JP6095887B2 - Liquid management system - Google Patents

Description

The present invention relates to a system for managing semiconductor wafer or an LCD (Liquid Crystal Display) substrate, a liquid used in the washing and drying of such MEMS (Micro Electro Mechanical Systems).

  For cleaning and drying of a semiconductor wafer or the like, an alcohol aqueous solution that is a mixture of alcohol and water may be used. Patent Document 1 describes a semiconductor wafer cleaning / drying apparatus using a liquid obtained by mixing isopropyl alcohol (IPA (isopropyl alcohol)) and ultrapure water as a cleaning liquid. Specifically, the apparatus described in Patent Document 1 includes a processing tank in which wafers are cleaned and dried, a cleaning liquid mixing unit that adjusts a cleaning liquid supplied to the processing tank to a predetermined concentration in advance, and a cleaning liquid mixing unit. And a cleaning liquid supply section for moving the cleaning liquid from the cleaning tank to the cleaning tank.

  The cleaning liquid mixing unit includes an IPA tank and a mixing tank connected to the IPA tank. The mixing tank is also connected to a supply source of ultrapure water provided outside. Furthermore, an IPA replenishment pump is provided in the middle of the pipe connecting the IPA tank and the mixing tank. On the other hand, the cleaning liquid supply unit is provided with an IPA concentration meter that measures the IPA concentration in the cleaning liquid supplied to the treatment tank.

  In the apparatus described in Patent Document 1 having the above-described configuration, a predetermined amount of IPA and ultrapure water are independently supplied to the mixing tank, and a cleaning liquid having a predetermined concentration is produced. Then, the cleaning liquid in the mixing tank is supplied to the treatment tank via the cleaning liquid supply unit.

  Here, when a decrease in the IPA concentration in the cleaning liquid is detected by the IPA densitometer, the IPA replenishment pump is activated, and IPA is additionally supplied from the IPA tank to the mixing tank. That is, the IPA concentration is adjusted by replenishing IPA.

Japanese Patent Laying-Open No. 2003-29795 ([0023] to [0027], [0037] to [0038], FIG. 1)

  In cleaning a semiconductor wafer or the like, it is ideal that a cleaning solution having a constant IPA concentration is always circulated in a predetermined amount. That is, it is ideal that the amount (liquid level) of the cleaning liquid in the mixing tank is maintained within a certain range. However, in practice, the liquid level in the mixing tank changes. For example, not only IPA but also water evaporates from the cleaning liquid circulating in the system. Also, part of the cleaning liquid may adhere to the wafer to be cleaned and be taken out of the system. In such a case, the liquid level of the cleaning liquid in the mixing tank decreases. On the other hand, moisture may adhere to the wafer to be cleaned and be brought into the system. In this case, the liquid level of the cleaning liquid in the mixing tank rises. In this regard, in the semiconductor wafer cleaning / drying apparatus described in Patent Document 1, the liquid level of the cleaning liquid in the mixing tank is not managed. Therefore, in the semiconductor wafer cleaning / drying apparatus described in Patent Document 1, the amount (liquid level) of the cleaning liquid in the mixing tank is not considered when adjusting the concentration of the cleaning liquid. However, if the cleaning liquid concentration is adjusted when the level of the cleaning liquid in the mixing tank is rising, that is, when the amount of the cleaning liquid in the system is increasing, the amount of IPA required for concentration adjustment increases. End up. Note that a plurality of level sensors are provided in the mixing tank in the semiconductor wafer cleaning / drying apparatus described in Patent Document 1, but the level sensors are used for the amount of ultrapure water supplied to the mixing tank. However, it is not for managing the amount (liquid level) of the cleaning liquid in which ultrapure water and IPA are mixed.

  In the semiconductor wafer cleaning / drying apparatus described in Patent Document 1, the concentration of the cleaning liquid is adjusted by replenishment with IPA. However, if the IPA concentration exceeds a predetermined value, this cannot be recovered. Therefore, when adjusting the concentration of the cleaning liquid, it is necessary to gradually approach the predetermined concentration while repeating the replenishment of IPA and the concentration measurement many times so that the IPA concentration does not exceed the predetermined value. The amount of replenishment must be small. In general, it takes time and labor to adjust the concentration of the cleaning solution. In particular, in cleaning a semiconductor wafer, it is necessary to manage the concentration of the cleaning liquid with high accuracy, and thus adjusting the concentration of the cleaning liquid requires a great amount of time and labor.

  Furthermore, Patent Document 1 describes that a plurality of mixing tanks that can be used by alternately switching are provided. However, if the mixing tank is switched without stopping the circulation of the cleaning liquid, a stable supply of the cleaning liquid becomes difficult because the amount of the circulating liquid changes before and after the switching. In addition, since the cleaning liquid is switched before and after the switching of the mixing tank, the state of the cleaning liquid (concentration, temperature, contamination state, etc.) may change, and the process (cleaning, drying) may be affected.

  The present invention has been made in view of the above problems, and its purpose is to maintain the alcohol concentration in a cleaning liquid containing alcohol and pure water within a certain range and to add alcohol for concentration adjustment. It is to reduce the amount used.

  As one aspect of the present invention, a liquid management system for managing a cleaning liquid used in a cleaning apparatus for cleaning an object is provided.

This liquid management system is a liquid management system that manages a cleaning liquid used in a cleaning device that cleans an object. The liquid management system mixes alcohol and pure water to produce a cleaning liquid, and the alcohol concentration in the cleaning liquid by the mixing means. A concentration adjusting means for adjusting the concentration within a predetermined concentration range, and a line for recovering the cleaning liquid discharged from the cleaning apparatus and returning it to the mixing means, and a circulation line for circulating the cleaning liquid between the mixing means and the cleaning apparatus. And a concentrator which is provided on the line returning to the mixing means and concentrates the alcohol in the cleaning liquid discharged from the cleaning device. The concentration adjusting means includes an alcohol supply means for supplying alcohol to the mixing means, a pure water supply means for supplying pure water to the mixing means, a concentration measuring means for measuring the alcohol concentration of the cleaning liquid in the mixing means, and a concentration measuring means By controlling both or one of the alcohol supply means and the pure water supply means based on the measurement result, the alcohol concentration of the cleaning liquid in the mixing means falls within a predetermined concentration range during the circulation of the cleaning liquid along the line returning to the mixing means. And a first control means for executing density adjustment processing to be maintained at the same level.

  According to the present invention, the alcohol concentration in the cleaning liquid containing alcohol and pure water can be maintained within a certain range. In addition, the amount of alcohol added for concentration adjustment can be reduced by collecting, concentrating and returning the cleaning liquid discharged from the cleaning device to the mixing means. Furthermore, since the concentration of the cleaning liquid that returns to the mixing means can be kept within a certain range, the concentration of the cleaning liquid can be adjusted with higher accuracy.

The block diagram which shows 1st embodiment of this invention. The block diagram which shows 2nd embodiment of this invention. The block diagram which shows 3rd embodiment of this invention. The block diagram which shows 4th embodiment of this invention. The block diagram which shows 5th embodiment of this invention.

