Summary of the invention Problems to be solved by the invention

[0005] As described above, the current situation is such that in the field of fine metal structures, such as semiconductor devices and micromachines, no effective technique for suppressing pattern breakdown is known.

[0006] The present invention was developed under these circumstances and an object of the present invention is to provide a method for producing a fine metal structure, such as a semiconductor device and a micromachine, in which a processing fluid is used which can suppress pattern breakdown of the fine metal structure. Means of solving the problems

[0007] As a result of intensive investigations carried out by the inventors to solve the problem, it was found that the problem can be solved by a process comprising wet or dry etching, rinsing of impurities formed after dry or wet etching, subsequent rinsing with a processing fluid, rinsing with water after rinsing with the processing fluid, and drying after rinsing with water, wherein the processing fluid comprises at least one compound selected from the group consisting of: an imidazolium halide with an alkyl group containing 12, 14, or 16 carbon atoms; a pyridinium halide with an alkyl group containing 14 or 16 carbon atoms; a betaine compound with an alkyl group containing 12, 14, or 16 carbon atoms;and an amine oxide compound with an alkyl group containing 14, 16 or 18 carbon atoms, wherein the content of the at least one compound in the processing liquid is from 10 ppm to 10 wt%.

[0008] The present invention was made on the basis of this knowledge. The main subject matter of the present invention is as defined in the attached claims.

[0009] In the description, the cases where the number of carbon atoms in the alkyl group is 12, 14, 16 and 18 can in some cases be referred to as C12, C14, C16 and C18 respectively. Effect of the invention

[0010] According to the invention, a method for producing a fine metal structure, such as a semiconductor device and a micromachine, is provided, in which a processing fluid is used that can suppress pattern breakdown of the fine metal structure. Brief description of the drawings [ Fig. 1] The figure includes schematic cross-sectional views of each manufacturing step of fine metal structures produced in Examples 1 to 7 and 14 to 18, Reference Examples 8 to 13 and Comparative Examples 1 to 14. Embodiments for carrying out the invention

[0011] The processing fluid is used to suppress pattern breakdown of a fine metal structure and contains at least one compound selected from an imidazolium halide with a C12, C14 or C16 alkyl group, a pyridinium halide with a C14 or C16 alkyl group, a betaine compound with a C12, C14 or C16 alkyl group and an amine oxide compound with a C14, C16 or C18 alkyl group.

[0012] It is assumed that the imidazolium halide with a C12, C14, or C16 alkyl group, the pyridinium halide with a C14 or C16 alkyl group, the betaine compound with a C12, C14, or C16 alkyl group, and the amine oxide compound with a C14, C16, or C18 alkyl group used in the processing fluid will adsorb onto the metal material used in the fine metal structure pattern, thereby rendering the surface of the pattern hydrophobic. In this case, hydrophobicity means that the contact angle of the metal surface treated with the processing fluid with respect to water is 70° or greater.

[0013] Beispiele für das Imidazoliumhalogenid mit einer C12-, C14- oder C16-Alkylgruppe umfassen 1-Dodecyl-3-methylimidazoliumchlorid, 1-Dodecyl-3-methylimidazoliumbromid, 1-Dodecyl-3-methylimidazoliumiodid, 1-Methyl-3-dodecylimidazoliumchlorid, 1-Methyl-3-dodecylimidazoliumbromid, 1-Methyl-3-dodecylimidazoliumiodid, 1-Dodecyl-2-methyl-3-benzylimidazoliumchlorid, 1-Dodecyl-2-methyl-3-benzylimidazoliumbromid, 1-Dodecyl-2-methyl-3-benzylimidazoliumiodid, 1-Tetradecyl-3-methylimidazoliumchlorid, 1-Tetradecyl-3-methylimidazoliumbromid, 1-Tetradecyl-3-methylimidazoliumiodid, 1-Methyl-3-tetradecylimidazoliumchlorid, 1-Methyl-3-tetradecylimidazoliumbromid, 1-Methyl-3-tetradecylimidazoliumiodid, 1-Hexadecyl-3-methylimidazoliumchlorid, 1-Hexadecyl-3-methylimidazoliumbromid, 1-Hexadecyl-3-methylimidazoliumiodid, 1-Hexadecyl-4-methylimidazoliumchlorid, 1-Hexadecyl-4-methylimidazoliumbromid, 1-Hexadecyl-4-methylimidazoliumiodid, 1-Methyl-3-hexadecylimidazoliumchlorid,1-Methyl-3-hexadecylimidazolium bromide and 1-methyl-3-hexadecylimidazolium iodide, and in particular 1-dodecyl-3-methylimidazolium chloride, 1-tetradecyl-3-methylimidazolium chloride and 1-hexadecyl-3-methylimidazolium chloride are preferred.

