Panel Level Packaging for Component Integration of an Energy Harvesting System

Within the European funded project smart-MEMPHIS the goal was to tackle the main challenge for all smart devices – self-powering. The project was aimed to design, manufacture and test a miniaturized autonomous energy supply based on harvesting vibrational energy with piezo-MEMS energy harvesters. Cost effective packaging was needed for 3D system integration of a MEMS-based multi-axis energy harvester, an ultra-low-power ASIC to manage the variations of the frequency and harvested power, and a miniaturized energy storing supercapacitor. Miniaturization was another key demand as target applications were a leadless pacemaker and a wireless sensor network for structural health monitoring. Panel Level Packaging (PLP) was selected as packaging technology for the harvester components. A basic study on the embedding of piezo-MEMS harvester has been performed as well as the development and proof of concept of a new PLP based supercapacitor housing. For the power management unit an ASIC together with two capacitors have been integrated by Fan-out Panel Level Packaging (FOPLP). Material selection and process development was first done on wafer level size and then transferred to large area 457x305 mm2 panel size. Main focus was here to find a suitable material combination and process parameters for the embedding of SMD capacitors together with bare dies in a fan-out panel level package. A technology study has been performed to analyze the influence of SMD component size and pitch, thermal release tape and epoxy molding compound type during compression molding. Results have used to finally select materials for prototype built. Reliability testing have been performed to prove the overall concept and material selection for PLP.