(First embodiment)
Hereinafter, the first embodiment of the present invention will be described in detail. FIG. 1 is a block diagram showing a basic configuration of a liquid management system according to the present embodiment.

  As shown in FIG. 1, a liquid management system 1 </ b> A according to the present embodiment is connected to a semiconductor wafer cleaning apparatus 100 and supplies a cleaning / drying liquid to the cleaning apparatus 100. Although a detailed description of the cleaning device 100 is omitted here, the cleaning device 100 includes at least a cleaning tank that cleans the semiconductor wafer using the cleaning / drying liquid supplied from the liquid management system 1A.

  As shown in FIG. 1, the liquid management system 1A is generically referred to as a cleaning / drying liquid (hereinafter referred to as “cleaning liquid”) in which alcohol (IPA in this embodiment) and pure water (ultra pure water in this embodiment) are mixed. ) Prepared, alcohol supply means for supplying IPA to the mixing tank 4, pure water supply means for supplying ultrapure water to the mixing tank 4, and concentration measuring means connected to the mixing tank 4 ( It has a concentration measuring device 5), a waste liquid tank 6, and a control unit 7 for comprehensively controlling the system 1A.

  The above-described alcohol supply means has at least the IPA supply source 2, the pipe 10, and the valve 15a shown in FIG.

  The IPA supply source 2 includes, for example, a container in which IPA is stored, and a unit that pumps the IPA in the container to the mixing tank 4. Specific examples of means for pumping IPA include gas pressurization and a pump. The pipe 10 connects the IPA supply source 2 and the mixing tank 4, and forms a flow path for introducing IPA from the IPA supply source 2 to the mixing tank 4. The valve 15 a is provided in the pipe 10 and is controlled by the control unit 7 to adjust the start or stop of IPA introduction, the amount of IPA introduction, and the like.

  The pure water supply means described above has at least the ultrapure water supply source 3, the pipe 11 and the valve 15b shown in FIG.

  The pipe 11 connects the ultrapure water supply source 3 and the mixing tank 4, and forms a flow path for introducing ultrapure water from the ultrapure water supply source 3 to the mixing tank 4. The valve 15 b is provided in the pipe 11 and is controlled by the control unit 7, and adjusts the start or stop of introduction of ultrapure water, the introduction amount of ultrapure water, and the like. The ultrapure water supply source 3 may be an ultrapure water production apparatus that is directly connected to the mixing tank 4 via the pipe 11. The ultrapure water supply source 3 pumps a tank for storing ultrapure water produced by the ultrapure water production apparatus and the ultrapure water stored in the tank to the mixing tank 4 via the pipe 11. You may have a pump etc.

In order to make the concentration of the cleaning liquid in the mixing tank 4 immediately after the supply of IPA and ultrapure water uniform, the mixing tank 4 is preferably provided with a stirring mechanism. For example, circulation of cleaning liquid by a pump or the like, gas ( N ₂ or the like) is preferably blown in and stirred. Moreover, a line mixer may be provided in the front stage of the mixing tank 4, and the cleaning liquid mixed via the line mixer may be stored in the mixing tank 4 by joining the pipe 10 and the pipe 11. Further, a line mixer may be provided instead of the mixing tank 4 and the cleaning liquid mixed by the line mixer may be directly supplied to the cleaning device 100. Therefore, the mixing means referred to in the claims includes not only the mixing tank but also other types.

  The mixing tank 4 and the concentration measuring means (concentration measuring device 5) are connected to each other via a pipe 12. The mixing tank 4 and the waste liquid tank 6 are connected to each other via a pipe 13.

  And the mixing tank 4 and the washing | cleaning apparatus 100 are mutually connected via the piping 14a, and the cleaning liquid adjusted in density | concentration from the mixing tank 4 is sent to the washing | cleaning apparatus 100 by the 1st liquid feeding means containing the piping 14a. Here, the component concentration of the cleaning liquid in the mixing tank 4 and the component concentration of the cleaning liquid immediately after flowing out of the mixing tank 4 are substantially the same. Therefore, the component concentration of the cleaning liquid in the mixing tank 4 can be measured both when the concentration measuring device 5 is provided on the pipe 14a and when the concentration measuring device 5 is connected to a pipe (not shown) branched from the pipe 14a. Is possible. That is, the measurement of the cleaning liquid component concentration in the present invention includes both the measurement of the cleaning liquid component concentration in the mixing tank 4 and the measurement of the cleaning liquid component concentration immediately after flowing out of the mixing tank 4.

  Furthermore, the liquid management system 1 </ b> A includes a concentrator 16 that concentrates the cleaning liquid discharged from the cleaning device 100 and returns it to the mixing tank 4. For this reason, the cleaning apparatus 100 and the concentrator 16 are connected to each other via the pipe 14b, and the cleaning liquid discharged from the cleaning apparatus 100 is sent to the concentrator 16 by the second liquid feeding means including the pipe 14b. Furthermore, the mixing tank 4 and the concentrator 16 are connected to each other via the pipe 14c, and the cleaning liquid concentrated in the concentrator 16 is sent to the mixing tank 4 by the third liquid feeding means including the pipe 14c. The waste liquid tank 6 and the concentrator 16 are connected to each other via a pipe 14d, and the waste liquid discharged from the concentrator 16 is sent to the waste liquid tank 6 by the fourth liquid feeding means including the pipe 14d. Each liquid feeding means is provided with a pump or the like that causes a liquid flow in a target direction as required.

  For the concentrating means of the concentrator 16, it is preferable to apply a membrane separation technique such as an osmotic vaporization method (PV method; Pervaporation) or an evaporation permeation method (VP method; Vapor Permeation). The PV method is preferable in that the heat source can be reduced. On the other hand, the VP method can be concentrated with a small size and high efficiency of the apparatus. Existing films can be used for the PV method and VP method. For example, there are membranes made of inorganic materials such as zeolite, polyimide materials, cellulose materials, and polyvinyl alcohol materials.

  Zeolite is excellent in mechanical strength, dehydration performance, and heat resistance, and can be concentrated with high efficiency. However, since the water resistance is low, it is suitable for processing a liquid having an IPA concentration of 80% or more. In addition, when the elution from the zeolite is particularly concerned, it is preferable to apply the VP method. A film made of a polymer such as polyimide is more water resistant than zeolite and can be processed even if the IPA concentration is about 60%.

  Next, the operation of the liquid management system 1A having the above configuration will be described. First, the control unit 7 opens the valves 15a and 15b shown in FIG. 1 simultaneously or sequentially and supplies IPA and ultrapure water from the IPA supply source 2 and the ultrapure water supply source 3 to the mixing tank 4. . Here, IPA and ultrapure water are supplied at a predetermined rate. In other words, a predetermined amount of IPA and ultrapure water are respectively supplied so as to obtain a cleaning liquid having an ideal component concentration (hereinafter referred to as “ideal concentration”). Thereby, IPA and ultrapure water are mixed in the mixing tank 4 to produce a cleaning liquid. However, at this time, the component concentration of the cleaning liquid in the mixing tank 4 does not always completely match the ideal concentration. This is because IPA and ultrapure water are supplied to the mixing tank 4 at a constant rate, but this rate is a calculated rate.

