A Package on Package Assembly Method of SiP Microwave Module based on Heteroid BGA Devices

System in package (SiP) technology provides new development for microwave modules of improving package density and integration level. In this paper, the process flow of package-on-package (PoP) assembly of SiP microwave module based on heteroid ball grid array is designed. The parameters of interconnected alloy balls, stencil and temperature are proposed. The stacking quality, accuracy and strength of interconnections are inspected. The method can be applied in manufacturing PoP microwave modules below 18GHz.