Cryogenic packaging for multi-GHz electronics

To meet the packaging needs of current superconducting electronics, we have developed high speed multi-chip modules (MCMs), flexible ribbon cabling, and press-contact surface mounts. We describe these new technologies and include techniques for high-reliability, high-yield assembly. In addition, we present electrical and thermal characterizations of a system which incorporates these new technologies. Electrical characterization includes multi-GHz insertion loss and digital-data transmission measurements. We have performed extensive thermal modeling using SINDA software and have experimentally verified these simulations. We present the results and their general applicability to these new cryogenic packaging technologies.