Decomposition inhibitor for transition metal oxidants

Abstract

Provided is a decomposition inhibitor for transition metal oxidants, the decomposition inhibitor comprising a compound represented by formula (1). (1): A-(X)n, where A is an aromatic group, a group having a carbon double bond, or a group having a carbon triple bond, X is an electron donating group, and n is an integer.

Description

Decomposition inhibitor for transition metal oxidizers

[0001] The present invention relates to a semiconductor processing solution used in metal wiring processing in the manufacturing process of semiconductor elements.

[0002] Wiring layers are formed within semiconductor elements to transmit electrical signals generated by transistors to the outside. Semiconductor elements are becoming increasingly miniaturized, and using materials with low electromigration resistance or high resistance can reduce the reliability of the semiconductor elements and hinder high-speed operation. Therefore, wiring materials with high electromigration resistance and low resistance are desired. Materials with high electromigration resistance and low resistance have traditionally been used, but tungsten, cobalt, molybdenum, and ruthenium have recently been considered. Forming wiring layers on semiconductor elements involves a process for processing the wiring material, which can be performed using dry or wet etching. In particular, wet etching, which has high throughput and lower equipment costs compared to dry etching, is being considered for use in next-generation wiring formation processes. In recent years, in wet etching, from the perspectives of further cost reduction and environmental impact, there has been a demand for recovering semiconductor processing solutions after wafer processing and reusing them after circulating and filtering them. By reusing the semiconductor processing liquid, it is possible to reduce the amount of semiconductor processing liquid used and the amount of waste liquid, compared to when the processing liquid is not reused.

[0003] However, when a semiconductor processing solution etches transition metals by oxidative dissolution, transition metal oxides or transition metal oxide ions are present in the processing solution after processing. Taking the etching of ruthenium by hypobromite ions as an example, ruthenium is oxidized by hypobromite ions under alkaline conditions to become RuO ４ － The RuO dissolved in the treatment solution in this way is ４ － The ion is RuO ４ － RuO is formed by the disproportionation reaction of ions ４ and RuO２ These ions react with hypobromite ions, resulting in a decrease in the concentration of hypobromite ions effective for etching. Therefore, the more times the treatment solution is reused and the longer the reuse time, the more significant the decrease in the concentration of hypobromite ions due to the reaction between the eluted transition metal oxide ions and hypobromite ions becomes, resulting in a problem of a decrease in etching performance. From the viewpoint of reuse of the treatment solution, it is important to improve the stability of hypobromite ions in the treatment solution in which transition metal oxides are present.

[0004] JP 2010-189393 A

[0005] Patent Document 1 proposes a hypobromous acid solution of less than 30% by weight containing cyanuric acid in an amount not exceeding 1 ppm by weight as a stabilizer for hypobromous acid. It is described that the addition of low concentrations of cyanuric acid stabilizes the inherently unstable hypobromous acid, resulting in a shelf life of up to six months (in a sealed, opaque container). However, it is also described that the pH range of hypobromous acid solutions that are most stabilized and most reactive with cyanuric acid is 8 to 9. Furthermore, the inventors' studies have found that when transition metals are etched using a hypobromous acid solution of this pH and the treatment solution is reused after etching, the etching performance for transition metals is reduced. This is presumably because the addition of cyanuric acid is believed to suppress decomposition due to disproportionation of hypobromous acid, and fails to suppress decomposition of hypobromous acid by transition metal oxides oxidized and dissolved in the treatment solution.

[0006] Therefore, an object of the present invention is to provide a decomposition inhibitor that, when added to a semiconductor processing solution, can inhibit the decomposition of a transition metal oxidizing agent caused by oxidized and dissolved transition metal oxides and / or oxide ions, thereby enabling the semiconductor processing solution to be reused. In this specification, "transition metal oxides and / or oxide ions" refers to one or more transition metal oxides and transition metal oxide ions. Hereinafter, this term will also be referred to as "transition metal oxidant."

[0007] The present inventors have conducted extensive research to solve the above problems. As a result, they have found that a compound having an electron-donating group and an aromatic group, a group having a carbon-carbon double bond, or a group having a carbon-carbon triple bond can act as an inhibitor for inhibiting the decomposition of an oxidizing agent for a transition metal, and have completed the present invention. Specifically, the present invention has the following features.

[0008] Item 1: A decomposition inhibitor for an oxidizing agent for a transition metal, comprising a compound represented by the following formula (1): A-(X): ｎ(1) A: aromatic group, group having a carbon-carbon double bond, or group having a carbon-carbon triple bond; X: electron-donating group; n: integer. Item 2. The decomposition inhibitor according to Item 1, wherein in formula (1), A is an aromatic group and n is 1 or 2. Item 3. The decomposition inhibitor according to Item 1 or 2, wherein in formula (1), X is an amino group or an alkoxy group. Item 4. The decomposition inhibitor for a transition metal oxidizing agent according to any one of Items 1 to 3, wherein A in formula (1) has a hydrophilic group in addition to X. Item 5. The decomposition inhibitor for a transition metal oxidizing agent according to Item 4, wherein the hydrophilic group is a carboxyl group. Item 6. The decomposition inhibitor according to any one of Items 1 to 5, which is added to a semiconductor processing liquid and used for recycling the semiconductor processing liquid. Item 7. The decomposition inhibitor according to any one of Items 1 to 6, wherein the transition metal comprises at least one metal selected from the group consisting of Ru, Rh, Ti, Ta, Co, Cr, Hf, Os, Pt, Ni, Mn, Cu, Zr, La, Mo, and W. Item 8. The decomposition inhibitor for a transition metal oxidizing agent according to any one of Items 1 to 7, wherein the transition metal is Ru. Item 9. A semiconductor processing solution comprising the decomposition inhibitor for a transition metal oxidizing agent according to any one of Items 1 to 8, and an oxidizing agent for a transition metal. Item 10. The semiconductor processing solution according to Item 9, wherein the concentration of the decomposition inhibitor is 1 ppm by mass or more and 10,000 ppm by mass, relative to the total mass of the semiconductor processing solution. Item 11. The semiconductor processing solution according to Item 9 or 10, wherein the transition metal oxidizing agent is at least one halogen oxygen acid ion selected from the group consisting of hypobromite ion, hypochlorite ion, and periodate ion, and the total concentration of all of the transition metal oxidizing agents is 50 ppm by mass or more and 35% by mass or less, based on the total mass of the semiconductor processing solution. Item 12. The semiconductor processing solution according to Item 11, wherein the transition metal oxidizing agent is hypobromite ion and hypochlorite ion. Item 13. The semiconductor processing solution according to any one of Items 9 to 12, further comprising a transition metal oxidant. Item 14. The semiconductor processing solution according to any one of Items 9 to 13, further comprising a filtration lubricant. Item 15. The semiconductor processing solution according to Item 14, wherein the filtration lubricant is an onium ion. Item 16. A method for etching a semiconductor wafer, comprising contacting a semiconductor wafer containing a transition metal with the semiconductor processing solution according to any one of Items 9 to 15, to etch the transition metal.Item 17. A method for manufacturing a semiconductor device, comprising the etching method according to Item 16 in a process.

[0009] According to the present invention, there is provided an inhibitor of the decomposition of an oxidizing agent for a transition metal, which, when added to a semiconductor processing solution, inhibits the decomposition of the oxidizing agent for a transition metal by a transition metal oxidant, thereby making the semiconductor processing solution reusable.

[0010] 1 is a diagram showing an outline of equipment used in an etching step in a method for manufacturing a semiconductor device.

