LP based white space redistribution for thermal via planning and performance optimization in 3D ICs

Thermal issue is a critical challenge in 3D IC circuit design. Incorporating thermal vias into 3D IC is a promising way to mitigate thermal issues by lowering down the thermal resistances between device layers. However, it is usually difficult to get enough space at target regions to insert thermal vias. In this paper, we propose a novel analytical algorithm to re-allocate white space for 3D ICs to facilitate via insertion. Experimental results show that after reallocating whitespaces, thermal vias and total wirelength could be reduced by 14% and by 2%, respectively. It also shows that whitespace distribution with via planning alone will degrade performance by 9% while performance-aware via planning method can reduce thermal via number by 60% and the performance is kept nearly unchanged.