Method for regenerating etchant

Abstract

This invention provides a method for regenerating etching solutions. This method regenerates not only conventional etching solutions but also high-performance etching solutions incorporating silicon dioxide precipitation inhibitors. The method specifically regenerates etching solutions from inorganic acid-based etching solutions used or used in semiconductor etching processes using diffusion dialysis. The method includes an extraction step whereby the etching solution containing a dialysis aid is contacted with water through an anion exchange membrane to extract the inorganic acids contained in the etching solution into the water.

Description

Method for regenerating etching solution The present invention relates to a method for regenerating an etching solution, which regenerates an inorganic acid-based etching solution used in or after semiconductor etching by a diffusion dialysis method. With the high integration and high capacity of semiconductor circuits, higher-precision etching techniques are required. In particular, in the manufacturing process of semiconductors having a silicon oxide film and a silicon nitride film as a sacrificial layer (such as 2D NAND, 3D NAND, CMOS, DRAM, 3DRAM, logic IC, etc.), it is necessary to precisely remove only the silicon nitride film. Therefore, in order to achieve high etching selectivity, an etching inhibitor is added to the etching solution to inhibit the etching of silicon oxide. For example, the etching solution described in Patent Document 1 is used in the manufacturing process of three-dimensional semiconductors, and is a composition obtained by mixing a solution containing silicon dioxide and an alkali, phosphoric acid, and water. According to Patent Document 1, it is considered that by using such an etching solution, the etching of the silicon oxide film is inhibited and the etching selectivity of the silicon nitride film is improved (refer to paragraph 0013 of the specification of Patent Document 1). Incidentally, the treatment cost of the etching solution at the time of disposal is very high, so it is desired to reuse it. However, the etching solution (fatigue solution) used in semiconductor etching treatment contains many Si compounds from the semiconductor. Therefore, in order to reuse the used etching solution, the Si compounds must be removed from the etching solution. As a method for removing the Si compounds contained in the etching solution, for example, there is a removal method using a filter described in Patent Document 2. According to Patent Document 2, by using a filter medium having a high removal rate of Si compounds as a filter, regeneration of the etching solution suitable for an industrial process can be performed (refer to paragraph 0018 of the specification of Patent Document 2). [Prior art documents] [Patent documents] [Patent Document 1] Japanese Patent Application Laid-Open No. 2020-96160 [Patent Document 2] Japanese Patent No. 4944558 [Problems to be solved by the invention] However, the etching solution of Patent Document 1 originally contains silicon dioxide (silicic acid) as an additive. Therefore, if the etching treatment of silicon nitride is performed, the concentration of silicic acid in the solution becomes higher. As a result, silicon dioxide becomes fine crystals in the solution and is likely to precipitate. Therefore, when regenerating the etching solution of Patent Document 1, if a filter as in Patent Document 2 is used, there is a concern that the filter will be blocked in a short time. In addition, in recent years, etching liquids used have been designed to suppress the precipitation of Si compounds dissolved in the etching liquid in the form of silicon dioxide on the semiconductor substrate in response to the demand for higher functionality from users. In addition, in this specification, in order to distinguish from conventional etching liquids, an etching liquid in which the precipitation of such silicon dioxide is suppressed is referred to as a "high-functional etching liquid". Since the high-functional etching liquid contains a precipitation inhibitor that suppresses the precipitation of silicon dioxide, the Si compounds exist in a state dissolved in the liquid. Therefore, when regenerating the high-functional etching liquid, the Si compounds in the liquid cannot be removed at all by the removal method using a filter as in Patent Document 2. The present invention has been completed in view of the above problems, and an object thereof is to provide a method for regenerating an etching liquid, which can regenerate not only a conventional etching liquid but also a high-functional etching liquid in which a precipitation inhibitor of silicon dioxide is blended in the etching liquid when regenerating an etching liquid (fatigue liquid) used in the etching process of a semiconductor. [Means for Solving the Problems] The etching liquid regeneration method related to the present invention for solving the above problems is characterized in that it is an etching liquid regeneration method for regenerating an inorganic acid-based etching liquid used in or after the etching of a semiconductor by a diffusion dialysis method, and includes: an extraction step of extracting an inorganic acid contained in the etching liquid into water by bringing the etching liquid containing a dialysis aid into contact with water through an anion exchange membrane. According to the etching liquid regeneration method of this configuration, when regenerating an inorganic acid-based etching liquid used in or after the etching of a semiconductor, instead of performing the conventional filtration using a filter, a diffusion dialysis method using an anion exchange membrane is adopted. The diffusion dialysis method is a method of extracting an inorganic acid contained in the etching liquid into water by bringing the etching liquid into contact with water through an anion exchange membrane. Here, since a dialysis aid is contained in the etching liquid, clogging does not occur during the diffusion dialysis process, and the inorganic acid can be recovered. Therefore, not only a conventional etching liquid but also a high-functional etching liquid in which a precipitation inhibitor that suppresses the precipitation of silicon dioxide is blended in the etching liquid can be regenerated. In the etching liquid regeneration method related to the present invention, it is preferable to have an addition step of adding a dialysis aid to the etching liquid before the extraction step to prepare an etching liquid containing the dialysis aid. According to the etching liquid regeneration method of this configuration, when regenerating the etching liquid by the diffusion dialysis method, a dialysis aid is added to the etching liquid (used etching liquid) before the extraction step (addition step). Thereby, the dialysis property of the anion exchange membrane can be sufficiently maintained, and the inorganic acid contained in the etching liquid can be efficiently extracted into water. As a result, of course, the used etching liquid (fatigue liquid) can be made into an etching liquid again and regenerated, and it can also be regenerated into a state that can be used for various purposes other than the etching liquid. In the method for regenerating an etching solution according to the present invention, it is preferable to include a preparation step of adding all or a part of a dialysis aid to the etching solution before etching the semiconductor to prepare an etching solution containing the dialysis aid. In the method for regenerating an etching solution according to this configuration, when regenerating the etching solution by the diffusion dialysis method, before etching the semiconductor, all or a part of a dialysis aid is added to the etching solution (unused etching solution) (preparation step). Thereby, the dialysis property of the anion exchange membrane can be sufficiently maintained, and the inorganic acid contained in the etching solution can be efficiently extracted into water. As a result, of course, the used etching solution (fatigue solution) can be made into an etching solution again for regeneration, and it can also be regenerated into a state that can be used for various purposes other than the etching solution. In addition, when a part of the dialysis aid is added to the etching solution (unused etching solution), the remaining part of the dialysis aid can be added to the etching solution (used etching solution) before the extraction step. In the method for regenerating an etching solution according to the present invention, it is preferable that the dialysis aid is a heteroatom-containing compound. In the method for regenerating an etching solution according to this configuration, by using a heteroatom-containing compound as the dialysis aid, the dialysis