Low-temperature 3D integration processes for advanced sensor systems
Paper presented at nanoFIS 2017, 3rd International Conference on Functional Integrated nano Systems, 22 - 24 November 2017, Graz
One of the main drivers of 3D heterogeneous integration is certainly sensor integration. The system integration of sensors with ICs, passive components and even energy harvesting systems is becoming more and more important especially for the high growth market area of distributed wireless sensor systems which will constitute the key connected hardware infrastructure of the Internet-of-Things (IoT). The application IoT is predicted as a third wave of MEMS proliferations, after Automotive and Mobile Phones. A subset of IoT are smart objects showing local intelligence and awareness. We are in the phase of rapidly growing markets and increasing competition and we must reach for cost reduction, standardization and increasing functionality and performance. A corresponding key is simplification of processes and explicitly regarding the fabrication of device stacks by wafer bonding. The challenge to realize such complex 3D systems mainly consists on the heterogeneity of the components typically at least one sensor, one IC for data processing and one IC for data transmission. In this field the new low temperature processes are the key to realize robust heterogeneous sensor system with high performance and reliability. Relevant bonding schemes, including oxide-oxide bond and variants of metal bond technologies - as thermocompression bonding, solid-liquid-interdiffusion (EMFT) and DBI® (XPERI) - will be compared.