• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.132-133
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• 2014

구리도금 및 적절한 어닐링 공정을 통해 수nm 크기의 초기 도금 미세조직과 수${\mu}m$정도의 결정립 크기를 갖는 재결정이 진행된 결정립이 병존하는 도금막 샘플을 제작하였다. 전기 비저항 측정과 EBSD를 통해 결정립 성장 분율을 측정하였으며 다양한 사이즈와 결정 방향을 갖는 결정립에 대해 질산용액을 이용하여 화학적 에칭방법을 통해 간접적으로 각 구리원자의 화학적 안정성을 평가할 수 있었다. 결과적으로 결정립이 클수록 에칭속도가 느린 것을 확인하였으며, 주요 원인으로 결정립계면이 우선적으로 에칭되는 것이 관찰되었다. 즉, 결정립의 크기가 작을수록 결정립계면의 비율이 커서 에칭속도가 증가하고 Nanosize의 초기 결정립이 빨리 에칭되는 것이 확인되었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.408-411
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• 2003

최근 활발하게 연구가 진행되고 있는 마이크로 인덕터는 자기 데이터 저장을 위한 헤드, 자기장 센서, 마이크로 변압기와 휴대폰의 수동 소자와 같은 다양한 분야에 이용되고 있다. 마이크로 인덕터를 제작하기 위해 UV-LIGA 공정을 개발하였다. 도금 공정을 이용하여 마이크로 인덕터의 철심과 구리선 제작하였다. 도금 공정을 위해 필요한 마이크로 몰드는 여러 종류의 thick photoresist를 이용하여 저응력 공정으로 제작하였다. 도금 공정을 이용하여 toroid형 마이크로 인덕터를 제작하였다. 도금 공정에서 발생 할 수 있는 응력을 최소화할 수 있는 공정을 개발하였다.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.548-554
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• 2016

In this study, semi-aqueous solutions containing carboxylic acids such as oxalic acid (OA), lactic acid (LA) and citric acid (CA) were formulated for the removal of copper etching residues produced at the interconnection process, and their characteristics were analyzed. Carboxylic acids in the solutions were apt to form various copper complexes according to the value of pH. Semi-aqueous solution containing 10 wt% CA showed the lowest etching rate of copper in the range from pH2 to pH7 and the highest selectivity in the range of pH 2 to pH 4. However, the cleaning solution containing 10 wt% LA revealed the superior selectivity at the range from pH 5 to pH 7. Appropriate selection of carboxylic acid should be required to improve the performance of cleaning solution. In the case of CA, the etching selectivity of copper oxide complex to copper was increased with the concentration of CA in the solution, when the solutions contain over 5 wt% CA, the copper interconnection layer has a metallic copper surface more than 88% in the area. The result shows that CA contained semi-aqueous solution has a relatively good cleaning ability.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.2
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• pp.17-21
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• 2008

The electroless plating of copper and tin were investigated for the fabrication of Sn-Cu bump. Copper and tin were electroless plated in series on $20{\mu}m$ diameter copper via to form approximately $10{\mu}m$ height bump. In electroless copper plating, acid cleaning and stabilizer addition promoted the selectivity of bath on the copper via. In electroless tin plating, the coating thickness of tin was less uniform relative to that of electroless copper, however the size of Sn-Cu bump were uniform after reflow process.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.179-179
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• 2010

다양한 분야에서 확산 방지막은 소자의 신뢰성 향상에 중요한 역할을 하고 있다. 최근 반도체에 적용되기 시작한 구리 배선 형성 공정에서도 실리콘이나 실리콘 산화막으로 구리가 확산하는 것을 방지하는 기술이 중요한 부분을 차지하고 있다. 기존 physical vapor deposition (PVD)법을 이용한 $TaN_x$ 확산 방지막 형성 기술이 성공적으로 적용되고 있으나 반도체의 최소선폭이 지속적으로 감소함에 따라 한계에 다다르고 있다. 20 nm 급과 그 이하의 구리 배선을 위해서는 5 nm 이하의 매우 얇고 높은 피복 단차율을 가진 확산 방지막 형성 기술이 요구된다. 또한, 요구 두께의 감소에 따라 더 우수한 확산 방지 특성이 요구된다. Atomic layer deposition (ALD)은 박막의 정교한 두께 조절이 가능하며 높은 종횡비를 가지는 구조에서도 균일한 박막 형성이 가능하다. 이번 연구에서는 다른 질소 함량을 가진 $TaN_x$ 박막을 Tertiarybutylimido tris (ethylamethlamino) tantalum (TBITEMAT) 전구체와 $H_2+N_2$ 반응성 플라즈마를 사용하여 plasma enhanced atomic layer deposition (PEALD) 법으로 형성하였다. 박막 내질소 함량에 따라 $TaN_x$의 상 (phase)과 미세구조 변화가 관찰되었고, 이러한 물성의 변화는 확산 방지 특성에 영향을 주었다. TEM (Transmission electron microscopy)과 SEM (scanning electron microscope), XPS (x-ray photoelectron spectroscopy)를 통해 $TaN_x$의 물성을 분석하였고, 300 도에서 700 도까지 열처리 후 XRD (x-ray deffraction)와 I-V test를 통해 확산 방지막의 열적 안정성이 평가되었다. PEALD를 통해 24 nm 크기의 trench 기판 위에 약 4 nm의 $TaN_x$ 확산 방지막이 매우 균일하게 형성할 수 있었으며 향후 구리 배선에 효과적으로 적용될 것으로 예상된다.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.3 no.1
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• pp.78-90
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• 1993

