Stress-induced-voiding risk factor and stress migration model for Cu interconnect reliability

SM reliability data have been treated qualitatively to define pass or fail criteria in the past. However, realistic quantitative stress-induced-voiding (SIV) risk analysis and lifetime estimates for products were not available due to lack of quantitative data and a suitable SM model. In this paper, we provide quantitative analysis of SIV risk based on geometry factors and further establish a comprehensive SM model for SM lifetime estimation for 32nm technology and beyond. An SIV risk factor is defined to quantify the relative risks of Cu BEOL interconnect structures. Based on the new SM model, an effective geometry factor was found for an accelerated SM test method to perform SM lifetime estimation from measurable SM data.