Chiral Nematic Fluids as Dynamic Masks for Lithography

Abstract

The use of tunable and self-assembled structures such as block copolymers and colloids as lithography mask has attracted considerable attention in recent years because the techniques involved are cost-effective and provide versatile route to the fabrication of nano-scaled patterns. Here, we introduce new concept of very simple lihography using periodic cholesteric liquid crystals (CLCs) texture act as a photomask in forming repetitive and uniform patterns in photoresist over large area. Unlike conventional photomask, the technique fabricating CLC mask is very simple, inexpensive and versatile. We demonstrate that homogeneous arrays of CLCs with its helix in plane (fingerprint texture) under electric field act as a lens to generate periodic light intensity on photoresist. Based on observation by atomic force microscope and optical microscope, we found that the distribution and shape of patterns in photoresist successfully replicates the distribution and shape of the CLCs.