JPH07270370A - Liquid control means - Google Patents

Abstract

PURPOSE:To confirm the normal operation of a detection means by judging whether the concn. change in a soln. detected by a detection means is generated in a sensor diagnosing mode I when the concn. of the effective component in the soln. is altered, and judging abnormality by the detection means in a sensor diagnosing mode II when it is judged that there is no change in the detected concn. even when the concn. is altered. CONSTITUTION:In a sensor diagnosing mode I, the flow rates of a suction device 1 and a dilution device 3 are changed to change the concn. of hydrogen peroxide in a washing soln. and it is tested whether the detection signal of an oxygen sensor 23 is changed following those changes. In a sensor diagnosing mode II, the flow rate of the extraction gas supplied from an extraction gas supply device 5 is changed to change the concn. of oxygen in the extraction gas and it is tested whether the detection signal of the oxygen sensor 23 is changed following the concn. change. When there is no change, an alarm signal smoking abnormality is outputted by an alarm output circuit 12. By this constitution, it can be diagnosed whether the sensor functions accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid control device for measuring the concentration of components in a cleaning liquid, and more particularly to a liquid capable of reliably controlling the concentration of effective components that generate oxygen such as hydrogen peroxide and ozone in the cleaning liquid. Regarding management device.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Application No. 3-186623 and Japanese Patent Application No. 4-367 have been used as concentration analyzers for cleaning liquids such as semiconductors.
A liquid management device shown in No. 55 is known. Japanese Patent Application 3
No. 186623 discloses a liquid management device in which a fixed amount of a cleaning liquid is sampled and a reagent is appropriately applied to the cleaning liquid, and the concentration of the active ingredient in the cleaning liquid is determined based on the change in the oxidation-reduction potential associated with the appropriateness of the reagent. It is to be measured, and also Japanese Patent Application No. 4
-36755, the liquid management device decomposes the active ingredient in the cleaning liquid to generate oxygen gas, and measures the concentration of the effective component in the cleaning liquid based on the concentration of the generated oxygen gas. It is a thing.

In the liquid management device as described above, the detection values of the redox electrode (detecting means) for measuring the redox potential and the oxygen sensor (detecting means) for measuring the concentration of oxygen gas are predetermined. It is determined whether or not it is between the upper limit density threshold and the lower limit density threshold, and an alarm is output based on the determination result. Specifically, when the concentration of the active ingredient in the cleaning liquid is lower than the lower limit concentration threshold value, the wafer is not sufficiently cleaned, so that even if the next step is performed, impurities or dust on the wafer When the semiconductor wafer is damaged by the corrosion caused by these impurities and dust, on the other hand, the effective component concentration in the cleaning liquid exceeds the upper limit concentration threshold. May cause damage to part of the wafer due to excessive etching,
For this reason, when the detection values of the redox electrode for measuring the redox potential and the oxygen sensor for measuring the concentration of oxygen gas are not between the predetermined upper and lower concentration thresholds. An alarm is output to the operator to stop the semiconductor cleaning process or check the components of the cleaning liquid.

Although the upper limit concentration threshold value and the lower limit concentration threshold value are set as the above threshold values, the upper limit concentration threshold value is used to control the concentration of the effective component of the cleaning liquid. It is used only when the concentration of the active ingredient does not stabilize immediately after (the operator may confirm that the concentration is stabilized manually), and after this unstable time passes, the active ingredient It is consumed for wafer cleaning and the concentration thereof is reduced. Therefore, in the above-mentioned liquid management apparatus, it is only necessary to control whether or not the concentration of the effective component is reduced in the normal wafer cleaning operation. . That is, the upper limit concentration threshold value is not essential for controlling the concentration of the effective component of the cleaning liquid. Further, the above-mentioned lower limit concentration threshold value is stored in the "lower limit value storage means", and the "first determination means" determines whether or not the detection value of the oxygen sensor (detection means) is larger than the lower limit concentration threshold value.
The alarm based on the result of this determination is output by the "notifying means".