This study was designed obtain and early detection the workers exposed to excessive copper dust and also to present biological exposure index. The exposed group consisted of 62 male workers at the metallurgy workplaces. To evaluate the degree of individual exposure the copper dust, each personal air sampling was collected. Biological exposures in the exposed group was quantified for the blood and urine copper levels using flameless atomic absorption spectrophotometer. The control group consisted of 70 male adults with the history of nonexposure to copper by the inhalation occupationally. The average concentration of copper in blood and urine of the exposed group was $49.44{\pm}8.90(29.05-80.63){\mu}g/dl$, $39.99{\pm}11.04(29.62-80.63){\mu}g/l$ respectively. The average concentration of air borne copper was $0.48{\pm}0.31(0.03-1.18)mg/m^3$. The average concentration of blood and urine copper in the control group was $42.93{\pm}5.84(25.05-57.85){\mu}g/dl$, $33.02{\pm}13.38(12.00-82.05){\mu}g/l$ respectively. The difference observed in the average concentration of blood and urine copper of the exposed and control groups was statistically significant seperately (blood copper, p<0.05 ; urine copper, p<0.05). The relationship between the individual exposure concentration of air borne copper and the concentration of the blood and urine copper was statistically significant, respectively (blood copper, r=0.54, p<0.05 ; urine copper, r=0.37, p<0.05). The relationship between the working duration and the concentration of blood and urine was not statistically significant respectively (blood copper, r=0.14 ; urine copper, r=0.12). The relationship between the age and the concentration of blood and urine copper was statistically not significant respectively (blood copper, r=013 ; urine copper, r=-0.06). The relationship between blood and urine copper concentration in the exposed group was statistically significant (r=0.62, p<0.05), and the relationship between blood and urine copper concentration in the control group was also statistically significant (r=0.39, p<0.05).

• Journal of the Microelectronics and Packaging Society
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• v.18 no.2
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• pp.43-48
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• 2011

The maximum current density of copper electrorefining is 350 A/$m^2$ and the higher current density is required to promote the copper productivity. The 1000 A/$m^2$ high current density is possible when rotating disc electrode is employed to reduce diffusion thickness. The copper electroplating with 1000 A/$m^2$ is possible at 400 rpm. Thiourea and glue were used to improve the electrodeposition behaviors during copper electrorefining process. Potentiodynamic polarization tests were conducted to investigate the effects of additives on copper electrodeposition. Galvanostatic tests were also conducted at 1000 A/$m^2$. Copper were electroplated on cylindrical rotating electrodes to give the uniform flow on the electrode surface. The lowest surface roughness was obtained when 16 ppm thiourea was added to the electrolytes. The surface roughness was increased with glue concentration. The surface hardness was not influenced by addition of glue. The copper nuclei were getting smaller with thiourea concentration, however there is no glue effects on copper nucleation.

• Journal of the Korea Organic Resources Recycling Association
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• v.7 no.2
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• pp.25-34
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• 1999

The effects of copper on the anaerobic degradation of propionate were studied using anaerobic batch reactors. The apparent inhibitory effects of copper on the anaerobic degradation of propionate could be observed from behaviors of intermediates, ultimate methane yield(UMY) and specific methanogenic activity(SMA) There was little inhibition at the concentration of $2.5mg\;Cu^{2+}/L$. Beyond this concentration, the inhibitory effects increased with increasing dose of coppers. The 50% inhibition of UMY and SMA occurred at copper dosage of 33.8 and $24.1mg\;Cu^{2+}/gVSS$, respectively. The inhibitory effect based on the UMY was gradually reduced with the operation time dueprobably to the acclimation of microorganisms and/or binding of the added copper by ligands(and possibly ion exchange sites)contained on the cell membrane and extracellular polymer matrix whereas it based on the SMA might exclude the this phenomena. Therefore, the methodology for interpretation of inhibition data based on the SMA was more accurated than the UMY. There was no inhibitory effect in batch reactors supplemented with sulfate due to an antagonistic action of the sulfate reducing bacteria. Propionate degradation was initially retarded for copper inhibited samples but it gradually degraded afterward. Based on the mass removal considering take into account the propionate to acetate conversion, propionate degradation may appeal more affected than acetate. This result revealed that the hydrogenotrophic methanogens were the most affected by copper.

• Journal of the Microelectronics and Packaging Society
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• v.13 no.2 s.39
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• pp.9-13
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• 2006

The copper lines in COF are usually fabricated by subtractive method. As the width of lines are smaller, the subtractive method has a lateral etching problems. In semi-additive method, copper lines are fabricated by lithographic technique followed by electroplating method. Fine line patterns of $10-40{\mu}m$ were used for this study. Two different types of thick photoresist, AZ4620 and PMER900, were employed for PR mold. Copper lines were fabricated by electroplating method. The crack were found in fine copper lines due to high residual stress when normal copper electroplating bath were used. The via filling copper electroplating bath were replaced the normal electroplating bath and then cracks were not found in the fine copper lines. During substrate etching, the lateral etching of copper lines were not occurred.

• Journal of the Korean Vacuum Society
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• v.6 no.1
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• pp.28-35
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• 1997

Effects of rapid thermal annealing on the characteristics of Cu films deposited from the (hfac)Cu(VTMS) precursor and on the barrier properties of TiN layers were studied. By the post-annealing, the electrical characteristics of Cu/TiN and the microstructures of Cu films were significantly changed. The properties of Cu films were more sensitive to the annealing temperature than the annealing time. Sheet resistance started to increase above $400^{\circ}C$, and the interreaction between Cu and Ti and the oxidation of Cu layer were observed above $600^{\circ}C$. The grain growth of Cu with the (111) preferred orientation was found to be most pronounced at $500^{\circ}C$. It revealed that the optimum annealing conditions for MOCVD-Cu/PVD-TiN structures to enhance the electrical characteristics without degradation of TiN barriers were in the range of $400^{\circ}C$.