| 摘要 |
PROBLEM TO BE SOLVED: To stably perform washing without causing the decrease in washing force and the excessive consumption of chemical liquid in a washing method using the mixed liquid of fluoric acid and hydrogen peroxide water as washing liquid. SOLUTION: While the concentration of fluoric acid and that of hydrogen peroxide water of the mixed liquid of fluoric acid and the hydrogen peroxide water that are used for washing are measured and verified to be first specific values (a) and (b) or larger, the liquid temperature is measured, the mixed liquid is cooled so that the reference temperature or less can be set when the liquid temperature is higher than a reference temperature (c) for washing so that the reference temperature or less can be retained. Then, during washing, washing is continued when the concentration of fluoric acid and that of hydrogen peroxide water are equal to second specific values (d) and (e), respectively, and washing is stopped when they are equal to or less than the second specific values (d) and (e), respectively. |
