KR20180126454A - And apparatus for producing and supplying sulfuric acid solution - Google Patents

Abstract

There is provided an apparatus and a method for producing and supplying a persulfate solution in which the replacement time of the persulfate solution in the semiconductor wafer cleaner is shortened. Water and sulfuric acid are introduced into the storage tank 41 of the second electrolytic system while the first electrolytic system 20 circulates and supplies the persulfuric acid solution to the cleaning tank 11 and the pump 44, 45, the electrolytic cell 50, the gas-liquid separator 52, and the pipe 53 to produce persulfuric acid. In the chemical change, after draining from the first electrolytic system 20, the persulfuric acid solution in the storage tank 41 is transferred to the storage tank 22.

Description

And apparatus for producing and supplying sulfuric acid solution

The present invention relates to an apparatus and a method for supplying a sulfuric acid solution to a cleaning apparatus or the like for cleaning a semiconductor wafer.

When the semiconductor wafer is cleaned with the electrolytic sulfuric acid solution, it is necessary to electrolyze the sulfuric acid with at least the electrolytic cell provided with the diamond electrode on the anode, to contain a predetermined amount of persulfuric acid (collectively referred to as peroxoyl sulfuric acid and peroxo sulfuric acid) And an electrolytic sulfuric acid composed of a persulfate solution containing no persulfate is generated, and the electrolytic sulfuric acid is sent to the scrubber. The solution is used to dissolve or clean the resist or metal on the semiconductor wafer.

It takes a long time until electrolysis of sulfuric acid to generate a predetermined amount of persulfuric acid. Therefore, in order to generate and supply electrolytic sulfuric acid as a cleaning liquid in accordance with the cleaning process of the wafer, it is necessary to provide a large number of electrolytic cells.

In Embodiment 5 of Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2008-111184), three electrolytic solution storage tanks are formed, one for discharge to the cleaning section, one for recovery from the cleaning section, After the first turn is completed, it is divided into two groups: one for circulation, one for discharge, one for discharge, one for recovery, and one for circulation. A system for producing electrolytic sulfuric acid in the background during cleaning is described. However, since the electrolysis time is longer than the cleaning time, there is a problem that waiting time until electrolytic sulfuric acid production occurs.

In electrolytic sulfuric acid, sulfuric acid concentration is not lowered with sulfuric acid regeneration such as SPM (sulfuric acid + hydrogen peroxide), so that the cleaning liquid can be circulated, regenerated, and reused for cleaning easily. Therefore, the above-mentioned Patent Document 1 adopts this method. However, since the number of circulation times of the impurities contained in the washing and draining solution (in addition to the trace metals eluted from the wafer, in the case of removal of the resist, the SS from the organic material or the organic material and the residue of the residual metal in the case of removing the residue metal solution) And then mixed and accumulated in the liquid. Therefore, there is a risk that the electrolytic treatment or the cleaning treatment may be adversely affected economically.

Therefore, it is especially necessary to replace the cleaning liquid with the cleaning liquid that has been periodically flushed with the cleaning liquid, especially in the circulation type. Specifically, it is necessary to extract a part of the liquid in the system periodically, periodically or continuously, replenish enough sulfuric acid, and generate electrolytic sulfuric acid to restart the wafer cleaning. However, in the above-mentioned prior art, solution replacement is not considered.

In the Merry-Go-round system such as Japanese Laid-Open Patent Publication No. 2008-111184, all the storage tanks must be made equal in size. For this reason, the system becomes large-scale, for example, 100 liters of the first storage tank, 100 liters of the second storage tank, 100 liters of the third storage tank, 60 liters of the washing tank capacity, and 10 liters of the piping capacity.

As described above, in the case of circulating and reusing the cleaning drainage in the semiconductor wafer cleaning by electrolytic sulfuric acid, the solution is replaced in consideration of the accumulation of impurities contained in the cleaning drainage over time, but the sulfuric acid is electrolyzed, It is not possible to treat the wafer until electrolysis and a predetermined amount of persulfuric acid is produced.

Japanese Patent Application Laid-Open No. 2008-111184

An object of the present invention is to provide an apparatus and method for manufacturing and supplying a persulfuric acid solution in which the replacement time of the persulfuric acid solution in the semiconductor wafer cleaning apparatus is shortened.

