  Laser polymerization has emerged as a direct writing technique allowing the
fabrication of complex 3D structures with microscale resolution. The technique
provides rapid prototyping capabilities for a broad range of applications, but
to meet the growing interest in 3D nanoscale structures the resolution limits
need to be pushed beyond the 100 nm benchmark, which is challenging in
practical implementations. As a possible path towards this goal, a post
processing of laser polymerized structures is presented. Precise control of the
cross-sectional dimensions of structural elements as well as tuning of an
overall size of the entire 3D structure was achieved by combining isotropic
plasma etching and pyrolysis. The smallest obtainable feature sizes are mostly
limited by the mechanical properties of the polymerized resist and the geometry
of 3D structure. Thus the demonstrated post processing steps open new avenues
to explore free form 3D structures at the nanoscale.
