• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2007.06a
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• pp.90-93
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• 2007

밀도가 높고 주기적으로 배열된 실리콘 나노점이 실리콘 기판위에 형성 되었다. 실리콘 나노점을 형성하기 위해 사용된 나노패턴의 지름은 20 나노미터(nm)이고 깊이는 40 nm 이었으며 기공과 기공사이의 거리는 50 nm 였다. 나노미터 크기의 패턴을 형성시키기 위해서 자기조립물질을 사용했으며 폴리스티렌(PS) 바탕에 벌집형태로 평행하게 배열된 실린더 모양의 폴리메틸메타아크릴레이트(PMMA)의 구조를 형성하였다 폴리메틸메타아크릴레이트를 아세트산으로 제거하여 폴리스티렌만 남아있는 나노크기의 마스크를 만들었다. 형성된 나노패턴에 전자빔 기상증착장치를 사용하여 금 박막을 $100\;{\AA}$ 증착하고 리프트오프(lift-off) 방식으로 금 나노점을 만들었다. 형성된 금 나노점을 불소기반의 화학반응성 식각법을 이용하여 식각하고 황산으로 제거하였다. 형성된 실리콘 나노점의 지름은 24 nm 였고 높이는 20 nm 였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.133-133
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• 2004

박막이나 초미세 구조체의 경도 및 탄성계수 측정을 위한 나노 압입실험에서는 Oliver ＆ Pharr가 제안한 하중-변위 측정 나노압입법이 널리 쓰이고 있다 위 실험법에서, 나노경도(nano-hardness; H$_{n}$)는 최대하중을 계산된 접촉면적 (A$_{c}$)으로 나누어 평가하고, 압입자 및 박막의 탄성성질을 포함하는 환산 탄성계수 (reduced modulus ; E$_{r}$)는 하중제거곡선의 초기 기울기인 접촉탄성강성 (S)를 이용하여 계산한다. 그러나, 하중-변위 측정 나노압입법에서는 탄성 및 소성변형만이 고려되고 시간 의존적 변형거동 (time dependent deformation; TDD)은 고려되지 않는다.(중략)

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.3
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• pp.51-58
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• 2018

In this paper, the organic material Poly(methyl methacrylate) PMMA is used with inorganic $Al_2O_3$ to fabricate organic-inorganic multilayer barrier thin films. The organic thin films are developed using a roll-to-roll electrohydrodynamic atomization system, whereas the inorganic are grown using a roll-to-roll low-temperature atmospheric pressure atomic layer deposition system. For the first time, these two technologies are used together to develop organic-inorganic multilayer barrier thin films in atmospheric condition. The films are grown under optimized parameters and classified into three classes based on the layer structures, when the total thickness of the barrier is maintained at ~ 160 nm. All classes of barriers show good morphological, optical and chemical properties. The $Al_2O_3$ films with a low average arithmetic roughness of 1.58 nm conceal the non-uniformity and irregularities in PMMA thin films with a roughness of 5.20 nm. All classes of barriers show a notably good optical transmission of ~ 85 %. The hybrid organic-inorganic barriers show water vapor and oxygen permeation in the range of ${\sim}3.2{\times}10^{-2}g/m^2/day$ and $0.015cc/m^2/day$ at $23^{\circ}C$ and 100% relative humidity. It has been confirmed that it can be mass-produced and used as a low-cost barrier thin film in various printing electronic devices.

• Journal of Sensor Science and Technology
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• v.7 no.2
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• pp.97-102
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• 1998

Organic thin film EL devices using PPV(poly (p-phenylenevinylene)) as emitter were fabricated on various conditions and structures, their electro-optical properties were estimated. Fabricated EL devices had structures of single layer(ITO(indium tin oxide)/PPV/Mg), double layer(ITO/PVK(poly(N-vinylcarbazole))/PPV/Mg and ITO/PPV/Polymer matrix + PBD/Mg) and three layer (ITO/PVK/PPV/PS(polystyrene)+PBD(butyl-2-(4-bipheny])-5-(4-tert-butylphenyl-1,3,4-oxadiazole))/Mg), their electro-optical characteristics were compared with each other. In structure of double layer (ITO/PPV /Polymer matrix + PBD/Mg), the used polymer-matrices were PMMA(poly(methyl methacrylate), PC(polycarbonate), PS and MCH(side chain liquid crystalline homopolymer). When PS as a hole transport layer was used, the luminance characteristics on concentration of PBD was obtained. In results, current-voltage-luminance curves of fabricated devices had characteristics of tunneling effect and the device showed a stable light emitting.

• Applied Chemistry for Engineering
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• v.21 no.2
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• pp.200-204
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• 2010

Surface properties are important for determining the functions and uses of materials. So modification of materials with polymer thin films has emerged as an important method to control the physical and chemical properties of the surface layer. We report a simple and effective method to photochemically attach thin polymeric layers to solid surface without chemical derivatization of the substrate and/or the polymer. The system is based on a photoreactive poly(4-vinylpyridine) (P4VP) thin film which is formed on the $SiO_{2}$ surface via spin coating. This substrate is then covered with another polymer film that is reacted with the benzyl radical moieties by UV irradiation. As a result of photochemical reaction, a thin layer of the later polymer is covalently bound to the surface of P4VP. Unbounded polymer is removed by sonication. The thickness of the attached film is a function of the irradiation time and the molecular weight of the polymer. Spatially defined polymer thin films can be fabricated by way of photolithography.