[0005]

By the way, in the liquid management apparatus constructed as described above, the detection means fails, and the detection value of the detection means becomes constant regardless of the actual effective component concentration in the cleaning liquid. If so, it becomes impossible to determine whether or not the actual concentration of the active ingredient in the cleaning liquid is correct, and thus it becomes impossible to determine when the cleaning liquid should be replaced. Further, when the detection value of the detection means becomes constant at a level lower than the lower limit concentration threshold, the alarm may not be output even though the actual concentration of the cleaning liquid is lower than the lower limit value. As a result, it is not possible to accurately know when to replace the cleaning liquid, and it is impossible to completely clean the wafer. The output abnormality in which the above-mentioned detection means becomes constant regardless of the actual concentration of the effective component in the cleaning liquid is also caused by dirt on the sensor, disconnection of the cable, leakage from the pipe supplying the cleaning liquid, or the like. .

The present invention has been made in view of the above circumstances, and changes the effective component in the solution to be measured by the detection means, and whether or not the detection value of the detection means changes accordingly. It is an object of the present invention to provide a liquid management device capable of determining whether or not the detection means is normal by detecting whether or not the detection means is normal.

[0007]

In order to achieve the above object, the present invention provides a detecting means for detecting the concentration of an active ingredient in a solution, and a lower limit value for storing the lower limit value of the active ingredient in the solution. Storage means, first determination means for determining whether or not the concentration of the active ingredient in the solution detected by the detection means is lower than the lower limit value stored in the lower limit value storage means, and the first determination means in the solution When the first determination means determines that the concentration of the active ingredient has become lower than the lower limit value stored in the lower limit value storage means, in the liquid management device comprising notification means for notifying this, in the solution Concentration changing means for changing the concentration of the active ingredient and determining whether the concentration detected by the detecting means changes when the concentration of the active ingredient in the solution is changed by the concentration changing means Second judge If the second judging means judges that the concentration detected by the detecting means does not change even if the concentration of the active ingredient in the solution is changed by the concentration changing means, an abnormality of the detecting means is detected. And an abnormality detecting means for performing the above.

[0008]

According to the present invention, when the concentration of the active ingredient in the solution is changed by the concentration changing means, the second judging means
It is determined whether or not the concentration in the solution detected by the detection means changes. Further, even if the concentration of the active ingredient in the solution is changed by the concentration changing means by the second judging means,
When it is determined that the detected concentration of the detecting means does not change, the abnormality detecting means determines that the detecting means has an abnormality. That is, in the present invention, it is possible to know whether or not the detection means is functioning normally, based on the abnormality determination result of the abnormality detection means.

[0009]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 shows a block diagram of a liquid management apparatus, which is divided into a fluid flow channel system 100 including a fluid flow channel and a control system 101 for processing data and control signals. The fluid flow path system 100 includes a suction device 1, a heating / decomposing device 2, a diluting device 3, an extracting device 4, an extracting gas supply device 5, a dehumidifier 6, and an oxygen detecting means 7. Each component is connected by a flow path. The control system 101 includes an amplitude detection circuit 9, an averaging circuit 10, a control arithmetic circuit 11, an alarm output circuit 12, an alarm setting circuit 13,
The printer 14 includes a printer 14, a display unit 15, and an operation unit 16, and these components are connected by a cable.

First, each component of the fluid channel system 100 will be described. The suction device 1 and the diluting device 3 are connected to the heating / decomposing device 2, and the heating / decomposing device 2 and the extraction gas supply device 5 are the extracting device. 4, the extraction device 4 is a dehumidifier 6
It is connected to the oxygen detection means 7 via. Suction device 1
Is a transportation means such as a pump,
The cleaning liquid is sucked through the channel A from a tank or a cleaning tank (not shown) in which the cleaning liquid such as a semiconductor is stored. The cleaning liquid contains components such as hydrogen peroxide and ozone that generate oxygen. As the cleaning liquid, in particular (component in the present embodiment for generating oxygen hydrogen peroxide) for semiconductor cleaning solution consisting of _{HCl-H 2 O 2 -H 2} O are used.

