JP7640317B2 - Concentration measuring method and device - Google Patents

Description

The present invention relates to a method and device for measuring the concentration of a solution containing multiple dissolved components.

Solutions containing multiple acids are used in the manufacturing processes of semiconductor devices and liquid crystal display devices. For example, in the cleaning of silicon substrates and the etching process of lithography technology, processing solutions containing multiple acids such as hydrofluoric acid, nitric acid, acetic acid, phosphoric acid, hydrochloric acid, and sulfuric acid are used. When using this type of processing solution, concentration management is important from the standpoint of improving product yields, safety, and work efficiency.

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 equation that shows 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 equation is used depending on the solution to be measured.

Japanese Patent Application Publication No. 06-265471

However, the above-mentioned technology is based on the premise that the type of component, such as acid, used (dissolved) in the solution to be measured is known. With the above-mentioned technology, 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, resulting in a problem of measurement being time-consuming.

The present invention was made to solve the above problems, and aims to make it possible to measure the concentration of each dissolved component even if the state of the components used is unknown.

The concentration measuring device according to 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 from a reference solution that serves as a reference for the identified used solution, and the used solution is any one of a number of solutions in which the types of dissolved components are known.

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

In one example configuration of the concentration measurement device described above, the calibration information is composed of a concentration regression equation for the concentration of a known component in each of a number of solutions in which the types of dissolved components are known.

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

The concentration measurement method according to the present invention includes a first step of selecting one of a number 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 from a reference solution that serves as a reference for the identified use solution.

In one configuration example of the above concentration measurement method, a regression equation for 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.

In one example of the above concentration measurement method, the calibration information is composed of a concentration regression equation for the concentration of a known component in each of a number of solutions in which the types of dissolved components are known.

As described above, according to the present invention, the spectroscopic spectrum of a use solution selected from among a number 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.

FIG. 1 is a diagram showing the configuration of a concentration measuring device according to an embodiment of the present invention. FIG. 2 is a flowchart illustrating a concentration measuring method according to an embodiment of the present invention. FIG. 3 is a diagram showing a hardware configuration of a concentration measuring apparatus according to an embodiment of the present invention.

Hereinafter, a concentration measuring device 100 according to an embodiment of the present invention will be described with reference to FIG. 1. The concentration measuring device 100 includes a spectrometer 101, a first processing unit 102, a second processing unit 103, and a memory unit 104.

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

The solution used is stored in the supply device 111 and is supplied from the supply device 111. The solution used is any one of a number of solutions in which the types of components dissolved therein are known. The memory unit 104 stores the regression equations of the spectroscopic spectra of each of a number 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 solutions used as cleaning liquids.

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

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

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 from 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 the known components 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 made into 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.

Next, a concentration measurement 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 dissolved components are known is selected as the solution to be used. One of the chemical solutions selected as the solution to be used is supplied from the supply device 111 to the processing device 112 via the flow path 113. For example, the types of 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 solution to be used.

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

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 when the measured spectrum is substituted into regression equation A, a large value is obtained, and when substituted into regression equations B and C, the values are near zero. Similarly, for liquid B and C, the values are set so that they show large values only when substituted into the corresponding regression equation, and show values near 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, but can be set so that it is clearly distinguishable from values near zero. In this way, the type of liquid used is automatically identified.

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 spectroscopic 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 dissolved components are known. For example, for each of components a, b, and c, the calibration information is composed from the regression equations of the concentrations when these are made into aqueous solutions.

The first processing unit 102, the second processing unit 103, and the storage unit 104 of the concentration measuring device according to the above-mentioned embodiment 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 above-mentioned embodiment. The network connection device 304 is connected to a network 305. Also, each function may be distributed among multiple computer devices.

As described above, according to the present invention, the spectroscopic spectrum of a use solution selected from among a number 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, it is possible to measure the concentration of each dissolved component.

The present invention is not limited to the embodiments described above, and it is clear that many modifications and combinations can be implemented by those with ordinary skill in the art within the technical concept of the present invention.

100...concentration measuring device, 101...spectrometer, 102...first processing unit, 103...second processing unit, 104...storage unit, 111...supply device, 112...processing device, 113...flow path.

Claims (5)

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;
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 a reference solution that serves as a reference for the identified use solution ,
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. The method for measuring concentration according to claim 1 ,
The concentration measuring method according to claim 1, wherein the calibration information is a concentration regression equation relating to concentrations of known components in each of a plurality of solutions in which the types of dissolved components are known. 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 solution of the use solution;
The concentration measuring device according to claim 1, wherein the solution used is any one of a plurality of solutions in which the types of components dissolved therein are known. 4. The concentration measuring device according to claim 3 ,
A concentration measuring device, characterized in that 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. 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 concentration measuring device, wherein the spectrometer measures a spectroscopic spectrum of the working solution flowing through the flow path.

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