Misalignment sensing with a moiré beat signal for nanolithography

Our group proposes an improved misalignment measurement scheme using the moiré beat signal. Compared with the coarse-fine moiré-based alignment methods, this scheme could complete the nanometer-scale alignment within a centimeter-scale scope in one step. Moreover, it could also fundamentally eliminate the influence from the field of view of the observation lens. These merits make it suitable for the high-precision large-scope misalignment sensing in the proximity, x-ray, and nanoimprint lithographies. The experimental results are given to verify the feasibility and rationality.