The persulfuric acid solution production and supply apparatus of the present invention has a first electrolysis system for circulating and supplying a persulfuric acid solution to a wafer cleaning apparatus. The persulfuric acid solution production and supply device comprises a second electrolysis system for producing a persulfuric acid solution formed separately from the first electrolysis system and a second electrolysis system for producing a persulfuric acid solution for transferring the electrolytic solution from the second electrolysis system to the first electrolysis system. Respectively.

The persulfuric acid solution manufacturing and supplying method of the present invention supplies the persulfuric acid solution to the wafer cleaning apparatus using the persulfuric acid solution producing and supplying apparatus of the present invention. In this method, in at least a part of the step of cleaning the wafer with the wafer cleaning apparatus, an electrolytic treatment is performed on the second electrolytic system to produce a persulfuric acid solution, and the persulfuric acid solution replacement in the wafer cleaning apparatus and the first electrolytic system , The persulfate solution is transferred from the second electrolysis system to the second electrolysis system after discharging the persulfate solution from the wafer cleaning apparatus and the first electrolysis system.

In one embodiment of the present invention, the first electrolytic system includes: a first storage vessel for storing a persulfuric acid solution circulated to the wafer cleaning apparatus; and a second storage vessel for electrolytically treating the liquid supplied from the first storage vessel, And the first electrolytic cell is returned to the first storage tank. The second electrolytic system includes a second storage tank, electrolytic treatment of the liquid supplied from the second storage tank, and electrolytic treatment of the liquid to the second storage tank A second electrolytic cell to be rotated, and a device for supplying sulfuric acid and water to the second storage tank.

In the present invention, in a persulfuric acid solution production and supply apparatus having a first electrolysis system for supplying and transporting electrolytic sulfuric acid to a semiconductor wafer cleaning apparatus, a second electrolytic system is prepared in which electrolytic sulfuric acid is prepared in advance and stored in a reserve tank .

In the apparatus and method of the present invention, electrolytic sulfuric acid can be generated and stored in the second electrolytic system during wafer cleaning, so that the waiting time for cleaning the wafer (chemical change time) can be shortened. There is no fear of contamination or accumulation of impurities in the second electrolytic system because there is no liquid inflow from the first electrolytic system to the second electrolytic system.

1 is a block diagram showing an embodiment.
2 is a flow chart of the apparatus for producing and supplying the persulfuric acid solution of FIG.
3 is a block diagram showing another embodiment.
4 is a flow chart of the apparatus for producing and supplying the persulfuric acid solution of FIG.

The apparatus for producing and supplying a persulfuric acid solution according to a first embodiment of the present invention will be described with reference to Fig.

This persulfuric acid solution production and supply apparatus has a batch type washer 10 for collecting and cleaning a plurality of semiconductor wafers 100 and a first electrolysis system 20 and a second electrolysis system 40. Each of the electrolytic cells 30 and 50 of each electrolytic system 20 and 40 has a power supply device (not shown) that has at least an anode having the anode as a diamond electrode and energizes the anode and the cathode. The electrode may be provided with a bipolar electrode.

The batch type washer 10 includes a cleaning bath 11 in which the electrolytic sulfuric acid solution is filled and a high temperature rinse bath in which the semiconductor wafer 100 after cleaning in the cleaning bath 11 is rinsed and a rinse bath in a high temperature rinse bath A normal-temperature rinsing bath for rinsing the semiconductor wafer 100, and a dryer for drying the semiconductor wafer 100 after rinsing in a room-temperature rinsing bath (all not shown).

The liquid outlet portion and the liquid inlet portion of the cleaning tank 11 are connected by a circulation line composed of a pipe 12, a pump 13, a pipe 14, a heater 15 and a pipe 16. Each piping and device is made of a material having heat resistance against a temperature of 100 ° C or higher, and is made of a fluorine resin such as PFA, for example.

The pipe 17 having the valve 18 is branched from the pipe 16 so that the liquid in the system can be discharged to the outside of the system.

The first electrolytic system 20 includes a storage tank (first storage tank) 22 into which a cleaner discharge liquid is introduced through a piping 21 branched from a pipe 12 and an electrolytic treatment means for electrolyzing the liquid in the storage tank 22 A pump 24, a pipe 25, and the like for transporting electrolytically-treated liquid to the electrolytic cell 30 or the like to the pipe 16.

