Finite size effects in stress analysis of interconnect structures

A comparison between thermal and residual stress versus temperature data from simple copper thin-film structures on silicon was discussed. It was found that the residual stress at room temperature (RSRT) within 14μm features are equivalent to the blanket film stresses over the entire range. The models that do not specify interface parameters were not able to predict the thermo-mechanical response of simple structures. The results indicated that interconnection models which assume fully elastic behavior and perfectly bonded interfaces may yield inaccurate predictions of the thermo-mechanical response for feature sizes smaller than 10 μm.