The influence of the redeposition effect on the focused ion beam 3D microma
chining process of silicon is discussed. Milling of some typical patterns i
n which redeposition is serious has been carried out. Experimental results
are analysed in combination with a theoretical mode. It can be seen from th
e analysis that the order of recycle-milling is very important for 3D micro
fabrication owing to redeposition during the process. In addition, the para
meters of beam current, ion beam spot size, etc. are also key factors in th
e process. A groove and dome shape will be formed at the root of the sidewa
ll and the bottom of the pattern, respectively, because of the ion sputteri
ng yield variation and sidewall redeposition. Finally, avoidance methods ar
e suggested as a result of the analysis.