• Journal of the Korean Vacuum Society
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• v.3 no.1
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• pp.65-70
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• 1994

본 논문에서는 Al-1%Si 박막금속배선에서 국부적 전류 크라우딩 효과 및 박막금속배선의 길이 에 따른 수명의 변화, 그리고 이층금속배선에서의 전계효과를 연구하였다. 전류 크라우딩 효과에 으한 박막금속 배선의 수명감소를 관찰하기 위해 넓은 도선과 좁은 도선이 반복적으로 연결되어 있는 구조의 금속배선과 톱니 형태의 금속배선을 제작하였다. 길이에 따른 박막금속배선의 수명변화를 연구하기 위 해 100, 400, 800, 1200 그리고 $1600mu$m의 길이를 갖는$ 3\mu$m 선폭의 박막금속배선을 각각 제작하였다. Al-1%Si 박막금속배선에 인가된 전류밀도는 3.5~4.5x106 A/cm2이었다. 이층금속배선에서 전계에 의한 수명의 변화를 살펴보기 위해 두 금속 배선 사이에 0, $\pm$30, $\pm$60V의 전계를 인가하고 상층 금속배선에 1.75x106 A/cm2 전류 밀도를 조사하였으며 발생한 결함 현상에 대한 분석은 광학현미경과 주사전자현미 경으로 관찰하였다. 주요 결론으로는 박막금속배선에서 전류 크라우딩 효과는 수명의 감소를 초래하며 박막금속배선의 길이가 증가함에 따라 수명은 급격하게 감소하다가 포화된다. 중첩된 이층금속배선에서 는 전계효과에 의한 금속배선의 수명감소현상이 가속된다.

• Journal of Pharmaceutical Investigation
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• v.41 no.6
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• pp.337-345
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• 2011

The objective of this work is to investigate the effect of chemical enhancer and current on the flux of donepezil hydrochloride (DH) through skin. Ethanol and N-methyl pyrrolidone (NMP) were used as chemical enhancers in combination with iontophoresis. We also have studied the effect of pH on flux and evaluated the role of electroosmosis. In vitro flux study was performed at $33^{\circ}C$, using side-by-side diffusion cell and full thickness hairless mouse skin. Passive flux of DH without enhancer was very small. As the concentration of enhancer increased, passive flux increased. After current application, flux increased markedly and the time to reach maximum decreased. Without enhancer, maximum flux was about 50 fold larger than that obtained without current. These results indicate that electromigration is playing a major role for the transport. As the enhancer concentration increased, flux also increased. NMP and ethanol increased not only the passive delivery, but also the iontophoretic delivery. Flux results indicate that ethanol has better ability than NMP in enhancing the transport of DH. The magnitudes of increase in flux by these enhancers indicate that there is a large synergistic effect in flux enhancement. Flux results from pH study showed that electroosmotic flow is reversed at low pH and the flux is hindered. These results provided some information on the flux enhancing ability of ethanol and NMP in combination with iontophoresis. The data also provided some mechanistic insights into the role of electromigration and electroosmosis on flux through skin.

• Journal of Soil and Groundwater Environment
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• v.16 no.5
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• pp.18-23
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• 2011

The electrokinetic transport characteristics of salts were investigated using nitrate and sulfate accumulated saline greenhouse soil. Within 8 days, 95% of nitrate was removed from the soil, while sulfate removal was 19% for 8 days. The low removal of sulfate came from adsorption reaction on the soil particles or organic matter and precipitation with calcium. Divalent cations such as calcium and magnesium were transported toward cathode via electromigration, and most monovalent cation such as potassium was removed. The pattern of residual electrical conductivity was similar with that of sulfate. Based on the results, electrokinetic technique is effective to restore nitrate-accumulated saline soil, but is not effective to restore sulfate-accumulated soil.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.121-121
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• 2000

반도체 산업의 발달에 따라 소자의 보다 빠른 동작 속도와 큰 집적도를 갖은 ULSI 구조를 얻기 위해, 새로운 금속배선 재료가 요구되고 있다. 기존의 금속 배선인 Al 및 Al 합금은 비교적 낮은 비저항과 박막형성의 용이함으로 인하여 현재까지 금속배선 재료로 사용되고 있으나, 고집적화에 따라 RC Time Delay와 Electromigration의 문제점을 들어내었다. 이러한 문제를 해결할 새로운 배선 재료로 Al보다 낮은 비저항을 가지며, electromigration 저항성을 갖는 Cu 금속배선 재료가 활발히 연구되고 있다. 본 실험에서는 (100) Si 웨이퍼를 기판으로 사용하였으며, 각층은 SiO2/Si3N4/EP Cu/Seed Cu/ TaN/SiO2/Si wafer 상태로 증착하였다. 확산방지막으로 TaN을 사용하였고, seed Cu는 sputtering 으로 증착하였으며, seed Cu 만으로 된 박막과 seed Cu + electro plating Cu로 구성된 박막을 제작하였다. 제작 완료된 박막은 N2 분위기에서 20$0^{\circ}C$ 120 min, 45$0^{\circ}C$ 60min 동안 열처리하여 Cu 박막의 조직 변화를 TEM 및 여러 분석방법을 이용하여 분석하였다. Plan-view TEM결과, 45$0^{\circ}C$, 60min 열처리함에 따라 결정립 성장이 일어난 것을 확인 할 수 있었다. 그러나, 성장후에도 twin boundary, stacking fault, dislocation, small defect 등은 여전히 남아 있음이 관찰된다. 그림 1(a)는 as-deposit 상태이며, 그림 1(b)는 45$0^{\circ}C$, 60min 열처리한 plan-view TEM 사진이다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.123-124
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• 2005

