In this paper, we conduct a comprehensive comparative study of next-generation lithography (NGL) processes
in terms of their line width roughness (LWR) performance. We investigate mainstream lithography options
such as double patterning lithography (DPL), self-aligned double patterning (SADP), and extreme ultra-violet
(EUV), as well as alternatives such as directed self-assembly (DSA) and nano-imprint lithography (NIL). Given
the distinctly different processing steps, LWR arises from different sources for these patterning methods, and a
unified, universally applicable set of metrics must be chosen for useful comparisons. For each NGL, we evaluate
the LWR performance in terms of three descriptors, namely, the variation in RMS amplitude (σ), correlation
length (see manuscript) and the roughness exponent (α).
The correlation length (which indicates the distance along the edge beyond which any two linewidth measurements
can be considered independent) for NGL processes is found to range from 8 to 24 nm. It has been
observed that LWR decreases when transferred from resist into the final substrate and all NGL technology options
produce < 5% final LWR. We also compare our results with 2008 ITRS roadmap. Additionally, for the
first time, spatial frequency transfer characteristics for DSA and SADP are being reported. Based on our study,
the roughness exponent (which corresponds to local smoothness) is found to range from ~0.75-0.98; it is close to
being ideal (α = 1) for DSA. Lastly using EUV as an example, we show the importance of process optimization
as these technologies mature.