Ion implanted double level metal process

The new method to suppress the hillock formation and to improve the electromigration resistance is presented here. By implanting ion to an Al-Si film, density and size of the hillock are reduced and the electromigration resistance is drastically improved. The dose dependency, energy dependency, ion species dependency and the structural analysis data have been studied. The ion-implanted Al-Si film has an amorphous or microcrystalline surface region, and this surface region is considered to prevent the hillock formation and to improve the electromigration resistance. The sheet resistance of the ion implanted Al-Si film is found to be same as that of unimplanted Al-Si film. This new technolgy is widely applicable to the multilevel metal interconnection.