Local material removal by focused ion beam milling and etching

Focused ion beams (FIB) have drawn considerable interest as a tool for micromachining in the sub-micrometer regime with major applications in failure analysis and circuit repair. With shrinking dimensions, the demands on the precision of FIB-machining are increasing. Tn this paper, focused ion beam enhanced etching of silicon has been investigated using iodine as an etchant which leads to an increase in the material removal rate of silicon by a factor of up to 30 compared to sputter erosion. The influence of current density, dwell time, and loop time on the removal rate will be discussed and compared to model calculations. By secondary electron microscopy, the maximum slope of the generated structures has been determined. Finally, the application of this technique to the formation of thin lamellas for TEM inspection will be shown.