JPH101794A - Electrolyzer and electrolysis method - Google Patents

Abstract

(57) [Summary] [Object] To provide an electrolytic cell and a method for producing cleaning water having a lower impurity content than conventional electrolytic cleaning water. [Constitution] A perfluorocarbon-based cation exchange membrane 2 is used as a diaphragm, and electrode chamber frames 5 and 6 are molded with a fluororesin, and a platinum group metal or an oxide thereof which is hardly eluted is used as a substance for electrodes 7 and 8. Electrolytic cell. When electrolysis is performed while supplying an electrolytic solution to the electrolytic cell having such a configuration, contamination of washing water generated due to elution of the electrode material and the chamber frame is prevented, and it is used for cleaning electronic equipment requiring ultra-high purity. Cleaning water that can be used effectively can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic cell and an electrolytic method for producing high-purity acidic water and / or alkaline water free of metal contamination used for cleaning electronic devices such as semiconductors and liquid crystals.

[0002]

[Prior art and its problems] For manufacturing and cleaning electronic parts,
Conventionally, sulfuric acid, hydrofluoric acid, hydrogen peroxide, hydrochloric acid and the like specially prepared for the use have been used. These will be used in the future depending on the application, but they are obtained by specially refining products manufactured by the corresponding chemical processes, and the metal components mixed in from the catalyst etc. in the manufacturing process The operation is complicated to perform the removal and the like, resulting in an expensive product. Further, even if the refining operation is carefully performed, it is not always possible to sufficiently cope with the decrease in the allowable impurity amount accompanying the advancement of electronic devices, and a new alternative method is required.

[0003] One of the alternatives is the use of ozone water. In particular, high-concentration ozone water produced by electrolysis is known to be extremely effective for cleaning electronic devices. However, the use of ozone water alone may not be sufficient, and there is an increasing need for a treatment liquid that has other functions that ozone water does not have, such as an oxidizing action and a reducing action, and that does not contain any metal components. Examples of the treatment liquid include so-called acidic water or superacidic water. The acidic water usually has a pH of 3 or less and an oxidation-reduction potential (ORP) of 1.2 V.
As described above, since it has an oxidizing power, it has an effect of decomposing organic substances or dissolving and removing metal precipitates, and is slightly used for cleaning electronic devices. At the same time as the production of the acidic water, alkaline water having a pH of 10 or more and an ORP of 0 V or less is produced as a by-product in the cathode chamber of the electrolytic cell, and studies on use of the alkaline water for cleaning and the like have been started.

[0004] During the electrolytic production of such modified acidic water or alkaline water (washing water), a two-chamber electrolytic cell divided into an anode chamber and a cathode chamber by an ion exchange membrane serving as a diaphragm is used. In order to perform electrolysis using this electrolytic cell, a suitable supporting electrolyte is added to impart ionic conductivity to the electrolytic solution. In many cases, the supporting electrolyte remains in the washing water to be produced, or the inner wall constituting material of the electrolytic cell body is dissolved in the electrolytic solution, and metal ions and particles are generated to contaminate the washing water. When used for cleaning electronic devices such as semiconductors and liquid crystals, there arises a problem that metal ions and the like in the cleaning water adhere to the semiconductor surface as impurities to cause insulation failure. When a neutral diaphragm is used as a diaphragm for partitioning the anode compartment and the cathode compartment, the two electrodes sandwiching the diaphragm are arranged close to each other to reduce the electrolytic voltage. Even in this arrangement, since the gas-liquid permeability of the diaphragm is high, various products generated in each of the electrode chambers migrate to the counter electrode chamber to cause re-oxidation or reduction, resulting in reduced efficiency, and the oxidation-reduction potential of the anolyte and the catholyte. There is a problem that it decreases.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, that is, the disadvantage that impurities such as metal ions and particles are easily mixed into the washing water generated by electrolysis and that the oxidation-reduction potential is easily lowered. An object of the present invention is to provide an electrolytic cell for producing cleaning water for electronic equipment and a method for producing the cleaning water, which enables the cleaning water to be used for cleaning semiconductors and liquid crystals.

