阅读说明：本技术 测定器、蚀刻系统、硅浓度测定方法及硅浓度测定程序 (Measuring device, etching system, silicon concentration measuring method, and silicon concentration measuring program ) 是由 村上友佳子 植松育生 平川雅章 于 2019-03-14 设计创作，主要内容包括：本发明提供能够测定溶液中的微量硅浓度的测定器、蚀刻系统、硅浓度测定方法及硅浓度测定程序。根据实施方式,提供一种测定器,其包含输入输出部、存储器和处理器。输入输出部被输入测定值信息,所述测定值信息表示测定对象液的磷酸、第2酸和水的浓度,所述测定对象液包含磷酸、具有比磷酸的第1酸解离指数pK<Sub>a1</Sub>小的酸解离指数pK的第2酸和水。存储器保持变动值信息,所述变动值信息包含在基准液中按照成为基准硅浓度的方式添加硅时的磷酸、第2酸和水的浓度变化与基准硅浓度的关系,所述基准液含有磷酸、第2酸和水。处理器基于输入至输入输出部的测定值信息和从存储器读出的变动值信息,得到相当于测定值信息的测定对象液的硅浓度。(The invention provides a measuring device, an etching system, a silicon concentration measuring method and a silicon concentration measuring program capable of measuring trace silicon concentration in a solution. According to an embodiment, a measuring instrument includes an input/output unit, a memory, and a processor. The input/output unit receives measurement value information indicating concentrations of phosphoric acid, 2 nd acid and water in a liquid to be measured containing phosphoric acid and having a 1 st acid dissociation index pK of phosphoric acid a1 Acid 2 of small acid dissociation index pK and water. The memory holds fluctuation value information including a relationship between a reference silicon concentration and a change in concentration of phosphoric acid, 2 nd acid and water when silicon is added to a reference liquid containing phosphoric acid, 2 nd acid and water so as to be the reference silicon concentrationAnd (3) water. The processor obtains the silicon concentration of the liquid to be measured corresponding to the measured value information based on the measured value information input to the input/output unit and the variation value information read from the memory.)

1. A measuring instrument is provided with:

an input/output unit to which measured value information indicating concentrations of phosphoric acid, a 2 nd acid and water in a liquid to be measured containing phosphoric acid and having a 1 st acid dissociation index pK higher than that of phosphoric acid is input_a1Acid 2 and water of small acid dissociation index pK;

a memory that holds fluctuation value information including a relationship between a change in concentration of the phosphoric acid, the 2 nd acid, and the water when silicon is added to a reference liquid containing the phosphoric acid, the 2 nd acid, and the water so as to become a reference silicon concentration, and the reference silicon concentration; and

and a processor for obtaining the silicon concentration of the liquid to be measured corresponding to the measured value information based on the measured value information input to the input/output unit and the fluctuation value information read from the memory.

2. The measurement instrument according to claim 1, wherein the measurement value information is obtained from an absorption spectrum of the liquid to be measured by near infrared spectroscopy.

3. The measuring instrument according to claim 1 or 2, wherein the liquid to be measured is an etching liquid for etching a silicon compound.

4. The measurement instrument according to any one of claims 1 to 3, wherein the input/output unit inputs the measurement value information and initial value information,

the initial value information indicates concentrations of the phosphoric acid, the 2 nd acid and the water in a state where the liquid to be measured does not contain silicon,

the variation information includes, as the relationship, a plurality of types of relationships between a 1 st concentration and a 2 nd concentration, and the reference silicon concentration, the 1 st concentration being concentrations of the phosphoric acid, the 2 nd acid, and the water when the silicon is added to the reference liquid so as to be the reference silicon concentration, the 2 nd concentration being a concentration of the phosphoric acid, the 2 nd acid, and the water before the silicon of the reference liquid is added,

the processor compares a concentration of the initial value information with a plurality of the 2 nd concentrations to select any one of the plurality of the 2 nd concentrations, selects the 1 st concentration corresponding to the selected 2 nd concentration, compares the selected 1 st concentration with a concentration of the measured value information, and determines the reference silicon concentration corresponding to the 1 st concentration selected based on a result of the comparison as the silicon concentration of the liquid to be measured.

5. The meter of any of claims 1-4, wherein the 2 nd acid is sulfuric acid.

6. An etching system, comprising:

a 1 st container for etching a silicon compound with an etching solution containing phosphoric acid and water;

a 2 nd container for introducing phosphoric acid into the 1 st container;

a 3 rd container for introducing water into the 1 st container;

a 4 th container for taking the etching solution from the 1 st container and containing a liquid to be measured obtained by adding sulfuric acid to the etching solution;

a measuring section provided with the measuring instrument according to any one of claims 1 to 5, for measuring a silicon concentration contained in the measurement target solution in the 4 th container; and

and a controller for introducing the phosphoric acid from the 2 nd container to the 1 st container and/or introducing the water from the 3 rd container to the 1 st container, based on a measurement result in the measuring unit.

7. A silicon concentration determination method, comprising:

from nearThe infrared spectrometer receives measurement value information indicating concentrations of phosphoric acid, 2 nd acid and water in a liquid to be measured containing the phosphoric acid and having a 1 st acid dissociation index pK higher than that of the phosphoric acid_a1The 2 nd acid and the water having a small acid dissociation index pK;

reading fluctuation value information from a memory, the fluctuation value information including a relationship between a change in concentration of the phosphoric acid, the 2 nd acid, and the water when silicon is added to a reference liquid containing the phosphoric acid, the 2 nd acid, and the water so as to be a reference silicon concentration, and the reference silicon concentration; and

obtaining the concentration of silicon contained in the measurement target solution corresponding to the received measurement value information based on the read variation value information.

