• Journal of the Korean institute of surface engineering
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• v.52 no.2
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• pp.84-89
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• 2019

We fabricated durable anti-reflective(AR) layer with silica globular coating on polymer by two steps. Firstly, nano-protrusions of polymer were formed by plasma etching known as R.I.E(reactive ion etching) process. Secondly, silica globular coating was deposited on polymer nano-protrusions for mechanically protective and optically enhancing AR layers by RF magnetron sputter. And then durable antireflective polymers were synthesized adjusting plasma power and time, working pressures of RIE and RF sputtering processes. Consequently, we acquired the average transmission (94.10%) in the visible spectral range 400-800 nm and the durability of AR layer was verified to sustain its transmission until 5,000 numbers by rubber test at a load of 500 gf.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.32-32
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• 2011

Plasma etching is used in microelectronic processing for patterning of micro- and nano-scale devices. Commonly, optical emission spectroscopy (OES) is widely used for real-time endpoint detection for plasma etching. However, if the viewport for optical-emission monitoring becomes blurred by polymer film due to prolonged use of the etching system, optical-emission monitoring becomes impossible. In addition, when the exposed area ratio on the wafer is small, changes in the optical emission are so slight that it is almost impossible to detect the endpoint of etching. For this reason, as a simple method of detecting variations in plasma without contamination of the reaction chamber at low cost, a method of measuring plasma impedance is being examined. The object in this research is to investigate the suitability of using plasma impedance monitoring (PIM) with statistical approach for real-time endpoint detection of $SiO_2$ etching. The endpoint was determined by impedance signal variation from I-V monitor (VI probe). However, the signal variation at the endpoint is too weak to determine endpoint when $SiO_2$ film on Si wafer is etched by fluorocarbon plasma on inductive coupled plasma (ICP) etcher. Therefore, modified principal component analysis (mPCA) is applied to them for increasing sensitivity. For verifying this method, detected endpoint from impedance analysis is compared with optical emission spectroscopy (OES). From impedance data, we tried to analyze physical properties of plasma, and real-time endpoint detection can be achieved.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.212-212
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• 1999

Ar-O2 분위기의 Plasma 표면 처리된 OPP 의 polymer 위에 약 400$\AA$ 정도로 sputter 코팅된 Al의 부착력에 관하여 연구를 하였다. 금속과 polymer와 같이 성질이 서로 다른 물질이 서로 결합할 때 접착력은 제품의 성능과 신뢰도를 결정하는데 매우 중요한 인자이다. 최근 고분자재료의 표면을 플라즈마 처리 (plasma surface treatment)에 의해 고분자와 금속도포(coating) 층간의 접착력향상에 따라, 증착필름 및 인쇄용 필름 등의 기능도 향상시킬 수 있다. 저온 plasma를 이용한 표면처리는 plastic 재료가 가지고 있는 기본적인 특성을 저해하지 않고, 그 표면 층만을 개량하는 plasma 또는 sputter etching 갚은 electrical discharge 방법은 진공 증착 방식에서 많이 사용되고 있다. 7$\mu\textrm{m}$의 두께 OPP polymer를 10m/min의 속도로 OPP의 표면을 연속 plasma pretreatment를 하였다. 5$\times$10-2torr에서, PEM(Plasma Emission Monitor)를 이용하여 plasma intensity에 따른 Ar/O2비를 변화시키면서 test를 하였다. AFM과 XPS를 이용하여 OPP의 표면분석을 하였다. 이 plasma처리는 기존의 D.C plasma 처리 방식과는 달리 Midium frequency AC voltage hollow cathod 방식으로 plasma를 발생된 high energy plasma 분위기를 만들 수 있다. 이러한 방식은 -cycle일 때 plasma로부터 발생된 전자가 polymer 표면을 bombard 하게 되고, +cycle 일 때 polymer 표면이 cathod 가 되어 active ion에 의해 sputtering 이 된다. 이때 plasma 처리기의 polymer 기판 후면에 magnet를 설치하여 높은 ionization을 발생시켜 처리 효과를 한층 높여 주었다. 이 plasma 처리는 표면 청정화, 표면 etching 이 동시에 행하는 것과 함께 장시간 처리에 의해 표면에서는 미세한 과, C=C기, -C-O-의 극성기의 도입에 의한 표면 개량이 된다는 것을 관찰할 수 있다. OPP polymer 표면을 Ar 100%로 plasma 처리한 경우 C-O, C=O 등의 carbonyl가 발생됨을 알 수 있었다. C-O, C=O 등의 carbynyl polor group이 도입됨에 따라 sputter된 Al의 접착력이 향상됨을 알 수 있으며, TEM 관찰 결과 grain size도 상당히 작아짐을 알 수 있었다.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.1
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• pp.152-158
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• 1995

