Q enhancement with cross-connected coplanar waveguides in thick dual damascene Cu

A 2 times 2 μm, dual damascene, dual metal Cu in SiLK™ process on 200 mm high-resistivity silicon wafers is presented. The lines and spaces in both metal layers can be patterned to submicron dimensions. The extremely low specific contact resistance of the vias, typical for dual damascene Cu, is utilized to make coplanar waveguides, patterned specifically to suppress skin and proximity effects. RF measurements from 1 to 100 GHz show an increase in Q factor up to 30% in the 1 to 15 GHz frequency interval for the patterned lines.