Nanoimprint Lithography - the Past, the Present and the Future

Background: Nanoimprinting lithography technique uses a very simple concept of transferring pattern of nanoscale features from a mold to a target substrate. In the past two decades, this technique has successfully broken through the barrier of laboratory scale production and become an industrial scale production technique. The aim of this paper is to introduce to readers to the basic working principle, applications, analysis the technological limitations. It will also point out future research direction of this useful nanofabrication technique. Methods: We adopted a systematic approach to give a comprehensive review of the work principle, hardware and analysis of advantaged and disadvantages of major nanoimprint lithography techniques. Moreover, a technical comparison of these methods is carried out to provide future research direction. Results: 87 papers were reviewed. Four techniques including thermal NIL, ultraviolet light NIL, laser-assisted direct imprint and nanoelectrode lithography have been identified as main stream of NIL techniques. These techniques possess certain advantages and disadvantages in terms of cost, throughput, attainable resolution. Lack of flexibility is the common limitation of current NIL techniques. NIL has gained wide applications in the fabrication of optoelectronics devices, solar cells, memory devices, nanoscale cells, hydrophobic surfaces and bio-sensors. The potential applications of NIL in biochips, artificial organs, diagnostic system, and fundamental research in cell biology will demand large scale 3D fabrication capability with resolution towards 10nm or less. Conclusions: The findings of this review confirm that NIL is one of the most employed commercial platforms for nanofabrication which offers high throughput and cost-effectiveness. One of the disadvantages of NIL over other nanofabrication techniques is the flexibility of patterning. Integrating NIL with other existing nanofabrication techniques can be helpful to overcome such issue. The potential applications of NIL in biochips, artificial organs, diagnostic system, and fundamental research in cell biology will attract researchers to push nanoimprint lithography forward at a resolution of 10 nm or less in the future. Keywords: Nanofabrication, nanoimprint lithography, resolution, roll-to-roll, throughput.