Scaling Effects on Microstructure and Implication on resistivity of Co Nanointerconnects

The continued scaling of Cu low k technology is facing serious challenges imposed by basic limits from materials, processing and reliability, especially the rapid increase in line resistivity. This has generated great interests recently to further develop Cu nanointerconnects and alternatives, particularly Co nanointerconnects beyond the 10nm node. The scaling effect on microstructure for Co interconnects was investigated using high-resolution TEM precession technique for line width from 220nm to 26nm. The dominant <0001> sidewall texture suggested that strain energy is important for texture evolution, a conclusion supported by large abnormal grain growth observed. The TEM study was supplemented by Monte Carlo simulation to project the grain growth for future technology nodes based on total energy minimization. Together the TEM and simulation results were used to project the scaling effect on the resistivity of Co nanolines.