JP2002059164A - Washing water in which hydrogen ions or hydroxy ions and oxidation-reduction substance due to electrolysis of pure water coexist and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solution in which H+ ions or OH- ions and oxidation- reduction substance coexist without adding pair ions by electrolyzing pure water. SOLUTION: By using an electrolytic bath having a structure in which an anode electrode and a cathode electrode are adhered to both sides of ion exchange resin, and changing kinds of electrode material and ion exchange membrane, H+ ions or OH- ions are selectively formed and pH of water is made acidic or alkaline, and also oxidation-reduction substances such as H free radicals, OH free radicals, H2, O2, O3 and H2O2, are made to coexist.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolysis of high-purity water, which is used for washing or surface cleaning with hydrogen ions in excess of the counter ion concentration or water in which hydroxide ions and redox species coexist. It is to provide water suitable for treatment.

[0002]

BACKGROUND OF THE INVENTION Water pH and redox capacity are very important factors in the field of cleaning or surface treatment. First, the role of pH and oxidation-reduction ability in the field of washing and how it controls pH and oxidation-reduction ability will be described.

[0003] Contaminants to be cleaned are classified into ionic substances, reaction products, and liquid or particulate substances. Contamination forms of ionic substances include adsorption by ion exchange on glass surfaces, adhesion of ions on semiconductor and metal surfaces by electrostatic attraction, and intrusion by diffusion of ions into semiconductor, metal, and ceramic surface layers. It is roughly divided into Contamination by reaction products falls into this category due to the deposition and deposition of impurities in water, such as boiler scale, and oxide films or rust generated on metal surfaces.

On the other hand, the mechanism of contamination by particulate matter is complicated. Attachment by a chemical bond, attachment by a physicochemical bond such as van der Waals force or hydrogen bond, and physical attachment by an electrostatic force or a magnetic force.

Among the above contaminants, ionic substances are:
It is common to wash with high-purity water such as pure water or ultrapure water. In the case of a semiconductor or the like, the electric resistivity is about 18%.
Ultra pure water of MΩ / cm is used. The reaction product is usually washed with a chemical. For the scale and the like, a drug in which an acid and a chelating agent are combined is used. In particular, citric acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid and the like have both functions, and therefore these drugs are often used.

[0006] On the other hand, the removal rate of the oxide film on the metal surface by dissolution is strongly dependent on the pH and the redox ability. For example, ferric oxide (Fe ₃ O ₄ ) constituting an oxide film of iron
Is well soluble in acidic and reducing aqueous solutions having a pH of about 4 or less. Representative agents for dissolving these oxide films include a combination of oxalic acid, citric acid, and ethylenediaminetetraacetic acid. Here, oxalic acid is an acid and also acts as a reducing agent. On the other hand, the surface oxide film of chromium steel dissolves in an oxidizing solution. Representative agents include a combination of sodium hydroxide and potassium permanganate, or a combination of hydrofluoric acid and nitric acid.

In the field of semiconductor silicon wafer cleaning, there is a case where cleaning is performed by etching a surface layer. In this case, a combination of ammonia water and peroxide water, sodium hydroxide, nitric acid and the like are used as the cleaning liquid. As in the case of silicon wafer cleaning, a method of oxidatively decomposing or dissolving contaminants is applied to remove liquid or film-like contaminants. Specifically, in the case of oxidative decomposition,
There is a combination of sulfuric acid (H ₂ SO ₄ ) and hydrogen peroxide (H ₂ O ₂ ), or a combination of ammonium hydroxide (NH ₄ OH) and H ₂ O ₂ . When dissolving an inorganic substance, hydrochloric acid (HCl) and H ₂ O ₂ , H ₂ S
O ₄ and H ₂ O ₂ , HCl and nitric acid (HNO ₃ ), and a combination of H ₂ SO ₄ and HNO ₃ . When an organic substance is dissolved, an organic chlorine-based solvent such as trichloroethane or dichloroethane is used.

As is apparent from the above description, the pH of water
And redox capacity play an important role in cleaning and surface treatment. In order to make the pH of water acidic or alkaline and to provide redox ability, there are a method of adding a chemical agent and a method of utilizing electrolysis. In order to shift the pH to acidic using a chemical, an acid is used,
Cl ⁻ , SO ₂ ⁻ , NO ₃ as counter ions of ⁺ ions
^-, _CH 3 COO ^- it is necessary that the anions such exist. On the other hand, in order to shift the pH to alkaline, since a base is used, it is necessary that metal ions such as Na ⁺ , K ⁺ , and Ca ²⁺ coexist as counter ions of OH ⁻ ions. Thus, when using chemicals, it is not possible to add H ⁺ or OH ⁻ ions to water without counterions.

As a method of controlling the pH without using a chemical, there is an electrolytic method. Specifically, a diaphragm electrolysis method in which a diaphragm is provided between a cathode and an anode is used. In the conventional diaphragm electrolysis method, there is a distance between the cathode and the diaphragm and the anode, and it is necessary to lower the electric resistance of the liquid in order to perform electrolysis. For this purpose, it is essential to add an electrolyte, that is, a salt to water. When a solution to which a salt composed of an anion and a cation is added is electrolyzed, the anion moves to the anode and the cation moves to the cathode. As a result, the anode compartment becomes acidic and the cathode compartment becomes alkaline. Therefore, in the conventional electrolysis method, the counter ion increases as the H ⁺ ion or the OH ⁻ ion increases.

[0010]

When an acid or alkali and an oxidation-reduction agent are used in the washing or surface treatment step, counter ions coexist with H ⁺ or OH ^- ions, and after washing or surface treatment, these counter ions coexist. Residual ions are a problem. For example, in the case of cleaning metals, corrosion may occur if anions remain. In particular, it is well known that halogen ions such as Cl ⁻ accelerate corrosion. In the case of a semiconductor, it is necessary to avoid ionic impurities remaining on the surface regardless of anions and cations. It is known that when these ionic impurities remain, they serve as a trapping source for carriers and deteriorate the performance of the semiconductor. In order to remove these residual ions, it is necessary to perform sufficient rinsing after chemical cleaning. Particularly in the field of semiconductors, a large amount of water is used for rinsing.
Specifically, several tons of water are required per silicon wafer. In recent years, the shortage of water resources has become a problem, and reducing the amount of water used is becoming an urgent and important issue from the viewpoint of securing production.

If cleaning or surface treatment can be performed with the decomposition products of H ₂ O without using chemicals, the problem of residual ions is greatly reduced. By the way, H ₂ O is known to decompose according to the following oxidation-reduction reaction. Here, E. Is the standard redox potential.

O ₂ + H + e ⁻ ← HO ₂ E. = −0.13 V (1) 2H ⁺ + 2e ⁻ ← → H ₂ E. = + 0.0 V (2) O ₂ + 2H ⁺ + 2e ⁻ ← → H ₂ O ₂ E. = + 0.69 V (3) H ₂ O ₂ + H ⁺ + e ⁻ ← → OH · + H ₂ O E. = + 0.71 V (4) O ₂ + 2H ⁺ + 4e ⁻ ← → 2H ₂ O E. = + 1.229 V (5) HO ₂ + H ⁺ + e ⁻ ← → H ₂ O ₂ E. = + 1.495 V (6) H ₂ O ₂ + 2H ⁺ + 2e ⁻ ← → 2H ₂ O E. = + 1. 77 V (7) O ₃ + 2H ⁺ + 2e ⁻ ← → O ₂ + H ₂ O E. = + 2.07 V (8) OH ⁻ + H ⁺ + e ⁻ ← → H ₂ O E. = + 2.85 V (9) H ₂ O + e ⁻ ← → H · + OH ⁻ E. = −2.93 V (10) 2H ₂ O + 2e ⁻ ← → H ₂ + 2OH ⁻ E. _{= -0.828V (11) O 2 +} 2H 2 O + 4e - ← → 4OH - E. = −0.401V (12) O ₂ + H ₂ O + 2e ⁻ ← HO ₂ + OH ⁻ E. = −0.08 V (13) HO ₂ ⁻ + H ₂ O + 2e ⁻ ← → 3OH ^- E. = + 0.76 V (14) O ₃ + H ₂ O + 2e ⁻ ← → O ₂ + 2OH ⁻ E. = + 1.24 V (15) OH ⁻ + e ⁻ ← → OH ^- E. = + 2.02 V (16) As is apparent from the above reaction formula, H ⁺ ions, OH ⁻ ions, H radicals, OH radicals, H ₂ , O ₂ , HO are converted from H ₂ O by the oxidation-reduction reaction. _{2, O 3}
Attention is paid to an electrolysis method as a method for generating the above. The electrolytic reaction generally depends on the electrolyte of the aqueous solution, the electrode material, the current density and the electrolytic voltage. If an electrolyte is included in water to produce a decomposition product by electrolysis, the result is the same as that when a counter ion is added.Therefore, it is necessary to use water whose electrolyte concentration, that is, impurities as low as possible, as a starting material. It is.

Note that H ₂ O ₂ , H ₂ , O ₂ , O ₃
Redox species such as can be purified after electrolytic generation. These species made in the electrolyte solution,
It may be added to water containing H ⁺ ions or OH ⁻ ions. In either case, it is necessary to obtain water containing H ⁺ ions or OH ⁻ ions without adding a counter ion.

According to the present invention, the electric resistance is 0.01 MΩ / cm.
By electrochemically treating the above pure water or ultrapure water of 10 MΩ / cm or more, H
⁺ Ions or OH ⁻ ions are generated, and these are converted to H ₂ O ₂ , OH radical, H radical, H ₂ ,
An object of the present invention is to provide water suitable for cleaning and surface treatment by combining redox species such as O ₂ and O ₃ .