[0011] (Decomposition Inhibitor of Oxidizing Agent for Transition Metal) The decomposition inhibitor of an oxidizing agent for a transition metal (hereinafter also referred to as decomposition inhibitor) of this embodiment is composed of a compound represented by formula (1). Although the mechanism is not clear, when a group having π electrons has a structure in which an electron imbalance occurs due to the attached electron-donating group, as in the compound represented by formula (1), it is easily oxidized by a specific oxidizing agent. As a result, it is presumed that the decomposition inhibitor is oxidized to a transition metal oxidant instead of the transition metal oxidizing agent, thereby inhibiting the decomposition of the transition metal oxidizing agent. Furthermore, when the transition metal oxidant is a transition metal oxidant that gasifies, for example, RuO ４ In this case, the decomposition inhibitor is used to ４ is reduced to RuO ２ At this time, the transition metal oxidized compound RuO ４ RuO does not gasify ２ As a result, RuO ４ Gas is no longer released from the semiconductor processing solution. Therefore, when the transition metal is ruthenium, the decomposition inhibitor of this embodiment also has a gas suppression effect. A-(X) ｎ (1) A: aromatic group, group having a carbon-carbon double bond, or group having a carbon-carbon triple bond; X: electron-donating group; n: integer

[0012] In formula (1), A is an aromatic group, a group having a carbon-carbon double bond, or a group having a carbon-carbon triple bond. From the viewpoint of stability against a transition metal oxidizing agent, A is most preferably an aromatic group. Examples of the aromatic group include, when n is 1, an aryl group selected from a phenyl group, a naphthyl group, and a phenanthryl group; and, when n is 2 or more, a group in which hydrogen atoms bonded to an aryl group selected from a phenyl group, a naphthyl group, and a phenanthryl group are further substituted with n-1 Xs. As will be described later, when A has a hydrophilic group in addition to Xs, some hydrogen atoms at positions other than the positions to which Xs are bonded in the aromatic group are substituted with the hydrophilic groups.

[0013] The group having a carbon-carbon double bond is not particularly limited as long as it has a structure in which an electron-donating group causes a bias in the electrons in the double bond portion. For example, when n is 1, examples of the group include a vinyl group or a group derived from an alkene, such as a propenyl group or a butenyl group.

[0014] The group having a carbon triple bond is not particularly limited as long as it has a structure in which an electron-donating group causes a bias in the electrons at the triple bond portion. For example, when n is 1, examples of the group include groups derived from alkynes, such as an ethynyl group and a propynyl group.

[0015] X is an electron-donating group, and examples thereof include an amino group, an alkoxy group, a methyl group, or a hydroxy group. Examples of alkoxy groups include a methoxy group, an ethoxy group, a propyloxy group, and a phenoxy group. Because of their strong electron-donating properties and high solubility in water, amino groups, methoxy groups, and ethoxy groups are preferred as electron-donating groups. When an alkoxy group is selected as X, an alkylene group having 1 to 5 carbon atoms or 2 to 5 carbon atoms may be present between A and X, in which some methylene groups may be substituted with -O-. However, -O- groups do not occur consecutively. When an alkoxy group is selected as X, some hydrogen atoms in the hydrocarbon chain of the alkoxy group may be substituted with a hydrophilic group. The alkyl group in the alkoxy group preferably has 1 to 3 carbon atoms. The inclusion of the hydrophilic group more effectively suppresses decomposition of the transition metal oxidizing agent. Examples of such hydrophilic groups include a carboxyl group, a sulfo group, an aldehyde group, a thiol group, a cyano group, and an amide group. In view of stability against oxidizing agents for transition metals, a carboxyl group or a sulfo group is preferred.

[0016] n is an integer, preferably 1 or more and 6 or less, more preferably 1 or more and 2 or less, and most preferably 1, from the viewpoint of electron bias due to electron donating properties.

[0017] Furthermore, A in formula (1) may have a hydrophilic group in addition to X. By having a hydrophilic group, decomposition of the transition metal oxidizing agent can be more effectively suppressed. Examples of such a hydrophilic group include a carboxyl group, a sulfo group, an aldehyde group, a thiol group, a cyano group, and an amide group. In terms of stability against the transition metal oxidizing agent, a carboxyl group or a sulfo group is preferred.

[0018] Examples of the compound represented by formula (1) include aniline, methoxybenzene, ethoxybenzene, propyloxybenzene, diphenyl ether, phenol, toluene, 1,2-diaminobenzene, 1,3-diaminobenzene, 1,4-diaminobenzene, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, 2,3-diaminobenzoic acid, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 2,6-diaminobenzoic acid, 3,4-diaminobenzoic acid, 3,5-diaminobenzoic acid, 2-aminobenzenesulfonic acid, and 3-aminobenzenesulfonic acid. Phenylic acid, 4-aminobenzenesulfonic acid, 2,3-diaminobenzenesulfonic acid, 2,4-diaminobenzenesulfonic acid, 2,5-diaminobenzenesulfonic acid, 2,6-diaminobenzenesulfonic acid, 3,4-diaminobenzenesulfonic acid, 3,5-diaminobenzenesulfonic acid, 2-aminotoluene, 3-aminotoluene, 4-aminotoluene, 2,3-diaminotoluene, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,6-diaminotoluene, 3,4-diaminotoluene, 3,5-diaminotoluene, 2-methoxyaniline ... ethoxyaniline, 4-methoxyaniline, 2,3-dimethoxyaniline, 2,4-dimethoxyaniline, 2,5-dimethoxyaniline, 2,6-dimethoxyaniline, 3,4-dimethoxyaniline, 3,5-dimethoxyaniline, 2-ethoxyaniline, 3-ethoxyaniline, 4-ethoxyaniline, 2,3-diethoxyaniline, 2,4-diethoxyaniline, 2,5-diethoxyaniline, 2,6-diethoxyaniline, 3,4-diethoxyaniline, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1,4-dimethoxybenzene, 2 -methoxybenzoic acid, 3-methoxybenzoic acid, 4-methoxybenzoic acid, 2,3-dimethoxybenzoic acid, 2,4-dimethoxybenzoic acid, 2,5-dimethoxybenzoic acid, 2,6-dimethoxybenzoic acid, 3,4-dimethoxybenzoic acid, 3,5-dimethoxybenzoic acid, 1,2-diethoxybenzene, 1,3-diethoxybenzene, 1,4-diethoxybenzene, 2-ethoxybenzoic acid, 3-ethoxybenzoic acid, 4-ethoxybenzoic acid, 2,3-diethoxybenzoic acid, 2,4-diethoxybenzoic acid, 2,5-diethoxybenzoic acid, 2,6-diethoxybenzoic acid, 3,4-diethoxybenzoic acid, 3,5-diethoxybenzoic acid, 2-methoxybenzenesulfonic acid, 3-methoxybenzenesulfonic acid, 4-methoxybenzenesulfonic acid, 2,3-methoxybenzenesulfonic acid, 2,4-dimethoxybenzenesulfonic acid, 2,5-dimethoxybenzenesulfonic acid, 2,6-dimethoxybenzenesulfonic acid, 3,4-dimethoxybenzenesulfonic acid, 3,5-dimethoxybenzenesulfonic acid, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethoxytoluene, 2,4-dimethoxy

[0033] Examples of the dimethoxytoluene include 2,5-dimethoxytoluene, 2,6-dimethoxytoluene, 3,4-dimethoxytoluene, 3,5-dimethoxytoluene, 1-propene-1-amine, 1-butene-1-amine, 1-pentene-1-amine, 2-butane-2,3-diamine, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, ethynylamine, methoxyethyn, 1-methoxypropyne, dimethoxypropene, dimethoxybutene, and dimethoxyacetylene. Preferably, aniline, 1,2-diaminobenzene, 1,3-diaminobenzene, 1,4-diaminobenzene, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, 2,3-diaminobenzoic acid, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 2,6-diaminobenzoic acid, 3,4-diaminobenzoic acid, 3,5-diaminobenzoic acid, 2-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid, 4-aminobenzenesulfonic acid, 2,3-diaminobenzenesulfonic acid, 2,4-diaminobenzenesulfonic acid, and 2,5-diaminobenzenesulfonic acid. acid, 2,6-diaminobenzenesulfonic acid, 3,4-diaminobenzenesulfonic acid, 3,5-diaminobenzenesulfonic acid, methoxybenzene, ethoxybenzene, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1,4-dimethoxybenzene, 2-methoxybenzoic acid, 3-methoxybenzoic acid, 4-methoxybenzoic acid, 2-ethoxybenzoic acid, 3-ethoxybenzoic acid, 4-ethoxybenzoic acid, 2,3-dimethoxyaniline, 2,4-dimethoxyaniline, 2,5-dimethoxyaniline, 2,6-dimethoxyaniline, 3,4-dimethoxyaniline, 3,Preferably, it is at least one selected from the group consisting of 5-dimethoxyaniline, phenoxyacetic acid, 2-phenoxypropionic acid, and 2-methoxyphenoxyacetic acid, and most preferably at least one selected from the group consisting of 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, 2,3-diaminobenzoic acid, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 2,6-diaminobenzoic acid, 3,4-diaminobenzoic acid, 3,5-diaminobenzoic acid, 2-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid, 4-aminobenzenesulfonic acid, 2-methoxybenzoic acid, 3-methoxybenzoic acid, 4-methoxybenzoic acid, phenoxyacetic acid, 2-phenoxypropionic acid, and 2-methoxyphenoxyacetic acid.