8. The silicon concentration determination method according to claim 7, further comprising: receiving initial value information indicating concentrations of the phosphoric acid, the 2 nd acid and the water in a state where the liquid to be measured does not contain silicon,

wherein the variation information includes, as the relationship, a plurality of types of relationships between a 1 st concentration and a 2 nd concentration, and the reference silicon concentration, the 1 st concentration being concentrations of the phosphoric acid, the 2 nd acid, and the water when the silicon is added to the reference liquid so as to be the reference silicon concentration, the 2 nd concentration being a concentration of the phosphoric acid, the 2 nd acid, and the water before the silicon of the reference liquid is added,

comparing the concentration of the initial value information with a plurality of the 2 nd concentrations to select any one of the plurality of the 2 nd concentrations, selecting the 1 st concentration corresponding to the selected 2 nd concentration, comparing the selected 1 st concentration with the concentration of the measurement value information, and determining the reference silicon concentration corresponding to the 1 st concentration selected based on the result of the comparison as the silicon concentration of the liquid to be measured.

9. A silicon concentration measuring program for measuringDetermining the 1 st dissociation index pK of phosphoric acid_a1A silicon concentration measuring program for measuring the silicon concentration of a liquid to be measured of an acid 2 and water having a small acid dissociation index pK, wherein the program is executed by a processor,

receiving measurement value information indicating concentrations of phosphoric acid, 2 nd acid and water in a liquid to be measured containing phosphoric acid and having a 1 st acid dissociation index pK of phosphoric acid_a1Acid 2 of small acid dissociation index pK and water,

reading fluctuation value information from a memory, the fluctuation value information including a relationship between a change in concentration of the phosphoric acid, the 2 nd acid, and the water when silicon is added to a reference liquid containing the phosphoric acid, the 2 nd acid, and the water so as to become a reference silicon concentration, and the reference silicon concentration,

and calculating the concentration of silicon contained in the measurement target solution corresponding to the received measurement value information based on the read variation value information.

10. The silicon concentration measurement program according to claim 9, wherein, for the processor,

receiving the measurement value information and initial value information indicating the concentrations of the phosphoric acid, the 2 nd acid and the water in a state where the liquid to be measured does not contain silicon,

the variation information includes, as the relationship, a plurality of types of relationships between a 1 st concentration and a 2 nd concentration, and the reference silicon concentration, the 1 st concentration being concentrations of the phosphoric acid, the 2 nd acid, and the water when the silicon is added to the reference liquid so as to be the reference silicon concentration, the 2 nd concentration being a concentration of the phosphoric acid, the 2 nd acid, and the water before the silicon of the reference liquid is added,

comparing the concentration of the initial value information with a plurality of the 2 nd concentrations to select any one of the plurality of the 2 nd concentrations, selecting the 1 st concentration corresponding to the selected 2 nd concentration, comparing the selected 1 st concentration with the concentration of the measurement value information, and determining the reference silicon concentration corresponding to the 1 st concentration selected based on the result of the comparison as the silicon concentration of the liquid to be measured.

Technical Field

Embodiments of the present invention relate to a measuring device, an etching system, a silicon concentration measuring method, and a silicon concentration measuring program.

Background

In order to grasp the silicon concentration contained in the solution (particularly in the phosphoric acid solution), there are (1) an off-line analysis (ICP emission spectroscopy), and (2) a method of calculating from the amount of the dissolved silicon compound and the weight of the solution.

(1) The method (2) takes time to analyze, and cannot grasp the silicon concentration that changes in real time. The value obtained by the method (2) is a calculated value and is not actually measured.

Disclosure of Invention

The present invention addresses the problem of providing a measuring device, an etching system, a silicon concentration measuring method, and a silicon concentration measuring program, which are capable of measuring the concentration of trace silicon in a solution.

According to an embodiment, a measuring instrument includes an input/output unit, a memory, and a processor. The input/output unit receives measurement value information indicating concentrations of phosphoric acid, 2 nd acid and water in a liquid to be measured containing phosphoric acid and having a 1 st acid dissociation index pK of phosphoric acid_a1Acid 2 of small acid dissociation index pK and water. The memory holds fluctuation value information including a relationship between a change in concentration of phosphoric acid, 2 nd acid and water when silicon is added to a reference liquid containing phosphoric acid, 2 nd acid and water so as to be a reference silicon concentration, and the reference silicon concentration. The processor obtains the silicon concentration of the liquid to be measured corresponding to the measured value information based on the measured value information input to the input/output unit and the variation value information read from the memory.

According to another embodiment, an etching system includes a 1 st container, a 2 nd container, a 3 rd container, a 4 th container, a measuring section, and a control section. The 1 st container is a container for etching a silicon compound with an etching solution containing phosphoric acid and water. The 2 nd vessel is a vessel for introducing phosphoric acid into the 1 st vessel. The 3 rd vessel is a vessel for introducing water into the 1 st vessel. The 4 th container is a container for taking the etching solution from the 1 st container and accommodating a solution to be measured obtained by adding sulfuric acid to the etching solution. The measuring section includes the measuring instrument of the embodiment, and measures the silicon concentration contained in the measurement target solution in the 4 th container by using the measuring instrument. The control unit introduces phosphoric acid from the 2 nd container to the 1 st container and/or introduces water from the 3 rd container to the 1 st container, based on the measurement result in the measurement unit.

According to still another embodiment, there is provided a silicon concentration measuring method including:

receiving measurement value information from a near-infrared spectrometer, the measurement value information indicating concentrations of phosphoric acid, 2 nd acid and water in a liquid to be measured, the liquid to be measured containing phosphoric acid and having a 1 st acid dissociation index pK of phosphoric acid_a1Acid 2 and water of small acid dissociation index pK;

reading fluctuation value information from a memory, the fluctuation value information including a relationship between a change in concentration of phosphoric acid, 2 nd acid and water when silicon is added to a reference liquid containing phosphoric acid, 2 nd acid and water so as to become a reference silicon concentration, and the reference silicon concentration; and

based on the read variation information, the concentration of silicon contained in the measurement target solution corresponding to the received measurement value information is obtained.

