17 April 2017
While direct grayscale writing is one of the key benefits of NanoFrazor lithography, the shape of the NanoFrazor tip limits the achievable patterning depth in the resist. However, when the application requires deeper structures than can be written, the pattern can be amplified during the pattern transfer step. A new joint paper by EPFL and SwissLitho investigates a combination of NanoFrazor patterning and pattern amplification by dry etching. Remarkably, the patterns can be amplified by a factor of up to 100 by using an oxide hard mask intermediate layer below the resist. An etch depth of up to 4 micrometers in silicon was achieved while retaining good pattern fidelity and low surface roughness. More details can be found here. The project 3DNano2Micro is a collaboration between SwissLitho and EPFL and supported by the Commission for Technology and Innovation (CTI) of Switzerland.
Y. Lisunova et al., High-aspect ratio nanopatterning via combined thermal scanning probe lithography and dry etching, Microelectronic Engineering (preprint), http://doi.org/10.1016/j.mee.2017.04.006