Concentration measuring method and device

Abstract

To enable the concentration of each dissolved component to be measured, even when the state of a used component is unknown.SOLUTION: A first processing unit 102 identifies a use solution from the optical spectrum of the use solution measured by a spectroscopic measurer 101. The first processing unit 102 identifies a solution, as a use solution, of which the value substituted by the measured optical spectrum corresponds to a regression equation exceeding a set threshold. A second processing unit 103 finds, from the optical spectrum measured by the spectroscopic measurer 101, the concentration of each kind of known component of the solution identified by the first processing unit 102 on the basis of calibration information created on the basis of a reference solution that serves as a reference for the identified use solution.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and an apparatus for measuring the concentration of a solution in which multiple components are dissolved. [Background technology]

[0002] In the manufacturing process of semiconductor devices and liquid crystal display devices, solutions in which multiple acids are dissolved are used. For example, in the cleaning of silicon substrates and the etching process of lithography technology, processing solutions in which multiple acids such as hydrofluoric acid, nitric acid, acetic acid, phosphoric acid, hydrochloric acid, and sulfuric acid are dissolved are used. When using this type of processing solution, concentration management is important from the viewpoints of improving product yield, safety, work efficiency, etc.

[0003] In this concentration management, the concentration of each of the multiple acids dissolved in the solution being used is measured. For example, there is a technique for determining the concentration of multiple acids dissolved in a solution by utilizing the light absorption of each acid (see Patent Document 1). In this technique, a calibration curve formula showing the relationship between the concentration in the solution and the light absorption is prepared for each of the multiple acids, and an appropriate calibration curve formula is used depending on the solution to be measured. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 06-265471 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned technique is based on the premise that the type of component, such as an acid, used (dissolved) in the solution to be measured is known. The above-mentioned technique has a problem in that if the type of component dissolved in the solution to be measured is unknown, the concentration cannot be measured. When the solution to be measured is changed, even if the type of component used in the changed solution is known, the measurement conditions must be changed, which is a problem in that the measurement is time-consuming.

[0006] The present invention has been made to solve the above problems, and has an object to make it possible to measure the concentration of each dissolved component even if the state of the component used is unknown. [Means for solving the problem]

[0007] The concentration measuring device of the present invention comprises a spectrometer that measures the spectroscopic spectrum of a used solution to be measured, a first processing unit configured to identify the used solution from the spectroscopic spectrum of the used solution measured by the spectrometer, and a second processing unit configured to determine the concentration of each type of known component of the solution identified by the first processing unit from the spectroscopic spectrum measured by the spectrometer based on calibration information created on the basis of a reference solution that serves as a reference for the identified used solution, and the used solution is any of a number of solutions in which the types of dissolved components are known.

[0008] In one configuration example of the above-mentioned concentration measuring device, a memory unit is provided that is configured to store regression equations of the spectroscopic spectra of a plurality of solutions in which the types of dissolved components are known, and a first processing unit identifies, as a use solution, a solution corresponding to a regression equation in which a value substituted with the measured spectroscopic spectrum exceeds a set threshold value.

[0009] In one configuration example of the concentration measuring device, the calibration information is composed of a concentration regression equation relating to the concentrations of known components in each of a plurality of solutions in which the types of dissolved components are known.

[0010] In one configuration example of the concentration measuring device, a flow path is provided for transporting the used solution to a treatment device that uses the used solution, and the spectrometer measures the optical spectrum of the used solution flowing through the flow path.

[0011] Furthermore, the concentration measurement method of the present invention includes a first step of selecting one of a plurality of solutions containing known types of dissolved components as a use solution, a second step of measuring the spectroscopic spectrum of the use solution, a third step of identifying the use solution from the measured spectroscopic spectrum, and a fourth step of determining the concentration of each type of known component in the identified solution from the measured spectroscopic spectrum, based on calibration information created on the basis of a reference solution that serves as a reference for the identified use solution.

[0012] In one configuration example of the above-mentioned concentration measurement method, a regression equation of the optical spectrum of each of a plurality of solutions in which the types of dissolved components are known is prepared, and in the third step, a solution corresponding to the regression equation in which the value substituted with the measured optical spectrum exceeds a set threshold value is identified as the solution to be used.

