电迁移诱发表面扩散下沿晶微裂纹的演化

发布时间：2018-12-10 18:05

【摘要】：随着微电子技术的快速发展,铜内连导线的失效问题日益受到关注.基于表面扩散和蒸发—凝结的经典理论及其弱解描述,建立描述电迁移下微结构演化的有限单元法,对铜材料内沿晶微裂纹在电迁移诱发表面扩散下的不稳定外形演化进行了有限元模拟.详细讨论了电场、形态比和晶界能与表面能比值对沿晶微裂纹演化的影响.结果表明:沿晶微裂纹在沿着晶界和电场方向发生漂移的过程中存在分节与不分节两种形貌演化分叉趋势,且裂腔分节存在临界形态比βc和临界电场值χc.当β≥βc或χ≥χc时,沿晶微裂纹会沿着晶界分节成一大一小两个小沿晶微裂纹.沿晶微裂纹分节时间随形态比和电场的增大而减小,即形态比和电场的增大都使沿晶微裂纹加速分节.而临界电场值χc随着形态比的增大而减小;临界形态比βc随电场的增大而减小.也就是说形态比和电场的增大还将有助于沿晶微裂纹分节.此外,沿晶微裂纹分节时间要比晶内微裂纹的小,即晶界的存在有助于加速裂腔分节.
[Abstract]:With the rapid development of microelectronic technology, the failure of copper internal conductor has been paid more and more attention. Based on the classical theory of surface diffusion and evaporation-condensation and its weak solution description, a finite element method for describing the evolution of microstructure under electromigration is established. The unstable shape evolution of intergranular microcracks induced by electromigration was simulated by finite element method. The effects of electric field, morphology ratio and the ratio of grain boundary energy to surface energy on the evolution of intergranular microcracks are discussed in detail. The results show that the intergranular microcracks drift along the grain boundary and the electric field, and there are two morphologies evolution and bifurcation trends, the critical morphology ratio (尾 c) and the critical electric field value (蠂 c). When 尾 鈮，

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