[0008]

SUMMARY OF THE INVENTION The present invention relates to an electrolytic cell for producing acidic water. The present invention relates to a cleaning apparatus for an electronic device which is divided into an anode chamber and a cathode chamber by a cation exchange membrane having an anode catalyst and a cathode catalyst disposed on both surfaces thereof. In the electrolytic bath for producing acidic water, the cation exchange membrane is a perfluorocarbon cation exchange membrane, the anode chamber frame is formed of a fluororesin, and the anode catalyst is selected from platinum group metals and oxides thereof. One or more metals or metal oxides are used, a porous sheet made of platinum and / or carbon is used as the cathode catalyst, pure water and / or hydrochloric acid is supplied to the anode chamber, and the anode and cathode are separated. It is an electrolytic bath for producing acidic water for washing electronic equipment, which is characterized by producing acidic water in the anode chamber by energizing the acidic water, taking out the acidic water produced at that time outside the tank,
Further impurities may be removed through a cationic resin packed tower.

Further, the present invention relates to an electrolytic cell for producing alkaline water, and an electrolytic cell for cleaning alkaline water for electronic equipment which is divided into an anode chamber and a cathode chamber by a cation exchange membrane having an anode catalyst and a cathode catalyst disposed on both surfaces thereof. In the tank, the cation exchange membrane is a perfluorocarbon cation exchange membrane,
A cathode chamber frame is formed of a fluororesin, platinum and / or ruthenium oxide is used as the cathode catalyst, a cathode current collector for supplying electricity to the cathode catalyst is formed of zirconium, and pure water and / or Or supply ammonium hydroxide,
An electrolyzer for producing alkaline water for cleaning electronic equipment, characterized in that alkaline water is produced in a cathode chamber by passing an electric current between the anode and the cathode. The impurities may be further removed through a resin packed tower.

Hereinafter, the present invention will be described in detail. A feature of the present invention is that the material of the diaphragm, the electrolytic chamber frame, and the electrode catalyst is made of a material that does not completely or almost completely dissolve in the electrolytic solution, and thus, the electronic device cleaning water that does not contain impurities that is indispensable for cleaning semiconductors and the like. The point is to provide. Examples of the electronic device cleaning water produced by electrolysis include acidic water generated in the anode chamber of the electrolytic cell and alkaline water generated in the cathode chamber. The present invention provides an electrolytic cell and a production method for producing these respective cleaning waters. including. In the present invention, a perfluorocarbon cation exchange membrane is used as a solid electrolyte as a diaphragm of the electrolytic cell, and the electrolytic cell is partitioned into an anode chamber and a cathode chamber by the cation exchange membrane. The cation exchange membrane differs from the conventional neutral membrane in that the anolyte and the catholyte hardly mix with each other because the liquid permeability is almost zero. A reduction in efficiency due to partial mixing of water) can be avoided, and operation under a high current density becomes possible, and a desired amount of washing water can be obtained in a short time.

Although the reason for the details is not clear, the use of the cation exchange membrane reduces the consumption of the electrode material, thereby preventing contamination of the washing water due to the contamination of the electrode material. This is because the conductivity of the electrolyte (cation exchange membrane) is good, so that the current is not unevenly distributed, the electric resistance is reduced at least partially, and thereby the temperature rise is suppressed, and the portion in contact with the membrane is reduced. It can be inferred that due to the three-dimensional function, two turns to the electrode are substantially reduced. Empirically, when the electrolyte is platinum and the diaphragm is a non-solid electrolyte type, the sodium chloride concentration is about 1000 ppm, whereas the degree of consumption in salt water electrolysis is 10 to 30 mg / KAH,
In the case of the solid electrolyte type as in the present invention, 0.5 to 3 mg / KAH
And 1/10 to 1/20. In the present invention, a perfluorocarbon cation exchange membrane excellent in various resistances is used as the cation exchange membrane. There are two types of perfluorocarbon cation exchange membranes, a perfluorocarbon sulfonic acid type cation exchange membrane and a perfluorocarbon carboxylic acid type cation exchange membrane. In particular, the former perfluorocarbon sulfonic acid type cation exchange membrane is Even if highly oxidizable hypochlorite ion (ClO ⁻ ) or persulfate ion (S ₂ O ₈ ^2- ) is generated, the operation is extremely high and stable operation is possible.