[0015] no counterions H ⁺ ions or OH, ^- in order to obtain an aqueous solution containing ions, it is necessary to use pure water or ultrapure water as raw water. Electrolyzing pure water is usually difficult due to high electrical resistance,
This becomes possible by using the electrolytic cell shown in FIG. 1 or FIG.

The structure of these electrolytic cells will be described below.

As shown in FIG. 1, an electrolytic cell 4 having a structure in which a cathode 2 and an anode 3 are closely attached to both sides of an ion exchange membrane 1 is used. The cathode chamber 9 is provided with an inlet 5 and an outlet 6, and the anode chamber 10 is provided with an inlet 7 and an outlet 8. In such a configuration, for example, a cation exchange group (-
When a cation exchange membrane into which (SO ₃ H group) is introduced is used,
Electrolysis voltage can be reduced to several volts (V), and electrolysis of pure water or ultrapure water can be easily performed.

At the anode electrode, an oxidizing substance such as O ₂ or O ₃ is generated, which is transferred to the cathode chamber via the ion exchange membrane, and the performance of the reduced species generated at the cathode electrode may be reduced. Conceivable. When these problems are concerned, the electrolytic cell shown in FIG. 2 is effective. In the electrolytic cell 25 shown in FIG.
Reference numeral 3 denotes a cathode electrode, 14 denotes an anode electrode, 15 denotes an inlet of the cathode chamber 21, 16 denotes the same outlet, 17 denotes an inlet of the anode chamber 22, 18 denotes the same outlet, 19 denotes an inlet of the intermediate chamber 23, and 20 denotes the same outlet. . By passing water having a reduced dissolved oxygen concentration (DO) through the intermediate chamber 23, the permeation of oxidizing substances generated at the anode electrode is prevented. Dissolved oxygen concentration (DO) using high purity nitrogen N2 (or argon Ar) gas
Lower.

In the electrolytic cell shown in FIG. 1, for example, platinum is used for the anode and the cathode, and Nafion 117 manufactured by DuPont is used as the ion exchange membrane. The reaction of equation (2) occurs. Specifically, H ⁺ ions generated at the anode are reduced to H 2 at the cathode, and no change in pH is observed with the water in the anode chamber and the water in the cathode chamber. However, the water in the anode chamber becomes oxidizing due to generation of O ₂ , and the water in the cathode chamber becomes reducing due to generation of H _2, but the object of the present invention is not achieved because there is no change in pH.

[0020]

It is known that an electrochemical reaction strongly depends on a reaction overpotential, which is a measure of the likelihood of an electrode reaction. Since the ideal hydrogen overvoltage of platinum is as very small as 0 V, H ⁺ ions adsorbed on the surface of platinum, which is the cathode, are easily reduced to hydrogen atoms and then quickly changed to H ₂ gas. FIG.
Even if platinum is used for the anode and the cathode in the electrolytic cell of No. 1 and Nafion 117 is used as the ion exchange membrane, no change in pH can be obtained. Therefore, if carbon having a hydrogen overvoltage of 0.6 V higher than platinum is used for the electrode, H ⁺
The ion reduction reaction is less likely to occur, and H around the electrode is reduced.
^{+ The} ion concentration increases. By passing water through the electrode in such a situation, H ⁺ ions are partially removed.
As a result, acidic water having no counter ion and a high H ⁺ ion concentration can be obtained. Some of the H ⁺ ions are reduced to H radicals (H atoms) or H ₂ gas, so that the electrolytic solution contains a reducing chemical species. Thus, an acidic and reducing liquid containing no counter ion is obtained. It is desirable that carbon be fired at a relatively low temperature of 500 ° C. to 800 ° C. Since low-temperature fired carbon has a large electric resistance, for example, carbon fired at 1000 ° C. or more may be further coated with carbon fired at 500 to 800 ° C. In order to obtain such a liquid, an electrode material having a higher hydrogen overvoltage than platinum may be used, and is not limited to a carbon electrode. Mercury and its metal compounds, lead and the like are also useful. The ion exchange membrane is not limited to Nafion 117, but is preferably a material in which a —SO ₃ H group or a —COOH group is bonded to a fluororesin. It is desirable that the current density is low as the electrolysis condition,
A value of about 20 mA / cm ² or less is suitable. It is desirable that the flow velocity on the electrode surface is high, and the linear velocity on the electrode surface is 1 cm.
/ Sec is desirable. When an acid is put into the intermediate chamber in the electrolytic cell shown in FIG. 2, anions are eliminated by the cation exchange resin membrane, and H ⁺ ions can be supplied to the cathode chamber. Is obtained.

Next, in the electrolytic cell of FIG. 1, when platinum is used for the anode and cathode electrodes as the anion exchange membrane as the ion exchange membrane, unlike the cation exchange membrane, the surface of platinum as the cathode electrode is H + There are no ions. Specifically, Nafion 117 is reacted with ethylenediamine (NH ₂ CH ₂ CH ₂ NH ₂ ) as an anion exchange membrane,
Fluororesin of a film _{to -SO 2} NHCH 2 CH 2 NH 2 group is attached as an exchange group may be used. When electrolysis is performed in a state where H + ions are insufficient, the cathode reaction is (1).
As shown by the equation (0) or the equation (11), a reductive decomposition reaction of H ₂ O occurs. As is apparent from these equations, OH ⁻ ions are generated around platinum. At the same time, H radicals or H ₂ gas are generated. In this way, alkaline and reducing water without counterions is obtained.

As the anion exchange membrane, fluororesin-S
O₂ NHCH₂CH₂ NH₂ Limited to membranes with attached groups
It is not an exchange membrane with cation exchange groups
It can be used. In this case, the electrolytic current density is high.
Is more desirable, 5 mA / cm ² The above is suitable. Through
The water velocity should be 1 cm / sec or more as the linear velocity on the electrode surface.
desirable. Platinum, palladium, stainless steel as electrodes
Alkaline such as steel, gold, silver, carbon steel, nickel alloy, steel
A metal that is stable in a solution of is preferred. 1000 ℃
Graphite fired at the above high temperature is also effective.

On the other hand, water is oxidatively decomposed by anodic electrolysis.
H₂ From O, according to equation (5) or (8)
And H⁺ Ions are generated. In the electrolytic cell of Fig. 1
When a cation exchange membrane is used for the ion exchange membrane,⁺
 The ions move to the cathode compartment, and the pH of the solution in the anode compartment
Does not change. When an anion exchange membrane is used, H⁺ Io
Do not transfer to the cathode compartment and remain in the anode compartment
And the pH shifts to the acidic side. At this time the cathode
OH generated at the pole⁻ When ions are removed through the water,
The change in pH on the node side is large. In addition, the anode electrode
The solution is dissolved as shown in equations (5) and (8).₂Or
O₃A gas is generated and has oxidizing performance. Shade
As an on-exchange membrane, -SO₂ NH₂ CH
₂ CH₂ NH ₂ Groups such as anion exchange groups
Membrane is preferred, but the anion exchange group is a special exchange group.
It is not limited. 2 mA / electrolysis current density
cm²The above is desirable, and the water flow rate is 1 cm /
sec or more is desirable. For anode reaction as electrode material
Stable platinum, palladium, lead oxide (β-PbO₂ )But
desirable.

Further, as a method different from the electrolyte, H ⁺ ions or OH ion exchange resins ^- a method of obtaining a water containing ions. For example, when immersing the ion-exchange resin having a -SO ₃ H group in pure water or ultrapure water, -SO ₃ as part of the -SO ₃ H group following formula _{^{H ← → -SO 3 - + H}} + Partially dissociated. Since the dissociated H ⁺ ions migrate into water, the use of water makes it possible to use water containing H ⁺ ions without adding a counter ion. On the other hand, as redox species, H ₂ , O ₂ , H ₂
O ₂ and O ₃ can be generated by electrolysis. The redox species containing no impurity ions can be obtained by electrolytically producing these redox species using an electrolyte solution in order to increase the electrolysis efficiency and then purifying them. H ⁺
By adding the redox species to the water in which the ions are present, the water of the present invention can be obtained. As a cation exchange resin, an ion exchange resin in which —SO ₃ H groups are bonded to a fluororesin, and a styrene-divinylbenzene (DVB) resin—
An ion exchange resin to which an SO ₃ H group is bonded is desirable. Specifically, Nafion NR-50 manufactured by DuPont and Amberlite manufactured by Organo (trade name: Amberlite)
e) IR-116, IR-118, IR-120B, I
R-122, Diaion manufactured by Mitsubishi Kasei Corporation (trade name: D
iaion) SK102, SK104, SK1B, SK
110, SK116, Dowex (trade name; Dowex) manufactured by Dow Chemical Company, HCR-W2, HCR-S, H
GR-W and the like.

On the other hand, OH⁻When making water containing ions
It is preferable to use an anion exchange resin. Anion exchange
Bases Nafion NR-50 and NH₂ CH₂CH
₂NH₂To styrene-DVB other than the resin reacted with
-N⁺(CH₃ )₃Group, -NC₂ H₅OH (CH
₃)₂ Ion exchange resins with attached groups are preferred. Concrete
Specifically, Amberlite IRA-401, IRA-40
2, IRA-400, IRA-430, IRA-41
1, IRA-410 (manufactured by Organo), Diaion
SA11A, SA12A, SA10A, SA21A, S
A20A (Mitsubishi Kasei), Dowex SBP-P,
SBR, SAR (manufactured by Dow Chemical Company) and the like.
You. Thus, the water containing OH- ions contains H₂ , O
₂ , O₃ Or H ₂O₂The present invention by adding
The desired water is obtained.