[0013] In one configuration example of the concentration measurement method, the calibration information is composed of a concentration regression equation relating to the concentrations of known components in each of a plurality of solutions in which the types of dissolved components are known. Effect of the Invention

[0014] As described above, according to the present invention, the spectroscopic spectrum of a use solution selected from a plurality of solutions in which the types of dissolved components are known is measured, and the use solution is identified from the measured spectroscopic spectrum. Therefore, even if it is unknown which use solution was selected and the state of the components used is unknown, the concentration of each dissolved component can be measured. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram showing the configuration of a concentration measuring device according to an embodiment of the present invention. [Diagram 2]FIG. 2 is a flowchart illustrating a concentration measuring method according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a diagram showing a hardware configuration of a concentration measuring device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] A concentration measuring device 100 according to an embodiment of the present invention will be described below with reference to Fig. 1. This concentration measuring device 100 includes a spectrometer 101, a first processing unit 102, a second processing unit 103, and a storage unit 104.

[0017] Spectrometer 101 measures the spectrum of a used solution to be measured. For example, it is provided with a flow path 113 that transports a used solution to a treatment device 112 that uses the used solution, and spectrometer 101 measures the spectrum of the used solution flowing through flow path 113. Flow path 113 is, for example, a pipe (tube) made of a fluororesin such as perfluoroalkoxyalkane. Spectrometer 101 is made up of a light source, a spectroscope, etc.

[0018] The solution used is stored in a supply device 111 and is supplied from the supply device 111. The solution used is any one of a plurality of solutions in which the types of components dissolved therein are known. The memory unit 104 stores a regression equation of the spectroscopic spectrum of each of a plurality of solutions in which the types of components dissolved therein are known. For example, the solution is a cleaning liquid, and the processing device 112 is a wafer cleaning device. Chemical solution A, chemical solution B, and chemical solution C are used as the cleaning liquid.

[0019] The chemical solutions A, B, and C each have different dissolved components. For example, the chemical solution A is an aqueous solution in which components a and b are dissolved. The chemical solution B is an aqueous solution in which components b and c are dissolved. Each of the chemical solutions C is an aqueous solution in which components a and c are dissolved. The memory unit 104 stores a regression equation A of the optical spectrum of the chemical solution A, a regression equation B of the optical spectrum of the chemical solution B, and a regression equation C of the optical spectrum of the chemical solution C. The types of chemical solutions are not limited to three, and can be four or more.

[0020] The first processing unit 102 identifies the used solution from the spectroscopic spectrum of the used solution measured by the spectrometer 101. The first processing unit 102 identifies, as the used solution, a solution corresponding to a regression equation in which a value substituted with the measured spectroscopic spectrum exceeds a set threshold value.

[0021] The second processing unit 103 obtains the concentration of each type of known component in the solution identified by the first processing unit 102 from the spectroscopic spectrum measured by the spectrometer 101, based on calibration information created based on a reference solution that serves as a reference for the identified use solution. The calibration information can be a concentration regression equation relating to the concentration of a known component in each of a plurality of solutions in which the types of dissolved components are known. For example, a regression equation for the concentration of each of components a, b, and c when these are in an aqueous solution is created, and the concentration of each component can be calculated by substituting the absorbance of the use solution into the concentration regression equation.

[0022] Next, a concentration measuring method according to an embodiment of the present invention will be described with reference to Fig. 2. First, in step S101, one of a plurality of solutions (chemical solution A, chemical solution B, chemical solution C) in which the types of multiple dissolved components are known is selected as a use solution. Any of the chemical solutions selected as the use solution is supplied from a supply device 111 to a processing device 112 via a flow path 113. For example, the types of multiple dissolved components in each of the plurality of solutions (chemical solution A, chemical solution B, chemical solution C) are known, but it is unknown which of these has been selected as the use solution.

[0023] Next, in a second step S102, for example, the spectroscopic spectrum of the solution being used transported through the flow path 113 is measured by the spectrometer 101.

[0024] Next, in a third step S103, the first processing unit 102 identifies the solution used from the measured spectrum. If the type of the liquid to be measured is liquid A, then each regression equation is created so that the measured spectrum, when substituted into regression equation A, will produce a large value, and when substituted into regression equations B and C, will produce values ​​close to zero. Similarly, liquids B and C are set so that they show large values ​​only when substituted into the corresponding regression equations, and show values ​​close to zero in the other regression equations (see Table 1). The "large value" when substituted into the regression equation corresponding to each liquid is not particularly limited in value, but can be set so as to be clearly distinguishable from values ​​close to zero. By these means, the type of the liquid used is automatically identified.