[0019] The decomposition inhibitor for a transition metal oxidizing agent of this embodiment is composed of the compound represented by formula (1) as described above, and is particularly preferably used by being added to a semiconductor processing solution described later, and can also be used to reuse a used semiconductor processing solution. Furthermore, as described later, the decomposition inhibitor for a transition metal oxidizing agent of this embodiment, i.e., the compound represented by formula (1), can be used to suppress the decomposition of RuO when the semiconductor processing solution of this embodiment is used on an object containing a transition metal, particularly ruthenium. ４ It can also be used as a gas generation inhibitor.

[0020] (Semiconductor Processing Solution) The solution containing the inhibitor for the decomposition of a transition metal oxidizing agent can be suitably used as a semiconductor processing solution (hereinafter also referred to as a processing solution). The semiconductor processing solution preferably contains an oxidizing agent for a transition metal in order to etch the transition metal. The semiconductor wafer to be etched preferably contains at least one transition metal selected from Ru, Rh, Ti, Ta, Co, Cr, Hf, Os, Pt, Ni, Mn, Cu, Zr, La, Mo, and W, more preferably Ru, Mo, or W, and most preferably Ru.

[0021] The concentration of the decomposition inhibitor is preferably 1 mass ppm or more and 10,000 mass ppm or less, based on the total mass of the semiconductor processing solution. If the amount of decomposition inhibitor added is too small, the probability of reaction with the transition metal oxidant is reduced when used as a semiconductor processing solution, resulting in insufficient decomposition inhibitor effect. On the other hand, if the amount added is too large, the decomposition inhibitor may react with the transition metal oxidant contained in the processing solution, resulting in a decrease in the concentration of the transition metal oxidant. Therefore, the concentration of the decomposition inhibitor contained in the processing solution of the present invention is preferably 1 mass ppm or more and 10,000 mass ppm or less, and more preferably 10 mass ppm or more and 5,000 mass ppm or less. Furthermore, when decomposition inhibitors are added, only one type may be added, or two or more types may be added in combination. Even when two or more types of decomposition inhibitors are included, as long as the total concentration of the decomposition inhibitors is within the above-mentioned concentration range, the decrease in the concentration of the transition metal oxidant due to the transition metal oxidant can be effectively suppressed. When two or more types of decomposition inhibitors are contained, for example, combinations of two or more types of aminobenzoic acid and methoxybenzoic acid can be used, and specific examples include combinations of 2-aminobenzoic acid and 3-aminobenzoic acid, 2-methoxybenzoic acid and 3-methoxybenzoic acid, or 2-aminobenzoic acid and 2-methoxybenzoic acid.

[0022] (Reuse of Semiconductor Processing Solution) The semiconductor processing solution of this embodiment can be reused as a semiconductor processing solution even after processing a semiconductor wafer containing the above-mentioned transition metals. This is because the decomposition inhibitor can effectively suppress decomposition of the transition metal oxidizing agent even if the transition metal used in the semiconductor wafer is oxidized and dissolved in the semiconductor processing solution. The number of times the semiconductor processing solution is reused is not particularly limited, but it may be reused until the decrease in etching rate due to the decrease in oxidizing agent concentration exceeds the allowable range. As a guideline for the oxidizing agent concentration, a residual rate of 60% or more relative to the concentration at the time of addition is preferably 75% or more, more preferably 90% or more.

[0023] (Oxidizing Agent for Transition Metals) The semiconductor processing solution of this embodiment preferably contains, as an oxidizing agent for transition metals (also simply referred to as an oxidizing agent in this specification), at least one halogen oxyacid ion selected from the group consisting of hypobromite ions, hypochlorite ions, and periodate ions, and more preferably at least one halogen oxyacid ion selected from the group consisting of hypobromite ions and hypochlorite ions. The concentration of the oxidizing agent contained in the semiconductor processing solution of this embodiment is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 50 ppm by mass or more and 35.0% by mass or less. When the oxidizing agent in the semiconductor processing solution of this embodiment contains a halogen oxygen acid ion, and when hypobromite ion or hypochlorite ion is selected as the halogen oxygen acid ion, the concentration of the hypobromite ion or hypochlorite ion is preferably 50 ppm by mass or more and 5.0% by mass or less, and more preferably 100 ppm by mass or more and 3.0% by mass or less, relative to the total mass of the processing solution, from the viewpoint of being able to dissolve transition metals, although not particularly limited thereto. When periodate ion is selected as the halogen oxygen acid ion in the semiconductor processing solution of this embodiment, the addition of orthoperiodate ion or metaperiodate ion is preferred from the viewpoint of being able to dissolve transition metals, although not particularly limited thereto. Furthermore, since these ions are ionized when dissolved in water, salts of orthoperiodic acid and metaperiodic acid may also be added. In particular, orthoperiodate ion is more preferred from the viewpoint of being free of sodium and having a stable composition. In view of the solubility of the semiconductor processing solution, the content of periodate ions is preferably 0.5% by mass to 35.0% by mass, more preferably 2.0% by mass to 8.0% by mass, based on the total mass of the semiconductor processing solution.

[0024] When the oxidizing agent contained in the semiconductor processing solution of this embodiment is the halogen oxygen acid ion, the halogen oxygen acid ion may be one type or two or more types. The inclusion of multiple types may stabilize the etching rate and improve stability during reuse. For example, when hypobromite ion is contained as the first halogen oxygen acid ion, bromide ion is generated as consumption due to oxidation or decomposition due to disproportionation progresses. A decrease in the concentration of halogen oxygen acid ion causes a decrease in the etching rate. However, if the processing solution contains hypochlorite ion as the second halogen oxygen acid ion, the generated bromide ion can be oxidized and converted to hypobromite ion. This facilitates stabilization of the etching rate. For the above reasons, when hypobromite ion is contained in the semiconductor processing solution of this embodiment, it is preferable that hypochlorite ion also be present. The concentration of hypochlorite ion is not limited as long as it does not deviate from the spirit of the present invention, but is preferably 50 ppm by mass or more and 5.0% by mass or less. When the concentration of hypochlorite ions is less than 50 mass ppm, Br － The ruthenium cannot be efficiently oxidized, and the etching rate of ruthenium decreases. On the other hand, if the amount of hypochlorite ions added is greater than 5.0 mass%, the stability of the hypochlorite ions decreases and the decomposition of hypobromite ions due to the reaction between hypochlorite ions and hypobromite ions is promoted, which is not appropriate. The concentration of hypochlorite ions is more preferably 50 mass ppm or more and 3.0 mass% or less, and most preferably 100 mass ppm or more and 1.0 mass% or less.

[0025] (Decomposition Products) The processing solution of this embodiment may contain at least one ion selected from the group consisting of bromide ions, bromite ions, bromate ions, chloride ions, chlorite ions, chlorate ions, iodide ions, triiodide ions, and iodate ions. These ions are decomposition products of the respective halogen oxygen acid ions and are highly likely to be mixed into the solution during the manufacturing process of the solution containing halogen oxygen acid ions. However, the concentration of these ions does not affect the oxidizer decomposition suppression effect of this embodiment. Therefore, these decomposition product ions may be contained in any amount within the scope of the present invention. Although the concentration of these ions is not particularly limited, specifically, the semiconductor processing solution preferably contains these ions in a range of 1 ppb to 1% by mass. Considering the stability of the halogen oxygen acid ions, a range of 1 ppb to 100 ppm by mass is more preferable.

