• Transactions of the Korean Society of Machine Tool Engineers
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• v.18 no.2
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• pp.144-153
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• 2009

It is widely known that no-slip assumptions are often violated on regular basis in micrometer- or nanometer-scale fluid flow. In the case of cavity-filling process of nanoimprint lithography(NIL), slip phenomena take place naturally at the solid-to-liquid boundaries, that is, at the mold-to-polymer or polymer-to-substrate boundaries. If the slip or partial slip phenomena are promoted at the boundaries, the processing time of NIL, especially of thermal-NIL which consumes more tact time than that of UV-NIL, can be significantly improved. In this paper it is aimed to elucidate how the cavity-filling process of NIL can be influenced by the slip phenomena at boundaries and to what degree those phenomena increase the process rate. To do so, computational fluid dynamics(CFD) analysis of cavity filling process has been carried out. Also, the effect of mold pattern shape and initial thickness of polymer resist were considered in the analysis, as well.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.161-162
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• 2006

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.123-124
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• 2008

• Journal of the Microelectronics and Packaging Society
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• v.25 no.1
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• pp.11-15
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• 2018

In this study, we deposited silver nanoparticles on the nanocone array structure which was fabricated by the UV nanoimprint process for optical signal amplification. The deposition of the silver nanoparticles was based on the evaporation behavior of the solution droplet according to wettability of surface and the deposition pattern changed from the center of the droplet to the edge depending on the difference of thermal energy. The optical property of silver nanoparticles that were deposited on imprinted nanohole patterns was simulated by the Finite difference time domain (FDTD) analysis method, and it was confirmed that energy was concentrated around the silver nanoparticle of the finally fabricated structure.

• Journal of the Semiconductor & Display Technology
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• v.10 no.4
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• pp.53-59
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• 2011

Recently there have been considerable attentions on nanoimprint lithography (NIL) by the display device and semiconductor industry due to its potential abilities that enable cost-effective and high-throughput nanofabrication. Although one of the current major research trends of NIL is large-area patterning, the technical difficulties to keep the uniformity of the residual layer become severer as the imprinting area increases more and more. In this paper we focused on the deformation of the $2^{nd}$ generation TFT-LCD sized ($370{\times}470mm^2$) large-area soft mold in the UV imprinting process. A mold was fabricated with PDMS(Poly-dimethyl Siloxane) layered glass back plate(t0.5). Besides, the mold includes large surrounding wall type protrusions of 1.9 mm width and the via-hole(7 ${\mu}m$ diameter) patterend area. The large surrounding wall type protrusions cause the proximity effect which severely degrades the uniformity of residual layer in the via-hole patterend area. Therefore the deformation of the mold was calculated by finite element analysis to assess the effect of large surrounding wall type protrusions and the flexiblity of the mold. The deformation of soft mold was verified by the measurements qualitatively.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.5
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• pp.1-8
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• 2013

Roll-based, nanoimprint lithography (Roll-NIL) is one effective method to produce large-area nanopatterns continuously. Systems and processes for Roll-NIL have been developed and studied for more than 15 years. Since the shapes of the stamp and the substrate for Roll-NIL can be plates, films, and rolls, there exist many concepts to design and implement roll-NIL systems. Combinations and variations of contact-methods for variously shaped stamps and substrates are analyzed in this paper. The contact-area can be changed by using soft materials such as polydimethylsiloxane (PDMS) or silicone rubber. Ultraviolet (UV) sources appropriate for the roll-to-plate or roll-to-roll process are introduced. Finally, two roll-to-plate nanoimprint lithography systems are illustrated.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.12
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• pp.1419-1424
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• 2011

Nanoimprint lithography is a next generation lithography technology, which enables to fabricate nano to micron-scale patterns through simple and low cost process. Nanoimprint lithography has been applied in various industry fields such as light emitting diodes, solar cells and display. Functional patterns, including anti-reflection moth-eye pattern, photonic crystal pattern, fabricated by nanoimprint lithography are used to improve overall efficiency of devices in that fields. For these reasons, in this study, sub-micron-scaled functional patterns were directly fabricated on Si and glass substrates by thermal imprinting process using ZnO nano-particles dispersion resin. Through the thermal imprinting process, arrays of sub-micron-scaled pillar and hole patterns were successfully fabricated on the Si and glass substrates. And then, the topography, components and optical property of the imprinted ZnO nano-particles/resin patterns are characterized by Scanning Electron Microscope, Energy-dispersive X-ray spectroscopy and UV-vis spectrometer, respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.672-675
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• 2005

To imprint 70-nm wide line-patterns, we used a newly developed ultraviolet nanoimprint lithography (UV-NIL) process in which an elementwise patterned stamp (EPS), a large-area stamp, and pressurized air are used to imprint a wafer in a single step. For a single-step UV-NIL of a 4' wafer, we fabricated two identical $5'\times5'\times0.09'(W{\times}L{\times}H)$ quartz EPSs, except that one is with nanopatterns and the other without nanopatterns. Both of them consist of 16 small-area stamps, called elements, each of which is $10\;mm\;\times\;10\;mm$. UV-curable low-viscosity resin droplets were dispensed directly on each element of the EPSs. The volume and viscosity of each droplet are 3.7 nl and 7 cps. Droplets were dispensed in such a way that no air entrapment between elements and wafer occurs. When the droplets were fully pressed between ESP and wafer, some incompletely filled elements were observed because of the topology mismatch between EPS and wafer. To complete those incomplete fillings, pressurized air of 2 bar was applied to the bottom of the wafer for 2 min. Experimental results have shown that nanopatterns of the EPS were successfully transferred to the resin layer on the wafer.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1847-1850
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• 2008

The process conditions during ultraviolet nanoimprint lithography (UV-NIL) process such as temperature, stamping pressure, UV irradiation, etc. are effective factors for successful imprinting of complex and fine patterns. In this study, the effects of aluminum mold on the thermal characteristics of UV-NIL process were investigated through imprinting experiments and numerical simulations. The temperature of polymer resin on mold was measured to study thermal characteristics during UV curing. From the experimental and numerical results, the importance of curing reaction control for UV-NIL process was discussed for deformation characteristics.

• KSBB Journal
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• v.22 no.6
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• pp.433-437
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• 2007

A constant desire has been to fabricate nanopatterns for biochip and the Ultraviolet-nano imprint lithography (UV-NIL) is promising technology especially compared with thermal type in view of cost effectiveness. By using this method, nano-scale to micro-scale structures also called nanopore structures can be fabricated on large scale gold plate at normal conditions such as room temperature or low pressure which is not possible in thermal type lithography. One of the most important methods in fabricating biochips, immobilizing, was processed successfully by using this technology. That means immobilizing proteins only on the nanopore structures based on gold, not on hardened resin by UV is now possible by utilizing this method. So this selective nano-patterning process of protein can be useful method fabricating nanoscale protein chip.