Design and fabrication of novel and functional 3D structures via proximity field nano-patterning

Proximity field Nano-Patterning (PnP) is a large-area interference lithography technique that is used to fabricate multi-dimensionally periodic micro-structures. Though a potent technique for 3D microfabrication that offers dual and superior advantage of scalable resolution and throughput, this technique has not seen broader adoption due to the lack of concerted design and fabrication strategies that would enable the ability to target, design for and fabricate functional structures. This work endeavors to address this critical gap. A broad genetic algorithm based inverse design technique is developed that allows the ability to design PnP experiments that can target any arbitrary structure. Furthermore, the technique of enhanced PnP (ePnP) and nano-indentation PnP (NI-PnP) are developed and demonstrated. ePnP serves to improve to address the gap between the different aspects of fabricability associated with a PnP design. NI-PnP is used as a method of fabricating gratings with multiple levels and/or complex topologies as an alternative to the more common bilevel gratings that are used as diffractive optical elements (DOE) for PnP. This move results in a significantly expanded 3D structure motif design space that can be exploited with the genetic algorithm based inverse design approach. Finally, PnP is used to demonstrate the fabrication of high quality chiral structures with sub-micron pitches – the first demonstration of chiral structures via PnP and the first repeatable demonstration with any form of interference lithography