The influence of strain energy on abnormal grain growth in copper thin films

Biaxial stress and strain in (100) and (111) oriented grains have been measured as a function of annealing temperature for a Cu film on an oxidized Si substrate which exhibits abnormal (100) grain growth. The observed behavior indicates isostrain averaging, which is consistent with grain growth that is controlled by strain energy density minimization. In contrast, two films which do not exhibit (100) abnormal grain growth appear to follow isostress averaging. Strain energy density minimization in this situation favors (111) grain growth.