An Innovative Method for Uniform Pattern Transfer in Nanoimprint

Nanoimprint has the advantages of high throughput, sub-10-nm feature and low cost. However, the uniformity is a major concern of the pattern transfer fidelity across large area. In this study, the authors present a method for uniform printing by introducing a designed local mold deformation along the block boundary. This method is simple and effective. The shallow grooves are cut on the back of the mold along the boundaries defining the blocks of patterned features. The grooves absorb the most mold deformation and enable each block to lie on the substrate with close fit to obtain uniform pattern transfer over a large area. Both simulation and experimental investigations are conducted to verify the proposed approach. The results reveal that increasing the imprinting pressure will cause large mold deformation and affect the imprinted quality significantly. The method of cutting grooves can reduce the imprint defects and increase the uniformity in the patterned area. Using the proposed technique to fabricate 50 nm grates with the aspect ratio as high as 4 is proved successful. The results demonstrate a new imprint method of introducing the controlled local mold deformation for uniform imprint across large area.