“…3, conflicts exist in this layout with three patterns, 1, 2, and 3. Without using stitches, a popular layout decomposition method, such as the natural split decomposition mentioned in [29], would assign a part of patterns to OPT mask # 1 and the other part of patterns to OPT mask #2, but would result in a conflict between patterns. By inserting a stitch in pattern 1 that assigns respective sub patterns to OPT masks #1 and #2, a better decomposition could be achieved without any conflicts.…”