Crosstalk-aware TSV-buffer Insertion in 3D IC

3D integration is one of the promising technologies to alleviate interconnection delay. Implementing 3D IC is to integrate 2D ICs with Through-Silicon Vias (TSVs). For yield consideration, TSVs are bundled together as a TSV block [1]. Regrettably, this placement will result in crosstalk coupling noises in TSV block, which may cause significant timing degradation. Traditionally, buffer sizing is one of the effective methods to solve the problem. However, we have observed that increasing the TSV-buffer size of aggressor TSV will cause serious timing degradation to the victim TSV in 3D than wires in 2D cases. In this paper, we develop a delay model of a victim TSV surrounded by aggressor TSVs with different driving TSVbuffer sizes. Based on the TSV delay model, we propose (1) an ILP (Integer Linear Programming) method, which is able to find the nearoptimal solution, and (2) an efficient crosstalk-aware heuristic method for practical use. Our experimental results show that the proposed heuristic method only uses 2.56% (3.05%) more TSV-buffers compared to the optimal ILP solution and achieves on average 32.88% (42.40%) and 18.21% (23.06%) area reduction of area-overheads compared to the conventional greedy [2] and separator sets [3] methods in our 2-tier (4-tier) benchmark circuits.