The fabrication of Copper coplanar waveguides on Silicon substrates was investigated. Plated copper metallization was found to improve the performance of coplanar waveguide transmission lines, fabricated on CMOS-compatible silicon substrate. Copper/polyimide devices increased the phase velocity of the transmission line by a factor of √2. The lower resistance of the copper and improved substrate isolation obtained with the low-k polyimide dielectric was found to enhance the performance of these lines.
Journal of Vacuum Science and Technology A
Department of Electronics

Amaya, R, Levenets, V., Tarr, N.G, & Plett, C. (2004). Copper coplanar waveguides in Si substrates for 10 GHz applications. In Journal of Vacuum Science and Technology A (Vol. 22, pp. 847–850). doi:10.1116/1.1647587