Feasibility of Atomic Layer Etching of Polymer Material Based on Sequential O2 Exposure and Ar Low-Pressure Plasma-Etching

We describe controlled, self-limited etching of a polystyrene polymer using a composite etching cycle consisting of sequential deposition of a thin reactive layer from precursors produced from a polymer-coated electrode within the etching chamber, modification using O₂ exposure, and subsequent low-pressure Ar plasma etching, which removes the oxygen-modified deposited reactive layer along with ≈0.1 nm unmodified polymer. Deposition prevents net etching of the unmodified polymer during the etching step and enables self-limited etch rates of 0.1 nm/cycle.