A predictive distributed congestion metric and its application to technology mapping
Proceedings of the 2004 international symposium on Physical design
An efficient technology mapping algorithm targeting routing congestion under delay constraints
Proceedings of the 2005 international symposium on Physical design
Delay-optimal simultaneous technology mapping and placement with applications to timing optimization
Proceedings of the 2008 IEEE/ACM International Conference on Computer-Aided Design
Technology mapping with crosstalk noise avoidance
Proceedings of the 2010 Asia and South Pacific Design Automation Conference
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In this era of deep submicrometer technologies, interconnects are becoming increasingly important as their effects strongly impact the integrated circuit (IC) functionality and performance. Moreover, logic block size is no longer determined exclusively by total cell area and is often limited by wiring area. However, synthesis optimization objectives are focused on minimizing the number and size of library cells. Methodologies that incorporate congestion within the logic synthesis objective function have been proposed in the past. Nevertheless, we will demonstrate that predicting the true congestion prior to layout is not possible, and the effectiveness of any congestion minimization approach can only be evaluated after routing is completed within the fixed die size. In this paper, we propose a practical, complete methodology which first performs congestion-aware technology mapping using a global weighting factor for the technology-dependent synthesis cost function and then applies incremental localized unmapping and remapping on layout congested areas. This complete approach addresses the problem that one global factor is not suited for all layout regions of the design, which might have very different routing demands. Most importantly, through the application of this methodology to industrial examples, we will show that any attempt at a purely top-down single-pass congestion-aware technology mapping is merely wishful thinking.