Functional Printing of MMIC-Interconnects on LTCC Packages for sub-THz applications

In this paper, the authors presents about anAerosol Jet printed interconnect technology between a GaAs MMIC and an LTCC packaging. Conductive silver nanoparticle and a dielectric polymer-based glob-top are utilized to fabricate die attach, dielectric ramp, and GCPW (Grounded Coplanar Waveguide) transmission line interconnect structures in order to interface a GaAs MMIC with an LTCC (Low Temperature Cofired Ceramic) packaging substrate. The GCPW lines were printed using the Optomec Aerosol Jet 300 printer with silver nanoparticle ink from Paru. The printed minimal resolution of the interconnection was 34 mm with a gap of 23 mm. Simulation and measurement results of printed interconnects were evaluated in a frequency range between 1 and 225 GHz. The printed interconnects including the MMICs and GCPWs on LTCC have shown an insertion loss of ca. 2 dB at 140 GHz. The reflection coefficient stayed below -10 dB until 210 GHz.