ISTFA 2025: Investigating Subsurface Defects: 3D EBAC Mapping with Varying Beam Energies

Abstract: Electron Beam Absorbed Current (EBAC) imaging has become an indispensable technique for isolating and analyzing electrical failures in advanced semiconductor devices. This work presents the effects of varying electron beam energies on EBAC image quality and subsurface sensitivity. By acquiring EBAC images at multiple accelerating voltages, we explore how beam energy influences current collection efficiency, resolution, and the depth of electrical interaction within complex interconnect stacks. Lower beam energies emphasize surface-level features and near-surface opens, while higher energies enable visualization of deeper conductive layers and buried defects. A novel 3D reconstruction methodology is introduced, integrating multi-energy EBAC datasets to spatially resolve conductive pathways in three dimensions. This approach enhances defect localization accuracy in advanced nodes and supports root cause analysis for complex failure mechanisms such as via voids, leakage paths, and metal line breaks. The results