Wafer-Level Self-Organized Copolymer Templates for Nanolithography with Sub-50 nm Feature and Spatial Resolutions

Abstract

Robust lithographic templates, with sub-50 nm feature and spatial resolutions, that exhibit high patterning integrity across a full-wafer are demonstrated using self-organized copolymer reverse micelles on 100 mm Si wafers. A variation of less than 5% in the feature size and periodicity of polymeric templates across the entire wafer is achieved simply by controlling the spin-coating process. Lithographic pattern transfer using these templates yields Si nanopillar arrays spanning the entire wafer surface and exhibiting high uniformity inherited from the original templates. The variation in geometric characteristics of the pillar arrays across the full-wafer surface is validated to be less than 5% using reflectance spectroscopy. The physical basis of the change in reflectance with respect to sub-10 nm variations in geometric parameters of pillar arrays is shown by theoretical modelling and simulations. Successful fabrication of highly durable TiO₂ masks for nanolithography with sub-50 nm feature width and spatial resolutions is achieved through highly controlled vapour phase processing of reverse micelle templates. This allows lithographic pattern-transfer of organic templates with a feature thickness and separation of less than 10 nm, which is otherwise not possible through other approaches reported in literature.