Multi-chip packaging for high speed superconducting circuits

We report the development of a multi-chip module (MCM) technology using Nb metallization and benzocyclobutene (BCB) polymer dielectric. The Nb/BCB structure displays very low loss, has low processing temperature, and forms a wide range of microstrip transmission line impedances. We are developing flip chip, solder attachment for die mounting. We also report the electrical characterization of Nb/BCB/Nb for both microstrip resonators, delay lines, and bandpass filters.>