• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1511-1512
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• 2011

마이크로 렌즈를 제작하기 위해 PMMA 몰드를 PMMA 용액을 MEMS 기술을 이용하여 제작한 실리콘 마이크로 홀 어레이에 PMMA 용액을 스핀 코팅하여 제작하였다. PMMA 몰드에 PDMS 용액을 코팅하여 OLED 광추출 향상용 마이크로 렌즈를 제작하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 반도체 재료 센서 박막재료 전자세라믹스
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• pp.125-128
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• 2004

In this paper, a novel processing technique for fabrication of high-temperature MEMS based on polymer-derived SiCN microstructures is described. PDMS molds are fabricated on SU-8 photoresist using standard UV-photolithographic processes. Liquid precursors are injected into the PDMS mold. And then, the resulting solid polymer structures are crosslinked under isostatic pressure, and pyrolyzed to form a ceramic capable of withstanding over $1500^{\circ}C$. These fabricated SiCN structures would be applied for high-temperature applications, such as heat exchanger and combustion chamber.

• 반도체디스플레이기술학회지
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• 제10권4호
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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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.265-266
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• 2013

• 센서학회지
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• 제32권1호
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• pp.44-50
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• 2023

In this study, a polydimethylsiloxane (PDMS)-based drag force-type flowmeter was fabricated using a graphite-carbon nanotube (CNT) composite as a piezoresistive material and evaluated. The device was in the form of a cantilever, which was composed of the soft material, PDMS, and fabricated using a mold manufactured by a three-dimensional printer. The cost-effective graphite was mixed with CNTs to serve as a piezoresistive material. The optimal mixing ratio was investigated, and the piezoresistive material formed using a graphite:PDMS:CNT ratio of 1.5:1:0.01 was adopted, which showed a stable output and a high sensitivity. Various forward and backward air flows in the range of 0-10 m/s were measured using the fabricated flowmeter, and both tensile and compression characteristics were evaluated. The measured results showed a stable output, with the resistance change gradually increasing with the air flow rate. Repeatability characteristics were also tested at a repeated air flow of 10 m/s, and the flowmeter responded to the applied air flow well. Consequently, the fabricated device has a high sensitivity and can be used as a flowmeter.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.216-216
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• 2009

This paper describes a novel processing technique for the fabrication of polymer-derived SiCN (silicone carbonitride) microstructures for extreme microelectromechanical system (MEMS) applications. A polydimethylsiloxane (PDMS) mold was formed on an SU-8 pattern using a standard UV photolithographic process. Next, the liquid precursor, polysilazane, was injected into the PDMS mold to fabricate free-standing SiCN microstructures. Finally, the solid polymer SiCN microstructure was cross-linked using hot isostatic pressure at $400^{\circ}C$ and 205 bar. The optimal pyrolysis and annealing conditions to form a ceramic microstructure capable of withstanding temperatures over $1400^{\circ}C$ were determined. Using the optimal process conditions, the fabricated SiCN ceramic microstructure possessed excellent characteristics includingshear strength (15.2 N), insulation resistance ($2.163{\times}10^{14}\;{\Omega}$, and BDV (1.2 kV, minimum). Since the fabricated ceramic SiCN microstructure has improved electrical and physical characteristics compared to bulk Si wafers, it may be applied to harsh environments and high-power MEMS applications such as heat exchangers and combustion chambers.

• 한국광학회지
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• 제17권4호
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• pp.317-322
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• 2006

본 논문에서는 폴리머 광도파로 열 격자(arrayed waveguide grating: AWG)를 나노임프린트 방법을 이용하여 제안하고 구현하였다. 빔전파방법을 도입하여 소자를 설계하고 해석하였다. 균일한 접착 및 분리 특성을 갖는 임프린트용 PDMS(polydimethylsiloxane) 스탬프(stamp)를 쿼츠 글래스 물질로 만들어진 마스터 몰드를 이용하여 개발하였다. 이 PDMS 스탬프로 폴리머층을 눌러서 소자 패턴을 형성하고 폴리머를 스핀코팅하여 소자를 완성하였다. 이러한 소자는 식각공정 없이 간단한 스핀코팅과 임프린트 공정만으로 만들어지기 때문에 대량 생산에 적합할 것이다. 제작된 폴리머 AWG 소자의 출력 채널 수는 8개, 채널 간격은 0.8nm, 각 채널의 중심파장은 1543.7nm $\sim$ 1548.3nm 였다. 평균적인 채널 누화와 대역폭은 각각 $\sim$10dB와 0.8nm였다.

