TW202009451A - Measuring device, etching system, method for measuring silicon concentration and program for measuring silicon concentration including an input and output unit, a memory, and a processor - Google Patents

Abstract

The present invention provides a measuring device, an etching system, a method for measuring silicon concentration, and a program for measuring silicon concentration, which can measure trace silicon concentration in a liquid. According to one embodiment, a measuring device including an input and output unit, a memory, and a processor is provided. The information of measured values of the concentration of phosphoric acid, a second acid and water of a to-be-measured liquid, including phosphoric acid, the second acid having an acid dissociation constant pK that is smaller than the first acid dissociation constant pKa1 of the phosphoric acid, and water, is input into and displayed by the input and output unit. The memory keeps variable value information, and the variable value information includes the relationship between changes in the concentration of phosphoric acid, the second acid, and water when silicon is added to a reference solution including phosphoric acid, the second acid, and water in a manner for forming a reference silicon concentration, and the reference silicon concentration. The processor obtains a silicon concentration of the to-be-measured liquid equivalent to the information of measured values based on the information of measured values input into the input and output unit and the variable value information read from the memory.

Description

Measuring instrument, etching system, silicon concentration measuring method and silicon concentration measuring program

The embodiment of the present invention relates to a measuring instrument, an etching system, a silicon concentration measuring method, and a silicon concentration measuring program.

In order to grasp the concentration of silicon contained in the liquid (especially the phosphoric acid solution), there are (1) off-line analysis (ICP emission spectrometry), (2) methods based on the amount of dissolved silicon compound and the weight of the liquid.

(1) The method consumes time during analysis and cannot grasp the silicon concentration that changes in real time. Moreover, the value obtained by the method of (2) is a calculated value rather than an actual measured value.

The problem to be solved by the present invention is to provide a measuring device, an etching system, a silicon concentration measuring method and a silicon concentration measuring program that can measure the trace silicon concentration in a liquid.

According to an embodiment, a measuring device including an input/output unit, a memory, and a processor is provided. The input/output unit displays the measurement of the concentration of phosphoric acid, second acid, and water containing phosphoric acid, the second acid having a dissociation constant pK _{a1 which} is smaller than the phosphoric acid, and the second acid having a dissociation constant pK, and water. Value information. The memory maintains the change value information, which includes the concentration change of the phosphoric acid, the second acid, and the water when the silicon is added to the reference liquid containing phosphoric acid, the second acid, and water so as to become the reference silicon concentration and the reference silicon Concentration relationship. The processor obtains the silicon concentration of the measurement target liquid equivalent to the measured value information based on the measured value information input to the input/output unit and the variable value information read out from the memory.

According to another embodiment, an etching system including a first container, a second container, a third container, a fourth container, a measurement unit, and a control unit is provided. The first container is used for etching silicon compounds using an etching solution containing phosphoric acid and water. The second container is for introducing phosphoric acid into the first container. The third container is for introducing water into the first container. The fourth container is used for acquiring an etching solution from the first container and containing a measurement target liquid obtained by adding sulfuric acid to the etching solution. The measuring section includes the measuring instrument of the embodiment, and the measuring instrument measures the silicon concentration contained in the measurement target liquid in the fourth container. The control unit introduces phosphoric acid from the second container into the first container and/or introduces water from the third container into the first container according to the measurement result of the measurement unit.

According to yet another embodiment, there is provided a method for measuring silicon concentration, which comprises: receiving from a near-infrared beam splitter a phosphoric acid, a second acid having a first acid dissociation constant pK _{a1 which} is smaller than the phosphoric acid, and a second acid having a smaller acid dissociation constant pK; and The measured value information of the concentration of phosphoric acid, the second acid, and water in the measurement target liquid of water; read out the variable value information from the memory. The variable value information includes the reference liquid containing phosphoric acid, the second acid, and water to become Reference silicon concentration method The relationship between the concentration change of phosphoric acid, the second acid, and water when adding silicon and the reference silicon concentration; based on the reading of the change value information, the measurement target liquid equivalent to the received measurement value information is obtained The concentration of silicon.

Further, according to still another embodiment, there is provided a silicon concentration for measuring a silicon concentration of a measurement target liquid containing phosphoric acid, a second acid having an acid dissociation constant pK _{a1 which} is smaller than the phosphoric acid first acid dissociation constant pK _a1 , and water Determination program. The silicon concentration measurement program is executed by the processor to cause the processor to receive the phosphoric acid, the second acid which contains phosphoric acid, the first acid dissociation constant pKa1 which is smaller than the phosphoric acid dissociation constant pK1, and the water to be measured, The measured value information of the concentration of the second acid and water; the variable value information is read from the memory, and the variable value information includes when adding silicon to the reference solution containing phosphoric acid, the second acid, and water so as to become the reference silicon concentration The relationship between the concentration change of phosphoric acid, second acid, and water and the reference silicon concentration; based on the read change value information, calculate the concentration of silicon contained in the measurement target liquid equivalent to the received measurement value information.

According to the measuring instrument, etching system, silicon concentration measuring method and silicon concentration measuring program constructed as above, the trace silicon concentration in the liquid can be measured.

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

[First Embodiment] A measuring device, a silicon concentration measuring method, and a silicon concentration measuring program will be described.

The measuring instrument is used to measure the concentration of silicon in the liquid to be measured including phosphoric acid, a second acid having a dissociation constant pK _{a1 which} is smaller than the phosphoric acid and an acid dissociation constant pK, and water. The liquid to be measured may be a mixed liquid containing phosphoric acid, the second acid, and water.