When IPA and ultrapure water are supplied to the mixing tank 4 to produce a predetermined amount of cleaning liquid, the valves 15a and 15b are closed. Next, the density adjustment process is started. Specifically, a part of the cleaning liquid in the mixing tank 4 is extracted via the pipe 12 under the control of the control unit 7, and the concentration of the component is measured by the concentration measuring device 5. Thereafter, both or one of the valve 15a and the valve 15b are opened again according to the measurement result by the concentration measuring device 5, and both the IPA supply source 2 and the ultrapure water supply source 3 are used. Both or one is replenished to the mixing tank 4. More specifically, the concentration measurement by the concentration measuring device 5 and the replenishment of IPA and / or ultrapure water are repeated several times so that the component concentration of the cleaning liquid in the mixing tank 4 matches the ideal concentration. Further, the supply of IPA and ultrapure water to the mixing tank 4 for producing a predetermined amount of cleaning liquid and the concentration adjustment process can be performed simultaneously. Specifically, while supplying IPA and ultrapure water to the mixing tank 4, a part of the cleaning liquid in the mixing tank 4 is extracted to measure the component concentration, and both the valve 15a and the valve 15b are measured according to the measurement result. Or one side may be opened and closed, and an opening degree may be adjusted. Anyway, the control part 7 in this embodiment functions as a 1st control means of the invention which concerns on Claim 1 of this application.

  The cleaning liquid extracted for the concentration measurement is returned to the mixing tank 4 or discarded (may be sent to the waste liquid tank 6 or discharged through another line) depending on the degree of contamination. When the concentration measuring device 5 is branched from the pipe 14 a and connected, it may be returned to the pipe 14 a or sent to the cleaning device 100. However, when a Karl Fischer moisture meter is used as the concentration measuring device 5, it is necessary to use a reagent for the cleaning liquid. Therefore, it is preferable to discard the cleaning liquid after the concentration measurement.

  When a cleaning liquid having an ideal concentration or a concentration close thereto is prepared as described above, supply of the cleaning liquid from the mixing tank 4 to the cleaning apparatus 100 and recovery of the cleaning liquid from the cleaning apparatus 100 to the mixing tank 4 are started. . Specifically, pipes 14a, 14b, and 14c are provided so that the cleaning liquid circulates again from the mixing tank 4 through the cleaning device 100 and the concentrator 16 to the mixing tank 4, and first, the concentration in the mixing tank 4 The adjusted cleaning liquid is supplied to the cleaning tank of the cleaning apparatus 100 through the pipe 14a. Subsequently, the cleaning liquid discharged from the cleaning of the cleaning apparatus 100 is sent to the concentrator 16 through the pipe 14b.

  In the cleaning tank, the IPA concentration and the amount of impurities of the cleaning liquid in the cleaning tank differ in the process of cleaning the wafer due to the influence of the cleaning liquid and moisture taken out or brought in as wafer deposits or evaporation. In general, however, the IPA concentration of the cleaning liquid discharged from the cleaning apparatus 100 is reduced as compared with the IPA concentration of the cleaning liquid supplied from the mixing tank 4 to the cleaning apparatus 100 due to mixing of pure water, IPA evaporation, or the like. Therefore, IPA is concentrated by the concentrator 16.

  The concentrated liquid that has passed through the concentrator 16 is sent to the mixing tank 4 via the pipe 14 c, and the waste liquid that exits the concentrator 16 is sent to the waste liquid tank 6. In the mixing tank 4, the IPA concentration of the cleaning liquid is adjusted by the IPA supply means and the ultrapure water supply means, and the cleaning liquid whose concentration has been adjusted is sent to the cleaning device 100 again via the pipe 14a. In this way, the cleaning liquid is circulated from the mixing tank 4 to the mixing tank 4 again through the cleaning device 100 and the concentrator 16. Thereby, it is possible to supply the cleaning liquid of the ideal concentration to the cleaning apparatus 100 without stopping the cleaning process.

  As shown in Japanese Patent Application No. 2011-084456 and Japanese Patent Application No. 2011-084457, the applicant of the present invention uses only the supply pipe and the recovery pipe in the configuration shown in FIG. And a liquid management system that can maintain the concentration of the cleaning liquid within a certain range while circulating the cleaning liquid between the mixing tank 4 and the mixing tank 4.

  In these prior inventions, in order to maintain the concentration of the cleaning liquid (a liquid containing IPA and pure water) within a certain range, alcohol or pure water is supplied and controlled from the alcohol supply means and the pure water supply means. Yes. However, depending on the concentration condition of the cleaning liquid, the amount of alcohol or pure water required for concentration adjustment increases, the amount of cleaning liquid increases more than necessary, and the cleaning liquid (that is, alcohol and pure water) is prepared wastefully. The point was concerned.

  For example, when managing the IPA concentration of the cleaning liquid to 95%, the supply flow rate (average) to the cleaning apparatus 100 is 1 L / min, the disappearance amount of the cleaning liquid is 0.2 L / min, and the pure water mixing amount in the cleaning apparatus 100 is Assuming 0.1 L / min, the cleaning liquid recovered from the cleaning device 100 to the mixing tank 4 has a flow rate (average) of 0.9 (= 1−0.2 + 0.1) L / min and an IPA concentration of 84.4%. Become. At this time, in order to make the concentration of the cleaning liquid 95%, it is necessary to add 1.9 L / min of 99.9% IPA to the recovered cleaning liquid ((84.4 * 0.9 + 99.9X) / Since (0.9 + X) = 95, X = 1.9), and the flow rate after concentration adjustment is 2.8 (= 0.9 + 1.9) L / min, so the amount of liquid in the system increases (increase) Speed 1.8 (= 2.8-1) L / min). Therefore, it is necessary to take measures such as discharging a part of the cleaning liquid whose concentration has been adjusted out of the system, or discarding a part of the recovered cleaning liquid and reducing the amount of recovered liquid (recovery rate). IPA is wasted.

  Even when the IPA concentration of the cleaning liquid to be managed is low, if the amount of pure water mixed in the cleaning apparatus 100 is large (= the cleaning liquid is greatly diluted by the cleaning apparatus), IPA is wasted. For example, when the IPA concentration of the cleaning liquid is controlled to 20%, the supply flow rate (average) to the cleaning apparatus 100 is 1 L / min, the disappearance amount of the cleaning liquid is 0.1 L / min, and the amount of pure water mixed in the cleaning apparatus 100 is Assuming 0.9 L / min, the cleaning liquid recovered from the cleaning apparatus 100 to the mixing tank 4 has a flow rate (average) of 1.8 L / min and an IPA concentration of 10.0%. At this time, in order to make the concentration of the cleaning solution 20%, it is necessary to add 0.2L / min of 99.9% IPA to the recovered cleaning solution ((10 * 1.8 + 99.9X) / (1 .8 + X) = 20, X = 0.2), and the flow rate after concentration adjustment is 2.0 L / min, so the amount of liquid in the system increases (increase rate 1.0 (= 2.0-1). ) L / min). Therefore, in this case as well, it is necessary to take measures such as discharging a part of the cleaning liquid whose concentration has been adjusted out of the system, or discarding part of the recovered cleaning liquid and reducing the amount of recovered liquid (recovery rate). This also wastes IPA.

