Method, system, and method for manufacturing impurity elements in a metal sample.

Abstract

This enables a more sensitive method for analyzing impurity elements in metal samples than conventional methods. [Solution] The method for analyzing impurity elements in a metal sample according to this disclosure includes the following steps A to C: Step A, in which an anion exchange resin is brought into contact with solution A two or more times; Step B, in which an analysis solution is obtained using the anion exchange resin obtained through step A; and Step C, in which impurity elements in the metal sample are analyzed using the analysis solution.

Description

Technical Field

[0001] The present invention relates to a method for analyzing impurity elements in a metal film, an analysis system, and a method for manufacturing a column.

Background Art

[0002] During the manufacture of semiconductors, various metal films are used as insulating films for preventing leakage current, barrier metals for preventing metal diffusion and chemical reactions in the wiring process, or low-resistance electrode materials. If such a metal film contains impurities, performance defects may occur in the semiconductor. In particular, in recent years, as semiconductor miniaturization and microminiaturization have advanced, even trace amounts of impurities can affect semiconductor performance. Therefore, there has been a demand for a method for more sensitively quantifying impurity elements contained in metal films.

[0003] For example, Patent Document 1 discloses a method of dissolving a thin film using an acid and quantifying impurity elements in the obtained solution. Since the solution contains a large amount of the metal constituting the metal film, in order to solve the problem that it is difficult to highly sensitively quantify impurity elements, a method of removing the metal constituting the metal film using an anion exchange resin and then analyzing is disclosed. <000​​​​​​​​​​​​​​​​​​​​​​Japanese Patent Publication No. 2014-36924 [Patent Document 4] Japanese Patent Publication No. 2007-117781 [Non-patent literature]

[0006] [Non-Patent Document 1] Chemistry Education (1968), Vol. 16, No. 3, p. 231 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, the cleaning methods described in Patent Documents 2-4 and Non-Patent Document 1 had room for improvement in terms of the amount of impurity elements remaining in the anion exchange resin.

[0008] In consideration of the above problems, the inventors have found an analytical method that can simultaneously and sensitively quantify a wide range of impurity elements contained in a metal sample by reducing the amount of impurity elements eluted from the anion exchange resin compared to conventional methods.

[0009] One aspect of the present invention aims to realize a method for analyzing impurity elements in metal samples with higher sensitivity than conventional methods. [Means for solving the problem]

[0010] To solve the above problems, a method for analyzing impurity elements in a metal sample according to one aspect of the present invention includes the following steps A to C: Step A: A step of contacting an anion exchange resin with a solution A containing two or more types of mineral acids two or more times; Step B: A step of obtaining an analytical solution from the metal sample solution using the anion exchange resin obtained through Step A; Step C: A step of analyzing impurity elements in the metal sample using the analytical solution.

[0011] A method for pre-treating an anion exchange resin according to one aspect of the present invention includes the following step A: Step A: A step of contacting an anion exchange resin with a solution A containing two or more types of mineral acids two or more times.

[0012] The anion exchange resin according to one aspect of the present invention is an anion exchange resin for analyzing impurity elements in a metal sample, wherein the amount of each impurity element eluted from the anion exchange resin is measured by inductively coupled plasma mass spectrometry and is less than 200 pg per 1 mL of the anion exchange resin.

[0013] The method for manufacturing a column according to one aspect of the present invention is a method for manufacturing a column for separating a target element and a non-target element from a dissolution solution of a metal sample, and includes the following steps A and D: Step A: A step of bringing an anion exchange resin into contact with a solution A containing two or more types of mineral acids two or more times; Step D: A step of filling the anion exchange resin that has undergone Step A into a column tube.

Advantages of the Invention

[0014] According to one aspect of the present invention, it is possible to realize an analytical method for impurity elements in a metal sample with higher sensitivity than conventional methods.

Brief Description of the Drawings

[0015] [Figure 1] It is a diagram showing an example of the structure of a pretreatment system according to an embodiment of the present invention. [Figure 2] It is a diagram showing an example of the structure of an analysis system according to an embodiment of the present invention. [Figure 3] It is a diagram showing an example of the structure of an analysis system according to another embodiment of the present invention.

Modes for Carrying Out the Invention

[0016] 〔1. Analytical Method for Impurity Elements in Metal Samples〕 The analytical method for impurity elements in a metal sample according to an embodiment of the present invention (hereinafter also referred to as the present analytical method) includes the following steps A to C: Step A: A step of bringing an anion exchange resin into contact with a solution A containing two or more types of mineral acids two or more times; Step B: A step of obtaining an analysis solution from the dissolution solution of the metal sample using the anion exchange resin that has undergone Step A; Process C: A process of analyzing impurity elements in a metal sample using an analytical solution.

[0017] By contacting a solution A containing a plurality of mineral acids with an anion exchange resin two or more times, a wide variety of impurity elements can be removed. Therefore, by including the above Process A in this analytical method, the amount of impurity elements eluted from the anion exchange resin can be made less than before. Specifically, various impurity elements can be reduced to less than 200 pg per 1 mL of the anion exchange resin. Therefore, according to this analytical method, it becomes possible to more accurately quantify the amount of impurity elements contained in a metal sample.

[0018] As the anion exchange resin, resins having a strongly basic group such as a quaternary ammonium group like a trimethylammonium group or a quaternary alkylalkanolamine group like a dimethylethanolammonium group are preferred.

[0019] Also, the material of the anion exchange resin is not particularly limited as long as it does not elute impurity elements. For example, resins such as styrene-based, styrene-divinylbenzene-based, acrylic-based, and methacrylic-based resins can be mentioned. The shape of the anion exchange resin is not particularly limited, and it may be, for example, in the form of beads or a membrane. When using a bead-shaped anion exchange resin, when obtaining an analytical solution, it is preferable to fill a cylindrical column with the anion exchange resin and use it.

[0020] (Process A) Step A is a step in which an anion exchange resin is brought into contact with a solution A containing two or more types of mineral acids two or more times. The method of bringing solution A and the anion exchange resin into contact is not particularly limited, but examples include immersion and liquid flow. Step A may be a step in which the same operation is repeated two or more times, or a step in which two or more different operations are performed one or more times each. That is, Step A may be a step in which the anion exchange resin is immersed and washed with solution A two or more times, or a step in which the anion exchange resin is liquid-washed with solution A two or more times, or a step in which both immersion washing and liquid flow washing are performed one or more times. Furthermore, the order in which the operations are performed in Step A is not particularly limited. That is, in Step A, for example, immersion may be performed first and then liquid flow may be performed, or liquid flow may be performed first and then immersion.

[0021] Step A can reduce the amount of impurity elements leached from the anion exchange resin. Furthermore, Step A can simultaneously reduce a wider range of impurity elements and provides an analytical method for impurity elements that can be applied to various types of metal samples.

