| 摘要 |
PURPOSE: To suppress the adsorption of Al from a cleaning solution while enhancing the cleaning effect by blending fluoride ions exceeding a specific value with the alkaline cleaning solution. CONSTITUTION: A fluoride ions are normally added as hydrofluoric acid of fluoride although it may be added in any state. When the hydrofluoric acid is added, normally used as a water solution of 1-80wt.%, but as a fluoride, normally added as a fluoride or ammonium fluoride of organic alkali. At this time, the fluoride ion concentration in the whole solution of cleaning composition shall exceed 0.15mol/l preferably exceeding 0.20mol/l at the upper limit of 2.0mol/l. If the added amount does not exceed the lower limit, both sticking and removing effects will become insufficient. Furthermore, even if the added amount exceeds the upper limit, any exceptional effect can not be expected. |