• Journal of the Korean institute of surface engineering
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• v.50 no.3
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• pp.198-205
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• 2017

Thermal dissipation was investigated for poly methyl methacrylate (PMMA) composite films containing graphite and multi wall carbon nanotube(CNT) powders as filler materials. After mixing PMMA with fillers, solvent, and dispersant, the pastes were prepared by passing through a three roll mill for three times. The prepared pastes were coated $15{\sim}40{\mu}m$ thick on a side of 0.4 mm thick aluminium alloy plate and dried for 30 min at $150^{\circ}C$ in an oven. The content of fillers in dried films was varied as 1, 2, and 5 weight % maintaining the ratio of graphite and CNT as 1:1. Raman spectra from three different samples exhibited D, G and 2D peaks, as commonly observed in graphite and multi wall CNT. Among those peaks, D peak was prominent, which manifested the presence of defects in carbon materials. Thermal emissivity values of three samples were measured as 0.916, 0.934, and 0.930 with increasing filler content, which were the highest ever reported for the similar composite films. The thermal conductivities of three films were measured as 0.461, 0.523, and $0.852W/m{\cdot}K$, respectively. After placing bare Al plate and film coated samples over an opening of a polystyrene box maintained for 1 h at $92^{\circ}C$, the temperatures inside and outside of the box were measured. Outside temperatures were lower by $5.4^{\circ}C$ in the case of film coated plates than the bare one, and inside temperatures of the former were lower by $3.6^{\circ}C$ than the latter. It can be interpreted that the PMMA composite film coated Al plates dissipate heat quicker than the bare Al plate.

• Journal of the Microelectronics and Packaging Society
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• v.13 no.3 s.40
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• pp.13-17
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• 2006

Dense and periodic arrays of holes and tungsten none dots were fabricated on silicon oxide and silicon. The holes were approximately 25 nm wide, 40 nm deep, and 60 nm apart. To obtain nano-size patterns, self-assembling resists were used to produce layer of hexagonally ordered parallel cylinders of polymethylmethacrylate(PMMA) in polystyrene(PS) matrix. The PMMA cylinders were degraded and removed with acetic acid rinse to produce a PS mask for pattern transfer. The silicon oxide was removed by fluorine-based reactive ion etching(RIE). Selectively deposited tungsten nano dots were formed inside nano-sized trench by using a low pressure chemical vapor deposition(LPCVD) method. Tungsten nano dot and trenched silicon sizes were 26 nm and 30 nm, respectively.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.2 s.43
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• pp.17-21
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• 2007

Dense and periodic arrays of holes and Si nano dots were fabricated on silicon substrate. The nanopatterned holes were approximately $15{\sim}40nm$ wide, 40 nm deep and $40{\sim}80\;nm$ apart. To obtain nano-size patterns, self?assembling diblock copolymer were used to produce layer of hexagonaly ordered parallel cylinders of polymethylmethacrylate (PMMA) in polystyrene(PS) matrix. The PMMA cylinders were degraded and removed with acetic acid rinse to produce a PS. $100\;{\AA}-thick$ Au thin film was deposited by using e-beam evaporator. PS template was removed by lift-off process. Arrays of Au nano dots were transferred by using Fluorine-based reactive ion etching(RE). Au nano dots were removed by sulfuric acid. Si nano dots size and height were $30{\sim}70\;nm$ and $10{\sim}20\;nm$ respectively.

• Journal of the Korean Magnetics Society
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• v.17 no.4
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• pp.178-181
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• 2007

Electron beam lithography has been studied as a next-generation lithography technology instead of photo lithography for ULSI semiconductor devices. In this work, we have made a low-energy electron beam lithography system based on the microcolumn and investigated the dependence of the pattern thickness on the energies and dose concentration of the electron beam. We have also demonstrated the potential of low-energy lithography by achieving 100 nm-$SiO_2$ thin film patterning.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.89.1-89.1
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• 2012

실리콘 반도체의 Ultra large scale integration (ULSI) 기술 및 소자의 나노스케일화에 따라 배선 금속 물질로 사용하던 알루미늄 보다 낮은 비저항을 가지면서 금속의 전자이동효과에 잘 견딜 수 있는 차세대 배선 물질로서 구리가 큰 주목을 받고 있다. 하지만 구리의 경우, 높은 확산성을 가지기 때문에 열처리 과정에서 구리 실리사이드가 형성되는 등 소자의 신뢰성 및 성능을 감소시키므로, 이를 방지하기 위한 확산 방지막이 필요하다. IC의 배선에서 사용되는 기존의 확산 방지막은 Ta, TaN, TiN, TiW, TaSiN 등으로, 대부분 금속으로 이루어져 있기 때문에 증착 장비를 이용하여 두께를 조절하는 기술, 박막의 질을 최적화 하는 과정이 필요하며, 증착 과정 중에서 불순물이 함께 증착되거나 실리사이드가 형성되는 등의 단점을 가진다. 구리 기반의 배선 물질에서 문제될 수 있는 또 한가지의 이슈는 소자의 나노스케일화에 따른 배선 선폭의 감소로 인하여 확산 방지막 두께 또한 감소되어야 하는 것으로서, 확산 방지막의 두께가 감소함에 따른 방지막의 균일성 감소, 연속성 등이 큰 문제로 작용할 수 있어 이를 해결하기 위한 새로운 기술 또는 새로운 확산 방지막 물질의 개발이 시급한 실정이다. 본 연구에서는 구리/실리콘 구조에서 금속의 실리콘 박막 내로의 확산 및 실리사이드 형성을 방지하기 위하여 그래핀을 확산 보호막으로서 사용하였다. 그래핀은 화학기상증착법을 이용하여 한 겹에서 수 겹으로 성장되었으며, PMMA 물질을 이용하여 실리콘 기판에 전사되었다. 구리/그래핀/실리콘 구조의 샘플을 500 ~ 800도의 온도 범위에서 열처리 하였고, 구리 실리사이드 형성 여부를 XRD로 분석하였다. 또한 TEM 분석을 통해 구리 실리사이드의 형성 모양을 관측하였다.