The diluting device 3 is composed of a transportation means such as a pump, and is supplied with pure water (diluting liquid) through the flow path B.
Is supplied to and added to the cleaning liquid sucked by the suction device 1. The heating / decomposing device 2 is filled with a container 20 for temporarily storing the cleaning liquid, a hot tube (not shown) for heating the cleaning liquid in the container 20, and the container 20.
A solid catalyst 21 that decomposes components such as hydrogen peroxide and ozone to generate oxygen gas. Then, in the heating / decomposing device 2, the components such as hydrogen peroxide in the cleaning liquid are decomposed by the solid catalyst 21 while the cleaning liquid is heated by the hot tube, and oxygen is generated. Then, the oxygen generated in the thermal decomposition apparatus 2 is extracted further from the extraction apparatus 4 located further downstream together with the cleaning liquid.
Is supplied to. Although the heating / decomposing device 2 decomposes hydrogen peroxide using a catalyst to generate oxygen, the present invention is not limited to this, and oxygen may be generated by electrolysis. Also, the heating / decomposition device 2 is
The heating means constituted by the hot tube and the decomposition means constituted by the catalyst are integrated in the same container 20, but the invention is not limited to this, and the separate containers may be used.
A heating means may be provided on the upstream side and a decomposition means may be provided on the downstream side.

The extraction device 4 has a reaction cell 22 for extracting the oxygen gas obtained by the heating / decomposition device 2 from the cleaning liquid, and the oxygen gas is nitrogen supplied from the extraction gas supply device 5. It is designed to be extracted with an extraction gas such as. Then, in the extraction device 4, the oxygen gas extracted by the extraction gas is sent to the flow path 22A provided in the upper part of the reaction cell 22, while the cleaning liquid after the oxygen gas is extracted is used as a drain to cause the reaction. It is adapted to be discharged from a channel 22B provided in the lower portion of the cell 22.

On the other hand, the extraction gas supply device 5 has a flow rate adjusting valve for adjusting the flow rate of the extraction gas supplied from a gas supply source (not shown), and a flow meter for detecting the flow rate of the extraction gas, The opening degree of the flow rate adjusting valve is adjusted based on the measured value of the flow meter (increased / decreased within the range of 15% with respect to the average supply amount: described later). In the extraction device 4, the oxygen gas extracted by the extraction gas has its moisture removed by the dehumidifier 6 in the middle of the flow path 22B, and then the oxygen concentration in the extraction gas is detected by the oxygen detection means 7. It

The oxygen detecting means 7 comprises an oxygen sensor 23 for detecting the oxygen concentration and a preamplifier 24 for amplifying the detection signal of the oxygen sensor 23. The detection signal of the oxygen sensor 23 passed through the preamplifier 24. Are supplied to an amplitude detection circuit 9 described later through a cable. Further, in the fluid flow path system 100, the dehumidifier 6 is provided in the flow path 22A from which the extracted gas and the oxygen gas are discharged, and the gas flowing in the flow path 22A is dried. , Especially reaction cell 2
It may be omitted if water does not flow from the inside.
Further, although the extraction gas supply device 5 for supplying the extraction gas is provided in the middle of the flow path located between the thermal decomposition device 2 and the extraction device 4, the present invention is not limited to this, and the reaction cell 22 of the extraction device 4 is not limited to this.
The extraction gas may be directly supplied to.

Next, the amplitude detection circuit 9, the averaging circuit 10,
Control arithmetic circuit 11, alarm output circuit 12, alarm setting circuit 1
3, the control system 101 including the printer 14, the display unit 15, and the operation unit 16 will be described. Amplitude detection circuit 9
Is for capturing the detection signal output from the oxygen detection means 7 at a constant cycle (a, b, c, d, ...) And detecting the peak value of the detection signal from the captured detection signal, The detection signal indicating the peak value detected by the amplitude detection circuit 9 is output to the averaging circuit 10. The averaging circuit 10 detects the detection signal indicating the peak of the oxygen detecting means 7 detected by the amplitude detecting circuit 9 at a preset time interval (for example, timings a to g,
The averaged detection signal is output to the control arithmetic circuit 11 described later. In the present embodiment, the amplitude detection circuit 9 detects the plus side peak value of the detection signal output from the oxygen detection means 7.

The control arithmetic circuit 11 outputs drive signals for driving the suction device 1, the diluting device 3 and the extraction gas supply device 5, respectively. The concentration of hydrogen peroxide in the cleaning liquid is changed by adjusting the flow rate of the cleaning liquid supplied by the device 1, the flow rate of the diluting liquid supplied by the diluting device 3, and the flow rate of the extraction gas supplied by the extraction gas supply device 5. (By the density changing means provided in the control arithmetic circuit 11). The ratio of increasing / decreasing the flow rates of the cleaning liquid, the diluent, and the extraction gas is set based on the operation content of the operation unit 16.

