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提出了一种基于微观晶粒尺寸分布的Cu互连电迁移失效寿命模型.结合透射电子显微镜和统计失效分析技术。研究了Cu互连电迁移失效尺寸缩小和临界长度效应及其物理机制.研究表明,当互连线宽度减小,其平均晶粒尺寸下降并导致互连电迁移寿命降低.小于临界长度的互连线无法提供足够的空位使得铜晶粒耗尽而发生失效.当互连长度大于该临界长度时,在整个电迁移测试时间内,部分体积较小的阴极端铜晶粒出现耗尽情况.随着互连长度的增加该失效比例迅速增大,电迁移失效寿命减小.当互连长度远大于扩散长度时,失效时间主要取决于铜晶粒的尺寸,且失效寿命和比例随晶粒尺寸变化呈现饱和的波动状态.
A model of Cu interconnect electromigration failure lifetime based on microscopic grain size distribution is proposed, which combines transmission electron microscopy and statistical failure analysis techniques. The size reduction and critical length effect and the physical mechanism of electromechanical migration in Cu interconnect have been studied.The results show that the average grain size decreases and the lifetime of the electromigration migration decreases when the width of the interconnect decreases.The smaller the critical length The connections fail to provide enough vacancy to cause depletion of the copper grains. When the interconnect length is greater than the critical length, some of the smaller cathodic copper grains are depleted throughout the electromigration test time. With the increase of interconnect length, the failure rate increases rapidly and the electromigration failure lifetime decreases. When the interconnection length is much longer than the diffusion length, the failure time mainly depends on the size of the copper grains, and the failure lifetimes and proportions vary with the grain size Dimensional changes show a saturated state of volatility.