Die Shift on Chip First Panel Level Fan-Out Packaging

Die shift is one of the most critical issues facing by the chip first and face down fan-out process. Unlike factors such as CTE mismatch that induce theoretically predicable die shift, unexpected offset usually happens which makes chip position compensation a big challenge. This paper analysis related factors contributing to die shift in the sight of die bonder condition, compound property such as shrinkage, HRT (Heat Release Tape), and mold flow. It also presents experimental data on how the factor affect die shift and come to the summary that both smaller positive mold compound shrinkage and rougher chip surface will do help on the chip position. Improving the die shift issue involves aspects including enhancing material properties encompassing thermal and chemical stability, equipment precision and process/product design. Furthermore, process innovation is suggested to mitigate the impact of material inherent characteristics on die shift.