• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1119-1122
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• 2005

A selective deposition of Co thin films for thin film transistor gate electrode has been carried out by the growth with combination of micro-contact printing and metal organic chemical vapor deposition (MOCVD). This results in the elimination of optical lithography process. MOCVD has been employed to selectively deposit Co films on preformed OTS gate pattern by using micro-contact printing (${\mu}CP$). A hydrogenated amorphous silicon TFT with a Co gate selectively formed on SAMs patterned structure exhibited a subthreshold slope of 0.88V/dec, and mobility of $0.35cm^2/V-s$, on/off current ratio of $10^6$, and a threshold voltage of 2.5V, and thus demonstrating the successful application of the novel bottom-up approach into the fabrication of a-Si:H TFTs.

• Journal of Information Display
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• 제7권2호
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• pp.12-15
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• 2006

We propose a patterning method of liquid crystal (LC) alignment layer for producing multi-domain LC structures. By controlling thermal conditions during micro-contact printing procedures and facilitating wetting properties of patterning materials, patterned LC orientation can be easily obtained on a bare ITO surface or other polymer films. The newly proposed patterning method is expected to be a very useful tool for fabricating multi-domain LC structures to enhance or design electro-optic properties of LC-based devices.

• 한국전기전자재료학회논문지
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• 제29권9호
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• pp.571-575
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• 2016

Recently, there has been much focus on the controlled alignment and patterning process of nanowires for nanoelectronic devices. A simple and effective method for patterning of highly aligned nanowires using a microcontact printing technique is demonstrated. In this method, nanowires are first directionally aligned by contact printing, following which line and space micropatterns of nanowire arrays are accomplished by microcontact printing with a micro patterned NOA mold.

• 한국전기전자재료학회논문지
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• 제26권11호
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• pp.841-845
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• 2013

We give a textured front on silicon wafer for high-efficiency solar cells by using micro contact printing method which uses PDMS (polydimethylsiloxane) silicon rubber as a stamp and SAM (self assembled monolayer)s as an ink. A random pyramidal texturing have been widely used for a front-surface texturing in low cost manufacturing line although the cell with random pyramids on front surface shows relatively low efficiency than the cell with inverted pyramids patterned by normal optical lithography. In the past two decades, the micro contact printing has been intensively studied in nano technology field for high resolution patterns on silicon wafer. However, this promising printing technique has surprisingly never applied so far to silicon based solar cell industry despite their simplicity of process and attractive aspects in terms of cost competitiveness. We employ a MHA (16-mercaptohexadecanoic acid) as an ink for Au deposited $SiO_2/Si$ substrate. The $SiO_2$ pattern which is same as the pattern printed by SAM ink on Au surface and later acts as a hard resist for anisotropic silicon etching was made by HF solution, and then inverted pyramidal pattern is formed after anisotropic wet etching. We compare three textured surface with different morphology (random texture, random pyramids and inverted pyramids) and then different geometry of inverted pyramid arrays in terms of reflectivity.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.235-240
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• 2009

Crystlline silicon solar cells markets are increasing at rapid pace. now, crystlline silicon solar cells markets screen-printing solar cell is occupying. screen-printing solar cells manufacturing process are very quick, there is a strong point which is a low cost. but silicon and metal contact, uses Ag & Al pates. because of, high contact resistance, high series resistance and sintering inside process the electric conductivity decreases with 1/3. and In pastes ingredients uses Ag where $80{\sim}90%$ is metal of high cost. because of low cost solar cells descriptions is difficult. therefore BCSC(Buried Contact Solar Cell) is developed. and uses light-induced plating, ln-line galvanization developed equipments. Ni/Cu matel contact solar cells researches. in Germany Fraunhofer ISE. In order to manufacture high-efficiency solar cells, metal selections are important. metal materials get in metal resistance does small, to be electric conductivity does highly. efficiency must raise an increase with rise of the curve factor where the contact resistance of the silicon substrate and is caused by few with decrement of series resistance. Ni metal materials the price is cheap, Ti comes similar resistance. Cu and Ag has the electric conductivity which is similar. and Cu price is cheap. In this paper, Ni/Cu/Ag metal contact cell with screen printing manufactured, silicon metal contact comparison and analysis.

• Current Photovoltaic Research
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• 제2권4호
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• pp.173-176
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• 2014

We have investigated the seed layer formation of front side contact using the inkjet printing process. Conductive silver ink was printed on textured Si wafers with 80 nm thick $SiN_x$ anti reflection coating (ARC) layers and thickened by light induced plating (LIP). The inkjet printable sliver inks were specifically formulated for inkjet printing on these substrates. Also, a novel method to prepare nano-sized glass frits by the sol-gel process with particle sizes around 5 nm is presented. Furthermore, dispersion stability of the formulated ink was measured using a Turbiscan. By implementing these glass frits, it was found that a continuous and uniform seed layer with a line width of $40{\mu}m$ could be formed by a inkjet printing process. We also investigated the contact resistance between the front contact and emitter using the transfer length model (TLM). On an emitter with the sheet resistance of $60{\Omega}/sq$, a specific contact resistance (${\rho}_c$) below $10m{\Omega}{\cdot}cm^2$ could be achieved at a peak firing temperature around $700^{\circ}C$. In addition, the correlation between the contact resistance and interface microstructures were studied using scanning electron microscopy (SEM). We found that the added glass particles act as a very effective fire through agent, and Ag crystallites are formed along the interface glass layer.

