<i>In situ</i> real time process characterization in nanoimprint lithography using time-resolved diffractive scatterometry

Abstract

To optimize nanoimprint lithography (NIL), it is essential to be able to characterize and control the NIL process in situ and in real time. Here, we present a method for in situ real-time NIL process characterization using time-resolved diffractive scatterometry (TRDS). A surface relief diffraction grating is used as the imprint mold, and the diffracted light intensity is monitored continuously during the imprint process. We use a scalar diffraction model to calculate the diffraction intensity as a function of the mold penetration ratio. Simulations show good agreement with the experimental results. Our results indicate that TRDS offers a powerful characterization tool that can be used for in situ, real-time NIL process control.