By the above method, an acidic and reducing or oxidizing aqueous solution and an alkaline and reducing or oxidizing aqueous solution can be obtained without adding a counter ion. In the case of cleaning the iron-based metal surface oxide film, an acidic and reducing aqueous solution is effective. For washing the aluminum-based metal having the amphoteric oxide film, an acidic or alkaline and reducing aqueous solution is effective. Humoral used when washing, such as a silicon wafer is dependent on the contamination forms, firstly H ⁺ ions or OH ^- solution combining ion and the oxidizing substances are suitable. On the other hand, an alkaline and reducing aqueous solution is effective for washing vinyl chloride resin, acrylic resin and the like.

[0027]

EXAMPLE 1 In the electrolytic cell shown in FIG. 1, 80 mesh platinum was used for the anode and activated mesh glass carbon (RVC) was used for the cathode. The size of platinum is 80 × 60mm
The dimensions of the RVC are 90 × 70 × 25 mm and its surface area is about 800 m ² / g.

This electrolytic cell was incorporated in the apparatus shown in FIG. 26 indicates an electrolytic cell, 27 indicates a cathode chamber, and 28 indicates an anode chamber. A pipe 31 is connected to the cathode chamber, and a tank 29 is provided on the outlet side. The water accumulated in the tank is recirculated to the electrolytic cell using the circulation pump 30. Fluorine resin such as tetrafluoroethylene resin was used as the material of the equipment and piping. The capacity of the tank is 3 liters and the circulating water volume is 1 liter /
min. The electrolysis current is set to 0.5A and about 1MΩ
/ Cm of pure water was subjected to constant current electrolysis. The pH was measured with a glass electrode, and the oxidation-reduction potential was determined using silver / silver chloride (A
g / AgCl) electrode was measured using platinum as the sample electrode.

FIG. 4 shows the change over time in pH. The pH shifted to the acidic side with the start of electrolysis, and after about 10 minutes, about 4.65.
Became. SO ₄ as anion that may elute
² and F ^- there is. When the electrolyte was sampled and analyzed using ion chromatography, each concentration was 0.1 ppm or less. When 0.01 N sodium hydroxide (NaOH water) was titrated to this electrolyte,
The amount of NaOH used was less than the theoretical value for the measured pH, but the pH returned to neutral. These results indicate that H ⁺ ions are generated in the electrolyte. On the other hand, a value of about -0.527 V was obtained as the oxidation-reduction potential. In general, the oxidation-reduction potential of water at pH 4.6 is about +0.25 V, and the oxidation-reduction potential of the electrolytic solution is more negative than this potential, indicating that the solution is reducible.

In order to confirm the effect of this electrolytic solution, heating was performed at 700 ° C. for about 2 minutes in air, and Fe ₃
The carbon steel on which O ₄ was formed was immersed in the tank described above and washed. FIG. 5 shows the change with time of the elution amount of the oxide. In the figure, the curve 1 shows the result of washing in the electrolytic solution in the above-mentioned tank, and the curve 2 shows the result of washing in pure water. The elution amount of the oxide in the electrolytic solution is larger by one digit or more than the elution amount of the oxide in pure water, which indicates the effectiveness of the present invention.

Example 2 Using the electrolytic cell shown in FIG.
A 80-mesh platinum mesh with a size of 60 cm was used, and a carbon electrode with an outer size of 80 x 60 mm was used as a cathode. The carbon electrode uses polycarbodiimide as a starting material,
A sheet having a thickness of 0.5 mm and a shape shown in FIG.
It was fired at 0 ° C. After the same resin was further coated on the surface of this electrode, it was fired again at about 750 ° C. The intermediate chamber has dimensions of 90 × 70 × 25 cm, and contains Nafion NR50, which is a cation exchange resin, for about 160.
g. Nafion 117 as a cation exchange membrane was used as an ion exchange membrane as a diaphragm. This electrolytic cell was incorporated in the device shown in FIG.

In FIG. 7, the electrolytic cell 32 is a cathode chamber 3.
3. It comprises an intermediate chamber 34 and an anode chamber 35.
Ultrapure water is supplied from the ultrapure water production device 36 to the electrolytic cell using a pump 37. The solution subjected to cathodic electrolysis is supplied to a pipe 39.
And is stored in the tank 38. The overflowing liquid is discharged via a pipe 40. Pass degassed pure water to the intermediate room. Pure water is put into the degassing tank 41, and the water is bubbled from the N ₂ gas cylinder 42 through the pipe 44 using the bubbler 43. Pure water with DO reduced by bubbling is supplied to the intermediate chamber using the piping 46 and the circulation pump 45. Stop valves 47 and 4 are provided at the exit and entrance of the intermediate chamber.
8 and the material of the liquid contact surface of the equipment / piping was a fluororesin as in Example 1.

At a flow rate of 1 liter / min, 16.5 MΩ /
cm of ultrapure water was passed through the electrolytic cell in one direction, and constant current electrolysis was performed at an electrolytic current of 0.25A. The flow rate is also 0 in the intermediate chamber.
Water degassed with N ₂ gas was passed at 5 liter / min. DO was about 20 ppb. The glass electrode and the platinum electrode were put in the tank 38, and the pH and the oxidation-reduction potential were measured. The pH will be in the range of 6-5 and the redox potential will be about-
It was 0.65V. The oxidation-reduction potential is in a more negative direction than in Example 1, and it is considered that a stronger reducing species is generated. One of the reduced species candidates is, for example, H (hydrogen radical).

Next, in the above-mentioned electrolytic cell, Nafion 117 provided in the cathode chamber and the intermediate chamber was removed, and Nafion NR filled in the intermediate chamber was brought into direct contact with the carbon electrode. At this time, the valves 47 and 48, which are the inlet and outlet valves of the intermediate chamber, were closed. Constant current electrolysis was performed at the same flow rate of 1 liter / min and electrolysis current of 0.25 A as in the above electrolysis conditions.
The pH was between 5 and 4, and a more acidic liquid was obtained.

Example 3 In the electrolytic cell shown in FIG. 1, an anion exchange membrane in which --SO ₃ NHOH ₂ OH ₂ NH ₂ groups were bonded to a fluororesin was used as an ion exchange membrane, and 8 was used for an anode and a cathode.
Platinum of 80 × 60 mm with 0 mesh was used. This electrolytic cell was incorporated into the apparatus of FIG.
/ Cm of pure water was circulated at a flow rate of 1 liter / min, and constant current electrolysis was performed at an electrolysis current of 1.5 A. A glass electrode, a platinum electrode and the tank 2 were put into the tank 2 to measure pH and oxidation-reduction potential. FIG. 8 shows the change over time in pH. As is apparent from the figure, the pH reached 10.5 after about 15 minutes. The oxidation-reduction potential became about -1.0V. The redox potential was about -0.1 V when an aqueous solution having a pH of 10.5 was prepared by adding NaOH to pure water. The oxidation-reduction potential of the electrolyte is -0.1
It is in a direction more base than V and shows strong reducing properties. Thus, an alkaline reducing electrolyte was obtained without adding a counter ion.

The cleaning effect of this electrolytic solution was confirmed for a printed substrate soldered. One printed board of about 50 × 50 mm was placed in an electrolyte of pH 10 in a tank 2 for 3 hours.
The other printed circuit boards were immersed in pure water having a resistance of 1 MΩ / cm for 30 seconds. After immersion, the surface of each printed circuit board was rinsed with pure water. The amount of ions remaining on the surface of the print substrate was evaluated by measuring the conductivity of the waste liquid that had been washed off. FIG. 9 shows the relationship between the number of times of washing and the conductivity of the waste liquid. In the figure, curve 1 shows the case where the printed board is immersed in pure water, and curve 2 shows the case where the printed board is immersed in the electrolytic solution. As can be seen from the figure, the conductivity of the waste liquid decreases rapidly when immersed in the electrolytic solution. This indicates that the electrolytic solution has a higher cleaning effect than pure water.

Example 4 In the electrolytic cell shown in FIG. 2, platinum having a size of 80 × 60 mm and 80 × 60 mm was used for the anode and the cathode, and Nafion 117 was used as the ion exchange membrane.
160 g of R50 were charged. In this example, Nafion 11
7 between the cathode and the cathode, 100
A mesh net was inserted as a spacer. A glass electrode and a platinum electrode were immersed in a tank in which this electrolytic cell was incorporated into a one-through system shown in FIG. 6, and the pH and the oxidation-reduction potential of the electrolytic solution were measured. Ultrapure water having an electric resistance of 16.5 MΩ / cm was passed at a flow rate of 1 liter / min, and an electrolytic current of 1.
Constant current electrolysis was performed at 5 A. The pH was between 9.5 and 10, and the oxidation-reduction potential was about -0.8V. It has been proved that the insertion of the spacer reduces the amount of H ⁺ ions adsorbed on the surface of the platinum cathode to cause reductive decomposition of H ₂ O.

Example 5 In the electrolytic cell shown in FIG. 1, --SO ₂ NH was added to the ion exchange membrane.
Using an anion exchange membrane having OH ₂ OH ₂ NH ₂ groups,
80 × 60m with 80 mesh for anode and cathode
m of platinum was used. This electrolytic cell was used in the same manner as in Example 2 and FIG.
Was installed in the circulation type device shown in (1). However, unlike Example 2, the anode chamber was connected to the circulation line. That is, the anode electrolyte was circulated. A glass electrode and a platinum electrode were immersed in the tank.

Pure water having an electric resistance of 1 MΩ / cm was circulated at a flow rate of 1 liter / min, and was subjected to constant current electrolysis at a current of 0.5 A. FIG. 10 shows the change over time in pH. PH after 15 minutes
Reached 4.75. The oxidation-reduction potential is + 0.4V
And an acidic electrolyte solution was obtained.

