Self-Aligned Double Patterning (SADP) Layout Decomposition

Minoo Mirsaeedi1,  J. Andres Torres2,  Mohab Anis3
1University of Waterloo, 2Mentor Graphics Corp., 3The American University of Cairo


Double patterning lithography (DPL) is the most likely manufacturing process for sub-32nm technology nodes; however, there are several double patterning strategies each of which exhibits different layout decomposition challenges. Self-aligned double patterning (SADP) has attracted much interest due to its robustness against overlay errors, but SADP compliance depends strongly on the characteristics of the individual masks generated during the layout decomposition. This work establishes SADP decomposition requirements and proposes a litho-friendly layout decomposition method. First, we explain the main parameters that limit printability of SADP decomposed layouts. In-silico experiments indicate that layout patterns which are printed by the Trim mask may experience the highest levels of image transfer sensitivity. For that reason, these patterns should be assisted by sidewalls of spacer patterns which are robustly printed. Next, we present an ILP-based decomposition method which avoids decomposition conflicts and sensitive Trim edges simultaneously. Our experiments on several industrial designs reveal that the proposed method decreases the total length of sensitive Trim patterns and consequently reduces the overall edge placement error significantly.