The control arithmetic circuit 11 calculates the hydrogen peroxide concentration in the cleaning liquid based on the cleaning liquid flow rate, the diluting liquid flow rate, the extraction gas flow rate, and the detection signal from the oxygen detecting means 7. , And outputs the calculation result as an output signal to the printer 14 and the display unit 15, respectively. In the printer 14 and the display unit 15, a unit system, such as% or g, which the operator can recognize / understand based on the output signal from the control arithmetic circuit 11.
It is designed to print and display in units of / L.

On the other hand, the detection signal of the amplitude detection circuit 9 and the detection signal of the averaging circuit 10 are output to the control arithmetic circuit 11. The control calculation circuit 11 supplies the detection signal and the detection signal to the alarm output circuit 12, and the alarm output circuit 12 determines whether or not the output of the oxygen sensor 23 is abnormal based on the detection signal and the detection signal. (Alarm output circuit 12
By the second judgment means provided in). That is, in the alarm output circuit 12, the ratio between the detection signal of the averaging circuit 10 supplied through the control arithmetic circuit 11 and the fluctuation width (peak value) of the detection signal of the amplitude detection circuit 9 is the alarm setting circuit 1
3. The threshold value set by the alarm setting circuit 13 is compared and judged (by the second judgment means provided in the alarm output circuit 12) by comparing whether or not it is larger than the upper limit threshold value and the lower limit density threshold value set in 3. Depending on whether or not the value is exceeded, an alarm indicating an abnormality is output to notify the operator of the abnormality (by the abnormality detecting means provided in the alarm output circuit 12). The threshold value set by the alarm setting circuit 13 is appropriately changed according to the operation content of the operation unit 16, for example.

Next, the control contents of the arithmetic control circuit 11 in the normal operation mode and the sensor diagnosis mode will be described. << Normal Operation Mode >> The operation control circuit 11 outputs drive signals for driving the suction device 1, the diluting device 3, and the extraction gas supply device 5, respectively. In the normal operation mode, the fluid flow rates of the suction device 1, the diluting device 3, and the extraction gas supply device 5 are set to constant amounts without changing. Then, such suction device 1, diluting device 3,
By driving the extraction gas supply device 5, a cleaning liquid containing hydrogen peroxide as an active ingredient is introduced into the thermal decomposition device 2, heated in the thermal decomposition device 2, and heated in the thermal decomposition device 2 and filled with the catalyst. Hydrogen peroxide is decomposed into oxygen and water. Further, the oxygen gas obtained in the thermal decomposition apparatus 2 is supplied to the extraction apparatus 4 together with the extraction gas supplied from the extraction gas supply apparatus 5, and is gas-liquid separated from the cleaning liquid in the extraction apparatus 4 to detect oxygen. The concentration is measured by the oxygen sensor 23 of the means 7, and further the preamplifier 24
At, the linearity and the gain of the detection signal indicating the oxygen concentration of the oxygen sensor 23 are corrected.

The oxygen sensor 2 that has passed through the preamplifier 24
The detection signal of No. 3 is supplied to the control calculation circuit 11 via the amplitude detection circuit 9 and the averaging circuit 10, and further, in the control calculation circuit 11, the hydrogen peroxide contained in the cleaning liquid based on the detection signal. The ratio (% density, g / L) is calculated and output to the printer 14 and the display unit 15 in real time. In the normal operation mode, since the suction device 1, the diluting device 3, and the extraction gas supply device 5 are continuously operated, the detection signal of the oxygen sensor 23 does not change. In such a case,
In the amplitude detection circuit 9 and the averaging circuit 10, the oxygen sensor 23
The detection signal of 1 is supplied to the control arithmetic circuit 11 as it is without being processed. On the other hand, the detection signal and the detection signal detected based on the output of the oxygen sensor 23 are supplied to the alarm output circuit 12, and the alarm output circuit 12 detects the detection signal of the averaging circuit 10 and the detection signal of the amplitude detection circuit 9. Whether the ratio to the fluctuation range (peak value) of is larger than the upper limit concentration threshold (for example, 20%) set by the alarm setting circuit 13 or larger than the lower limit concentration threshold (for example, 10%). If the oxygen concentration is higher than the upper limit concentration threshold or lower than the lower limit concentration threshold as a result of the determination, an alarm alarm is output to let the operator check the cleaning liquid. To do. Needless to say, the upper limit concentration threshold of 20% and the lower limit concentration threshold of 10% set by the alarm setting circuit 13 can be arbitrarily changed.