  In response to such concerns about the prior invention, the present embodiment concentrates the recovered cleaning liquid by providing the concentrator 16 in the liquid recovery path for recovering the cleaning liquid from the cleaning device 100 to the mixing tank 4. Since the cleaning liquid can be circulated, the amount of IPA used for concentration adjustment can be reduced.

  Furthermore, the concentration control in the mixing tank 4 can be stably performed with high accuracy by adjusting the IPA concentration of the concentrate sent from the concentrator 16 to the mixing tank 4 within a certain range (preferably ideal concentration). Can do. In addition, the amount of waste liquid outside the system of the cleaning liquid is reduced.

`` Liquid volume adjustment process ''
Moreover, in this embodiment, the liquid quantity adjustment process which maintains the quantity of the liquid in the mixing tank 4 within a predetermined liquid quantity range may be performed. In this case, a liquid level measuring means (level sensor) (not shown) is provided in the mixing tank 4 and the liquid level (liquid level) of the cleaning liquid in the mixing tank 4 is continuously or intermittently monitored. The control unit 7 executes a liquid amount adjustment process based on the monitoring result of the level sensor. Specifically, the amount of the cleaning liquid in the mixing tank 4 can be circulated between a predetermined liquid amount range (between the mixing tank 4 and the cleaning device 100 by monitoring with a level sensor, and the semiconductor wafer is cleaned in the cleaning tank. When a decrease in excess of the range sufficient for drying) is detected, the valves 15a, 15b are opened, and the IPA and ultrapure water source 3 and the ultrapure water source 3 are transferred to the mixing tank 4. Pure water is supplied at a constant rate. On the other hand, when it is detected by monitoring by the level sensor that the amount of the cleaning liquid in the mixing tank 4 has increased beyond a predetermined liquid amount range, the control unit 7 controls the waste liquid means, A part of the cleaning liquid in the mixing tank 4 is discarded. Specifically, a valve (not shown) on the pipe 13 is opened, and a part of the cleaning liquid in the mixing tank 4 is discarded to the waste liquid tank 6. In this way, a predetermined amount of cleaning liquid having an ideal concentration or a concentration close to this is always held in the mixing tank 4. That is, the control unit 7 in the present embodiment also functions as a second control unit of the invention according to claim 3 of the present application.

  However, while the cleaning liquid circulates as described above, the component concentration of the cleaning liquid changes due to various factors. The most common concentration change is a decrease in IPA concentration, but other concentration changes are possible. Therefore, the concentration adjustment process is performed continuously or intermittently even during the circulation of the cleaning liquid. Specifically, the component concentration of the cleaning liquid is continuously or intermittently measured by the concentration measuring device 5 under the control of the control unit 7 and the component concentration of the cleaning liquid changes beyond a predetermined concentration range. , Both or one of IPA and ultrapure water is replenished to the mixing tank 4. Specifically, according to the measurement result of the concentration measuring device 5, both or one of the valve 15a and the valve 15b is opened, and both or one of the IPA supply source 2 and the ultrapure water supply source 3 are operated. Both or one of IPA and ultrapure water is replenished to the mixing tank 4.

  Here, from the viewpoint of reducing the amount of IPA required for concentration adjustment as much as possible, it is preferable to execute the liquid amount adjustment processing prior to the execution of the concentration adjustment processing. Further, in the liquid amount adjustment process, the amount of the cleaning liquid in the mixing tank 4 is adjusted to an amount that is within a predetermined liquid amount range and does not reach the upper limit of the liquid amount range. IPA and / or pure water are supplied so that the amount of the cleaning liquid in 4 does not exceed the upper limit of the liquid amount range.

  As the concentration measuring device 5, an ultrasonic densitometer, a specific resistance meter, an infrared spectrometer, a Brix meter, a specific gravity meter, or the like can be used. Moreover, as a liquid quantity measurement means, the liquid quantity in the mixing tank 4 may be calculated | required from the load of the mixing tank 4 using a load cell.

  In addition, a pump and a valve are installed on the above-described piping as necessary. Moreover, a filter can also be installed as needed. Furthermore, the temperature of the cleaning liquid may be controlled by installing a heat exchanger on the pipe.

“Treatment of contaminated cleaning fluid”
Furthermore, when the cleaning liquid is contaminated with impurities due to cleaning / drying of the semiconductor wafer, the cleaning liquid may be replaced. However, in this embodiment, a part of the contaminated cleaning liquid is discharged through the pipe 13 as waste liquid. By extracting to the tank 6 and supplying IPA and ultrapure water to the mixing tank 4, the impurities can be diluted to produce a cleaning solution with an ideal concentration. Thereby, the cleaning liquid with the ideal concentration can be supplied to the cleaning apparatus without stopping the cleaning process without replacing all of the contaminated cleaning liquid. The extraction of the cleaning liquid and the dilution of impurities may be performed separately or simultaneously. In order to reduce the amount of IPA and ultrapure water used for diluting the impurities, a part of the cleaning solution is extracted to reduce the volume, and then IPA and ultrapure water are supplied to the mixing tank 4 to dilute the impurities. It is preferable to carry out. When the cleaning liquid is contaminated with impurities and the amount of liquid in the mixing tank 4 is reduced, the IPA and ultrapure water are added to the mixing tank 4 without extracting the contaminated cleaning liquid into the waste liquid tank 6. By supplying, it is possible to dilute impurities and make an ideal concentration cleaning solution. In order to monitor the impurity concentration of the cleaning liquid, for example, a particle detector (particle meter) is provided on the pipes 14a, 14b, 14c or 12 or through these branch lines or a sampling line directly connected to the mixing tank 4. The amount of fine particles (impurities) in the cleaning liquid may be monitored. In addition, when the impurity has a property of absorbing light, the amount of the impurity can be monitored by an absorptiometer.

(Second embodiment)
Hereinafter, the second embodiment of the present invention will be described in detail. FIG. 2 is a block diagram showing a basic configuration of the liquid management system according to the present embodiment.

  The liquid management system 1B shown in FIG. 2 is the liquid management according to the first embodiment except for the connection configuration of the cleaning liquid supply / recovery pipe among the cleaning device 100, the mixing tank 4, and the concentrator 16. The configuration is essentially the same as that of the system 1A. Therefore, about the structure which is common with 1 A of liquid management systems, the same code | symbol is attached | subjected in FIG. 2, and description is abbreviate | omitted.

  In the present embodiment, as shown in FIG. 2, the cleaning device 100 and the concentrator 16 are not communicated with each other, and the cleaning device 100 and the mixing tank 4 are connected to each other via pipes 14 a and 14 e. The pipe 14a constitutes a first liquid feeding means for sending the cleaning liquid whose concentration is adjusted from the mixing tank 4 to the cleaning apparatus 100 as in the first embodiment. The pipe 14 e constitutes a fifth liquid feeding means for sending the cleaning liquid discharged from the cleaning device 100 to the mixing tank 4.

