Chip Last Fan-out Packaging for Millimeter Wave Application

Traditional FOWLP (fan out wafer level package) requires relative expensive semiconductor equipment to form RDL layers. On the other hand, fan out chip last package (FOCLP) uses low cost substrate and packaging equipment to produce essentially same final package structure. As transmission lines and transitions within a package are crucial to the RF and millimeter wave performances, this paper will investigate RF and millimeter wave performances of several different transmission line structures in different stacking of low cost coreless substrates of FOCLP. The loss and beta of transmission lines on these substrates will be compared to provide a basis for future substrate stacking selection. Active dies will also be embedded in this package and the transition from output ports in package to ports on die will be investigated.