Example 6 In the electrolytic cell shown in FIG.
Approximately 160 g of Nafion NR-50 was filled in the intermediate chamber using platinum having a mesh size of 80 × 60 mm. In this example, the ion exchange membrane between the anode and Nafion NR-50 was removed, and Nafion 117 was inserted only between the cathode and Nafion NR-50. Example 2
It was incorporated into the device shown in FIG. However, unlike Example 2, the anode chamber was connected to a one-through line. Specifically, the anode chamber is 33 and the cathode chamber is 35
And Further, the valves 48 and 47 at the entrance and exit of the intermediate chamber were closed. Ultrapure water of 16.5 MΩ / cm was flowed through the electrolytic cell at a flow rate of 1 liter / min in a one-through manner, and was electrolyzed at a constant current of 1.5 A. The glass electrode and the platinum electrode were put in the tank 38, and the pH and the oxidation-reduction potential were measured. The pH dropped to 5-4 and the redox potential was about 0.45V. When the pH is simply adjusted to 5 to 4 using an acid, the oxidation-reduction potential becomes 0.2
０．３0.3V. It can be seen that the potential of the electrolyte is more noble than this potential and is oxidizing. Further, since O ₃ was generated from the electrolytic solution, it is considered that O ₃ contributed to this oxidation-reduction potential.

Example 7 Styrene-based strongly acidic cation exchange resin IR-120B (E
First, concentrated sulfuric acid was added to the ion-exchange group (Na form)
Using -SO₃Na to -SO₃Change to H shape
The on-exchange resin was sufficiently washed with pure water. 10 final washings
0 ml was sampled, and 0.01 mol (M) of salt was added to this.
10cc of an aqueous solution of barium bromide was added,
I didn't see it. From this result, elution from ion exchange resin
SO ₄ ^2-Ion is determined to be 0.1 ppm or less
You.

Take 5 g of ion exchange resin, and add about 1 M
Add 100 cc to Ω / cm pure water and leave for 10 minutes. The supernatant was taken and the pH was measured with a glass electrode. A value of 3.6 was obtained. 0.01 in 40 ml of supernatant
When 0.4 ml of M NaOH aqueous solution was added, the pH of the glass electrode was 6.3. From this result, it can be seen that H ⁺ ions are present in the supernatant. That is, an acidic liquid was obtained without adding a counter ion.
By adding 30% H ₂ O ₂ to this, an acid and oxidizing liquid can be obtained without adding a counter ion.

The effect of this solution was evaluated by the speed of removing fingerprints attached to the glass surface. 40 ml of the above acidic water
Solution containing 1 g of 30% H ₂ O ₂ and 30% pure water
A liquid to which 1 g of H ₂ O ₂ was added was prepared. Two glasses with fingerprints were prepared, immersed in each liquid, and left in a container for about 1 hour. Observation of the surface condition for one hour revealed that the fingerprint on the surface of the glass immersed in the acidic liquid was removed, but the fingerprint remained on the pure water. From these results, the effectiveness of the acidic and oxidizing liquid is judged.

Example 8 In the electrolytic cell shown in FIG.
A platinum electrode having a size of 80 × 60 mm was used, a cathode electrode was a carbon electrode having carbon fired at about 750 ° C. as in Example 2, and anions were removed from Nafion 117 and Nafion 117 as a diaphragm. Both competent Nafion 324 were used in tandem. The intermediate chamber was filled with 170 g of Amberlite 15 (manufactured by Organo Corporation). This electrolytic cell was incorporated in the device shown in FIG.

Ultrapure water is supplied from the ultrapure water producing apparatus 36 shown in FIG. The solution subjected to cathodic electrolysis is stored in a tank 38 via a pipe 39. The overflowed liquid is discharged through the pipe 40. H in the intermediate chamber tank 41
^In order to supply more ⁺ ions, a solution in which polyacrylic acid is dissolved at 0.01M is added. The polyacrylic acid itself does not move to the cathode chamber by the cation exchange membrane. This liquid is bubbled from a N2 gas cylinder 42 through a pipe 44 using a bubbler 43.
The solution with the dissolved oxygen concentration (DO) reduced by bubbling,
The water is supplied to the intermediate chamber by using a pipe 46 and a circulation pump 45.

At a flow rate of 1 liter / min, 16.5 MΩ
/ Cm of ultrapure water is allowed to flow in the cathode chamber in one direction. In this state, a constant current analysis at an electrolytic current of 0.25 A was performed. A deaerated aqueous solution of polyacrylic acid was passed through the intermediate chamber at 0.5 L / min. Tank 3
8, a glass electrode and a platinum electrode were inserted, and the pH and the oxidation-reduction potential were measured. The pH dropped to 5-4 and the redox potential was about -0.7V. By placing the polyacrylic acid solution in the intermediate chamber, a stronger acidic liquid was obtained than in Example 2.

[0047]

As described above, according to the present invention,
An acidic or alkaline liquid having redox performance can be obtained without using anions such as Cl ⁻ , SO ₄ ²⁻ and NO ₃ ⁻ and cations such as Na ⁺ and K ⁺ .

According to the present invention, the following effects can be obtained.

The acidic and reducing liquid is effective for dissolving and removing an oxide film or rust on a metal surface, and for cleaning a surface while preventing oxidation of a silicon wafer. An even greater advantage is that Cl can promote metal corrosion after cleaning.
^{It is} a trap source for ions or electrons of silicon semiconductors; Since harmful ions such as Na ⁺ and K ⁺ ions do not remain, the amount of pure water or ultrapure water used for final cleaning can be reduced. The acidic oxidizing liquid is effective for decomposing and removing organic substances attached to the surface of a silicon wafer, glass, or the like. Cl remains on the surface, such as with the printed circuit board reducing the liquid alkaline ^- removal rate of such ion is greater than just pure water. When the electrolytic solution is used, the removal rate of the ionic impurities is increased, and the cooling water can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a configuration outline of an electrolytic cell used in the present invention,

FIG. 2 is a diagram showing a schematic configuration of an electrolytic cell used in the present invention;

FIG. 3 is a diagram showing an outline of a configuration of a test apparatus used in Example 1.

FIG. 4 is a diagram showing the results of Example 1.

FIG. 5 is a diagram showing the results of Example 1.

FIG. 6 is a diagram showing a carbon electrode incorporated in the electrolytic cell used in Example 2,

FIG. 7 is a diagram showing an outline of the configuration of a test apparatus used in Example 2.

FIG. 8 is a diagram showing the results of Example 3.

FIG. 9 shows the results of Example 5.

FIG. 10 shows the results of Example 6.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ion exchange membrane, 2 ... Cathode pole, 3 ... Anode pole,
4 ... electrolyzer, 5 ... into the cathode chamber, 6 ... outlet in the cathode chamber,
7 ... Anode compartment inlet, 8 ... Anode compartment outlet, 9 ... Cathode compartment, 10 ... Anode compartment, 11, 12 ... Ion exchange membrane,
13: cathode electrode, 14: anode electrode, 15: cathode chamber inlet, 16: cathode chamber outlet, 17: anode chamber inlet, 18: anode chamber outlet, 19: intermediate chamber inlet, 20 ...
Intermediate chamber outlet, 21: cathode chamber, 22: anode chamber, 2
3 ... Intermediate chamber, 25 ... Electrolyzer, 26 ... Electrolyzer, 27 ... Cathode, 28 ... Anode, 29 ... Tank, 30 ... Circulation pump, 31 ... Piping, 32 ... Electrolyzer, 33 ... Cathode, 34 ... Intermediate chamber, 35 Anode chamber, # 6 Ultrapure water production equipment, 37 Pump, 38 Tank, 39 Pipe, 4
0: Waste liquid pipe, 41: Degassing tank, 42: Nitrogen cylinder, 43: Bubbler, 44: Nitrogen gas pipe, 45: Pump, 46: Pipe, 47: Intermediate chamber inlet, 48: Intermediate chamber outlet.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 4, 2001 (2001.7.4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

Patent application title: Cleaning water in which hydrogen ion or hydroxyl ion and redox substance coexist by electrolysis of pure water and method for producing the same

[Claims]

3. Pure water or ultrapure water without adding anions.
A method for producing cleaning water using, as raw water, pure water or ultrapure water that produces H ⁺ ions and a redox substance in the electrolyzed water by electrolysis of the water .

4. Pure water or ultrapure water without adding a cation.
The electrolytic water by the electrolytic water OH ^- pure water or producing <br/> method of cleaning water to the ultrapure water raw generating ions and redox substances.

5. The method according to claim 3, wherein a cation-exchange membrane and a cation-exchange resin are used as a diaphragm structure for electrolysis, and an electrode is used as a cathode electrode, the surface of which is made of carbon which is obtained by firing an organic substance at 600 to 800 ° C. , pure water or ultra-generating H ⁺ ions and hydrogen atom, hydrogen molecules or hydrogen peroxide
A method for producing cleaning water using pure water as raw water .

6. The method according to claim 3, wherein a cation exchange membrane and a cation exchange resin are used as a diaphragm structure for electrolysis, and platinum or β-type lead oxide is used as an anode to generate H ⁺ , ozone, and oxygen molecules. Pure water or ultrapure water as raw water
A method for producing washing water .

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for cleaning or surface treatment of semiconductors by electrolyzing high-purity water.
Another object of the present invention is to provide water having a concentration of hydrogen ions or hydroxide ions in excess of the counter ion concentration and water having a redox species and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Water pH and redox capacity are very important factors in the field of cleaning or surface treatment. In the following, first, a general idea of how the pH and the oxidation-reduction ability play in the field of cleaning and how the pH and the oxidation-reduction ability are controlled will be described.

