Line edge and width roughness smoothing by plasma treatment

Smoothing effects of post-litho plasma treatment on 22nm lines and spaces are evaluated for two types of EUV photo resists. This paper shows that different plasma conditions will be required to obtain a similar or better roughness reduction as previously reported for 30 nm lines. A first screening indicates a reduction in LWR of about 10% by using a H2 plasma smoothing process. This smoothing is mainly triggered by the synergy of H2 radical and ionic species during plasma treatment. Moreover the smoothing process is highly dependent on the polymer chemistry.