<< Sensor diagnosis mode >> Next, the oxygen sensor 23 is changed by changing the content ratio of hydrogen peroxide to the cleaning liquid.
Sensor diagnostic mode (I) for checking the detection signal of No. 2, the content rate of oxygen generated from hydrogen peroxide is changed by changing the flow rate of the extraction gas of the extraction gas supply device 5, and the detection signal of the oxygen sensor 23 is changed. The sensor diagnosis mode (II) for checking will be described.

First, the sensor diagnosis mode (I) will be described. The concentration of hydrogen peroxide supplied to the heating / decomposition device 2 is supplied by the flow rate of the cleaning liquid supplied by the suction device 1 and the extraction gas supply device 5. When the flow rate of the extracted gas is constant, it changes according to the flow rate of the diluting liquid supplied by the diluting device 3. That is, the oxygen concentration (hydrogen peroxide concentration) detected by the oxygen sensor 23 decreases as the flow rate of the diluting device 3 increases, and increases as the flow rate of the diluting device 3 decreases. It is proportional to the dilution ratio of the cleaning solution with the diluent. And this dilution ratio is
It is a value obtained by dividing the flow rate of the suction device 1 by the total flow rate of the suction device 1 and the diluting device 3. To obtain the concentration of hydrogen peroxide sucked into the suction device 1, the oxygen sensor 23 detects the concentration. It is sufficient to multiply the concentration of the hydrogen peroxide thus generated by this dilution ratio. Therefore, when the diluting device 3 changes the supply amount of the diluting liquid, the detected concentration of the oxygen sensor 23 also changes according to the change amount, and the sensor diagnosis as shown in FIG. I do.

First, in FIG. 2, reference numeral 30 is a liquid exchange signal indicating whether or not the inside of a cleaning tank (not shown) as a supply source of the supply of cleaning liquid is empty. "L" indicates that the cleaning liquid in the cleaning tank is being replaced,
At this time, since the suction device 1 may suck air, the function of analyzing the cleaning liquid is stopped, while "H" of the liquid exchange signal 30 indicates that a certain amount or more of the cleaning liquid is stored in the cleaning liquid. The cleaning solution can be analyzed at this time and sampling is permitted.

Reference numeral 31 indicates a control signal for driving and stopping the suction device 1,
When it is “H”, the suction device 1 is driven, and when it is “L”, the suction device 1 is stopped. By switching such “H” and “L”, the cleaning liquid of a predetermined flow rate can be obtained. It can be supplied. The reference numeral 32 indicates a control signal for driving and stopping the diluting device 3, and drives the diluting device 3 when it is “H” and stops the diluting device 3 when it is “L”. By switching between such "H" and "L", it is possible to supply the diluent at a predetermined flow rate.

The reference numeral 33 indicates the actual intake amount of hydrogen peroxide contained in the cleaning liquid diluted by switching the control signals "H" and "L". Reference numeral 34 indicates a detection signal of the oxygen sensor 23 which detects oxygen generated at the time when hydrogen peroxide in the cleaning liquid whose concentration has been adjusted by switching the control signals "H" and "L" is decomposed. The reference numeral 35 indicates
It shows the ratio of the peak value (detection signal) on the plus side of the oxygen sensor 23 to the average value (detection signal). 36
Indicates an average value of the detection signal of the oxygen sensor 23, reference numeral 37 is an alarm output of the alarm output circuit 12, "H" is an output when an abnormality occurs, and "L" is normal. The output for each case is shown.

In the sensor diagnostic mode (I) of this embodiment, as shown in FIG. 2, the liquid exchange signal changes from "L" to "H" at the timing a, and the exchange of the cleaning liquid is completed. Is detected, the suction device 1 and the diluting device 3 are intermittently driven and stopped as indicated by the reference numeral (a), and the flow rate of the diluting liquid for diluting the washing liquid is changed to the average flow rate of the washing liquid (100%). ) Within ± 15%. As a result, as shown by reference numerals 33 and 34, the intake amount of hydrogen peroxide contained in the cleaning liquid and the oxygen concentration generated from hydrogen peroxide are also changed within a range of ± 15%. At this time, the ratio of the peak value and the average value on the plus side of the oxygen sensor 23, which is indicated by reference numeral 35, is 15%.
If it is not in the vicinity (denoted by the symbol (b)), the alarm signal 37 of "H" indicating an abnormality is output (denoted by the symbol (c)).