Eteching characteristics of the Indium Tin Oxide (ITO), which is transparent conductor, was investigated with CH4/H2 and Ar as etching gases for the Reactive Ion Etching (RIE). With CH4/H2 for the etching gas, the highly selective etching characteristics for the ITO on GaAs was obtained. It was examined that the dominant etching parameter for the selective etchning of ITO on GaAs structure was the chamber pressure. But, the etching selectivity for ITO on InP was poor eventhough we tried systematic etching. RIE etching conditins using CH4/H2 gas was limited due to the formation of polymer on the substrates. In the case of Ar gas for the reactive gas, the selectivity of ITO on BaTiO3 was above 10. The etch rete of ITO was more sensitive to the etching parameters than that of BaTiO3, which was almost constant with different etching parameters.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.153-153
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• 2012

Endpoint detection with plasma impedance monitoring and self-plasma optical emission spectroscopy is demonstrated for dielectric layers etching processes. For in-situ detecting endpoint, optical-emission spectroscopy (OES) is used for in-situ endpoint detection for plasma etching. However, the sensitivity of OES is decreased if polymer is deposited on viewport or the proportion of exposed area on the wafer is too small. To overcome these problems, the endpoint was determined by impedance signal variation from I-V monitoring (VI probe) and self-plasma optical emission spectroscopy. In addition, modified principal component analysis was applied to enhance sensitivity for small area etching. As a result, the sensitivity of this method is increased about twice better than that of OES. From plasma impedance monitoring and self-plasma optical emission spectroscopy, properties of plasma and chamber are analyzed, and real-time endpoint detection is achieved.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.2
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• pp.59-64
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• 2014

Transfer is the critical issue of producing high-quality and scalable graphene electronic devices. However, conventional transfer processes require the removal of an underlying metal layer by wet etching process, which induces significant economic and environmental problems. We propose the etching-free mechanical releasing of graphene using polymer adhesives. A fracture mechanics approach was introduced to understand the releasing mechanism and ensure highyield process. It is shown that the thickness of adhesive and target substrate affect the transferability of graphene. Based on experimental and fracture mechanics simulation results, we further observed that compliant adhesives can reduce the adhesive stress during the transfer, which also enhances the success probability of graphene transfer.

• Applied Microscopy
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• v.29 no.4
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• pp.405-415
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• 1999

In general, transmission electron microscopy (TEM) is usually used in the investigation of polymer microstructure. Microtoming, solution casting, staining and carbon replica method are frequently introduced to the study of the polymer morphology with TEM, however the sample preparation procedure of those techniques is very difficult, and it takes a long time. The purpose of this study is to develop a new sample preparation technique which is suitable for the investigation of the various shapes and species of polyolefin microstructure by scanning electron microscopy (SEM). By modifying the conventional chemical etching method, we developed a new chemical etching technique and sample preparation procedure that are suitable for SEM study of polymer microstructure. In this study the permanganate etching method is introduced and the optimum etching condition are determined by simply adjusting the etchant formulation, concentration and etching time. This technique has shown good reproducibility and it's morphological results agree well with other works on various types of microstructures such as spherulite characterization of isotatic polypropylene $(\alpha/\beta)$, polyethylene and poly-propylene copolymer characterization, and the study of lamellar growth pattern of unsheared or oriented materials. This technique has also been applied to the industrial fields for characterization of the polyolefin film, automobile products and the others.

• Transactions of the Society of Information Storage Systems
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• v.1 no.2
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• pp.192-196
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• 2005

In this paper, we investigated the possibility of replicating patterned media by nano-injection molding process with a metallic nano-stamper. The original nano-master was fabricated by E-beam lithography and ICP etching process. The metallic nano-stamper was fabricated using a nanoimprint lithography and nano-electroforming process. The nano-patterned substrate was replicated using a nano-injection molding process without additional etching process. In nano-injection molding process, since the solidified layer, generated during the polymer filling, deteriorates transcribability of nano patterns by preventing the polymer melt from filling the nano cavities, an injection-mold system was constructed to actively control the stamper surface temperature using MEMS heater and sensors. The replicated polymeric patterns using nano-injection molding process were as small as 50 nm in diameter, 150 nm in pitch, and 50 nm in depth. The replicated polymeric patterns can be applied to high density patterned media.

• Proceedings of the Materials Research Society of Korea Conference
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• 1997.05a
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• pp.27-27
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• 1997

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1999.10a
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• pp.84-84
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• 1999