Large Area, Facile Oxide Nanofabrication via Step-and-Flash Imprint Lithography of Metal–Organic Hybrid Resins

Abstract

Step-and-flash imprint lithography (S-FIL) is a wafer-scale, high-resolution nanoimprint technique capable of expansion of nanoscale patterns via serial patterning of imprint fields. While S-FIL patterning of organic resins is well known, patterning of metal-organic resins followed by calcination to form structured oxide films remains relatively unexplored. However, with calcination shrinkage, there is tremendous potential utility in easing accessibility of arbitrary nanostructures at 20 nm resolution and below. However, barriers to commercial adoption exist due to difficulties in formulating polymerizable oxide precursors with good dispensability, long shelf life, and resistance to auto-homopolymerization. Here we propose a solution to these issues in the form of a versatile resin formulation scheme that is applicable to a host of functional oxides (Al2O3, HfO2, TiO2, ZrO2, Ta2O5, and Nb2O5). This scheme utilizes a reaction of metal alkoxides with 2-(methacryloyloxy)ethyl acetoacetate (MAEAA), a polymerizable chelating agent. Formation of these inorganic coordination complexes enables remarkable resistance to auto-homopolymerization, greatly improving dispensability and shelf life, thus enabling full scale-up of this facile nanofabrication approach. Results include successively imprinted fields consisting of 100 nm linewidth gratings. Isothermal calcination of these structures resulted in corresponding shrinkage of 75-80% without loss of mechanical integrity or aspect ratio, resulting in 20 nm linewidth oxide nanostructures.

Oxygen insensitive thiol–ene photo-click chemistry for direct imprint lithography of oxides

“…This approach has been found to harness the advantages and obviates the limitations of the conventional sol-gel approach. The PSG approach has been shown to be suitable for high-throughput step-and-ash imprint lithography for various oxides 55 and to synthesize supported oxide photo-catalysts. 56,57 Despite the high potential, the PSG approach based on free radical polymerization of methacrylates is vulnerable to radical scavenging by oxygen that could affect the degree of polymerization, which in turn could effect on the quality of imprinting.…”

Multiscale Ommatidial Arrays with Broadband and Omnidirectional Antireflection and Antifogging Properties by Sacrificial Layer Mediated Nanoimprinting

“…Nanoimprinting or nanoimprint lithography (NIL) is a simple pattern transfer technique, widely used to fabricate nanostructure patterns on various planar substrates. [27][28][29][30] It basically involves transfer of surface reliefs from a template to a thin-film by embossing at an optimum combination of temperature and pressure. Furthermore, NIL offers a very good resolution with relatively faster replication and has proven to be economical.…”

Tunable daughter molds from a single Si master grating mold

“…[29][30][31] Calcination at high temperature ensured that the organic content in SiO 2 resin is entirely decomposed. The imprinted structures are subsequently calcined to achieve oxide patterns.…”