Abstract
Crystal orientation of Cu has a significant impact on the local interface adhesion strength between Cu/SiN layers in micro wirings in LSI. Using a finite element model with crystal plasticity, crystal orientation dependence of the interfacial strength was evaluated. For the finite element model, three different Cu crystal orientations such as (100), (110), and (111) facing to the interface were surveyed and also the effect of angle θ=between load and slip directions was evaluated for the cases of 0° and 90°. For the same crystal orientation, the energy release rate G obtained with θ= 90° was higher than 0° because of the higher resistance against slip. For (100), G were 2.02 J/m^2 and 2.02 J/m^2. For (110), G were 1.8 J/m^2 and 2.1 J/m^2. However, G values were 0.06 J/m^2 and 0.22 J/m^2 for (111), which were far smaller than the other cases. Consequently, it was considered that the G value depends mainly on how easily Cu crystal slips beneath the interface. It was demonstrated that the evaluated interface adhesion strength is dependent ofthe crystal orientation for the micro-scale Cu metallization systems in LSI.
