Influence of the redeposition effect for focused ion beam 3D micromachining in silicon

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.