Examples of the second acid include acids having an acid dissociation constant pK of less than 2.12, preferably acids of 1.8 or less. There is no particular lower limit for the acid dissociation constant pK, but it is -15 or more according to an example.

As the second acid, for example, sulfuric acid, hydrochloric acid, nitric acid, trifluoromethanesulfonic acid, or a mixture thereof can be used. In addition, in water at a temperature of 25°C, the first acid dissociation constant pK _a1 of sulfuric acid is -3.0, the second acid dissociation constant pK _a2 of sulfuric acid is 1.99, the acid dissociation constant pK of hydrochloric acid is -8.0, and the acid dissociation constant of nitric acid pK is -1.3, and the acid dissociation constant of trifluoromethanesulfonic acid pK is -15.0. In addition, as the acid dissociation constant, the value described on page 1 of Non-Patent Document 1 is described.

Hereinafter, the measuring device of the first embodiment will be described with reference to FIG. 1. FIG. 1 is a block diagram showing a configuration example of the measuring device according to the first embodiment.

1. Composition of the measuring device The measuring device 1 is a dedicated concentration meter incorporating, for example, a general-purpose personal computer or a computer. Or, it may be a server that receives data from a plurality of measurement objects. Then, the measuring device 1 measures the silicon concentration in the liquid to be measured including phosphoric acid, the second acid, water, and silicon. An example of using a mixed liquid containing phosphoric acid, sulfuric acid as a second acid, silicon, and water as the measurement target liquid will be described below. As shown in the figure, the measuring device 1 includes an input/output circuit 10 as an input/output unit, a processor 11, a ROM 12, a RAM 13, and a display 14.

The input/output circuit 10 manages the transmission and reception of information between the measuring device 1 and the outside. For example, in this example, when measuring the silicon concentration by the measuring device 1, the input/output circuit 10 is connected to the near-infrared beam splitter by wire or wirelessly to receive various data. In addition, the input/output circuit 10 accepts, for example, data input from the user and a command to start measurement. The ROM 12 holds programs executed by the processor 11 and required data. The RAM 13 functions as an operation area of the processor 11 and holds various data. The RAM 13 holds, for example, variable value information 15, initial value data (initial value information) 16, measured value data (measured value information) 17, and silicon concentration measurement program 18. The processor 11 is, for example, a CPU or the like, executes the silicon concentration measurement program 18 held by the RAM 13 and calculates the measurement target liquid using the variable value information 15, the initial value data (initial value information) 16 and the measured value data (measured value information) 17 The concentration of silicon in. Furthermore, the display 14 displays the silicon concentration calculated by the processor 11.

Next, the details of the data held in the RAM 13 and the processor 11 will be described. First, the details of the data held in the RAM 13 will be described.

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

The measured value data 17 includes measured value information of phosphoric acid concentration (wt%), sulfuric acid concentration (wt%), and water concentration (wt%) obtained by the near-infrared spectroscopy of the measurement object liquid. These values are input to the input/output circuit 10 during measurement.

In addition, the initial value data 16 is obtained before the measurement of the measured value data 17, and includes information on the phosphoric acid concentration (wt%), sulfuric acid concentration (wt%), and water concentration (wt%) in the state before the measurement object liquid contains silicon . That is, the initial value data 16 can be said to be the initial values of the phosphoric acid concentration, sulfuric acid concentration, and water concentration of the measurement target liquid. The initial value data 16 is given to the input/output circuit 10 before mixing silicon with the measurement target liquid. The initial value data 16 may be actual measured values obtained by near infrared spectroscopy, etc., or may be obtained by calculations such as simulation. The initial value data 16 can be used as a management value or a target value of the concentration of the measurement target liquid. As an example of the use of the measurement target liquid, an etching liquid used for etching treatment may be mentioned.

The variation value information 15 is not the concentration information of the measurement target liquid itself, but the information of the first reference liquid and the second reference liquid used to determine the silicon concentration of the measurement target liquid. The second reference liquid is a mixed liquid containing phosphoric acid, sulfuric acid as the second acid, and water without silicon. Specifically, the variation value information 15 shows the phosphoric acid, sulfuric acid, and the first concentration of water added to the second reference liquid with the first reference liquid of silicon so as to become the reference silicon concentration, and the second reference liquid without the added silicon The relationship between the second concentration of phosphoric acid, sulfuric acid, and water, and the reference silicon concentration. The variation value information 15 has a plurality of modes for the correspondence between the first concentration, the second concentration, and the reference silicon concentration. The first concentration and the second concentration are obtained by, for example, measurement with a near-infrared beam splitter. The change value information 15 is given by the near-infrared beam splitter before the measurement of the silicon concentration of the measurement target liquid. Table 1 shows an example of the concept of the second concentration. [Table 1]

The example in Table 1 shows an example of the second concentration obtained by the near-infrared spectrometer measurement of phosphoric acid, sulfuric acid, and water for the second reference liquid. As shown in Table 1, there are a plurality of concentrations (wt%) of phosphoric acid, sulfuric acid, and water measured at the second concentration, specifically, the near-infrared spectrometer of the second reference liquid (in Table 1 is 4 types) mode. The number of modes of the second concentration is not limited to four types, and can be adjusted according to the use of the measurement target liquid, and can be set to one type or two or more types.

