Backend CAD flows for "restrictive design rules"

To meet challenges of deep-subwavelength technologies (particularly 130 nm and following), lithography has come to rely increasingly on data processes such as shape fill, optical proximity correction, and RETs like altPSM. For emerging technologies (65 nm and following) the computation cost and complexity of these techniques are themselves becoming bottlenecks in the design-silicon flow. This has motivated the recent calls for restrictive design rules such as fixed width/pitch/orientation of gate-forming polysilicon features. We have been exploring how design might take advantage of these restrictions, and present some preliminary ideas for how we might reduce the computational cost throughout the back end of the design flow through the post-tapeout data processes while improving quality of results: the reliability of OPC/RET algorithms and the accuracy of models of manufactured products. We also believe that the underlying technology, including simulation and analysis, may be applicable to a variety of approaches to design for manufacturability (DFM).