A method of printing a pattern having vertically oriented features and
horizontally oriented features on a substrate utilizing dipole
illumination, which includes the steps of: identifying background areas
contained in the pattern; generating a vertical component mask comprising
non-resolvable horizontally oriented features in the background areas;
generating a horizontal component mask comprising non-resolvable
vertically oriented features in the background areas; illuminating said
vertical component mask utilizing an X-pole illumination; and
illuminating said horizontal component mask utilizing a Y-pole
illumination.