Methods and apparatuses for minimizing line edge/width roughness in lines formed by photolithography are provided. The random diffusion of acid generated by a photoacid generator during a lithography process contributes to line edge/width roughness. Methods disclosed herein apply an electric field and/or a magnetic field during photolithography processes. The field application controls the diffusion of the acids generated by the photoacid generator along the line and spacing direction, preventing the line edge/width roughness that results from random diffusion. Apparatuses for carrying out the aforementioned methods are also disclosed herein.