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 the 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 applied 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 the field alignment by the metal mask for the etching (FAME)
process, we demonstrate the fabrication of 378 nm-size nanostructure
patterns which translate 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 that it enables the
functionality of FAME-processed nanostructures.