Vertex-based opc for opening patterning

A method comprising:

• receiving a target layout pattern associated with an opening to be produced on a substrate;
• determining a regular polygon having a plurality of vertices inside the target layout pattern, wherein the vertices are inside or on a perimeter of the target layout pattern, and wherein the regular polygon is an initial layout pattern of the opening;
• performing an iterative correction of the initial layout pattern, the iterative correction comprising:
• projecting, onto the substrate, the initial layout pattern as a first iteration of a layout pattern of the opening;
• determining a first error between the target layout pattern of the opening and the projected first iteration of the layout pattern of the opening;
• and
• adjusting the initial layout pattern of the opening by moving the vertices away from an initial location of the vertices to generate a next iteration of the layout pattern of the opening;
• and
• continuing the adjusting, the projecting, and the determining until a criterion is satisfied and a final iteration of the layout pattern of the opening is generated, wherein substantially circularly symmetric illumination is used for the projecting.

A layout pattern enhancement system, comprising:

• a main controller;
• a mask enhancer coupled to the main controller;
• a mask projector coupled to the main controller;
• an analyzer module coupled to the main controller, wherein the analyzer module is configured to receive a target layout pattern to be produced on a substrate, wherein the analyzer module is configured to receive a command from the main controller to parse the target layout pattern to determine a first sub-pattern of the target layout pattern comprising a rectangular shape having one or two substantially line-end shapes at one or both ends of the rectangular shape, and wherein the analyzer module is configured to fit one or two arc shapes inside the rectangular shape to the one or two substantially line-end shapes and replace the one or two substantially line-end shapes of the first sub-pattern of the target layout pattern with the one or two arc shapes;
• the mask enhancer is coupled to the analyzer module through the main controller and is configured to receive the first sub-pattern from the analyzer module and define a portion of a regular polygon having a plurality of vertices on a first arc shape of the one or two arc shapes at a first end of the rectangular shape, wherein the plurality of vertices of the portion of the regular polygon coincide with a boundary of the first arc shape at the first end of the rectangular shape of the first sub-pattern of the target layout pattern, and wherein the portion of the regular polygon is an initial layout pattern of the first end of the rectangular shape of the first sub-pattern, wherein:
• the mask projector is configured to project, onto the substrate, the initial layout pattern as a first iteration of a layout pattern of the first end of the rectangular shape of the first sub-pattern;
• the analyzer module is further configured to determine a first error between the target layout pattern of the first end of the rectangular shape of the first sub-pattern and the projected first iteration of the first end of the rectangular shape of the first sub-pattern;
• and
• the mask enhancer is further configured to adjust the initial layout pattern by moving the vertices away from the boundary of the first arc shape to generate a next iteration of the layout pattern of the first end of the rectangular shape of the first sub-pattern;
• and
• the main controller is further configured to continue the adjusting, the projecting, and the determining until the first error is below an error threshold and a final iteration of the layout pattern of the first end of the rectangular shape of the first sub-pattern is generated.