The Evolution Of Intragranular Microcraks Induced By Multi-Physical Fields

With the ever-increasing microminiaturization of integrated circuit, metal film interconnect reliability under multi-physical fields has become a more and more important scientific problem. The migration and evolution of microcracks in metal material induced by stress field and electric field is the major failure mode of interconnect. This paper is focused on the evolution of intragranular microcrack in metal material due to strain and electromigration induced surface diffusion.First of all, a simplified evolution model of intragranular microcracks under electric field and stress field is established. Based on the theory of surface diffusion and its weak statement, a finite element scheme is implemented and a program is developed for simulating the evolution of two-dimensional microcracks within grains under stress field and electric field. And the reliability of the program is proved in detail.Then, the evolution of intragranular microcracks induced by the stress field, the electric field and the curvature of surface is simulated, which are in a long thin elastic conductor. The effects of the aspect ratio, the magnitude and the state of the stress, the electric field and the conductor boundary on the evolution are investigated detailedly in the dissertation.Finally, a simplified model of intragranular microcracks with inter pressure under electric field is established and a new module is added to the computer program. The effects of the internal pressure on the electromigration are analyzed detailedly by the finite element method.