[0022] The solution A that is brought into contact with the anion exchange resin in step A contains two or more mineral acids, preferably three or more mineral acids. In other words, solution A can be said to be a mixed acid. By containing three or more mineral acids in solution A, the amount of impurity elements leached from the anion exchange resin can be further reduced.

[0023] In this specification, mineral acid refers to an acid also called an inorganic acid. Mineral acids are not particularly limited and may be either oxoacids or non-oxoacids. Specific examples of mineral acids include hydrofluoric acid, nitric acid, hydrochloric acid, sulfuric acid, perchloric acid, periodic acid, sulfurous acid, nitrite, and phosphoric acid. Among these, two or more mineral acids selected from hydrofluoric acid, nitric acid, hydrochloric acid, sulfuric acid, perchloric acid, and periodic acid are preferred.

[0024] The mineral acid contained in solution A preferably has a low content of impurity elements. The amount of each impurity element contained in the mineral acid in solution A is preferably less than 100 ppt, more preferably less than 10 ppt, even more preferably less than 5 ppt, and most preferably no impurity elements at all. In this specification, "no impurity elements" means that the content of each impurity element is below the detection limit when measured by inductively coupled plasma mass spectrometry. The impurity elements that may be contained in the mineral acid are not particularly limited, but may be, for example, the elements listed as impurity elements in metal samples later.

[0025] In step A, there may be only one type of solution A, or there may be two or more types. That is, step A may be a step in which two or more different solutions A with different compositions and / or concentrations are brought into contact with an anion exchange resin. As will be described later, the solution A used in step A1 will also be called solution A1, and the solution A used in step A2 will also be called solution A2.

[0026] In one embodiment, impurity elements that may be present in the metal sample are also referred to as target elements, meaning they are the elements to be detected. Conversely, the main component metal elements that make up the metal sample are also referred to as non-target elements, meaning they are not the elements to be detected.

[0027] This analytical method may include an equilibration step after step A to separate the target element from the non-target element. The equilibration step is also called conditioning. The equilibration step is not particularly limited, but can be performed by contacting an anion exchange resin with pure water or one or more mineral acids (e.g., hydrofluoric acid, nitric acid, hydrochloric acid, sulfuric acid, perchloric acid, and periodic acid). The concentration of the mineral acid used in the equilibration step can be appropriately selected to adsorb either the target element or the non-target element. The equilibration step of this analytical method enables accurate analysis even when various target elements contained in a metal sample are present at low concentrations.

[0028] <Process A1> Step A may include step A1, in which an anion exchange resin is immersed in solution A. In other words, step A1 can be described as a step of immersion washing of the anion exchange resin using solution A1. Step A1 can reduce the amount of impurity elements leached from the anion exchange resin. In step A1, the anion exchange resin may be pre-mixed with ultrapure water or the like to facilitate the penetration of solution A1 into the anion exchange resin.

[0029] In process A, process A1 may be repeated two or more times. When process A1 is repeated, the same solution A1 may be used, or different solutions may be used. Also, process A1 may be combined with process A2, which will be described later. Process A1 may be performed before process A2, after process A2, or both before and after process A2. That is, after performing process A1, process A2 may be performed, and then process A1 may be performed again.

[0030] In step A1, the amount of solution A1 is not particularly limited, but is preferably 1 BV (Bed Volume) or more, more preferably 2 BV or more, and even more preferably 3 BV or more, relative to the anion exchange resin. The amount of solution A1 is not particularly limited, but may be, for example, 5 BV or less. In one embodiment, the amount of solution A1 is preferably equal to or greater than the weight of the anion exchange resin, more preferably twice or more, and even more preferably three times or more. The amount of solution A1 may be five times or less the weight of the anion exchange resin. In this specification, the amount of resin is expressed in mL as BV.

[0031] The concentration of the mineral acid in solution A1 in step A1 is not particularly limited as long as the anion exchange resin does not dissolve, but is preferably 0.1M to 5M, more preferably 0.2M to 4M, and even more preferably 0.3M to 3M. The concentrations of the two or more mineral acids contained in solution A1 may be the same or different. The concentration of the mineral acid in solution A1 may be changed depending on the type of mineral acid. For example, in solution A1, the concentration of hydrofluoric acid may be 1M to 4M, the concentration of nitric acid may be 0.1M to 0.5M, and the concentration of hydrochloric acid may be 0.2M to 0.8M. In this specification, the concentration of mineral acid is described as the concentration in the solution. For example, "a mixed acid of 4M hydrofluoric acid, 0.5M nitric acid, and 0.8M hydrochloric acid" means that "the concentration of hydrofluoric acid in the solution is 4M, the concentration of nitric acid is 0.5M, and the concentration of hydrochloric acid is 0.8M," and does not mean "a mixture of 4M hydrofluoric acid, 0.5M nitric acid, and 0.8M hydrochloric acid."

[0032] The mineral acid contained in solution A1 preferably has a low content of impurity elements. The amount of each impurity element contained in the mineral acid in solution A1 is preferably less than 100 ppt, more preferably less than 10 ppt, even more preferably less than 5 ppt, and most preferably no impurity elements at all. The impurity elements that may be contained in the mineral acid are not particularly limited, but may be, for example, the elements listed as impurity elements in the metal sample described later.

[0033] The immersion time of the anion exchange resin in step A1 is not particularly limited, but may be, for example, 24 hours or more, 48 hours or more, 72 hours or more, etc. The upper limit of the immersion time is not particularly limited, but may be, for example, 1 year or less, as long as the anion exchange resin does not deteriorate.

[0034] In one embodiment, the anion exchange resin immersed in solution A1 may be shaken during step A1. By further shaking during immersion, the amount of impurity elements eluted from the anion exchange resin can be reduced in a shorter time. In another embodiment, the anion exchange resin may be immersed and washed during step A1 while applying ultrasonic waves.

[0035] <Process A2> Step A may include step A2 through which a solution A2 containing two or more mineral acids is passed through an anion exchange resin. In other words, step A2 can be said to be a step of washing the anion exchange resin by passing solution A2 through it. Step A2 may be performed by packing the anion exchange resin into, for example, a cylindrical column and passing solution A2 through it. The solution A2 passed through in step A2 may be the same as the solution A1 used in step A1, or it may be different. Furthermore, two or more different solutions A2 may be passed through in step A2. Step A2 can reduce the amount of impurity elements eluted from the anion exchange resin.

[0036] In process A, process A2 may be repeated two or more times. When process A2 is repeated, the same solution A2 may be used, or different solutions may be used, but it is preferable to use different solutions. Furthermore, process A2 may be performed before process A1, after process A1, or both before and after process A1. That is, after performing process A2, process A1 may be performed, and then process A2 may be performed again.

