DC-to-Ka-band Broadband Chip-to-Chip Interconnect Using Aerosol Jet Printing

In this paper, we demonstrate a DC-to-Ka-band broadband die-to-die interconnection using aerosol jet printing and compare it to traditional wire-bonding technology. The chips that are connected are commercial-of-the-shelf (COTS) 0-dB attenuators in GaAs substrate with ground-signal-ground (GSG) pads in gold. The chips were connected using the chip-first approach and coplanar waveguide lines with 125 μm signal linewidth and 125 μm gap between signal and ground lines, and no bottom ground connection. The approach is substrate-agnostic and facilitates interconnections with smaller die spacing on any host substrate without using cavities or dielectric ramps. Based on measurements, the CPW interconnect line operates from DC-30 GHz with a maximum insertion loss of 0.27 dB per interconnect, including the losses due to impedance mismatch. To the author's knowledge, this is the first ever demonstration of chip-to-chip interconnect using aerosol jet printing in the ranges of DC-30 GHz.