Copyright 2017 EPFL
Yuliya Lisunova and co-authors have presented their publication entitled "High-aspect ratio nanopatterning via combined thermal scanning probe lithography and dry etching" in Microelectronic Engineering.
Thermal scanning probe lithography is considered to be an advancing nanofabrication technique capable of performing rapid prototyping of arbitrary topographies in thermally sensitive resist. This feature, combined with the latest advances in dry plasma etching techniques, allows the fabrication of high-resolution nanopatterns in hard substrates. Here, the key process parameters are analyzed in order to allow the fabrication of high aspect ratio nanopatterns in silicon. The authors amplified the shallow resist patterns by a factor of 100 into the silicon substrate by a combination of resist heat treatment, optimized etch parameters and the use of a hard mask during pattern transfer. This helps maintaining vertical sidewalls and low surface roughness. The authors demonstrate the fabrication of 240 nm wide lines and 4 μm deep single crystal silicon patterns.