Hi Yilei, I don't think it will work, particularly if the oxide is thermally grown. Better to use LPCVD silicon nitride. -Mike >>> ylzhang@iastate.edu 6/22/2004 1:46:11 PM >>> Hello: I have a silicon wafer (around 800um thick) with 300nm SiO2 on one side. and i want to etch some small squares (2cm*1.5cm) through silicon without breaking the Sio2 layer above those squares. Is it possible? I am worrying about the thickness of the SiO2 layer and its intrinsic stress. Will increasing the thickness to 500nm be helpful? thanks. Regards, Yilei Zhang _______________________________________________ MEMS-talk@memsnet.org mailing list: to unsubscribe or change your list options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk Hosted by the MEMS Exchange, providers of MEMS processing services. Visit us at http://www.memsnet.org/