Double patterning lithography (DPL) is considered as a most likely solution for 32nm/22nm technology. In DPL, the layout patterns are decomposed into two masks (colors). Two features (polygons) have to be assigned opposite colors if their spacing is less than certain minimum coloring distance. However, a proper coloring is not always feasible because two neighboring patterns within the minimum distance may be in the same mask due to complex pattern configurations. In that case, a feature may be split into two parts to resolve the conflict but the resulting stitch causes yield loss due to overlay error and increases manufacturing cost. While previous layout decomposition approaches perform coloring and splitting separately, in this paper, we propose an algorithm to minimize the number of conflicts and stitches simultaneously. Our algorithm is based on grid layout model and integer linear programming. Two techniques, independent component computation and layout partition, are proposed to reduce runtime of the algorithm. The experimental results show that, compared with the two phase decomposition flow, the proposed algorithm reduces the conflicts significantly using less stitches under reasonable runtime.
['Kun Yuan', 'Jae-Seok Yang', 'David Z. Pan']
Double patterning layout decomposition for simultaneous conflict and stitch minimization