Integrating thermocouple sensors into 3D ICs

In this paper, we present a novel architecture for embedding bi-metallic thermocouple based temperature sensors into 3D IC stacks. To the best of our knowledge this is the first work addressing this specific integration problem. Our architecture uses dedicated vias to thermally couple sensors in the metal layer with the hotspots to be monitored in the active layer throughout the multi-stack structures. We propose a low cost solution by leveraging a fraction of existing thermal TSVs for this purpose. Through thermal modeling and simulation using a state-of-the-art tool (FloTHERM), we demonstrate that we can achieve high accuracy (less than 1°C error) in temperature tracking while still maintaining the effectiveness of the thermal TSVs in heat management (conforming to a fixed peak temperature threshold of 95°C).