The liquid in the storage tank 22 is introduced into the electrolytic cell 30 (first electrolytic cell) through the pump 27 and the pipe 28. The electrolytically treated liquid is returned to the storage tank 22 through the pipe 31, the gas-liquid separator 32, and the pipe 33. The gas separated by the gas-liquid separator 32 is sent to the gas processing unit 56.

The second electrolytic system 40 includes a storage tank (second storage tank) 41 in which sulfuric acid and water are respectively supplied from piping 42 and 43 and a liquid in the storage tank 41 as electrolytic cells (second electrolytic cells) Liquid separator 52 in which the liquid electrolytically introduced by the electrolytic cell 50 is introduced through the pipe 51 and the gas (liquid) A pipe 53 for returning the liquid from the separator 52 to the storage tank 41 and a pipe 54 for sending the gas separated by the gas-liquid separator 52 to the gas processing device 56.

The pipe 47 is branched from the pipe 45 and the liquid in the storage tank 41 is supplied to the storage tank 22 of the first electrolytic system through the pipes 45 and 47, the valve 48 and the pipe 49 As shown in Fig.

Next, the operation of the apparatus for producing and supplying the persulfate solution will be described with reference to FIG.

The cleaning tank 11 is filled with a sulfuric acid solution having a sulfuric acid concentration of 70 to 96 mass%. A part of the liquid flowing out from the cleaning tank 11 to the pipe 12 is circulated through the pump 13, the pipe 14, the heater 15 and the pipe 16. For example, the sulfuric acid solution is circulated at a circulating flow rate of 1/2 to 1/3 V / min with respect to the tank volume V of the cleaning tank 11. At this time, the valve 18 is closed.

The remaining portion of the liquid flowing out to the pipe 12 is introduced into the storage tank 22 through the pipe 21. A part of the liquid introduced into the storage tank 22 is supplied to the storage tank 22 through the pump 27, the pipe 28, the electrolytic cell 30, the pipe 31, the gas-liquid separator 32 and the pipe 33 Circulated, and electrolytically treated to produce persulfuric acid. The liquid in the storage tank 22 containing sulfuric acid is supplied to the pipe 16 through the pipe 23, the pump 24 and the pipe 25.

As described above, water and sulfuric acid are introduced into the storage tank 41 of the second electrolytic system during the wafer cleaning, particularly at least at the beginning of the wafer cleaning process, and a part of the liquid in the storage tank 41 is supplied to the pump 44 ), The pipe 45, the electrolytic cell 50, the gas-liquid separator 52, and the pipe 53, and electrolytically treated to produce persulfuric acid. At this time, the valve 46 is opened and the valve 48 is closed. When the concentration of persulfuric acid in the storage tank 41 reaches a predetermined concentration, this circulation is stopped and the persulfuric acid solution is stored in the storage tank 41.

After cleaning the wafer for a predetermined time or a predetermined number of times, the valve 18 is opened and the cleaning tank 11 and the pipes 12, 14, 16, 21, 23, 25 and the first electrolytic system 20 ) Is discharged to the outside of the system through the piping (17).

Subsequently, after the valve 18 is closed, a fresh persulfate solution stored in the storage tank 41 is introduced into the storage tank 22 through the pump 44 and the pipes 45, 47, and 49. At this time, the valve 46 is closed and the valve 48 is opened.

After the predetermined amount of persulfuric acid solution is transferred to the storage tank 22, the transfer is stopped and the liquid in the tank 22 is supplied to the cleaning tank 11 through the pump 24 and the pipes 23 and 25, After the cleaning tank 11 and the circulation lines of the pipes 12, 14, 16 are filled with the persulfate solution, the wafer cleaning is resumed.

2, since the persulfuric acid solution is produced in the second electrolytic system 40 while the wafer 100 is being cleaned in the cleaning tank 11, The liquid is discharged from the cleaning tank 11 and the first electrolytic system 20 and discharged from the second electrolytic system 40 to the cleaning tank 11 and the first electrolytic system 20 between the wafer cleaning of the batch, Only the transfer of the solution can be started to start the cleaning of the next batch, and the time of the persulfate solution renewal operation (chemical change) between the batches is remarkably shortened.

In the present invention, the capacity of the storage tank 22 of the first electrolytic system 20 can be reduced. In the case where the second electrolytic system 40 is not formed, for example, when the washing tank capacity is 60 L and the persulfuric acid solution required for one batch is 100 L, the storage tank 22 capacity is 100 L, the washing tank capacity is 60 L, The capacity of the storage tank 41 is 100 L, the capacity of the storage tank 22 is 30 L, the capacity of the washing tank 60 L and the capacity of the piping 10 L is sufficient when the second electrolytic system 40 is installed , The capacity of the first electrolytic system storage tank 22 is reduced by half, so that the enlargement of the apparatus due to the extension of the second electrolytic system 40 can be suppressed.