[0037] The mineral acids that may be contained in solution A2 include the mineral acids that may be contained in solution A. Solution A2 contains two or more types of mineral acids, preferably three or more types of mineral acids. In other words, solution A2 can be said to be a mixed acid. By containing three or more types of mineral acids in solution A2, the amount of impurity elements leached from the anion exchange resin can be further reduced.

[0038] The concentration of the mineral acid in solution A2 is not particularly limited; for example, it may be the same as in solution A1, or it may be a different concentration. Also, the concentrations of two or more mineral acids in solution A2 may be the same or different. The concentration of the mineral acid in solution A2 may be changed depending on the type of mineral acid. For example, in solution A2, the concentration of hydrofluoric acid may be 1M to 4M, the concentration of nitric acid may be 0.1M to 0.5M, and the concentration of hydrochloric acid may be 0.2M to 0.8M.

[0039] The mineral acid contained in solution A2 preferably has a low content of impurity elements. The amount of each impurity element contained in the mineral acid in solution A2 is preferably less than 100 ppt, more preferably less than 10 ppt, even more preferably less than 5 ppt, and most preferably no impurity elements at all. The impurity elements that may be contained in the mineral acid are not particularly limited, but may be, for example, the elements listed as impurity elements in the metal sample described later.

[0040] For example, when passing solution A2 through an anion exchange resin in step A2, the amount of solution A2 to be passed through is not particularly limited, but is preferably 10 BV or more, more preferably 20 BV or more, and even more preferably 30 BV or more relative to the anion exchange resin. The upper limit of the amount of solution A2 is not particularly limited, but may be, for example, 100 BV or less. In one embodiment, when passing the solution through in step A2, the total amount of solution A2 used should be 10 BV or more.

[0041] (Process B) Step B is a step in which an analytical solution is obtained from the metal sample solution using the anion exchange resin that has gone through step A. Step B separates the target element from the non-target element in the solution and provides an analytical solution for quantifying impurity elements.

[0042] The components constituting the metal sample are not particularly limited. The main component of the metal sample may be at least one metal element that can be adsorbed onto an anion exchange resin, selected from the group consisting of beryllium, boron, aluminum, phosphorus, scandium, titanium, vanadium, iron, cobalt, nickel, copper, zinc, gallium, germanium, arsenic, zirconium, niobium, molybdenum, technetium, ruthenium, palladium, silver, cadmium, indium, tin, antimony, tellurium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, mercury, thallium, bismuth, thorium, protactinium, uranium, etc. The main component of the metal sample may also be a metal compound such as an oxide of the aforementioned metal element.

[0043] The impurity elements in a metal sample are not particularly limited, as long as they are elements other than the element selected as the main component of the metal sample. For example, if the main component of the metal sample is hafnium, the impurity elements may include any element other than hafnium. Furthermore, the impurity elements may be elemental or compound elements. That is, the impurity elements may be elemental elements such as metals, or metal compounds such as metal oxides.

[0044] In one embodiment, the metal sample may be a metal film. In this specification, a metal film is not particularly limited, but for example, it refers to a thin film with a thickness of 0.1 to 1000 nm. The metal film may, for example, be a thin film present on a semiconductor substrate.

[0045] For dissolving metal samples, it is preferable to use an acidic solution, an alkaline solution, an oxidizing agent, or a mixture thereof as the decomposition solution. Examples of acidic solutions include mineral acids (hydrofluoric acid, nitric acid, hydrochloric acid, sulfuric acid, aqua regia (hydrochloric acid:nitric acid = 3:1)). Examples of oxidizing agents include hydrogen peroxide solution, and examples of alkaline solutions include ammonia water, tetramethylammonium hydroxide aqueous solution, and mixtures thereof. In one embodiment, the decomposition solution may be solution A as described above. When an alkaline solution is used as the decomposition solution, it is preferable to perform a treatment to make the solution acidic during analysis.

[0046] One method for dissolving a thin film on a semiconductor substrate using a decomposition solution is to supply the decomposition solution onto the thin film. The resulting solution is then collected in a container made of, for example, polytetrafluoroethylene (hereinafter referred to as Teflon: registered trademark).

[0047] The concentration and amount of the decomposition solution used are not particularly limited as long as the thin film can be dissolved. The mineral acid concentration of the decomposition solution may be, for example, 0.1 M to 20 M. Furthermore, the amount of decomposition solution used to dissolve the metal sample is preferably 100 μL to 50 mL, and more preferably 300 μL to 40 mL.

[0048] In step B, for example, an analytical solution may be obtained by passing the decomposition solution through a column packed with anion exchange resin. The amount of anion exchange resin packed into the column used in step B may be, for example, 1 to 5 mL. In this case, an analytical solution for quantifying impurity elements can be obtained by passing the decomposition solution through the column. If necessary, the solution obtained by passing one type of mineral acid or another solution containing two or more types of mineral acids (for example, solution A) through the column may be further mixed to make an analytical solution.

[0049] (Process C) Step C is a step in which impurity elements in a metal sample are analyzed using the analytical solution obtained in Step B. In other words, Step C can be said to be a step in which impurity elements in a metal sample are quantified. The method for analyzing impurity elements is not particularly limited, and examples include inductively coupled plasma mass spectrometry (the mass spectrometry section can be, for example, quadrupole type, multi-quadrupole type, double-focusing type, time-of-flight type, etc.), inductively coupled plasma atomic emission spectrometry, graphite furnace atomic absorption spectrometry, total reflection X-ray fluorescence spectrometry, and secondary ion mass spectrometry. Among these, inductively coupled plasma mass spectrometry is preferred. In one embodiment, the analytical solution obtained in Step B may be concentrated or dried before performing Step C.

[0050] [2. Anion exchange resin] An anion exchange resin according to one embodiment of the present invention is an anion exchange resin for analyzing impurity elements in a metal sample, wherein the amount of each impurity element eluted from the anion exchange resin is measured by inductively coupled plasma mass spectrometry and is less than 200 pg per 1 mL of the anion exchange resin. The impurity elements eluted from the anion exchange resin are not particularly limited, but may be, for example, the elements listed above as impurity elements in a metal sample. The anion exchange resin is as described in [1. Method for analyzing impurity elements in a metal sample]. The anion exchange resin can also be manufactured by [4. Method for manufacturing anion exchange resin] described later. Hereafter, "per 1 mL of anion exchange resin" will also be simply referred to as "per 1 mL of resin".

[0051] In this specification, "impurity elements in a metal sample" means elements that are present in the metal sample being analyzed and can be detected as impurities. "Amount of each impurity element leached from the anion exchange resin" refers to the amount of each different type of impurity element leached, not the total amount of impurity elements leached. Hereafter, "amount of each impurity element leached from the anion exchange resin" will also be simply referred to as "leaching amount of each impurity element."

