Efficient Analog/RF Layout Closure with Compaction Based Legalization

Advancements in process technology have resulted in tremendous increase in the number of design rules. This has greatly complicated the task of building design rule clean layouts. While EDA tools aid in layout creation for standard cell based ASICs, the problem remains unsolved for custom, analog and RF circuits. For such circuits, layout designers spend lot of time converting functionally correct schematic circuits into acceptable design rule clean layouts. While techniques have been proposed to remove Design Rule Violations (DRVs) with minimum perturbation to hand crafted layouts, designers still spend lot of time to get to layout closure. In the proposed methodology, designers can quickly draw sparse and possibly design rule unclean layouts and then use a compaction based layout legalization to clean up the DRVs and reduce area. This increases the productivity of layout designers and reduces the turnaround time for layout closure. The proposed technique achieves close to best possible area for a given sparse layout, keeps hard macros unaltered, respects relative positions, and removes all violations of modeled design rules. Reported experimental results suggest that this method can be used to automate layout creation process.