Stress migration model for Cu interconnect reliability analysis

Stress migration (SM) reliability data have been treated qualitatively to define pass or fail criteria in the past. However, realistic quantitative SM analysis and lifetime estimates for products were not available due to lack of a suitable SM model. In this paper, we establish a comprehensive SM model for quantitative stress-induced-voiding (SIV) risk analysis for 32 nm technology and beyond. It was found that the SIV risk is dependent on both stress temperatures and geometric structural line widths as driving forces. Based on the new SM model, the SM lifetime can be estimated from measurable SM data and accelerated SM test methods can be designed to meet the qualification criteria.