A cross-layer design exploration of charge-recycled power-delivery in many-layer 3D-IC

3D-IC technology brings both the opportunities to continue the historical trend of integration-level scaling and the challenges to deliver power reliably and efficiently. Voltage-stacking (V-S), a charge-recycled power delivery scheme that connects the different layers´ supply/ground nets into a series stack, provides a scalable solution to the 3D-IC power delivery wall. While prior work has extensively discussed the implementations of V-S at circuit-level, a cross-layer study that examines its system-level implications is missing. In this paper, we start with a circuit implementation of a charge-recycled voltage regulator and build an architecture-level model to study the costs and benefits of utilizing V-S in 3D-IC. Our study shows that by significantly improving the EM-lifetime of C4 and TSV array (e.g., up to 5x) while only marginally increasing the average-case voltage noise (e.g., 0.75% Vdd IR drop), V-S provides a scalable solution for many-layer 3D-IC´s power delivery challenge.