"Shallow Trench Isolation" Structures - Sample Preparation for TEM

The cross-sectional preparation of structured semiconductor materials requires a very thorough mechanical preparation. In doing this, it must be ensured that the structure of interest should be located as close to the centre of the sample as possible. As the sample will be ion milled from both sides, a specific preparation of the structure is necessary in most cases, which means that you must thin these structures from both sides.

With three-dimensional repetitive structures (test structures), as mostly used in micro-electronics, this is often no problem. If, however, you want to prepare individual structures with very small dimensions, the observation possibilities of conventional ion beam milling systems are insufficent for carrying out a target preparation. In that case one need a FIB system.

In the case of "shallow trench isolation" structures, the repetitive structures have already been brought to the centre of the cross-sectional sample by the mechanical pre-preparation.