[0003] Contaminants to be cleaned are classified into ionic substances, reaction products, and liquid or particulate substances. Contamination forms of ionic substances include adsorption by ion exchange on glass surfaces, adhesion of ions on semiconductor and metal surfaces by electrostatic attraction, and intrusion by diffusion of ions into semiconductor, metal, and ceramic surface layers. It is roughly divided into Contamination by reaction products falls into this category due to the deposition and deposition of impurities in water, such as boiler scale, and oxide films or rust generated on metal surfaces.

On the other hand, the mechanism of contamination by particulate matter is complicated. Attachment by a chemical bond, attachment by a physicochemical bond such as van der Waals force or hydrogen bond, and physical attachment by an electrostatic force or a magnetic force.

Among the above contaminants, ionic substances are:
It is common to wash with high-purity water such as pure water or ultrapure water. In the case of a semiconductor or the like, the electric resistivity is about 18%.
MΩ / cm ultrapure water (that is, almost no ions
Water) is used. Further, the reaction product is usually washed with a chemical. For the scale and the like, a drug in which an acid and a chelating agent are combined is used. In particular, citric acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid and the like have both functions, and therefore these drugs are often used.

[0006] On the other hand, the removal rate of the oxide film on the metal surface by dissolution is strongly dependent on the pH and the redox ability. For example, ferric oxide (Fe ₃ O ₄ ) constituting an oxide film of iron is
It dissolves well in acidic and reducing aqueous solutions having a pH of about 4 or less. Representative agents for dissolving these oxide films include a combination of oxalic acid, citric acid, and ethylenediaminetetraacetic acid. Here, oxalic acid is an acid and also acts as a reducing agent. On the other hand, the surface oxide film of chromium steel dissolves in an oxidizing solution. Representative agents include a combination of sodium hydroxide and potassium permanganate, or a combination of hydrofluoric acid and nitric acid.

In the field of semiconductor silicon wafer cleaning, there is a case where cleaning is performed by etching a surface layer. In this case, a combination of ammonia water and peroxide water, sodium hydroxide, nitric acid and the like are used as the cleaning liquid. As in the case of silicon wafer cleaning, a method of oxidatively decomposing or dissolving contaminants is applied to remove liquid or film-like contaminants. Specifically, in the case of oxidative decomposition,
Combination of sulfuric acid (H ₂ SO ₄ ) and hydrogen peroxide (H ₂ O ₂ ), or ammonium hydroxide (NH ₄ OH) and H ₂
There is a combination of O _{2 and} the like. When dissolving an inorganic substance, hydrochloric acid (HCl) and H ₂ O ₂ , H ₂ SO ₄ and H ₂
O ₂ , HCl and nitric acid (HNO ₃ ) and H ₂ SO ₄ and H
For example, a combination of NO ₃ . When an organic substance is dissolved, an organic chlorine-based solvent such as trichloroethane or dichloroethane is used.

As is clear from the above general description,
The pH and redox capacity of water play important roles in cleaning and surface treatment. The pH of the water to an acidic or alkaline, in order to impart a redox capability, Ri method of adding chemicals Oh, in the case of an acid in order to shift the pH acidified with chemicals H ⁺ ions Cl ⁻ , SO ₂ ⁻ , NO ₃ ⁻ , CH ₃ CO as counter ions of
O ^- will be the anions such exists, whereas in the case of using a salt group in order to shift the pH to an alkaline O
H ^- Na ⁺ as a counter ion of the ion, ^K +, it is necessary to coexist metal ions such as ^{Ca 2+.} In the method using a chemical as described above, H ⁺ or O
It is not possible to add H ^- ions to water.

As a method of controlling the pH without using a chemical, an electrolysis method is generally known, and specifically, a space such as an ion exchange membrane between a cathode and an anode is used. A membrane electrolysis method provided with a membrane is known . However, the conventional diaphragm electrolysis has the following conditions. In other words, the cathode pole,
Septum, structurally distance there Runode between the anode electrode, will require an be reduced the electrical resistance of the liquid in order to electrolysis,
The electrolyte for this, namely salts and the Tsu indispensable be added to the water. When a solution to which a salt composed of an anion and a cation is added is electrolyzed, the anion moves to the anode and the cation moves to the cathode. As a result, the anode compartment becomes acidic and the cathode compartment becomes alkaline. Therefore, in the conventional electrolysis method, the counter ion increases as the H ⁺ ion or the OH ⁻ ion increases.
As a representative technique of such electrolysis, the electricity of saline solution
Known production method of caustic soda (NaOH) by decomposition
However, it is a technology that contains a large amount of ions.
The technology of using non-electrolytic pure water, which hardly exists, as raw water
It cannot be applied and no suggestion is given.

[0010]

SUMMARY OF THE INVENTION As described above, the general
The electrolysis method known in Japan has almost no ions such as pure water.
It is not common sense for those skilled in the art to use raw water that does not exist.
At the right time, without adding ionic substances, in pure water or ultrapure water.
In addition, H ⁺ or OH ⁻ can be present in excess.
Technology, or the
H ⁺ or OH using pure or ultrapure water that does not come as raw water
Der which it has been made to provide excess wash water ^-
You. The above is further explained as follows. Sand
In the washing or surface treatment step, when an acid or alkali and an oxidation-reduction agent are used for washing water , H ⁺ or OH
^- it will be the counterion coexist with ions, after the cleaning or surface treatment, the residual of these ions is problematic. For example, in the case of cleaning metals, corrosion may occur if anions remain. In particular, it is well known that halogen ions such as Cl ⁻ accelerate corrosion. In the case of a semiconductor, it is necessary to avoid ionic impurities remaining on the surface regardless of anions and cations.
It is known that when these ionic impurities remain, they serve as a trapping source for carriers and deteriorate the performance of the semiconductor. In order to remove these residual ions, it is necessary to perform sufficient rinsing after chemical cleaning. Particularly in the field of semiconductors, a large amount of water is used for rinsing. Specifically, several tons of water are required per silicon wafer. In recent years, the shortage of water resources has become a problem, and reducing the amount of water used is becoming an urgent and important issue from the viewpoint of securing production.

If cleaning or surface treatment can be performed with the decomposition products of H ₂ O without using chemicals, the problem of residual ions is greatly reduced. By the way, H ₂ O is known to decompose according to the following oxidation-reduction reaction.
Here, E. Is the standard redox potential.

O ₂ + H + e ⁻ ← → HO ₂ E. = −0.13 V (1) 2H ⁺ + 2e ⁻ ← → H ₂ E. = + 0.0 V (2) O ₂ + 2H ⁺ 12e ⁻ ← → H ₂ O ₂ E. = + 0.69 V (3) H ₂ O ₂ + H ⁺ + e ⁻ ← → OH · + H ₂ O E. = + 0.71 V (4) O ₂ + 2H ⁺ + 4e ⁻ ← → 2H ₂ O E. = + 1.229 V (5) HO ₂ + H ⁺ + e ⁻ ← → H ₂ O ₂ E. = + 1.495 V (6) H ₂ O ₂ + 2H ⁺ + 2e ⁻ ← → 2H ₂ O E. = + 1. 77 V (7) O ₃ + 2H ⁺ + 2e ⁻ ← → O ₂ + H ₂ O E. = + 2.07 V (8) OH ⁻ + H ⁺ + e ⁻ ← → H ₂ O E. = + 2.85 V (9) H ₂ O + e ⁻ ← → H · + OH ⁻ E. = −2.93 V (10) 2H ₂ O + 2e ⁻ ← → H ₂ + 2OH ⁻ E. _{= -0.828V (11) O 2 +} 2H 2 O + 4e - ← → 4OH - E. = −0.401V (12) O ₂ + H ₂ O + 2e ⁻ ← HO ₂ + OH ⁻ E. = −0.08 V (13) HO ₂ ⁻ + H ₂ O + 2e ⁻ ← → 3OH ^- E. = + 0.76 V (14) O ₃ + H ₂ O + 2e ⁻ ← → O ₂ + 2OH ⁻ E. = + 1.24 V (15) OH ⁻ + e ⁻ ← → OH ^- E. = + 2.02 V (16) As is apparent from the above reaction formula, H ⁺ ions, OH ⁻ ions, H radicals, OH radicals, H ₂ , O ₂ , HO are converted from H ₂ O by the oxidation-reduction reaction. Electrolysis is noted as a method for generating ₂ , O _{3 and the} like , and the electrolysis reaction generally depends on the electrolyte of the aqueous solution, the electrode material, the current density, and the electrolysis voltage. Therefore, when an electrolyte is contained in water to produce a decomposition product by electrolysis, the same result as that when a counter ion is added is obtained. Therefore, starting with water (pure water or the like) in which the electrolyte concentration, that is, impurities are reduced as much as possible. It is necessary to use it as a substance. However, electrolyze pure water etc.
That has not been considered before.

Incidentally, redox species such as H ₂ O ₂ , H ₂ , O ₂ , and O ₃ can be purified after electrolytic generation. These species made in an electrolytic solution, H ⁺ ions or OH ^- may be added to the water containing ions. In either case, it is necessary to obtain water containing H ⁺ ions or OH ⁻ ions without adding a counter ion.

According to the present invention, the electric resistance is 0.01 MΩ / cm.
By electrochemically treating the above pure water or ultrapure water of 10 MΩ / cm or more, H
⁺ Ions or OH ⁻ ions, which are converted to H
₂ O ₂ , OH radical, H radical, H ₂ , O ₂ ,
An object is to provide water suitable for cleaning and surface treatment by combining redox species such as O ₃ .