[0052] The amount of each impurity element eluted from the anion exchange resin is less than 200 pg per 1 mL of resin, preferably less than 100 pg, more preferably less than 50 pg, even more preferably less than 20 pg, and particularly preferably less than 10 pg. It is most preferable that no impurity element is eluted at all. The amount of each impurity element may be 0 pg or more per 1 mL of resin, and in reality, it may be greater than 0 pg or 1 pg or more. By keeping the amount of each impurity element eluted from the anion exchange resin within the above range, highly sensitive analysis can be performed when the anion exchange resin is used for the analysis of impurity elements in a metal sample.

[0053] [3. Pretreatment method for anion exchange resin] A pretreatment method for an anion exchange resin according to one embodiment of the present invention (hereinafter also referred to as the present pretreatment method) includes step A: Step A: A step in which an anion exchange resin is brought into contact with a solution A containing two or more types of mineral acids two or more times. Step A is as described in [1. Method for analyzing impurity elements in metal samples].

[0054] This pretreatment method reduces the amount of each impurity element eluted from the anion exchange resin, allowing for highly sensitive analysis when the anion exchange resin is used for the analysis of impurity elements in a metal sample.

[0055] This pretreatment method may further include, in addition to step A, treatments that are commonly performed on anion exchange resins.

[0056] [4. Method for producing anion exchange resin] A method for producing an anion exchange resin according to one embodiment of the present invention (hereinafter also referred to as the present production method) is a method for producing an anion exchange resin in which the amount of impurity elements has been reduced, and includes a step of pretreatment by the present pretreatment method. The anion exchange resin produced is as described in [2. Anion Exchange Resin].

[0057] According to this manufacturing method, an anion exchange resin with reduced impurity element content can be produced. In this specification, "reduced impurity element content" means that the amount of each impurity element eluted from the anion exchange resin is preferably less than 200 pg per 1 mL of resin, preferably less than 100 pg, more preferably less than 50 pg, even more preferably less than 20 pg, particularly preferably less than 10 pg, and most preferably none at all.

[0058] [5. Column] A column according to one embodiment of the present invention (hereinafter also referred to as "this column") is a column for separating target elements and non-target elements using a metal sample dissolution, and is a column packed with the above-mentioned anion exchange resin.

[0059] The amount of anion exchange resin packed into this column is not particularly limited, but may be, for example, 1 mL or more, 2 mL or more, or 3 mL or more. In one embodiment, the amount of anion exchange resin packed into this column may be 10 mL or less.

[0060] Because this column is packed with the aforementioned anion exchange resin, when used to separate target elements from non-target elements, impurities originating from the anion exchange resin are less likely to contaminate the metal sample solution. Therefore, highly sensitive analysis of impurity elements in metal samples is possible.

[0061] The method for manufacturing this column includes steps A and D below: Step A: A step of contacting an anion exchange resin with a solution A containing two or more types of mineral acids two or more times; Step D: This step involves filling the column tube with the anion exchange resin that has undergone Step A. Step A is as described in [1. Method for Analyzing Impurity Elements in Metal Samples].

[0062] Step D is the step of filling the column tube with the anion exchange resin that has gone through step A. The method of filling the column tube with the anion exchange resin is not particularly limited and may be done by known methods.

[0063] In step D, the anion exchange resin may be suspended in solution A or pure water to form a slurry. In this case, the slurry may be poured from the top of the column tube and allowed to settle slowly so that the anion exchange resin layer is formed substantially uniformly. After settling is complete, bubbles and other contaminants in the anion exchange resin layer can be removed by passing pure water or solution A through the column.

[0064] Furthermore, the height and density of the anion exchange resin layer formed within the column can be adjusted as appropriate to ensure uniform flow path. The anion exchange resin layer can be adjusted, for example, by applying vibration by hand. By adjusting the anion exchange resin layer, the gaps between the anion exchange resin particles become nearly uniform, and the flow rate of the analyte can be stabilized.

[0065] The column after packing is not particularly limited, but for example, an equilibration treatment may be performed using pure water, one or more mineral acids, or solution A. Equilibration treatment stabilizes the anion exchange resin and flow path inside the column, enabling accurate analysis even when the target element is at a low concentration.

[0066] [6. Pre-processing system] A pretreatment system for an anion exchange resin according to one embodiment of the present invention includes a contact section for bringing the anion exchange resin into contact with a solution A containing two or more types of mineral acids two or more times. The solution A is as described in [1. Method for analyzing impurity elements in a metal sample]. Because the pretreatment system includes a contact section, it is possible to realize an anion exchange resin with a reduced amount of impurity elements.

[0067] An example of the aforementioned pretreatment system is shown in Figure 1. As shown in Figure 1, the pretreatment system may include a liquid supply switching unit, a contact unit (e.g., an immersion unit, a liquid passage unit), and a waste liquid recovery unit. The following describes pretreatment using the system shown in Figure 1.

[0068] In the pretreatment system shown in Figure 1, first, the liquid delivery switching unit can determine whether to use solution A1 or solution A2 to contact the anion exchange resin. Next, the anion exchange resin can be pretreated by bringing it into contact with solution A1 or A2 in the contact unit. Specifically, as shown in Figure 1, the solution A1 or A2 stored in the contact unit is brought into contact with the separation column. The contact unit may include an immersion unit for immersing the anion exchange resin in the stored solution A1, or a liquid passage unit for passing the stored solution A2 through the anion exchange resin. After contact between the anion exchange resin and solution A1 or A2 is complete, the column may be further contacted with an equilibration solution for column equilibration treatment. Contact with the equilibration solution allows for storage while maintaining the quality of the anion exchange resin and enables efficient replacement of the resin. The pretreated separation column can be detached and used for the analysis of impurity elements contained in metal samples, as described later. In other words, it can also be considered a column manufacturing system.

[0069] The pretreatment system may include two or more separation columns, as shown in Figure 1. Solution A1 or A2 that has come into contact with the anion exchange resin is recovered as waste liquid A1 or waste liquid A2 in the waste liquid recovery section, respectively.

[0070] One embodiment of the present invention may be an analysis system for impurity elements in a metal sample, equipped with the pretreatment system. The analysis system may include the pretreatment system described above, an analysis solution acquisition unit that obtains an analysis solution from a metal sample solution using an anion exchange resin that has undergone pretreatment by the pretreatment system, and an analysis unit that performs analysis of impurity elements in the metal sample using the analysis solution. Examples of devices included in the analysis unit include elemental analyzers that can be used for inductively coupled plasma mass spectrometry (the mass spectrometry unit may be, for example, a quadrupole type, a multi-quadrupole type, a double-focusing type, a time-of-flight type, etc.), inductively coupled plasma atomic emission spectrometry, graphite furnace atomic absorption spectrometry, total reflection X-ray fluorescence spectrometry, secondary ion mass spectrometry, and the like.