According to still another embodiment, there is provided a silicon concentration measuring program for measuring the 1 st acid dissociation index pK of phosphoric acid-containing phosphoric acid_a1The silicon concentration of the solution to be measured of acid 2 and water having a small acid dissociation index pK. The silicon concentration measuring program is executed by using a processor, so that for the processor,

receiving measurement value information indicating concentrations of phosphoric acid, 2 nd acid and water in a liquid to be measured containing phosphoric acid and having a 1 st acid dissociation index pK of phosphoric acid_a1Acid 2 of small acid dissociation index pK and water,

reading fluctuation value information from a memory, the fluctuation value information including a relationship between a reference silicon concentration and a change in concentration of phosphoric acid, 2 nd acid and water when silicon is added to a reference liquid containing phosphoric acid, 2 nd acid and water so as to be the reference silicon concentration,

based on the read variation information, the concentration of silicon contained in the measurement target solution corresponding to the received measurement value information is calculated.

According to the measuring apparatus, the etching system, the silicon concentration measuring method, and the silicon concentration measuring program having the above-described configurations, the concentration of a trace amount of silicon in the solution can be measured.

Drawings

Fig. 1 is a block diagram of a measuring instrument according to an embodiment.

FIG. 2 is a graph showing the relationship among the concentrations of phosphoric acid, sulfuric acid and silicon with respect to the 1 st to 2 nd concentrations of phosphoric acid.

FIG. 3 is a graph showing the relationship among the phosphoric acid concentration, the sulfuric acid concentration and the silicon concentration with respect to the 1 st concentration of 3 to 5.

FIG. 4 is a graph showing the relationship among the phosphoric acid concentration, the sulfuric acid concentration and the silicon concentration with respect to the 1 st concentration of 6 to 8.

FIG. 5 is a graph showing the relationship among the phosphoric acid concentration, the sulfuric acid concentration and the silicon concentration with respect to the 1 st concentration of 9 to 10.

Fig. 6 is a functional block diagram of a processor included in the measuring instrument of fig. 1.

Fig. 7 is a flowchart showing a flow of the operation of the measuring instrument according to the embodiment.

Fig. 8 is a block diagram showing an example of an etching system according to the embodiment.

Fig. 9 is a conceptual diagram of a near-infrared light splitter in the etching system of fig. 8.

Fig. 10 is a flowchart showing a flow of silicon concentration management in the etching system of fig. 8.

Fig. 11 is a flowchart showing a flow of phosphoric acid concentration management in the etching system of fig. 8.

Fig. 12 is a block diagram showing another example of the etching system according to the embodiment.

Description of the symbols

1 measuring device, 10 input/output circuit, 11 processor, 12 ROM, 13 RAM, 14 display, 15 fluctuation value information, 16 initial value data, 17 measured value data, 18 silicon concentration measuring program, 20 initial value data acquisition part, 21 measured value data acquisition part, 22 1 st comparison part, 23 st selection part, 24 st concentration group determination part, 25 nd comparison part, 2 nd selection part, 26 nd selection part, 27 silicon concentration determination part, 31 st container, 1 st container, 32 nd container, 33 rd container, 3 near infrared spectrometer, 35 measurement part, 36 control part, 37 buffer tank, 38 supplement tank, 42 flow meter, 43 valve, 44 concentration meter, 46 etching solution, 47 silicon compound, 52 pump, 53 heater, 70 th container, and 71 th pipe.

Detailed Description

Hereinafter, embodiments will be described with reference to the drawings.

[ embodiment 1]

The measuring instrument, the method of measuring silicon concentration, and the program of measuring silicon concentration will be explained.

The measuring device is used for measuring the 1 st acid dissociation index pK containing phosphoric acid and having specific phosphoric acid_a1A measuring instrument for measuring the silicon concentration in a solution to be measured of acid 2 and water having a small acid dissociation index pK. The liquid to be measured may be a mixed liquid containing phosphoric acid, 2 nd acid and water.

The 2 nd acid may be, for example, an acid having an acid dissociation index pK of less than 2.12, and preferably an acid having an acid dissociation index pK of 1.8 or less. The acid dissociation index pK is not particularly limited, but is-15 or more according to one example.

As the 2 nd acid, for example, sulfuric acid, hydrochloric acid, nitric acid, trifluorosulfonic acid, or a mixture thereof can be used. In addition, the dissociation index pK of the 1 st acid of sulfuric acid in water at a temperature of 25 ℃ is defined_a1Is-3.0, acid dissociation index pK of sulfuric acid 2_a21.99, the acid dissociation index pK of hydrochloric acid is-8.0, the acid dissociation index pK of nitric acid is-1.3, and the acid dissociation index pK of trifluorosulfonic acid is-15.0. Note that, as the acid dissociation index, the value described on page 1 of non-patent document 1 is described.

Hereinafter, the measuring instrument according to embodiment 1 will be described with reference to fig. 1. Fig. 1 is a block diagram showing an example of the configuration of a measuring instrument according to embodiment 1.

1. Constitution of measuring instrument

The measuring instrument 1 is, for example, a general-purpose personal computer or a dedicated concentration meter incorporating a computer. Alternatively, the server may receive data from a plurality of measurement targets. The measuring instrument 1 measures the silicon concentration in the solution to be measured containing phosphoric acid, 2 nd acid, water and silicon. An example in which a mixed solution containing phosphoric acid, sulfuric acid as the 2 nd acid, silicon, and water is used as the liquid to be measured will be described below. As shown in the figure, the measuring instrument 1 includes an input/output circuit 10 as an input/output unit, a processor 11, a ROM12, a RAM13, and a display 14.

The input/output circuit 10 manages transmission and reception of information between the measuring instrument 1 and the outside. For example, in this example, when the silicon concentration is measured by the measuring instrument 1, the input/output circuit 10 is connected to the near-infrared spectrometer by wire or wirelessly, and receives various data. The input/output circuit 10 receives data input from a user or a measurement start command, for example. The ROM12 holds programs and necessary data to be executed by the processor 11. The RAM13 functions as a work area of the processor 11 and holds various data. The RAM13 holds, for example, variation value information 15, initial value data (initial value information) 16, measurement value data (measurement value information) 17, and a silicon concentration measurement program 18. The processor 11 is, for example, a CPU or the like, and calculates the silicon concentration in the solution to be measured by using the variation information 15, the initial value data (initial value information) 16, and the measurement value data (measurement value information) 17 while executing the silicon concentration measurement program 18 held in the RAM 13. Further, the display 14 displays the silicon concentration calculated by the processor 11.

