Power distribution in TSV-based 3-D processor-memory stacks

Three primary techniques for manufacturing through silicon vias (TSVs), via-first, via-middle, and via-last, have been analyzed and compared to distribute power in a 3-D processor-memory system with nine planes. Due to distinct fabrication techniques, these TSV technologies require significantly different design constraints, as investigated in this paper. A valid design space that satisfies the peak power supply noise while minimizing area overhead is identified for each technology. It is demonstrated that the area overhead of a 3-D power distribution network with via-first TSVs is approximately 9% as compared to less than 2% in via-middle and via-last technologies. Despite this drawback, a via-first based power network is typically overdamped and the issue of resonance is alleviated. A via-last based power network, however, exhibits a relatively low damping factor and the peak noise is highly sensitive to the number of TSVs and decoupling capacitance.