Patent ID: 10032623

Abstract:
A cleaning method including a persulphuric acid producing step of causing a cleaning sulfuric acid solution to travel into an electrolyzing section and to circulate therethrough to produce persulphuric acid having a predetermined concentration by electrolysis in the electrolyzing section, a solution mixing step of mixing the sulfuric acid solution containing the persulphuric acid produced in the persulphuric acid producing step with a halide solution containing one or more types of halide ion without causing the solutions to travel into the electrolyzing section to produce a mixed solution having a post-mixture concentration of oxidant including the persulphuric acid that ranges from 0.001 to 2 mol/L, a heating step of heating the mixed solution, and a cleaning step of cleaning a semiconductor substrate by transporting the heated mixed solution to cause the heated mixed solution to come into contact with the semiconductor substrate.