The method of computer aided vacancy migration analysis was developed to predict the stress-induced voiding reliability. In this method, the distribution of hydrostatic stress was calculated by finite element analysis, and the vacancy concentration distribution was calculated by finite difference analysis. Here, stress-induced voiding acceleration tests were conducted on various widths of Cu lines in organic ultralow-k dielectric (Cu/Ta/ULK/SiCN) or silicon oxide dielectric (Cu/Ta/SiO2/SiCN) and these results were compared with the results of the vacancy migration analyses. The number of SiV failures increased in line with a width of 0.35µm for Cu/Ta/SiO2/SiCN interconnects and 0.20µm for Cu/Ta/ULK/SiCN interconnects, respectively, under stress-induced voiding acceleration tests. The results obtained by vacancy migration analysis showed similar behavior to the results of stress-induced voiding acceleration tests. These results revealed that the vacancy migration analysis was useful for predicting the reliability of interconnects.

Prediction of Stress Induced Voiding Reliability in Cu Damascene Interconnect by Computer Aided Vacancy Migration Analysis. H.Shigeyama, T.Nemoto, A.T.Yokobori: Japanese Journal of Applied Physics, 2011, 50, 05EA05