[0071] An example of the aforementioned analysis system is shown in Figure 2. As shown in Figure 2, the analysis system may include a dissolution preparation unit, a pretreatment unit, an analysis solution acquisition unit, and an analysis unit. Note that the analysis system shown in Figure 2 includes the pretreatment unit described above in the pretreatment unit. The analysis of impurity elements in a metal sample using the analysis system in Figure 2 will be described below.

[0072] In the analysis system shown in Figure 2, first, in the dissolution preparation unit, the metal sample solution obtained by dissolving the metal sample is prepared to a pH that separates the target element from non-target elements. In the pretreatment unit, the prepared solution is passed through a separation column to obtain an analytical solution. The obtained analytical solution is collected in a recovery container, and the target element is quantified using an inductively coupled plasma mass spectrometer, thereby allowing analysis of impurity elements contained in the metal sample.

[0073] Another example of the aforementioned analysis system is shown in Figure 3. Figure 3 is an example of a fully automated analysis system. As shown in Figure 3, the pre-processing system described above is provided in the pre-processing section. Furthermore, the analysis system shown in Figure 3 can perform fully automated analysis of impurity elements. The analysis of impurity elements in metal samples using the analysis system in Figure 3 will be described below.

[0074] In the analysis system shown in Figure 3, first, the metal sample is dissolved using an etching device in the metal sample dissolution section, and then the solution is prepared in the solution preparation section to separate the target element from the non-target element. If an alkaline solution is used as the decomposition solution, or if it is necessary to change the solution properties, the solvent may be removed using, for example, a heating and evaporation dryness device, and then the solution may be redissolved in another solvent (with separable properties) using a redissolution device to obtain the solution. Next, the obtained solution is passed through a separation column that has been pre-equilibrated with an equilibration solution to obtain the analyte. After collecting the obtained analyte in a recovery container, if it is necessary to analyze the target element with high sensitivity, or if the properties of the analyte negatively affect the analysis, the solvent may be removed in the analyte preparation section and the solution may be redissolved in another solvent using a redissolution device or the like to prepare the analyte. Solvent removal may be performed, for example, by a heating and evaporation dryness device. Redissolution into another solvent may also be performed using a redissolution device or the like. The target element may be quantified using an inductively coupled plasma mass spectrometer with the obtained analyte. This allows for highly sensitive and accurate analysis of impurity elements contained in metal samples.

[0075] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0076] One embodiment of the present invention may include the following configuration: <1> Method for analyzing impurity elements in a metal sample, including the following steps A to C: Step A: A step of contacting an anion exchange resin with a solution A containing two or more types of mineral acids two or more times; Step B: A step of obtaining an analytical solution from the metal sample solution using the anion exchange resin that has gone through Step A; Step C: A step in which impurity elements in a metal sample are analyzed using an analytical solution. <2> Solution A contains three or more types of mineral acids. <1> The analysis method described below. <3> A pretreatment method for anion exchange resin, including step A below: Step A: A step of contacting the anion exchange resin with a solution A containing two or more types of mineral acids two or more times. <4> A method for producing an anion exchange resin in which the amount of impurity elements is reduced, <3> A method for producing an anion exchange resin, comprising the step of pre-treating by the pre-treatment method described above. <5> An anion exchange resin for analyzing impurity elements in a metal sample, wherein the amount of each impurity element eluted from the anion exchange resin is measured by inductively coupled plasma mass spectrometry and is less than 200 pg per 1 mL of the anion exchange resin. <6> A column for separating target elements from non-target elements in a metal sample solution, <5> A column packed with the anion exchange resin described above. <7> A method for manufacturing a column for separating target elements and non-target elements from a metal sample solution, comprising the following steps A and D: Step A: A step of contacting an anion exchange resin with a solution A containing two or more types of mineral acids two or more times; Process D: A process in which the anion exchange resin that has gone through process A is packed into a column tube. <8> An anion exchange resin pretreatment system comprising a contact section for bringing an anion exchange resin into contact with a solution A containing two or more types of mineral acids two or more times. <9> <8> The pre-processing system described above, An analytical system for analyzing impurity elements in a metal sample, comprising: an analytical solution acquisition unit that obtains an analytical solution using an anion exchange resin that has undergone pretreatment by the aforementioned pretreatment system; and an analytical unit that performs analysis of impurity elements in the metal sample using the analytical solution. [Examples]

[0077] The present invention will be described in detail below based on examples and comparative examples, but the present invention is not limited thereto.

[0078] [Anion exchange resin] As the anion exchange resin, we used purified resin Muromac (Dowex 1×8 100~200 mesh), a strongly basic anion exchange resin. The properties of the anion exchange resin used are as follows. Resin base: Styrene-based, gel type Total exchange volume: 1.2 eq / L, wet Particle size: 0.25~0.11mm Moisture content: 39~45% Apparent density: 705g / L Commercially available ionic form: Cl - Durable temperature (Cl type): 100℃ Effective pH range: 0-14

[0079] [Quantitative determination of impurity elements in anion exchange resins] [Example 1] Step A1: 50 g of anion exchange resin and 200 g of ultrapure water were mixed in a Teflon sealed container, and the supernatant was discarded. Next, the anion exchange resin was immersed in 200 g of a mixed acid of 4 M hydrofluoric acid, 0.5 M nitric acid, and 0.8 M hydrochloric acid in a Teflon sealed container for more than 72 hours.

[0080] Step A2: 5 mL of the anion exchange resin immersed in Step A1 was packed into a cylindrical column container, and a mixed acid of 4 M hydrofluoric acid, 0.5 M nitric acid, and 0.8 M hydrochloric acid was passed through the anion exchange resin at a rate of 15 BV. Furthermore, an ion exchange column was prepared by passing a mixed acid of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid through the anion exchange resin at a rate of 15 BV.

[0081] Determination of impurity elements: 20 mL of a mixed acid solution consisting of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid was passed through the ion exchange column obtained in step A2. The mixture discharged from the column outlet was collected in an evaporation vessel. The collected mixture was then heated on a hot plate and evaporated to dryness. Furthermore, the residue in the evaporation vessel was collected with a solution containing 0.3 M nitric acid, and the amount of each element was quantified by inductively coupled plasma mass spectrometry. The amount of each element was less than 1 pg to less than 4 pg per 1 mL of resin.

[0082] Furthermore, the passage of the mixed acid for the quantification of impurity elements is merely a process for evaluating the effect of the pretreatment method according to one embodiment of the present invention (whether or not the impurity elements remaining in the ion exchange column have been reduced). In other words, the passage of the mixed acid for the quantification of impurity elements is not intended to be included as a step when actually implementing the pretreatment method or analytical method according to one embodiment of the present invention.

[0083] [Example 2] Step A1: 50 g of anion exchange resin and 200 g of ultrapure water were mixed in a Teflon sealed container, and the supernatant was discarded. Next, the anion exchange resin was immersed in 200 g of a mixed acid of 4 M hydrofluoric acid, 0.5 M nitric acid, and 0.8 M hydrochloric acid in a Teflon sealed container for more than 72 hours.

