A method of treating resist features comprises positioning, in a process chamber, a substrate having a set of patterned resist features on a first side of the substrate and generating a plasma in the process chamber having a plasma sheath adjacent to the first side of the substrate. The method may further comprise modifying a shape of a boundary between the plasma and the plasma sheath with a plasma sheath modifier so that a portion of the shape of the boundary is not parallel to a plane defined by a front surface of the substrate facing the plasma, wherein ions from the plasma impinge on the patterned resist features over a wide angular range during a first exposure.