edfas.org 19 ELECTRONIC DEVICE FAILURE ANALYSIS | VOLUME 27 NO. 4 which, based on these findings, leads to substantial and irreversible degradation. By contrast, the SMARPROBE system allows automated transitions between transistors based on CAD layout data, as shown in Fig. 7. After initial alignment, only one or two additional SEM images per transistor are needed to verify correct probe placement, reducing the total imaging time for all six transistors to less than two seconds. Even under these minimal exposure conditions, no degradation was detected, underscoring the robustness of the semi-blind approach for highly beam-sensitive devices such as FETs in FD-SOI nodes. CONCLUSION The presented study demonstrates that electron beaminduced degradation constitutes a critical limitation for SEM-based nanoprobing of advanced semiconductor devices, particularly for highly beam-sensitive structures such as FETs in 22 nm FD-SOI technology. It was shown that continuous SEM exposure at both 100 eV and 200 eV beam energies resulted in significant, non-reversible threshold voltage shifts. It was shown that 100 eV beam energy severely slows the degradation process, however, it also comes with a reduction in image quality and increase in image acquisition time, which reduce their practical advantage, especially when manual probe placement requires extended SEM imaging. The semi-blind probe positioning approach was shown to effectively avoid beam-induced degradation, by reducing the number of required SEM images by around two orders of magnitude, enabling reliable probe placement with minimal cumulative beam exposure. Under these conditions, no measurable degradation at 200 eV was observed when comparing electrical characteristics to electron-beam-free AFP benchmarks, even after probing multiple transistors in a 6T SRAM cell. This highlights that minimizing the number of images represents an effective strategy for preserving device integrity during nanoprobing, even at beam energies of 200 eV. ACKNOWLEDGMENTS The authors thank Pascal Limbecker and Andreas Bautz from GlobalFoundries for the technical discussions and for providing the FD-SOI sample and AFP reference measurement. REFERENCES 1. T. Ishitani and M. Sato: “Evaluation of Both Image Resolution and Contrast-to-noise Ratio in Scanning Electron Microscopy,” Journal of Electron Microscopy, 2007, 56(4), p. 145-151. Fig. 7 SEM images within the SMARPROBE user interface during the automated probing workflow of a 6T SRAM cell of the FD-SOI technology.
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