Fabrication and characterization of a high temperature superconducting multichip module

A process for fabricating high temperature superconducting (HTS) multichip module - deposited (MCM-D) substrates has been developed and tested. The module consists of two digital gallium arsenide bare die connected by YBa2Cu3O7-delta (YBCO) HTS interconnects to form two ring oscillators on a 2.25 cm(2) MCM-D substrate. The interconnections consist of two wiring layers of YBCO separated by a 4-5 mu m silicon dioxide interlevel dielectric. The 50 mu m wide signal lines are routed between 150 mu m power and ground lines with 75 mu m spacings to form an interconnected mesh power system (IMPS). Connection between the two YBCO layers is accomplished with low contact resistance 40 mu m gold vias through the interlevel dielectric layer. Ultrasonic Al wire bonds serve as electrical connections to gold/YBCO bond pads on the MCM substrate.