That is, the alarm output circuit 12 is operated to operate the alarm setting circuit 13 so that the upper limit concentration threshold of 18%,
The lower limit concentration threshold value of 12% is set in advance, and further, in the alarm output circuit 12, the upper limit and lower limit concentration threshold values and the oxygen sensor 23 indicated by reference numeral 35.
When it is determined that the ratio of the positive peak value to the average value on the positive side is between 18% for the upper concentration threshold and 12% for the lower concentration threshold, the alarm signal 37 of the alarm output circuit 12 is output.
Outputs "L" indicating normality (indicated by symbol (d)), and when it is determined that the upper limit concentration threshold value is 18% or more or the lower limit concentration threshold value is 12% or less, an alarm is output. The alarm signal 37 of the circuit 12 outputs "H" indicating an abnormality (indicated by a symbol (c)).

The upper limit concentration threshold and the lower limit concentration threshold of the alarm output circuit 12 set by the alarm setting circuit 13 are set to 18% and 12%, respectively. ± the average flow rate of the cleaning solution (100%)
It corresponds to the increase of 15%,
Needless to say, when the change amount of the diluting liquid is further changed, the alarm setting circuit 13 also changes the setting of the upper limit concentration threshold and the lower limit concentration threshold.

Next, the sensor diagnosis mode (II) will be described in which the flow rate of the extraction gas is changed and it is diagnosed whether or not the output of the oxygen sensor 23 changes equally with the change in the flow rate of the extraction gas. . First, the outline of the sensor diagnosis mode (II) will be described. When the extraction gas supply device 5 supplies a large amount of extraction gas even if the flow rates of the cleaning liquid and the diluent liquid supplied to the heating / decomposition device 2 are constant, The oxygen concentration supplied to the oxygen sensor 23 decreases, and the flow rate of the extracted gas and the oxygen concentration have an inverse relationship. Therefore, by dividing the oxygen concentration obtained from the oxygen sensor 23 by the flow rate of the extraction gas, the concentration of hydrogen peroxide actually supplied to the heating / decomposing device 2 can be obtained. Therefore, if the flow rate of the extracted gas from the extracted gas supply device 5 is changed, the detected concentration of the oxygen sensor 23 also changes according to this change amount, and the sensor as shown in FIG. Make a diagnosis. In addition, in the time chart of FIG.
The same parts as those in FIG. 2 are designated by the same reference numerals to simplify the overlapping description.

The reference numeral 40 in FIG. 3 indicates the average value (100) of the extraction gas supplied from the extraction gas supply device 5.
%), And in this embodiment, the flow rate of the extracted gas is changed within a range of ± 15% with respect to the average value. Then, in such a sensor diagnosis mode (II), as shown in FIG. 3, the liquid exchange signal changes from "L" to "H" at timing a, and it is detected that the exchange of the cleaning liquid is completed. When,
As indicated by the symbol (e), the flow rate of the extraction gas supplied from the extraction gas supply device 5 is ± with respect to the average value (100%).
When the oxygen concentration is changed within the range of 15%, the oxygen concentration generated from hydrogen peroxide also changes as indicated by reference numeral 34, but at this time, the oxygen sensor 23 indicated by reference numeral 35 changes. The ratio of the positive peak value to the average value is 15
If it is not around%, the alarm signal 37 of "H" indicating an abnormality is output.

That is, in the alarm output circuit 12, the ratio of the peak value on the plus side of the oxygen sensor 23 to the average value is 18% for the upper limit concentration threshold or 12% for the lower limit concentration threshold.
It is judged whether or not it is within the same range as the sensor diagnosis mode (I), and if these threshold values are between 18% and 12%, the alarm signal 37 of the alarm output circuit 12 is determined.
Is designated as “L” indicating normality (indicated by a symbol (f)), and
When the upper limit concentration threshold value is 18% or more or the lower limit concentration threshold value is 12% or less, the alarm signal 37 of the alarm output circuit 12 is set to "H" indicating an abnormality (indicated by a symbol (g)). ).

