Design and fabrication of multi-aperture plate for multi-ion beam patterning system

For the multi-ion beam patterning system, it is necessary to develop a multi-aperture plate with a beam-controllable aperture device for individual adjustment of multi-ion beams on the stage. It is important to select the appropriate material for the multi-aperture plate to confirm the durability against damage by ion beams since the multi-aperture is located under a relatively strong ion beam. To prepare the controllable aperture system on the bottom side of the multi-aperture plate, the materials must be suitable for the microfabrication process. From an experimental etching test of some candidate materials, a silicon substrate with a magnesium oxide coating was selected for the multi-aperture plate. The structure also includes a Mo mesh on the top surface to solve the surface charging problem caused by ion beams, resulting in improved ion beam penetration through the aperture. Finally, a beam-controllable aperture device was designed with embedded parallel electrodes for durable and stable beam control and fabricated by the silicon microfabrication process.