The first concentration is the concentration (wt%) of phosphoric acid, sulfuric acid, and water measured by a near-infrared spectrometer by mixing silicon at the reference silicon concentration with the first reference liquid of the second reference liquid satisfying the second concentration. If silicon is added to the second reference liquid, the concentrations of phosphoric acid, sulfuric acid, and water change from the second concentration. The variation range is affected by the concentration of silicon added. Table 2 and FIGS. 2 to 5 show an example of the concept of the relationship between the first concentration and the reference silicon concentration. The first concentration (wt%) of phosphoric acid, sulfuric acid, and water obtained by the near-infrared spectrometer measurement when silicon was mixed with 50 ppm and 150 ppm in a plurality of second reference liquids with the second concentration 1 shown in Table 1 %) corresponds to the 1st concentration 1~2. The first concentration 3 to 5 is the phosphoric acid, sulfuric acid, and water obtained by the near-infrared spectrometer measurement when silicon is mixed with 50 ppm, 70 ppm, and 150 ppm in a plurality of second reference liquids with the second concentration 2. The first concentration (wt%). In addition, the first concentrations 6 to 8 are phosphoric acid, sulfuric acid, and sulfuric acid measured by a near-infrared spectrometer when silicon is mixed with 50 ppm, 70 ppm, and 150 ppm in a plurality of second reference liquids having a second concentration of 3, and The first concentration of water (wt%). In addition, the first concentrations 9 to 10 are the first phosphoric acid, sulfuric acid, and water measured by a near-infrared spectrometer when silicon is mixed with a plurality of second reference liquids having a second concentration at 50 ppm and 150 ppm. 1 Concentration (wt%). [Table 2]

Fig. 2 shows the relationship between the phosphoric acid concentration (wt%), sulfuric acid concentration (wt%) and Si concentration (ppm) in the first concentrations 1 to 2.

Fig. 3 shows the relationship between the phosphoric acid concentration (wt%), sulfuric acid concentration (wt%) and Si concentration (ppm) in the first concentrations 3 to 5.

FIG. 4 shows the relationship between the phosphoric acid concentration (wt%), sulfuric acid concentration (wt%) and Si concentration (ppm) in the first concentrations 6 to 8.

FIG. 5 shows the relationship between the phosphoric acid concentration (wt%) and sulfuric acid concentration (wt%) and Si concentration (ppm) in the first concentrations 9 to 10.

That is, as shown in FIGS. 2 to 5, if silicon is added to the second reference liquid, the ratio of phosphoric acid, sulfuric acid, and water changes. There are various modes of the degree of change. The change value information 15 can be said to display information of a plurality of modes for the manner of change of the ratio. Tables 1 and 2 and the examples in FIGS. 2 to 5 show the cases of 2 to 3 modes, but it can be either 1 mode or more than 4 modes of information. In addition, the variable value information 15 can be obtained by calculation by simulation or the like, instead of being obtained by measurement by near infrared light spectroscopy as described above.

Next, the details of the processor 11 will be described. The processor 11 performs the function of calculating the silicon concentration of the measurement target liquid mixed with the silicon by executing the silicon concentration measurement program. 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 as an initial value data acquisition unit 20, a measured value data acquisition unit 21, a first comparison unit 22, a first selection unit 23, a first concentration The group determination unit 24, the second comparison unit 25, the second selection unit 26, and the silicon concentration determination unit 27 function.

The initial value data acquisition unit 20 acquires the initial value data 16 via the input/output circuit 10. The measured value data obtaining unit 21 obtains the measured value data 17 from the near infrared beam splitter. The first comparison unit 22 compares the second concentration described with Table 1 as an example and the obtained initial value data 16. The first selection unit 23 selects any of the second concentrations illustrated in Table 1 based on the comparison result of the first comparison unit 22. The first concentration group determination unit 24 determines the first concentration group corresponding to the selected second concentration among the plurality of first concentrations described in Table 2 as an example. The second comparison unit 25 compares the determined first concentration group with the acquired measured value data 17. The second selection unit 26 selects any first concentration from the first concentration group based on the comparison result of the second comparison unit 25. The silicon concentration determination unit 27 determines the silicon concentration in the measurement target liquid based on the first concentration selected by the second selection unit 26. Then, the display 14 displays the determined silicon concentration.

2. Operation of measuring device Next, the operation of the measuring device of the embodiment will be described. First, the flow of the entire operation will be described with reference to FIG. 7. 7 is a flowchart showing the overall flow of the operation of the measuring device. FIG. 7 illustrates an example in which the measurement target liquid is an aqueous solution containing phosphoric acid and sulfuric acid. First, the initial value data acquisition unit 20 of the processor 11 receives the second concentration including the phosphoric acid concentration, sulfuric acid concentration, and water concentration of the measurement target liquid in the state before silicon mixing in the input/output circuit 10 as the initial value data 16 The RAM 13 is kept (step S1). The variable value information 15 may be retained in the RAM 13 before step S1 or may be stored in the RAM 13 after step S1. Thereafter, after mixing silicon with the measurement target liquid, the phosphoric acid concentration, sulfuric acid concentration, and water concentration of the measurement target liquid are measured using a near-infrared spectrometer to obtain an absorption spectrum. Then, if, for example, the input/output circuit 10 of the measuring device 1 receives the measurement command of the silicon concentration in the liquid to be measured (step S2), the measured value data acquisition unit 21 of the processor 11 receives in the input/output circuit 10 The first concentration of phosphoric acid concentration, sulfuric acid concentration, and water concentration of the liquid to be measured after that is held in the RAM 13 as the measured value data 17 (step S3). Next, the first comparison unit 22 of the processor 11 compares the initial value data 16 obtained in step S1 with the second density of the variable value information 15 held in the RAM 13. Specifically, the first comparison unit 22 compares the phosphoric acid, sulfuric acid, and sulfuric acid of the measurement target liquid in the state before silicon mixing as the initial concentration data 16 with the second concentrations 1 to 4 illustrated in Table 1 as the second concentration. The concentration of water. Then, the first selection unit 23 selects the second concentration that is closest (or the same) among the comparison results of the first comparison unit 22 (step S4). It is assumed that the first selection unit 23 selects, for example, the second density 1. Next, the first density group determination unit 24 determines the first density group corresponding to the selected second density 1 among the variable value information 15 held in the RAM 13 (step S5). In the case of Table 2, the first concentration group corresponding to the second concentration 1 corresponds to the first concentration 1 and the first concentration 2.

