Week 10 : Nanofabrication through Nanoimprint Lithography
The Nanoimprint lithography (NIL) is a novel method of fabricating micro/nanometer scale patterns with low cost, high throughput and high resolution down to sub -10 nm. Unlike traditionally optical lithographic approaches, which create pattern through the use of photons or electrons to modify the chemical and physical properties of the resist, NIL relies on direct mechanical deformation of the resist and can therefore achieve resolutions beyond the limitations set by light diffraction or beam scattering that are encountered in conventional lithographic techniques .
The resolution of NIL mainly depends on the minimum template or mold feature size that can be fabricated. In addition, nanometer sized patterns can easily be formed on various substrates, e.g., silicon wafers, glass plates, flexible polymer films, and even nonplanar substrates. Since the first demonstration of NIL in the mid 1990s, patterned magnetic media for harddisk drives (HDDs) has been a key application. Nanoimprint providers and their users are also focusing on the high-density memory, such as NAND flash. NIL can be used as a most effective patterning tool to fabricate high density photonic crystals for high efficiency and low cost LED devices. Rapid progress is being made to reach manufacturing quality and cost targets suitable for high volume LED manufacturing.
However, many challenges in implementation of nanoimprinting technology into patterned media disk fabrication process still abound, such as choice of nanoimprinting resist, pattern transfer fidelity and uniformity, and lifetime of master stamp.