[0084] Step A2: 3 mL of the anion exchange resin immersed in Step A1 was packed into a cylindrical column container, and an ion exchange column was prepared by passing a mixed acid of 4 M hydrofluoric acid, 0.5 M nitric acid, and 0.8 M hydrochloric acid through the anion exchange resin at a rate of 33 BV.

[0085] Determination of impurity elements: 20 mL of a mixed acid solution consisting of 4 M hydrofluoric acid, 0.5 M nitric acid, and 0.8 M hydrochloric acid was passed through the ion exchange column obtained in step A2. The mixture discharged from the column outlet was collected in an evaporation vessel. The collected mixture was then heated on a hot plate and evaporated to dryness. Furthermore, the residue in the evaporation vessel was collected with a solution containing 0.3 M nitric acid, and the amount of each element was quantified by inductively coupled plasma mass spectrometry. The amount of each element was less than 1 pg to less than 4 pg per 1 mL of resin.

[0086] [Example 3] Step A1: 24 g of anion exchange resin and 80 g of ultrapure water were mixed in a Teflon sealed container, and the supernatant was discarded. Next, the anion exchange resin was immersed in 80 g of a mixed acid of 2 M hydrofluoric acid, 0.3 M nitric acid, and 0.4 M hydrochloric acid in a Teflon sealed container for 28 days.

[0087] Step A2: 3 mL of the anion exchange resin immersed in Step A1 was packed into a cylindrical column container, and an ion exchange column was prepared by passing a mixed acid of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid through the anion exchange resin at a rate of 40 BV.

[0088] Determination of impurity elements: 20 mL of a mixed acid solution consisting of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid was passed through the ion exchange column obtained in step A2. The mixture discharged from the column outlet was collected in an evaporation vessel. The collected mixture was then heated on a hot plate and evaporated to dryness. Furthermore, the residue in the evaporation vessel was collected with a solution containing 0.3 M nitric acid, and the amount of each element was quantified by inductively coupled plasma mass spectrometry. The amount of each element was less than 1 pg to less than 7 pg per 1 mL of resin.

[0089] [Example 4] Step A1: 50 g of anion exchange resin and 200 g of ultrapure water were mixed in a Teflon sealed container, and the supernatant was discarded. Next, the anion exchange resin was immersed in 200 g of a mixed acid of 4 M hydrofluoric acid, 0.5 M nitric acid, and 0.8 M hydrochloric acid in a Teflon sealed container for more than 72 hours.

[0090] Step A2: 3 mL of the anion exchange resin immersed in Step A1 was packed into a cylindrical column container, and an ion exchange column was prepared by passing a mixed acid of 2 M hydrofluoric acid, 0.3 M nitric acid, and 0.4 M hydrochloric acid through the anion exchange resin at a rate of 17 BV.

[0091] Determination of impurity elements: 20 mL of a mixed acid solution consisting of 2 M hydrofluoric acid, 0.3 M nitric acid, and 0.4 M hydrochloric acid was passed through the ion exchange column obtained in step A2. The mixture discharged from the column outlet was collected in an evaporation vessel. The collected mixture was then heated on a hot plate and evaporated to dryness. Furthermore, the residue in the evaporation vessel was collected with a solution containing 0.3 M nitric acid, and the amount of each element was quantified by inductively coupled plasma mass spectrometry. The amount of each element was less than 1 pg to less than 5 pg per 1 mL of resin.

[0092] [Example 5] Step A1: 12 g of anion exchange resin and 40 g of ultrapure water were mixed in a Teflon sealed container, and the supernatant was discarded. Next, the anion exchange resin was immersed in 40 g of a mixed acid of 0.5 M nitric acid and 0.8 M hydrochloric acid in the Teflon sealed container for 72 hours.

[0093] Step A2: 3 mL of the anion exchange resin immersed in Step A1 was packed into a cylindrical column container, and a mixed acid of 4 M hydrofluoric acid, 0.5 M nitric acid, and 0.8 M hydrochloric acid was passed through the anion exchange resin at a rate of 33 BV. Furthermore, a mixed acid of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid was passed through the anion exchange resin at a rate of 67 BV to prepare an ion exchange column.

[0094] Determination of impurity elements: 20 mL of a mixed acid solution consisting of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid was passed through the ion exchange column obtained in step A2. The mixture discharged from the column outlet was collected in an evaporation vessel. The collected mixture was then heated on a hot plate and evaporated to dryness. Furthermore, the residue in the evaporation vessel was collected with a solution containing 0.3 M nitric acid, and the amount of each element was quantified by inductively coupled plasma mass spectrometry. The quantification results showed that 51 pg of Cr was detected, and the amounts of all other elements were less than 1 pg to less than 6 pg per 1 mL of resin.

[0095] [Example 6] Step A1: 12 g of anion exchange resin and 40 g of ultrapure water were mixed in a Teflon sealed container, and the supernatant was discarded. Next, the anion exchange resin was immersed in 40 g of a mixed acid of 4 M hydrofluoric acid and 0.8 M hydrochloric acid in a Teflon sealed container for 72 hours.

[0096] Step A2: 3 mL of the anion exchange resin immersed in Step A1 was packed into a cylindrical column container, and a mixed acid of 4 M hydrofluoric acid, 0.5 M nitric acid, and 0.8 M hydrochloric acid was passed through the anion exchange resin at a rate of 33 BV. Furthermore, an ion exchange column was prepared by passing a mixed acid of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid through the anion exchange resin at a rate of 67 BV.

[0097] Determination of impurity elements: 20 mL of a mixed acid of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid was passed through the ion exchange column obtained in step A2. The mixture discharged from the column outlet was collected in an evaporation vessel. The collected mixture was then heated on a hot plate and evaporated to dryness. Furthermore, the residue in the evaporation vessel was collected with a solution containing 0.3 M nitric acid, and the amount of each element was quantified by inductively coupled plasma mass spectrometry. The quantification results showed that 37 pg of Cr was detected, and the amounts of all other elements were less than 1 pg to less than 6 pg per 1 mL of resin.

[0098] [Example 7] Step A1: 12 g of anion exchange resin and 40 g of ultrapure water were mixed in a Teflon sealed container, and the supernatant was discarded. Next, the anion exchange resin was immersed in 40 g of a mixed acid of 4 M hydrofluoric acid and 0.5 M nitric acid in a Teflon sealed container for 72 hours.

[0099] Step A2: 3 mL of the anion exchange resin immersed in Step A1 was packed into a cylindrical column container, and a mixed acid of 4 M hydrofluoric acid, 0.5 M nitric acid, and 0.8 M hydrochloric acid was passed through the anion exchange resin at a rate of 33 BV. Furthermore, an ion exchange column was prepared by passing a mixed acid of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid through the anion exchange resin at a rate of 67 BV.

