Self-Annealing Textures of Copper Damascene Interconnects

Abstract

The properties of deposited metal films and interconnect structures at submicrometer scale are sensitive functions of microstructural features. Therefore, understanding of the factors which control microstructural evolution is necessary for the development and design of reliable, manufacturable interconnect structures, especially in copper damascene interconnects. The annealing textures of copper interconnects depend on their deposition textures and geometries. The copper interconnects are subjected to stresses even at room temperature, which in turn give rise to strain energies. The stress distributions in interconnects are not homogeneous, which in turn give rise to non-fiber type textures after annealing. The self-annealing textures of interconnects is discussed based on the strain-energy release maximization model, in which grains whose Young’s modulus direction is parallel to the absolute, maximum stress direction grow in preference to others.