Next, details of the data stored in the RAM13 and the processor 11 will be described. First, details of data stored in the RAM13 will be described.

The initial value data 16 and the measured value data 17 are information on the concentration of the liquid to be measured which is an actual measurement target.

The measured value data 17 is measured value information including a phosphoric acid concentration (wt%), a sulfuric acid concentration (wt%), and a water concentration (wt%) of the liquid to be measured by the near-infrared spectroscopy. These values are input to the input/output circuit 10 at the time of measurement.

The initial value data 16 is information including a phosphoric acid concentration (wt%), a sulfuric acid concentration (wt%), and a water concentration (wt%) in a state before the measurement of the measured value data 17 and before the silicon is contained in the liquid to be measured. That is, the initial value data 16 can be said to be initial values of the phosphoric acid concentration, the sulfuric acid concentration, and the water concentration of the liquid to be measured. The initial value data 16 is supplied to the input/output circuit 10 before the silicon is mixed in the liquid to be measured. The initial value data 16 may be an actual measurement value obtained by near infrared spectroscopy or the like, or may be obtained by calculation such as simulation. The initial value data 16 can be used as a control value or a target value of the concentration of the liquid to be measured. As an example of the use of the liquid to be measured, an etching liquid used for etching treatment can be mentioned.

The variation value information 15 is not concentration information of the liquid to be measured itself, but information of the 1 st reference liquid and the 2 nd reference liquid used for determining the silicon concentration of the liquid to be measured. The 2 nd reference liquid is a mixed liquid containing phosphoric acid, sulfuric acid as the 2 nd acid, and water, and containing no silicon. Specifically, the variation value information 15 indicates the relationship between the 1 st concentration, which is the concentration of phosphoric acid, sulfuric acid and water in the 1 st reference liquid to which silicon is added in the 2 nd reference liquid so as to become the reference silicon concentration, and the 2 nd concentration, which is the concentration of phosphoric acid, sulfuric acid and water in the 2 nd reference liquid to which silicon is not added, and the reference silicon concentration. The variation information 15 includes a correspondence relationship between the 1 st and 2 nd concentrations of the plurality of patterns and the reference silicon concentration. The 1 st concentration and the 2 nd concentration are obtained by, for example, measurement with a near infrared spectrometer. The variation information 15 is provided by a near-infrared spectrometer before the silicon concentration of the liquid to be measured is measured. Table 1 shows an example of the concept of the 2 nd concentration.

[ Table 1]

In the examples of table 1, 2 nd concentration examples of phosphoric acid, sulfuric acid and water of 2 nd reference liquid measured by a near infrared spectrometer are shown. As shown in table 1, there are a plurality of (4 in table 1) modes of the 2 nd concentration, specifically, the concentration (% by weight) of phosphoric acid, sulfuric acid and water measured by a near-infrared spectrometer in the 2 nd reference solution. The number of the 2 nd concentration patterns is not limited to 4, and may be adjusted according to the use of the liquid to be measured, and may be set to 1 or 2 or more.

The 1 st concentration is the concentration (wt%) of phosphoric acid, sulfuric acid and water measured by a near infrared spectrometer of a 1 st reference liquid obtained by mixing silicon in a 2 nd reference liquid satisfying the 2 nd concentration at a reference silicon concentration. When silicon is added to the 2 nd reference liquid, the concentrations of phosphoric acid, sulfuric acid and water vary from the 2 nd concentration. The fluctuation range is changed by the influence of the added concentration of silicon. Table 2 and fig. 2 to 5 show an example of the concept of the relationship between the 1 st concentration and the reference silicon concentration. When 50ppm and 150ppm of silicon were mixed in a plurality of 2 nd reference liquids having the 2 nd concentration 1 shown in Table 1, the 1 st concentration (% by weight) of phosphoric acid, sulfuric acid and water measured by a near infrared spectrometer was 1 st to 2 nd. The 1 st concentration 3-5 is the 1 st concentration (wt%) of phosphoric acid, sulfuric acid and water measured by a near infrared spectrometer when mixing 50ppm, 70ppm and 150ppm of silicon in a plurality of 2 nd reference liquids having the 2 nd concentration 2. The 1 st concentrations 6 to 8 are 1 st concentrations (wt%) of phosphoric acid, sulfuric acid and water measured by a near infrared spectrometer when 50ppm, 70ppm and 150ppm of silicon are mixed in a plurality of 2 nd reference liquids having the 2 nd concentration 3. Further, the 1 st concentrations 9 to 10 are the 1 st concentrations (wt%) of phosphoric acid, sulfuric acid and water measured by a near infrared spectrometer when 50ppm and 150ppm of silicon are mixed in a plurality of 2 nd reference liquids having the 2 nd concentration.

[ Table 2]

FIG. 2 shows the relationship between the concentration (% by weight) of phosphoric acid and the concentration (% by weight) of sulfuric acid and the concentration (ppm) of Si in the 1 st concentration 1-2.

FIG. 3 shows the relationship between the concentration (% by weight) of phosphoric acid and the concentration (% by weight) of sulfuric acid and the concentration (ppm) of Si in the 1 st concentrations 3 to 5.

FIG. 4 shows the relationship between the concentration (% by weight) of phosphoric acid and the concentration (% by weight) of sulfuric acid and the concentration (ppm) of Si in the 1 st concentrations 6 to 8.

FIG. 5 shows the relationship between the concentration (% by weight) of phosphoric acid and the concentration (% by weight) of sulfuric acid and the concentration (ppm) of Si in the 1 st concentration range from 9 to 10.