Typically, the capacity of the storage tank 22 of the first electrolytic system 20 is about 10 to 80 L and the capacity of the storage tank 41 of the second electrolytic system 40 is about 80 to 150 L.

1 and 2 are batch type cleaning devices, the present invention is also applicable to the single wafer cleaning devices 60 of Figs.

The single wafer cleaning apparatus 60 includes a cleaning liquid nozzle 61 facing the loaded wafer 100 and a rotation table 62 for mounting and rotating the wafer 100. In the cleaning liquid nozzle 61, a sulfuric acid solution as a cleaning liquid is sprayed or flows in a small amount, and is supplied to the upper surface of the wafer 100 held on the rotating table.

The cleaning liquid supplied to the upper surface of the wafer 100 receives the centrifugal force due to the rotation of the wafer 100 and diffuses from the upper surface of the wafer 100 toward the peripheral edge to clean the wafer 100. The cleaning liquid is scattered from the peripheral edge of the wafer 100 and is laterally scattered and introduced into the recovery tank 63 and introduced into the storage tank 66 through the pump 64 and the pipe 65. The liquid in the storage tank 66 is introduced into the storage tank 70 through the pump 67, the heat exchanger 68 and the pipe 69. The liquid in the storage tank 70 is supplied to the cleaning liquid nozzle 61 through the pump 71, the rapid heater 72, the pipe 73, the valve 74 and the pipe 75. A piping (bypass line) 76 is branched from the piping 73 and a valve 77 is formed in the piping 76. When the wafer is cleaned by the cleaning device 60, the valve 74 is opened and the valve 77 is closed. When the wafer cleaning by the cleaning device 60 is stopped, the valve 74 is closed, the valve 77 is opened, and the liquid from the pipe 73 is supplied to the storage tank 66 through the pipe 76 Supply. The rapid heater 72 rapidly heats the sulfuric acid solution to 120 to 220 占 폚, for example, by a near-infrared heater.

The first electrolysis system 80 has the storage tank 70 and the electrolytic cell 30 for electrolytic treatment of the liquid in the storage tank 70 and the like. The configuration of the circulation supply mechanism of the liquid to the electrolytic cell 30 and the electrolytic cell 30 is the same as in the case of Figs. That is, the liquid in the storage tank 70 is introduced into the electrolytic cell 30 through the pump 27 and the piping 28. The electrolytically treated liquid is returned to the storage tank 70 through the pipe 31, the gas-liquid separator 32, and the pipe 33. The gas separated by the gas-liquid separator 32 is sent to the gas processing unit 56.

The configuration of the second electrolytic system 40 is the same as that of Figs. 1 and 2, and the same reference numerals are given to the same members, and a description thereof is omitted.

In this single wafer cleaning apparatus, as shown in Fig. 4, water is supplied to the storage tank 41 of the second electrolytic system during the wafer cleaning by the cleaning apparatus 60, particularly at least at the beginning of the wafer cleaning process, And a part of the liquid in the storage tank 41 is circulated through the pump 44, the pipe 45, the electrolytic cell 50, the gas-liquid separator 52 and the pipe 53, Sulfuric acid is produced. At this time, the valve 46 is opened and the valve 48 is closed. When the concentration of persulfuric acid in the storage tank 41 reaches a predetermined concentration, this circulation is stopped and the persulfuric acid solution is stored in the storage tank 41.

The cleaning apparatus 60, the recovery tank 63, the storage tank 66 and the pipes 65, 69, 73 and 75 and the first electrolytic system 20 (Not shown) connected to the recovery tank 63 or its upstream side.

The fresh persulfate solution stored in the storage tank 41 is then introduced into the storage tank 70 through the pump 44 and the pipes 47 and 49. At this time, the valve 46 is closed and the valve 48 is opened.

After the predetermined amount of persulfuric acid solution is transferred to the storage tank 70, the transfer is stopped and the liquid in the storage tank 70 is supplied to the cleaning device 60 through the pump 71 and the pipes 73 and 75, Wafer cleaning is resumed.

