[Granted] A computer readable storage medium containing program instructions for treating a photoresist relief feature on a substrate having an initial line roughness and an initial critical dimension, that, when executed cause a system to: direct ions toward the photoresist relief feature in a first exposure at a first angular range and at a first ion dose rate configured to reduce the initial line roughness to a second line roughness; and direct ions toward the photoresist relief feature in a second exposure at a second ion dose rate greater than the first ion dose rate, the second ion dose rate being configured to swell the photoresist relief feature.