That is, as shown in fig. 2 to 5, when silicon is added to the 2 nd reference liquid, the ratio of phosphoric acid, sulfuric acid, and water varies. Various patterns exist for the degree of this variation. The variation value information 15 can be said to be information of a plurality of patterns regarding the manner of variation of the ratio thereof. In the examples of table 1 and table 2 and fig. 2 to fig. 5, the cases of 2 to 3 modes are shown, but 1 mode may be used, or information of 4 modes or more may be held. Instead of being obtained by measurement by near-infrared spectroscopy as described above, the variation information 15 may be obtained by calculation such as simulation.

Next, the processor 11 will be described in detail. The processor 11 functions to calculate the silicon concentration in the liquid to be measured in which the silicon is mixed by executing a silicon concentration measurement program. Fig. 6 is a functional block diagram of the processor 11 when the silicon concentration measurement program 18 is executed.

As shown in fig. 6, the processor 11 executes the silicon concentration measurement program 18 to function as an initial value data acquisition unit 20, a measured value data acquisition unit 21, a 1 st comparison unit 22, a 1 st selection unit 23, a 1 st concentration group determination unit 24, a 2 nd comparison unit 25, a 2 nd selection unit 26, and a silicon concentration determination unit 27.

The initial value data acquisition unit 20 acquires the initial value data 16 via the input/output circuit 10. The measurement value data acquisition unit 21 acquires the measurement value data 17 from the near-infrared spectrometer. The 1 st comparing unit 22 compares the 2 nd density described by way of example in table 1 with the acquired initial value data 16. The 1 st selector 23 selects any of the 2 nd concentrations exemplified in table 1 based on the comparison result in the 1 st comparator 22. The 1 st concentration group determining unit 24 determines a 1 st concentration group corresponding to the selected 2 nd concentration among the plurality of 1 st concentrations described by taking table 2 as an example. The 2 nd comparing section 25 compares the determined 1 st concentration group with the acquired measurement value data 17. The 2 nd selection section 26 selects any 1 st concentration from the 1 st concentration group based on the comparison result in the 2 nd comparison section 25. The silicon concentration determination unit 27 determines the silicon concentration in the measurement target solution based on the 1 st concentration selected by the 2 nd selection unit 26. The determined silicon concentration is then displayed in the display 14.

2. Operation of the measuring device

Next, the operation of the measuring instrument of the embodiment will be described.

First, the flow of the entire operation will be described with reference to fig. 7. Fig. 7 is a flowchart showing the overall flow of the operation of the measuring instrument. In fig. 7, an example in which the liquid to be measured is an aqueous solution containing phosphoric acid and sulfuric acid will be described. First, the initial value data acquisition unit 20 of the processor 11 receives the 2 nd concentration of the liquid to be measured, which is in a state before mixing silicon and is composed of the phosphoric acid concentration, the sulfuric acid concentration, and the water concentration, in the input/output circuit 10, and holds the received concentration in the RAM13 as the initial value data 16 (step S1). The variation information 15 may be held in advance in the RAM13 before step S1, or may be stored in the RAM13 after step S1.

After that, silicon is mixed into the liquid to be measured, and the phosphoric acid concentration, the sulfuric acid concentration, and the water concentration of the liquid to be measured are measured by a near-infrared spectrometer to obtain an absorption spectrum.

Then, when the input/output circuit 10 of the measuring instrument 1, for example, receives a measurement command of the silicon concentration in the measurement target solution (step S2), the measurement value data acquiring unit 21 of the processor 11 receives the 1 st concentration of the measurement target solution in which silicon is mixed, which is formed of the phosphoric acid concentration, the sulfuric acid concentration, and the water concentration, in the input/output circuit 10 and holds the received concentration in the RAM13 as the measurement value data 17 (step S3).

Next, the 1 st comparing section 22 of the processor 11 compares the initial value data 16 obtained in step S1 with the 2 nd density of the variation value information 15 held in the RAM 13. Specifically, the 1 st comparing section 22 compares the 2 nd concentrations 1 to 4 shown in table 1 as the 2 nd concentration example with the initial value data 16, that is, the concentrations of phosphoric acid, sulfuric acid and water in the liquid to be measured in a state before silicon mixing. Then, the 1 st selection part 23 selects the 2 nd density whose result of comparison in the 1 st comparison part 22 is closest to (or the same as) (step S4). Assume that the 2 nd concentration 1 is selected by the 1 st selection part 23, for example.

Next, the 1 st concentration group determining unit 24 determines the 1 st concentration group corresponding to the selected 2 nd concentration 1 in the variation value information 15 held in the RAM13 (step S5). In the case of table 2, the 1 st concentration 1 and the 1 st concentration 2 correspond to the 1 st concentration group corresponding to the 2 nd concentration 1.

The 2 nd comparing unit 25 compares the measured value data 17 obtained in step S3 with the 1 st concentration 1 and the 1 st concentration 2 obtained in step S5. Then, the 2 nd selection part 26 selects the 1 st concentration whose result of comparison in the 2 nd comparison part 25 is closest to (or the same as) (step S6). Of the 1 st concentration 1 and the 1 st concentration 2, the 1 st concentration selected in step S6 is set to the 1 st concentration 1. As shown in table 2, the 1 st concentration 1 corresponds to the phosphoric acid concentration, the sulfuric acid concentration, and the water concentration of the 1 st reference liquid obtained by adding silicon to the 2 nd reference liquid satisfying the 2 nd concentration 1 so that the concentration thereof becomes 50 ppm. The measured value data 17 of the liquid to be measured is the same as or closest to the 1 st concentration 1. Therefore, the silicon concentration determination unit 27 determines that the silicon concentration of the measurement target liquid is 50ppm (step S7).

The 2 nd comparing unit 25 and the 2 nd selecting unit 26 may calculate the silicon concentration by, for example, linear approximation. That is, the silicon concentrations shown in table 2 have discrete values. However, these discrete values may be used as in the graphs shown by the broken lines and the solid lines in fig. 2 to 5, and may be obtained by linear approximation.

For example, the initial value data 16 obtained in step S1 is set to the 2 nd concentration 2, and the measured value data 17 obtained in step S3 is set to the following values.

