Provided herein are methods and related apparatus that facilitate patterning by performing highly non-conformal (directional) deposition on patterned structures. The methods involve depositing films on a patterned structure, such as a hard mask. The deposition may be both substrate-selective such that the films have high etch selectivity with respect to an underlying material to be etched and pattern-selective such that the films are directionally deposited to replicate the pattern of the patterned structure. In some embodiments, the deposition is performed in the same chamber as a subsequent etch is performed. In some embodiments, the deposition may be performed in a separate chamber (e.g., a PECVD deposition chamber) that is connected to the etch chamber by a vacuum transfer chamber. The deposition may be performed prior to or at selected intermittences during at etch process. In some embodiments, the deposition involves multiple cycles of a deposition and treatment process.