Method for producing electrolyzed water

• US 5,762,779 A
• Filed: 06/07/1995
• Issued: 06/09/1998
• Est. Priority Date: 03/25/1994
• Status: Expired due to Fees

• Current Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Original Assignee: NEC Corporation
• Inventors: Shiramizu, Yoshimi, Hamano, Haruto, Aoki, Hidemitsu, Nakamori, Masaharu, Seo, Hirofumi
• Primary Examiner(s): Phasge, Arun S.
• Application Number:
  US08/474,910
• Time in Patent Office: 1,098 Days
• Field of Search: 205/742, 205/743, 205/746, 134/2, 134/3
• US Class Current: 205/746
• CPC Class Codes: C02F 1/36 ultrasonic vibrations
• CPC Class Codes: C02F 1/38 by centrifugal separation
• CPC Class Codes: C02F 1/4618 for producing "ionised" acidic or basic water
• CPC Class Codes: C02F 1/48 with magnetic or electric fields C02F1/46 takes precedence
• CPC Class Codes: C02F 2001/46123 Movable electrodes
• CPC Class Codes: C02F 2001/46133 characterised by the material
• CPC Class Codes: C02F 2103/04 for obtaining ultra-pure water
• CPC Class Codes: C02F 2201/4611 Fluid flow
• CPC Class Codes: C02F 2201/46115 Electrolytic cell with membranes or diaphragms
• CPC Class Codes: C02F 2201/46125 Electrical variables
• CPC Class Codes: C02F 2201/46155 Heating or cooling
• CPC Class Codes: C02F 2201/4618 Supplying or removing reactants or electrolyte
• CPC Class Codes: C02F 2201/4619 Supplying gas to the electrolyte gas diffusion electrodes C02F2001/46166
• CPC Class Codes: C02F 2209/02 Temperature
• CPC Class Codes: C02F 2209/04 Oxidation reduction potential [ORP]
• CPC Class Codes: C02F 2209/05 Conductivity or salinity
• CPC Class Codes: C02F 2209/06 pH
• CPC Class Codes: C02F 2301/066 Overpressure, high pressure
• CPC Class Codes: H01L 21/02052 Wet cleaning only H01L21/02085 takes precedence

Abstract

The method for producing electrolyzed water includes the step of applying a voltage to electrodes disposed in an electrolytic cell containing therein pure water including electrolyte therein. A strength of an electric field generated by applying a voltage to the electrodes is controlled to be variable by means of various techniques. The method makes it possible to produce electrolyzed water with a smaller amount of energy than prior methods.

Claims

1. A method for producing electrolyzed water in a process for treating a semiconductor wafer with electrolyzed water, comprising the steps of:

(a) adding an electrolyte into pure water purified through an ion exchanger to produce pure water containing an electrolyte;

(b) producing electrolyzed water by applying a voltage to electrodes disposed in an electrolytic cell containing pure water and electrolyte therein;

(c) controlling the temperature of said pure water during the step of producing electrolyzed water by applying heating means to the outside of said electrolytic cell to maintain said pure water at a temperature in the range of 20°

-70°

C.; and

(d) applying said electrolyzed water to the semiconductor wafer.

2. The method as recited in claim 1, wherein said temperature of said pure water is controlled to be in the range of 20 to 70 degrees centigrade.

3. The method as recited on claim 1, wherein said electrolyzed water is anodic electrolyzed water.

4. The method as recited in claim 1, wherein said electrolyzed water is cathodic electrolyzed water.

5. The method as recited in claim 1, wherein said electrolyzed water is a mixture of anodic and cathodic electrolyzed water.

6. The method as recited in claim 1, wherein said temperature is more than 35°

C. and less than or equal to 70°

C.

7. The method as recited in claim 1, wherein said electrolyte is ammonium chloride.

8. The method as recited in claim 1, wherein an amount of said electrolyte added to said pure water is not more than 20 mM.

9. The method as recited in claim 1, wherein an amount of said electrolyte added to said pure water is not more than 80 mM.

10. A method for producing electrolyzed water in a process for treating a semiconductor wafer with electrolyzed water, comprising the steps of:

(a) adding an electrolyte into pure water purified through an ion exchanger to produce pure water containing an electrolyte;

(b) producing electrolyzed water by applying a voltage to electrodes disposed in an electrolytic cell containing pure water and electrolyte therein;

(c) controlling the temperature of said pure water during the step of producing electrolyzed water by applying heating means to the outside of said electrolytic cell to maintain said pure water at a temperature high enough to decompose a water cluster and to volatilize oxygen gas and hydrogen gas from said electrolyte and low enough to prevent an oxidizing material and a reducing material produced at said electrodes to be lost by volatilization, said heating means not in direct contact with said pure water; and

(d) applying said electrolyzed water to the semiconductor wafer.

11. The method as recited in claim 10, wherein said temperature is more than 35°

C. and less than or equal to 70°

C.