Reliability Characterization of a Flexible Interconnect for Cryogenic and Quantum Applications

We present reliability characterization of a polyimide/copper-based flexible interconnect designed for cryogenic and quantum computing applications. This interconnect design uses commercial fabrication processes and off-the-shelf parts. Experiments were performed on production flexible interconnect parts. Samples underwent a series of tests including rapid thermal cycling by liquid helium submersion, cold bias stress, room temperature fatigue bending, connect-disconnect of the interconnect connector and in-plane shear stress. The results found that the samples are remarkably robust. All tested flexible interconnect tapes showed no failures in the entire study post reliability stress. Failures were observed on the connector solution chosen for this engineering design. This paper will present the experimental data and results from the flexible interconnects bonded to a commercial off-the-shelf connector part. A model is described to estimate a system failure rate due to the flexible interconnect and connector subassembly failures. The results of this study conclude that the flexible interconnect tapes are well suited for cryogenic temperature applications.