Application of analytic SEM to CD metrology at nanometer scale

SEM metrology involves uncertainty of the linewidth measurement because the SEM signal formation is an extremely complex process. In this work, we used an analytical SEM for CD metrology applications on quartz nanoimprint template. The SEM was tuned first to find the best reasonable condition for consistent operation. Beam characterization was done using BEAMETR beam measurement technique. SEM images of templates were taken at optimum conditions. The measurements were done using a) regular imaging processing software and b) using physical model based processing tool myCD. The quartz template was then measured using TEM crossections at selected sites to reveal profile information as metrology comparison reference. The metrology capability and fundamental limitation of analytical SEM operation with regular imaging processing was identified. Information about SEM setup and materials was used. The considerable improvement using the physical modeling imaging process was found.