High quality broadband passive components are needed for MMIC/MIC in silicon. Coplanar waveguides (CPW) provide an effective way to implement passives in microwave ICs. Silver "fat" wires in the back end interconnects, used for CPW fabrication, will reduce the bulk resistive loss in metallization to the lowest possible level, which is vital to minimize noise. Electromigration, electrochemical migration, and agglomeration issues are not a problem for silver microwave passive components, because of their coarse dimensions and the low current densities encountered in these structures. In this work Ag and Cu CPWs were designed, fabricated, and tested. Silver CPWs showed a 2-3 Ω/cm improvement in resistance over copper devices at 20 GHz.

doi.org/10.1116/1.2013311
Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Department of Electronics

Levenets, V.V. (Vladislav V.), Amaya, R, Tarr, N.G, Smy, T, & Rogers, J. (2005). Silver coplanar waveguides as the passive components of choice for microwave integrated circuits. Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, 23(5), 1924–1928. doi:10.1116/1.2013311