Methods for reducing the line width roughness on a photoresist pattern are provided herein. In some embodiments, a method of processing a patterned photoresist layer disposed atop a substrate includes flowing a process gas into a processing volume of a process chamber having the substrate disposed therein; forming a plasma within the process chamber from the process gas, wherein the plasma has a ion energy of about 1 eV to about 10 eV; and etching the patterned photoresist layer with species from the plasma to at least one of smooth a line width roughness of a sidewall of the patterned photoresist layer or remove debris.