A method for enhancing the depth of focus process window during a lithography process includes applying a photoresist layer comprising a photoacid generator on a material layer disposed on a substrate, exposing a first portion of the photoresist layer unprotected by a photomask to light radiation in a lithographic exposure process, providing a thermal energy to the photoresist layer in a post-exposure baking process, applying an electric field or a magnetic field while performing the post-exposure baking process, and dynamically changing a frequency of the electric field as generated while providing the thermal energy to the photoresist layer.