Effect of Trench Aspect Ratio on Microstructure and Texture in Damascene Cu Interconnects

Abstract

The effect of trench aspect ratio and line spacing on microstructure and texture in annealed damascene Cu interconnects has been investigated. The X-ray diffraction (XRD) and electron backscatter diffraction (EBSD) analyses of Cu lines, showed a preferred {111} orientation and the trenches reduce the proportion of high-angle grain boundaries and increase the fraction of coincidence site lattice (CSL) grain boundaries, comparing with the Cu blanket film. In addition, both trench aspect ratio and line spacing can largely affect the microstructure and texture in annealed damascene Cu interconnects.