As the semiconductor industry pursues Moore's law, the demand to obtain smaller features continues. Extreme ultraviolet (EUV) lithography remains one of the primary options for sub‐20 nm patterns. However, the technology struggles to meet the line width roughness (LWR) specifications. In this article, we present the significance of plasma treatment as a roughness smoothing technique. Two EUV photoresists with 22 nm lines are exposed to various plasma processes. We highlight the advantages of a hydrogen plasma treatment and its vacuum ultraviolet (VUV) emission as an optimal smoothing process and discuss the effect of photoresist thickness, initial LWR and the VUV plasma emission. Even though a H2 plasma treatment results in a successful reduction of LWR/LER, the target value of below 2nm is not yet achieved.

To meet the demands for sub‐20 nm feature devices in the semiconductor industry, minimizing the line width roughness (LWR) is a critical concern for ultra‐large scale integrated circuit manufacturing. Post‐lithography treatments should reduce the LWR by at least 50% to meet the technology requirements, but the available post‐lithography strategies come short. To support the delayed progress, an in depth understanding of the interaction of such post‐lithography treatments with EUV‐specific resist functionalities is required. In this article, we analyze the change in line widths and LWR's for 30–35 nm lines using EUV photoresists. In addition we study the effect of the chemical composition on the reduction of LWR after hydrogen plasma treatment using “artificially” prepared reference resists. We highlight the effect of the fluorine unit, ester functionalities and photo acid generator/quencher loading on the LWR improvement and H2 plasma induced reflow.