Development of three-dimensional microanalysis using ion and electron dual-focused beams

The failure analysis of electronic devices and deduction of the emission origins of dust particles in clean processes or in urban air require a precise three-dimensional (3D) microanalysis method. The most indispensable demand for such 3D microanalysis is the applicability to samples with arbitrary shapes and heterogeneity. We are developing a novel 3D microanalysis method which will satisfy these requirements. Our method employs the combination of micro-cross-sectioning of a sample using a Ga focused ion beam (Ga FIB) and Auger mapping of the cross section using an electron beam (EB). On the basis of this concept, we constructed an ion and electron dual-focused beam apparatus. The Ga MB and EB are perpendicularly directed to a sample to define simply the 3D coordinates from the steering of the two beams. Preliminary experiments on the non-element specific 3D imaging of an IC using an EB-induced sample current signal showed a favorable result concerning the reproducibility of the 3D structure within the analysis volume. Furthermore, the contamination of the analytical surface (cross section) due to primary Ga implantation and the redeposition of sputtered materials were found to be greatly reduced in our cross-sectioning method.