  Furthermore, the mixing tank 4 and the concentrator 16 are connected to each other via pipes 14c and 14f. The pipe 14 c constitutes a third liquid feeding means for sending the cleaning liquid concentrated by the concentrator 16 to the mixing tank 4 as in the first embodiment. The pipe 14 f forms sixth liquid feeding means for sending the cleaning liquid in the mixing tank 4 containing the cleaning liquid discharged from the cleaning apparatus 100 to the concentrator 16. Each liquid feeding means is provided with a pump or the like that causes a liquid flow in a target direction as required.

  In the liquid management system 1B shown in FIG. 2, first, the cleaning liquid whose concentration is controlled in the mixing tank 4 is supplied to the cleaning tank of the cleaning apparatus 100 through the pipe 14a. The cleaning liquid discharged from the cleaning tank of the cleaning apparatus 100 is sent to the mixing tank 4 through the pipe 14e.

  In the cleaning tank, the IPA concentration and the amount of impurities of the cleaning liquid in the cleaning tank differ in the process of cleaning the wafer due to the influence of the cleaning liquid and moisture taken out or brought in as wafer deposits or evaporation. In general, however, the IPA concentration of the cleaning liquid discharged from the cleaning apparatus 100 is reduced as compared with the IPA concentration of the cleaning liquid supplied from the mixing tank 4 to the cleaning apparatus 100 due to mixing of pure water, IPA evaporation, or the like. Therefore, the IPA concentration of the cleaning liquid in the mixing tank 4 tends to decrease. The cleaning liquid in the mixing tank 4 containing the cleaning liquid discharged from the cleaning tank is sent to the concentrator 16 through the pipe 14f to concentrate IPA.

  As the concentration means of the concentrator 16, it is preferable to apply a PV method or a VP method using a membrane made of zeolite, polyimide, or the like, as in the first embodiment.

  The concentrated liquid that has passed through the concentrator 16 is sent to the mixing tank 4 via the pipe 14 c, and the waste liquid from the concentrator 16 is sent to the waste liquid tank 6. In the mixing tank 4, the IPA concentration of the cleaning liquid is adjusted by the IPA supply means and the ultrapure water supply means, and the cleaning liquid whose concentration has been adjusted is sent to the cleaning device 100 again via the pipe 14a. As described above, the cleaning liquid is circulated between the mixing tank 4 and the cleaning device 100 and between the mixing tank 4 and the concentrator 16. Thereby, it is possible to supply the cleaning liquid of the ideal concentration to the cleaning apparatus 100 without stopping the cleaning process.

  In this embodiment, by providing a concentrator 16 for extracting and concentrating the cleaning liquid collected in the mixing tank 4 and returning it to the mixing tank 4, as in the first embodiment, IPA added for concentration adjustment is provided. The amount of use can be reduced. Furthermore, the concentration control in the mixing tank 4 can be stably performed with high accuracy by adjusting the IPA concentration of the concentrate sent from the concentrator 16 to the mixing tank 4 within a certain range (preferably ideal concentration). Can do. In addition, the amount of waste liquid outside the system of the cleaning liquid is reduced.

  In particular, the present embodiment is configured to extract the cleaning liquid in the mixing tank 4 containing the cleaning liquid recovered from the cleaning apparatus 100 and concentrate it in the concentrator 16, and then return it to the mixing tank 4. Applicable when the tolerance can be increased.

  Note that the concentration treatment using the pipes 14c and 14f may be performed regularly or unsteadily. In the case of non-stationary, concentration processing is started when the inside of the mixing tank 4 becomes equal to or lower than the preset IPA concentration, and concentration processing for a certain time is performed, or the IPA concentration of the mixing tank 4 is set separately. Concentration treatment is performed until the above is reached.

  Moreover, in the mixing tank 4, it is preferable to perform the liquid volume adjustment process similar to 1st embodiment, and the process of the contaminated cleaning liquid.

(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described in detail. FIG. 3 is a block diagram showing a basic configuration of the liquid management system according to the present embodiment.

  The liquid management system 1C shown in FIG. 3 includes a purifier that purifies the cleaning liquid discharged from the cleaning device in the liquid management system 1A according to the first embodiment in either one or both of the front and rear stages of the concentrator 16. Except for the points provided, the liquid management system 1A according to the first embodiment has essentially the same configuration. Therefore, about the structure which is common with 1 A of liquid management systems, the same code | symbol is attached | subjected in FIG. 3, and description is abbreviate | omitted.

  In the present embodiment, as shown in FIG. 3, the cleaning device 100 and the purification device 17 are connected to each other via a pipe 14b, and the cleaning liquid discharged from the cleaning apparatus 100 by the second liquid feeding means including the pipe 14b. Is sent to the purifier 17. The purifier 17 is disposed on the liquid introduction side of the concentrator 16. The pipe 14 c constitutes a third liquid feeding means for sending the cleaning liquid concentrated by the concentrator 16 to the mixing tank 4 as in the first embodiment. Each liquid feeding means is provided with a pump or the like that causes a liquid flow in a target direction as required.

  Although FIG. 3 shows a configuration in which the purifier 17 is installed in the front stage of the concentrator 16, the purifier 17 may be provided in the rear stage or both before and after the concentrator 16 as described above. When the purifier 17 is installed at the subsequent stage of the concentrator 16, that is, on the liquid outlet side of the concentrator, the cleaning device 100 and the concentrator 16 are connected by a pipe 14b, and the purifier 17 and the mixing tank 4 are connected by a pipe 14c. Connect with.

  In the liquid management system 1 </ b> C shown in FIG. 3, first, the cleaning liquid whose concentration is adjusted in the mixing tank 4 is supplied to the cleaning tank of the cleaning device 100 through the pipe 14 a. Subsequently, the cleaning liquid discharged from the cleaning tank of the cleaning device 100 is sent to the purification device 17 through the pipe 14b. The cleaning liquid that has passed through the purifier 17 is processed by the concentrator 16.

  In the cleaning tank, the IPA concentration and the amount of impurities of the cleaning liquid in the cleaning tank differ in the process of cleaning the wafer due to the influence of the cleaning liquid and moisture taken out or brought in as wafer deposits or evaporation. In general, however, the IPA concentration of the cleaning liquid discharged from the cleaning apparatus 100 is reduced as compared with the IPA concentration of the cleaning liquid supplied from the mixing tank 4 to the cleaning apparatus 100 due to mixing of pure water, IPA evaporation, or the like. Therefore, IPA is concentrated by the concentrator 16. Further, since the impurity amount of the cleaning liquid increases due to impurities from the cleaning apparatus 100, wafer deposits, piping, etc., the purification apparatus 17 removes impurities from the cleaning liquid discharged from the cleaning apparatus 100.

  As the concentration means of the concentrator 16, it is preferable to apply a PV method or a VP method using a membrane made of zeolite, polyimide, or the like, as in the first embodiment.

  The purifier 17 is appropriately selected depending on the object to be removed. For example, an ion exchange resin tower, an ion adsorption membrane, a filter (microfiltration membrane), a distillation can, an evaporator, and the like can be appropriately used as the purification device 17.

