A Novel TSV Topology for Many-Tier 3D Power-Delivery Networks

3D integration has the potential to increase performance and decrease energy consumption. However, there are many unsolved issues in the design of these systems. In this work we study the design of many-tier (more than 4 tiers stacked) 3D power-supply networks and demonstrate a technique specific to 3D systems that improves IR-drop over a straightforward extension of traditional design techniques. Previous work in 3D power delivery network design has simply extended 2D techniques by treating through-silicon vias (TSVs) as extensions of the C4 bumps. By exploiting the smaller size and much higher interconnect density possible with TSVs we demonstrate significant reduction of nearly 50% in the IR-drop of our 3D design. Simulations also show that a 3-tier stack with the distributed TSV topology actually lowers IR-drop by 20% over a non-3D system with less power dissipation. Finally, we analyze the power distribution network of an envisioned 1000-core processor with 30 stacked dies and show scaling trends related to both increased stacking and power distribution TSVs. Our 3D analysis technique is validated using commercial-grade sign-off IR-drop software from a major EDA vendor.