efficiency is improved. As a result, the inorganic acid contained in the etching solution can be efficiently extracted into water. In the method for regenerating an etching solution according to the present invention, it is preferable that the heteroatom-containing compound is a silicon atom-containing compound, a nitrogen atom-containing compound, and / or a phosphorus atom-containing compound. In the method for regenerating an etching solution according to this configuration, by using a silicon atom-containing compound, a nitrogen atom-containing compound, and / or a phosphorus atom-containing compound as the dialysis aid, the dialysis efficiency is further improved. As a result, the inorganic acid contained in the etching solution can be more efficiently extracted into water. In the method for regenerating an etching solution according to the present invention, it is preferable that the silicon atom-containing compound is a silane compound having 3 or less alkoxy groups, hydroxyl groups, and / or functional groups that are precursors of hydroxyl groups in the molecular structure, and / or a silane compound having 4 or more alkoxy groups, hydroxyl groups, and / or functional groups that are precursors of hydroxyl groups in the molecular structure, and / or a halogen atom-containing silane compound. In the method for regenerating an etching solution according to this configuration, by using the above silane compound as the dialysis aid, particularly excellent dialysis efficiency can be achieved. In the method for regenerating an etching solution according to the present invention, it is preferable that the nitrogen atom-containing compound is hydrazides and / or ammonium compounds. In the method for regenerating an etching solution according to this configuration, by using hydrazides and / or ammonium compounds as the dialysis aid, particularly excellent dialysis efficiency can be achieved. In the method for regenerating an etching solution according to the present invention, the phosphorus atom-containing compound is preferably a phosphonic acid compound. According to the method for regenerating an etching solution of this configuration, by using a phosphonic acid compound as a dialysis aid, particularly excellent dialysis efficiency can be achieved. In the method for regenerating an etching solution according to the present invention, the inorganic acid is preferably phosphoric acid. According to the method for regenerating an etching solution of this configuration, it is suitable for regenerating a semiconductor etching solution based on phosphoric acid as an inorganic acid. In the method for regenerating an etching solution according to the present invention, the etching solution preferably contains Si from the semiconductor at a concentration equal to or higher than a predetermined concentration. According to the method for regenerating an etching solution of this configuration, any etching solution containing Si from the semiconductor at a concentration equal to or higher than a predetermined concentration can be regenerated, so it is useful. In the method for regenerating an etching solution according to the present invention, the etching solution is preferably a spent solution used in the etching of the semiconductor. According to the method for regenerating an etching solution of this configuration, especially when applied to a spent solution used in semiconductor etching, it will be a method with great advantages for regeneration. In the method for regenerating an etching solution according to the present invention, the extraction step is preferably performed by countercurrent contact of the etching solution and the water through an anion exchange membrane. According to the method for regenerating an etching solution of this configuration, by performing countercurrent contact, the inorganic acid contained in the etching solution can be efficiently extracted into the water. In the method for regenerating an etching solution according to the present invention, the semiconductor is preferably a semiconductor having a silicon nitride film as a sacrificial layer. According to the method for regenerating an etching solution of this configuration, it is suitable for regenerating an etching solution (spent solution) with a high Si concentration from silicon nitride. An embodiment of the method for regenerating an etching solution according to the present invention will be described. However, the present invention is not intended to be limited by the following embodiments. [Etching Solution] In the method for regenerating an etching solution according to the present invention, the etching solution to be regenerated is an etching solution used in or after the etching of a semiconductor. Here, examples of the etching solution used in the etching of a semiconductor include an etching solution in a state where it is not unused but still usable. Examples of the etching solution after being used in the etching of a semiconductor include a fully used etching solution (so-called spent solution). The method for regenerating an etching solution according to the present invention can be applied not only to conventional etching solutions but also to the regeneration of a highly functional etching solution (high-functional etching solution) that suppresses the precipitation of silicon dioxide. The etching solution (treatment solution) provided to the regeneration method of the etching solution related to the present invention is based on an inorganic acid and contains a dialysis aid. The dialysis aid functions to improve the dialysis efficiency or inhibit the increase in dialysis resistance during the diffusion dialysis of the etching solution using an anion exchange membrane. The inorganic acid and dialysis aid contained in the etching solution are described below. <Inorganic Acid> Examples of the inorganic acid include phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid, and mixed acids of these inorganic acids. Among these inorganic acids, phosphoric acid is preferred. When phosphoric acid is used after dilution, it can be in the form of an aqueous solution, and its concentration is preferably 50 to 100% by weight (wt%), more preferably 70 to 95% by weight, and even more preferably 85 to 95% by weight. In addition, as long as the phosphoric acid is adjusted to the above concentration when the etching solution is used, for example, when using a stock solution containing a dilute phosphoric acid aqueous solution, it can be concentrated before use, when using a stock solution containing phosphoric acid with a concentration exceeding 100% by weight (concentrated phosphoric acid), it can be diluted with water before use, or when using anhydrous phosphoric acid (P 2 O 5 ) and dissolving it in water before use, the appropriate concentration can be adjusted. <Dialysis Aid> Examples of the dialysis aid include heteroatom-containing compounds. Examples of the heteroatom-containing compounds include Si atom-containing compounds, N atom-containing compounds, and / or P atom-containing compounds. In addition, the Si atom-containing compound is a compound that can also function as an etching inhibitor for suppressing the etching of silicon oxide, and the N atom-containing compound and the P atom-containing compound are compounds that can also function as precipitation inhibitors for suppressing the precipitation of silicon dioxide on the surface of silicon oxide. [Si Atom-Containing Compounds] The Si atom-containing compounds mainly include silane compounds having 3 or fewer alkoxy groups, hydroxyl groups, and / or functional groups that are precursors of hydroxyl groups in the molecular structure (referred to as "first silane compounds"), and / or silane compounds having 4 or more alkoxy groups, hydroxyl groups, and / or functional groups that are precursors of hydroxyl groups in the molecular structure (referred to as "second silane compounds"). Among the first silane compounds and the second silane compounds, the silane compounds having hydroxyl groups only need to be silane compounds that can be converted into silane compounds having hydroxyl groups in the final solution. The content of the Si atom-containing compound in the etching solution is preferably 0.5 to 20% by weight, more preferably 1 to 20% by weight, and even more preferably 1 to 6% by weight for the first silane compound. For the second silane compound, it is preferably 0.01 to 5% by weight, more preferably 0.01 to 1% by weight, and even more preferably 0.09 to 0.6% by weight. Examples of the Si atom-containing compound are given below. Examples of the first silane compound include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, dimethoxydiphenylsilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, 