[0026] (pH) The pH of the semiconductor processing solution of this embodiment is preferably 8.5 to 13.0. Within this range, there are preferred pH ranges depending on the halogen oxygen acid ions selected. For example, when one or more of hypobromite ions and hypochlorite ions are selected as the halogen oxygen acid ions, the pH of the semiconductor processing solution is preferably 10.0 to 13.0, more preferably 12.0 to 12.6, from the viewpoints of dissolution ability, smoothness, and etching performance stability. When periodate ions are contained as the halogen oxygen acid ions contained in the semiconductor processing solution of this embodiment, the pH of the semiconductor processing solution is preferably 8.5 to 11.0, more preferably 9.0 to 10.0, from the viewpoints of dissolution ability, smoothness, and etching performance stability. In this specification, pH is a value at 25°C.

[0027] (Transition Metal Oxidant) When a transition metal is etched using the semiconductor processing solution of this embodiment, the transition metal is oxidized and dissolved in the processing solution after processing as a transition metal oxidant. When the transition metal is ruthenium, RuO ４ , RuO ４ － , RuO ４ ２－, RuO ２ However, when the transition metal is tungsten, WO ３ , W.O. ４ ２－ However, if the transition metal is molybdenum, MoO ２ , MоO ４ ２－ is oxidized and dissolved in the treatment solution as a transition metal oxidant. There are no particular restrictions on the concentration of the transition metal oxidant in the treatment solution after reuse, but the concentration range of the transition metal oxidant in the treatment solution is preferably 0.0001 μmol / L to 0.01 mol / L, and more preferably 0.001 μmol / L to 100 μmol / L. If the concentration of the transition metal oxidant is lower than 0.0001 μmol / L, it will not react efficiently with the decomposition inhibitor. If the concentration of the transition metal oxidant is higher than 0.01 mol / L, the decomposition inhibitor will not be able to sufficiently inhibit the decomposition of the oxidant.

[0028] (Others) The semiconductor processing solution of this embodiment may contain other additives that have conventionally been used in semiconductor processing solutions, as long as the additives do not impair the object of the present invention. For example, other additives that can be added include acids, metal corrosion inhibitors, water-soluble organic solvents, fluorine compounds, reducing agents, complexing agents, chelating agents, surfactants, antifoaming agents, pH adjusters, and stabilizers. These additives may be added alone or in combination.

[0029] An acid or alkali can be added to the semiconductor processing solution of this embodiment as a pH adjuster. As the alkali, an organic alkali is preferably used because it does not contain metal ions that cause problems in semiconductor manufacturing. Among these, tetraalkylammonium hydroxide is preferred, and tetramethylammonium hydroxide is more preferred, because it contains a large number of hydroxide ions per unit weight and is readily available as a high-purity product.

[0030] The water contained in the semiconductor processing solution of this embodiment is preferably water from which metal ions, organic impurities, particles, etc. have been removed by distillation, ion exchange treatment, filtration, various adsorption treatments, etc., and is particularly preferably pure water or ultrapure water. Such water can be obtained by known methods widely used in semiconductor manufacturing.

[0031] The semiconductor processing solution of this embodiment is preferably stored at low temperature and / or protected from light. Storage at low temperature and / or protected from light is expected to have the effect of suppressing decomposition of the oxidizing agent in the semiconductor processing solution. Furthermore, storing the semiconductor processing solution in a container filled with an inert gas prevents carbon dioxide from being mixed in, thereby maintaining the stability of the semiconductor processing solution. Furthermore, the inner surface of the container, i.e., the surface that comes into contact with the semiconductor processing solution, is preferably made of glass or an organic polymer material. This is because, if the inner surface of the container is made of glass or an organic polymer material, the inclusion of impurities such as metals, metal oxides, and organic substances can be further reduced.

[0032] (Filtering Lubricant) The semiconductor processing solution of this embodiment may contain onium ions as a filtering lubricant for improving the efficiency of the filtering step aimed at removing particles and impurities in the semiconductor device manufacturing method. The surface tension of the semiconductor processing solution containing onium ions as a filtering lubricant is important from the viewpoint of improving the efficiency of the filtering step. If the surface tension of the semiconductor processing solution containing a filtering lubricant is low, the onium ions may be removed in the filtering step. Therefore, it is desirable that the surface tension of the semiconductor processing solution containing a filtering lubricant be 60 mN / m or more and 75 mN / m or less. Furthermore, when ruthenium is contained in the semiconductor wafer, RuO generated during etching of the ruthenium may be removed. ４ － and RuO ４ ２－ By interacting with RuO ４ Gas and concomitantly produced RuO ２ As described above, the surface tension of the semiconductor processing solution containing the filtration lubricant is the key to maintaining these effects at a high level. If the surface tension of the semiconductor processing solution containing the filtration lubricant is less than 60 mN / m, the onium ions are easily removed by the filtration process, and the good surface smoothness and RuO ４It becomes difficult to maintain the gas suppression effect. One method for increasing the surface tension is to add a large amount of salt. However, if an oxidizing agent is contained in the semiconductor processing solution of this embodiment, the stability of the oxidizing agent may decrease due to a reaction between the salt and the oxidizing agent, or etching may be inhibited due to a high concentration of salt. For these reasons, the surface tension is preferably 75 mN / m or less.

[0033] The filtration process will now be described. In semiconductor wafer manufacturing, particle adhesion to wafers reduces yield, so filtration of semiconductor processing solutions is performed to remove particles from the semiconductor processing solution. For cutting-edge semiconductor wafers, the wiring width is extremely narrow, ranging from a few nanometers to several tens of nanometers, so the pore size of the filter used in the filtration process must be of a similar size. However, the smaller the pore size of the filter, the more easily onium salts or onium ions are adsorbed and removed. This reduces the onium ion concentration in the semiconductor processing solution, impairing its functionality as a semiconductor processing solution. However, this reduction in onium ion concentration can be avoided by controlling the surface tension of the semiconductor processing solution containing a filtration lubricant. Specifically, the surface tension of water is approximately 73 mN / m at 25°C, and by approaching this value, it is possible to suppress adsorption of onium salts or onium ions to the filter. That is, by controlling the surface tension of a semiconductor processing solution containing a filtration lubricant to 60 mN / m or more and 75 mN / m or less, adsorption of onium salts or onium ions to a filter can be suppressed, and the semiconductor processing solution containing a filtration lubricant can be used without impairing its functionality. For these reasons, the surface tension is 60 mN / m or more and 75 mN / m or less, preferably 68 mN / m or more and 75 mN / m or less, and most preferably 71 mN / m or more and 73 mN / m or less. Here, the surface tension in this specification is a value at 25°C.

[0034] The inclusion of onium ions as a filtration lubricant not only improves filtration efficiency but also interacts with the metal surface of semiconductor wafers, suppressing roughness of the metal surface after etching. While the mechanism is unclear, it is believed that onium ions adsorb to the metal surface of semiconductor wafers and inhibit etching of the metal surface by oxidizing agents. The etching rate of the metal of semiconductor wafers varies depending on factors such as crystal orientation, and this difference in etching rate can result in a loss of surface smoothness. When onium ions are added to the processing solution as a filtration lubricant, they selectively adsorb to crystal orientations that are easily etched, inhibiting etching of the adsorbed crystal orientations. As a result, the etching rate ratio for each crystal orientation approaches 1, presumably maintaining a smooth surface.

[0035] (Onium Ion) The surface tension is affected by the onium ion that may be contained in the semiconductor processing liquid of this embodiment as a filtration lubricant. Therefore, by appropriately selecting the type and concentration of the onium ion, it is possible to maintain the surface tension within an appropriate range. In order to maintain the surface tension within a preferred range, it is preferable to select one or more onium ions selected from the group consisting of onium ions represented by the following formulas (2) to (7).

[0036]

[0037] In formulas (2) to (7), R １ , R ２ , R ３ , R ４ , R ５ , R ６are independently an alkyl group having 2 to 9 carbon atoms, an allyl group, an aralkyl group having an alkyl group having 1 to 9 carbon atoms, or an aryl group. In addition, at least one hydrogen atom in the aryl group in the aralkyl group and in the ring of the aryl group may be replaced by fluorine, chlorine, an alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, or an alkenyloxy group having 2 to 9 carbon atoms, and in these groups, at least one hydrogen atom may be replaced by fluorine, chlorine, bromine, or iodine.

