Laboratory X-Ray-Assisted Device Alteration for Fault Isolation and Post-Silicon Debug

Increasing 3D complexities in modern chipsets necessitate new approaches to fault isolation and post-silicon debug. Recent innovations, including backside power delivery networks and multi-die stacking, impede traditional optical techniques, such as laser-assisted device alteration (LADA). X-rays are a natural choice for high precision active circuit perturbation below complex material stacks, but their utility for fault isolation and debug use cases is unknown. Uncertainties include the achievable magnitude of circuit perturbation, the repeatability and linearity of the response, and methodologies for use of an effect which has persistence, impacting circuit behaviors long after the x-ray is turned off. To explore the utility of x-rays for LADA-like work, we have developed a first-of-a-kind x-ray-assisted device alteration (XADA) tool, with an industry-leading spot size and flux density, capable of interfacing with modern integrated circuit test equipment. We demonstrate for the first time the use of XADA for real fault isolation and post-silicon debug cases.