1,6-bis(trimethoxysilyl)hexane, vinyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-4-aminobutyltrimethoxysilane, N-2-(aminoethyl)-5-aminopentyltrimethoxysilane, N-2-(aminoethyl)-6-aminohexyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane, and hydrochlorides of the above amino silanes, tris(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-trimethoxysilylpropyl succinic anhydride, and hydrolyzates of the above alkoxysilanes. Among these first silane compounds, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and hydrolyzates of these alkoxysilanes are preferred. The above first silane compounds can be used alone or in a state where two or more are mixed. Generally, the second silane compound has a chemical structure represented by the following formula (1). Here, R in formula (1) 1 ~R 6As substituents, at least 4 of these substituents are at least one specific substituent selected from the group consisting of alkoxy groups, hydroxyl groups, and chlorine, and the substituents other than the specific substituent are at least one substituent selected from the group consisting of alkyl groups, aromatic groups, carbonyl groups, carboxyl groups, amino groups, ethylenediamine groups, and derivatives or composite groups of these substituents. X in formula (1) is "O" (oxygen atom) or "-" (single bond). n in formula (1) is an integer from 0 to 3. Thus, in addition to compounds having alkoxy groups (siloxane compounds or disilane compounds, the same applies hereinafter) and compounds having hydroxyl groups, compounds having chlorine can also be used as the second silane compound. In addition, the compounds having alkoxy groups and the compounds having chlorine are hydrolyzed and ultimately become compounds having hydroxyl groups. Specific examples of the second silane compound include the following chemical structural formula (1): 1,3-dimethyltetramethoxydisiloxane represented by, the following chemical structural formula (2): The siloxane compound represented by, the following chemical structural formula (3): The siloxane compound represented by, the following chemical structural formula (4): Hexamethoxydisiloxane, tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, hexamethyldisilane, hexaethyldisilane, hexabutyldisilane, hexamethoxydisiloxane, hexaethoxydisiloxane, hexabutyldisiloxane, 1,3-dimethyltetraethoxydisiloxane, 1,3-dimethyltetrabutoxydisiloxane, 1,3-diethyltetramethoxydisiloxane, 1,3-diethyltetraethoxydisiloxane, 1,3-diethyltetrabutoxydisiloxane, 1,3-divinyltetramethoxydisiloxane, 1,3-divinyltetraethoxydisiloxane, 1,3-divinyltetrabutoxydisiloxane, 1,3-bis(3-aminopropyl)tetramethoxydisiloxane, silicon tetrachloride, hexachlorodisilane, hexachlorodisiloxane, 1,3-dimethyltetrachlorodisiloxane, 1,3-diethyltetrachlorodisiloxane, 1,3-dibutyltetrachlorodisiloxane, etc. Incidentally, commercially available siloxane compounds include silane coupling agents "X-12-1098", "X-12-1135", "KBP-64", and "KBP-90" manufactured by Shin-Etsu Chemical Co., Ltd. The above-mentioned second silane compound can be used alone or in a state where two or more are mixed. Compounds containing Si atoms, in addition to the above-mentioned first silane compound and second silane compound, also include silane compounds containing halogen atoms. Examples of silane compounds containing halogen atoms include hexafluorosilicic acid or its salts. [Compound Containing N Atom] Compounds containing N atoms include hydrazine compounds, pyrazoles, triazoles, hydrazides, ammonium compounds, compounds having an imidazole skeleton, compounds having a pyrrolidine skeleton, compounds having a piperidine skeleton, compounds having a morpholine skeleton, compounds having a pyridine skeleton, compounds having a quaternary ammonium skeleton, compounds having a pyrimidine skeleton, compounds having a purine skeleton, compounds having a urea skeleton, etc. Hydrazides and ammonium compounds are suitable for use. The above-mentioned compounds and types can be used alone or in a state where two or more are mixed. If two or more different compounds containing N atoms are used, it will be very useful not only from the perspective of the performance of the etching process but also from the perspectives of extending the life of the etching solution or reducing costs. The content of the compound containing N atoms in the etching solution is preferably 0.1 to 1% by weight, more preferably 0.3 to 0.4% by weight. The following is an illustration of the compound containing N atoms. [Hydrazine Compounds] Hydrazine compounds include hydrazine, butyl hydrazine, isopropyl hydrazine, benzyl hydrazine, N,N-dimethyl hydrazine, 1,2-diacetyl hydrazine, phenyl hydrazine, N,N-diformyl hydrazine, hydrazine sulfate, monohydrochloride hydrazine, dihydrochloride hydrazine, butyl hydrazine hydrochloride, hydrazine carbonate, and monohydrobromide hydrazine, etc. The above-mentioned hydrazine compounds can be used alone or in a state where two or more are mixed. [Pyrazoles] Pyrazoles include 3,5-dimethylpyrazole and 3-methyl-5-pyrazolone, etc. The above-mentioned pyrazoles can be used alone or in a state where two or more are mixed. [Triazoles] Triazoles include 4-amino-1,2,4-triazole, 1,2,4-triazole, 1,2,3-triazole, 1-hydroxybenzotriazole, and 3-mercapto-1,2,4-triazole, etc. The above-mentioned triazoles can be used alone or in a state where two or more are mixed. [Hydrazides] Hydrazides include propionyl hydrazide, lauroyl hydrazide, salicyloyl hydrazide, formyl hydrazide, acetyl hydrazide, chloroacetyl hydrazide, p-hydroxybenzoic acid hydrazide, naphthoic acid hydrazide, 3-hydroxy-2-naphthoic acid hydrazide, benzoyl hydrazide, carbohydrazide, oxalic dihydrazide, malonic dihydrazide, succinic dihydrazide, succinic 2,2-dimethyl hydrazide, glutaric dihydrazide, adipic dihydrazide, azelaic dihydrazide, sebacic dihydrazide, dodecanedioic dihydrazide, maleic dihydrazide, fumaric dihydrazide, tartaric dihydrazide, malic dihydrazide, diglycolic dihydrazide, isophthalic dihydrazide, terephthalic dihydrazide, 2,6-naphthalenedicarboxylic dihydrazide, 2,6-naphthalic acid dihydrazide, citric trihydrazide, pyromellitic trihydrazide, 1,2,4-benzenetricarboxylic trihydrazide, nitrilotriacetic acid trihydrazide, 1,3,5-cyclohexanetricarboxylic trihydrazide, ethylenediaminetetraacetic acid tetrahydrazide, and 1,4,5,8-naphthalenetetracarboxylic acid tetrahydrazide, etc. Among these hydrazides, adipic dihydrazide, succinic dihydrazide, chloroacetyl hydrazide, succinic 2,2-dimethyl hydrazide, and azelaic dihydrazide are preferred. The above hydrazides can be used alone or in a state of mixing two or more of them. [Ammonium Compounds] Ammonium compounds include ammonium phosphate, ammonium sulfate, ammonium nitrate, ammonium chloride, etc., and ammonium phosphate is preferred. The above ammonium compounds can be used alone or in a state of mixing two or more of them. [Compounds with Imidazole Skeleton] Compounds with an imidazole skeleton include compounds such as imidazole, imidazole formic acid, imidoylurea, bis(hydroxymethyl) imidazolidinyl urea, 3-(2-oxoimidazolidin-1-yl) benzoic acid, and imidazole hydrochloride, etc., and imidazolium salts such as 1-ethyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride, 1,3-dimethylimidazolium methyl sulfate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-octylimidazolium tetrafluoroborate, 1,3-dimethylimidazolium dimethyl phosphate, 1-ethyl-3-methylimidazolium tetrafluoroborate, and 1-ethyl-3-methylimidazolium phosphate, etc. The above compounds with an imidazole skeleton can be used alone or in a state of mixing two or more of them. [Compounds with a pyrrolidine skeleton] Compounds with a pyrrolidine skeleton include compounds such as pyrrolidine, 2-pyrrolidone, N-methylpyrrolidone, N-vinyl-2-pyrrolidone, pyroglutamic acid, and piracetam, as well as pyrrolidinium salts such as 1-ethyl-1-methylpyrrolidinium chloride, 1-butyl-1-methylpyrrolidinium chloride, 1-ethyl-1-methylpyrrolidinium acetate, 1-ethyl-1-methylpyrrolidinium tetrafluoroborate, 1-butyl-1-methylpyrrolidinium tetrafluoroborate, 1-ethyl-1-methylpyrrolidinium hexafluorophosphate, and 1-butyl-1-methylpyrrolidinium hexafluorophosphate. The above-mentioned compounds with a pyrrolidine skeleton can be used alone or in a state where two or more are mixed. [Compounds with a piperidine skeleton] Compounds with a piperidine skeleton include compounds such as piperidine, ethyl piperidine-4-carboxylate, piperidin-2-ylacetic acid, and methyl piperidine-4-carboxamide, as well as piperidinium salts such as (piperidinium-1-ylmethyl) trifluoroborate, 1-butyl-1-methylpiperidinium bromide, and 1-butyl-1-methylpiperidinium bisimide. The above-mentioned compounds with a piperidine skeleton can be used alone or in a state where two or more are mixed. [Compounds with a morpholine skeleton] Compounds with a morpholine skeleton include compounds such as morpholine, morpholin-2-ylmethanol, morpholin-3-one, morpholine-4-carbothioamide, morpholin-4-ylacetic