Interplay and influence of thermomechanical stress in copper-filled TSV interposers

In this paper we use finite element simulations to determine the influence of two key design parameters on the thermomechanical stress and the stress interplay in copper-filled TSV arrays. The two parameters are the via´s pitch-to-diameter ratio and thickness-to-radius (aspect) ratio. Our analytical results has suggested that the in-plane stress interplay becomes insignificant when the TSV pitch is at least five times of the via´s radius. This criterion will be numerically verified in this paper. This work also suggests that it would be inadequate to approximate the thermomechanical stress into a simplified 2D models even for a small H/D ratio (which resembles a think, 2D-like structure).