MUF Technology Development for SiP Module

In this study, we developed the molded underfill (MUF) technology for system in package (SiP) module with fine pitch flip chip in RF application, in which two flip chips, LC filter, and additional passive components are integrated side-by-side. This study covered not only MUF reliability performance but also MUF design study focused on minimizing voids between flip chip bumps in the SiP module. The investigation comprises several aspects: A design study that present a printed circuit board (PCB) and epoxy molding compound (EMC) selection approach, air vent design of cavity vacuum molding, and results of void free from Design of Experiment (DOE) of several SiP module layouts. In the end, Scanning Acoustic Tomography (SAT) result of void, moisture sensitivity test, thermal cycle test and pressure cooker test had also been carried out for reliability evaluation. The test result shows that the optimized SiP module with fine flip pitch has a good reliability performance.