Since the persulfuric acid solution is produced in the second electrolytic system 40 while the wafer 100 is being cleaned by the cleaning device 60 as described above, when the persulfuric acid solution renewal operation is performed, Only the drainage discharge from the second electrolytic system 80 and the transfer of the persulfuric acid solution from the second electrolytic system 40 to them are performed, and the time for the persulfate solution renewal operation (chemical change) is remarkably shortened.

The present invention can be preferably used particularly when the concentration of the oxidizing agent in the persulfate solution is high (for example, 0.03 to 0.1 mol / l) or when the temperature of the cleaning liquid is high (for example, 150 to 180 ° C).

Example

Examples and Comparative Examples of the present invention are shown below.

[Comparative Example 1]

In Fig. 1, the second electrolytic system 40 is omitted. Four electrolytic cells 30 were provided in the first electrolytic system 20. A chemical change was carried out using this apparatus. The existing solution was drained from the pipe 17, and sulfuric acid and water were newly added to the washing tank 11 and the storage tank 22 so that the sulfuric acid concentration was 85%. The solution temperature in the cleaning tank 11 was set at 120 占 폚. Thereafter, the electrolytic cell 30 was energized at a current density of 0.4 A / cm 2 to generate an electrolytic sulfuric acid solution, and the oxidant concentration was set to 0.01 mol / l to complete the chemical change.

The time required to complete the chemical change was 300 minutes. At the subsequent wafer cleaning treatment (12 hours), the oxidizing agent concentration of the electrolytic sulfuric acid solution was stable.

[Comparative Example 2]

Except that the number of the electrolytic cells 30 was changed to 10 in Comparative Example 1. A chemical change was carried out using this apparatus. The existing solution was drained, and sulfuric acid and water were newly added to the washing tank 11 and the storage tank 22 so that the sulfuric acid concentration was 85%. The solution temperature in the cleaning tank 11 was set at 120 占 폚. Thereafter, the electrolytic cell 30 was energized at a current density of 0.4 A / cm 2 to generate an electrolytic sulfuric acid solution, and the oxidant concentration was 0.03 mol / l to complete the chemical change.

The time required to complete the chemical change was 300 minutes. At the subsequent wafer cleaning treatment (12 hours), the oxidizing agent concentration of the electrolytic sulfuric acid solution was stable.

[Comparative Example 3]

In Comparative Example 1, the number of electrolytic cells 30 was the same except that the number of electrolytic cells 30 was 15. A chemical change was carried out using this apparatus. The existing solution was drained, and sulfuric acid and water were newly added to the washing tank 11 and the storage tank 22 so that the sulfuric acid concentration was 85%. The solution temperature in the cleaning tank 11 was set at 150 占 폚. Thereafter, the electrolytic cell 30 was energized at a current density of 0.4 A / cm 2 to generate an electrolytic sulfuric acid solution, and the oxidant concentration was set to 0.01 mol / l to complete the chemical change.

The time required to complete the chemical change was 300 minutes. At the subsequent wafer cleaning treatment (12 hours), the oxidizing agent concentration of the electrolytic sulfuric acid solution was stable.

[Example 1]

1, a second electrolytic system 40 is provided. Four electrolytic cells 30 in the first electrolytic system and two electrolytic cells 50 in the second electrolytic system were installed. Using this apparatus, during the wafer processing, sulfuric acid and water were newly introduced into the second electrolytic system 40 into the storage tank 41 so that the sulfuric acid concentration became 85%. Electrolytic cells 30 and 50 were energized at a current density of 0.4 A / cm 2 to produce an electrolytic sulfuric acid solution, and the oxidant concentration was 0.01 mol / l. The electrolytic sulfuric acid solution of the cleaning tank 11, the pipes 12 to 16 and the first electrolytic system 20 is drained and the electrolytic sulfuric acid solution prepared in the second electrolytic system 40 And transferred from the storage tank 41 to the storage tank 22. The solution temperature in the cleaning tank 11 was set at 120 占 폚. Thus, the chemical change time (the time when the wafer can not be processed) was 60 minutes. At the subsequent wafer cleaning treatment (12 hours), the oxidizing agent concentration of the electrolytic sulfuric acid solution was stable.

