3D ICs: An opportunity for fully-integrated, dense and efficient power supplies

With 3D technologies, the in-package solution allows integrated, efficient and granular power supplies to be designed for multi-core processors. As the converter design obtains few benefits from the scaling, 3DIC allows the best technology to be chosen i.e. one which suits the DC-DC converter design. This paper evaluates the achievable power efficiency between on-die and in-package converters using a combination of active (28 and 65nm CMOS nodes) and passive (poly, MIM, vertical capacitor) layers. Based on the same load power consumption, on-die and in-package switched capacitor converters achieve 65% and 78% efficiency, respectively, in a 1mm² silicon area. An additional high density capacitance layer (100nF/mm²) improves efficiency by more than 20 points in 65nm for the same surface which emphasizes the need for dedicated technology for better power management integration. This paper shows that in-package power management is a key alternative for fully-integrated, dense and efficient power supplies.