• 마이크로전자및패키징학회지
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• 제22권2호
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• pp.47-53
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• 2015

인쇄회로기판 솔더 상부 및 하부 접합부의 서로 다른 표면처리 조건에 따른 Sn-3.0Ag-0.5Cu (SAC305) 접합부의 열처리 및 전류 인가에 따른 금속간 화합물 성장거동을 비교하기 위하여 in-situ 미세구조분석 및 electromigration (EM) 수명평가를 실시하였다. 솔더 접합 직후, 상부 접합부의 electroless nickel immersion gold (ENIG) 표면처리에서는 $(Cu,Ni)_6Sn_5$, 하부 접합부의 organic solderability preservative (OSP) 표면처리에서는$ Cu_6Sn_5$, $Cu_3Sn$ 금속간 화합물이 접합 계면에서 생성되었다. EM 수명평가 결과 온도 $130^{\circ}C$, 전류밀도 $5.0{\times}10^3A/cm^2$ 하에서 평균파괴시간이 약 78.7 hrs으로 도출되었고, 하부 OSP 표면처리에서 전자가 솔더로 빠져나가는 부분에서 Cu의 소모에 의한 단락이 주 손상기구로 확인되었다. In-situ 주사전자현미경을 통해 계면 미세구조 분석 결과 상부 접합부 ENIG 표면처리에서 전자의 방향에 따른 미세구조의 큰 차이가 없고 뚜렷한 손상이 관찰되지 않았으나, 하부 접합부 OSP 표면처리의 경우 전자가 솔더로 유입되는 부분에서 빠른 Cu 소모로 인한 보이드 성장이 관찰되었다. 따라서, SAC305무연솔더 접합부에서 ENIG 표면처리가 OSP 표면처리보다 보다 우수한 EM확산방지막 역할을 하여 금속간 화합물 성장을 억제하고 보다 우수한 EM 신뢰성을 보이는 것으로 판단된다.

• 한국재료학회지
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• 제14권1호
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• pp.46-51
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• 2004

The annealing of a Cu(4.5at.% Mg)/$SiO_2$/Si structure in ambient $O_2$, at 10 mTorr, and $300-500^{\circ}C$, allows for the outdiffusion of the Mg to the Cu surface, forming a thin MgO (15 nm) layer on the surface. The surface MgO layer was patterned, and successfully served as a hard mask, for the subsequent dry etching of the underlying Mg-depleted Cu films using an $O_2$ plasma and hexafluoroacetylacetone [H(hfac)] chemistry. The resultant MgO/Cu structure, with a taper slope of about $30^{\circ}C$ shows the feasibility of the dry etching of Cu(Mg) alloy films using a surface MgO mask scheme. A dry-etched Cu(4.5at.% Mg) gate a-Si:H TFT has a field effect mobility of 0.86 $\textrm{cm}^2$/Vs, a subthreshold swing of 1.08 V/dec, and a threshold voltage of 5.7 V. A novel process for the dry etching of Cu(Mg) alloy films, which eliminates the use of a hard mask, such as Ti, and results in a reduction in the process steps is reported for the first time in this work.

• 전기화학회지
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• 제20권1호
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• pp.1-6
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• 2017

본 연구에서는 구리 배선 공정에서 구리 씨앗층 표면에 형성되는 구리 자연산화물을 제거하는 표면 전처리가 후속 구리 전착에 미치는 영향을 살펴보았다. 구리 배선 공정의 화학적 기계적 연마 공정에서 사용하는 citric acid 기반의 용액을 구리 표면 전처리 과정에 적용하여 표면에 존재하는 구리 자연 산화물을 제거하였고, 용액 조성 변화를 통해 산화물 제거의 선택성을 높여 구리 씨앗층의 손실을 최소화하였다. 또한 표면 전처리 후 구리 전해 전착과 무전해 전착을 시도하여 전착한 박막의 비저항, 표면 거칠기 등의 성질을 비교하고, 이를 통해 선택적으로 구리 산화물을 제거한 이후에 전착된 박막의 비저항과 표면 거칠기가 가장 낮게 나타남을 확인하였다.

• 한국표면공학회지
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• 제30권2호
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• pp.111-120
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• 1997

The growth kinetion of $CuCl_x$ layer on Cu was investigated using $Cl_2$ gas with/without plasma. The etching kinetics ofit was also studied, in which PEt3 gas as well as $Cl_2$ gas were used. when plasma and DC bias were applied, not only the growth rate of $CuCl_x$ layer but also the surface concentration of Cl in $CuCl_x$ layer drastically increased. The growth mode is divided into three regimes, where the thinkness $CuCl_x$ layer ise proportional to t, lo9g $T^{1/2}$ , respectively, whether plasma, is applied or not. These three regime. It is also identified that the eath rate of Cu is drastically increased as the $Cl_2$ pressure is increased. However, when plasma and DC bias were applied, the etching rate is decreased, and ClCu-P-U layer is formed. in addition, as the etching time is increased, the surface concentration of Cl is increased and $CuCl_2$ formed partially.