[0038] Counter anions for the onium ions include fluoride, chloride, bromide, iodide, hydroxide, nitrate, phosphate, sulfate, hydrogen sulfate, methanesulfate, perchlorate, chlorate, chlorite, hypochlorite, orthoperiodate, metaperiodate, iodate, iodite, hypoiodite, acetate, carbonate, hydrogen carbonate, fluoroborate, and trifluoroacetate. A is an ammonium ion or a phosphonium ion. Z is an aromatic group or alicyclic group which may contain nitrogen, sulfur, or oxygen atoms, and in the aromatic group or alicyclic group, carbon or nitrogen may have chlorine, bromine, fluorine, iodine, at least one alkyl group having 1 to 9 carbon atoms, at least one alkenyloxy group having 2 to 9 carbon atoms, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms. R is chlorine, bromine, fluorine, iodine, an alkyl group having 1 to 9 carbon atoms, an allyl group, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms. n is an integer of 1 or 2 and indicates the number of R. When n is 2, R may be the same or different and may form a ring. a is an integer of 1 to 10.

[0039] The longer the hydrocarbon group represented by R in the formula, the more hydrophobic it becomes. Therefore, the longer the chain of the onium ion containing the hydrocarbon group, the lower the surface tension of the semiconductor processing solution tends to be. On the other hand, if the hydrocarbon chain is too short, the effects of the onium ion, such as improving the surface smoothness and the RuO ４ For this reason, it is preferable that the number of carbon atoms in the hydrocarbon group is within the above range.

[0040] The concentration of onium ions in the semiconductor processing solution of this embodiment is preferably 1 mass ppm or more and 10,000 mass ppm or less. If the amount of onium ions added is too small, RuO ４ － The interaction with RuO ４ Not only does the gas suppression effect decrease, but the amount of onium ions adhering to the metal surface during etching becomes insufficient, which tends to reduce surface smoothness. On the other hand, if the amount added is too large, the amount of onium ions adsorbed to the metal surface becomes excessive, resulting in a decrease in the etching rate. Furthermore, when an oxidizing agent is contained in the semiconductor processing solution, the reaction between the oxidizing agent and the onium ions may cause a decrease in the concentration of the oxidizing agent. Therefore, the semiconductor processing solution of this embodiment preferably contains onium ions in an amount of 1 mass ppm to 10,000 mass ppm, more preferably 10 mass ppm to 5,000 mass ppm, and even more preferably 50 mass ppm to 2,000 mass ppm. When onium ions are added, only one type may be added, or two or more types may be added in combination. Even when two or more types of onium ions are contained, as long as the total concentration of the onium ions is within the above concentration range, RuO ４ Gas generation can be effectively suppressed.

[0041] Examples of such onium ions include chlorocholine ion, trans-2-butene-1,4-bis(triphenylphosphonium ion), 1-hexyl-3-methylimidazolium ion, allyltriphenylphosphonium ion, tetraphenylphosphonium ion, benzyltriphenylphosphonium ion, methyltriphenylphosphonium ion, (2-carboxyethyl)triphenylphosphonium ion, (3-carboxypropyl)triphenylphosphonium ion, (4-carboxybutyl)triphenylphosphonium ion, (5-carboxypentyl)triphenylphosphonium ion, cinnamyltriphenylphosphonium ion, (2-hydroxybenzyl)triphenylphosphonium ion, (1-naphthylmethyl)triphenylphosphonium ion, butyltriphenylphosphonium ion, (tert-butoxycarbonylmethyl)triphenylphosphonium ion, allyltriphenylphosphonium ion, (3-methoxybenzyl)triphenylphosphonium ion, (methoxymethyl)triphenylphosphonium ion, (1-ethoxy-1-methyl)triphenylphosphonium ion, (2,4-dichlorobenzyl)triphenylphosphonium ion, (2-hydroxy-5-methylphenyl)triphenylphosphonium ion, (4-chlorobenzyl)triphenylphosphonium ion, (3-chloro-2-hydroxypropyl)trimethylammonium ion, methacryloylcholine ion, benzoylcholine ion, benzyldimethylphenylammonium ion, (2-methoxyethoxymethyl)triethylammonium ion, carbamylcholine ion, 1,1'-difluoro-2,2'-bipyridinium bis(tetrafluoroborate), benzyltributylammonium ion, trimethylphenylammonium ion, 5-azoniaspiro[4.4]nonane ion, tributylmethylammonium ion, tetrabutylammonium ion, tetrapentylammonium ion, tetrabutylphosphonium ion, diallyldimethylammonium ion, 1,Examples thereof include 1-dimethylpiperidinium ion, (2-hydroxyethyl)dimethyl(3-sulfopropyl)ammonium hydroxide, 3-(trifluoromethyl)phenyltrimethylammonium ion, 1,1'-(decane-1,10-diyl)bis[4-aza-1-azoniabicyclo[2.2.2]octane]diion, (3-bromopropyl)trimethylammonium ion, vinylbenzyltrimethylammonium ion, allyltrimethylammonium ion, trimethylvinylammonium ion, choline ion, β-methylcholine ion, and triphenylsulfonium ion, and preferably benzyldimethylphenyl ion. and at least one selected from the group consisting of a phenylammonium ion, a 1-ethoxy-1-oxopropan-2-yl)triphenylphosphonium ion, a 1,1'-(decane-1,10-diyl)bis[4-aza-1-azoniabicyclo[2.2.2]octane]diion, a butyltriphenylphosphonium ion, a (2-carboxyethyl)triphenylphosphonium ion, a (3-carboxypropyl)triphenylphosphonium ion, a (4-carboxybutyl)triphenylphosphonium ion, an allyltriphenylphosphonium ion, a tetraphenylphosphonium ion, and a benzyltriphenylphosphonium ion.

[0042] (Method for Etching a Semiconductor Wafer) The semiconductor treatment solution of this embodiment can be used in a method for etching a semiconductor wafer. The etching method includes a step of contacting a semiconductor wafer with the semiconductor treatment solution of this embodiment. When the semiconductor treatment solution of this embodiment contains the filtration lubricant described above, it can be preferably used as an etching solution for semiconductor wafers. The conditions for the filtration lubricant are the same as those described above. As an example of an etching method performed using the treatment solution of this embodiment, a wet etching method for ruthenium will be described. First, a substrate made of a semiconductor (e.g., Si) is prepared. The prepared substrate is subjected to an oxidation treatment to form a silicon oxide film on the substrate. Thereafter, an interlayer insulating film made of a low dielectric constant (Low-k) film is formed, and via holes are formed at predetermined intervals. After the via holes are formed, a ruthenium film is formed by thermal CVD. This ruthenium film is etched using the semiconductor treatment solution of this embodiment to form RuO ４ It is possible to form ruthenium wiring with excellent surface smoothness in a via hole while suppressing gas generation. The metal contained in the semiconductor wafer can be at least one metal selected from Ru, Rh, Ti, Ta, Co, Cr, Hf, Os, Pt, Ni, Mn, Cu, Zr, La, Mo, and W. Among these, ruthenium is not limited to metallic ruthenium, and may contain 70 atomic % or more of ruthenium. It also includes ruthenium alloys, ruthenium oxides (ruthenium dioxide, ruthenium trioxide, etc.), nitrides, oxynitrides, intermetallic compounds, ionic compounds, complexes, etc. The temperature when etching a metal such as ruthenium (specific examples will be described later) using the semiconductor treatment solution of this embodiment is not particularly limited, but may be determined taking into consideration the etching rate of the metal such as ruthenium. If the treatment temperature is high, for example, when etching ruthenium, RuO ４The amount of gas increases, and the stability of the halogen oxyacid also decreases. On the other hand, the etching rate tends to decrease as the temperature decreases. For these reasons, the temperature for etching metals such as ruthenium is preferably 10°C to 90°C, more preferably 15°C to 60°C, and most preferably 25°C to 45°C. When the semiconductor processing solution of this embodiment contains a filtration lubricant, the surface tension at 25°C is preferably 60 mN / m or more and 75 mN / m or less.

[0043] (Method for manufacturing semiconductor devices) The method for manufacturing semiconductor devices of this embodiment includes a step of etching a semiconductor wafer using the semiconductor processing liquid described above. The filtration lubricant described above may be added to the semiconductor processing liquid of this embodiment. When the semiconductor processing liquid of this embodiment includes the filtration lubricant, the method for manufacturing semiconductor devices may include a filtration step. The conditions described above can be applied to the etching step as they are. The metal to be etched can also be the same as above. To etch a semiconductor wafer, the semiconductor processing liquid preferably includes the oxidizing agent described above. The conditions described above can be applied to the type of oxidizing agent and the concentration of the oxidizing agent in the semiconductor processing liquid. When the semiconductor processing liquid includes the filtration lubricant, the surface tension of the semiconductor processing liquid at 25°C is 60 mN / m or more and 75 mN / m or less, the preferred range being the same as the conditions described above.

