Method for integrated circuit mask patterning

A method of converting an IC mask pattern that is not a rectangular shape into at least one rectangle for mask fabrication, comprising:

• using a computer, determining a rectangle approximating the IC mask pattern, wherein the rectangle and the IC mask pattern share a center of mass;
• calculating a pattern approximation error between the rectangle and the IC mask pattern;
• when the pattern approximation error is less than a user-defined threshold, accepting the rectangle as a replacement of the IC mask pattern in subsequent mask fabrication,
• otherwise,
• splitting the IC mask pattern into two subparts;
• and
• recursively converting each of the two subparts that is not already a rectangular shape into at least one rectangle.

A method comprising the steps of:

• receiving an integrated circuit (IC) design layout, the IC design layout having a first pattern that is not in a rectangular shape;
• using a computer, determining a rectangle approximating the first pattern;
• calculating a deviation between the first pattern and the rectangle;
• and
• upon a condition in which the deviation is less than a user-defined threshold, replacing the first pattern with the rectangle in the IC design layout,
• otherwise, performing the steps of:
• splitting the first pattern into a plurality of subparts;
• and
• for each of the plurality of subparts, recursively performing the steps of determining, calculating, conditionally replacing, and conditionally splitting.