[0015]

Means and Action for Solving the Problems Electrochemical reaction
Is the reaction overvoltage, which is a measure of the likelihood of electrode reaction.
It is known to depend strongly on Ideal platinum water
Since the element overvoltage is very small at 0 V,
H ⁺ ions adsorbed on the surface of platinum
After being reduced to H ₂ , it is quickly changed to H ₂ gas. Fig. 1
Platinum was used for the anode and cathode electrodes in the
Even if Nafion 117 is used as the on-exchange membrane, p
No change in H is obtained. Therefore, hydrogen overcharge compared to platinum
If the pressure is as high as 0.6 V and carbon is used for the electrode, H ⁺ ion
Reaction of H + ion around the electrode
Concentration increases. Pass water through the electrode in such a situation
As a result, H ⁺ ions are partially removed. This result
No ions, high H ⁺ ion concentration and acidic water
Will be. Some H ⁺ ions are H radicals
(H atom) or H ₂ gas,
The lysis solution will contain reducing species,
It is acidic and reducible without the counter ion which is one of the purposes of
Will be obtained. 500 ° C for carbon
Baked at a relatively low temperature of from 800 to 800 ° C.
Low-temperature fired carbon has a large electric resistance.
500 ~ on carbon fired above 000 ° C
May be coated with carbon fired at 800 ° C
No. To obtain such a liquid, a hydrogen overvoltage
Use only electrode materials with high carbon content, limited to carbon electrodes
It is not something to be done. Mercury and its metal compounds, lead
Useful for everyone. Ion exchange membrane is also limited to Nafion 117
Although not intended to be constant, -SO ₃ H group in the fluorine resin, or
Or a material to which a -COOH group is bonded is desirable. Electrolysis conditions
It is preferable that the current density is low, and about 20 mA / cm
² or less is suitable. It is desirable that the flow velocity on the electrode surface be faster.
It is desirable that the linear velocity on the electrode surface be 1 cm / sec.
No. In the electrolytic cell shown in FIG.
The anion is eliminated by the cation exchange resin membrane
Thus, it is possible to supply H ⁺ ions to the cathode chamber.
And a more acidic liquid is obtained.

[0016] does not have a counter ion ^{H +} ions or O,
H ^- In order to obtain an aqueous solution containing ions, it is necessary to use pure water or ultrapure water as raw water. Electrolysis of pure water is usually difficult due to high electrical resistance.
Alternatively, it becomes possible by using the electrolytic cell shown in FIG.

[0017] In the following, a description is given of the structure of these electrolytic cells.

As shown in FIG . 1, an electrolytic cell 4 having a structure in which a cathode 2 and an anode 3 are closely attached to both sides of an ion exchange membrane 1 is used. The cathode chamber 9 is provided with an inlet 5 and an outlet 6, and the anode chamber 10 is provided with an inlet 7 and an outlet 8. In such a configuration, for example, a cation exchange group (-
When a cation exchange membrane into which SO ₃ H group is introduced is used, it is possible to lower the electrolysis voltage to several volts (V),
Electrolysis of pure water or ultrapure water can be easily performed.

At the anode electrode, an oxidizing substance such as O ₂ or O ₃ is generated, which is transferred to the cathode chamber via the ion exchange membrane, and the performance of the reduced species generated at the cathode electrode may be reduced. Conceivable. When these problems are concerned, the electrolytic cell shown in FIG. 2 is effective. In the electrolytic cell 25 shown in FIG.
Is a cathode electrode, 14 is an anode electrode, 15 is a cathode chamber 2
Reference numeral 1 denotes an inlet, 16 denotes the same outlet, 17 denotes an inlet of the anode chamber 22, 18 denotes the same outlet, 19 denotes an inlet of the intermediate chamber 23, and 20 denotes the same outlet. By passing water having a reduced dissolved oxygen concentration (DO) through the intermediate chamber 23, the permeation of oxidizing substances generated at the anode electrode is prevented. Dissolved oxygen concentration (DO) using high purity nitrogen N2 (or argon Ar) gas
Lower.

In the electrolytic cell shown in FIG . 1, for example, platinum is used for the anode and the cathode, and Nafion 117 manufactured by DuPont is used as the ion exchange membrane. The reaction of equation (2) occurs. Specifically, H ⁺ ions generated at the anode are reduced to H ₂ at the cathode, and no change in pH is observed with the water in the anode chamber and the water in the cathode chamber. However, the water in the anode chamber becomes oxidizing due to generation of O ₂ , and the water in the cathode chamber becomes reducing due to generation of H _2, but the object of the present invention is not achieved because there is no change in pH.

Next, in the electrolytic cell of FIG. 1, when platinum is used for the anode and cathode electrodes as the anion exchange membrane as the ion exchange membrane, unlike the cation exchange membrane, the surface of platinum which is the cathode electrode has H ⁺ Ions do not exist. Specifically, as an anion exchange membrane, a fluororesin membrane in which Nafion 117 is reacted with ethylenediamine (NH ₂ CH ₂ CH ₂ NH ₂ ) and an —SO ₂ NHCH ₂ CH ₂ NH ₂ group is bonded as an exchange group can be used. . When electrolysis is performed in a state where the H + ions are insufficient, the cathode reaction becomes a reductive decomposition reaction of H ₂ O as shown by the equation (10) or (11). As is clear from these equations, OH
^- so ions are generated. At the same time, H radicals or H ₂ gas are generated. In this way, alkaline and reducing water without counterions is obtained.

As the anion exchange membrane, fluororesin-S
The membrane is not limited to a membrane to which O ₂ NHCH ₂ CH ₂ NH ₂ groups are bonded, and any exchange membrane to which cation exchange groups are bonded can be used. In this case, a higher electrolytic current density is desirable, and 5 mA / cm ² or more is suitable. The water flow speed is desirably 1 cm / sec or more as a linear speed on the electrode surface. Platinum, palladium, stainless steel, gold,
A metal that is stable in an alkaline solution such as silver, carbon steel, nickel alloy, and steel is desirable. In addition, graphite fired at a high temperature of 1000 ° C. or more is also effective.

On the other hand, water is oxidatively decomposed by anodic electrolysis, and is converted from H ₂ O according to the equation (5) or (8).
H ⁺ ions are generated. In the electrolytic cell of FIG. 1, when a cation exchange membrane is used as the ion exchange membrane, H ⁺ ions move to the cathode compartment, and the pH of the liquid in the anode compartment does not change. With the use of an anion exchange membrane, H ⁺ ions do not migrate to the cathode compartment, but remain in the anode compartment, and the pH increases.
Shifts to the acidic side. OH generated in this case the cathode ^- the ions removed in passing water, pH of the anode side
Changes are large. Further, as can be seen from the equations (5) and (8), the anode electrolyte generates O ₂ or O ₃ gas, and has an oxidation performance. As the anion exchange membrane, a membrane in which an anion exchange group such as —SO ₂ NHCH ₂ CH ₂ NH ₂ group is bonded to a fluororesin is desirable, but the anion exchange group is not limited to a special exchange group. Absent. The electrolytic current density is desirably ² mA / cm ² or more, and the water flow rate is desirably 1 cm / sec or more as the linear velocity. As an electrode material, platinum, palladium, and lead oxide (β-PbO ₂ ), which are stable to an anodic reaction, are desirable.

Further, as a method different from the electrolyte, H ⁺ ions or OH ion exchange resins ^- a method of obtaining a water containing ions. For example, when immersing the ion-exchange resin having a -SO 3 _H group in pure water or ultrapure water, a part of the -
The SO ₃ H group is partially dissociated as follows ^: —SO ₃ H →→ SO ₃ ⁻ + H ⁺ . Since the dissociated H ⁺ ions migrate into water, the use of water makes it possible to use water containing H ⁺ ions without adding a counter ion. On the other hand, H ₂ , O ₂ , H ₂ O ₂ ,
O _{3 and the} like can be generated by electrolysis. The redox species containing no impurity ions can be obtained by electrolytically producing these redox species using an electrolyte solution in order to increase the electrolysis efficiency and then purifying them. By adding the redox species to the water in which the above H ⁺ ions are present, the water of the present invention can be obtained. Ion exchange resin -SO 3 _H group bonded to the fluorocarbon resin as the cation exchange resin, a styrene -
Ion exchange resin -SO ₃ H group bonded to divinylbenzene (DVB) resin is preferable. Specifically, Nafion NR-50 manufactured by DuPont and Amberlite (trade name: Amberlite) IR-116, I manufactured by Organo.
R-118, IR-120B, IR-122, manufactured by Mitsubishi Kasei Corporation, Diaion SK10
2, SK104, SK1B, SK110, SK116,
Dowex manufactured by Dow Chemical Company (trade name: Dowe)
x) HCR-W2, HCR-S, HGR-W and the like.

On the other hand, when preparing water containing OH ^- ions, it is preferable to use an anion exchange resin. Nafion NR-50 and NH ₂ CH ₂ CH ₂ NH as anion exchange groups
₂ to the styrene-DVB other than the resin reacted with -N
⁺ _{(CH 3)} 3 _{groups, -NC 2 H 5 OH (CH} 3) ion exchange _{resin 2} group is attached is desirable. Specifically, Amberlite IRA-401, IRA-402, IRA-
400, IRA-430, IRA-411, IRA-4
10 (manufactured by Organo), Diaion SA11A, S
A12A, SA10A, SA21A, SA20A (Mitsubishi Kasei), Dowex SBP-P, SBR, SAR
(Manufactured by Dow Chemical Company). Like this
H ₂ , O ₂ , O ₃ or H ₂ O ₂ is added to water containing H ⁻ ions.
The water of the present invention can be obtained by adding water.

