Nanoimprint Lithography Processing of Inorganic-Based Materials

Abstract

We review past and recent progress in Nano-Imprint Lithography (NIL) methods to (nano-) structure inorganic materials from sol-gel liquid formulations and colloidal suspensions onto a surface. This technique, first inspired by embossing techniques, was developed for soft polymer processing, as final or intermediate materials, but is today fully adapted to hard inorganic materials with high dielectric constant, such as metal oxides, with countless chemical compositions provided by the sol-gel chemistry. Consequently, NIL has become a versatile, high throughput, and highly precise microfabrication method that is mature for lab developments and scaling up. We first describe the state-of-the-art in nanofabrication methods and the plethora of approaches developed in the last decades to imprint metal oxides from inorganic solutions. These are discussed and compared in terms of performances, issues, and ease of implementation. The final part is devoted to relevant applications in domains of interest. Generalities on Nano fabrication techniques and NILFrom the early ages, technics to cut, sculpt, etch, mold, assemble pieces of matter have been developed and constantly optimized to satisfy the growing demand for functional materials. Since the inception of nanotechnology, these operations have to be mastered at the nanoscale. For these tasks, many top-down and bottom-up methods exist. However, they do not simultaneously fulfill all the necessary criteria of performance such as spatial resolution, pattern complexity, hierarchy, scalability, dimensionality, costeffectiveness, a span of processable materials. Thus, motivations to optimize them and develop new ones persist as a flourishing domain of research and development.Many materials exhibiting various intrinsic properties (mechanical, chemical, electrical, optical, thermal, etc.) are exploited in numberless functions once nanostructured onto a surface. Amongst them, metal oxides are extremely valuable for their extreme chemical, mechanical and thermal stability and range of physicalchemical properties. Thanks to its hardness, chemical inertness, transparency and low background fluorescence, glass is one of the preferred choices for micro-and nano-fluidics device fabrication. In photonics, metasurfaces require optical properties that are found in dielectrics such as SiO2 often combined with high index dielectric TiO2 or (plasmonic) gold 1 . For nano-electronics, silica remains one of the key

Solution-Driven Imprinting Lithography of Sol–Gel ZnO Thin Films for Liquid Crystal Display

“…Recently, h-PDMS with high modulus or h-PDMS/conventional PDMS composites have been used to imprint lithography for more precise control . However, We used the conventional soft PDMS with low modulus.…”

“…Recently, h-PDMS with high modulus or h-PDMS/conventional PDMS composites have been used to imprint lithography for more precise control. 27 However, We used the conventional soft PDMS with low modulus. The conventional soft PDMS is enough to imprint the nano structure for LCD because the width and height sizes of the pattern for an alignment layer are to be above 100 nm.…”

Conductive Materials with Elaborate Micro/Nanostructures for Bioelectronics

“…Nanoimprint lithography (NIL) is another technique to fabricate materials with nanoscale features. [90][91][92] Similarly with the lithography technology mentioned above, pre-prepared masks are fixed on the resist layer to first form patterns, as demonstrated in Figure 3e. [83] Nowadays, NIL has been proven to fabricate nanogaps with parallel grating lines at the scale of around sub-10 nm.…”

Recent advances in engineering nanotopographic substrates for cell studies

“…The transfer of the nanopattern can be conducted in several ways: by thermocompression using high temperatures to soften the polymer resist while pressing it with the stamp, also known as hot embossing lithography, or by using UV light to cross-link and harden a soft polymer resist during the imprint (UV-NIL). UV-NIL requires the substrate and/or stamp to be transparent to UV wavelengths ( Modaresialam et al, 2021 ).…”