  The concentrated liquid that has passed through the concentrator 16 is sent to the mixing tank 4 via the pipe 14 c, and the waste liquid from the concentrator 16 is sent to the waste liquid tank 6. In the mixing tank 4, the IPA concentration of the cleaning liquid is adjusted by the IPA supply means and the pure water supply means, and the cleaning liquid whose concentration has been adjusted is sent again to the cleaning device 100 via the pipe 14 a. In this way, the cleaning liquid circulates again from the mixing tank 4 to the mixing tank 4 via the cleaning device 100, the purification device 17 and the concentrator 16. Thereby, it is possible to supply the cleaning liquid of the ideal concentration to the cleaning apparatus 100 without stopping the cleaning process.

  In the present embodiment, by using the concentrator 16 in the liquid recovery path for returning the cleaning liquid from the cleaning device 100 to the mixing tank 4, the amount of IPA added for concentration adjustment is the same as in the first embodiment. Can be reduced. Furthermore, the concentration control in the mixing tank 4 can be stably performed with high accuracy by adjusting the IPA concentration of the concentrate sent from the concentrator 16 to the mixing tank 4 within a certain range (preferably ideal concentration). Can do. In addition, the amount of waste liquid outside the system of the cleaning liquid is reduced.

  In particular, in the present embodiment, since the purifier 17 is provided in one or both of the former stage and the latter stage of the concentrator 16 in the first embodiment, a high-purity cleaning liquid is stably supplied to the washing apparatus 100. be able to.

  Moreover, in the mixing tank 4, it is preferable to perform the liquid volume adjustment process similar to 1st embodiment.

(Fourth embodiment)
Hereinafter, the fourth embodiment of the present invention will be described in detail. FIG. 4 is a block diagram showing a basic configuration of the liquid management system according to the present embodiment.

  The liquid management system 1D shown in FIG. 4 is provided with a purifier 17 for purifying a used cleaning liquid in either or both of the front and rear stages of the concentrator 16 in the liquid management system 1B according to the second embodiment. Except for the above, the liquid management system 1B according to the second embodiment has essentially the same configuration. Therefore, about the structure which is common in the liquid management system 1B, the same code | symbol is attached | subjected in FIG. 4, and description is abbreviate | omitted.

  In the present embodiment, as shown in FIG. 4, the mixing tank 4 and the purifier 17 are connected to each other via a pipe 14f, and the cleaning liquid discharged from the cleaning apparatus 100 by the sixth liquid feeding means including the pipe 14f. The cleaning liquid in the mixing tank 4 containing is sent to the purification device 17. The purifier 17 is disposed on the liquid introduction side of the concentrator 16. The pipe 14 c constitutes a third liquid feeding means for sending the cleaning liquid concentrated by the concentrator 16 to the mixing tank 4 as in the second embodiment. Each liquid feeding means is provided with a pump or the like that causes a liquid flow in a target direction as required.

  Although FIG. 4 shows a configuration in which the purifier 17 is installed before the concentrator 16, as described above, the purifier 17 may be provided after the concentrator 16 or both before and after. When the purifier 17 is installed at the subsequent stage of the concentrator 16, that is, on the liquid outlet side of the concentrator, the mixing tank 4 and the concentrator 16 are connected by a pipe 14f, and the purifying apparatus 17 and the mixing tank 4 are connected by a pipe 14c. Connect with.

  In the liquid management system 1D shown in FIG. 4, first, the cleaning liquid whose concentration is controlled in the mixing tank 4 is supplied to the cleaning tank of the cleaning apparatus 100 via the pipe 14a. The cleaning liquid discharged from the cleaning tank of the cleaning apparatus 100 is sent to the mixing tank 4 through the pipe 14e. Thereby, the cleaning liquid discharged from the cleaning apparatus 100 is partially included in the cleaning liquid in the mixing tank 4.

  In the cleaning tank, the IPA concentration and the amount of impurities of the cleaning liquid in the cleaning tank differ in the process of cleaning the wafer due to the influence of the cleaning liquid and moisture taken out or brought in as wafer deposits or evaporation. In general, however, the IPA concentration of the cleaning liquid discharged from the cleaning apparatus 100 is reduced as compared with the IPA concentration of the cleaning liquid supplied from the mixing tank 4 to the cleaning apparatus 100 due to mixing of pure water, IPA evaporation, or the like. In addition, the amount of impurities in the cleaning liquid increases due to impurities from the cleaning apparatus 100, wafer deposits, piping, and the like. Therefore, the IPA concentration in the mixing tank 4 decreases and the amount of impurities tends to increase.

  Therefore, the cleaning liquid in the mixing tank 4 is sent to the purification device 17 through the pipe 14f, and the purification device 17 removes impurities from the cleaning liquid. Further, the cleaning liquid purified by the purifier 17 is sent to the concentrator 16 to concentrate IPA.

  As the concentration means of the concentrator 16, it is preferable to apply a PV method or a VP method using a membrane made of zeolite, polyimide, or the like, as in the first embodiment.

  The purifier 17 is appropriately selected depending on the object to be removed. For example, an ion exchange resin tower, an ion adsorption membrane, a filter (microfiltration membrane), a distillation can, an evaporator, and the like can be appropriately used as the purification device 17.

  The concentrated liquid that has passed through the concentrator 16 is sent to the mixing tank 4 via the pipe 14 c, and the waste liquid from the concentrator 16 is sent to the waste liquid tank 6. In the mixing tank 4, the IPA concentration of the cleaning liquid is adjusted by the IPA supply means and the pure water supply means, and the cleaning liquid whose concentration has been adjusted is sent again to the cleaning device 100 via the pipe 14 a. As described above, the cleaning liquid is circulated between the mixing tank 4 and the cleaning apparatus 100 and between the mixing tank 4, the purification apparatus 17, and the concentrator 16. Thereby, it is possible to supply the cleaning liquid of the ideal concentration to the cleaning apparatus 100 without stopping the cleaning process.

  In this embodiment, by providing a concentrator 16 for extracting and concentrating the cleaning liquid collected in the mixing tank 4 and returning it to the mixing tank 4, as in the first embodiment, IPA added for concentration adjustment is provided. The amount of use can be reduced. Furthermore, the concentration control in the mixing tank 4 can be stably performed with high accuracy by adjusting the IPA concentration of the concentrate sent from the concentrator 16 to the mixing tank 4 within a certain range (preferably ideal concentration). Can do. In addition, the amount of waste liquid outside the system of the cleaning liquid is reduced.

  In particular, in the present embodiment, since the purifier 17 is provided in one or both of the former stage and the latter stage of the concentrator 16 in the second embodiment, a high-purity cleaning liquid is stably supplied to the cleaning apparatus 100. be able to.

  Note that the concentration treatment using the pipes 14c and 14f may be performed regularly or unsteadily. In the case of non-stationary, concentration processing is started when the inside of the mixing tank 4 becomes equal to or lower than the preset IPA concentration, and concentration processing for a certain time is performed, or the IPA concentration of the mixing tank 4 is set separately. Concentration treatment is performed until the above is reached.

  Moreover, in the mixing tank 4, it is preferable to perform the liquid volume adjustment process similar to 1st embodiment.

  Further, as described in the second embodiment, this embodiment is suitable when the allowable value of the IPA concentration range of the mixing tank 4 can be increased.

