• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.99-100
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• 2007

Transferring patterns from mold to PDMS stamp is very useful technology in micro-fabrication, complex and three-dimensional structures. First experimentation, mold's patterns wens transferred to PDMS stamp. Comparing with PDMS stamp and Mold, patterns were transferred about 97.9%. Second experimentation, PDMS stamps were made several times by only one mold, scale and distance of transferred patterns were uniform about 89.3%. We proved that transferring patterns from mold to PDMS stamp is accurate. The uniformity of stamps is the same after mold was used several times. Transferring patterns from mold to PDMS stamp has uniformity and accuracy, it will be useful technology.

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 2006년도 추계학술발표대회 논문집
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• pp.96-102
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• 2006

In this study, manufacturing of polymer master, PDMS(poly dimethylsiloxane) transfer mold, and mold insert was investigated for laser LIGA(LIthography Calvanoformung Abformtechnik). Initially, ablation by excimer laser radiation was used successfully to make 3-D microstructure of PET. After then, the PDMS transfer mold was replicated using ablated PET. Finally, epoxy resin tooling on replicated PDMS transfer mold was executed for making mold insert. From these facts we can conclude that excimer laser ablation of polymer and fabricaiton of PDMS transfer mold are reasonable tools to substitute for X-ray lithography of LIGA process in microstructuring.

• 한국산학기술학회논문지
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• 제5권3호
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• pp.223-226
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• 2004

나노 패턴을 갖는 미세 구조물을 낮은 비용으로 생산하기 위해서는 플라스틱 재료를 이용하는 것이 필수적이고, 대량생산이 가능한 가공방법으로 사출성형 공정기술이 유망하다. 본 연구에서는 e-beam 리소그라피로 제작된 석영원판 내의 100-500nm크기의 선과 점 형상을 간단한 thermal embossing 공정을 이용하여 액상 PDMS를 고형화 시킨 후에 원판과 분리시켜 PDMS 몰드를 제작하였다. 실험결과, 원판에 있는 나노 크기의 다양한 패턴들은 PDMS 몰드에 균일하게 전사되었고, 이 몰드는 사출성형용 스탬퍼 제작에 유용하게 이용될 수 있을 것으로 사료된다.

• 센서학회지
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• 제22권5호
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• pp.352-356
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• 2013

We developed a novel fabrication method of polydimethylsioxane (PDMS) lens, which can easily control the shapes of the lens using soft lithography with common photolithography and water droplet molding. A mold for PDMS lens was prepared by patterning of hydrophobic photoresist on the hydrophilic substrate and dispensing small water droplets onto the predefined hydrophilic patterns. The size of patterns determined the dimension of the lens and the dispensed volume of the water droplet decided the radius of curvature of the PDMS lens independently. The water droplet with photoresist pattern played a robustly fixed mold for lens due to difference in wettability. The radius of curvature could be calculated theoretically because the water droplets could approximate spherical cap on the substrate. Finally, concave and convex PDMS lenses which could reduce or magnify optically were fabricated by curing of PDMS on the prepared mold. The measured radii of the fabricated PDMS lenses were well matched with the estimated values. We believe that our simple and efficient fabrication method can be adopted to PDMS microlens and extended to micro optical device, lab on a chip, and sensor technology.

• 대한기계학회논문집A
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• 제31권12호
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• pp.1194-1199
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• 2007

A unique fabrication method for a copper micromesh is proposed and demonstrated. A PDMS mold was fabricated using a microcasting process and then used as a flexible mold in copper electroplating. The fabricated copper micromesh was well formed and connected without any cracks within the entire mold area. The experimental results verified that the fabricated features of the copper micromesh accurately followed the shape of the microstructures of the PDMS mold. This unique fabrication method provides an easy yet precise means of producing three-dimensional metal microstructures.

• 한국정밀공학회지
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• 제23권8호
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• pp.178-184
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• 2006

Hot embossing is to fabricate desired pattern on the polymer substrate by pressing the patterned mold against the substrate which is heated above the glass transition temperature, and it is a high throughput fabrication method for bio chip, optical microstructure, etc. due to the simultaneous large area patterning. However, the bad pattern fidelity in large area patterning is one of the obstacles to applying the hot embossing technology for mass production. In the present study, PDMS pad was used as a cushion on the backside of the micro-patterned 4 inch Si mold to improve the pattern fidelity over the 4 inch PMMA sheet by increasing the conformal contact between the Si mold and the PMMA sheet. The pattern replicability improvement over 4 inch wafer scale was evaluated by comparing the replicated pattern height and depth for PDMS-cushioned Si mold against the rigid Si mold without PDMS cushion.

• 한국정밀공학회지
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• 제24권4호
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• pp.153-158
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• 2007

Recently nano imprint lithography to fabricate photonic crystal on polymer is preferred because of its simplicity and short process time and ease of precise manufacturing. But, the technique requires the precise mold as an imprinting tool for good replication. These molds are made of the silicon, nickel and quartz. But this is not desirable due to complex fabrication process, high cost. So, we describe a simple, precise and low cost method of fabricating PDMS stamp to make the photonic crystals. In order to fabricate the PDMS mold, we make the original pattern with designed hole array by finding the optimal electron beam writing condition. And then, we have tried to fabricate PDMS mold by the replica molding with ultrasonic vibration and pressure system. We have used the cleaning process to solve the detaching problem on the interface. Using these methods, we acquired the PDMS mold for photonic crystals with characteristics of a good replication. And the accuracy of replication shows below 1% in 440nm at diameter and in 610nm at lattice constant by dimensional analysis by SEM and AFM.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.599-600
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• 2008

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.373-374
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• 2010

• 센서학회지
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• 제15권1호
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• pp.53-57
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• 2006

This paper describes a novel processing technique for fabrication of polymer-derived SiCN (silicone carbonitride) microstructures for super-temperature MEMS applications. PDMS (polydimethylsiloxane) mold is fabricated on SU-8 photoresist using standard UV photolithographic process. Liquid precursor is injected into the PDMS mold. Finally, solid polymer structure is cross-linked using HIP (hot isostatic pressure) at $400^{\circ}C$, 205 bar. Optimum pyrolysis and annealing conditions are determined to form a ceramic microstructure capable of withstanding over $1400^{\circ}C$. The fabricated SiCN ceramic microstructure has excellent characteristics, such as shear strength (15.2 N), insulation resistance ($2.163{\times}10^{14}{\Omega}$) and BDV (min. 1.2 kV) under optimum process condition. These fabricated SiCN ceramic microstructures have greater electric and physical characteristics than bulk Si wafer. The fabricated SiCN microstructures would be applied for supertemperature MEMS applications such as heat exchanger and combustion chamber.