[0014] Examples of the pyridinium halide with a C14 or C16 alkyl group include tetradecylpyridinium chloride, tetradecylpyridinium bromide, tetradecylpyridinium iodide, hexadecylpyridinium chloride, hexadecylpyridinium bromide, hexadecylpyridinium iodide, 1-tetradecyl-4-methylpyridinium chloride, 1-tetradecyl-4-methylpyridinium bromide, 1-tetradecyl-4-methylpyridinium iodide, 1-hexadecyl-4-methylpyridinium chloride, 1-hexadecyl-4-methylpyridinium bromide, and 1-hexadecyl-4-methylpyridinium iodide, and in particular, tetradecylpyridinium chloride, hexadecylpyridinium chloride, 1-tetradecyl-4-methylpyridinium chloride, and 1-hexadecyl-4-methylpyridinium iodide. preferred.

[0015] The alkyl group with 12 carbon atoms is preferably a dodecyl group, the alkyl group with 14 carbon atoms is preferably a tetradecyl group, the alkyl group with 16 carbon atoms is preferably a hexadecyl group, and the alkyl group with 18 carbon atoms is preferably an octadecyl group. The compound containing the linear alkyl group can be adsorbed onto a metal material with high density.

[0016] In particular, examples of the betaine compound with a C12, C14 or C16 alkyl group include dodecyldimethylaminoacetic acid betaine, tetradecyldimethylaminoacetic acid betaine, hexadecyldimethylaminoacetic acid betaine and palm oil fatty acid amide propyl betaine, and dodecyldimethylaminoacetic acid betaine and palm oil fatty acid amide propyl betaine are particularly preferred.

[0017] Preferred examples of the amine oxide compound with a C14, C16 or C18 alkyl group include dimethyltetradecylamine oxide, dimethylhexadecylamine oxide and dimethyloctadecylamine oxide.

[0018] The imidazolium halide with a C12, C14 or C16 alkyl group is preferably an imidazolium halide with a C14 or C16 alkyl group and more preferably an imidazolium halide with a C16 alkyl group.

[0019] The pyridinium halide with a C14 or C16 alkyl group is preferably a pyridinium halide with a C16 alkyl group.

[0020] The amine oxide compound with a C14, C16 or C18 alkyl group is preferably an amine oxide compound with a C16 or C18 alkyl group and more preferably an amine oxide compound with a C18 alkyl group.

[0021] The processing fluid preferably further contains water and is preferably an aqueous solution. Preferred examples of the water include water from which metal ions, organic impurities, particles and the like have been removed by distillation, ion exchange, filtration, adsorption treatment or the like, and particularly preferred examples include pure water and ultrapure water.

[0022] The processing fluid contains at least one compound selected from the imidazolium halide with a C12, C14 or C16 alkyl group, the pyridinium halide with a C14 or C16 alkyl group, the betaine compound with a C12, C14 or C16 alkyl group and the amine oxide compound with a C14, C16 or C18 alkyl group described above, preferably contains water and may contain various types of additives commonly used in processing fluids in a range that does not impair the advantages of the processing fluid.

[0023] The content of the compound selected from the imidazolium halide with a C12, C14 or C16 alkyl group, the pyridinium halide with a C14 or C16 alkyl group, the betaine compound with a C12, C14 or C16 alkyl group and the amine oxide compound with a C14, C16 or C18 alkyl group (where the total content is the total content if several compounds are included) in the processing liquid is preferably 10 ppm to 10%.

[0024] If the concentration of the compound is within this range, its advantages can be sufficiently preserved. Considering handling, cost-effectiveness, and foaming properties, the compound is preferably used at a lower concentration of 5% or less, more preferably from 10 to 2000 ppm, and even more preferably from 10 to 1000 ppm. If the compound does not exhibit sufficient solubility in water, causing phase separation, an organic solvent, such as an alcohol, may be added, and an acid or alkali may be added to increase solubility.Even if the processing fluid exhibits only a white turbidity without phase separation, it can still be used within a range that does not compromise its advantages, and it can be used while stirring to homogenize it. Furthermore, to prevent the white turbidity of the processing fluid, it can be used after adding an organic solvent, such as an alcohol, acid, or alkali, similarly to the above case.

