A method of enhancing a layout pattern includes determining a target layout pattern comprising a disk shape pattern associated with an opening. The method includes defining a polygon having a plurality of vertices on the disk shape pattern. The plurality of vertices coincide with a boundary of the disk shape pattern and the polygon is an initial layout pattern of the opening. The method includes performing an iterative correction of the initial layout pattern. The iterative correction includes projecting the layout pattern of the opening onto a substrate, determining an error between the target layout pattern and the projected layout pattern, and adjusting the layout pattern by moving the vertices of the polygon to generate a next iteration of the layout pattern. The method includes continuing the adjusting, projecting, and determining until a criterion is satisfied and a final iteration of the layout pattern of the opening is generated.