Evaluation of Line Edge Roughness in Nanoimprint Lithography Using Photocurable Polymer

To evaluate the ultimate accuracy in nanoimprint replication using photocurable resin, we studied the line edge roughness (LER) of replicated patterns using a mold pattern on a Si (110) substrate produced by anisotropic wet etching. The root mean square (RMS) for the replicated pattern LER was between 0.64 nm and 0.9 nm. This was slightly larger than that for the mold pattern. The RMS for the mold pattern was between 0.48 nm and 0.62 nm. The replicated pattern RMS shows no systematic change when the ultraviolet light exposure dose is increased from 10 mJ/cm2 to 3 J/cm2. Based on the dependence of the RMS for both of the line edge and Ti coated resin surface, we concluded that the increment of the RMS in the replicated pattern is due to the Ti coating which was carried out for scanning electron microscope observation of the replicated pattern.