By the above method, an acidic and reducing or oxidizing aqueous solution and an alkaline and reducing or oxidizing aqueous solution can be obtained without adding a counter ion. In the case of cleaning the iron-based metal surface oxide film, an acidic and reducing aqueous solution is effective. For washing the aluminum-based metal having the amphoteric oxide film, an acidic or alkaline and reducing aqueous solution is effective. Humoral used when washing, such as a silicon wafer is dependent on the contamination forms, firstly H ⁺ ions or OH ^- solution combining ion and the oxidizing substances are suitable. Meanwhile, vinyl chloride resin,
An alkaline and reducing aqueous solution is effective for washing acrylic resin and the like.

[0027]

EXAMPLE 1 In the electrolytic cell shown in FIG. 1, 80 mesh platinum was used for the anode and activated mesh glass carbon (RVC) was used for the cathode. The size of platinum is 80 × 60mm
The dimensions of the RVC are 90 × 70 × 25 mm and its surface area is about 800 m ² / g.

This electrolytic cell was incorporated in the apparatus shown in FIG. 26 indicates an electrolytic cell, 27 indicates a cathode chamber, and 28 indicates an anode chamber. A pipe 31 is connected to the cathode chamber, and a tank 29 is provided on the outlet side. The water accumulated in the tank is recirculated to the electrolytic cell using the circulation pump 30. Fluorine resin such as tetrafluoroethylene resin was used as the material of the equipment and piping. The capacity of the tank is 3 liters and the circulating water volume is 1 liter /
min. The electrolysis current is set to 0.5A and about 1MΩ
/ Cm of pure water was subjected to constant current electrolysis. The pH was measured with a glass electrode, and the oxidation-reduction potential was determined using silver / silver chloride (A
g / AgCl) electrode was measured using platinum as the sample electrode.

FIG. 4 shows the change over time in pH. pH is electrolysis
Shifted to the acidic side with the start, and about 4.65 after 10 minutes
Became. SO as an anion that may elute₄
^2- And F-. Sampling the electrolyte
When analyzed using chromatography, each concentration was
It was 0.1 ppm or less. This electrolyte is 0.01N
When sodium hydroxide (NaOH water) was titrated,
The amount of NaOH used is a theoretical
Although less than the value, the pH returned to neutral. These conclusions
Fruit is H in the electrolyte⁺Indicates that ions are being generated
You. On the other hand, the value of about -0.527 V is
Obtained. In general, the redox potential of pH 4.6 water is
About +0.25 V, and the oxidation-reduction potential of the electrolyte is
The solution is more negative than the potential, indicating that the solution is reducible.
Call

In order to confirm the effect of this electrolytic solution, heating was performed at 700 ° C. for about 2 minutes in air, and Fe ₃ O
_The carbon steel formed with No. ₄ was immersed in the above-mentioned tank and washed. FIG. 5 shows the change with time of the elution amount of the oxide. In the figure, the curve 1 shows the result of washing in the electrolytic solution in the above-mentioned tank, and the curve 2 shows the result of washing in pure water. Compared to the elution amount of oxide in pure water, the elution amount in the electrolytic solution is 1
This is more than an order of magnitude, which indicates the effectiveness of the present invention.

Example 2 Using the electrolytic cell shown in FIG.
A 80-mesh platinum mesh with a size of 60 cm was used, and a carbon electrode with an outer size of 80 x 60 mm was used as a cathode. The carbon electrode uses polycarbodiimide as a starting material,
A sheet having a thickness of 0.5 mm and a shape shown in FIG.
It was fired at 0 ° C. After the same resin was further coated on the surface of this electrode, it was fired again at about 750 ° C. The intermediate chamber has dimensions of 90 × 70 × 25 cm, and contains Nafion NR50, which is a cation exchange resin, for about 160.
g. Nafion 117 as a cation exchange membrane was used as an ion exchange membrane as a diaphragm. This electrolytic cell was incorporated in the device shown in FIG.

In FIG. 7, the electrolytic cell 32 is a cathode chamber 3.
3. It comprises an intermediate chamber 34 and an anode chamber 35.
Ultrapure water is supplied from the ultrapure water production device 36 to the electrolytic cell using a pump 37. The solution subjected to cathodic electrolysis
And is stored in the tank 38. The overflowing liquid is discharged via a pipe 40. Pass degassed pure water to the intermediate room. Pure water is put into the degassing tank 41, and the water is bubbled from the N ₂ gas cylinder 42 through the pipe 44 using the bubbler 43. Pure water with DO reduced by bubbling is supplied to the intermediate chamber using the piping 46 and the circulation pump 45. Stop valves 47 and 4 are provided at the exit and entrance of the intermediate chamber.
8 and the material of the liquid contact surface of the equipment / piping was a fluororesin as in Example 1.

At a flow rate of 1 liter / min, 16.5 MΩ /
cm of ultrapure water was passed through the electrolytic cell in one direction, and constant current electrolysis was performed at an electrolytic current of 0.25A. The flow rate is 0 in the intermediate chamber.
Water degassed with N ₂ gas was passed at 5 liter / min. DO was about 20 ppb. The glass electrode and the platinum electrode were put in the tank 38, and the pH and the oxidation-reduction potential were measured. The pH will be in the range of 6-5 and the redox potential will be about-
It was 0.65V. The oxidation-reduction potential is in a more negative direction than in Example 1, and it is considered that a stronger reducing species is generated. One of the reduced species candidates is, for example, H (hydrogen radical).

Next, in the above-mentioned electrolytic cell, Nafion 117 provided in the cathode chamber and the intermediate chamber was removed, and Nafion NR filled in the intermediate chamber was brought into direct contact with the carbon electrode. At this time, the valves 47 and 48, which are the inlet and outlet valves of the intermediate chamber, were closed. Constant current electrolysis was performed at the same flow rate of 1 liter / min and electrolysis current of 0.25 A as in the above electrolysis conditions.
The pH was between 5 and 4, and a more acidic liquid was obtained.

[0035] In the electrolytic cell shown in Example 3 Fig. 1, with a -SO ₂ NHCH ₂ CH ₂ anion-exchange membrane NH ₂ group is attached to the fluororesin as an ion-exchange membrane, at 80 mesh anode and cathode 80 × 60 mm platinum was used. 1 MΩ / c incorporating this electrolytic cell into the apparatus of FIG.
m of pure water was circulated at a flow rate of 1 liter / min, and constant current electrolysis was performed at an electrolysis current of 1.5 A. A glass electrode, a platinum electrode and the tank 2 were put into the tank 2 to measure pH and oxidation-reduction potential. FIG. 8 shows the change over time in pH. As can be seen from the figure,
Reached 10.5 after about 15 minutes. The oxidation-reduction potential became about -1.0V. NaOH is added to pure water to adjust pH1.
When an aqueous solution of 0.5 was prepared, the oxidation-reduction potential was about -0.1.
It was 1V. The oxidation-reduction potential of the electrolytic solution is in a direction lower than -0.1 V, and shows a strong reducing property. Thus, an alkaline reducing electrolyte was obtained without adding a counter ion.

The cleaning effect of this electrolytic solution was confirmed for a printed substrate soldered. One printed board of about 50 × 50 mm was placed in an electrolyte of pH 10 in a tank 2 for 3 hours.
The other printed circuit boards were immersed in pure water having a resistance of 1 MΩ / cm for 30 seconds. After immersion, the surface of each printed circuit board was rinsed with pure water. The amount of ions remaining on the surface of the print substrate was evaluated by measuring the conductivity of the waste liquid that had been washed off. FIG. 9 shows the relationship between the number of times of washing and the conductivity of the waste liquid. In the figure, curve 1 shows the case where the printed board is immersed in pure water, and curve 2 shows the case where the printed board is immersed in the electrolytic solution. As can be seen from the figure, the conductivity of the waste liquid decreases rapidly when immersed in the electrolytic solution. This indicates that the electrolytic solution has a higher cleaning effect than pure water.

Example 4 In the electrolytic cell shown in FIG. 2, platinum having a size of 80 × 60 mm and 80 × 60 mm was used for the anode and the cathode, and Nafion 117 was used as the ion exchange membrane.
160 g of R50 were charged. In this example, Nafion 11
7 between the cathode and the cathode, 100
A mesh net was inserted as a spacer. A glass electrode and a platinum electrode were immersed in a tank in which this electrolytic cell was incorporated into a one-through system shown in FIG. 6, and the pH and the oxidation-reduction potential of the electrolytic solution were measured. Ultrapure water having an electric resistance of 16.5 MΩ / cm was passed at a flow rate of 1 liter / min, and an electrolytic current of 1.
Constant current electrolysis was performed at 5 A. The pH was between 9.5 and 10, and the oxidation-reduction potential was about -0.8V. It has been proved that the insertion of the spacer reduces the amount of H ⁺ ions adsorbed on the surface of the platinum cathode to cause reductive decomposition of H ₂ O.

Example 5 In the electrolytic cell of FIG. 1, -SO ₂ NHC was used for the ion exchange membrane.
An anion exchange membrane having H ₂ CH ₂ NH ₂ groups was used, and platinum of 80 × 60 mm with 80 mesh was used for the anode and the cathode. This electrolytic cell was incorporated in a circulation type apparatus shown in FIG. However, unlike Example 2, the anode chamber was connected to the circulation line. That is, the anode electrolyte was circulated. A glass electrode and a platinum electrode were immersed in the tank.

