To cater complex topography sensors and circuit chips for smart lifestyle applications using Internet of Things (IoT), we develop a novel efficient double-self-assembly packaging approach by 3D/2.5D heterogeneous integration. This technology is able to integrate various kinds of processed chips, especially with uneven surface and bottom topography. With liquid surface tension, complex topography chips can be handled and self-aligned on precise locations. Double-self-assembly approach demonstrates temporary bonding on carrier wafer and self-aligned permanent bonding in a pressure sensing system packaging. The optimized volume of liquid to use on various complex topography shapes and areas are investigated, while Cu/In low temperature metal bonding and self-assembly approach for high I/O density and low bonding resistance are demonstrated. Excellent electrical characteristics and mechanical strength of show the feasibility of the double-self-assembly approach on complex topography surface chips packaging applications.