Through silicon via technology — processes and reliability for wafer-level 3D system integration

3D integration is a rapidly growing topic in the semiconductor industry that encompasses different types of technologies. The paper addresses one of the most promising technologies which uses through silicon vias (TSV) for interconnecting stacked devices on wafer-level to perform high density interconnects with a good electrical performance at the smallest form factor for 3D architectures. Fraunhofer IZM developed a post frontend 3D integration process, the so- called ICV-SLID technology based on metal bonding using solid-liquid-interdiffusion (SLID) soldering. The SLID metal system provides the mechanical and the electrical connection, both in one single step. The ICV-SLID fabrication process is well suited for the cost-effective production of both, high- performance applications (e.g. 3D microprocessor) and highly miniaturized multi-functional systems. The latter preferably in combination with wafer-level die stacking, as e.g. Thin Chip Integration (TCI) or SnAg-microbump technologies. The fabrication of distributed wireless sensor systems (e. g. e-CUBES^reg) is a typical example for the need of such mixed approaches.