Si interposer with multiple cavities for 3D stacked fan-out package

In this paper, a Si interposer with multiple cavities for 3D stacked fan-out package is presented. It's made up of multiple cavities and electrical path through both sides made of metal conducting lines on the sidewall of cavity and silicon pillars beneath the cavity, which avoids the processing of copper TSVs on Si interposer and is suitable for three-dimensional(3D) stacking. To verify this technology concept, a process for the Si interposer is designed. Test prototypes is fabricated and electrical path through both sides of Si substrate made of linked isolated Si pillar by Al rewiring lines is characterized in term of resistance test. Meanwhile, the finite element analysis model of Si interposer is established where Siliconre/flow glass is taken as elastic material and metal interconnection as elastro-plastic material to investigate the thermal stress/strain during the thermal cycling experiments.