acid, and ethyl morpholin-4-ylacetate, as well as morpholinium salts such as 4-ethyl-4-methylmorpholinium bromide and 4-(2-ethoxyethyl)-4-methylmorpholinium bisimide. The above-mentioned compounds with a morpholine skeleton can be used alone or in a state where two or more are mixed. [Compounds with a pyridine skeleton] Compounds with a pyridine skeleton include compounds such as pyridine, N,N-dimethyl-4-aminopyridine, bipyridine, 2,6-dimethylpyridine, and pyridinium p-toluenesulfonate, as well as pyridinium salts such as 1-butyl-3-methylpyridinium chloride, 1-butylpyridinium tetrafluoroborate, and 1-butylpyridinium hexafluorophosphate. The above-mentioned compounds with a pyridine skeleton can be used alone or in a state where two or more are mixed. [Compounds with a quaternary ammonium skeleton] Compounds with a quaternary ammonium skeleton include tetramethylammonium chloride, tetrabutylammonium chloride, tetramethylammonium bromide, tetramethylammonium hydroxide, tetramethylammonium iodide, tetrabutylammonium bromide, tetrabutylammonium hydrogen sulfate, tetramethylammonium hexafluorophosphate, tetrabutylammonium hexafluorophosphate, and acetylcholine. The above-mentioned compounds with a quaternary ammonium skeleton can be used alone or in a state where two or more are mixed. [Compounds with a pyrimidine skeleton] Compounds with a pyrimidine skeleton include thymine, cytosine, uracil, and nucleosides, ribonucleosides, and deoxyribonucleosides of the above compounds. The above compounds with a pyrimidine skeleton can be used alone or in a state where two or more are mixed. [Compounds with a purine skeleton] Compounds with a purine skeleton include purine, adenine, guanine, uric acid, caffeine, hypoxanthine, xanthine, theophylline, theobromine, isoguanine, and nucleosides, ribonucleosides, and deoxyribonucleosides of the above compounds. The above compounds with a purine skeleton can be used alone or in a state where two or more are mixed. [Compounds with a urea skeleton] Compounds with a urea skeleton include urea, hydroxyurea, N,N - diethylthiourea, N,N - dibutylthiourea, biurea, biuret, N - formamidothiourea, etc. The above compounds with a urea skeleton can be used alone or in a state where two or more are mixed. [Compounds containing a P atom] Compounds containing a P atom include phosphonic acid compounds. Phosphonic acid compounds include compounds such as phosphonic acid, diphenyl phosphonate, butyl phosphonate, dipentyl phosphonate, phosphorous acid, hypophosphorous acid, and ammonium phosphate, as well as phosphonium salts such as tetrabutylphosphonium hexafluorophosphate, tetrabutylphosphonium bisimide, and tetrabutylphosphonium bromide. In addition, ammonium phosphate compounds are compounds containing a P atom but also contain an N atom. The above phosphonic acid compounds can be used alone or in a state where two or more are mixed. [Preparation of the etching solution before regeneration treatment] The etching solution for regeneration treatment can be prepared by adding a dialysis aid. The dialysis aid can be added directly to the etching solution or added to the etching solution in a state where the dialysis aid is dissolved or suspended in a solvent. The timing of adding the dialysis aid to the etching solution is generally added to the exhausted solution after use in semiconductor etching, but it can also be added to a brand - new etching solution before use in semiconductor etching in advance. Adding the dialysis aid to the etching solution can be carried out at room temperature or simultaneously while heating the etching solution. <Solvent> Solvents that dissolve or suspend the dialysis aid include alcohols such as water, methanol, ethanol, 2-propanol, butanol, octanol, benzyl alcohol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 2,2,2-trifluoroethanol, ethers such as diethyl ether, diisopropyl ether, dibutyl ether, cyclopentyl methyl ether (CPME), tetrahydrofuran (THF), 2-methyltetrahydrofuran, 1,4-dioxane, dimethoxyethane, carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, 4-fluoroethylene carbonate, esters such as methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, γ-lactone, nitriles such as acetonitrile, propionitrile, valeronitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, benzonitrile, amides such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), ureas such as dimethyl sulfoxide (DMSO), hexamethylphosphoric triamide (HMPA), N,N,N',N'-tetramethylurea (TMU), N,N'-dimethylpropyleneurea (DMPU), and ionic liquids such as imidazolinium salts, pyrrolidinium salts, piperidinium salts, pyridinium salts, morpholinium salts, phosphonium salts, quaternary ammonium salts, and sulfonium salts. Regarding ionic liquids, examples of cations include imidazolinium skeletons, pyrrolidinium skeletons, piperidinium skeletons, morpholinium skeletons, pyridinium skeletons, quaternary phosphonium skeletons, quaternary ammonium skeletons, and sulfonium skeletons, and examples of anions include Br ‾ 、BF 4 ‾ 、PF 6 ‾ 、(CN) 2 N ‾ 、Cl ‾ 、I ‾ 、(CF 3 SO 2 )N ‾ 、(F 2 SO 2 )N ‾ 、CH 3 COO ‾ , HSO 4 ‾ , (CH 3 ) 2 PO 4 ‾ , CF 3 COO ‾ , CH 3 SO 3 ‾ , CF 3 SO 3 ‾ and SCN ‾ etc. The above solvents can be used alone or in a state where two or more are mixed. <Surfactant> When dissolving or suspending the dialysis aid in a solvent, a surfactant can also be used in combination. As the surfactant, any one of a cationic surfactant, an anionic surfactant, an amphoteric surfactant, and a nonionic surfactant can be used, and these surfactants can also be used in combination. [Regeneration of etching solution] When an etching solution is used in semiconductor etching, the Si component from silicon nitride accumulates slowly in the etching solution. If the Si concentration exceeds a predetermined concentration, it becomes unusable. On the other hand, high-performance etching solutions also contain Si components from silane coupling agents, etc. However, high-performance etching solutions can be used even when the concentration of Si from silicon nitride in the solution reaches a significantly higher concentration than that of conventional etching solutions. The reason is that silane coupling agents, etc., maintain a stable structure even at an arbitrarily high temperature in the etching solution, and the Si components from silane coupling agents, etc., precipitate in the form of silicon dioxide, etc., which has nothing to do with the degradation of the etching solution performance. However, in high-performance etching solutions, if the Si concentration from silicon nitride in the solution becomes too high, the Si components will aggregate, etc., and become microcrystals of silicon dioxide, which are likely to precipitate in the solution. Thus, in the present invention, the used etching solution (fatigue solution) is regenerated to make an etching solution (including high-performance etching solutions) again, or can be reused as various other products. The following describes related embodiments of the method for regenerating an etching solution of the present invention. In addition, in the following embodiments, phosphoric acid (H 3 PO 4 ) is used as the inorganic acid that forms the base of the etching solution. In addition, regarding the unit (%) of the concentration of phosphoric acid used in the etching solution, it is defined as weight %. Regarding the unit (ppm) of the Si concentration from silicon nitride in the etching solution, it is defined as the unit (mg / kg) based on weight. <Regeneration Device> First, a regeneration device for implementing the method for regenerating an etching solution of the present invention will be described. FIG. 1 is a schematic configuration diagram of a regeneration device 100 for regenerating an etching solution. FIG. 1(a) is an overall configuration diagram of the regeneration device 100, and FIG. 1(b) is a partially enlarged view of the regeneration device 100 surrounded by a dashed ellipse A in FIG. 1(a). The regeneration device 100 is a device for regenerating an etching solution used in or after semiconductor etching. The main configuration of the regeneration device 100 includes: a stock solution storage tank 10 for storing the used etching solution, a water storage tank 20 for storing water, an auxiliary agent storage tank 30 for storing a dialysis aid, a diffusion dialysis device 40 for regenerating the etching solution, a treatment solution storage tank 50 for storing the treatment solution (hereinafter also referred to as "recovered acid") generated by the diffusion dialysis device 40, and a discharge solution storage tank 60 for storing the discharge solution (hereinafter also referred to as "deacidified solution") discharged from the diffusion dialysis device 40. In addition, all the dialysis aids can be added to a brand-new etching solution in advance