The sensor diagnosis mode (I) of this embodiment
In the above, the flow rate of the diluting liquid for diluting the cleaning liquid is changed within a range of ± 15% with respect to the average flow rate (100%) of the cleaning liquid. The setting can be arbitrarily changed by changing the drive time of the pump of the diluting device 3. In this case, in a pump having a rotation system such as an induction motor, the flow rate supplied from the pump can be changed by changing the driving frequency, not the driving time. It may be used for the pump of, and a pump that discharges a constant flow rate,
Needless to say, the flow rate may be controlled in combination with a valve. In the sensor diagnosis mode (II), the flow rate of the extraction gas supplied from the extraction gas supply device 5 is changed within the range of ± 15% with respect to the average supply amount. As for the above, the setting can be arbitrarily changed by changing the opening degree of the flow rate adjusting valve in the extraction gas supply device 5.

In the sensor diagnosis mode (II), the upper limit concentration threshold of the alarm output circuit 12 set by the alarm setting circuit 13 is set to 18% and the lower limit concentration threshold is set to 12%. The threshold value corresponds to the fact that the flow rates of the diluent and the extraction gas are changed within a range of ± 15% with respect to the average value, and when the change amount of ± 15% is further changed, It goes without saying that the alarm setting circuit 13 also changes the upper and lower density thresholds.

As described above in detail, in the liquid management apparatus according to the present embodiment, the concentration of hydrogen peroxide in the cleaning liquid is changed in the sensor diagnosis mode (I), and the oxygen sensor is tracked according to this change in concentration. It is tested whether or not the detection signal of 23 changes, and in the sensor diagnostic mode (II), the flow rate of the extraction gas supplied from the extraction gas supply device 5 is changed to determine the oxygen concentration in the extraction gas. The oxygen sensor 23 is changed to test whether the detection signal of the oxygen sensor 23 changes in accordance with the change in the concentration, and the oxygen sensor 23 is tested according to the test result.
Can function correctly. Therefore, in the liquid management apparatus of the above-described embodiment, the function of the oxygen sensor 23 can be checked according to the diagnostic results of the sensor diagnostic modes (I) and (II). Therefore, the oxygen sensor 23 is used to determine the concentration of the effective component in the cleaning liquid. Can be measured accurately,
It is possible to accurately know when to replace the cleaning liquid, and thus it is possible to prevent defects such as defective cleaning of the wafer.

Further, in the above embodiment, the abnormality setting circuit 13
Set the upper density threshold and the lower density threshold with
When the output level of the oxygen sensor 23 deviates from these threshold values, it is determined that the abnormality is present. Therefore, according to the content of the threshold value set by the abnormality setting circuit 13, the determination for determining the abnormality is made. It is possible to change the standard as appropriate, which makes it possible to easily adjust the detection accuracy of the liquid management apparatus. Further, in the above embodiment, the concentration of hydrogen peroxide in the cleaning liquid is changed in the sensor diagnosis mode (I), and it is tested whether or not the detection signal of the oxygen sensor 23 changes in accordance with the change in the concentration. Further, in the sensor diagnosis mode (II), the flow rate of the extraction gas supplied from the extraction gas supply device 5 is changed to change the oxygen concentration in the extraction gas, and the oxygen sensor is tracked according to the change in the concentration. Although it was tested whether the detection signal of 23 changed, a specific ratio was set for such a change in the concentration of hydrogen peroxide in the cleaning liquid and a change in the flow rate of the extracted gas, and the output of the oxygen sensor 23 was set according to this ratio. It is possible to observe in detail the degree of abnormality of the oxygen sensor 23.

In the above embodiment, two sensor diagnostic modes (I) and (II) are provided, but which of these sensor diagnostic modes (I) and (II) is selected is operated. It is based on an instruction from the section 16. Further, in the above-described embodiment, the circuits shown in FIGS. 2 and 3 use analog circuits or digital circuits, but amplitude measurement and threshold values are set in the memory device of the microcomputer, and the oxygen concentration can be adjusted according to the oxygen concentration. The conversion to hydrogen oxide concentration, concentration display, and alarm output may be executed by a microcomputer.

