• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.91-94
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• 2005

With increasing demands for large-scale micro-optical components in the field of digital display, the establishment of large-scale fabrication technology fur polymeric patterns has become a priority. The starting point of any polymer replication process is the mold, and the mold often has flat surface. However, It is very hard to replicate large-scale micro patterns using the flat mold, because the cost of large-scale flat mold was very high, and some uniformity and releasing problems were often occurred in large scale flat molding process. In this study, a UV roll imprinting system to overcome the financial and fabrication issues of large-scale pattern replication process was designed and constructed. As a practical example of the system, a lenticular lens with radius of curvature of $223{\mu}m$ and pitch of $280{\mu}m$, which was used to provide wide viewing angle in projection TV, was designed and fabricated. The roll stamper was fabricated using direct machining process of aluminum roll base. Finally, the shape accuracy and uniformity of roll imprinted lenticular lens sheet were measured and analyzed.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1115-1117
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• 2009

Resist patterning of all layers in TFT and BM layer in CF were carried out using UV-imprinting Lithography to make a 12.1 inch TFT-LCD panel at the resolution of 1280 ${\times}$ 800 lines (125 ppi). Technical challenges and solutions for resist patterning by UV-imprinting are shown in this article.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1489-1492
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• 2005

Compared to other nano-patterning techniques, Nano imprint Lithography (NIL) has some advantages of high throughput and low process cost. To imprint low temperature and pressure, UV Nano imprint Lithography, which using the monomer based UV curable resin is suggested. Because fabrication of high fidelity pattern on topographical substrate is difficult, bi-layer Nano imprint lithography, which are consist of easily removable under-layer and imprinted pattern, is being used. If residual layer is not remained after imprinting, and under-layer is removed by oxygen RIE etching, we might be able to fabricate the bi-layer pattern for easy lift-off process.

• 반도체디스플레이기술학회지
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• 제12권2호
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• pp.79-84
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• 2013

Nanoimprint lithography (NIL) is the next generation photolithography process in which the photoresist is dispensed onto the substrate in its liquid form and then imprinted and cured into a desired pattern instead of using traditional optical system. There have been considerable attentions on NIL due to its potential abilities that enable cost-effective and high-throughput nanofabrication to the display device and semiconductor industry. 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, with the rolling type imprinting process, a mold, placed upon the $2^{nd}$ generation TFT-LCD glass sized substrate($370{\times}470mm^2$), is rolled by a rubber roller to achieve a uniform residual layer. The prediction of residual layer thickness of the photoresist by rolling of the rubber roller is crucial to design the rolling type imprinting process, determine the rubber roller operation conditions-mpressing force & feeding speed, operate smoothly the following etching process, and so forth. First, using the elasticity theory of contact problem and the empirical equation of rubber hardness, the contact length between rubber roller and mold is calculated with consideration of the shape and hardness of rubber roller and the pressing force to rubber roller. Next, using the squeeze flow theory to photoresist flow, the residual layer thickness of the photoresist is calculated with information of the viscosity and initial layer thickness of photoresist, the shape of mold pattern, feeding speed of rubber roller, and the contact length between rubber roller and mold previously calculated. Last, the effects of rubber roller operation conditions, impressing force & feeding speed, on the residual layer thickness are analyzed with consideration of the shape and hardness of rubber roller.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.104-107
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• 2007

An aspheric microlens array to improve the properties of multi optical probes was designed and fabricated. To generate multi optical probes with good qualities, a microlens array with the minimum spherical aberration was designed by ray tracing. Using the reflow process, a master pattern of aspheric microlens array was made and finally with the ultraviolet-imprinting (UV-imprinting) method, the aspheric microlens array was replicated. The reflow condition was optimized to realize the master pattern of the microlens array with the designed aspheric shape. The intensity distribution of the optical probes at the focal plane showed a diffraction-limited shape.