before being used in semiconductor etching. In this case, the auxiliary agent storage tank 30 can be omitted. Additionally, a part of the dialysis aid can be added to a brand-new etching solution in advance before being used in semiconductor etching. In this case, only the remaining part of the dialysis aid needs to be stored in the auxiliary agent storage tank 30. The stock solution storage tank 10 stores a phosphoric acid-based etching solution (fatigue solution) used in the etching of a semiconductor (such as 2D NAND, 3D NAND, CMOS, DRAM, 3DRAM, logic IC, etc.) having a silicon nitride film as a sacrificial layer. Since this etching solution has been used, it contains Si from silicon nitride at a concentration above a predetermined concentration. The concentration of Si from silicon nitride (predetermined concentration) is usually 10 ppm or more, for example, predicted to be in the range of about 50 to 2000 ppm, and there may also be cases where it reaches 3000 ppm. The water storage tank 20 stores the water used for regenerating the etching solution. Since this water will become the medium for extracting phosphoric acid from the etching solution, pure water is preferred. An aqueous solution in which a dialysis aid is dissolved in water is stored in the auxiliary agent storage tank 30. As the dialysis aid, any of the various heteroatom-containing compounds described above can be used. The dialysis aid is added to the stock solution storage tank 10 by the auxiliary agent addition pump 31. In addition, when the etching solution already contains a sufficient amount of the heteroatom-containing compound, it is regarded that the dialysis aid has been added, and the addition amount of the dialysis aid to the stock solution storage tank 10 can be reduced or the addition of the dialysis aid to the stock solution storage tank 10 can be omitted. The diffusion dialysis device 40 mainly includes a plurality of anion exchange membranes 42. Both ends of the plurality of anion exchange membranes 42 are clamped by the frame 41. The number of the anion exchange membranes 42 can be appropriately set. Each anion exchange membrane 42 is arranged in parallel with a certain interval through a spacer (not shown). Thereby, a space 43 is formed in parallel between adjacent anion exchange membranes 42. In each space 43, the etching solution transported from the stock solution storage tank 10 by the stock solution pump 11 or the water transported from the water storage tank 20 by the water pump 21 flows alternately in opposite directions. Thereby, the etching solution and water come into countercurrent contact through the anion exchange membrane 42. In addition, before the etching solution is introduced into the diffusion dialysis device 40, it can pass through the filtration device 12 as necessary. Thereby, insoluble components present in the etching solution can be removed, and thus blockage of the anion exchange membrane 42 during the diffusion dialysis process can be surely prevented. The processed liquid storage tank 50 stores the recovered acid (aqueous phosphoric acid solution) after being processed by the diffusion dialysis device 40. The aqueous phosphoric acid solution is pumped out by the processed liquid pump 51 and reused after passing through the concentration device 52 as necessary. The discharge liquid storage tank 60 stores the discharge liquid (deacidified liquid after extracting phosphoric acid from the etching solution) generated by the diffusion dialysis device 40. After the discharge liquid is pumped out by the discharge liquid pump 61, it can be subjected to neutralization treatment or desiliconization treatment, etc. in a discharge liquid treatment device (not shown) as necessary. <Regeneration Method> FIG. 2 is a flowchart showing a regeneration method of the etching solution related to the present invention. In the regeneration method of the etching solution, as an essential step, it includes an extraction step of extracting an inorganic acid contained in the etching solution containing a dialysis aid into water. In addition, as a suitable step, it includes an addition step of adding a dialysis aid to the etching solution before the extraction step. Furthermore, as an additional step to be carried out as necessary, it includes a filtration step before the extraction step and a concentration step after the extraction step. In addition, different from each step shown in FIG. 2, there may also be a case where a preparation step of adding a dialysis aid to the etching solution before etching the semiconductor is carried out. In the following embodiments, the regeneration method of the etching solution will be described by taking a case where the addition step and the extraction step are carried out. For example, when the phosphoric acid concentration is H 3 PO 4When regenerating 80 to 100% of the used etching solution (fatigue solution), a dialysis aid (S1; addition step) is added to the etching solution. It is preferable to add the dialysis aid in the form of an aqueous solution dissolved in water, but the solid (powder) dialysis aid can also be directly added to the etching solution. When adding the powdered dialysis aid to the etching solution, for example, a screw feeder can be used instead of the aid storage tank 30 and the aid addition pump 31 shown in Fig. 1(a). The etching solution added with the dialysis aid is brought into contact with water through an anion exchange membrane, and the phosphoric acid contained in the etching solution is extracted into the water (S3; extraction step). Here, the extraction step will be described in more detail. In the used etching solution, Si from silicon nitride is usually contained at a concentration above a certain level. Generally, if Si compounds accumulate in the etching solution (if the Si concentration increases), as described above, the Si compounds will become fine silica crystals and easily precipitate. However, in the present invention, since a dialysis aid is added to the etching solution, the Si compounds remain stable in the solution, and the precipitation of silica is suppressed. On the other hand, in the conventional filtration using a filter, the Si component in the solution cannot be removed even from the etching solution in which the precipitation of silica is suppressed. Therefore, in the present invention, the diffusion dialysis method using an anion exchange membrane is adopted. The diffusion dialysis method is a method of moving the phosphoric acid contained in the etching solution into the water by bringing the etching solution into contact with water through an anion exchange membrane. In the present invention, when extracting phosphoric acid by the diffusion dialysis method, the etching solution and water are brought into countercurrent contact through the anion exchange membrane. In the example shown in Fig. 1(a), among the plurality of spaces 43 formed in parallel between the adjacent anion exchange membranes 42, starting from the left side of the figure, the etching solution is allowed to flow under the anion exchange membrane 42 in the even-numbered spaces 43, and pure water is allowed to pass above the anion exchange membrane 42 in the odd-numbered spaces 43. In the etching solution, as shown in Fig. 1(b), it contains phosphate ions (PO 4 3- ) and silicon-containing cations (Si + ). In addition, since silicon is an element that is difficult to ionize alone, it is considered that it actually exists in the form of complex ions, etc., but in this specification and Fig. 1(b), for convenience, it is represented as silicon ions (Si +) will be used for explanation. If the etching solution and water are brought into countercurrent contact through an anion exchange membrane, the phosphate ions in the etching solution can move through the anion exchange membrane 42 into the water, while the silicon ions cannot pass through the anion exchange membrane 42 and remain in the etching solution. A dialysis aid is added to the etching solution, so the dialysis property of the anion exchange membrane 42 can be maintained during the diffusion dialysis process. Therefore, according to the present invention, the phosphate contained in the etching solution can be efficiently extracted (recovered) into the water. In the method for regenerating the etching solution of the present invention, before performing the extraction step (S3), the etching solution can also be filtered (S2; filtration step), but this is not an essential step. By performing the filtration step (S2), the insoluble components present in the etching solution can be removed, so that the anion exchange membrane 42 can be surely prevented from being blocked during the extraction step (S3). In addition, if necessary, after the extraction step (S3), the treatment solution containing phosphoric acid obtained by the extraction step (S3) can