Further, in the above embodiment, the liquid management device for detecting the concentration of the effective components of hydrogen peroxide and ozone in the cleaning liquid used at the time of manufacturing the semiconductor has been described, but the present invention is not limited to this, and such liquid is used. The management device may be used in an agricultural facility such as a vegetable factory to detect the concentration of effective components of hydrogen peroxide and ozone in the cleaning liquid used for sterilization and cleaning. In the above embodiment, the liquid exchange signal is "L".
The sensor diagnostic modes (I) and (II) are executed on the condition that the change from "H" to "H" occurs. At this time, the active ingredients in the cleaning solution, such as hydrochloric acid and hydrogen peroxide, and sulfuric acid Immediately after mixing hydrogen peroxide, ammonia, and hydrogen peroxide, the hydrogen peroxide concentration does not show a steady value, so it is advisable to wait for a certain period of time to execute these sensor diagnostic modes (I) and (II).

Further, in the above-mentioned embodiment, the liquid management apparatus of the type in which the effective component concentration is calculated based on the oxygen concentration generated by decomposing the effective component has been described, but the present invention is not limited to this, and the redox electrode The redox electrode can be similarly diagnosed in the liquid management device of the type in which the effective component concentration is calculated based on the detected value. That is, for example, by diluting and supplying a diluting liquid in a range of 15% to the cleaning liquid sampled by a certain amount, and diagnosing whether or not the detection value of the electrode correctly changes in accordance with this, the present embodiment Similarly, the function of the electrode may be confirmed.

The process of changing the content ratio of hydrogen peroxide to the cleaning liquid or changing the flow rate of the extraction gas of the extraction gas supply device 5 and thereby changing the hydrogen peroxide ratio is performed by the control arithmetic circuit 11. The “concentration changing means” provided is provided in the alarm output circuit 12 to determine whether the output of the oxygen sensor 23 changes when the ratio of hydrogen peroxide, which is an active ingredient, is changed. The second judging means ". Further, when it is determined that the output of the oxygen sensor 23 does not change even if the concentration of hydrogen peroxide changes, it is determined that the oxygen sensor 23 is abnormal by the "abnormality detection" provided in the alarm output circuit 12. Means.

[0040]

As described in detail above, according to the present invention,
When the concentration changing means changes the concentration of the active ingredient in the solution, the second determining means determines whether or not the concentration in the solution detected by the detecting means changes. Further, when the second judging means judges that the detected concentration of the detecting means does not change even when the concentration of the active ingredient in the solution is changed by the concentration changing means, the abnormality detecting means determines that the detecting means does not change. It is determined that there is something wrong with. That is, in the present invention, it is possible to know whether or not the detection means is functioning normally based on the abnormality determination result of such an abnormality detection means, and when the solution is used for cleaning the wafer, etc. In, it is possible to accurately know the replacement time of the solution.

[Brief description of drawings]

FIG. 1 is a diagram showing a fluid flow channel system 100 and a control system 101.

FIG. 2 is a diagram showing a time chart of a sensor diagnosis mode (I).

FIG. 3 is a diagram showing a time chart of a sensor diagnosis mode (II).

[Explanation of symbols]

1 Suction Device 2 Heating / Decomposing Device 3 Diluting Device 4 Extraction Device 5 Extraction Gas Supply Device 6 Dehumidifier 7 Oxygen Detection Means (Detection Means) 9 Amplitude Detection Circuit 10 Averaging Circuit 11 Control Arithmetic Circuit (Concentration Change Means) 12 Alarm Output Circuit (second judgment means / abnormality detection means)
(Informing means) 13 alarm setting circuit 14 printer 15 display unit 16 operation unit 23 oxygen sensor 100 fluid flow channel system 101 control system

Claims (1)

[Claims] 1. A detection means for detecting the concentration of an active ingredient in a solution, a lower limit storage means for storing a lower limit value of the active ingredient in the solution, and a lower limit value storage means for detecting the concentration in the solution detected by the detection means. First determining means for determining whether or not the concentration of the active ingredient is lower than the lower limit stored in the lower limit storage means, and the lower limit of the concentration of the active ingredient in the solution stored in the lower limit storage means When the first determination means determines that the value is lower than the value, an informing means for informing this, a concentration changing means for changing the concentration of the active ingredient in the solution in the liquid management device, When the concentration of the active ingredient in the solution is changed by the concentration changing unit, a second determining unit that determines whether the concentration detected by the detecting unit changes, and the solution by the concentration changing unit Effective in If the second determining means determines that the concentration detected by the detecting means does not change even if the concentration of the minute is changed, an abnormality detecting means for detecting an abnormality of the detecting means is provided. Characteristic liquid management device.