Macroscopic and microscopic interface adhesion strength of copper damascene interconnects

Macroscopic and microscopic adhesion strength of damascene interconnects was investigated by evaluating local strength through delaminating different scales of adhesion area under SEM observation. Macroscopic strength obtained by the areas larger than the copper grain was almost constant after considering the macroscopic plastic deformation. However, microscopic strength obtained by the areas smaller than the copper grain spread around the macroscopic strength and was highly sensitive to the copper grain structure, especially the grain boundary.