be concentrated (S4; concentration step). As described above, the method for regenerating the etching solution of the present invention regenerates the etching solution by the diffusion dialysis method of bringing the etching solution into contact with water through an anion exchange membrane and extracting the phosphate contained in the etching solution into the water. According to the present invention, of course, the treatment solution (recovered acid) can be remade into an etching solution and regenerated, and can also be regenerated into a state that can be used for various purposes other than the etching solution. In addition, due to the inclusion of a dialysis aid in the etching solution, when the Si concentration from silicon nitride in the etching solution becomes about 10 ppm, up to about 50 - 2000 ppm, or even a very high concentration of about 3000 ppm, the precipitation of silicon dioxide does not occur, and the dialysis property of the anion exchange membrane can be sufficiently maintained. As a result, the phosphate contained in the etching solution can be efficiently extracted into the water. In this way, according to the method for regenerating the etching solution of the present invention, not only the conventional etching solution but also a high-performance etching solution in which a precipitation inhibitor for suppressing the precipitation of silicon dioxide is blended in the etching solution can be regenerated. [Examples] Examples of the method for regenerating the etching solution using the present invention will be described below. In addition, the % written as the addition amount (content in the etching solution) of each component described in each example is by weight% unless otherwise specified. <Preparation of Etchant (Fatigue Solution)> [Example 1] In phosphoric acid with a concentration of 85% (manufactured by RASA Industries Co., Ltd.), a silicon nitride film was dissolved, and the Si concentration was adjusted to 200 ppm. By heating this solution at 80 - 100 °C to evaporate water, the phosphoric acid concentration was adjusted to 87%. Further, 3-aminopropyltrimethoxysilane (2%) and adipic dihydrazide (0.2%) as dialysis aids were added respectively to obtain the etchant (simulation solution) of Example 1. When using the etchant of Example 1, it is equivalent to performing an addition step of adding a dialysis aid to the etchant before the extraction step. [Example 2] The same operations as in Example 1 were performed except that only 3-aminopropyltriethoxysilane (3%) as a dialysis aid was added to obtain the etchant of Example 2. [Example 3] The same operations as in Example 1 were performed except that 3-aminopropyltriethoxysilane (3%) and hexafluorosilicic acid (0.001%) as dialysis aids were added respectively to obtain the etchant of Example 3. [Example 4] The same operations as in Example 1 were performed except that a hydrolyzate of 3-aminopropyltriethoxysilane (1.2%) and ammonium phosphate (0.1%) as dialysis aids were added respectively to obtain the etchant of Example 4. [Example 5] The same operations as in Example 1 were performed except that a hydrolyzate of 3-aminopropyltriethoxysilane (1.2%) and phosphorous acid (0.1%) as dialysis aids were added respectively to obtain the etchant of Example 5. [Example 6] In phosphoric acid with a concentration of 85% (manufactured by RASA Industries Co., Ltd.), a hydrolyzate of 3-aminopropyltrimethoxysilane (10.2%), the siloxane compound represented by the aforementioned chemical formula (2) (0.34%), and adipic dihydrazide (0.3%) as dialysis aids were added respectively. Next, a silicon nitride film was dissolved, and the Si concentration was adjusted to 2000 ppm. By heating this solution at 80 - 100 °C to evaporate water, the phosphoric acid concentration was adjusted to 87% to obtain the etchant of Example 6. When using the etchant of Example 6, it is equivalent to performing a preparation step of adding a dialysis aid to the etchant before etching a semiconductor. [Comparative Example 1] The same operations as in Example 1 were performed except that no dialysis aid was added (i.e., it does not contain a dialysis aid) to obtain the etchant of Comparative Example 1. <Regeneration Experiment> Diffusion dialysis was performed on the etchants of Examples 1 - 6 and Comparative Example 1 using the regeneration device 100 shown in Figure 1. Figure 3 is a graph showing the recovery rate of phosphoric acid recovered from the etching solutions of Examples 1 to 6 and Comparative Example 1. For the etching solution of Example 1, the phosphoric acid recovery rate was maintained at about 90% for 30 consecutive days, and the anion exchange membrane was not blocked. The etching solutions of Examples 2 to 5 also maintained a phosphoric acid recovery rate of about 90% or higher for at least 7 days. In addition, regeneration experiments after the 8th day were not conducted for Examples 2 to 5 because, based on the tendency observed in Example 1, it was predicted that Examples 2 to 5 would also be able to maintain the phosphoric acid recovery rate for at least about 30 days. For the etching solution of Example 6, the phosphoric acid recovery rate from the first day (Day 1) to the 7th day was about 73 - 74%, but even so, the anion exchange membrane was not blocked. In contrast, for the etching solution of Comparative Example 1 without a dialysis aid, the phosphoric acid recovery rate remained at about 60% from the first day (Day 1), and then the anion exchange membrane was blocked, so the regeneration experiment could not be continued. <Regeneration Etching Solution Performance Confirmation Experiment 1> To confirm whether the etching performance of the etching solution regenerated by the etching solution regeneration method of the present invention is not reduced compared to a brand - new etching solution, a performance confirmation experiment was conducted. In the performance confirmation experiment, first, the etching solution of Example 1 was supplied to the regeneration device 100, and the experiment was carried out for the regenerated etching solution after regeneration and the brand - new etching solution, and for both the "system without adding a dialysis aid" (Example 7, Comparative Example 2) and the "system adding a dialysis aid" (Example 8, Comparative Example 3). [System without adding a dialysis aid: Example 7, Comparative Example 2] Using the regenerated etching solution with the phosphoric acid concentration adjusted (87%) and the Si concentration in the solution adjusted (0 - 100 ppm), an etching experiment on a silicon oxide film (Example 7 - 1) and an etching experiment on a silicon nitride film (Example 7 - 2) were carried out. In addition, for the brand - new etching solution, an etching experiment on a silicon oxide film (Comparative Example 2 - 1) and an etching experiment on a silicon nitride film (Comparative Example 2 - 2) were also carried out in the same way. FIG. 4 is a graph showing the results of the etching experiments (without a dialysis aid) of Example 7 and Comparative Example 2. The results of the etching experiments on silicon oxide for Example 7-1 and Comparative Example 2-1 are shown in FIG. 4(a). The results of the etching experiments on silicon nitride for Example 7-2 and Comparative Example 2-2 are shown in FIG. 4(b). In the semiconductor manufacturing process having a silicon oxide film and a silicon nitride film as a sacrificial layer, it is desired to maintain a low etching rate for silicon oxide and a high etching rate for silicon nitride. Regarding the etching characteristics of silicon oxide, the Si concentration of the regenerated etching solution is in the range of 0 to 100 ppm, and an etching inhibition effect on silicon oxide equal to or higher than that of a brand-new etching solution was confirmed. Regarding the etching characteristics of silicon nitride, the Si concentration of the regenerated etching solution is in the range of 0 to 100 ppm, and an etching effect on silicon nitride equal to or higher than that of a brand-new etching solution was confirmed. In particular, the regenerated etching solution in the region with a low Si concentration had excellent results in the etching inhibition effect on silicon oxide compared with the brand-new etching solution. The reason is considered to be that the regenerated etching solution contains some Si compounds not derived from silicon nitride (for example, Si compounds from an etching inhibitor or a dialysis aid), and this Si compound has an effect of inhibiting the etching of silicon oxide. [System with a dialysis aid added: Example 8, Comparative Example 3] 3-aminopropyltrimethoxysilane (2%) and adipic dihydrazide (0.2%), which are used as dialysis aids, were respectively added to the regenerated etching solutions that had undergone adjustment of the phosphoric acid concentration (87%) and the Si concentration in the solution (0 to 200 ppm), and the etching experiment on the silicon oxide film (Example 8-1) and the etching experiment on the silicon nitride film (Example 8-2) were carried out using this solution. In addition, 3-aminopropyltrimethoxysilane (2%) and adipic dihydrazide (0.2%), which are used as dialysis aids, were also respectively added to the brand-new etching solution in the same way, and the etching experiment on the silicon oxide film (Comparative Example 3-1) and the etching experiment on the silicon nitride film (Comparative Example 3-2) were carried out using this solution. FIG. 5 is a graph showing the results of the etching experiments (with dialysis aids) of Example 8 and Comparative Example 3. The results of the etching experiments on silicon oxide of Example 8-1 and Comparative Example 3-1 are shown in FIG. 5(a). The results of the etching experiments on silicon nitride of Example 8-2 and Comparative Example 3-2 are shown in FIG. 5(b). Regarding the etching characteristics of silicon oxide, the Si concentration of the regenerated etching solution was in the range of 0 to 200 ppm, and an etching inhibition effect on silicon oxide equivalent to that of a brand-new etching solution was confirmed. Regarding the etching characteristics of silicon nitride, the Si concentration of the regenerated etching solution was in the range of 0 to 200 ppm, and an etching effect on silicon nitride equivalent to that of a brand-new etching solution was confirmed. It is considered that some Si compounds not derived from silicon nitride are contained in the regenerated etching solution. Therefore, in Example 7 and Comparative Example 2, the performance of the regenerated etching solution was superior to that of the brand-new etching solution (higher etching rate for silicon nitride and lower etching rate for silicon oxide). However, in Example 8 and Comparative Example 3, since 3-aminopropyltrimethoxysilane (2%) and adipic dihydrazide (0.2%) were added as dialysis aids, respectively, the brand-new etching solution also contained Si compounds not derived from silicon nitride. As a result, the performance difference between the regenerated etching solution and the brand-new etching solution was reduced. [Selectivity ratio] The selectivity ratio (R 1 ) obtained from the etching rate (R 2 ) of silicon nitride and the etching rate (R 1 / R 2 ) of silicon oxide by Examples 7 to 8 and Comparative Examples 2 to 3 is shown in Table 1 below. The larger the absolute value of the selectivity ratio (R 1 / R 2 ), the more the etching of silicon oxide can be inhibited, and at the same time, the higher the etchability for silicon nitride can be obtained. Therefore, an etching solution with excellent etching selectivity can be evaluated. The regenerated etching solutions of Examples 7 to 8 can achieve a selectivity ratio (R 1 / R 2 ) equal to or higher than that of the brand-new etching solutions of Comparative Examples 2 to 3, and are etching solutions that can be fully used. <Performance Confirmation Experiment 2 of the Regenerated Etchant> In addition, for the regenerated etchants obtained by supplying the etchants of Examples 2 to 6 to the regeneration device 100 for regeneration, performance confirmation experiments were also conducted for the "system without a dialysis aid" (Examples 9 to 13) and the "system with a dialysis aid" (Examples 14 to 18). Additionally, for comparison, the same performance confirmation experiments were also conducted for the etchants of Examples 2 to 6 themselves (Comparative Examples 4 to 8) with a dialysis aid added to the brand-new etchant. [Examples 9 to 13: System without a dialysis aid] Using the regenerated etchant with the phosphoric acid concentration adjusted (87%) and the Si concentration in the liquid adjusted (0 to 100 ppm), an etching experiment on the silicon oxide film (Examples 9-1 to 13-1) and an etching experiment on the silicon nitride film (Examples 9-2 to 13-2) were carried out. Figures 6 to 10 are graphs showing the results of the etching experiments (without a dialysis aid) of Examples 9 to 13. [Examples 14 to 18: System with a dialysis aid] The same dialysis aids as those used in Examples 2 to 6 were respectively added to the regenerated etchant with the phosphoric acid concentration adjusted (87%) and the Si concentration in the liquid adjusted (0 to 2000 ppm). Using this liquid, an etching experiment on the silicon oxide film (Examples 14-1 to 18-1) and an etching experiment on the silicon nitride film (Examples 14-2 to 18-2) were carried out. Figures 11 to 15 are graphs showing the results of the etching experiments (with a dialysis aid) of Examples 14 to 18. [Comparative Examples 4 to 8] Using the etchants of Examples 2 to 6 with a dialysis aid added to the brand-new etchant, an etching experiment on the silicon oxide film (Comparative Examples 4-1 to 8-1) and an etching experiment on the silicon nitride film (Comparative Examples 4-2 to 8-2) were carried out. The results of the etching experiments of Comparative Examples 4 to 8 are shown together in Figures 11 to 15. [Selectivity] The selectivity (R 1 ) obtained from the etching rate of silicon nitride (R 2 ) and the etching rate of silicon oxide (R 1 / R 2 ) in Examples 9 to 13 is shown in Table 2 below. For the regenerated etchants of Examples 9 to 13, the absolute value of the selectivity (R 1 / R 2 ) is large enough, and it is an etchant that can be fully used. The etching rate of silicon nitride (R 1 ) and the etching rate of silicon oxide (R 2 )The obtained selectivity ratio (R 1 / R 2 ) is shown in Table 3 below. In addition, the etching rates of silicon nitride (R 1 ) and the etching rates of silicon oxide (R 2 ) obtained from Comparative Examples 4 to 8 1 / R 2 ) are shown in Table 4 below. The regenerated etching solutions of Examples 14 to 18 can achieve a selectivity ratio (R 1 / R 2 ) equal to or higher than that of the etching solutions of Comparative Examples 4 to 8 in which a dialysis aid is added to a brand-new etching solution, and are etching solutions that can be fully utilized. [Industrial Applicability] The method for regenerating an etching solution of the present invention is a method for regenerating an etching solution used in semiconductor manufacturing having a silicon oxide film and a silicon nitride film as a sacrificial layer, and can be used, for example, for regenerating an etching solution used in the manufacture of 2D NAND, 3D NAND, CMOS, DRAM, 3DRAM, logic ICs, etc. 100: Regeneration device 10: Stock solution storage tank 11: Stock solution pump 12: Filtering device 20: Water storage tank 21: Water pump 30: Aid storage tank 31: Aid addition pump 40: Diffusion dialysis device 41: Frame 42: Anion exchange membrane 43: Space 50: Treatment solution storage tank 51: Treatment solution pump 52: Concentration device 60: Drainage solution storage tank 61: Drainage solution pump S1: Addition step S2: Filtration step S3: Extraction step S4: Concentration step [Fig. 1] is a schematic structural diagram of a regeneration device for regenerating an etching solution. [Fig. 2] is a flowchart showing a method for regenerating an etching solution related to the present invention. [Fig. 3] is a graph of the recovery rate of phosphoric acid recovered from the etching solutions of Examples 1 to 6 and Comparative Example 1. [Fig. 4] is a graph of the results of the etching experiments (without a dialysis aid) of Example 7 and Comparative Example 2. [Fig. 5] is a graph of the results of the etching experiments (with a dialysis aid) of Example 8 and Comparative Example 3. [Fig. 6] is a graph of the results of the etching experiment (without a dialysis aid) of Example 9. [Fig. 7] is a graph of the results of the etching experiment (without a dialysis aid) of Example 10. [Fig. 8] is a graph of the results of the etching experiment (without a dialysis aid) of Example 11. [Fig. 9] is a graph of the results of the etching experiment (without a dialysis aid) of Example 12. [Fig. 10] is a graph of the results of the etching experiment (without a dialysis aid) of Example 13. [Fig. 11] is a graph of the results of the etching experiments (with a dialysis aid) of Example 14 and the etching experiment of Comparative Example 4. [Fig. 12] is a graph of the results of the etching experiments (with a dialysis aid) of Example 15 and the etching experiment of Comparative Example 5. [Fig. 13] is a graph of the results of the etching experiments (with a dialysis aid) of Example 16 and the etching experiment of Comparative Example 6. [Fig. 14] is a graph of the results of the etching experiments (with a dialysis aid) of Example 17 and the etching experiment of Comparative Example 7. [Fig. 15] is a graph of the results of the etching experiments (with a dialysis aid) of Example 18 and the etching experiment of Comparative Example 8.

