Hi all i am trying to use TMAH+Silicic Acid+ Ammounium persulfate solution for protecting Al on Si. But i am not able to dissolve Silicic acid in 5% TMAH Solution. i have tried at 80 C nd 120 C for about one hour without any result. can anybody help me in this matter. Mukesh Kumar Advanced materials and Devices group TASC-INFM Basovizza, S.S. 14 Km 163.5 34012 Trieste ITALY email:- kumarm@tasc.infm.it phone:- +39 040 3756438