[0025] The processing fluid can advantageously be used to suppress pattern breakdown in a fine metal structure, such as in a semiconductor device or micromachine. Preferred examples of the fine metal structure pattern include those containing tungsten (W).

[0026] In some cases, the fine metal structure can be formed as a pattern on an insulating film species, such as SiO2 (a silicon oxide film) and TEOS (a tetraethoxyorthosilane), or the insulating film species is included as part of the fine metal structure.

[0027] The processing fluid exhibits excellent pattern breakdown suppression not only for ordinary fine metal structures but also for further reduced fine metal structures with a higher aspect ratio. The aspect ratio referred to here is a value calculated as (pattern height / pattern width), and the processing fluid demonstrates excellent pattern breakdown suppression for patterns with a high aspect ratio of 3 or more, and furthermore, 7 or more.The processing fluid exhibits excellent pattern breakdown suppression for a finer pattern with a pattern size (pattern width) of 300 nm or less, furthermore 150 nm or less and furthermore 100 nm or less, and with a pattern size of 50 nm or less and a line / spacing ratio of 1:1, and similarly for a finer pattern with a pattern spacing of 300 nm or less, furthermore 150 nm or less, furthermore 100 nm or less and furthermore 50 nm or less and a cylindrical hollow or cylindrical solid structure. Method for producing a fine metal structure

[0028] The method for producing a fine metal structure according to the present invention comprises, after wet or dry etching, a rinsing step using the processing fluid. In particular, it is preferred in the rinsing step that the pattern of the fine metal structure is brought into contact with the processing fluid by immersion, spray ejection, spraying, or the like, whereupon the processing fluid is replaced by water and the fine metal structure is dried.In the case where the fine metal structure pattern and the processing fluid are brought into contact by immersion, the immersion time is preferably 10 seconds to 30 minutes, more preferably 15 seconds to 20 minutes, further preferably 20 seconds to 15 minutes, and particularly preferably 30 seconds to 10 minutes. The temperature conditions are preferably 10 to 60 °C, more preferably 15 to 50 °C, further preferably 20 to 40 °C, and particularly preferably 25 to 40 °C. The fine metal structure pattern can be rinsed with water before being brought into contact with the processing fluid. The contact between the fine metal structure pattern and the processing fluid suppresses pattern collapse when one pattern is in contact with the adjacent pattern by hydrophobizing the surface of the pattern.

[0029] The processing fluid can be used without specific restriction to a manufacturing process for a fine metal structure, regardless of the type of fine metal structure, as long as the manufacturing process includes a wet or dry etching step, then a wet processing step (such as etching, cleaning, or rinsing to remove the cleaning fluid), and then a drying step. For example, the processing fluid can advantageously be used after the etching step in the manufacturing process for a semiconductor device or a micromachine, e.g., (i) after the wet etching of an insulating film in the vicinity of an electrically conductive film in the manufacture of a DRAM-type semiconductor device (see, e.g.,JP-A-2000-196038 and JP-A-2004-288710), (ii) after a rinsing step to remove impurities formed after dry etching or wet etching during the processing of a gate electrode in the manufacture of a semiconductor device having a transistor with a rib in the form of strips (see, e.g., JP-A-2007-335892), and (iii) after a rinsing step to remove impurities formed after etching to form a cavity by removing a sacrificial layer formed from an insulating film through a through-hole in an electrically conductive film during the formation of a cavity of a micromachine (electrodynamic micromachine) (see, e.g., JP-A-2009-122031). Example

[0030] The present invention is described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the examples. Production of a processing fluid

