1. Optimally Minimizing Overlay Violation in Self-aligned Double Patterning Decomposition for Row-based Standard Cell Layout in Polynomial Time Z. Xiao, Y. Du, H. Tian, M. D.F. Wong Department of ECE University of Illinois at Urbana-Champaign ICCAD 2013

2. Outline Introduction Preliminaries SADP Decomposition Algorithm for Row-based Standard Cell Layout Experiments Conclusion

3. Introduction Self-aligned double patterning (SADP) is one of the most promising double patterning techniques for sub-20nm nodes.

4. Introduction This paper focus on SADP decomposition problem for row-based standard cell layout. The objective is to minimize the total number of overlay violations.

5. Preliminaries Overlay Violation  The critical sides that are not protected by sidewalls.  Consider the line ends of the feature as non-critical, while the sides are critical.

6. Preliminaries SADP Decomposition in Row-based Standard Cell Layout  The standard cells in a library have the same height but may have different width.  Multiple rows are stacked vertically to complete a row-based standard cell layout. Standard CellA standard cell row

7. Preliminaries Problem Definition  Given a row-based standard cell layout with fixed height.  Our objective is to decompose the layout into a set of core patterns and block patterns for SADP patterning.  The number of overlay violations is minimized.

8. Preliminaries SADP Mask Rules  The minimum width of a core (block) pattern is d  The minimum distance between two adjacent patterns is s  The width of sidewalls is w

9. SADP Decomposition Algorithm Two methods to generate a feature:  Use a core pattern that has an exact same shape as the feature.  An auxiliary core pattern is placed along the feature sides, such that the sidewalls generated define the feature.

10. SADP Decomposition Algorithm Finding decomposition from an assigment  Merge a pair of conflicting features when they are both assigned as cores. Core-core-merge (CCM)

11. SADP Decomposition Algorithm Finding decomposition from an assigment  Feature B is assigned as core and merges with the auxiliary core of A. Core-aux-merge (CAM)

12. SADP Decomposition Algorithm Finding decomposition from an assigment  Removal of the conflicting part of auxiliary core.  Merging conflicting main core and auxiliary core. Core-aux-merge (CAM)Core-aux-removal (CAR)

13. SADP Decomposition Algorithm Finding decomposition from an assigment  Two auxiliary cores can be merged together directly. Aux-aux-merge (AAM)

14. An Example

17. Experiments

18. Conclusion This paper discussed the SADP decomposition for row-based standard cell layout. Experimental results with industrial level standard cells showed that the proposed method can solve large scale problems in a relatively short time.