Numerical simulation of electro-migration failure of copper-filled via holes in ULSI interconnects

By using three-dimension finite element modeling simulation of the current density, the temperature and its gradient distribution in a copper-filled via hole structure was carried out. Then we compared the distributions in the via holes with different barrier materials. Also, via holes with the same barrier material but different obliquity were simulated. The result shows that through optimization of the via hole obliquity, and selection of the barrier material, the reliability of ULSI can be improved.