Effect of annealing on resistivity of Cu and CuAl metallization

The rapid advancement of highly integrated electronics with enhanced performance has intensified the demand for compatible metallization materials. This study investigates the electrical resistivity and thermal stability of Cu and CuAl thin films for metallization applications. The resistivity of Cu thin films decreases with increasing sputtering power and decreasing working pressure. Both Cu and Al films show improved crystallinity and reduced resistivity with increasing thickness. Thermal annealing further enhances the crystallinity and lowers the resistivity of Cu films. However, Cu films exhibit a significant increase in resistivity when the thickness is reduced to less than 10 nm. CuAl thin films co-sputtered at room temperature have higher resistivities than Cu films, but their resistivities decrease gradually with increasing annealing temperature. Notably, for thicknesses below 10 nm, annealed CuAl films demonstrate lower resistivities than annealed Cu films. These findings highlight the potential of CuAl thin films in high-temperature metallization processes for devices with reduced dimensions, providing valuable insights for the development of next-generation interconnect materials in advanced microelectronics.