REMOVAL OF SURFACE OXIDES ON COPPER BY PULSED-LASER IRRADIATION

The removal of an oxide layer from a copper surface by pulsed laser ir radiation was studied to improve the soldering property of Sn-Pb. The copper surface was irradiated by ArF excimer laser or the second harmo nic pulsed Nd3+:YAG (532 nm) laser. It was found that the thin surface oxide layer can be removed by laser irradiation even in air without d egradation of the copper surface layer. However, highly intense irradi ation causes significant changes in the surface morphology, resulting in the reduced wettability for the Sn-Pb solder.