A method for etching an etch layer formed on a substrate is provided. A first photoresist (PR) mask with first mask features is provided on the etch layer. A protective coating is provided on the first PR mask by a process including at least one cycle. Each cycle includes (a) a deposition phase for depositing a deposition layer over the surface of the first mask features using a deposition gas, and (b) a profile shaping phase for shaping the profile of the deposition layer using a profile shaping gas. A liquid PR material is applied over the first PR mask having the protective coating. The PR material is patterned into a second mask features, where the first and second mask features form a second PR mask. The etch layer is etched though the second PR mask.