We investigated the effect of a Ta/TaN Cu diffusion barrier existence on the reliability and the electrical performance of Cu dual-damascene interconnects. A high EM performance in Cu dual-damascene structure was observed the BCV(barrier contact via) interconnect structure to remain Ta/TaN barrier layer. Via resistance was decreased DCV interconnect structure by bottomless process. This structure considers that DCV interconnect structure has lower activation energy and higher current density than BCV interconnect structure. The EM failures by BCV via structure were formed at via hole, but DCV via structure was formed EM fail at the D2 line. In order to improve the EM characteristic of DCV interconnect structure by bottomless process, after Ta/TaN diffusion barrier layer in via bottom is removed by Ar+ resputtering process, it is desirable that Ta thickness is thickly made by Ta flash process.

• Journal of the Korean Vacuum Society
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• v.9 no.3
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• pp.267-272
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• 2000

Electroplating Cu was deposited on Si(100) wafer after seed Cu was deposited by sputtering first. TaN was deposited as a diffusion barrier before depositing the seed Cu. Electroplating Cu thin films show highly (111)-oriented microstructure for both before and after annealing at $450^{\circ}C$ for 30min and no copper silicide was detected in the same samples, which indicates that TaN barrier layer blocks well the Cu diffusion into silicon substrate. After annealing the electroplating Cu film up to $450^{\circ}C$, the Cu film became columnar from non-columnar, its grain size became larger about two times, and also defects density of stacking faults, twins and dislocations decreased greatly. Thus the heat treatment will improve significantly electromigration property caused by the grain boundary in the Cu thin films.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.195.1-195.1
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• 2013

Cu는 금속 박막재료로서 높은 전기전도성을 지니고 있을 뿐만 아니라 Ag, Al, Pt 등 보다 비용이 저렴하여, 높은 전기전도성을 필요로 하는 박막 재료로써 폭넓게 사용되고 있다. 그러나, 낮은 기계적 특성을 지니고 있어서 interconnect와 같은 작은 단면적의 배선재료로 사용될 경우, 높은 전류밀도에 따른 electromigration 현상에 의하여 hillock 또는 void의 형성 등 박막재료의 변형이 생기게 되어서 전자소자의 수명이 단축된다는 단점이 있다. TiN은 금속재료 못지않은 높은 전기 전도성을 지니고 있을 뿐만 아니라, 금속재료에 비하여 높은 기계적 특성과 녹는점을 지니고 있어 다양한 분야로 사용되고 있다. 본 연구에서는 Cu와 TiN composite 박막을 soda-lime glass위에 증착하여 낮은 비저항 뿐만 아니라 Cu와 비교하여 기계적 특성이 향상된 박막을 제작하고자 하였다. Cu와 TiN composite 박막 증착을 위하여 DC reactive magnetron co-sputtering 장비를 사용하였으며, Cu와 Ti 타겟 power, Ar:N2 유량비(Flow rate)을 변화시켜 Cu와 Ti의 조성비 및 TiN의 결정성을 조절하였고, 이를 통하여 박막의 TiN 조성에 따른 낮은 비저항 값과 순수한 Cu 박막과 비교하여 높은 기계적 특성을 지닌 Cu-TiN 박막을 증착하였다. Cu-TiN composite 박막의 구조 및 조성은 SEM (Scanning Electron Microscope), EDS (Energy Dispersive Spectrometer), XPS (X-ray Photoelectron Spectroscopy)장비를 사용하여 분석하였으며, 전기전도도는 4-point probe를 사용하여 측정하였고, Knoop hardness 측정방법을 사용하여 박막의 기계적 특성을 측정하였다.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.2
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• pp.81-89
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• 2022

The in-situ electromigration(EM) and annealing test were performed at 110, 130, and 150℃ with a current density of 1.3×10⁵ A/cm² conditions to investigate the effect of non-conductive film (NCF) on growth kinetics of intermetallic compound (IMC) in Cu/Ni/Sn-2.5Ag microbump. As a result, the activation energy of the Ni₃Sn₄ IMC growth in the annealing and EM conditions according to the NCF application was about 0.52 eV, and there was no significant difference. This is because the growth rate of Ni-Sn IMC is much slower than that of Cu-Sn IMC, and the growth behavior of Ni-Sn IMC increases linearly with the square root of time, so it has the same reaction mechanism dominated by diffusion. In addition, there is no difference in the activation energy of the Ni₃Sn₄ IMC growth because the EM resistance effect of the back stress according to the NCF application is not large.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.3
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• pp.21-30
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• 2012

Technology trend and application of laser fuse, anti-fuse, and eFUSE as well as the structure, programming mechanism, and reliability of eFUSE have been reviewed. In order to ensure eFUSE reliability in the field, a sensing circuit trip point consistent with the fuse resistance distribution, process variation, and device degradation in the circuit such as hot carrier or NBTI, as well as fuse resistance reliability must be considered to optimize and define a reliable fuse programming window.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.02a
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• pp.185.2-185.2
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• 2009