Method of locating sub-resolution assist feature(s)

A method of operating a computing system to determine reticle data, the reticle data for completing a reticle for use in projecting an image to a semiconductor wafer, the method comprising:

• receiving circuit design layer data comprising a desired circuit layer layout, the layout comprising a plurality of lines;
• identifying in the plurality of lines a first line portion for use as a first circuit function and a second line portion for use as a second circuit function that differs from the first circuit function, the first line portion being parallel and adjacent to the second line portion;
• and
• generating the reticle data in an output data file for use in forming features on the reticle, the generating step comprising:
• indicating a location on the reticle where a first primary feature is to be formed, the first primary feature corresponding to the first line portion;
• indicating a location on the reticle where a second primary feature is to be formed, the second primary feature corresponding to the second line portion;
• and
• indicating parameters for forming at least one assist feature on the reticle comprising indicating an asymmetric location of the at least one assist feature on the reticle between the first primary feature and the second primary feature, wherein in use of the reticle for use-in projecting the image to the semiconductor wafer, positioning of the at least one assist feature favors the first primary feature as compared to the second primary feature.