[0025] [Table 1]

[0026] Next, in a fourth step S104, the concentration of each type of known component in the solution identified by the first processing unit 102 is obtained from the measured spectrum based on calibration information created by the second processing unit 103 based on a reference solution that serves as a reference for the identified use solution. The calibration information is composed of concentration regression equations relating to the concentrations of known components in each of a plurality of solutions in which the types of components dissolved therein are known. For example, the calibration information is composed of regression equations for the concentrations of components a, b, and c when these are dissolved in aqueous solutions.

[0027] The first processing unit 102, the second processing unit 103, and the storage unit 104 of the concentration measuring device according to the embodiment described above may be a computer device including a CPU (Central Processing Unit) 301, a main storage device 302, an external storage device 303, a network connection device 304, etc., as shown in Fig. 3, and the above-mentioned functions (concentration measurement method) may be realized by the CPU 301 operating (executing the program) according to a program deployed in the main storage device 302. The above-mentioned program is a program for causing a computer to execute the concentration measurement method shown in the embodiment described above. The network connection device 304 is connected to a network 305. Also, each function may be distributed to a plurality of computer devices.

[0028] As described above, according to the present invention, the spectroscopic spectrum of a use solution selected from a plurality of solutions in which the types of dissolved components are known is measured, and the use solution is identified from the measured spectroscopic spectrum. Therefore, even if it is unknown which use solution has been selected and the state of the components used is unknown, it becomes possible to measure the concentration of each dissolved component.

[0029] It should be noted that the present invention is not limited to the above-described embodiments, and it is apparent that many modifications and combinations can be made by a person having ordinary knowledge in the art within the technical concept of the present invention. [Explanation of symbols]

[0030] 100: concentration measuring device, 101: spectrometer, 102: first processing unit, 103: second processing unit, 104: memory unit, 111: supplying device, 112: processing device, 113: flow path.

Claims

1. A first step of selecting one of a plurality of solutions containing a plurality of dissolved components of known types as a working solution; a second step of measuring the spectroscopic spectrum of the use solution; A third step of identifying the use solution from the measured spectroscopic spectrum; A fourth step of determining the concentration of each type of known component in the specified solution from the measured spectroscopic spectrum based on calibration information created based on a standard solution that serves as a standard for the specified use solution; Equipped with A regression equation for the spectroscopic spectrum of each of a plurality of solutions in which the types of dissolved components are known is prepared; The third step is to identify a solution corresponding to a regression equation in which a value obtained by substituting the measured spectroscopic spectrum exceeds a set threshold value as the use solution, and automatically determine the type of chemical of the use solution. A method for measuring concentration.

2. 2. The method for measuring concentration according to claim 1, The calibration information is a concentration regression equation relating to the concentrations of known components in each of a plurality of solutions in which the types of components dissolved therein are known. A method for measuring concentration.

3. a spectrophotometer for measuring the spectroscopic spectrum of the solution to be measured; a first processing unit configured to identify the use solution from the spectroscopic spectrum of the use solution measured by the spectrometer; a second processing unit configured to obtain the concentration of each type of known component in the solution identified by the first processing unit from the spectroscopic spectrum measured by the spectrometer based on calibration information created on a reference solution that serves as a reference for the identified use solution; and A memory unit configured to store a regression equation of each of the spectroscopic spectra of a plurality of solutions in which the types of a plurality of dissolved components are known; Equipped with the first processing unit identifies a solution corresponding to a regression equation in which a value obtained by substituting the measured spectroscopic spectrum exceeds a set threshold as the use solution, and automatically determines the type of chemical of the use solution; The use solution is one of a number of solutions containing a number of known dissolved components. A concentration measuring device comprising:

4. 4. The concentration measuring device according to claim 3, The calibration information is composed of a concentration regression equation relating to the concentrations of known components in each of a plurality of solutions in which the types of components dissolved therein are known. A concentration measuring device comprising:

5. 5. The concentration measuring device according to claim 3, a flow path for transporting the use solution to a treatment device that uses the use solution; The spectrometer measures the spectrum of the working solution flowing through the flow path. A concentration measuring device comprising:

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