Accurate Location and Manipulation of Nano-Scaled Objects Buried under Spin-Coated Films

Abstract: Detection and precise localization of nano-scale structures buried beneath spin coated films are highly valuable additions to nano-fabrication technology. In principle, the topography of the final film contains information about the location of the buried features. However, it is generally believed that the relation is masked by flow effects, which lead to an upstream shift of the dry film's topography and render precise localization impossible. Here we demonstrate, theoretically and experimentally, that the flow-shift paradigm does not apply at the sub-micron scale. Specifically, we show that the resist topography is accurately obtained from a convolution operation with a symmetric Gaussian Kernel whose parameters solely depend on the resist characteristics. We exploit this finding for a 3 nm precise overlay fabrication of metal contacts to an InAs nanowire with a diameter of 27 nm using thermal scanning probe lithography.