Scaling properties and electromigration resistance of sputtered Ag metallization lines

Resistivity and electromigration were investigated for thin sputtered Ag films and microstructured Ag lines. Resistivities of thin films were found to be lower compared to copper and follow the prediction of the size effect. Microstructured Ag lines show a high electromigration resistance at accelerated stress measurements. Considering joule heating of the lines, the activation energy for electromigration was found to be 0.58 eV. The extrapolated median lifetime of Ag lines was found to be similar or higher than for Cu lines.