[0044] Referring to FIG. 1 , if a filtration process is included in the manufacturing of semiconductor devices, the semiconductor processing solution may pass through filters 1 and 2 or 3. When valve 10 in FIG. 1 is closed and valve 9 is opened, the chemical solution in chemical cabinet 6 is filtered by passing through filters 1 and 2 by driving pump 4. To remove as many impurities as possible from the chemical solution in chemical cabinet 6, the filtration process of passing the chemical solution through filters 1 and 2 may be performed multiple times. The number of filters passed during each filtration process may be, for example, one or more, such as two, three, or four or more. When valve 10 in FIG. 1 is opened, the chemical solution in chemical cabinet 6 is supplied to etching table 8 by driving pump 4, where semiconductor wafers are etched. Furthermore, to replenish the chemical solution in chemical cabinet 6, the chemical solution in the chemical solution replenishment unit is passed through filter 3 by driving pump 5 and replenished into chemical cabinet 6. Note that the chemical solution described here may be the semiconductor processing solution itself, or a chemical solution to which a filtration lubricant has been added. Whether or not a filtration lubricant is included, the preferred surface tension range of the semiconductor processing liquid is the same as the range described above. The semiconductor device manufacturing method may include known processes used in semiconductor device manufacturing, such as one or more processes selected from a wafer fabrication process, an oxide film formation process, a transistor formation process, a wiring formation process, and a CMP process. The semiconductor device manufacturing method of this embodiment may also use the used semiconductor processing liquid described above. Specifically, the semiconductor device manufacturing method of this embodiment may include a process of recovering the semiconductor processing liquid after etching the semiconductor wafer, and a process of etching the semiconductor wafer using the recovered processing liquid. The semiconductor device manufacturing method of this embodiment may also include a process of measuring the concentration of an oxidizing agent in the recovered processing liquid.

[0045] (RuO ４ Gas Generation Suppression Method) The following description will be given taking as an example a case where the object to which the treatment solution of this embodiment is applied contains a transition metal, particularly ruthenium. As described above, the decomposition suppressant of this embodiment is RuO ４ is reduced to RuO４ It also has the effect of suppressing the generation of gas. ４ As a gas generation inhibitor, a treatment method including a step of adding the inhibitor to a ruthenium treatment solution can be mentioned. Specifically, for example, by adding the decomposition inhibitor of this embodiment to a ruthenium treatment solution used in an etching step, a residue removal step, a cleaning step, a CMP step, etc. in a semiconductor manufacturing process, RuO ４ Furthermore, when cleaning ruthenium adhering to the inner walls of the chambers, piping, etc. in the various devices used in these semiconductor manufacturing processes, the decomposition inhibitor of this embodiment can be used to prevent the generation of RuO ４ For example, in the maintenance of equipment that forms Ru using physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), or the like, by adding the decomposition inhibitor to a cleaning solution used to remove Ru adhering to a chamber, piping, or the like, the generation of RuO gases that is generated during cleaning can be suppressed. ４ According to this method, the RuO gas can be suppressed by the above-mentioned mechanism. ４ For example, when the decomposition inhibitor of the present invention is used in the ruthenium wiring formation process, the following occurs: A ruthenium film prepared by the procedure explained in the above section on the semiconductor wafer etching method is etched with a semiconductor processing solution to which the decomposition inhibitor is added, thereby suppressing the generation of RuO ４ This allows planarization while suppressing gas generation. ２ The decomposition inhibitor can be added to a semiconductor processing solution containing the ruthenium compound, and the semiconductor processing solution can be used to remove ruthenium adhering to the bevel of a semiconductor wafer.

[0046] The decomposition inhibitor of this embodiment can suppress the decomposition of RuO2 not only when added to a treatment solution for treating an object containing ruthenium, but also when added to a solution after treating an object containing ruthenium (hereinafter referred to as a ruthenium-containing solution). ４The ruthenium-containing liquid is a liquid containing ruthenium even in a small amount. The ruthenium contained in the ruthenium-containing liquid is not limited to metal ruthenium, but may be any liquid containing ruthenium element, such as Ru, RuO, etc. ４ ― , RuO ４ ２― , RuO ４ , RuO ２ Examples of the ruthenium-containing liquid include the waste liquid generated in the semiconductor manufacturing process and chamber cleaning, and RuO ４ Examples include the treatment liquid in exhaust gas treatment equipment (scrubber) that captures gas. If even a trace amount of ruthenium is contained in the ruthenium-containing liquid, RuO ４ RuO via gas ２ The particles generated contaminate tanks and piping, and the oxidation of the particles accelerates the deterioration of equipment. ４ The gas is highly toxic to the human body even at low concentrations. Ruthenium-containing liquids have various adverse effects on equipment and the human body. ４ It is necessary to treat the ruthenium-containing solution safely and quickly while suppressing the generation of gas. ４ This not only suppresses gas generation, allowing for safe disposal of ruthenium-containing liquid, but also reduces contamination and deterioration of the equipment's tanks and piping.

[0047] When the decomposition inhibitor of this embodiment is added to a ruthenium treatment solution or a ruthenium-containing solution, the concentration of the decomposition inhibitor of this embodiment is preferably adjusted to 0.0001 to 50 mass%. The ruthenium treatment solution and the ruthenium-containing solution may contain the transition metal oxidizer described above. Examples of the transition metal oxidizer include those described above. The concentration range of the transition metal oxidizer also includes the range described above. The amount of the decomposition inhibitor of this embodiment added to the ruthenium treatment solution or the ruthenium-containing solution may be determined taking into account the amount of ruthenium present in these solutions. The amount of the decomposition inhibitor of this embodiment added is not particularly limited, but is preferably 1 to 500,000 by weight, more preferably 10 to 100,000, and even more preferably 100 to 10,000, when the amount of ruthenium present in the ruthenium treatment solution or the ruthenium-containing solution is taken as 1. Furthermore, the pH at 25° C. of the ruthenium treatment solution or ruthenium-containing solution containing the decomposition inhibitor of this embodiment is preferably, for example, 7 to 14. In order to adjust the pH of this mixed solution, the pH adjuster exemplified above may be added.

[0048] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0049] (Preparation of Tetramethylammonium Hypochlorite Solution) 209 g of a 25% by mass aqueous solution of tetramethylammonium hydroxide and 791 g of ultrapure water were mixed in a 2 L three-necked glass flask (manufactured by Cosmos Bead Co., Ltd.), and the mixture was heated with CO ２ A 5.2% by mass aqueous solution of tetramethylammonium hydroxide was obtained, with a content of 0.5 ppm and a pH of 13.8.

[0050] Next, a rotor (manufactured by AsOne, total length 30 mm x diameter 8 mm) was placed in a three-neck flask, a thermometer protection tube (manufactured by Cosmos Bead, bottom-sealed type) and a thermometer were placed in one opening, a chlorine gas cylinder and a nitrogen gas cylinder were connected to the other opening, and the tip of a PFA tube (manufactured by Flon Industries Co., Ltd., F-8011-02) that was connected to a state in which chlorine gas / nitrogen gas could be switched at will was immersed in the bottom of the solution, and the remaining opening was connected to a gas washing bottle (manufactured by AsOne, gas washing bottle, model number 2450 / 500) filled with a 5% by mass aqueous solution of sodium hydroxide. Next, nitrogen gas with a carbon dioxide concentration of less than 1 ppm was poured from the PFA tube at a concentration of 0.289 Pa m ３ / second (at 0°C) for 20 minutes to expel carbon dioxide from the gas phase. At this time, the carbon dioxide concentration in the gas phase was 1 ppm or less.