• 한국전기전자재료학회논문지
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• 제21권10호
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• pp.934-937
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• 2008

Organic field-effect transistors (OFETs) are of interest for use in widely area electronic applications. We fabricated a copper phthalocyanine (CuPc) based field-effect transistor with different metal electrode. So we need the effect of the substituent group attached to the phthalocyanine on the surface potential was investigated by Kelvin probe method with varying temperature of the substrate. We were obtained the positive shift of the surface potential for CuPc thin film. We observed the electron displacement at the interface between Au electrode and CuPc layer and we were confirmed by the surface potential measurement.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.492-493
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• 2007

Organic field-effect transistors (OFETs) are of interest for use in widely area electronic applications. We fabricated a copper phthalocyanine(CuPc) based field-effect transistor with different metal electrode. So we need the effect of the substituent group attached to the phthalocyanine on the surface potential was investigated by Kelvin probe method with varying temperature of the substrate. We were obtained the positive shift of the surface potential for CuPc thin film. We observed the electron displacement at the interface between Au electrode and CuPc layer and we were confirmed by the surface potential measurement.

• 상하수도학회지
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• 제37권4호
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• pp.177-186
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• 2023

Perfluorooctanoic acid(PFOA) was one of widely used per- and poly substances(PFAS) in the industrial field and its concentration in the surface and groundwater was found with relatively high concentration compared to other PFAS. Since various processes have been introduced to remove the PFOA, adsorption using GAC is well known as a useful and effective process in water and wastewater treatment. Surface modification for GAC was carried out using Cu and Fe to enhance the adsorption capacity and four different adsorbents, such as GAC-Cu, GAC-Fe, GAC-Cu(OH)₂, GAC-Fe(OH)₃ were prepared and compared with GAC. According to SEM-EDS, the increase of Cu or Fe was confirmed after surface modification and higher weight was observed for Cu and Fe hydroxide(GAC-Cu(OH)₂ and GAC-Fe(OH)₃, respectively). BET analysis showed that the surface modification reduced specific surface area and total pore volumes. The highest removal efficiency(71.4%) was obtained in GAC-Cu which is improved by 17.9% whereas the use of Fe showed lower removal efficiency compared to GAC. PFOA removal was decreased with increase of solution pH indicating electrostatic interaction governs at low pH and its effect was decreased when the point of zero charges(pzc) was negatively increased with an increase of pH. The enhanced removal of PFOA was clearly observed in solution pH 7, confirming the Cu in the surface of GAC plays a role on the PFOA adsorption. The maximum uptake was calculated as 257 and 345 ㎍/g for GAC and GAC-Cu using Langmuir isotherm. 40% and 80% of removal were accomplished within 1 h and 48 h. According to R², only the linear pseudo-second-order(pso) kinetic model showed 0.98 whereas the others obtained less than 0.870.

• 한국재료학회지
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• 제19권1호
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• pp.13-17
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• 2009

A semi-empirical method to estimate the surface tension of molten alloys at different oxygen partial pressures is suggested in this study. The surface tension of molten Ag-Sn and Ag-Cu alloys were calculated using the Butler equation with the surface tension value of pure substance at a given oxygen partial pressure. The oxygen partial pressure ranges were $2.86{\times}10^{-12}$－$1.24{\times}10^{-9}$ Pa for the Ag-Sn system and $2.27{\times}10^{-11}$－$5.68{\times}10^{-4}$ Pa for the Ag-Cu system. In this calculation, the interactions of the adsorbed oxygen with other metallic constituents were ignored. The calculated results of the Ag-Sn alloys were in reasonable accordance with the experimental data within a difference of 8%. For the Ag-Cu alloy system at a higher oxygen partial pressure, the surface tension initially decreased but showed a minimum at $X_{Ag}$ = 0.05 to increase as the silver content increased. This behavior appears to be related to the oxygen adsorption and the corresponding surface segregation of the constituent with a lower surface tension. Nevertheless, the calculated results of the Ag-Cu alloys with the present model were in good agreement with the experimental data within a difference of 10%.

• 한국진공학회지
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• 제15권1호
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• pp.45-49
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• 2006

깨끗한 Cu(110)와 산소가 흡착된 Cu(110) 표면에 Cu 성장에 의한 광학적 이방성의 변화를 RDS를 이용하여 연구하였다. 250K에서 Cu를 성장하면서 성장 모드와 산소의 계면활성제 효과를 확인하였다. 두 표면에 Cu를 성장하면서 4,25eV 봉우리의 규칙적인 변화를 확인하여 layer-by-layer 모드를 확인하였다.

• 대한금속재료학회지
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• 제48권1호
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• pp.57-61
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• 2010

Nanosized surface structures of Cu powders were investigated at the atomic scale by field-emission transmission electron microscope techniques. The nanoscale surface oxide layer on the Cu powder was analyzed to be the $CU_2O$ phase by electron diffraction pattern and electron energy-loss spectroscopy. In addition, it was found from high-resolution transmission electron microscopy study that there are formed no surface oxide layers on the surface of alkanethiol coated Cu powders.