Simulation of nano-grating patterning based on X-ray Talbot effect

High aspect ratio gratings can be made by perpendicularly cutting in the growth direction of multilayers. X-ray exposure technique using a sectioned multilayer grating based on Talbot effect is a new type of nano patterning method. Although 300 nanometers gratings through the experiment were completed, some phenomena in their experiments cannot be satisfactorily explained and factors influencing the nano pattern quality haven’t been fully understood. Here we use rigorous coupled-wave theory to discuss several important factors, including grating thickness, ratio of material thickness and multilayer period, which is the first time for Talbot self-imaging in x-ray range. The simulation results show that grating thickness affects both x-ray transmission efficiency and fringe contrast, while ratio of material thickness determines quality of fringes. And the position deviation of the best image plane in near field is related to both the thickness of gratings and multilayer period. Moreover, the multilayer gratings with smaller period can achieve higher resolution, which indicates that Talbot effect can be used to fabricate more detailed structure.