[0051] Thereafter, a magnetic stirrer (C-MAG HS10, manufactured by AsOne) was placed at the bottom of the three-necked flask and rotated at 300 rpm to stir the contents. While the outer periphery of the three-necked flask was cooled with ice water, chlorine gas (manufactured by Fujiox Co., Ltd., specified purity 99.4%) was introduced at a concentration of 0.059 Pa m ３ / sec (at 0°C) for 180 minutes to obtain a mixed solution of tetramethylammonium hypochlorite aqueous solution (hypochlorite ions; equivalent to 3.51% by mass, 0.28 mol / L) and tetramethylammonium hydroxide (equivalent to 0.09% by mass, 0.0097 mol / L). The liquid temperature during the reaction was 11°C.

[0052] (Preparation of Treatment Solution) A decomposition inhibitor represented by formula (1), a solution containing halogen oxygen acid ions, ultrapure water, and a pH adjuster were mixed in predetermined amounts to obtain treatment solutions having the compositions shown in Tables 1 to 3.

[0053] (Production of treatment liquid containing filtration lubricant) A decomposition inhibitor represented by formula (1), a solution containing halogen oxygen acid ions, ultrapure water, a pH adjuster, and a filtration lubricant represented by formulas (2) to (7) were mixed in predetermined amounts to obtain a treatment liquid having the composition shown in Table 4.

[0054] (Halogen Oxygen Acid Ions in the Treatment Solution) When hypochlorite ions are selected as the halogen oxygen acid ions, the tetramethylammonium hypochlorite solution obtained by the above operation is used at a predetermined concentration as a solution containing halogen oxygen acid ions. When hypobromite ions or hypobromite ions and hypochlorite ions are selected as the halogen oxygen acid ions, a predetermined amount of tetramethylammonium bromide (97% by mass, manufactured by Tokyo Chemical Industry Co., Ltd.) is added to the tetramethylammonium hypochlorite solution obtained by the above operation, and the solution is used at a predetermined concentration as a solution containing halogen oxygen acid ions. When periodate ions are selected as the halogen oxygen acid ions, a solution containing orthoperiodate ions is used at a predetermined concentration as a solution containing halogen oxygen acid ions.

[0055] (Method for calculating hypobromite ion and hypochlorite ion concentrations) The hypobromite ion and hypochlorite ion concentrations were measured using an ultraviolet-visible spectrophotometer (V-700, manufactured by JASCO Corporation). A calibration curve was created using aqueous solutions of hypobromite ion and hypochlorite ion with known concentrations, and the hypobromite ion and hypochlorite ion concentrations in the produced filtration lubricant were determined. The hypobromite ion concentration was determined from the measurement data when the absorption spectrum stabilized after mixing the bromine-containing compound, oxidizing agent, and base compound.

[0056] (Method for Calculating Periodate Ion Concentration) The periodate ion concentration was measured by titration. After preparing the treatment solutions of the Examples and Comparative Examples, 0.5 mL of the treatment solution, 2 g of potassium iodide (Wako Pure Chemical Industries, Ltd., special grade reagent), 8 mL of 10% acetic acid, and 10 mL of ultrapure water were added to a 100 mL Erlenmeyer flask and stirred until the solids dissolved, yielding a brown solution. The prepared brown solution was subjected to oxidation-reduction titration using 0.01 M sodium thiosulfate solution (Wako Pure Chemical Industries, Ltd., for volumetric analysis) until the solution color changed from brown to very light yellow. Starch solution was then added to obtain a pale purple solution. Further 0.01 M sodium thiosulfate solution was added to this solution, and the periodate concentration was calculated from the point at which the solution became colorless and transparent.

[0057] (Evaluation) The stability of the oxidant concentration relative to the transition metal oxidant was evaluated using the treatment solution produced by the method described above. ４ The gas generation suppression effect was evaluated. In addition, the stability of the oxidizing agent concentration relative to the transition metal oxidant when the filtration lubricant was added, the surface tension, the onium salt residual rate after filtration, and the surface smoothness after etching were also evaluated.

[0058] Examples 1 to 25, Comparative Examples 1 to 9 (Evaluation of Stability of Transition Metal Oxidizers Against Transition Metal Oxidants) 0.05% by mass of hypochlorite ions, 0.1% by mass of hypobromite ions, or both, obtained by the method described above, were used as the transition metal oxidizer. A treatment solution containing a predetermined concentration of a decomposition inhibitor in the transition metal oxidizer was prepared, and a predetermined amount of commercially available tetrapropylammonium perruthenate (TPAP, manufactured by Tokyo Chemical Industry Co., Ltd.) was further added relative to the total mass of the treatment solution. The presence of the predetermined oxidizer concentration was then confirmed using a UV-visible spectrophotometer, and the oxidizer concentration before storage was obtained. After storage in a 40°C thermostatic chamber for one day, the oxidizer concentration was measured again, and the residual rate of the transition metal oxidizer concentration before and after storage was evaluated and listed in Table 1. The residual rate of the oxidizer concentration was graded A to D in descending order, with grades A to C being acceptable levels and grade D being unacceptable levels. A: 90% or more B: 75% or more but less than 90% C: 60% or more but less than 75% (acceptable level) D: Less than 60%

[0059] Examples 26-28, Comparative Example 10: A 3% aqueous orthoperiodic acid solution was prepared using orthoperiodate (manufactured by Tokyo Chemical Industry Co., Ltd.) as a transition metal oxidizing agent and a pH adjuster. A treatment solution containing a predetermined concentration of decomposition inhibitor in the transition metal oxidizing agent was prepared, and a predetermined amount of commercially available tetrapropylammonium perruthenate (TPAP, manufactured by Tokyo Chemical Industry Co., Ltd.) was further added relative to the total mass of the treatment solution. The presence of the oxidizing agent at the predetermined concentration was then confirmed using a titration method, and the oxidizing agent concentration before storage was obtained. After storage in a 40°C thermostatic chamber for one day, the oxidizing agent concentration was measured again, and the residual rate of the transition metal oxidizing agent concentration before and after storage was evaluated and reported in Table 2. As in Examples 1-19 and Comparative Examples 1-9, the residual rate of the oxidizing agent concentration was ranked A to D in descending order, with A to C being acceptable levels and D being unacceptable levels. A: 90% or more B: 75% or more but less than 90% C: 60% or more but less than 75% (acceptable level) D: Less than 60%

[0060]

[0061]

[0062] Comparing Examples 1, 6 to 16 with Comparative Example 1, it can be seen that the addition of the compound represented by formula (1), i.e., the decomposition inhibitor, significantly increased the residual rate of the oxidizing agent. Furthermore, Comparative Examples 2 to 7 added additives described in prior art documents, but it was confirmed that they had no decomposition inhibitor effect compared to Example 1. The concentration of the decomposition inhibitor was varied in Examples 1 to 5, and it was confirmed that a sufficient effect could be obtained even with the addition of 10 ppm. It was also confirmed that the residual rate of the oxidizing agent tended to decrease with the addition of 10,000 ppm or more.

[0063] Comparing Examples 1, 17 to 28 with Comparative Examples 1, 8 to 10, it was confirmed that as long as the oxidizing agent is one or more halogen oxygen acid ions selected from the group consisting of hypobromite ions, hypochlorite ions, and periodate ions, a decomposition suppression effect can be obtained when a decomposition suppressor is added, as in Examples 1 to 16. Furthermore, comparing Example 1 with Example 17, it was confirmed that an oxidizing agent contained in the treatment solution that is a mixture of hypobromite ions and hypochlorite ions is more effective than hypobromite ions alone.

[0064] Comparing Examples 1 and 14 to 16, it was confirmed that, among the compounds having a structure represented by formula (1), the compound having an aromatic group as in Example 1 has a high effect, and is more effective than the compound having a group having a carbon-carbon double bond and the compound having a group having a carbon-carbon triple bond.

[0065] Comparing Examples 9 to 11, Example 11 has low water solubility because the electron donating group is an ethoxy group, and even if the amount added is increased, separation into two phases occurs, resulting in less effective results than Example 9. In Examples 7 and 8, the decomposition inhibitor is a compound having no hydrophilic group, so has low water solubility and even if the amount added is increased, separation into two phases occurs, confirming that it is less effective than Example 1.

