• Tribology and Lubricants
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• v.26 no.5
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• pp.297-302
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• 2010

This study is focused on the resin layer formation of UV imprinting process by changing imprinting pressure and period. The mold shape is made for the process of window open over the pattern transfer area and the imprinting period is assigned as the time just before the UV light curing. The residual layer is measured by changing the imprinting period and pressure magnitude, and the measured data of residual layer provides useful information for the design of the process conditions of imprinting processes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.579-580
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• 2013

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.100-103
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• 2007

A microlens array has been required to improve light conversion efficiency in image sensors. A microlens array can be usually fabricated by photoresist reflow, hot-embossing, micro injection molding, and UV-imprinting. Among these processes, a UV-imprinting, which is operated at room temperature with relatively low applied pressure, can be a desirable process to integrate microlens array on image sensors, because this process provides the components with low thermal expansion, enhanced stability, and low birefringence, furthermore, it is more suitable for mass production of high quality microlens array. In this study, to analyze the optical properties of the wafer scale microlens array integrated image sensor, another wafer scale simulated image sensor chip array was designed and fabricated. An aspherical square microlens was designed and integrated on a simulated image sensor chip array using a UV-imprinting process. Finally, the optical performances were measured and analyzed.

• 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.

• Transactions of the Society of Information Storage Systems
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• v.2 no.2
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• pp.91-95
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• 2006

High-density image sensors rave microlens array to improve photosensitivity. It is conventionally fabricated by reflow process. The reflow process has some weak points. UV imprinting process can be proposed as an alternative process to integrate microlens array on photodiodes. In this study, the UV imprionting process to integrate microlens array on image sensor was developed using UV transparent flexible mold and simulated image sensor substrate. The UV transparent flexible mold was fabricated by replicating master pattern using siliconacrylate photopolymer. The releasing property and shape accuacy of siliconacrylate mold was analysed. After UV imprinting process, replication quality and align accuracy was analysed.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.17-21
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• 2005

High-density image sensors have microlens array to improve photosensitivity. It is conventionally fabricated by reflow process. The reflow process has some weak points. UV imprinting process can be proposed as an alternative process to integrate microlens array on photodiodes. In this study, the UV imprionting process to integrate microlens array on image sensor was developed using W transparent flexible mold and simulated image sensor substrate. The UV transparent flexible mold was fabricated by replicating master pattern using siliconacrylate photopolymer. The releasing property and shape accuacy of siliconacrylate mold was analysed. After UV imprinting process, replication quality and align accuracy was analysed.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.9
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• pp.781-786
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• 2015

Recently, studies of 3D printing methods have been working in various applications. For example, the powder base method laminates the prints by using a binding or laser sintering method. However, the draw back of this method is that the post process is time consuming and does not allow for parts to be rapidly manufactured. The binding method requires the post process while the time required for the post process is longer than the manufacturing time. This paper proposes a UV curing binding method with an integrated piezo printing head system. The optimization of an arbitrary waveform generation for the control of a UV curable resin droplet was researched, in addition to developed optimized UV curing processes in multi nozzle ink jet heads.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.237-240
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• 2005

The demand of micro electrical mechanical system (MEMS) bio/chemical sensor is rapidly increasing. To prevent the contamination of sensing area, a filtration system is required in on-chip total analyzing MEMS bio/chemical sensor. A nano-filter was mainly applied in some application detecting submicron feature size bio/chemical products such as bacteria, fungi and so on. We suggested a simple nano-filter fabrication process based on replication process. The mother pattern was fabricated by holographic lithography and reactive ion etching process, and the replication process was carried out using polymer mold and UV-imprinting process. Finally the nano-filter is obtained after removing the replicated part of metal deposited replica. In this study, as a practical example of the suggested process, a nano-dot array was replicated to fabricate nano-filter fur bacteria sensor application.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.873-874
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• 2009

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.21.2-21.2
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• 2009

발광다이오드는 에너지 변환 효율이 높고 친환경적인 장점으로 인하여 차세대 조명용 광원으로 각광받고 있다. 하지만 현재 발광다이오드는 낮은 광추출효율로 인하여 미래의 수요를 충족시킬 수 있을 만큼 충분한 성능의 효율을 나타내지 못하고 있다. 발광다이오드의 낮은 광추출효율은 반도체소재와 외부 공기와의 큰 굴절률 차이로 인하여 발생하는 전반사 현상에 기인한 것으로 이 문제를 해결하기 위하여 발광다이오드 소자의 발광면 및 기판을 텍스처링하는 방법이 중요하게 인식되고 있다. 하지만 현재까지 패턴의 구조에 따른 광추출 특성을 분석한 연구는 미진한 상황이다. 본 연구에서는 임프린팅 및 건식식각 공정을 이용하여 다양한 구조의 나노 및 micron 급 패턴을 발광다이오드의 p-GaN층에 형성하였다. 발광다이오드 기판 위에 하드마스크로 사용하기 위한 SiO2를 50nm 증착한 후 그 위에 UV 임프린팅 공정을 진행하여 폴리머 패턴을 형성시켰다. 임프린팅 공정으로 형성된 폴리머 패턴을 CF4CHF3 플라즈마를 이용하여 SiO2를 건식식각하였고, 이후에 SiCl4와 Ar 플라즈마를 이용한 ICP 식각 공정을 진행하여 p-GaN층을 100nm 식각하였다. 마지막으로 BOE를 이용한 습식식각 공정으로 p-GaN층에 남아있는 SiO2층을 제거하여 p-GaN층에 sub-micron에서 micron급의 홀 패턴을 형성하였다. Photoluminescence(PL) 측정을 통해서 발광다이오드 소자에 형성된 패턴의 구조에 따른 광추출 특성을 분석하였다.