Evaluation of the CD-SEM Vistec LWM90xx for line-width measurement of nanoimprint templates

In the UV-NIL template fabrication sequence usually four 65×65mm 2 templates are fabricated at once using a 6025 mask blank. After finishing all patterning processes and the etching of the imprint pedestals the templates are separated by dicing and polishing. This technique offers the advantage to use standard mask tools for the majority of the production steps. In order to check the imprint pattern on the mask CD measurements of quartz features are necessary. To control the fabrication process more effectively the additional measurement of resist features would be helpful. When the template is used for imprinting, repeated cycles of anti-adhesion layer deposition and cleaning after multiple imprints might change the CD of the quartz features. The metrology steps have to be performed on 1X features and are therefore more challenging, compared to those for 4X photomasks. For this purpose we evaluated the capability of Vistec's CDSEM LWM90xx for line-width measurements of nanoimprint templates. After optimization of hardware and software settings, the measurement capability for different feature sizes has been characterized. Finally, the evaluated results have been compared with the ITRS requirements for the 22nm node in order to address possible future needs.