• KSBB Journal
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• 제18권5호
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• pp.429-433
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• 2003

LAL 측정용 chip을 제작하기 위해서 우선 시료의 부피 감소에 대한 비탁법과 비색법을 비교하였다. 비색법은 낮은 부피에서 높은 감도를 보여 주었으며 시료의 부피와 무관하게 같은 endotoxin의 농도에서는 같은 흡광도를 보인다는 결론을 얻었다. Endotoxin의 농도에 따른 표준곡선을 end point법과 kinetic point법을 비교한 결과 대한약전의 기준에 적합한 kinetic point법이 적합하였다. 이러한 기초 실험결과를 통해 PDMS LOC를 제작하여 LAL 시험을 수행하였다. LOC를 이용하여 더 짧은 시간과 더 작은 시료로 시험이 가능하도록 하였다. 특히 PDMS LOC는 복잡한 channel을 쉽게 만들 수 있을 뿐 아니라 mold를 이용하여 상용화를 위한 대량 생산이 가능하다. 따라서 PDMS를 이용한 LOC의 제작과 실험을 통해 기존의 수작업의 LAL 시험을 LOC를 이용한 다중시료 측정과 자동화의 가능성을 제시하였다.

• 한국정밀공학회지
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• 제21권1호
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• pp.87-93
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• 2004

Recently, with the development of bio-technology the interests in the micro-fluidic devices for analysis in the fields of biology and medical science have been steadily increasing. Although polymer is considered as one of the best materials for micro-fluidic devices. glass or silicon molds fabricated by photo-lithographic technique have been commonly used. However, it is generally perceived that the conventional photolithographic technique has the limitation for fabricating micro-channels for micro-fluidic devices. In this work, the possibility of fabrication of micro-fluidic channels on PDMS by using the mechano-chemical process and the effect of surface states on the fluid flow were investigated. Experimental results revealed that PDMS mold fabricated by the mechano-chemical process could be used effectively to replicate micro-fluidic channels with high reproducibility and dimensional accuracy. It was also found that the fluid flow generation and flow speed were largely affected by the hydrophilicity and the surface roughness of the micro-channel surfaces.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.274.1-274.1
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• 2013

We report the circumferential alignment of human aortic smooth muscle cells (HASMCs) in an orthogonally micropatterned circular microfluidic channel to form an in vivo-like smooth muscle cell layer. To realize a biomimetic smooth muscle cell layer which is aligned perpendicular to the axis of blood vessel, we first fabricated a half-circular polydimethylsiloxane (PDMS) microchannel by soft lithography using a convex PDMS mold. The orthogonally micro wrinkle patterns were generated inside the half-circular microchannel by stretching-releasing operation under UV irradiation. Upon UV treatment with uniaxial 40 % stretch of a PDMS substrate and releasing process, the microwrinkle patterns perpendicular to the axial direction of the circular microchannel were generated, which could guide the circumferential alignment of HASMCs successfully during cultivation. The analysis of orientation angle, shape index, and contractile protein marker expression indicates that the cultured HASMCs revealed the in vivo-like cell phenotype. Finally, we produced circular microchannels by bonding two half-circular microchannels, and cultured the HASMCs circumferentially with high alignment and viability for 5 days. These results are the first demonstration for constructing an in vivo-like 3D smooth muscle cell layer in the circular microfluidic channel which can provide novel bioassay platforms for in-depth study of HASMC biology and vascular function.