(Fifth embodiment)
Hereinafter, a fifth embodiment of the present invention will be described in detail. FIG. 5 is a block diagram showing a basic configuration of the liquid management system according to the present embodiment.

  The liquid management system 1E shown in FIG. 5 is the same as the liquid management system 1A according to the first embodiment except that a purification device for purifying the cleaning liquid is provided in the liquid supply path between the mixing tank 4 and the cleaning device 100. The liquid management system 1A according to the first embodiment has essentially the same configuration. Therefore, about the structure which is common with 1 A of liquid management systems, the same code | symbol is attached | subjected in FIG. 5, and description is abbreviate | omitted.

  In this embodiment, as shown in FIG. 5, the mixing tank 4 and the refiner 17 are connected to each other via a pipe 14a, and the concentration is adjusted from the mixing tank 4 by the first liquid feeding means including the pipe 14a. The cleaning liquid is sent to the purification device 17. Further, the purifying device 17 and the cleaning device 100 are connected to each other via the pipe 14g, and the cleaning liquid purified by the purifying device 17 is sent to the cleaning device 100 by the seventh liquid feeding means including the pipe 14g. Each liquid feeding means is provided with a pump or the like that causes a liquid flow in a target direction as required.

  In the liquid management system 1E shown in FIG. 5, first, the cleaning liquid whose concentration is adjusted in the mixing tank 4 is sent to the purifier 17 via the pipe 14a. Subsequently, the cleaning liquid purified by the purification device 17 is supplied to the cleaning tank of the cleaning device 100 through the pipe 14g.

  In the cleaning tank, the IPA concentration and the amount of impurities of the cleaning liquid in the cleaning tank differ in the process of cleaning the wafer due to the influence of the cleaning liquid and moisture taken out or brought in as wafer deposits or evaporation. In general, however, the IPA concentration of the cleaning liquid discharged from the cleaning apparatus 100 is reduced as compared with the IPA concentration of the cleaning liquid supplied from the mixing tank 4 to the cleaning apparatus 100 due to mixing of pure water, IPA evaporation, or the like. Therefore, the cleaning liquid discharged from the cleaning apparatus 100 is sent to the concentrator 16 to concentrate IPA.

  As the concentration means of the concentrator 16, it is preferable to apply a PV method or a VP method using a membrane made of zeolite, polyimide, or the like, as in the first embodiment.

  The purifier 17 is appropriately selected depending on the object to be removed. For example, an ion exchange resin tower, an ion adsorption membrane, a filter (microfiltration membrane), a distillation can, an evaporator, and the like can be appropriately used as the purification device 17. In addition, when using a distillation can or an evaporation can, care must be taken because the IPA concentration before and after purification may change depending on the use conditions.

  The concentrated liquid that has passed through the concentrator 16 is sent to the mixing tank 4 via the pipe 14 c, and the waste liquid from the concentrator 16 is sent to the waste liquid tank 6. In the mixing tank 4, the IPA concentration of the cleaning liquid is adjusted by the IPA supply means and the pure water supply means, and the cleaning liquid whose concentration is adjusted is sent again to the cleaning apparatus 100 through the pipe 14a, the purification apparatus 17, and the pipe 14g in order. Although the impurity amount of the cleaning liquid returned to the mixing tank 4 increases due to impurities from the cleaning apparatus 100, wafer deposits, piping, etc., the purification apparatus 17 can remove the impurities of the cleaning liquid.

  In this way, the cleaning liquid is circulated from the mixing tank 4 to the mixing tank 4 again through the purification device 17, the cleaning device 100 and the concentrator 16 in this order. Thereby, it is possible to supply the cleaning liquid of the ideal concentration to the cleaning apparatus 100 without stopping the cleaning process.

  In the present embodiment, by using the concentrator 16 in the liquid recovery path for returning the cleaning liquid from the cleaning device 100 to the mixing tank 4, the amount of IPA added for concentration adjustment is the same as in the first embodiment. Can be reduced. Furthermore, the concentration control in the mixing tank 4 can be stably performed with high accuracy by adjusting the IPA concentration of the concentrate sent from the concentrator 16 to the mixing tank 4 within a certain range (preferably ideal concentration). Can do. In addition, the amount of waste liquid outside the system of the cleaning liquid is reduced.

  In particular, in the present embodiment, since the refining device 17 is provided in the liquid supply path between the mixing tank 4 and the cleaning device 100 as compared with the first embodiment, a high-purity cleaning liquid is stably supplied to the cleaning device 100. be able to.

  Moreover, in the mixing tank 4, it is preferable to perform the liquid volume adjustment process similar to 1st embodiment.

  In addition, the position where the concentrator 16 and the purification device 17 are installed is not limited to the place shown in FIGS. The concentrator 16 should just be provided in the line which collect | recovers the washing | cleaning liquid discharged | emitted from the washing | cleaning apparatus 100, and returns it to the mixing tank 4. FIG. On the other hand, the purification device 17 may be provided in the line or a line for supplying the cleaning liquid whose concentration is adjusted to the cleaning device 100. Further, the order in which the liquid passes through the concentrating device 16 and the purifying device 17 is not particularly limited. Therefore, a processing configuration such as concentration after purification, purification after concentration, concentration after purification, and purification again may be employed.

Example 1
Next, Example 1 of the present invention will be described. This example is a more specific example of the first and second embodiments described above.

  A 6-inch silicon wafer was set in the cleaning tank of the single wafer spin cleaning apparatus, and a cleaning liquid in which IPA and pure water were mixed to obtain an IPA concentration of 95% and pure water were alternately supplied to the cleaning tank. The silicon wafer to be cleaned is left for 1 week in a clean room.

  The flow rate of the pure water to the cleaning tank was 2 L / min, the flow rate of the cleaning liquid having the above IPA concentration to the cleaning tank was 1 L / min, and the supply time for both was 1 minute.

  The washing tank is provided with a drain line, and the cleaning liquid discharged from the drain line is collected during the cleaning liquid supply, and the liquid discharged from the drain line during the pure water supply is It was discharged out of the system without being collected.

  The alternate supply of the cleaning liquid and pure water to the cleaning tank was repeated 15 times, and 10 L of the discharged cleaning liquid was collected. The IPA concentration of the recovered liquid was 85%. In order to make the recovered liquid have a management concentration of 95% for the cleaning liquid, it is necessary to add 20 L of the new IPA liquid (99.9%). At this time, the liquid volume is at least 30 L. This liquid amount is larger than the supplied cleaning liquid amount 15 (= 1 × 15) L, and the cleaning liquid (IPA) is wasted because the amount of the cleaning liquid in the system increases.

  Therefore, the recovered liquid was concentrated using a zeolite membrane VP (Vapor Permeation) apparatus to obtain a processing liquid having an IPA concentration of 99.9%. Since water is removed from the recovered liquid by the concentration process and the entire recovered liquid volume is reduced, the amount of IPA added to the recovered liquid can be reduced, and as a result, wasteful use of IPA can be prevented. Even if the IPA concentration of the treatment liquid is less than the IPA concentration of the cleaning liquid, this effect can be exhibited.