The cation exchange membrane is stable against electrolysis even in a dilute electrolyte or pure water, and exhibits extremely high resistance to many chemicals in addition to products having high oxidizability. Next, a fluorine resin is used as an electrode chamber frame. Here, the electrode chamber frame means a portion of the electrolytic cell other than the cation exchange membrane, the electrode, and the current collector, and particularly indicates a portion in contact with the electrolytic solution among these components. included. In the present invention, at least during the electrolysis operation, the portion is formed of the fluororesin in constant contact with the electrolytic solution. It is desirable to form both electrode chamber frames with a fluororesin, but at least for the purpose of producing acidic water, form the anode chamber frame, and for the purpose of producing alkaline water, form the cathode chamber frame with a fluororesin. . That is, when the purpose is to obtain only acidic water / alkaline water, there is no problem even if the chamber frame constituents elute in the alkaline water / acidic water. The terminal group of fluorine resin is fluorine (F)
And its corrosion resistance is extremely high. In addition to high resistance to ultrapure water and hydrochloric acid, this fluororesin also exhibits extremely high resistance to radicals such as ozone generated when electrolyzing ultrapure water, and prevents elution of particles and metals from the chamber frame. It has a role of minimizing and making the obtained cleaning water usable for cleaning electronic devices such as semiconductors.

Next, in the case of producing acidic water, a substance which is resistant to dissolution during the production of acidic water as an anode material, specifically, a platinum group metal such as platinum, ruthenium, iridium, rhodium, palladium, osmium, etc. Alternatively, a platinum group metal oxide such as ruthenium oxide or iridium oxide is used. The metal or oxide is consumed very little by electrolysis, so that there is almost no elution into the washing water, and the contamination of the obtained washing water can be zero or almost zero. For example, when used as an anode material of carbon, which is another electrode material, there is a problem that carbon is oxidized by anodic reaction to generate carbon dioxide and the anode becomes weak. By using the platinum group metal or its oxide, the physical properties of the obtained acidic water can be controlled. For example, when chlorine ions are present in the electrolytic solution during electrolysis using platinum as an anode material, the chlorine ions are oxidized to hypochlorite ions, and the oxidation-reduction potential can be further increased. The pH can be lowered sufficiently. In each case, the anodic reaction is an oxygen generating reaction, but the electrode is not consumed as in the case of the carbon electrode described above.

Although the selection of the cathode material does not affect the mixing of the cathode material into the acidic water, it does not affect the reduction of the electrolysis voltage. Therefore, the selection of the cathode material needs to be considered also in the case of producing the acidic water. is there. In the production of the acidic water of the present invention, a platinum and / or carbon sheet electrode having an opening of 100 μm or less is used as a cathode. The use of platinum and / or carbon as the cathode stabilizes the electrode and minimizes elution of the cathode material. Further, since the electrode sheet having openings of 100 μm or less, preferably 4 to 50 μm, uniformly contacts the cation exchange membrane to suppress partial current concentration, the electrolysis voltage is kept low, and furthermore, the electrode sheet is generated at the cathode. Since hydrogen gas is generated uniformly on the entire surface of the cathode and gas can be smoothly vented, the rate of movement of hydrogen gas generated at the cathode to the anode chamber is suppressed, thereby lowering the oxidation-reduction potential of the anode. It is possible to suppress and keep high.

In the case of alkaline water production, platinum or ruthenium oxide is used as a cathode material. When these substances are used as cathodes, consumption by electrolysis is extremely small,
Also, since the overvoltage is low, it is effective for lowering the electrolysis voltage. For example, if a metal such as stainless steel, nickel, or titanium is used as the cathode instead of the platinum or ruthenium oxide, the overvoltage is large, the electrolysis voltage is increased, and the power cost is increased. If metal ions eluted in water are mixed in and the cleaning water is used for cleaning semiconductors and liquid crystals, the risk of causing insulation failure due to the metal ions increases. Further, in the production of alkaline water, zirconium is used as a cathode current collector. This is because, similarly, stainless steel and nickel other than zirconium have large elution and are not suitable for cleaning electronic equipment.

