Evolution of grain and micro-void structure in electroplated copper interconnection lines

摘要

A detailed investigation has been carried out into the evolution of grain size and grain orientation in electroplated Cu interconnection lines during annealing. Although annealing causes the average grain size to increase, very small grains are found to persist in the distribution, even when the average grain size is large. These small grains have been investigated in detail to determine the reason for their thermal stability. In addition, the presence of small micro-voids has been studied for wafers with different grain sizes. The evolution and redistribution of these micro-voids is correlated to the grain growth mechanism.