[0100] Determination of impurity elements: 20 mL of a mixed acid solution consisting of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid was passed through the ion exchange column obtained in step A2. The mixture discharged from the column outlet was collected in an evaporation vessel. The collected mixture was then heated on a hot plate and evaporated to dryness. Furthermore, the residue in the evaporation vessel was collected with a solution containing 0.3 M nitric acid, and the amount of each element was quantified by inductively coupled plasma mass spectrometry. The quantification results showed that 30 pg of Cr was detected, and the amounts of all other elements were less than 1 pg to less than 6 pg per 1 mL of resin.

[0101] [Example 8] Step A1: 24 g of anion exchange resin and 80 g of ultrapure water were mixed in a Teflon sealed container, and the supernatant was discarded. Next, the anion exchange resin was immersed in 80 g of a mixed acid of 4 M hydrofluoric acid and 0.8 M hydrochloric acid in a Teflon sealed container for 168 hours.

[0102] Step A2: 3 mL of the anion exchange resin immersed in Step A1 was packed into a cylindrical column container, and a mixed acid of 4 M hydrofluoric acid and 0.8 M hydrochloric acid was passed through the anion exchange resin at a rate of 33 BV. Furthermore, for the purpose of column equilibration, a mixed acid of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid was passed through the anion exchange resin at a rate of 7 BV to prepare the ion exchange column. In Example 8 and Example 9 described later, a mixed acid of two mineral acids is used in Step A2, but a mixed acid of three mineral acids is used in the determination of impurity elements following Step A2. Therefore, in order to match the acidity of the solution when determining impurity elements, a mixed acid of three mineral acids was passed through the column immediately after Step A2 as a column equilibration treatment.

[0103] Determination of impurity elements: 20 mL of a mixed acid solution consisting of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid was passed through the ion exchange column obtained in step A2. The mixture discharged from the column outlet was collected in an evaporation vessel. The collected mixture was then heated on a hot plate and evaporated to dryness. Furthermore, the residue in the evaporation vessel was collected with a solution containing 0.3 M nitric acid, and the amounts of each element were quantified by inductively coupled plasma mass spectrometry. The quantification results showed that 180 pg of Cr and 180 pg of Zn were detected, and the amounts of other elements were all between less than 1 pg and less than 6 pg per 1 mL of resin.

[0104] [Example 9] Step A1: 24 g of anion exchange resin and 80 g of ultrapure water were mixed in a Teflon sealed container, and the supernatant was discarded. Next, the anion exchange resin was immersed in 80 g of a mixed acid of 4 M hydrofluoric acid and 0.5 M nitric acid in a Teflon sealed container for 168 hours.

[0105] Step A2: 3 mL of the anion exchange resin immersed in Step A1 was packed into a cylindrical column container, and a mixed acid of 4 M hydrofluoric acid and 0.5 M nitric acid was passed through the anion exchange resin at a rate of 33 BV. Furthermore, for the purpose of column equilibration, a mixed acid of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid was passed through the anion exchange resin at a rate of 7 BV to prepare an ion exchange column.

[0106] Determination of impurity elements: 20 mL of a mixed acid of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid was passed through the ion exchange column obtained in step A2. The solution discharged from the column outlet was collected in an evaporation vessel. The resulting mixture was then heated on a hot plate and evaporated to dryness. Furthermore, the residue in the evaporation vessel was collected with a solution containing 0.3 M nitric acid, and the amount of each element was quantified by inductively coupled plasma mass spectrometry. The quantification results showed that 33 pg of Cr was detected, 10 pg of Zn was detected, and the amounts of other elements were all between less than 1 pg and less than 6 pg per 1 mL of resin.

[0107] [Comparative Example 1] Step A1: 24 g of anion exchange resin and 80 g of ultrapure water were mixed in a sealed Teflon container, and the supernatant was discarded. Next, the anion exchange resin was immersed in 80 g of 3M hydrochloric acid in a sealed Teflon container for more than 72 hours.

[0108] Step A2: 3 mL of the anion exchange resin immersed in Step A1 was packed into a cylindrical column container, and 20 BV of 3 M hydrochloric acid was passed through the anion exchange resin. Furthermore, to equilibrate the column, a mixed acid of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid was passed through the anion exchange resin at a rate of 7 BV to prepare the ion exchange column.

[0109] Determination of impurity elements: 20 mL of a mixed acid containing 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid was passed through the ion exchange column obtained in step A2. The mixture discharged from the column outlet was collected in an evaporation vessel. The collected mixture was then heated on a hot plate and evaporated to dryness. Furthermore, the residue in the evaporation vessel was collected with a solution containing 0.3 M nitric acid, and the amount of each element was quantified by inductively coupled plasma mass spectrometry to determine the amount of impurity elements eluted per 1 mL of anion exchange resin. As mentioned above, the passage of the mixed acid for the determination of impurity elements is not a washing step, so the pretreatment in Comparative Examples 1 to 3 does not involve contacting the anion exchange resin with a solution containing two or more mineral acids two or more times.

[0110] [Comparative Example 2] Step A1: 70g of anion exchange resin and 150g of ultrapure water were mixed in a Teflon sealed container, and the supernatant was discarded.

[0111] Step A2: 3 mL of the anion exchange resin obtained in Step A1 was packed into a cylindrical column container, and an ion exchange column was prepared by passing a mixed acid of 4 M hydrofluoric acid, 0.5 M nitric acid, and 0.8 M hydrochloric acid through the anion exchange resin at a rate of 67 BV.

[0112] Determination of impurity elements: 10 mL of a mixed acid of 4 M hydrofluoric acid, 0.5 M nitric acid, and 0.8 M hydrochloric acid was passed through the ion exchange column obtained in step A2. The solution discharged from the column outlet was collected in an evaporation vessel. Then, it was heated on a hot plate and evaporated to dryness. Furthermore, the residue in the evaporation vessel was collected with a solution containing 0.3 M nitric acid, and the amount of each element was quantified by inductively coupled plasma mass spectrometry to determine the amount of impurity elements eluted per 1 mL of anion exchange resin.

[0113] [Comparative Example 3] Step A1: 24 g of anion exchange resin and 80 g of ultrapure water were mixed in a sealed Teflon container, and the supernatant was discarded. Next, the anion exchange resin was immersed in 4M hydrofluoric acid in a sealed Teflon container for 72 hours.

[0114] Step A2: 3 mL of the anion exchange resin immersed in Step A1 was packed into a cylindrical column container, and 33 BV of 4 M hydrofluoric acid was passed through the anion exchange resin. Furthermore, to equilibrate the column, a mixed acid of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid was passed through the anion exchange resin at a rate of 7 BV to prepare the ion exchange column.