  Further, if the concentrator is designed and adjusted so that the IPA concentration of the treatment liquid is close to the IPA concentration of the cleaning liquid, the concentration adjustment in the mixing tank can be performed stably and accurately.

(Example 2)
Next, a second embodiment of the present invention will be described. This example is a more specific example of the third and fourth embodiments described above.

  A 6-inch silicon wafer was set in the cleaning tank of the single wafer spin cleaning apparatus, and a cleaning liquid in which IPA and pure water were mixed to obtain an IPA concentration of 95% and pure water were alternately supplied to the cleaning tank. The silicon wafer to be cleaned is left for 1 week in a clean room.

  The flow rate of the pure water to the cleaning tank was 2 L / min, the flow rate of the cleaning liquid having the above IPA concentration to the cleaning tank was 1 L / min, and the supply time for both was 1 minute.

  The washing tank is provided with a drain line, and the cleaning liquid discharged from the drain line is collected during the cleaning liquid supply, and the liquid discharged from the drain line during the pure water supply is It was discharged out of the system without being collected.

  The alternate supply of the cleaning liquid and pure water to the cleaning tank was repeated 15 times, and 10 L of the discharged cleaning liquid was collected.

  At this time, the metal concentration in the cleaning solution and the recovered solution was measured with an ICP mass spectrometer (ICP-MS). The measurement results are shown in Table 1. Due to impurities from the cleaning apparatus and the wafer, the metal concentration of the recovered liquid was higher than the metal concentration of the supplied cleaning liquid. Therefore, this recovered liquid was purified by an ion exchange resin tower (mixed bed type in which an anion resin and a cation resin were packed in one tower). Table 1 shows the metal concentration of the recovered liquid after purification. From this table, it can be seen that purification can be performed to a metal concentration equivalent to that of the cleaning liquid at the time of supply.

   The IPA concentration of the recovered liquid was 85%. However, there was no change in the IPA concentration before and after purification. In order to make the recovered liquid have a management concentration of 95% for the cleaning liquid, it is necessary to add 20 L of the new IPA liquid (99.9%). At this time, the liquid volume is at least 30 L. This liquid amount is larger than the supplied cleaning liquid amount 15 (= 1 × 15) L, and the cleaning liquid (IPA) is wasted because the amount of the cleaning liquid in the system increases.

  Therefore, the purified recovered solution was concentrated using a zeolite membrane VP (Vapor Permeation) apparatus to obtain a processing solution having an IPA concentration of 99.9%. Since water is removed from the recovered liquid by the concentration process and the entire recovered liquid volume is reduced, the amount of IPA added to the recovered liquid can be reduced, and as a result, wasteful use of IPA can be prevented. This effect can be exhibited even when the IPA concentration of the concentrated treatment liquid is less than the IPA concentration of the cleaning liquid.

  Further, if the concentrator is designed and adjusted so that the IPA concentration of the treatment liquid is close to the IPA concentration of the cleaning liquid, the concentration adjustment in the mixing tank can be performed stably and accurately.

(Example 3)
Next, a third embodiment of the present invention will be described. This example is a more specific example of the third and fourth embodiments described above. However, although Example 2 was an example which performs a concentration process after purification, this example is an example in which a purification process is performed after concentration.

  The same experiment as in Example 2 was performed, and the IPA concentration of the recovered liquid at this time was measured and found to be 85%. In order to make the recovered liquid have a management concentration of 95% for the cleaning liquid, it is necessary to add 20 L of the new IPA liquid (99.9%). At this time, the liquid volume is at least 30 L. This liquid amount is larger than the supplied cleaning liquid amount 15 (= 1 × 15) L, and the cleaning liquid (IPA) is wasted because the amount of the cleaning liquid in the system increases.

  Therefore, the recovered liquid was concentrated by a VP (Vapor Permeation) apparatus using a zeolite membrane to obtain a processing liquid having an IPA concentration of 99.9%. Since water is removed from the recovered liquid by the concentration process and the entire recovered liquid volume is reduced, the amount of IPA added to the recovered liquid can be reduced, and as a result, wasteful use of IPA can be prevented. This effect can be exhibited even when the IPA concentration of the concentrated treatment liquid is less than the IPA concentration of the cleaning liquid. Moreover, if the concentrator is designed and adjusted so that the IPA concentration of the concentrated treatment liquid is close to the IPA concentration of the cleaning liquid, the concentration adjustment in the mixing tank can be performed stably and accurately.

  Moreover, the metal concentration in the cleaning liquid at the time of supply and the concentration treatment liquid was measured with an ICP mass spectrometer (ICP-MS). The measurement results are shown in Table 2. Due to impurities from the cleaning apparatus, wafer, etc., the metal concentration of the concentrated treatment liquid was higher than the metal concentration of the supplied cleaning liquid. Therefore, the concentrated treatment liquid was purified by an ion exchange resin tower (mixed bed type in which an anion resin and a cation resin were packed in one tower). Table 2 shows the metal concentration of the treated liquid after purification. From this table, it can be seen that purification can be performed to a metal concentration equivalent to that of the cleaning liquid at the time of supply.

1A, 1B, 1C, 1D, 1E Liquid management system 2 IPA supply source 3 Ultrapure water supply source 4 Mixing tank 5 Concentration measuring device 6 Waste liquid tank 7 Control unit 10, 11, 12, 13, 14a-14g Piping 15a, 15b Valve 16 Concentrator 100 Cleaning device

Claims (3)

A liquid management system for managing a cleaning liquid used in a cleaning apparatus for cleaning an object,
Mixing means for mixing alcohol and pure water to make a cleaning solution;
A concentration adjusting means for adjusting the alcohol concentration in the cleaning liquid within a predetermined concentration range by the mixing means;
A line that collects the cleaning liquid discharged from the cleaning device and returns it to the mixing means, and constitutes a circulation line for circulating the cleaning liquid between the mixing means and the cleaning device ;
A concentrator which is provided on a line returning to the mixing means and concentrates alcohol in the cleaning liquid discharged from the cleaning device,
The density adjusting means includes
Alcohol supply means for supplying alcohol to the mixing means;
Pure water supply means for supplying pure water to the mixing means;
Concentration measuring means for measuring the alcohol concentration of the cleaning liquid in the mixing means;
The cleaning liquid in the mixing means during the circulation of the cleaning liquid along the line returning to the mixing means by controlling both or one of the alcohol supply means and the pure water supply means based on the measurement result of the concentration measuring means And a first control means for executing a concentration adjustment process for maintaining the alcohol concentration within a predetermined concentration range,
Liquid management system.
The concentrator is one that utilizes a membrane concentration by PV method or VP method, fluid management system of claim 1. A liquid amount measuring means for measuring the amount of cleaning liquid obtained by mixing alcohol and pure water by the mixing means;
By controlling the alcohol supply unit and the pure water supply unit based on the measurement result of the liquid amount measurement unit, the amount of the cleaning liquid obtained by mixing alcohol and pure water by the mixing unit is maintained within a predetermined liquid amount range. Second control means for performing a liquid amount adjustment process to be performed;
Further comprising a liquid management system according to claim 1 or 2.

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