Fragmentation of Square Pattern Mask with Small Corner-to-Corner Space

Hole layer mask with small corner-to-corner space is usually been limited by mask rule check in OPC. For 28nm and below node, via or contact layer square pattern edges need not fragmentation in general. This paper investigates fragmentations of hole layer square mask with small corner-to-corner space to make contour critical dimension on target. The potential risks of fragmentations and limit conditions of fragments movement are also been discussed. Comparison of square pattern mask with or without fragments ADI results is also been studied in this paper.