[Example 2]

Except that six electrolytic cells 30 of the first electrolytic system and three electrolytic cells 50 of the second electrolytic system were provided in Example 1. Using this apparatus, during the wafer cleaning process, sulfuric acid and water were newly introduced into the second electrolytic system 40 into the storage tank 41 so that the sulfuric acid concentration was 85%. Thereafter, the electrolytic cells 30 and 50 were energized at a current density of 0.4 A / cm 2 to produce an electrolytic sulfuric acid solution, and the oxidant concentration was 0.03 mol / l. The chemical change was carried out in the same manner as in Example 1. The solution temperature in the cleaning tank 11 was set at 120 占 폚. Thus, the chemical change time (the time when the wafer can not be processed) was 60 minutes. At the subsequent wafer cleaning treatment (12 hours), the oxidizing agent concentration of the electrolytic sulfuric acid solution was stable.

[Example 3]

Except that the electrolytic cells 30 of the first electrolytic system and the electrolytic cells 50 of the second electrolytic system were installed in the same manner as in Example 1 except that eight electrolytic cells 30 and two electrolytic cells 50 of the second electrolytic system were provided. Using this apparatus, during the wafer cleaning treatment, the wafer was poured into the storage tank 41 so that the sulfuric acid concentration was 85%. Electrolytic cells 30 and 50 were energized at a current density of 0.4 A / cm 2 to produce an electrolytic sulfuric acid solution, and the oxidant concentration was 0.01 mol / l. The chemical change was carried out in the same manner as in Example 1. The solution temperature in the cleaning tank 11 was set at 150 占 폚. Thus, the chemical change time (the time when the wafer can not be processed) was 60 minutes. At the subsequent wafer cleaning treatment (12 hours), the oxidizing agent concentration of the electrolytic sulfuric acid solution was stable.

The results of Comparative Examples and Examples are shown in Table 1.

In Comparative Examples 1 to 3, it took a long time to replace the circulating liquid in the washing liquid circulating line from the electrolytic sulfuric acid producing portion of the first electrolysis system with the electrolytic sulfuric acid that had been pressurized. In Examples 1 to 3, The time required for the operation can be greatly shortened.

When the set concentration of the oxidizing agent in the electrolytic sulfuric acid is high as in Comparative Example 2, it is necessary to increase the number of electrolytic cells in the electrolytic sulfuric acid device in consideration of disappearance of persulfuric acid. In the present invention, It has been proved that the number of water additions can be suppressed.

It is necessary to increase the number of electrolytic cells in the electrolytic sulfuric acid device in consideration of the disappearance of persulfuric acid when the temperature in the cleaning tank 11 is high as in Comparative Example 3. In the present invention, It has been proved that the number of water additions can be suppressed.

While the invention has been described in detail with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

The present application is based on Japanese Patent Application No. 2016-061470 filed on March 25, 2016, the entirety of which is incorporated by reference.

11: Cleaning bath
15: Heater
20, 80: First electrolysis system
30, 50: electrolytic cell
40: Second electrolysis system
72: Rapid burner

Claims (3)

1. A persulfate solution production and supply apparatus having a first electrolysis system circulating and supplying a persulfate solution to a wafer cleaning apparatus,
A second electrolytic system for producing a persulfuric acid solution formed separately from the first electrolytic system,
And a transfer device for transferring the electrolytic solution from the second electrolytic system to the first electrolytic system. The method according to claim 1,
The first electrolytic system includes a first storage vessel for storing the persulfuric acid solution circulated to the wafer cleaning apparatus, an electrolytic treatment unit for electrolyzing the liquid supplied from the first storage vessel and returning the electrolytically treated liquid to the first storage vessel And a first electrolytic cell,
The second electrolytic system includes a second electrolytic cell, a second electrolytic cell electrolytically treating the liquid supplied from the second storage tank and returning the electrolytically treated liquid to the second storage tank, and a second electrolytic cell supplying sulfuric acid and water to the second storage tank And a device for producing and supplying the persulfuric acid solution. A method for supplying a persulfuric acid solution to a wafer cleaning apparatus using the persulfuric acid solution production and supply apparatus according to claim 1 or 2,
In at least part of the step of cleaning the wafer with the wafer cleaning apparatus, electrolytically treating the wafer with a second electrolysis system to produce a persulfate solution,
The persulfuric acid solution is discharged from the wafer cleaning apparatus and the first electrolysis system, and then the persulfuric acid solution is transferred from the second electrolysis system to the second electrolysis system at the time of replacing the persulfuric acid solution in the wafer cleaning apparatus and the first electrolysis system Wherein the sulfuric acid solution is supplied to the surface of the substrate.

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