A new solution has been developed thanks to PAC-G to characterise 3D integration systems, which aims to make devices smaller. STMicroelectronics has worked with a team of researchers from the CEA-Leti and the ESRF - The European Synchrotron, using synchrotron tomographies contrast. Computed tomography techniques offer good information about the voids present in the pillars and, in the case of synchrotron radiation, also about the intermetallic shapes.