The second comparison unit 25 compares the measured value data 17 obtained in step S3 with the first concentration 1 and the first concentration 2 obtained in step S5. Then, the second selection unit 26 selects the closest (or the same) first concentration among the comparison results of the second comparison unit 25 (step S6). It is assumed that the first density selected in step S6 among the first density 1 and the first density 2 is the first density 1. As shown in Table 2, the first concentration 1 corresponds to the phosphoric acid concentration, sulfuric acid concentration, and water concentration of the first reference liquid obtained by adding silicon to the second reference liquid satisfying the second concentration 1 so that the concentration becomes 50 ppm. The measured value data 17 of the measurement target liquid is the same as or closest to the first concentration 1. Therefore, the silicon concentration determination unit 27 determines that the silicon concentration of the measurement target liquid is 50 ppm (step S7).

In addition, the second comparison unit 25 and the second selection unit 26 can obtain the silicon concentration by, for example, linear approximation. That is, the silicon concentration shown in Table 2 has discrete values. However, it can also be obtained by linear approximation using the discrete values as shown in the dashed and solid lines in the graphs of FIGS. 2 to 5.

For example, assume that the initial value data 16 acquired in step S1 is the second concentration 2, and the measured value data 17 acquired in step S3 is the following data. • Phosphoric acid concentration: 85.41 wt% • Sulfuric acid concentration: 1.53 wt% • Water concentration: 13.06 wt%

If so, these values are approximately consistent with the linearity shown in Figure 3. In addition, the value of each concentration is approximately halfway between the value when the silicon concentration is 70 [ppm] and the value when the silicon concentration is 150 [ppm]. Therefore, the silicon concentration in this case can be expected to be around 110 [ppm]. These calculations can be performed by any of the second comparison unit 25, the second selection unit 26, and the silicon concentration determination unit 27.

Through the above steps, the measurement of the silicon concentration of the measurement target liquid containing phosphoric acid, sulfuric acid as the second acid, and water is performed. Therefore, according to the measuring instrument of the embodiment, the silicon concentration in the liquid to be measured can be obtained based on the concentration change of phosphoric acid and the second acid before and after the mixing of the silicon for the liquid to be measured containing phosphoric acid, the second acid, and water. Therefore, the measuring instrument of the embodiment can measure the extremely small amount of silicon concentration of unavoidable impurities. This extremely small amount of silicon concentration cannot be measured by any one of specific gravity measurement methods such as near infrared spectroscopy, molybdenum yellow absorbance photometry, and conductivity measurement methods. This is due to the fact that in the case of the specific gravity measurement method, the concentration of silicon mixed into the liquid to be measured is too low to detect the change in specific gravity. In addition, in the case of molybdenum yellow absorption photometry, since the absorption derived from silicon and the absorption derived from phosphoric acid are repeated and inseparable, the concentration of silicon cannot be measured.

Furthermore, according to the measuring instrument of the embodiment, since the time required for the measurement can be shortened, it is possible to grasp the silicon concentration that changes in real time due to the etching process or the like.

In addition, the measuring instrument of the embodiment may further include a near-infrared beam splitter. The near-infrared beam splitter can measure the concentration of phosphoric acid, sulfuric acid, and water in the liquid to be measured with high accuracy and easily, so the silicon concentration in the liquid to be measured can be obtained with high precision.

It is also feasible that the processor 11 calculates the silicon mixture based on the concentration of phosphoric acid, sulfuric acid, and water of the measurement target liquid before silicon mixing, and the concentration of phosphoric acid, sulfuric acid, and water of the measurement target liquid after silicon mixing The silicon concentration of the liquid to be measured later is used as the reference silicon concentration instead of using the measured value as the reference silicon concentration.

[Second Embodiment] An etching system will be described. The etching system is a system for etching silicon compounds using an etching solution containing phosphoric acid and water. The silicon compound may be, for example, a film of silicon compound formed on the substrate. Examples of substrates include SiC substrates, GaN substrates, and the like. The etching system of the embodiment will be described with reference to FIG. 8. 1. Composition of etching system

The etching system shown in FIG. 8 includes: a first container (etching processing section) 31 for etching a silicon compound using an etching solution containing phosphoric acid and water; and a second container (phosphoric acid supply section) 32 for introducing phosphoric acid The first container 31; the third container (water supply unit) 33 for introducing water into the first container 31; the near-infrared beam splitter 34; and the measuring unit 35 for measuring the content of the sample liquid (measurement target liquid) Silicon concentration; and control section 36. The near-infrared beam splitter 34 includes a fourth container (not shown in FIG. 8) for acquiring an etching solution from the first container 31 and containing a sample solution obtained by adding sulfuric acid to the etching solution. An example of the fourth container is shown in Fig. 9. The measuring device of the first embodiment is used as the measuring unit 35. The control unit 36 controls the entire etching system. In addition, the control unit 36 introduces the phosphoric acid in the second container 32 into the first container 31 and/or introduces the water in the third container 33 into the first container 31 according to the measurement result of the measuring unit 35. In FIG. 8, for convenience of illustration, the control unit 36 seems to be electrically connected only to the first container 31 and the second container 32, but is electrically connected to each unit constituting the etching system, and may be connected between the control unit 36 and each unit Perform signal exchange.

