Evaluation of warpage of FOWLP considering the viscoelastic and viscoplastic properties of Epoxy Molding Compound

Fan-Out Wafer Level Packaging (FOWLP) use is growing in electronics driven by high-density and low profile needs from mobile communications. This kind of packaging is also interesting for high frequencies and high-performance applications offering shorter interconnect paths, resulting in fewer parasitic signals and less delay. Regarding manufacturing processes, warpage control and die shift are key technical challenges. Regarding, the reliability of this packaging, due to the reduced distance between semiconductor and the printed circuit board PCB – just few microns of the RDL circuit and the fine-pitch solder joints, warpage control is important to ensure thermo-cycling reliability. In this paper, we will present a modelling methodology for mechanical behaviour of epoxy molding compound (EMC) using viscoelastic and viscoplastic properties. Those models are important for simulations of warpage at wafer and component levels.