Semiconductor devices and methods which utilize a treatment process of a bottom anti-reflective layer are provided. The treatment process may be a physical treatment process in which material is added in order to fill holes and pores within the material of the bottom anti-reflective layer or else the treatment process may be a chemical treatment process in which a chemical reaction is used to form a protective layer. By treating the bottom anti-reflective layer the diffusion of subsequently applied chemicals is reduced or eliminated, thereby helping to prevent defects that arise from such diffusion.