  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.
