In situ UV nano-imprint lithography alignment using high contrast mark

This paper focuses on designing and fabricating high contrast alignment marks used for UV imprint lithography in situ alignment. Since the imprint resist filled in the imprint pattern will deteriorate the intensity and contrast of the Moiré fringes, it's hard to perform alignment based on the Moiré image. Simulations based on rigorous coupled-wave analysis (RCWA) are performed to design and optimize the high contrast alignment mark in order to obtain high quality Moiré fringes. Designed high contrast mark is fabricated and tested on imprint alignment system. Experiments demonstrated that the simulation results are correct and feasible.