For the purpose of producing acidic water, pure water and / or hydrochloric acid are supplied to the anode chamber of the above-mentioned electrolytic cell, and electricity is supplied between the anode and the cathode. When only pure water is supplied, the cation exchange membrane functions as an electrolyte to generate oxygen (including ozone) by water electrolysis, and the oxygen dissolves in the anolyte to generate acidic water. When hydrochloric acid is supplied to the anode chamber, chlorine ions are electrolytically oxidized to chlorine gas and further to hypochlorite ions, and acidic water having low pH and strong oxidizing power is generated. Note that a small amount of cations may be mixed in the acidic water produced in this manner, and in the method of the present invention, the obtained acidic water is led to a cation resin packed tower installed outside the electrolytic cell and the charged water is charged. Cationic impurities are removed through a column to obtain more pure acidic water.

On the other hand, for the purpose of producing alkaline water, pure water and / or ammonium hydroxide are supplied to the above-mentioned cathode chamber of the electrolytic cell, and electricity is supplied between the anode and the cathode. When only pure water is supplied, the cation exchange membrane functions as an electrolyte, and hydroxyl ions are generated by water electrolysis, and alkaline water is generated. When ammonium hydroxide is supplied to the cathode chamber, the concentration of hydroxyl ions increases, and stronger alkaline water is generated. In this case, a small amount of anions may be mixed in the alkaline water produced in this manner, and in the method of the present invention, the obtained alkaline water is introduced into an anion resin packed tower installed outside the electrolytic cell and the packed water is charged. Anionic impurities are removed through a column to obtain alkaline water of higher purity.

In the production of acidic water and / or alkaline water according to the present invention, the use of a perfluorocarbon cation exchange membrane as a diaphragm suppresses the consumption and elution of electrode materials, and the electrolysis chamber frame is made of fluororesin. It is possible to suppress the elution of the chamber frame material and to suppress the consumption and elution of the electrode material by selecting the electrode material, and to completely or minimize the contamination of the washing water generated by combining these effects with the effect. It is possible to provide cleaning water that can be effectively used for cleaning electronic devices requiring ultra-high purity.

FIG. 1 is a schematic longitudinal sectional view illustrating the electrolytic cell of the present invention. The electrolytic cell main body 1 has a frame-shaped anode chamber gasket 3 and a cathode chamber gasket 4 sandwiching a perfluorocarbon-based cation exchange membrane 2, and each gasket 3, 4 on a surface opposite to the cation exchange membrane 2. It is provided with an anode chamber wall plate 5 and a cathode chamber wall plate 6 having a function of flowing an electrolytic solution and having at least a portion in contact with the inner electrolytic solution made of a fluororesin. The cation exchange membrane 2
A porous anode 7 made of a powder of a platinum group metal or an oxide thereof is provided in close contact with the anode surface, and a porous sheet made of platinum or carbon is provided on the cathode surface of the cation exchange membrane 2. Cathode 8 is provided in close contact. An anode current collector 9 and a cathode current collector 10 are connected to the anode 7 and the cathode 8, respectively, and electricity is supplied through the current collector.

An anolyte flow passage is provided inside the anode chamber wall plate 5.
An anolyte dissolved in hydrochloric acid or the like supplied from an anolyte inlet 12 enters the anode chamber through the anode chamber opening 13 and comes into contact with the anode 7 to form a high oxidizing power such as hypochlorous acid. It is oxidized to a compound having a redox potential and is taken out from the anolyte outlet 14 as acidic water. On the other hand, a catholyte flow passage 15 is formed inside the cathode chamber wall plate 6, and ultrapure water supplied from the catholyte inlet 16 as necessary enters the cathode chamber through the cathode chamber opening 17 and contains ions. It is reduced by contact with the cathode 8 together with the water transferred from the anode, and is taken out from the catholyte outlet 18 as alkaline water. In the cleaning water production using the electrolytic cell shown in the figure, a cation exchange membrane is used as a diaphragm, the electrode chamber wall plate is formed of a fluororesin, and no eluting or little substance is used as an electrode substance. The amount of impurities mixed into the obtained washing water is zero or very small, and it is possible to provide washing water containing almost zero impurities, which is particularly preferable for cleaning electronic equipment.

[0021]

EXAMPLES Next, examples of the production of cleaning water using an electrolytic cell for producing cleaning water for electronic equipment according to the present invention will be described, but the examples do not limit the present invention.

