A Layout Sensitivity Model for Estimating Electromigration-vulnerable Narrow Interconnects

During back-end manufacturing process of IC, intervention of spot defects induces extra and missing material of interconnects causing circuit failures. Interconnect narrowing occurs when spot defects induce interconnects missing material without resulting in a complete cut. The narrow sites of defective interconnects favor electromigration that makes narrow interconnects more likely to induce a chip failure than regular interconnects. In this paper, an innovative layout sensitivity model accounting for “narrow” defects is derived. The paper also pioneers estimation of the probability of narrow interconnects in the die. The layout sensitivity model for narrow interconnects is tested and compared to actual and simulated data. Our layout sensitivity model predicts the probability of narrowing with 3.1% error, on average. The model is then combined with electromigration constraints to predict mean-time-to-failure of chips manufactured in future technologies down to 32 nm node. The paper concludes with some other possible applications of the narrow interconnect predictive model.