Characterizing macroscopic lateral distortion in nanoimprint lithography using moiré interferometry

Distortion in nanoimprint lithography (NIL) can be well checked using various microscopes in a microscale region, but it is difficult to complete wafer-level/macroscopic distortion testing. As an alternative solution to the above issue, we apply moiré interferometry to characterize the macroscopic lateral distortion in NIL by detecting the strain between the stamp and its duplication. With a self-developed moiré interferometry system, distortion can be directly visualized by the fringe pattern with a field of view on the centimeter scale, which is not possible employing other methods. The proposed method is verified in two typical experiments and is shown to be a powerful tool for the characterization of distortion induced in NIL. The method is able to locate the position and affected zone of a defect in a grating structure rapidly and simultaneously.