[0022]

Example 1 A gas-liquid permeable titanium porous anode supporting an iridium oxide catalyst and covering the entire substrate was placed on the anode side of a cation exchange membrane Nafion 117 (manufactured by DuPont). Cathodes made of a platinum carbon sheet having an opening of 10 to 20 microns and a thickness of 100 microns were adhered to the respective sides. A current collector made of zirconium was connected to the cathode. This cation exchange membrane was installed in an electrolytic cell body formed entirely of Teflon (manufactured by DuPont) and partitioned into an anode chamber and a cathode chamber to constitute the electrolytic cell shown in FIG. Electrolysis was performed at a temperature of 25 ° C. and a current of 5 A while supplying 40 mmol hydrochloric acid to the anode compartment of the electrolytic cell and pure water to the cathode compartment at 300 ml / min and 300 ml / min, respectively. An acidic water having an oxidation-reduction potential of 1150 mV and a pH of 4.5 is collected at a rate of 300 ml / min from the anode compartment outlet, and at the same time an alkaline water having an oxidation-reduction potential ORP of -680 mV and a pH of 7.5 from the cathode compartment outlet. Was collected at 300 ml per minute. Analysis of the impurities in the acidic water indicated that iridium and aluminum contained 40%.
ng / l was detected, but no other metals were detected at the detection limit of 5 ng / l.

[0023]

Comparative Example 1 Electrolysis was carried out under the same conditions as in Example 1 except that a platinum mesh of 40 mesh was used for the cathode to obtain acidic water and alkaline water. The electrolysis voltage was 5.5 V, and as impurities in the obtained acidic water, 100 ng / l of iridium was detected and 100 ng / l of iron was further detected.

[0024]

Comparative Example 2 Example 1 was repeated except that the ion exchange membrane was changed to a porous ceramic made of alumina and silica.
Electrolysis was performed under the same conditions as in Example 1 to obtain acidic water and alkaline water. The oxidation-reduction potential of the obtained acidic water was 650 mV, and the electrolysis voltage also exceeded 7.0 V.

[0025]

According to the present invention, an electrolytic cell for producing acidic water is provided.
In an electrolyzer for producing acidic water for cleaning electronic equipment, which is partitioned into an anode chamber and a cathode chamber by a perfluorocarbon cation exchange membrane in which an anode catalyst and a cathode catalyst are arranged on both surfaces thereof,
An anode chamber frame is formed of a fluororesin, and one or more metals or metal oxides selected from platinum group metals and oxides thereof are used as the anode catalyst, and platinum and / or carbon are used as the cathode catalyst. Using a porous sheet, supplying pure water and / or hydrochloric acid to the anode chamber, and supplying an electric current between the anode and the cathode to produce acidic water in the anode chamber, thereby producing acidic water for cleaning electronic equipment. It is an electrolytic cell for use.

In the present invention, the use of a highly durable perfluorocarbon cation exchange membrane capable of preventing current uneven distribution or the like as a diaphragm suppresses the consumption and elution of electrode materials,
It is possible to suppress elution of the chamber frame material by making the electrolysis chamber frame made of a fluororesin, and to suppress consumption and elution of the electrode material by selecting the electrode material, and into the acidic water generated by combining these effects. It is possible to provide an acidic water for cleaning that can be used effectively for cleaning electronic equipment in which ultra-high purity is suppressed by completely or minimizing the contamination of impurities.
Further, in the present invention, since the cathode is made into a sheet shape and the cathode is uniformly contacted with the cation exchange membrane to suppress the partial current concentration, the electrolysis voltage is kept low, and hydrogen gas generated at the cathode is reduced over the entire surface of the cathode. It is possible to generate the gas on average and to smoothly release the gas, whereby the reduction in the oxidation-reduction potential of the anode can be suppressed and kept high. Also, a small amount of cations may be mixed in the acidic water thus produced. In the present invention, the obtained acidic water is led to a cation resin packed column installed outside the electrolytic cell, and the packed column is charged. To remove cationic impurities to obtain acidic water of higher purity.

