Methods for performing a lithography process are provided. The method for performing a lithography process includes forming a resist layer over a substrate and exposing a portion of the resist layer to form an exposed portion between unexposed portions. The method for performing a lithography process further includes developing the resist layer to remove the exposed portion of the resist layer such that an opening is formed between the unexposed portions and forming a post treatment coating material in the opening and over the unexposed portions of the resist layer. The method for performing a lithography process further includes reacting a portion of the unexposed portions of the resist layer with the post treatment coating material by performing a post treatment process and removing the post treatment coating material.