銅配線における応力誘起ボイドの成長メカニズムと抑制手法の研究

概要

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We studied stress-induced voiding under via-holes in copper interconnects. The internal stress developed in copper interconnects was analyzed by using a finite-element method. The intrinsic stress of the construction materials was measured to analyze the internal stress. We investigated the relationship between the analyzed copper-line stress under the via-hole and the increase in electrical resistance of copper-interconnect-structure test samples. By comparing the results, it was found that the resistance due to the growth of stress-induced voids increases with the increase in the copper-line stress and in the stress gradient. Furthermore, molecular dynamics simulations showed that both the stress and stress gradient activate copper-atom diffusion, which is a dominant factor in void growth. Therefore, the reduction of the copper-line stress and stress gradient is important in suppressing the growth of stress-induced voids.