Production device for pH/redox potential-adjusted water
A production device for pH/redox potential-adjusted water ( 1 ) of the present invention includes a platinum group metal-supporting resin column ( 3 ) that is provided in a supply line ( 2 ) of ultrapure water (W) and a pH adjuster tank ( 4 ) and a redox potential adjuster tank ( 5 ) that are provided downstream the platinum group metal-supporting resin column ( 3 ). A membrane-type degassing device ( 6 ) is provided downstream them, and a gas-dissolving membrane ( 7 ) is disposed downstream the membrane-type degassing device ( 6 ). A cleaning water quality monitoring mechanism including a pH meter, an ORP meter, and an inert gas concentration measuring means is provided downstream the gas-dissolving membrane ( 7 ) of the supply line ( 2 ). The cleaning water quality monitoring mechanism is connected to a control means (not illustrated). The control means is capable of controlling a pump ( 4 B) of the pH adjuster tank ( 4 ), a pump ( 5 B) of the redox potential adjuster tank ( 5 ), and the gas-dissolving membrane ( 7 ) based on the measurement values of the cleaning water quality monitoring mechanism. With such a configuration, the present invention can suppress dissolution of metals to a minimum level in a rinsing step for the surfaces of wafers on which chromium group elements are exposed.
1 . A production device for adjusted water having pH and redox potential that produces adjusted water having a desired pH and a desired redox potential by adding a pH adjuster and a redox potential adjuster to ultrapure water, comprising:
a hydrogen peroxide removal mechanism provided in an ultrapure water supply line;
a pH adjuster addition mechanism and a redox potential adjuster addition mechanism that are provided downstream of the hydrogen peroxide removal mechanism;
a degassing mechanism provided downstream of the pH adjuster addition mechanism and/or the redox potential adjuster addition mechanism; and
an inert gas dissolution mechanism provided downstream of the degassing mechanism, wherein the produced adjusted water having pH and redox potential has a pH of 0 to 5, a redox potential of −0.4 to +0.4 V, a dissolved oxygen concentration of 50 ppb or less, and a hydrogen peroxide concentration of 1000 ppm or less, and the production device further comprising:
a water quality monitoring mechanism configured for monitoring the pH, redox potential, and inert gas concentration of the adjusted water to determine whether or not the adjusted water has the desired pH and the desired redox potential; and
a control device capable of stabilized control of the inert gas dissolution mechanism, the pH adjuster addition mechanism, and the redox potential adjuster addition mechanism based on measurements from the water quality monitoring mechanism so that the inert gas dissolution mechanism adjusts the inert gas concentration, the pH adjuster addition mechanism adjusts the pH, and the redox potential adjuster addition mechanism adjusts the redox potential,
wherein the adjusted water having pH and redox potential produced is suitable for cleaning a semiconductor material on which molybdenum is partially or entirely exposed.
2 . The production device for adjusted water having pH and redox potential according to claim 1 , wherein the pH adjuster is one or more selected from the group consisting of hydrochloric acid, nitric acid, acetic acid, and CO 2 gas, the redox potential adjuster is one or more selected from the group consisting of oxalic acid, hydrogen sulfide, potassium iodide, and hydrogen gas, and the inert gas is one or more selected from the group consisting of nitrogen, argon, and helium.
3 . The production device for adjusted water having pH and redox potential according to claim 1 , wherein the pH adjuster or the redox potential adjuster is a liquid, and the pH adjuster addition mechanism or the redox potential adjuster addition mechanism includes a pump that supplies the liquid pH adjuster or redox potential adjuster or a pressurizing and pushing-out device configured to use an inert gas to push out and supply the liquid pH adjuster or redox potential adjuster from a tank that stores the liquid pH adjuster or redox potential adjuster.
4 . The production device for adjusted water having pH and redox potential according to claim 1 , wherein the pH adjuster or the redox potential adjuster is a gas, and the pH adjuster addition mechanism or the redox potential adjuster addition mechanism is a gas dissolution device comprising a gas-permeable membrane module or a direct gas-liquid contactor.
5 . The production device for adjusted water having pH and redox potential according to claim 1 , wherein the inert gas dissolution mechanism is a gas dissolution device comprising a gas-permeable membrane module or a direct gas-liquid contactor.