[0115] Determination of impurity elements: 20 mL of a mixed acid of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid was passed through the ion exchange column obtained in step A2. The solution discharged from the column outlet was collected in an evaporation vessel. The resulting mixture was then heated on a hot plate and evaporated to dryness. Furthermore, the residue in the evaporation vessel was collected with a solution containing 0.3 M nitric acid, and the amount of each element was quantified by inductively coupled plasma mass spectrometry to determine the amount of impurity elements eluted per 1 mL of anion exchange resin.

[0116] 〔result〕 Table 1 shows the solutions A1 and A2 used for washing in steps A1 and A2 of each example and comparative example. Table 2 shows the measurement results by inductively coupled plasma mass spectrometry, expressed as the amount of impurity elements eluted per 1 mL of resin (pg / resin mL).

[0117] [Table 1]

[0118] [Table 2]

[0119] Tables 1 and 2 show that the anion exchange resins of Examples 1-7 and 9, which used two or more types of mineral acids in steps A1 and A2, all had an elution amount of impurity elements of less than 60 pg per 1 mL of resin. Similarly, the anion exchange resin of Example 8 also had an elution amount of impurity elements of less than 6 pg, except for Zn and Cr. On the other hand, Comparative Examples 1 and 3, which did not use two or more types of mineral acids in steps A1 and / or A2, had a high elution amount of impurity elements. Similarly, Comparative Example 2, which had only one contact with solution A, also showed a high elution amount of impurity elements.

[0120] [Quantitative determination of impurity elements in thin films] [Example 10] The impurity elements in an HfO2 thin film on the surface of a silicon wafer were quantified. A 3 nm thick HfO2 film deposited on a 200 mm diameter silicon wafer was recovered by direct acid droplet decomposition (DADD) using 20 M HF. Subsequently, dissolution solutions were prepared using hydrofluoric acid (1 M), nitric acid (0.1 M), and hydrochloric acid (0.2 M) with ultrapure water.

[0121] In Example 1, 3 mL of the anion exchange resin was packed into a column, and the above-described solution was passed through it at a rate of 1 mL / min. The solution 10-1 discharged from the column outlet was collected in an evaporation vessel. Next, a mixed acid of 1 M hydrofluoric acid, 0.1 M nitric acid, and 0.2 M hydrochloric acid was passed through the column, and the solution 10-2 discharged from the column was collected and mixed with solution 10-1 to obtain a mixture. The resulting mixture was then heated on a hot plate and evaporated to dryness. Finally, the residue in the evaporation vessel was collected with a solution containing 0.3 M nitric acid, and the amounts of each element were quantified by inductively coupled plasma mass spectrometry.

[0122] Furthermore, to confirm the accuracy of the quantification, the recovery rate was calculated by analyzing standard additive solutions prepared by adding 0.2 ng or 1 ng of each element to the obtained dissolution using the same procedure. For comparison, the results obtained using a column packed with 3 mL of the anion exchange resin obtained in Comparative Example 1 were also calculated (Comparative Example 4). The quantification results, calculation results, and recovery rates for each element are shown in Table 3.

[0123] [Table 3]

[0124] Table 3 shows that the amount of impurity elements in Example 10 is lower than that in Comparative Example 4. Furthermore, the recovery rate for all elements was 80-120%. Therefore, this analytical method demonstrates that it can accurately quantify impurity elements in HfO2 films deposited on silicon wafers.

[0125] [Quantitative determination of impurity elements in thin films] [Example 11] The impurity elements in a ZnO thin film on the surface of a silicon wafer were quantified. A 10 nm thick ZnO film deposited on a 300 mm diameter silicon wafer was cut into 5 cm squares to prepare a sample. Direct acid droplet decomposition (DADD) was performed using 20 M HF, and the samples were collected in a Teflon evaporator. The resulting solution was then heated on a hot plate and evaporated to dryness. Furthermore, the residue in the evaporator was redissolved with a solution containing 9 M hydrochloric acid.

[0126] An ion exchange column was prepared by passing 5 mL of the anion exchange resin obtained in Example 1 through a column packed with 9 M hydrochloric acid at a rate of 5 BV to equilibrate the column. A redissolving solution was added to the ion exchange column, and 9 M hydrochloric acid was passed through it at a rate of 0.3 mL / min. Solution 11-1 discharged from the column outlet was collected in an evaporation vessel. Next, 3 M hydrochloric acid was passed through it at a rate of 0.5 mL / min, and solution 11-2 discharged from the column was collected and mixed with solution 11-1 to obtain a mixture. The resulting mixture was then heated on a hot plate and evaporated to dryness. The residue in the evaporation vessel was then collected with a solution containing 0.3 M nitric acid, and the amounts of each element were quantified by inductively coupled plasma mass spectrometry.

[0127] Furthermore, to confirm the accuracy of the quantification, samples cut into 5cm squares from the same 300mm silicon wafer sample were prepared, dissolved using a droplet method with 20M HF, and collected in a Teflon evaporator. The standard additive solution, to which 20ng of each element was added to the obtained solution, was analyzed using the same procedure to calculate the additive recovery rate. In addition, for comparison, the results obtained using a column packed with 5mL of anion exchange resin obtained in Comparative Example 1 were calculated (Comparative Example 5). The quantitative results, calculation results, and additive recovery rates for each element are shown in Table 4.

[0128] [Table 4] [Industrial applicability]

[0129] The present invention can be suitably used as a method for analyzing impurity elements in a metal sample.

Claims

1. Method for analyzing impurity elements in a metal sample, including the following steps A to C: Step A: A step of contacting an anion exchange resin with a solution A containing two or more types of mineral acids two or more times; Step B: A step of obtaining an analytical solution from the metal sample solution using the anion exchange resin that has gone through Step A; Step C: A step in which impurity elements in a metal sample are analyzed using an analytical solution.

2. The analytical method according to claim 1, wherein solution A contains three or more types of mineral acids.

3. A pretreatment method for anion exchange resin, including step A below: Step A: A step of contacting an anion exchange resin with a solution A containing two or more types of mineral acids two or more times.

4. A method for producing an anion exchange resin in which the amount of impurity elements is reduced, comprising the step of pre-treating by the pre-treatment method described in claim 3.

5. A method for manufacturing a column for separating target elements and non-target elements from a metal sample solution, comprising the following steps A and D: Step A: A step of contacting an anion exchange resin with a solution A containing two or more types of mineral acids two or more times; Process D: A process in which the anion exchange resin that has gone through process A is packed into a column tube.

6. An anion exchange resin pretreatment system comprising a contact section for bringing an anion exchange resin into contact with a solution A containing two or more types of mineral acids two or more times.

7. The pre-processing system according to claim 6, An analytical solution acquisition unit that obtains an analytical solution using an anion exchange resin that has undergone pretreatment by the aforementioned pretreatment system, An analytical system for analyzing impurity elements in a metal sample, comprising: an analytical unit that performs analysis of impurity elements in a metal sample using the aforementioned analytical solution.

Images