Reliability improvement of Cu/low-k interconnects by integrating novel single pass single wafer wet clean

A novel solvent-based single wafer clean process with megasonic feature and single pass fresh solvent spray has been developed This process mitigated the copper undercut problem which existed in the conventional system. The electrical parametric performance meets or outperforms that from the baseline bench process. More importantly, the undercut mitigation resulted in significant improvements on Cu/low-k interconnect reliability including EM and SM. Physical analysis and integration results indicate the feasibility and advantages of integrating this process into the state-of-the-art dual damascene process flow.