Reliability Study of WLP for SAW Filter with Through Film Vias Using Laser Drilling technology

This paper reports the wafer level surface acoustic wave (SAW) filter package design, fabrication technology, and reliability aspects. The key process including cavity wall (CV) dam fabricating, non-photosensitive dry film lamination, redistribution layer (RDL), and ball-grid array formation are developed. Additionally, a computer research using the finite element model (FEM) has been done to examine the evolution of wafer warpage. The results match the experiment well. After the fabrication process optimization, the reliability of the packages is characterized by pre-conditional level 3 (Pre Con-L3) and unbiased-highly accelerated stress (uHAST), and the results show a good package level reliability. This work offers insight work for the SAW filter package design.