Compared with on-chip routers, the existing commercial tools for off-chip routing have a much lower routability and often result in a large number of unrouted nets for manual routing. In this paper, we develop an effective, yet efficient, substrate routing algorithm, applying dynamic pushing to alleviate the net ordering problem and reordering and rerouting for further wire length and congestion reduction. Compared with an industrial design tool that leaves 936 nets unrouted for nine industrial designs with a total of 6100 nets, our algorithm reduces the unrouted nets to 212, a 4.5-times net number reduction and practically more design time reduction.

Three-dimensional integrated circuits (3D ICs)

No abstract

Structured ASICs present an attractive alternative to reducing design costs and turnaround times in nanometer designs. As with conventional ASICs, such designs require global wires to be buffered. However, via-programmable designs must prefabricate and preplace buffers in the layout. This paper proposes a novel and accurate statistical estimation technique for distributing prefabricated buffers through a layout. It employs Rent's rule to estimate the buffer distribution required for the layout, so that an appropriate structured ASIC may be selected for the design. Experimental results show that the buffer distribution estimation is accurate and economic, and that a uniform buffer distribution can maintain a high degree of regularity in design and shows a good timing performance, comparable with nonuniform buffer distribution.