Phosphoric acid concentration: 85.41% by weight

Sulfuric acid concentration: 1.53% by weight

Water concentration: 13.06% by weight

So that their values approximately coincide with the line shapes shown in fig. 3. The value of each concentration is approximately intermediate between the value in the case where the silicon concentration is 70[ ppm ] and the value in the case where the silicon concentration is 150[ ppm ]. Therefore, the silicon concentration in this case can be estimated to be about 110[ ppm ]. These calculations may be performed by any of the 2 nd comparing unit 25, the 2 nd selecting unit 26, and the silicon concentration determining unit 27.

Through the above steps, the silicon concentration of the liquid to be measured containing phosphoric acid, sulfuric acid as the 2 nd acid, and water is measured. Therefore, according to the measuring instrument of the embodiment, the silicon concentration in the solution to be measured can be obtained from the concentration change of the phosphoric acid and the 2 nd acid before and after mixing the silicon in the solution to be measured including the phosphoric acid, the 2 nd acid, and the water. Therefore, the measuring instrument of the embodiment can measure the silicon concentration of an extremely small amount of the inevitable impurity level. Such a trace silicon concentration cannot be measured by any of a specific gravity measurement method such as near infrared spectroscopy, a molybdenum yellow absorbance method, and an electrical conductivity measurement method. In the case of the specific gravity measurement method, the concentration of silicon mixed in the liquid to be measured is too low to detect a change in specific gravity. In the molybdenum yellow absorbance method, the absorption derived from silicon and the absorption derived from phosphoric acid overlap and cannot be separated, and therefore, the silicon concentration cannot be measured.

Further, according to the measuring instrument of the embodiment, since the time required for measurement can be shortened, the silicon concentration which varies in real time due to the etching process or the like can be grasped.

The measuring instrument according to the embodiment may further include a near-infrared spectrometer. The near-infrared spectrometer can measure the concentrations of phosphoric acid, sulfuric acid, and water in a solution to be measured with high accuracy and with ease by absorption spectroscopy, and therefore can obtain the silicon concentration in the solution to be measured with high accuracy.

Alternatively, instead of using the actual measurement value for the reference silicon concentration, the processor 11 may calculate the silicon concentration of the measurement target liquid after mixing silicon based on the concentrations of phosphoric acid, sulfuric acid, and water in the measurement target liquid before mixing silicon and the concentrations of phosphoric acid, sulfuric acid, and water in the measurement target liquid after mixing silicon, and use the calculated value as the reference silicon concentration.

[ 2 nd embodiment ]

An etching system is explained. The etching system is a system for etching a silicon compound with an etching solution containing phosphoric acid and water. The silicon compound may be, for example, a film of a silicon compound formed on a substrate. Examples of the substrate include a SiC substrate, a GaN substrate, and the like. An etching system according to an embodiment will be described with reference to fig. 8.

1. Constitution of etching system

The etching system shown in fig. 8 includes a 1 st container (etching processing unit) 31 for etching a silicon compound with an etching liquid containing phosphoric acid and water, a 2 nd container (phosphoric acid supply unit) 32 for introducing phosphoric acid into the 1 st container 31, a 3 rd container (water supply unit) 33 for introducing water into the 1 st container 31, a near infrared spectrometer 34, a measurement unit 35 for measuring a silicon concentration contained in a sample liquid (liquid to be measured), and a control unit 36. The near-infrared spectrometer 34 includes a 4 th container (not shown in fig. 8) for collecting the etching solution from the 1 st container 31 and containing a sample solution obtained by adding sulfuric acid to the etching solution. Fig. 9 shows an example of the 4 th container. The measuring unit 35 used in the measuring apparatus according to embodiment 1. The controller 36 controls the whole etching system. Further, the control unit 36 introduces phosphoric acid in the 2 nd container 32 into the 1 st container 31 and/or introduces water in the 3 rd container 33 into the 1 st container 31, based on the measurement result by the measuring unit 35. In fig. 8, for the sake of convenience of illustration, the control unit 36 is electrically connected to only the 1 st container 31 and the 2 nd container 32, but is electrically connected to each part constituting the etching system, and signals can be exchanged between the control unit 36 and each part.

A buffer tank 37 and a replenishment tank 38 are disposed in the path from the 2 nd vessel 32 and the 3 rd vessel 33 to the 1 st vessel 31. The 2 nd vessel 32 and the 3 rd vessel 33 are connected to the buffer tank 37 via a 1 st pipe 39 and a 2 nd pipe 40, respectively. The buffer tank 37 is connected to the replenishment tank 38 via a 3 rd pipe 41. The flowmeter 42 and the valve 43 are provided in this order from the upstream side of the 3 rd pipe 41. The concentration meter 44 is connected to the replenishment tank 38 via a 4 th pipe 45.

An etching solution 46 containing phosphoric acid and water is contained in the 1 st container 31. The etching solution 46 is immersed in the silicon compound 47 to perform etching treatment on the silicon compound 47. The etching solution 46 overflowing from the 1 st container 31 during the etching process is temporarily stored in the storage tank 48. The storage tank 48 is connected to the replenishment tank 38 via a 5 th pipe 49. A filter (not shown) is provided in the 5 th pipe 49. The filter removes foreign substances contained in the etching solution. The etching solution 46 overflowing from the 1 st container 31 during the etching process is collected in the storage tank 48, and then passes through a filter from the storage tank 48 and is stored in the replenishment tank 38 via the 5 th pipe 49. The storage tank 48 is also connected to a drain pipe 50. The replenishment tank 38 is connected to the 1 st vessel 31 via a 6 th pipe 51. The pump 52 and the heater 53 are provided in this order from the upstream side of the 6 th pipe 51. Here, a system including a path from the replenishment tank 38 to the 1 st container (etching processing unit) 31 and a path from the 1 st container 31 to the replenishment tank 38 via the storage tank 48 is referred to as an etching processing system. The etching system includes piping and the like in the passage, in addition to the 1 st container 31, the replenishment tank 38, and the storage tank 48.

