• Journal of the Korean Vacuum Society
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• v.13 no.1
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• pp.39-45
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• 2004

Ultraviolet-nanoimprint lithography (UV-NIL) is a promising method for cost-effectively defining nanoscale structures at room temperature and low pressure. A 5${\times}$5${\times}$0.09 in. quartz stamp is fabricated using the etch process in which a Cr film was employed as a hard mask for transferring nanostructures onto the quartz plate. FAS(Fluoroalkanesilane) is used as a material for anti-adhesion surface treatment on the stamp and a thin organic film to improve adhesion on a wafer is formed by spin-coating. The low viscosity resin droplets with a nanometer scale volume are dispensed on the whole area of the coated wafer. The UV-NIL experiments have been performed using the EVG620-NIL. 370 nm - 1 m features on the stamp have been transferred to the thin resin layer on the wafer using the multi-dispensing method and UV-NIL process. We have measured the imprinted patterns and residual layer using SEM and AFM to evaluate the potential of the process.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.81.1-81.1
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• 2012

나노임프린트 리소그라피(Nano-Imprint Lithography, NIL) 기술은 기판위의 resin을 나노구조물이 각인된 스탬프로 눌러서 나노구조물을 형성하는 기술로, 경제적이고 효과적으로 나노구조물을 제작할 수 있는 기술이다. 그중에서도 UV 기반의 나노임프린트(UV-NIL) 기술은 resin을 투명한 스탬프로 누른뒤 UV로 경화시켜 나노구조물을 형성하는 기술로써 고온, 고압($140{\sim}180^{\circ}C$, 10~30bar)이 필요한 가열식 나노임프린트 기술에 비해 상온, 상압($20^{\circ}C$, 1bar)에서도 구조물 형성이 가능하여 다층구조 형성에 적합하다. 연속적인 임프린팅 공정에 의해 resin이 quarz 스탬프에 잔류하여 패터닝에 결함을 유발하게 되므로 오염물을 제거하기 위한 세정공정이 필요하다. 하지만 UV에 의해 경화된 resin은 cross-linking을 형성하여 화학적인 내성이 증가하게 되므로 제거하기가 어렵다. 현재는 resin 제거를 위한 세정공정으로 SPM($H_2SO_4/H_2O_2$) 세정이 사용되고 있는데 세정시간이 길고 세정 후에 입자 또는 황 잔유물이 남으며 많은 유해용액 사용의 문제점이 있어 효과적으로 resin을 제거할 세정공정이 필요한 상황이다. 본 연구에서는 친환경적인 UV 세정 및 오존수 세정공정을 적용하여 경화된 resin을 제거하는 연구를 진행하였다. 실험샘플은 약 100nm 두께의 resin을 증착한 $1.5cm{\times}1.5cm$ $SiO_2$ 쿠폰 wafer를 사용하였으며, UV 및 오존수의 처리시간을 달리하여 resin 제거효율을 평가하였다. ATR-FTIR 장비를 사용하여 시간에 따른 resin의 두께를 측정한 결과, UV 세정으로 100nm 높이의 resin중에 80nm의 bulk resin이 단시간에 제거가 되었고 나머지 20nm의 resin thin film은 오존수 세정으로 쉽게 제거되는 것을 확인 하였다. 또한 표면에 남은 resin residue와 particle을 제거하기 위해서 SC-1 세정을 진행하였고 contact angle과 optical microscope 장비를 사용하여 resin이 모두 제거된 것을 확인하였다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.6
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• pp.7-14
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• 2011

This paper is related to a roll-type micro-contact printing process. The proper parameters such as coating velocity, inking velocity, printing velocity and printing pressure as well as Ag contents of Ag ink were extracted to perform the fine patterning of Ag electrodes. Additionally we developed a process for PDMS with high uniform thickness. Finally, we obtained the Ag fine electrodes on $4.5cm\;{\times}\;4.5cm$ plastic substrate with the line width of 10 um, thickness less than 300 nm, surface roughness less than 40 nm, and the specific resistance of $2.08\;{\times}\;10^{-5}{\Omega}{\cdot}cm$.

• Polymer(Korea)
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• v.37 no.1
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• pp.1-4
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• 2013

We proposed a new process to fabricate a high-aspect-ratio microhair having surface wrinkles using the contact-and-tension of a microstamp. Through this work, we observed that regular surface wrinkles were generated on the hair with a diameter of around $20{\mu}m$ due to the uni-directional compressive stress during the photocuring process by ultraviolet light. To do this, we conducted an experimental system setup for contact-and-tension process. From the preliminary test results, we believed that the proposed method can be applied to make a long polymer hair having surface wrinkles for special applications to biomimetics, and some research fields related on surface area such as heat transfer and catalyst enhancement.

• Journal of KIISE:Databases
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• v.34 no.3
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• pp.217-231
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• 2007

Frequent disconnection is connected directly to client's cache consistency problem in Mobile Computing environment. For solving cache consistency problem, research about Invalidation Report is studied. But, existent invalidation report structure comes with increase of size of invalidation report structure and decline of cache efficiency if quantity of data become much, or quantity of updated data increases. Also, while existent method confirms whole cache, invalidation report doesn't support selective listening. This paper proposes TTCI(Timestamp Tree-based Cache Invalidation scheme) as invalidation report structure that solve problem of these existing schemes and improve efficiency. We can make TTCI using timestamp of updated data, composing timestamp tree and list ID of data in updated order. If we utilize this, each client can confirm correct information in point that become own disconnecting and increase cache utilization ratio. Also, we can pare down client's resources consumption by selective listening using tree structure. We experimented in comparison with DRCI(Dual-Report Cache Invalidation) that is existent techniques to verify such efficiency of TTCI scheme.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.309-310
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.89-90
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.635-636
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.703-704
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.523-524
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• 2010