• Journal of Information Display
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• 제11권2호
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• pp.49-51
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• 2010

Nanoimprint lithography (NIL) using ultraviolet (UV) rays is a technique in which unconventional lithographic patterns are formed on a substrate by curing a suitable liquid resist in contact with a transparent patterned mold, then releasing the freshly patterned material. Here, various solutions are introduced to achieve sufficient overlay accuracy and to overcome the technical challenges in resist patterning via UV imprinting. Moreover, resist patterning of all the layers in TFT and of the BM layer in CF was carried out using UV imprinting lithography to come up with a 12.1-inch TFT-LCD panel with a resolution of $1280{\times}800$ lines (125 ppi).

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.196-198
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• 2003

Classical lithography in semiconductor employs stepper technologies. Limits of this technology are clearly seen at structures below 100nm. Nano-imprinting lithography is a new method for generating patterns in submicron range at reasonable cost. In order to manufacture nano-imprinting lithography(NIL) equipment, several NIL manufacturers have been developing key technologies for realization of nano-imprinting process, recently. In this paper, we've been describe state-of-the-art and technology trends for nano-imprinting lithography equipments.

• 폴리머
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• 제36권4호
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• pp.536-541
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• 2012

실리카 입자가 첨가된 광경화성 임프린트용 복합체를 제조하여 실리카 양에 따른 경화 특성과 전사된 수 백 나노미터 크기의 임프린트 패턴 형성에 관한 결함을 조사하였다. 상온에서 UV 경화한 임프린트 레진은 실리카 양이 증가할수록 탄성률이 커지고 수축률이 줄어드는 것을 알 수 있었다. 그러나 실리카 입자의 양이 7 wt% 이상인 경우 전사된 나노기둥끼리 서로 달라붙는 결함을 보이는데, 이는 실리카 입자가 광반응을 방해하여 임프린트 레진의 경화가 불완전하게 되면서 광경화된 레진의 점성이 증가했기 때문이다. 임프린트 레진에 실리카 입자를 충전제로 사용하면 경화 후 나노 패턴의 강도를 증가하여 형태를 유지하는데 도움이 되지만, 실리카 양이 7 wt% 이상이 되면 오히려 광반응 전환율이 떨어져 임프린트 공정에 의한 나노 패턴의 전사가 어려운 것을 알 수 있다.

• 반도체디스플레이기술학회지
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• 제9권2호
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• pp.91-96
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• 2010

In recent years 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 consider the roll-to-plate type imprinting process. In the process a glass mold, which is placed upon the 2nd generation TFT-LCD glass sized substrate(370${\yen}$470 mm), is rolled by a rubber roller to achieve a uniform residual layer. The pressure distribution on the glass mold by rolling of the rubber roller is crucial information to analyze mold deformation, transferred pattern quality, uniformity of residual layer and so forth. In this paper the quantitative pressure distribution induced by rolling of the rubber roller was calculated with finite element analysis under the assumption of Neo-Hookean hyperelastic constitutive relation. Additionally the numerical results were verified by the experiments.

• 소성∙가공
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• 제14권5호
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• pp.473-476
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• 2005

The demand of on-chip total analyzing system with MEMS (micro electro mechanical system) bio/chemical sensor is rapidly increasing. In on-chip total analyzing system, to detect the bio/chemical products with submicron feature size, a filtration system with nano-filter is required. One of the conventional methods to fabricate nano-filter is to use direct patterning or RIE (reactive ion etching). However, those procedures are very costly and are not suitable fur mass production. In this study, we suggested new fabrication method for a nano-filter based on replication process, which is simple and low cost process. After the Si master was fabricated by laser interference lithography and reactive ion etching process, the polymeric mold was replicated by UV-imprint process. Metallic nano-filter was fabricated after removing the polymeric part of metal deposited polymeric mold. Finally, our fabrication method was applied to metallic nano-filter with $1{\mu}m$ pitch size and $0.4{\mu}m$ hole size for bacteria sensor application.