Removal of oxides from copper surface using femtosecond and nanosecond pulsed lasers

We analyzed the process of using femtosecond and nanosecond pulsed lasers for removing the oxide layer from bulk copper and optimized the process parameters. A femtosecond laser (Ti:Sapphire) and two nanosecond lasers (Nd:YAG, excimer) were used to remove oxide layers composed of cupric oxide (CuO) and cuprous oxide (Cu2O) from copper. Femtosecond laser ablation reduced the thickness of native oxide layers to <20 nm with no significant thermal side effects. Nanosecond laser ablation removed a substantial portion of the oxides but thermal side effects such as surface melting and resolidification generated re-oxidation layers on the order of 100-nm thick.