Direct etched Cu characterization for advanced interconnects

Cu wires patterning by direct etch methods is investigated at 300mm wafer level. Cross-sectional sidewall profiles with tapering angles around 74.5° are obtained with a mid-line width of 44 nm, which paves the way to further scaling of this technique. Lower resistivity is demonstrated with respect to conventional Cu damascene process, with low leakage current between adjacent Cu lines. An in-situ 10nm SiN cap is deposited as a passivation to enable electrical and reliability tests. The electromigration (EM) characterization shows promising reliability performance of the direct etched Cu wires.