Thank you for the response Leo. I am actually trying not to use a silicon dioxide layer underneath. I know CF4 plasma etches nitride and as far as I know the etch rate of silicon is very low. Any other thoughts are appreciated. Deepa On Tue, Oct 28, 2008 at 2:38 PM, Xiaoguang Liuwrote: > Hi > If you could afford to have SiO2 underneath the SiNx, you could dry > etch to the SiO2 layer and remove the remaining SiO2 by BOE. > Best > Leo