A buffer tank 37 and a supplementary tank 38 are arranged in the path from the second container 32 and the third container 33 to the first container 31. Each of the second container 32 and the third container 33 is connected to the buffer tank 37 via the first piping 39 and the second piping 40. The buffer tank 37 is connected to the supplementary tank 38 via the third pipe 41. The flow meter 42 and the valve 43 are provided in order from the upstream side of the third pipe 41. The concentration meter 44 is connected to the supplementary tank 38 via the fourth pipe 45.

An etching solution 46 containing phosphoric acid and water is contained in the first container 31. The silicon compound 47 is immersed in the etching solution 46, and the silicon compound 47 is etched. During the etching process, the etching solution 46 overflowing from the first container 31 is temporarily stored in the storage tank 48. The storage tank 48 is connected to the supplementary tank 38 via the fifth piping 49. The fifth piping 49 is provided with a filter (not shown). The filter removes foreign substances contained in the etching liquid. After the etching solution 46 overflowing from the first container 31 during the etching process is recovered to the storage tank 48, the etching liquid 46 from the storage tank 48 is accommodated in the replenishing tank 38 through the fifth pipe 49 through the filter. In addition, the storage tank 48 is also connected to the drain pipe 50. The replenishment tank 38 is connected to the first container 31 via the sixth pipe 51. The pump 52 and the heater 53 are provided in this order on the upstream side of the sixth pipe 51. Here, the system including the path from the replenishing tank 38 to the first container (etching processing section) 31 and the path from the first container 31 to the replenishing tank 38 via the storage tank 48 is referred to as an etching processing system. In the etching processing system, in addition to the first container 31, the replenishing tank 38, and the storage tank 48, the piping in the above path and the like are also included.

The etching treatment system is filled with an etching solution 46 containing phosphoric acid and water. In the etching process, due to evaporation of water, the capacity of the etching solution 46 decreases, and the concentration of phosphoric acid becomes high, or the concentration of phosphoric acid becomes low due to the consumption of phosphoric acid. Therefore, the concentration of phosphoric acid in the etching solution 46 must be managed. The phosphoric acid concentration of the etching solution 46 of the etching processing system is measured by the densitometer 44 and sends a signal to the control unit 36 when it deviates from the management value. When receiving this signal, the control unit 36 adjusts the supply amount of phosphoric acid from the second container 32 to the buffer tank 37 and the supply amount of water from the third container 33 to the buffer tank 37, and prepares phosphoric acid water of a specific concentration as a supplementary liquid. When the valve 43 is opened, the supply amount is adjusted by the flow meter 42 and the supplementary liquid in the buffer tank 37 is supplied to the etching processing system. By controlling the phosphoric acid concentration of the replenishing liquid and the supply amount of the replenishing liquid from the buffer tank 37 to the etching processing system, the phosphoric acid concentration of the etching liquid 46 of the etching processing system can be set within the management value. Examples of increasing the phosphoric acid concentration of the etching solution 46 include increasing the phosphoric acid concentration of the replenishing solution and reducing the supply amount of the replenishing solution from the buffer tank 37 to the etching processing system. On the other hand, examples of reducing the phosphoric acid concentration of the etching solution 46 include reducing the phosphoric acid concentration of the replenishing solution and increasing the supply amount of the replenishing solution from the buffer tank 37 to the etching processing system. In addition, the adjustment of the supply amount of the supplemental liquid from the buffer tank 37 to the etching processing system can also be performed by monitoring the supply amount with the flow meter 42 and adjusting the opening amount of the valve 43.

In addition, when the management values of the phosphoric acid concentration and the water concentration are changed by changing the etching conditions such as the phosphoric acid concentration, water concentration, or temperature of the etching solution 46, a signal is sent to the control section 36, and the control section 36 resets the etching solution 46 Set new management value for the management value of phosphoric acid concentration and water concentration.

The etching system may include a water supply tank for supplying evaporated water to the first container 31 in addition to the third container 33.

In addition, the etching system may replace the concentration meter 44 or include a concentration meter for directly measuring the phosphoric acid concentration of the etching solution 46 in the first container 31 in addition to 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 spectroscope 34 includes a test container 60 as a fourth container, a light source 61, a spectroscope 62, an arithmetic unit 63, and a temperature regulator 64.

The test container 60 is a container that is transparent to near infrared light, for example. Further, to the test container 60, the etching solution 46 is supplied from the first container 31 for etching the silicon compound, and sulfuric acid is supplied from a sulfuric acid supply unit different from the first container 31. As a result, a sample liquid obtained by adding sulfuric acid to the etching solution 46 in which silicon is dissolved is purified in the test container 60 as the measurement target liquid. The supply rate and supply timing of the etching solution 46 and sulfuric acid are controlled by, for example, the control unit 36. The temperature of the sample liquid (measurement target liquid) in the test container 60 is controlled by the temperature regulator 64. In order to improve the measurement accuracy of the near-infrared spectroscopy measurement, it is desirable that the temperature of the sample liquid is controlled to be below room temperature.

