Drop impact reliability study of high density fan-out wafer level package

Abstract

RDL first FOWLP with the advantages reducing die shift and wafer level warpage during the fabrication process has been developed. The drop impact reliability for the large size (20 mm×20 mm) RDL first FOWLP is one major concern for the mobile applications. Under drop test loading, crack and delamination failures may happen to the dielectrics layer and solder joints. In this paper, reliability of 20 mm×20 mm RDL fist FOWLP was investigated by the drop impact test and dynamic simulation. The drop impact tests under the loading of 1500 g/0.5 ms were conducted for the RDL fist FOWLP. The drop impact reliability of RDL first FOWLP was validated by the drop impact tests. The failure analysis by doing the cross section and SEM observation was conducted to initial failure sample in order to find out the failure mechanisms. The stress behavior of the solder joints and RDL were investigated by the dynamic drop impact simulation. The effects of the delamination on the stress level on the dielectrics layer under the solder joints was identified by the simulation.