Pure water having an electric resistance of 1 MΩ / cm was circulated at a flow rate of 1 liter / min, and was subjected to constant current electrolysis at a current of 0.5 A. FIG. 10 shows the change over time in pH. PH after 15 minutes
Reached 4.75. The oxidation-reduction potential is + 0.4V
And an acidic electrolyte solution was obtained.

Example 6 In the electrolytic cell shown in FIG.
Approximately 160 g of Nafion NR-50 was filled in the intermediate chamber using platinum having a mesh size of 80 × 60 mm. In this example, the ion exchange membrane between the anode and Nafion NR-50 was removed, and Nafion 117 was inserted only between the cathode and Nafion NR-50. Example 2
It was incorporated into the device shown in FIG. However, unlike Example 2, the anode chamber was connected to a one-through line. Specifically, the anode chamber is 33 and the cathode chamber is 35
And Further, the valves 48 and 47 at the entrance and exit of the intermediate chamber were closed. Ultra-pure water of 16.5 MΩ / cm was flowed through the electrolytic cell at a flow rate of 1 liter / min in a one-through manner, and subjected to constant current electrolysis at a current of 1.5 A. The glass electrode and the platinum electrode were put in the tank 38, and the pH and the oxidation-reduction potential were measured. The pH dropped to 5-4 and the redox potential was about 0.45V. When the pH is simply adjusted to 5 to 4 using an acid, the oxidation-reduction potential becomes 0.2
０．３0.3V. It can be seen that the potential of the electrolyte is more noble than this potential and is oxidizing. Further, since O ₃ was generated from the electrolytic solution, it is considered that O ₃ contributed to this oxidation-reduction potential.

Example 7 Styrene-based strongly acidic cation exchange resin IR-120B (E
First, concentrated sulfuric acid was added to the ion-exchange group (Na form)
Using -SO₃Na to -SO₃Change to H type
The exchange resin was sufficiently washed with pure water. 100 final washings
ml sampled, and 0.01 mol (M)
10cc of barium aqueous solution was added, but precipitation did not occur.
I couldn't. From this result, it elutes from the ion exchange resin.
SO₄ ^2-The ions are determined to be 0.1 ppm or less.

Take 5 g of ion exchange resin, and add about 1 M
Add 100 cc to Ω / cm pure water and leave for 10 minutes. The supernatant was taken and the pH was measured with a glass electrode. A value of 3.6 was obtained. 0.01 in 40 ml of supernatant
When 0.4 ml of M NaOH aqueous solution was added, the pH of the glass electrode was 6.3. From this result, it can be seen that H ⁺ ions are present in the supernatant. That is, an acidic liquid was obtained without adding a counter ion. By adding 30% H ₂ O ₂ to this, an acid and oxidizing liquid can be obtained without adding a counter ion.

The effect of this liquid was measured by using the finger attached to the glass surface.
The evaluation was made based on the pattern removal speed. 40 ml of the above acidic water
30% H₂O₂1g and 30% H in pure water
₂O ₂1 g was prepared. Gala with fingerprint
Prepare two pieces of glass, immerse them in each solution, and release in a container for about 1 hour.
Was placed. After observing the surface condition for 1 hour,
Fingerprints on the surface of the glass immersed in
One had a fingerprint left. From these results it is acidic and
The effectiveness of the oxidizing liquid is determined.

Example 8 In the electrolytic cell shown in FIG.
A platinum electrode having a size of 80 × 60 mm is used, and a cathode electrode is made of a carbon electrode having carbon fired at about 750 ° C. as in Example 2, and anions are eliminated from Nafion 117 and Nafion 117 as a diaphragm. Both competent Nafion 324 were used in tandem. The intermediate chamber was filled with 170 g of Amberlite 15 (manufactured by Organo Corporation). This electrolytic cell was incorporated in the device shown in FIG.

Ultrapure water is supplied from the ultrapure water producing apparatus 36 shown in FIG. The solution subjected to cathodic electrolysis is stored in a tank 38 via a pipe 39. The overflowed liquid is discharged through the pipe 40. In the intermediate chamber tank 41, H ⁺
In order to supply more ions, a solution in which polyacrylic acid is dissolved at 0.01M is added. The polyacrylic acid itself does not move to the cathode chamber by the cation exchange membrane. Pipe the liquid from the _{N 2} gas cylinder 42 4
4 and bubbling with a bubbler 43. The liquid in which the dissolved oxygen concentration (DO) has been reduced by bubbling is supplied to the intermediate chamber using the piping 46 and the circulation pump 45.

At a flow rate of 1 liter / min, 16.5 MΩ
/ Cm of ultrapure water is allowed to flow in the cathode chamber in one direction. In this state, a constant current analysis at an electrolytic current of 0.25 A was performed. A deaerated aqueous solution of polyacrylic acid was passed through the intermediate chamber at 0.5 L / min. Tank 3
8, a glass electrode and a platinum electrode were inserted, and the pH and the oxidation-reduction potential were measured. The pH dropped to 5-4 and the redox potential was about -0.7V. By placing the polyacrylic acid solution in the intermediate chamber, a stronger acidic liquid was obtained than in Example 2.

[0047]

As described above, according to the present invention,
Anions such as Cl ⁻ , SO ₄ ²⁻ , NO ₃ ⁻ and N
An acidic or alkaline liquid having redox performance can be obtained without using cations such as a ⁺ and K ⁺ .

According to the present invention, the following effects can be obtained.

The acidic and reducing liquid is effective for dissolving and removing an oxide film or rust on a metal surface, and for cleaning a surface while preventing oxidation of a silicon wafer. An even greater advantage is that Cl can promote metal corrosion after cleaning.
^{It is} a trap source for ions or electrons of silicon semiconductors; Since harmful ions such as Na ⁺ and K ⁺ ions do not remain, the amount of pure water or ultrapure water used for final cleaning can be reduced. The acidic oxidizing liquid is effective for decomposing and removing organic substances attached to the surface of a silicon wafer, glass, or the like. Cl remains on the surface, such as with the printed circuit board reducing the liquid alkaline ^- removal rate of such ion is greater than just pure water. When the electrolytic solution is used, the removal rate of the ionic impurities is increased, and the cooling water can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a configuration outline of an electrolytic cell used in the present invention,

FIG. 2 is a diagram showing a schematic configuration of an electrolytic cell used in the present invention;

FIG. 3 is a diagram showing an outline of a configuration of a test apparatus used in Example 1.

FIG. 4 is a diagram showing the results of Example 1.

FIG. 5 is a diagram showing the results of Example 1.

FIG. 6 is a diagram showing a carbon electrode incorporated in the electrolytic cell used in Example 2,

FIG. 7 is a diagram showing an outline of the configuration of a test apparatus used in Example 2.

FIG. 8 is a diagram showing the results of Example 3.

FIG. 9 shows the results of Example 5.

[Description of Signs] 1 ... Ion exchange membrane, 2 ... Cathode electrode, 3 ... Anode electrode,
4 ... electrolyzer, 5 ... into the cathode chamber, 6 ... outlet in the cathode chamber,
7 ... Anode compartment inlet, 8 ... Anode compartment outlet, 9 ... Cathode compartment, 10 ... Anode compartment, 11, 12 ... Ion exchange membrane,
13: cathode electrode, 14: anode electrode, 15: cathode chamber inlet, 16: cathode chamber outlet, 17: anode chamber inlet, 18: anode chamber outlet, 19: intermediate chamber inlet, 20 ...
Intermediate chamber outlet, 21: cathode chamber, 22: anode chamber, 2
3 ... Intermediate chamber, 25 ... Electrolyzer, 26 ... Electrolyzer, 27 ... Cathode, 28 ... Anode, 29 ... Tank, 30 ... Circulation pump, 31 ... Piping, 32 ... Electrolyzer, 33 ... Cathode, 34 ... Intermediate chamber, 35 Anode chamber, # 6 Ultrapure water production equipment, 37 Pump, 38 Tank, 39 Pipe, 4
0: Waste liquid pipe, 41: Degassing tank, 42: Nitrogen cylinder, 43: Bubbler, 44: Nitrogen gas pipe, 45: Pump, 46: Pipe, 47: Intermediate chamber inlet, 48: Intermediate chamber outlet.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshimasa Hashimoto 1-1-13-1401 Nakamura, Nerima-ku, Tokyo F-term (Reference) 4D050 AB11 BB02 BD04 CA10 4D061 DA03 DB07 EA02 EB04 EB13 EB28 EB29 EB30 FAEB EB31 EB35 FA08

Claims (8)

[Claims] 1. A washing water in which the concentration of hydrogen (H ⁺ ions) is made larger than that of anions by electrolysis of pure water. Wherein the electrolysis of pure water, hydroxyl compared to cation concentration (OH ^- ions) washing water that excessive concentration. 3. The cleaning water according to claim 1, wherein the redox substance is made to coexist in water having an excess of H ⁺ ions as compared with the anion concentration. 4. The cleaning water according to claim 1, wherein an OH ^- ion is present in excess of cation concentration in the water and a redox substance coexists. 5. A method for producing H ⁺ ions and a redox substance in cleaning water without adding an anion by electrolyzing pure water or ultrapure water. 6. A method for producing OH ^- ions and a redox substance in washing water without adding cations by electrolyzing pure water or ultrapure water. 7. The method of claim 5, the cation exchange membrane and a cation exchange resin as a diaphragm structure, a carbon obtained by firing an organic material at 600 to 800 ° C. as the cathode electrode using an electrode held on the surface, H ⁺ A method of producing ions and hydrogen atoms, hydrogen molecules or hydrogen peroxide. 8. The method according to claim 5, wherein a cation exchange membrane and a cation exchange resin are used as a membrane structure, and platinum or β-type lead oxide is used as an anode electrode to generate H ⁺ , ozone, and oxygen molecules.