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

The spectroscope 62 splits the near-infrared light passing through the test container 60 to obtain the absorption spectrum of the sample liquid (measurement target liquid).

The arithmetic unit 63 calculates the phosphoric acid concentration, sulfuric acid concentration, and water concentration of the sample liquid (measurement target liquid) based on the absorption spectrum obtained by the spectroscope 62, and outputs the result to the measurement unit 35. That is, the initial value data 16 and the measured value data 17 described in FIG. 1 of the first embodiment are supplied from the arithmetic unit 63 to the measurement unit 35. Furthermore, the second concentration and the first concentration can also be generated by information from the arithmetic unit 63.

2. Operation of the etching system The operation of the etching system will be described with reference to FIGS. 10 and 11. FIG. 10 is a flowchart showing the flow of the silicon concentration management of the etching system. On the other hand, FIG. 11 is a flowchart showing the phosphoric acid concentration management of the etching system.

Regarding phosphoric acid concentration management The initial values of the phosphoric acid concentration, sulfuric acid concentration, and water concentration of the etching solution 46 of the etching processing system are input to the measuring unit 35. The initial value of the phosphoric acid concentration and the water concentration are suitable for specific etching treatment conditions, and are measured by, for example, the concentration meter 44. The etching solution 46 used for the etching treatment of 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 liquid for the measurement of the near-infrared beam splitter 34 in order to improve the accuracy of silicon concentration measurement. The sulfuric acid concentration suitable for the determination of silicon concentration may vary due to the concentration of phosphoric acid and water. Therefore, in addition to the phosphoric acid concentration and the water concentration, the initial value of the etching solution 46 includes the sulfuric acid concentration corresponding to these concentrations. The entered initial value is held in the RAM 13 as the initial value data 16. The measurement unit 35 calculates the ratio of phosphoric acid to water based on the initial value of the phosphoric acid concentration and the water concentration, and sends the calculated ratio to the control unit 36 as a management value (step S20).

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

When the ratio of phosphoric acid to water in the etching solution 46 of the etching processing system deviates from the management value (No in step S23), a signal is sent to the control unit 36. When receiving this signal, the control unit 36 adjusts the supply amount of phosphoric acid from the second container 32 to the buffer tank 37 and the supply amount of water from the third container 33 to the buffer tank 37, and prepares phosphoric acid water of a specific concentration as a supplementary liquid (step S24). The valve 43 is opened, and the supply amount is adjusted by the flow meter 42 while supplying the supplementary liquid in the buffer tank 37 to the etching processing system (step S25). The production (preparation) and supply of the supplementary liquid are performed until the ratio of phosphoric acid to water of the etching liquid 46 of the etching processing system falls within the management value.

Regarding silicon concentration measurement A silicon concentration measurement command is sent to the control unit 36 at a certain time from the start of the etching process. The control unit 36 collects a part of the etching liquid 46 in the etching processing system into the test container 60 to obtain a sample liquid (step S11). As described above, the etching solution 46 does not contain sulfuric acid (No in step S12). Therefore, the control unit 36 adds sulfuric acid to the sample liquid so as to have a specific concentration to obtain a measurement target liquid (step S13). Then, the near-infrared spectroscope 34 measures the phosphoric acid concentration, sulfuric acid concentration, and water concentration of the measurement target liquid in the test container 60 (step S14). If the obtained measurement result is input to the measurement part 35, it will hold the RAM 13 as the measured value data 17.

The control unit 36 sends a signal to the measurement unit 35, and the first comparison unit 22 of the measurement unit 35 compares the second density of the variation value information 15 of the RAM 13 with the initial value data 16. The first comparison unit 22 selects any second concentration from the plurality of second concentrations based on the comparison result. The first concentration group determination unit 24 of the measurement unit 35 determines the first concentration group corresponding to the selected second concentration among the plurality of change value information 15 of the first concentration. The second comparison unit 25 of the measurement unit 35 compares the determined first concentration group with the acquired measurement value data 17. The second selection unit 26 of the measurement unit 35 selects any first concentration from the first concentration group based on the comparison result of the second comparison unit 25. The silicon concentration determination unit 27 of the measurement unit 35 determines the reference silicon concentration corresponding to the first concentration selected by the second selection unit 26 as the silicon concentration in the liquid to be measured. Then, the measurement unit 35 causes the display 14 to display the determined silicon concentration (step S15). In addition, the details of the processing of step S15 are as explained using FIG. 7 in the first embodiment.

When the silicon concentration calculated in step S15 deviates from the management value (NO in step S16), the control unit 36 sends a signal to discharge the etching solution 46 in the storage tank 48 to the outside of the system through the drain pipe 50 (step S17). Furthermore, the control unit 36 sends a signal to adjust the supply amount of phosphoric acid from the second container 32 to the buffer tank 37 and the supply amount of water from the third container 33 to the buffer tank 37 to prepare phosphoric acid water of a specific concentration as a supplementary liquid (step S18).

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

After that, a silicon concentration measurement command is sent 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 trace amounts in the etching liquid can be measured, it is possible to instantly grasp the concentration of silicon that changes due to the etching process.

The etching system is not limited to a system using an etching solution that does not contain sulfuric acid, but may be a system that contains sulfuric acid in the etching solution. An example of this is shown in Fig. 12. The etching system shown in FIG. 12 includes, in addition to the fifth container 70 for introducing sulfuric acid into the first container 31, and the seventh piping 71 connecting the fifth container 70 and the buffer tank 37, it also has etching as shown in FIG. The system has the same composition. In the silicon concentration management of 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 of the near-infrared beam splitter 34 can be omitted (step S13), but When the concentration of sulfuric acid in the sample liquid is low, in order to set the concentration of sulfuric acid in the sample liquid to a concentration suitable for measurement, a step of adding sulfuric acid to the sample liquid may be performed (step S13). In addition, when the concentration of sulfuric acid in the sample liquid is high, a step of adding phosphoric acid and/or water to the sample liquid to reduce the concentration of sulfuric acid is performed.

