LAUSR

Recently, researchers have dedicated efforts toward producing large-area nanostructures using advanced lithography techniques and state-of-the-art etching methods. However, these processes involve challenges such as the diffraction limit and an unintended etching profile. In this work, we demonstrate large-area nanopatterning on a silicon substrate using a microscale metal mask by meticulous optimization of the etching process. Around the vertex of a microscale metal mask, a locally induced electric field is generated by a bias voltage on a silicon mold. We utilize this field to change the trajectory of reactive ions and their effect flux, thus providing a controllable bowing effect. The results are analyzed by both numerical simulations and experiments. Based on this field alignment by metal mask for etching (FAME) process, we demonstrate the fabrication of 378-nm size nanostructure patterns which translates to a size reduction of 63% from 1-μm size mask patterns on a wafer by optimization of the processes. This is much higher than the undercut (~37%) usually achieved by a typical non-Bosch process under similar etching conditions. The optimized nanostructure is used as a mold for the transfer printing of nanostructure arrays on a flexible substrate to demonstrate enabling the functionality of FAME-processed nanostructures.