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).