Claims

1. A method for regenerating an etching solution, comprising a method for regenerating an etching solution of an inorganic acid substrate used or used in the etching of a semiconductor by diffusion dialysis, and comprising: an extraction step of extracting an inorganic acid contained in the etching solution into water by contacting the etching solution containing a dialysis aid through an anion exchange membrane; wherein the inorganic acid is phosphoric acid.

2. The method for regenerating the etching solution as claimed in claim 1, comprising: adding a dialysis aid to the etching solution before the aforementioned extraction step to prepare an etching solution containing the aforementioned dialysis aid.

3. The method for regenerating the etchant as claimed in claim 1, comprising: a preparation step of adding all or part of a dialysis aid to the etchant before etching the aforementioned semiconductor, thereby preparing an etchant containing the aforementioned dialysis aid.

4. The method for regenerating the etching solution as claimed in claim 2 or 3, wherein the aforementioned dialysis aid is a compound containing heteroatoms.

5. The method for regenerating the etching solution as claimed in claim 4, wherein the aforementioned heteroatom-containing compound is a compound containing Si atoms, a compound containing N atoms, and / or a compound containing P atoms.

6. The method for regenerating the etching solution as claimed in claim 5, wherein the aforementioned Si-atom-containing compound is a silane compound having three or fewer alkoxy groups, hydroxyl groups, and / or functional groups that are precursors to hydroxyl groups in its molecular structure, and / or a silane compound having four or more alkoxy groups, hydroxyl groups, and / or functional groups that are precursors to hydroxyl groups in its molecular structure, and / or a silane compound containing halogen atoms.

7. The method for regenerating the etching solution as claimed in claim 5, wherein the aforementioned N-atom-containing compound is a hydrazine and / or an ammonium compound.

8. The method for regenerating the etching solution as claimed in claim 5, wherein the aforementioned compound containing P atoms is a phosphonic acid compound.

9. A method for regenerating an etchant as claimed in any of claims 1 to 3, wherein the etchant contains Si from the aforementioned semiconductor at a concentration of a predetermined concentration or higher.

10. A method for regenerating the etchant as claimed in any of claims 1 to 3, wherein the etchant is a fatigue solution used in the etching of the aforementioned semiconductor.

11. A method for regenerating an etchant as claimed in any of claims 1 to 3, wherein the aforementioned extraction step is performed by countercurrent contact between the aforementioned etchant and the aforementioned water through an anion exchange membrane.

12. A method for regenerating an etchant as claimed in any of claims 1 to 3, wherein the aforementioned semiconductor is a semiconductor having a silicon nitride film as a sacrificial layer.

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