[0066] <Examples 29 to 34, Comparative Examples 11 to 15> (RuO ４ Evaluation of gas generation suppression effect) RuO ４ The amount of gas generated was measured using ICP-OES. 5 mL of the mixture was placed in a sealed container, and a 10 x 20 mm Si wafer with a 1200 Å thick ruthenium film was immersed in it at 35°C until all of the ruthenium dissolved. Air was then flowed into the sealed container, and the gas phase in the sealed container was bubbled into a container containing an absorbing solution (1 mol / L NaOH). The RuO generated during the wafer immersion was measured. ４ The gas was trapped in the absorption liquid. The amount of ruthenium in the absorption liquid was measured by ICP-OES. ４ The amount of Ru in the gas was evaluated and is shown in Table 3. ４ The amount of Ru in the gas is the value obtained by dividing the total mass of ruthenium contained in the absorption solution by the area of ​​the immersed wafer. The complete dissolution of ruthenium on the Si wafer immersed in the mixed solution was confirmed by measuring the sheet resistance before and after immersion using a four-point probe resistance meter (Loresta-GP, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) and converting it into film thickness. The evaluation criteria are A to B, with evaluation A being an acceptable level and evaluation B being an unacceptable level. A: 1 μg / cm ２ Less than (acceptable level) B: 1 μg / cm ２ End

[0067]

[0068] Comparing Examples 29 and 33 with Comparative Example 11, it is clear that the addition of the compound represented by formula (1) increased the amount of RuO ４ The amount of Ru released as gas is 1 μg / cm ２ Furthermore, when Examples 29 to 32 are compared with Comparative Examples 11 to 14, it is clear that when the oxidizing agent is at least one halogen oxygen acid ion selected from the group consisting of hypobromite ion, hypochlorite ion, and periodate ion, RuO ４ It was confirmed that the gas release suppression effect was obtained.

[0069] Examples 35 to 43 and Reference Examples 1 to 3 (Production of Treatment Liquids Before and After Addition of Filtration Lubricant) Example 35 is a treatment liquid in which the concentration of the decomposition inhibitor contained in Example 17 was adjusted to 5000 ppm, and this treatment liquid was used as a treatment liquid before the addition of a filtration lubricant. In addition, in Examples 36 to 43 and Reference Examples 1 to 3, each filtration lubricant shown in Table 4 was added to the treatment liquid before the addition of the filtration lubricant to prepare a treatment liquid after the addition of the filtration lubricant.

[0070] (Evaluation of Surface Tension) The treatment liquid was measured before and after the addition of the filtration lubricant using a surface tensiometer (DY300, manufactured by Kyowa Interface Science Co., Ltd.) in accordance with JIS 2241 "Test method using a Wilhelmy surface tensiometer."

[0071] (Filtration of filtration lubricant) 2 L of treatment liquid containing a filtration lubricant was filled into a 5 L PFA bottle, and using a diaphragm-type liquid transfer pump (NF100TT 18S, manufactured by KNF Corporation), the liquid was passed through a filter with a filtration accuracy of 5 nm (SWD03UG54E71-K13C, manufactured by Nippon Pall Corporation). The solution that passed through the filter was recovered in the original PFA bottle, and the recovered treatment liquid was passed through the filter. This operation was repeated, and filter filtration was repeated until the entire 2 L of solution had passed through the filter 100 times. The resulting solution was recovered as a treatment liquid containing a filtered filtration lubricant.

[0072] (Evaluation of Onium Ion Remaining Rate After Filtration) The onium ion concentrations in the treatment solution containing the filtration lubricant before and after filtration were evaluated using a liquid chromatography mass spectrometer (Xevo QTof MS, manufactured by Waters Corporation), and the onium ion remaining rate after filtration was evaluated according to the following criteria. In all cases, ratings A to C are acceptable levels, and rating D is an unacceptable level. A: 95% or more B: 80% or more but less than 95% C: 60% or more but less than 80% (acceptable level) D: Less than 60%

[0073] (Evaluation of surface smoothness after etching) The ruthenium surface was observed before and after etching using a field emission scanning electron microscope (JSM-7800F Prime, manufactured by JEOL Ltd.) to check for the presence or absence of surface roughness, and was evaluated according to the following criteria. Surface roughness was ranked from least to greatest, A to D, with ratings A to C being acceptable levels and rating D being unacceptable. A: No surface roughness was observed B: Some surface roughness was observed C: Roughness was observed over the entire surface, but the roughness was shallow D: Roughness was observed over the entire surface, and the roughness was deep

[0074]

[0075] A comparison of the residual oxidizing agent rates in Examples 35 to 43 and Reference Examples 1 to 3 revealed that the addition of the compounds represented by formulas (2) to (7) resulted in a higher residual oxidizing agent rate. Although the mechanism is not clear, it is believed that this is because the onium ions, which are cations, form ion pairs with the transition metal oxidants, which are anions, changing the reactivity of the transition metal oxidants, making them more susceptible to reaction with the decomposition inhibitor than with the oxidizing agent contained in the treatment solution.

[0076] Next, Examples 35 to 43 and Reference Examples 1 to 3 are compared in terms of surface tension, onium ion residual rate after filtration, and surface smoothness after etching. In Examples 35 to 43, the surface tension was almost the same as before the addition of the filtration lubricant, so the onium ion residual rate did not change even after filtration. Furthermore, the high onium ion residual rate after filtration improved the surface smoothness. In Reference Examples 1 to 3, the surface tension was low, so the onium ions were removed during the filtration process. Therefore, the surface smoothness did not improve.

[0077] 1 Filter 1 2 Filter 2 3 Filter 3 4 Pump 4 5 Pump 5 6 Chemical cabinet 7 Chemical liquid replenishment unit 8 Etching table 9 Valve 9 10 Valve 10

Claims

1. A decomposition inhibitor for a transition metal oxidizing agent, A decomposition inhibitor comprising a compound represented by the following formula (1), wherein A in the following formula (1) has a hydrophilic group in addition to X: A-(X) ｎ (1) A: an aromatic group, a group having a carbon-carbon double bond, or a group having a carbon-carbon triple bond X: electron donating group n: integer

2. 2. The decomposition inhibitor according to claim 1, wherein in said formula (1), A is an aromatic group and n is 1 or 2.

3. 3. The decomposition inhibitor according to claim 1, wherein in the formula (1), X is an amino group or an alkoxy group.

4. (delete)

5. The decomposition inhibitor according to claim 1 , wherein the hydrophilic group is a carboxyl group.

6. The decomposition inhibitor according to any one of claims 1 to 3 and 5, which is added to a semiconductor processing solution and used for reusing the semiconductor processing solution.

7. The decomposition inhibitor according to any one of claims 1 to 3, 5, and 6, wherein the transition metal comprises at least one metal selected from the group consisting of Ru, Rh, Ti, Ta, Co, Cr, Hf, Os, Pt, Ni, Mn, Cu, Zr, La, Mo, and W.

8. The decomposition inhibitor for an oxidizing agent for a transition metal according to any one of claims 1 to 3 and 5 to 7, wherein the transition metal is Ru.

9. A semiconductor processing solution comprising the decomposition inhibitor for a transition metal oxidizing agent according to any one of claims 1 to 3 and 5 to 8, and an oxidizing agent for a transition metal.

10. 10. The semiconductor processing solution according to claim 9, wherein the concentration of the decomposition inhibitor is 1 ppm by mass or more and 10,000 ppm by mass or less, based on the total mass of the semiconductor processing solution.

11. 11. The semiconductor processing solution according to claim 9, wherein the transition metal oxidizing agent is at least one halogen oxygen acid ion selected from the group consisting of a hypobromite ion, a hypochlorite ion, and a periodate ion, and the total concentration of all the transition metal oxidizing agents is 50 ppm by mass or more and 35% by mass or less, based on the total mass of the semiconductor processing solution.

12. 12. The semiconductor processing solution according to claim 11, wherein the oxidizing agent for transition metals is a hypobromite ion and a hypochlorite ion.

13. The semiconductor processing solution according to any one of claims 9 to 12, further comprising a transition metal oxidant.

14. The semiconductor processing solution according to any one of claims 9 to 13, further comprising a filtration lubricant.

15. 15. The semiconductor processing solution according to claim 14, wherein the filter lubricant is an onium ion.

16. A method for etching a semiconductor wafer, comprising contacting a semiconductor wafer containing a transition metal with the semiconductor processing solution according to any one of claims 9 to 15, and etching the transition metal.

17. A method for manufacturing a semiconductor device, comprising the etching method according to claim 16 in a process.