• 대한전자공학회논문지SD
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• 제47권2호
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• pp.7-14
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• 2010

본 논문에서는 금속 전극을 미세접촉인쇄방식으로 Ag ink를 이용하여 제작하는데 있어서 접착속도, 분리속도, 접촉시간의 세 가지의 동역학적 파라미터가 잉크 전이율에 미치는 영향을 분석하여 최적의 공정조건을 도출하였다. 잉킹공정에서는 접촉속도는 1 mm/s 이하, 접촉 후 유지시간은 짧게 하며, 분리속도는 1000 mm/s로 빠르게 해야 잉크의 전이율이 98%이상 높았다. 프린팅 공정에서는 반대로 접촉속도는 100mm/s 이상의 빠르게, 접촉 후 유지시간은 30초 이상, 분리속도는 1mm/s 이하로 느리게 할 때 최고의 인쇄특성을 보였다. 이를 이용해 전체 $5cm{\times}5cm$ 면적에 최소 선폭 $30{\mu}m$, 두께는 300~500nm, 50nm이하의 약 $15{\sim}16{\mu\Omega\cdot}cm$ 비저항을 가지는 전극을 인쇄하였다.

• 마이크로전자및패키징학회지
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• 제17권1호
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• pp.47-53
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• 2010

본 연구에서는 솔더 페이스트를 이용한 프린팅 공정의 해석에 대해 연구를 수행하였다. 스텐실 프린팅 공정의 설계에서 중요한 인자는 프린팅 조건, 스텐실 설계, 그리고 솔더 페이스트의 물성 등이다. 본 연구에서는 이 인자들 중에서, 솔더 페이스트의 점도와 표면장력, 그리고 솔더 페이스트와 스텐실 사이의 접촉각이 프린팅 공정의 성능에 미치는 영향을 해석을 통해 파악하였다. 실제 해석에 앞서 압력에 의해서 솔더 페이스트가 스텐실에 채워지는 단순화된 형상과 조건으로 해석을 수행하였다. 해석은 마이크로 유동의 해석에 많이 이용이 되고 있는 상용 소프트웨어인 콤솔(COMSOL)을 이용하였고 축대칭으로 해석하였다. 해석 결과, 솔더 페이스트의 점도는 충진률에 큰 영향을 줌을 알 수 있었고 표면장력과 접촉각은 충진되는 형상에 영향을 줌을 알 수 있었다.

• Journal of Electrical Engineering and Technology
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• 제7권1호
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• pp.91-96
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• 2012

We introduce an understanding of silver (Ag) inkjet overlap-printing characteristics from the viewpoints of cohesion between ink droplets and adhesion between an ink droplet and a surface. The printing characteristics were closely monitored by changing the surface energy to elucidate the effect of adhesion and cohesion on printing instability, such as droplet merging and line bulging. The surface energy of the substrate was changed through the hydrophilization of a hydrophobic fluorocarbon-coated surface. The surface energy and ink wettability of the prepared surfaces were characterized using sessile drop contact angle analysis, and printing instability was observed using an optical microscope after drop-on-demand inkjet printing with a 50% overlap in diameter of deposited singlet patterns. We found that the surface energy is not an appropriate indicator based on the experimental results of Ag ink printing on a hydrofluoric-treated silicon surface. The analytical approach using adhesion and cohesion was helpful in understanding the instability of the inkjet overlap-printing, as adhesion and cohesion represent the direct interfacial relationship between the Ag inks used and the substrate.

• Korean Chemical Engineering Research
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• 제48권3호
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• pp.397-400
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• 2010

스크린 프린팅에서의 계면유체역학적인 문제를 알루미나 나노입자를 물에 분산시킨 점성과 탄성을 갖는 모델잉크를 대상으로 실험적으로 연구하였다. 형상이 다른 스크린 패턴을 통과한 잉크를 젖음성이 다른 고체면에 인쇄될 때 인쇄형상에 대하여 연구한 결과 고체면에의 인쇄 형상은 단순히 스크린 패턴이나 평형상태의 접촉각에 의하여만 결정되지 않음을 알 수 있었다. 또한 오목한 모서리와 볼록한 모서리의 차이는 점도에 따라 달라짐을 볼 수 있었다. 특히 잉크의 탄성이 테두리의 형태에 영향을 미치는 것을 알 수 있었다.