Bonding of Multiple Fine Pitch Flexible Cables to a Single Multi-Chip Module for Cryogenic/Superconductive Computing Applications

Thermocompression bonding of a superconductive flexible cable and a non-superconductive flexible cable was performed to a single multi-chip module (MCM) test vehicle using a unique bonding approach. Custom tooling was designed and machined to retrofit an existing flip chip bonder to perform the atypical assembly demonstration. 59 of 61 connections were achieved of the non-superconductive Cu cable. Of the measurable connections down to 5.5 K, 11 of 11 connections were maintained. The superconductive Nb cable demonstrated full connectivity at room temperature. Of the measured connections down to 5 K, an average onset superconducting transition temperature of 8.80 K was observed. Techniques demonstrated provide options beyond conventional bonding approaches for cryogenic interconnects.