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 12 GHz 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 6 K. 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.