Fused-Silica Stitch-Chips with Compressible Microinterconnects for Embedded RF/mm-Wave Chiplets

Wireless communication is driving packaging technology innovation towards ultra low-loss and dense multi-chiplet integration. A fused-silica stitch-chip technology is proposed for seamless integration of embedded commercial off-the-shelf (COTS) RF/mm-wave chiplets. The design, fabrication, assembly, and characterization are reported for the first time. Better than 10 dB return loss (RL) and less than 1 dB insertion loss (IL) are measured across 50 GHz bandwidth for 500 μm long stitch-chip channels, which demonstrate superior performance compared to wire-bonds (8.2 dB RL improvement and 4.2 dB IL improvement). The technology also demonstrates high tolerance to substrate coupling with an RL of >10 dB.