Effect of Interconnect Linewidth on Evolution ofIntragranular Microcracks Due to Electromigration Analyzedby Finite Element Method

TN925; The effect of interconnect linewidth on the evolution of intragranular microcracks due to surface diffusion induced by electromigration is analyzed by finite element method. The numerical results indicate that there exists critical values of the linewidth (h) c,the electric field χc and the aspect ratio βc. When (h) > (h) c,χ< χc or β< βc,the microcrack will evolve into a stable shape as it migrates along the interconnect line. When (h) ≤ (h) c,χ≥ χc orβ≥ βc, the microcrack will split into two smaller microcracks. The critical electric field,the critical aspect ratio and the splitting time have a stronger dependence on the linewidth when (h) ≤ 6. In addition,the decrease of the linewidth, the increase of the electric field or the aspect ratio is beneficial to accelerate microcrack splitting,which may delay the open failure of the interconnect line.