Annealing effect on the structure characteristics of nano-scale damascene copper lines

High-resolution electron backscatter diffraction (EBSD) technique was applied for systematic and detailed study of grain structure and texture changes in various microstructural regions of nano-scale damascene copper lines after annealing in a wide temperature range of 200-500°C. To ensure reliability of the obtained results, large EBSD maps including several thousand grains were obtained in each case. Above 200°C, the grain structure was established to be surprisingly stable in both the overburden layer as well as within the lines. The grain growth in the lines was supposed to be suppressed by pinning effect of second-phase particles entrapped during electrodeposition process.