High-throughput Nanoimprint Lithography Research Articles

Highly Effective Index-Matching Antireflective Structures for Polymer Optics

Optical polymers are attractive for lightweight and cost-effective refractive optical components, yet they reflect part of the incident light. Traditional vacuum-deposited antireflective films purely adhere to polymers and suffer from mechanical stresses due to the difference in the thermal expansion coefficients. Alternatively, reflection can be reduced by moth-eye structures; yet, their efficiency strongly depends on their index-matching with the optical substrate, which has not been demonstrated so far. Here, we introduce a new approach to engineering highly effective antireflective structures on the surface of the optical polymer, with an unprecedented ability to reduce the surface reflection from 5 to 0.1%. The structures were produced by high-throughput nanoimprint lithography, and their superior optical performance was achieved due to the precise matching of their index to that of the underlying substrate. We further applied these structures on different polymers and showed that their antireflective effect correlates with index-matching. We demonstrated that these structures could be applied on flat surfaces and curved lenses and produce high surface hydrophobicity. Overall, our work paves the way to an efficient and scalable antireflective solution for polymer optics.

Nanoimprint Lithography-Directed Self-Assembly of Bimetallic Iron-M (M=Palladium, Platinum) Complexes for Magnetic Patterning.

Self-assembly of d8 metal polypyridine systems is a well-established approach for the creation of 1D organometallic assemblies but there are still challenges for the large-scale construction of nanostructured patterns from these building blocks. We describe herein the use of high-throughput nanoimprint lithography (NIL) to direct the self-assembly of the bimetallic complexes [4'-ferrocenyl-(2,2':6',2''-terpyridine)M(OAc)]+ (OAc)- (M=Pd or Pt; OAc=acetate). Uniform nanorods are fabricated from the molecular self-organization and evidenced by morphological characterization. More importantly, when top-down NIL is coupled with the bottom-up self-assembly of the organometallic building blocks, regular arrays of nanorods can be accessed and the patterns can be controlled by changing the lithographic stamp, where the mold imposes a confinement effect on the nanorod growth. In addition, patterns consisting of the products formed after pyrolysis are studied. The resulting arrays of ferromagnetic FeM alloy nanorods suggest promising potential for the scalable production of ordered magnetic arrays and fabrication of magnetic bit-patterned media.

Nanopatterned L10-FePt nanoparticles from single-source metallopolymer precursors for potential application in ferromagnetic bit-patterned media magnetic recording

A new single-source metallopolymer precursor P was applied for the synthesis of magnetic FePt nanoparticles, which was also suitable for patterning by high-throughput nanoimprint lithography to obtain ferromagnetic nanolines.

Fabrication and Recording of Bit Patterned Media Prepared by Rotary Stage Electron Beam Lithography

Bit patterned media (BPM) is a promising technology for hard disk drive recording at ultra-high areal densities of 1 Tbit/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and beyond. However, for BPM to be commercially viable, nanoscale bit patterns must be fabricated at low cost on a large scale and with low defect densities. The most likely route to realizing such criteria is through the use of high throughput nanoimprint lithography followed by direct etching of the recording media, where the bit pattern template is generated by highly accurate electron beam mastering tools. In this work, we experimentally demonstrate the merits of rotary stage electron beam mastering and the subsequent effects of direct pattern transfer on BPM and servo arrays patterned into 2.5" commercially available CoCrPt perpendicular recording media (PRM) at a density of 366 Gbit/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The 42 nm pitch staggered bit patterns and corresponding servo arrays were lithographically generated by a Pioneer Corporation EBR-401 rotary stage electron beam mastering system and subsequently transferred into the media using a series of reactive ion etching and ion milling processes with C/SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> mask structures and a novel Al protection layer. The fabricated media was recorded and read back with a commercial recording head to verify pattern fidelity.

DNA analysis by single molecule stretching in nanofluidic biochips

Stretching single DNA molecules by confinement in nanofluidic channels has attracted a great interest during the last few years as a DNA analysis tool. We have designed and fabricated a sealed micro/nanofluidic device for DNA stretching applications, based on the use of the high throughput NanoImprint Lithography (NIL) technology combined with a conventional anodic bonding of the silicon base and Pyrex cover. Using this chip, we have performed single molecule imaging on a bench-top fluorescent microscope system. Lambda phage DNA was used as a model sample to characterize the chip. Single molecules of λ-DNA stained with the fluorescent dye YOYO-1 were stretched in the nanochannel array and the experimental results were analysed to determine the extension factor of the DNA in the chip and the geometrical average of the nanochannel inner diameter. The determination of the extension ratio of the chip provides a method to determining DNA size. The results of this work prove that the developed fabrication process is a good alternative for the fabrication of single molecule DNA biochips and it allows developing a variety of innovative bio/chemical sensors based on single-molecule DNA sequencing devices.

Roll in and Roll out: A Path to High-Throughput Nanoimprint Lithography

Roller-type nanoimprint lithography is a technique that can potentially increase the throughput of the imprinting process to levels competitive for low-cost, large-area, nanoscale manufacturing. A paper in this issue by Ahn and Guo presents a large-area roll-to-roll and roll-to-plate imprint process that builds on earlier work, increasing the substrate width to 4 in. and transferring patterns of 300 nm width and 600 nm pitch at a rate of 1 m/min.

Design and fabrication using nanoimprint lithography of a nanofluidic device for DNA stretching applications

In this work, we present the design and fabrication of a sealed micro/nanofluidic chip for DNA stretching applications, based on the use of the high-throughput nanoimprint lithography (NIL) technol...

Design and fabrication using nanoimprint lithography of a nanofluidic device for DNA stretching applications

In this work, we present the design and fabrication of a sealed micro/nanofluidic chip for DNA stretching applications, based on the use of the high-throughput nanoimprint lithography (NIL) technology combined with a conventional anodic bonding of the silicon base and Pyrex cover. Using the developed fabrication process sub-100nm width nanochannels have been obtained. The complete chip, including microchannels for fluid transport and nanochannels for DNA stretching and visualization has been fabricated and packaged to facilitate the contact with the macroscopic world.

Direct three-dimensional patterning using nanoimprint lithography

We demonstrated that nanoimprint lithography (NIL) can create three-dimensional patterns, sub-40 nm T-gates, and air-bridge structures, in a single step imprint in polymer and metal by lift-off. A method based on electron beam lithography and reactive ion etching was developed to fabricate NIL molds with three-dimensional protrusions. The low-cost and high-throughput nanoimprint lithography for three-dimensional nanostructures has many significant applications such as monolithic microwave integrated circuits and nanoelectromechanical system.