The etching processing system is filled with an etching solution 46 containing phosphoric acid and water. In the etching treatment, since the capacity of the etching liquid 46 is decreased by the evaporation of water and the phosphoric acid concentration is increased, or the phosphoric acid concentration is decreased by the consumption of phosphoric acid, etc., it is necessary to control the phosphoric acid concentration in the etching liquid 46. The phosphoric acid concentration of the etching solution 46 in the etching processing system is measured by the concentration meter 44, and when the phosphoric acid concentration deviates from the control value, a signal is sent to the control unit 36. Upon receiving the signal, the controller 36 adjusts the amount of phosphoric acid supplied from the 2 nd tank 32 to the buffer tank 37 and the amount of water supplied from the 3 rd tank 33 to the buffer tank 37 to prepare phosphoric acid water having a predetermined concentration as a replenishment solution. The replenishment liquid in the buffer tank 37 is supplied to the etching processing system while opening the valve 43 and adjusting the supply amount by the flow meter 42. The phosphoric acid concentration of the etching solution 46 in the etching system can be set within the control value by controlling the phosphoric acid concentration of the replenishment solution and the amount of the replenishment solution supplied from the buffer tank 37 to the etching system. In order to increase the phosphoric acid concentration of the etching liquid 46, the phosphoric acid concentration of the replenishment liquid may be increased, or the amount of the replenishment liquid supplied from the buffer tank 37 to the etching system may be decreased. On the other hand, in order to reduce the phosphoric acid concentration of the etching liquid 46, the phosphoric acid concentration of the replenishment liquid is reduced, and the amount of the replenishment liquid supplied from the buffer tank 37 to the etching system is increased. The amount of the replenishment liquid supplied from the buffer tank 37 to the etching system may be adjusted by adjusting the opening amount of the valve 43 while monitoring the supply amount with the flow meter 42.

When the control values of the phosphoric acid concentration and the water concentration are changed by changing the etching conditions such as the phosphoric acid concentration, the water concentration, the temperature, and the like of the etching liquid 46, a signal is sent to the control unit 36, and the control unit 36 resets the control values of the phosphoric acid concentration and the water concentration of the etching liquid 46 to set new control values.

The etching system may be provided with a water supply tank for supplying evaporated water to the 1 st container 31, separately from the 3 rd container 33.

The etching system may be provided with a concentration meter for directly measuring the phosphoric acid concentration of the etching solution 46 in the 1 st container 31 instead of the concentration meter 44 or separately from the concentration meter 44.

Fig. 9 is a schematic block diagram of the near-infrared beam splitter 34. As shown in the figure, the near-infrared spectrometer 34 includes a test container 60 as a 4 th container, a light source 61, a spectrometer 62, a calculator 63, and a temperature controller 64.

The test container 60 is, for example, a container transparent to near infrared light. The test container 60 is supplied with the etching solution 46 from the 1 st container 31 for etching the silicon compound and with sulfuric acid from a sulfuric acid supply unit different from the 1 st container 31. As a result, the sample liquid obtained by adding sulfuric acid to the etching liquid 46 in which silicon is dissolved in the test container 60 is purified as a liquid to be measured. The supply rates and supply timings of the etching liquid 46 and the sulfuric acid are controlled by the controller 36, for example. The temperature of the sample liquid (liquid to be measured) in the test container 60 is controlled by a temperature controller 64. In order to improve the measurement accuracy of the measurement by the near-infrared spectroscopy, the temperature of the sample liquid is preferably controlled to room temperature or lower.

The light source 61 generates near-infrared light, and the generated near-infrared light passes through the test container 60.

The spectroscope 62 obtains an absorption spectrum of the sample liquid (liquid to be measured) by spectroscopically separating the near-infrared light having passed through the test container 60.

The calculator 63 calculates the phosphoric acid concentration, the sulfuric acid concentration, and the water concentration of the sample liquid (the liquid to be measured) based on the absorption spectrum obtained by the spectroscope 62, and outputs the results to the measurement unit 35. That is, the initial value data 16 and the measured value data 17 described in fig. 1 of embodiment 1 are supplied from the calculator 63 to the measuring unit 35. Further, the 2 nd concentration and the 1 st concentration may be generated by information from the calculator 63.

2. Actions of the etching System

The operation of the etching system will be described with reference to fig. 10 and 11. Fig. 10 is a flowchart showing a flow of silicon concentration management in the etching system. On the other hand, fig. 11 is a flowchart showing the control of the phosphoric acid concentration in the etching system.

Regarding phosphoric acid concentration management

The initial values of the phosphoric acid concentration, the sulfuric acid concentration, and the water concentration of the etching solution 46 in the etching system are inputted to the measuring section 35. The initial values of the phosphoric acid concentration and the water concentration are concentrations suitable for the predetermined etching process conditions, and are measured by, for example, a concentration meter 44. The etching liquid 46 used in the etching treatment in the system shown in fig. 8 is an aqueous phosphoric acid solution and does not contain sulfuric acid. Sulfuric acid is added to the sample solution to be measured by the near-infrared spectrometer 34 in order to improve the accuracy of the silicon concentration measurement. The sulfuric acid concentration suitable for the measurement of the silicon concentration may vary depending on the phosphoric acid concentration and the water concentration. Therefore, the initial value of the etching liquid 46 includes sulfuric acid concentrations corresponding to the phosphoric acid concentration and the water concentration in addition to the phosphoric acid concentration and the water concentration. The input initial value is held in the RAM13 as initial value data 16. The measuring unit 35 calculates the ratio of phosphoric acid to water based on the phosphoric acid concentration and the water concentration of the initial values, and transmits the calculated ratio as a control value to the control unit 36 (step S20).

The etching processing system is filled with the etching solution 46 having a ratio of phosphoric acid to water within a control value (step S21). The ratio of phosphoric acid to water in the etching liquid 46 of the etching system is measured by the concentration meter 44 (step S22). When the ratio of phosphoric acid to water in the etching liquid 46 in the etching treatment system is within the control value (Yes in step S23), the etching treatment is performed while measurement is performed by the concentration meter 44 at regular intervals.

