Influences of grain structure on thermally induced stresses in 3D IC inter-wafer vias

摘要

We discuss the development of a grain-continuum model to examine the effects of thermally induced stress in 3D IC inter-wafer vias. We demonstrate the approach using stress-driven grain boundary migration in polycrystalline copper films, assuming that migration is due to vacancy migration. The anisotropic elastic constants of single crystal Cu are used for each grain, after aligning them with each grain's orientation. Stresses are thermally induced in a series of films, including one with a dominant < 111 > texture surrounding a single < 100 > grain. Grain boundary velocities are calculated from the fluxes of vacancies to grain boundaries. The computed velocities are then used to update the level sets that represent the grain boundaries using the PLENTE software.