Cu Nanolines for RF Interconnects: Electrical Characterization

In this paper, we investigated the RF properties of Cu nanolines that are arranged in a coplanar waveguide (CPW) configuration. The signal tracks for the CPW transmission lines (CPW TLines) were either single Cu nanolines or multiple parallel Cu nanolines of equal total width and varying number. The total width was kept constant in order to study the validity of the litz-wire concept on the on-chip integrated CPW TLines. The metallization thickness was 100 nm and their width ranged from 50 nm to 1 μm. The RF characteristics of the nanolines were measured in the frequency range 40 MHz-40 GHz and the results were compared with those obtained from electromagnetic simulations. For these frequencies and nanolines dimensions, no improvement was observed when splitting the single line into multiple parallel lines. On the contrary, the resistance was increased according to the corresponding resistivity increase.