Insights into abnormal grain growth in copper thin films for reduced electrical resistivity: A quantitative multi-order-parameter phase-field study under finite element framework

Abstract

Copper thin films are frequently utilized as microelectronic interconnects. Inducing abnormal grain growth (AGG) may result in reduced electrical resistivity of copper thin films. However, an in-depth understanding of AGG mechanism and quantitative simulation of microstructure evolution during AGG in copper thin films are still missing, prohibiting the regulation and even design of AGG process. In this paper, a multi-order-parameter phase-field (MOP-PF) model coupled with elastic mechanics under a finite element framework was first developed and applied to study the AGG mechanism in copper thin films. It was found that both elastic and grain boundary anisotropies can induce AGG, but elastic anisotropy dominates the evolution of individual grains. Subsequently, a quantitative simulation of microstructure evolution/kinetics during AGG in copper thin films was achieved by inputting the accurate materials parameters from theoretical/experimental data. A further combination with the Mayadas-Shatzkes model led to a quantitative prediction of the evolution of electrical resistivities, from which several feasible strategies were proposed for preparing high-performance copper thin films with reduced electrical resistivities. Furthermore, it is anticipated that the presently developed framework should be generally applicable for quantitative phase-field simulation of grain growth in bulk materials/films.