In addition, in the above-mentioned embodiment, the case where the software installs the function of calculating the silicon concentration has been described as an example. However, it can be installed either by hardware or by a combination of software and hardware. When installed by software, its function can be stored as one or more commands or codes on a computer-readable memory medium or transmitted by the memory medium. The 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 RAM, ROM, EEPROM (registered trademark) (including a USB memory or a memory card), a CD-ROM, a magnetic disk such as a hard disk, and the like can be used.

In addition, in the above embodiment, the case where the second concentration (Table 1) and the first concentration (Table 2) are regarded as separate information has been described as an example, but they may be integrated data. That is, as described above, Tables 1 and 2 are used to select any of the first concentrations contained in the table and obtain the silicon concentration based on the reference silicon concentration corresponding to the selected first concentration. Therefore, Tables 1 and 2 need not be individual structures, and their forms are not limited to those described in Tables 1 and 2, as long as the first concentration can be selected based on the measured value data 17. For example, it may be the case of maintaining the amount of change in the ratio of phosphoric acid, sulfuric acid, and water when silicon is not included, the concentration of silicon, and the ratio of phosphoric acid, sulfuric acid, and water when silicon is dissolved.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their changes are included in the scope and gist of the invention, and are included in the invention described in the patent application scope and its equivalent scope.

1‧‧‧Detector 10‧‧‧I/O circuit 11‧‧‧ processor 12‧‧‧ROM 13‧‧‧RAM 14‧‧‧Monitor 15‧‧‧ Changed value information 16‧‧‧Initial value data/initial value information 17‧‧‧Measured value data/measured value information 18‧‧‧ Silicon concentration measurement program 20‧‧‧Initial value data acquisition department 21‧‧‧Measured value data acquisition department 22‧‧‧First Comparison Department 23‧‧‧ First Selection Department 24‧‧‧The first concentration group decision department 25‧‧‧Comparative Department 2 26‧‧‧ 2nd Selection Department 27‧‧‧Silicon concentration determination department 31‧‧‧The first container/etching processing department 32‧‧‧Second container/phosphoric acid supply unit 33‧‧‧The third container/water supply unit 34‧‧‧Near infrared beam splitter 35‧‧‧Measurement Department 36‧‧‧Control Department 37‧‧‧Buffer tank 38‧‧‧Supplement slot 39‧‧‧First piping 40‧‧‧ 2nd piping 41‧‧‧ Third piping 42‧‧‧Flowmeter 43‧‧‧Valve 44‧‧‧Concentration meter 45‧‧‧ 4th piping 46‧‧‧Etching solution 47‧‧‧Silicon compound 48‧‧‧Storage tank 49‧‧‧Fifth piping 50‧‧‧Drain 51‧‧‧ 6th piping 52‧‧‧Pump 53‧‧‧ Heater 60‧‧‧Test container 61‧‧‧Light source 62‧‧‧Splitter 63‧‧‧Calculator 64‧‧‧Temperature regulator 70‧‧‧The fifth container 71‧‧‧ 7th piping

Fig. 1 is a block diagram of a measuring device according to an embodiment. FIG. 2 is a graph showing the relationship between the phosphoric acid concentration, sulfuric acid concentration, and silicon concentration for the first concentration of 1-2. FIG. 3 is a graph showing the relationship between the phosphoric acid concentration, sulfuric acid concentration, and silicon concentration for the first concentration of 3 to 5. 4 is a graph showing the relationship between the phosphoric acid concentration, sulfuric acid concentration, and silicon concentration for the first concentration of 6-8. FIG. 5 is a graph showing the relationship between the phosphoric acid concentration, sulfuric acid concentration, and silicon concentration for the first concentration of 9-10. 6 is a functional block diagram of a processor included in the measuring device of FIG. Fig. 7 is a flowchart showing the operation flow of the measuring device of the embodiment. FIG. 8 is a block diagram showing an example of an etching system of an embodiment. 9 is a conceptual diagram of the near-infrared beam splitter of the etching system of FIG. 8. FIG. 10 is a flowchart showing the flow of silicon concentration management of the etching system of FIG. 8. 11 is a flowchart showing the flow of phosphoric acid concentration management of the etching system of FIG. 8. 12 is a block diagram showing another example of the etching system of the embodiment.