[0031] Processing fluids for suppressing pattern breakdown of a fine metal structure were prepared according to the formulation compositions (wt%) shown in Table 1. Table 1 Art Number of carbon atoms in the alkyl group* 1 Salary Processing fluid 1 1-Dodecyl-3-methylimidazolium chloride C12 5000 ppm Processing fluid 2 1-Tetradecyl-3-methylimidazolium chloride C14 1000 ppm Processing fluid 3 1-Hexadecyl-3-methylimidazolium chloride C16 500 ppm Processing fluid 4 Tetradecylpyridinium chloride C14 3000 ppm Processing fluid 5 1-Tetradecyl-4-methylpyridinium chloride C14 1500 ppm Processing fluid 6 Hexadecylpyridinium chloride C16 300 ppm Processing fluid 7 1-Hexadecyl-4-methylpyridinium chloride C16 100 ppm Processing fluid 8 Tetradecyltrimethylammonium chloride C14 5000 ppm Processing fluid 9 Benzyldimethyltetradecyl ammonium chloride C14 2000 ppm Processing fluid 10 Hexadecyltrimethylammonium chloride C16 200 ppm Processing fluid 11 Benzyldimethylhexadecyl ammonium chloride C16 500 ppm Processing fluid 12 Octadecyltrimethylammonium chloride C18 100 ppm Processing fluid 13 Benzyldimethyloctadecyl ammonium chloride C18 10 ppm Processing fluid 14 Dodecyldimethylaminoacetic acid betaine C12 10 % Processing fluid 15 Palm oil fatty acid amide propyl betaine C12, C14, C16 100 ppm Processing fluid 16 Dimethyltetradecylamine oxide C14 1 % Processing fluid 17 Dimethylhexadecylamine oxide C16 5000 ppm Processing fluid 18 Dimethyloctadecylamine oxide C18 50 ppm *1: Number of carbon atoms in the alkyl group of the compounds Examples 1 to 7 and 14 to 18, as well as reference examples 8 to 13

[0032] As it is in the Fig. As shown in Figure 1(a), silicon nitride 103 (thickness: 100 nm) and silicon oxide 102 (thickness: 1200 nm) were formed as films on a silicon substrate 104, then a photoresist 101 was formed and the photoresist 101 was exposed and developed, forming a circular and annular aperture 105 (diameter: 125 nm, distance between circles: 50 nm), as shown in the Fig.Figure 1(b) shows that the silicon oxide 102 was etched by dry etching with the photoresist 101 as a mask, forming a cylindrical hole 106 that reached the silicon nitride layer 103, as shown in the Fig. Figure 1(c) shows that the photoresist 101 was then removed by ashing, providing a structure having the silicon oxide 102, with the cylindrical hole 106 reaching the silicon nitride layer 103, as shown in the Fig. 1(d) is shown. The cylindrical hole 106 of the resulting structure was filled with tungsten as metal 107 ( Fig. 1(e)) and an excess part of the metal (tungsten) 107 was removed by chemical-mechanical polishing (CMP), providing a structure that featured the silicon oxide 102 with an embedded cylindrical depression of the metal (tungsten) 108, as shown in the Fig.1 (f) is shown. The silicon oxide 102 of the resulting structure was removed by dissolving it with a 0.5% aqueous hydrofluoric acid solution (by immersion at 25 °C for 1 minute) and then the structure was processed by contacting it with pure water, the processing fluids 1 to 18 (by immersion at 30 °C for 10 minutes) and pure water in that order, after which it was dried, resulting in a structure described in the Fig. Structure shown in 1(g) was provided.

[0033] The resulting structure exhibited a fine chimney-like pattern with cylindrical depressions of the metal (tungsten) (diameter: 125 nm, height: 1200 nm (aspect ratio: 9.6), distance between cylindrical depressions: 50 nm), and 70% or more of the pattern had not collapsed.

[0034] Pattern breakdown was investigated using an FE-SEM S-5500 (model number) manufactured by Hitachi High-Technologies Corporation, and the breakdown suppression percentage was a value obtained by calculating the proportion of the broken pattern within the total pattern. Cases where the breakdown suppression percentage was 50% or higher were rated as "passed." The processing fluids, processing methods, and the resulting breakdown suppression percentages in the examples are shown in Table 3. Comparative example 1

[0035] A structure that is in the Fig. The structure shown in 1(g) was obtained in the same way as in Example 1, except that the structure after removal of the silicon oxide 102 of the Fig.The structure shown in Figure 1(f) was processed by dissolving it with hydrofluoric acid using only pure water. 50% or more of the pattern of the resulting structure had collapsed, as shown in Figure 1(f). Fig. Example 1(h) is shown (which showed a breakdown suppression fraction of less than 50%). The processing fluid, the processing method, and the resulting breakdown suppression fraction in comparative example 1 are shown in Table 3. Comparative examples 2 to 14

