Eda tool and method, and integrated circuit formed by the method

A system comprising:

• a non-transitory, computer readable storage medium for storing data representing a layout of a layer of an integrated circuit (IC) comprising a plurality of polygons defining circuit patterns to be divided among a number (N) of masks for multi-patterning a single layer of a semiconductor substrate, where N is greater than one;
• an EDA tool configured for:
• adding one or more stitches to at least a subset of the polygons, to divide each polygon within that subset into at least N parts, such that parallel parts of adjacent polygons are assigned to different masks from each other;
• determining a respective total area of polygons and parts of polygons assigned to each respective mask;
• inserting at least one additional stitch in at least one of the polygons or parts of polygons to reduce a difference between the respective total areas of polygons and parts of polygons assigned to each mask;
• and
• storing data representing assignment of each of the parts in each set to respective masks in a non-transitory, computer readable storage medium that is accessible for use in a process to fabricate the N masks.

A non-transitory machine readable storage medium encoded with computer program code, such that when the computer program code is executed by a processor, the processor performs a method comprising:

• accessing data representing a layout of a layer of an integrated circuit (IC) comprising a plurality of polygons defining circuit patterns to be divided among a number (N) of masks for multi-patterning a single layer of the IC, where N is greater than one;
• for at least two parallel polygons in the layout, inserting at least one stitch in each polygon to divide each of the at least two polygon into at least N parts, such that parallel adjacent parts of different polygons are assigned to different masks from each other, the parts of each stitched polygon are assigned to respective masks according to a sequence, and each polygon has a different sequence offset from an adjacent one of the at least two polygons;
• and
• storing data representing assignment of each of the parts in each set to respective masks in a non-transitory, computer readable storage medium that is accessible for use in a process to fabricate the N masks.