Empirical Study on the Applicability of the Embedded Wafer Level BGA Package for Cryogenic RF Applications

This work investigates the suitability of an embedded wafer-level ball grid array (eWLB) package for cryogenic applications e.g., quantum computer, quantum sensing and radio astronomy. A 12GHz power amplifier (PA) manufactured in a BiCMOS technology and encapsulated in an eWLB package is used for the empirical study. This work demonstrates the cryogenic suitability of the eWLB packaging technology by comparing large-signal measurements results of the bare die and packaged version of the PA characterized at around 6K. The presented measurements provide insights in the electrical connectivity characteristics of the package. Moreover, computer tomographic cross-section analysis reveals the robustness of the package against mechanical stress induced by thermal cycling.