A method of patterning a substrate. The method may include: providing a first surface feature and a second surface feature in a staggered configuration within a layer, the layer being disposed on the substrate, and directing first ions in a first exposure to a first side of the first surface feature and a first side of the second surface feature, in a presence of a reactive ambient containing a reactive species, wherein the first exposure etches the first side of the first surface feature and the first side of the second surface feature, wherein after the directing, the first surface feature and the second surface feature merge to form a third surface feature.