Hi everyone, In DRIE using ICP plasma source, After glow discharge, SF6 will be diassosciated . There are radicals(F atom), neutrals(SF6 ? ), electrons, positive ion(SF5+ or SFx+), negetive ion(F-). 1) How to transport the F atom to the bottom of the trench without substrate bias help? By positive ion's (SF5+) collision? 2) Which is the main etchant, The radicals(F atom) or positive ions (SF5+)? 3) Negtive ions (F- ) cannot reach the bottom of trench, is it a waste? 4) How does the ion/neutral ratio influence the etching if the ratical (F atom) is the main etchant? references or suggestions will be appreciated Yan Xin -Pen-Tung Sah MEMS Research Center, -Xiamen University, CHINA XMU HOME: http://memsc.xmu.edu.cn/mems_renchaiduiwu/XuYuan_Chen-Group/index_1.html