When the ratio of phosphoric acid to water in the etching liquid 46 of the etching processing system deviates from the control value (No in step S23), a signal is sent to the control unit 36. Upon receiving the signal, the control unit 36 adjusts the amount of phosphoric acid supplied from the 2 nd tank 32 to the buffer tank 37 and the amount of water supplied from the 3 rd tank 33 to the buffer tank 37 to prepare phosphoric acid water having a predetermined concentration as a replenishment liquid (step S24). The replenishment liquid in the buffer tank 37 is supplied to the etching processing system while the valve 43 is opened and the supply amount is adjusted by the flow meter 42 (step S25). The ratio of phosphoric acid to water for the preparation (preparation) of the replenishment solution and the supply of the etching solution 46 to the etching treatment system falls within the control values.

For silicon concentration determination

The silicon concentration measurement command is sent to the control unit 36 every time a predetermined time elapses from the start of the etching process. The controller 36 collects a part of the etching liquid 46 in the etching system into the test container 60 to obtain a sample liquid (step S11). As described above, the etching liquid 46 does not contain sulfuric acid (No in step S12). Then, the control unit 36 adds sulfuric acid to the sample solution so as to have a predetermined concentration, thereby obtaining a solution to be measured (step S13). Next, the near-infrared spectrometer 34 measures the phosphoric acid concentration, the sulfuric acid concentration, and the water concentration of the liquid to be measured in the test container 60 (step S14). The obtained measurement result is input to the measurement unit 35, and is held in the RAM13 as measurement value data 17.

The control unit 36 transmits a signal to the measuring unit 35, and the 1 st comparing unit 22 in the measuring unit 35 compares the 2 nd density of the variation information 15 of the RAM13 with the initial value data 16. The 1 st comparing section 22 selects any 2 nd concentration from the plurality of 2 nd concentrations based on the comparison result. The 1 st concentration group determining unit 24 in the measuring unit 35 determines a group including the 1 st concentration corresponding to the selected 2 nd concentration in the 1 st concentration fluctuation value information 15. The 2 nd comparing section 25 in the measuring section 35 compares the determined 1 st concentration group with the acquired measurement value data 17. The 2 nd selection unit 26 in the measurement unit 35 selects any 1 st concentration from the 1 st concentration group based on the comparison result in the 2 nd comparison unit 25. The silicon concentration determination unit 27 in the measurement unit 35 determines the reference silicon concentration corresponding to the 1 st concentration selected by the 2 nd selection unit 26 as the silicon concentration in the measurement target solution. Then, the measurement unit 35 causes the display 14 to display the determined silicon concentration (step S15). The details of the processing in step S15 are as described in embodiment 1 with reference to fig. 7.

When the silicon concentration calculated in step S15 deviates from the control value (No in step S16), the controller 36 sends a signal to discharge the etching liquid 46 in the storage tank 48 to the outside of the system through the drain pipe 50 (step S17). The control unit 36 also sends signals to adjust the amount of phosphoric acid supplied from the 2 nd tank 32 to the buffer tank 37 and the amount of phosphoric acid supplied from the 3 rd tank 33 to the buffer tank 37 to prepare phosphoric acid water of a predetermined concentration as a replenishment liquid (step S18).

Next, the control unit 36 sends a signal to supply the replenishment liquid in the buffer tank 37 to the etching processing system while opening the valve 43 and adjusting the supply amount by the flow meter 42 (step S19). As a result, the silicon concentration in the etching solution in the etching processing system is set within the control value.

Thereafter, a silicon concentration measurement command is transmitted to the control unit 36, and the sample liquid is collected again (step S11).

According to the etching system described above, since the concentration of silicon present in a trace amount in the etching solution can be measured, the concentration of silicon that varies due to the etching process can be grasped in real time.

The etching system is not limited to a system using an etching solution containing no sulfuric acid, and may be a system containing sulfuric acid in the etching solution. An example of this is shown in fig. 12. The etching system shown in fig. 12 has the same configuration as the etching system shown in fig. 8 except that it includes a 5 th vessel 70 for introducing sulfuric acid into the 1 st vessel 31 and a 7 th pipe 71 for connecting the 5 th vessel 70 to the buffer tank 37. In the silicon concentration management in the etching system shown in fig. 12, since the etching liquid 46 contains sulfuric acid in advance, the step of adding sulfuric acid to the sample liquid before the measurement by the near-infrared spectrometer 34 (step S13) may be omitted, or the step of adding sulfuric acid to the sample liquid may be performed in order to set the sulfuric acid concentration in the sample liquid to a concentration suitable for the measurement (step S13) when the sulfuric acid concentration in the sample liquid is low. When the sulfuric acid concentration in the sample solution is high, a step of adding phosphoric acid and/or water to the sample solution to reduce the sulfuric acid concentration is performed.

In the above embodiment, a case where a function of calculating the silicon concentration is installed in software is described as an example. However, it may be installed in hardware, or may be installed in a combination of software and hardware. In the case of installation in software, the functions thereof may be stored in or transmitted through a storage medium that can be read by a computer as 1 or more commands or codes. Such a recording medium is not particularly limited as long as it can be accessed by a computer or a processor. As an example, an optical disk such as a RAM, a ROM, an EEPROM (registered trademark) (including a USB memory or a memory card), a CD-ROM, or a magnetic disk such as a hard disk can be used.

In addition, in the above-described embodiment, the case where the 2 nd density (table 1) and the 1 st density (table 2) are handled as separate information was described as an example, but they may be data set as one. That is, as described above, tables 1 and 2 are tables for selecting any 1 st concentration included therein and obtaining the silicon concentration based on the reference silicon concentration corresponding to the selected 1 st concentration. Therefore, it is not necessary that table 1 and table 2 are different from each other, and the method is not limited to the method described in table 1 and table 2, and the 1 st concentration may be selected based on the measurement value data 17. For example, the ratio of phosphoric acid, sulfuric acid, and water in the case where no silicon is contained, the silicon concentration, and the amount of change in the ratio of phosphoric acid, sulfuric acid, and water in the case where silicon is dissolved may be maintained.

Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments may be implemented in other various ways, and various omissions, substitutions, and changes may be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.