[0036] Structures that are in the Fig. Examples 2 to 14, shown in 1(g), were obtained in the same way as in Example 1, except that the structures after removal of the silicon oxide 102 of the Fig.The structure shown in Figure 1(f) was processed by dissolving with hydrofluoric acid instead of processing fluid 1 with the comparison fluids 1 to 13 shown in Table 2. 50% or more of the pattern of resulting structures had collapsed, as shown in the Fig. 1(h) is shown. The comparison fluids, the processing methods and the obtained collapse suppression fractions in the comparison examples are shown in Table 3. Table 2 Name of the substance Comparison fluid 1 Isopropyl alcohol Comparison fluid 2 Diethylene glycol monomethyl ether Comparison fluid 3 Dimethylacetamide Comparison fluid 4 Ammoniumhalogenidperfluoralkylsulfonat * 1 Comparison fluid 5 Perfluoralkylcarbonatsalz * 2 Comparison fluid 6 Ethylene oxide adduct of 2,4,7,9-tetramethyl-5-decyne-4,7-diol * 3 Comparison fluid 7 2,4,7,9-Tetramethyl-5-decyn-4,7-diol * 4 Comparison fluid 8 Tridecylmethylammonium chloride (number of carbon atoms in the alkyl group: 12)* 5 Comparison fluid 9 Polyoxyethylenpolyoxypropylen-Blockpolymer * 6 Comparison fluid 10 1-Decyl-3-methylimidazolium chloride (number of carbon atoms in the alkyl group: 10) Comparison fluid 11 1-Dodecylpyridinium chloride (number of carbon atoms in the alkyl group: 12) Comparison fluid 12 1-Decyl-3-methylimidazolium chloride (number of carbon atoms in the alkyl group: 10) Comparison fluid 13 Dimethyldodecylamine oxide (number of carbon atoms in the alkyl group: 12) *1: “Fluorad FC-93”, trade name, manufactured by 3M Corporation, 0.01% aqueous solution *2: “Surfron S-111”, trade name, manufactured by AGC Seimi Chemical Co., Ltd., 0.01% aqueous solution *3: “Surfynol 420”, trade name, manufactured by Nisshin Chemical Industry Co., Ltd., 0.01% aqueous solution *4: “Surfynol 104”, trade name, manufactured by Nisshin Chemical Industry Co., Ltd., 0.01% aqueous solution *5: “Catiogen TML”, trade name, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., 0.01% aqueous solution *6: “Epan 420”, trade name, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., 0.01% aqueous solution Table 3 Processing procedures Breakdown suppression component * 1 Pass or fail Example 1 Pure water → Processing fluid 1 → Pure water → Drying 70% or more Passed Example 2 Pure water → Processing fluid 2 → Pure water → Drying 80% or more Passed Example 3 Pure water → Processing fluid 3 → Pure water → Drying 80% or more Passed Example 4 Pure water → Processing fluid 4 → Pure water → Drying 70% or more Passed Example 5 Pure water → Processing fluid 5 → Pure water → Drying 70% or more Passed Example 6 Pure water → Processing fluid 6 → Pure water → Drying 80% or more Passed Example 7 Pure water → Processing fluid 7 → Pure water → Drying 70% or more Passed Example 8** Pure water → Processing fluid 8 → Pure water → Drying 70% or more Passed Example 9** Pure water → Processing fluid 9 → Pure water → Drying 70% or more Passed Example 10** Pure water → Processing fluid 10 → Pure water → Drying 80% or more Passed Example 11** Pure water → Processing fluid 11 → Pure water → Drying 80% or more Passed Example 12** Pure water → Processing fluid 12 → Pure water → Drying 70% or more Passed Example 13** Pure water → Processing fluid 13 → Pure water → Drying 80% or more Passed Example 14 Pure water → Processing fluid 14 → Pure water → Drying 90% or more Passed Example 15 Pure water → Processing fluid 15 → Pure water → Drying 70% or more Passed Example 16 Pure water → Processing fluid 16 → Pure water → Drying 70% or more Passed Example 17 Pure water → Processing fluid 17 → Pure water → Drying 80% or more Passed Example 18 Pure water → Processing fluid 18 → Pure water → Drying 90% or more Passed Comparative example 1 Pure water → Drying less than 50% Failed Comparative example 2 Pure water → Reference liquid 1 → Pure water → Drying less than 50% Failed Comparative example 3 Pure water → Reference liquid 2 → pure water → Drying less than 50% Failed Comparative example 4 Pure water → Reference liquid 3 → pure water → Drying less than 50% Failed Comparative example 5 Pure water → Reference liquid 4 → pure water → Drying less than 50% Failed Comparative example 6 Pure water → Reference liquid 5 → Pure water → Drying less than 50% Failed Comparative example 7 Pure water → Reference liquid 6 → pure water → Drying less than 50% Failed Comparative example 8 Pure water → Reference liquid 7 → Pure water → Drying less than 50% Failed Comparative example 9 Pure water → Reference liquid 8 → pure water → Drying less than 50% Failed Comparative example 10 Pure water → Reference liquid 9 → Pure water → Drying less than 50% Failed Comparative example 11 Pure water → Reference liquid 10 → Pure water → Drying less than 50% Failed Comparative example 12 Pure water → Comparison liquid 11 → pure water → Drying less than 50% Failed Comparative example 13 Pure water → Reference liquid 12 → Pure water → Drying less than 50% Failed Comparative example 14 Pure water → Reference liquid 13 → Pure water → Drying less than 50% Failed *1: Collapse suppression rate = ((Number of non-collapsed cylindrical depressions) / (Total number of cylindrical depressions)) x 100 (%)** Reference example (%) Commercial applicability

