Volumetric nondestructive metrology for 3D semiconductor packaging: A review

Three-dimensional (3D) semiconductor packaging has the potential to overcome Moore's Law for future inte-grated circuits (ICs), but the inspection and testing of 3D ICs to ensure quality, reliability, and yield remain a major obstacle. Volumetric nondestructive testing (VNDT) possesses unique advantages for this purpose. The paper surveys the principles of major VNDT techniques, including X-ray microscopy, scanning acoustic micro-scopy, and terahertz microscopy, and their technological advances towards 3D packaging applications. Mean-while, the state-of-the-art developments in VNDT for failure analysis and fault isolation in 3D ICs are summarized, which cover not only direct adoption of VNDT for various applications, but also employment of machine learning (ML) and artificial intelligence (AI) to complement VNDT. More importantly, a critical analysis is provided to discuss the remaining challenges for 3D package inspection, and thus the research opportunities are identified for VNDT techniques, as well as their integration with ML/AI for addressing the future needs.