The Microcrak Evolution Due To Surface Diffusion And Grain-boundary Diffusion Induced By Multi-physical Fields

With the rapid development of microelectronics technology, the integrated circuits are increasinglyminiaturized. The reliability of metal film interconnect under multi-physical fields has drawn evenmore attentions. The migration and evolution of microcracks in metal material induced by stressfield/electric field and thermal gradient is the major failure mode of interconnect. This paper isfocused on the evolution of intragranular and transgranular microcracks in metal material due tocurvature, strain, electromigration and thermal gradient.First, a simplified evolution model of intergranular microcrack under curvature, electric field, stressfield and thermal field is established. A finite element scheme is implemented and a program isdeveloped for simulating the evolution of two-dimensional intragranular and intergranularmicrocracks under stress field, electric field and thermal field. The reliability and accuracy of theprogram is verified in details.Then, the evolution of intergranular microcrack induced by stress field, electric field, thermal fieldand the curvature of surface is simulated. The effect of initial aspect ratio, two diffusion coefficientratio, the magnitude and the state of the stress, electric field and thermal field on the microcrackevolution are investigated detailedly in the dissertation.Finally, a simplified model of intragranular microcracks with inter pressure under multi-physicalfields is established. The effects of the internal pressure on the microcrack evolution are analyzeddetailedly by the finite element method.