[0037] The processing fluid can be advantageously used to suppress pattern breakdown in a fine metal structure, such as a semiconductor device and a micromachine (MEMS). Description of symbols 101 Photoresist 102 Silicon oxide 103 Silicon nitride 104 Silicon substrate 105 Circular opening 106 Cylindrical Hole 107 Metal (Tungsten) 108 Cylindrical depression made of metal (tungsten)

Claims

A process for producing a fine metal structure, comprising wet or dry etching, rinsing of impurities formed after dry or wet etching, subsequent rinsing with a processing fluid, rinsing with water after rinsing with the processing fluid, and drying after rinsing with water, wherein the processing fluid comprises at least one compound selected from the group consisting of: an imidazolium halide having an alkyl group containing 12, 14, or 16 carbon atoms; a pyridinium halide having an alkyl group containing 14 or 16 carbon atoms; a betaine compound having an alkyl group containing 12, 14, or 16 carbon atoms; and an amine oxide compound having an alkyl group containing 14, 16, or 18 carbon atoms, wherein the content of the at least one compound in the processing fluid is from 10 ppm to 10 wt%. Method for producing a fine metal structure according to claim 1, wherein the pattern of the fine metal structure contains tungsten. Method for producing a fine metal structure according to claim 1 or 2, wherein the fine metal structure is a semiconductor device or a micromachine. A method for producing a fine metal structure according to any one of claims 1 to 3, wherein the processing liquid comprises at least one compound selected from the group consisting of: an imidazolium halide comprising a dodecyl group, a tetradecyl group or a hexadecyl group; a pyridinium halide comprising a tetradecyl group or a hexadecyl group; a betaine compound comprising a dodecyl group, a tetradecyl group or a hexadecyl group; and an amine oxide compound comprising a tetradecyl group, a hexadecyl group or an octadecyl group. Method for producing a fine metal structure according to any one of claims 1 to 4, wherein the content of the at least one compound in the processing fluid is from 10 ppm to 5 wt%. Method for producing a fine metal structure according to any one of claims 1 to 5, wherein the content of the at least one compound in the processing fluid is from 10 ppm to 1000 ppm. Method for producing a fine metal structure according to any one of claims 1 to 6, wherein the processing liquid comprises dodecyldimethylaminoacetic acid betaine, palm oil fatty acid amide propyl betaine or both as a betaine compound. Method for producing a fine metal structure according to any one of claims 1 to 6, wherein the processing liquid comprises dimethyltetradecylamine oxide, dimethylhexadecylamine oxide, dimethyloctadecylamine oxide or a combination thereof as an amine oxide compound. Method for producing a fine metal structure according to any one of claims 1 to 6, wherein the processing liquid comprises an imidazolium halide comprising a C14 or C16 alkyl group. Method for producing a fine metal structure according to any one of claims 1 to 6, wherein the processing liquid comprises an imidazolium halide comprising a C16 alkyl group. Method for producing a fine metal structure according to any one of claims 1 to 6, wherein the processing liquid comprises a pyridinium halide comprising a C16 alkyl group. Method for producing a fine metal structure according to any one of claims 1 to 6, wherein the processing liquid comprises an amine oxide compound comprising a C16 or C18 alkyl group. Method for producing a fine metal structure according to any one of claims 1 to 12, wherein the processing fluid further comprises water. A method for producing a fine metal structure according to any one of claims 1 to 13, comprising in the following order: wet etching or dry etching of silicon oxide to create etched areas, filling the etched areas and producing a fine metal structure, wherein the metal structure contains tungsten, a first rinsing of the fine metal structure with water after producing the fine metal structure, a rinsing of the fine metal structure with the processing fluid after the first rinsing, a second rinsing of the fine metal structure with water after rinsing with the processing fluid, and drying after the second rinsing with water.

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