1‧‧‧Detector

10‧‧‧I/O circuit

11‧‧‧ processor

12‧‧‧ROM

13‧‧‧RAM

14‧‧‧Monitor

15‧‧‧ Changed value information

16‧‧‧Initial value data/initial value information

17‧‧‧Measured value data/measured value information

18‧‧‧ Silicon concentration measurement program

Claims (10)

A measuring instrument comprising: an input/output unit which is inputted to display phosphoric acid containing a phosphoric acid, a second acid having a dissociation constant pK _{a1 which} is smaller than the phosphoric acid and a second acid having a dissociation constant pK which is a smaller acid dissociation constant pK, and water; The measured value information of the concentration of the second acid and water; the memory, which holds the variable value information, which includes the reference liquid containing the phosphoric acid, the second acid, and the water so as to become the reference silicon concentration The relationship between the concentration change of the phosphoric acid, the second acid, and the water during silicon and the reference silicon concentration; and a processor based on the measured value information input to the input/output unit and read from the memory The aforementioned change value information obtains the silicon concentration of the measurement target liquid equivalent to the measurement value information. The measuring device according to claim 1, wherein the measurement value information is obtained from an absorption spectrum obtained by near-infrared spectroscopy of the measurement object liquid. The measuring device according to claim 1 or 2, wherein the aforementioned measurement object liquid is an etching liquid for etching a silicon compound. The measuring device according to any one of claims 1 to 3, wherein the input/output unit inputs: the measured value information; and the phosphoric acid, the second acid, and the water in a state where the measurement target liquid does not contain silicon The initial value information of the concentration; and the variable value information includes, as the relationship, a plurality of the first concentrations of the phosphoric acid, the second acid, and the water when the silicon is added to the reference liquid so as to become the reference silicon concentration 2. The relationship between the phosphoric acid, the second acid and the second concentration of the water before the addition of the reference liquid, and the reference silicon concentration; the processor compares the concentration of the initial value information with the plurality of the second concentration Select any one of the plurality of the aforementioned second concentrations, select the aforementioned first concentration corresponding to the selected aforementioned second concentration, compare the selected concentration of the aforementioned first concentration with the measured value information, based on the comparison As a result, the reference silicon concentration corresponding to the selected first concentration is determined as the silicon concentration of the measurement target liquid. The measuring device according to any one of claims 1 to 4, wherein the second acid is sulfuric acid. An etching system comprising: a first container for etching a silicon compound using an etching solution containing phosphoric acid and water; a second container for introducing phosphoric acid into the first container; a third container for introducing water Introducing the first container; the fourth container for acquiring the etching solution from the first container and containing a measurement target liquid obtained by adding sulfuric acid to the etching solution; and a measurement unit provided with any one of claims 1 to 5. A measuring instrument for measuring the concentration of silicon contained in the measurement target liquid in the fourth container; and a control unit corresponding to the measurement result of the measurement unit, introducing the phosphoric acid from the second container into the second container 1 container, and/or introducing the water from the third container into the first container. A method for measuring silicon concentration, comprising: receiving from a near-infrared light spectrometer a measurement object liquid containing phosphoric acid, a second acid having a dissociation constant pK _{a1 which} is smaller than the phosphoric acid, and a second acid having an acid dissociation constant pK, and water The measured value information of the concentration of the phosphoric acid, the second acid and the water; read out the variable value information from the memory, the variable value information includes the reference liquid containing the phosphoric acid, the second acid and the water to become the reference silicon The relationship between the concentration change of the phosphoric acid, the second acid and the water when the silicon is added and the reference silicon concentration; and obtaining the measurement target equivalent to the received measurement value information based on the read variation value information The concentration of silicon contained in the liquid. According to the method for measuring the silicon concentration of claim 7, it is further provided to receive the initial value information indicating the concentration of the phosphoric acid, the second acid, and the water in a state where the measurement target liquid does not contain silicon; The relationship includes a plurality of first concentrations of the phosphoric acid, the second acid, and the first concentration of the water when the silicon is added to the reference liquid so as to become the reference silicon concentration, the phosphoric acid before the silicon, the preceding The relationship between the second concentration of the second acid and the water, and the reference silicon concentration; compare the concentration of the initial value information with the plurality of second concentrations and select any one of the plurality of second concentrations, select and The first concentration corresponding to the selected second concentration is compared with the concentration of the selected first concentration and the measured value information, and the reference silicon concentration corresponding to the selected first concentration is determined based on the result of the comparison It is the silicon concentration of the aforementioned measurement target liquid. A silicon concentration measurement program for measuring the silicon concentration of the measurement liquid containing phosphoric acid, the second acid having a smaller acid dissociation constant pK _a1 than the phosphoric acid first dissociation constant pK _a1 , and water, by Executed by the processor to cause the processor to receive the phosphoric acid and the second acid showing the measurement target liquid containing phosphoric acid, a first acid dissociation constant pK _a1 having a smaller acid dissociation constant pK _a1 than the phosphoric acid, and water to be measured , And the measured value information of the concentration of water; read out the variable value information from the memory, the variable value information includes when adding silicon to the reference liquid containing the phosphoric acid, the second acid and the water in such a way as to become the reference silicon concentration The relationship between the concentration change of the phosphoric acid, the second acid and the water and the reference silicon concentration; based on the change value information read out, the concentration of silicon contained in the measurement target liquid corresponding to the received measurement value information is calculated . A silicon concentration measurement program according to claim 9, which causes the processor to receive the measured value information and display the initial values of the concentrations of the phosphoric acid, the second acid, and the water in a state where the measurement target liquid does not contain silicon Information; the variable value information includes, as the relationship, a plurality of kinds of the phosphoric acid, the second acid and the first concentration of the water when the silicon is added to the reference liquid so as to become the reference silicon concentration, the addition of the reference liquid The relationship between the phosphoric acid before the silicon, the second concentration of the second acid and the second concentration of the water, and the reference silicon concentration; and the processor compares the concentration of the initial value information with the plurality of the second concentrations and selects the plurality Any one of the aforementioned second concentrations, select the aforementioned first concentration corresponding to the selected aforementioned second concentration, compare the selected concentration of the aforementioned first concentration with the measured value information, and based on the result of the aforementioned comparison, The reference silicon concentration corresponding to the first concentration is determined as the silicon concentration of the measurement target liquid.

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