Experimental study of three-dimensional microfabrication by focused ion beam technology

Combined with experimental milling, three-dimensional (3D) microfabrication by focused ion beam (FIB) technology has been studied. Rules among limiting aperture size, dwell time, retrace time, tail of Gaussian distribution, etc., have been analyzed in terms of experimental results. Some phenomena are explained from the theoretical point of view. In addition, influence of redeposition for the sidewall root of microstructure in the process of milling is analyzed, and the avoidance methods are used in the meantime. It was proved by experiment that beam current (representing ion beam energy) and beam spot size play an important role in the etching process. Nonlinear variation of these parameters led to the broadening of edge periphery and redeposition at the root of the sidewall. On the other hand, milling order is vital for the 3D microfabrication result by FIB sputtering due to the redeposition effect and profile broadening effect. (C) 2000 American Institute of Physics. [S0034-6748(00)65302-9].