In the present invention relating to the electrolytic cell for producing an alkaline water, the material for the above-mentioned acidic water can be obtained by appropriately selecting the materials of the cation exchange membrane, the cathode chamber frame, the cathode catalyst and the cathode current collector in the same manner. Alkaline water for cleaning that can be used effectively for cleaning electronic equipment in which ultra-high purity is suppressed by completely or minimizing the contamination of the generated alkaline water with impurities as in the case of an electrolytic cell. Can be provided. Further, a small amount of anions may be mixed in the alkaline water produced in this manner. In the present invention, the obtained alkaline water is led to an anion resin packed column installed outside the electrolytic cell and the packed column is charged. To remove anionic impurities to obtain alkaline water of higher purity.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view illustrating an electrolytic cell of the present invention.

[Explanation of symbols]

1 ・ ・ ・ Electrolyzer main body 2 ・ ・ ・ Cation exchange membrane 2 3 ・
..Anode compartment gasket 4 ・ ・ ・ Cathode compartment gasket 5 ・ ・ ・ Anode compartment wall plate 6 ・
..Cathode room wall plate 7 ・ ・ ・ Anode 8 ・ ・ ・ Cathode 9 ・ ・
・ Anode current collector 10 ・ ・ ・ Cathode current collector 11 ・ ・ ・ Anolyte flow passage 12 ・ ・ ・ Anolyte inlet 13 ・ ・ ・ Anode chamber opening 14
・ ・ ・ Anolyte outlet 15 ・ ・ ・ Cathode flow passage 16 ・ ・ ・ Cathode inlet 17 ・ ・ ・ Cathode opening 18 ・ ・ ・ Cathode outlet

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naoaki Sakurai 33 Shinisogocho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside Toshiba Production Technology Research Institute (72) Inventor Naoya Hayami 33 shares, Shinisogocho, Isogo-ku, Yokohama-shi, Kanagawa Company Toshiba Production Technology Laboratory

Claims (4)

[Claims] 1. An electrolytic cell for producing acidic water for cleaning electronic equipment, which is divided into an anode chamber and a cathode chamber by a cation exchange membrane having an anode catalyst and a cathode catalyst disposed on both surfaces thereof, wherein the cation exchange membrane is a perfluorocarbon. A cation exchange membrane, wherein the anode chamber frame is formed of a fluororesin, and the anode catalyst is one or two selected from platinum group metals and oxides thereof.
Using the above metal or metal oxide, using a porous sheet made of platinum and / or carbon as the cathode catalyst,
An electrolytic cell for producing acidic water for cleaning electronic equipment, wherein pure water and / or hydrochloric acid are supplied to the anode chamber, and an electric current is supplied between the anode and the cathode to produce acidic water in the anode chamber. 2. An anode catalyst comprising, on both surfaces thereof, one or more metals or metal oxides selected from platinum group metals and oxides thereof, and a cathode catalyst comprising a porous sheet made of platinum and / or carbon. Is divided into an anode chamber and a cathode chamber by a perfluorocarbon cation exchange membrane provided with
Pure water and / or hydrochloric acid are supplied to the anode chamber of the electrolytic bath for producing acidic water for electronic equipment cleaning whose electronic chamber frame is formed of a fluororesin, and an electric current is supplied between the anode and the cathode. And removing impurities from the acidic water through a cation resin packed tower outside the tank. 3. An electrolyzer for producing alkaline water for cleaning electronic equipment, which is divided into an anode chamber and a cathode chamber by a cation exchange membrane having an anode catalyst and a cathode catalyst disposed on both surfaces thereof, wherein the cation exchange membrane is made of perfluorocarbon. A cation exchange membrane, wherein the cathode chamber frame is formed of a fluororesin, and platinum and / or ruthenium oxide is used as the cathode catalyst, and a cathode current collector for supplying electricity to the cathode catalyst is formed of zirconium; An electrolyzer for producing alkaline water for cleaning electronic equipment, wherein pure water and / or ammonium hydroxide is supplied to the cathode chamber, and electricity is supplied between the anode and the cathode to produce alkaline water in the cathode chamber. 4. An anode catalyst, and platinum and / or
Or, a perfluorocarbon-based cation exchange membrane provided with a cathode catalyst made of ruthenium oxide is partitioned into an anode chamber and a cathode chamber, and the cathode chamber frame is formed of a fluororesin. Supplying pure water and / or ammonium hydroxide to the cathode chamber and supplying electricity between the anode and the cathode to produce alkaline water in the cathode chamber, and removing the alkaline water through an anion resin packed tower outside the tank. A method for producing alkaline water for cleaning electronic equipment, comprising: