• Journal of the Korean Society for Precision Engineering
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• v.26 no.6
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• pp.114-121
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• 2009

Mobile phone is a representative personal communication tool among wireless communication devices. Recently, with the miniaturization and light-weight trend of mobile phone, the vibration motor has been replaced by coin type. The required performances of coin type vibration motor needed by user are long life, higher vibration, and thin thickness. Also the most important factor determines the performance of vibration motor is long-term reliability, which is mainly related to PCB plating technique for commutator. In this study, three types of fault were categorized to analyze the cause for malfunction of vibration motor. And, hardness and surface morphology on plating surface are also investigated to optimize the plating method and plating conditions. As a result, new plating method and conditions were proposed to increase the durability of PCB commutator.

• Resources Recycling
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• v.22 no.3
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• pp.91-99
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• 2013

Steel industry which has been accomplishes the base of our country economy, automobile and electronic industry are taking charge of the role, whose electroplating is important. Large amount of wastewater and various metal salts, including hazardous materials was generated from the electroplating pre-treatment, plating, washing and post-plating. Currently, the general wastewater follows in the environmental law and neutralization after controlling, sludge where the various metal is mixed reclaims below multiple regulative and trust it is controlling. The sludge which includes the gas price metal reclaims in the field and trust it controls. a reclamation price of land it is insufficient but and the control expense holds plentifully and it loses the gas price metal which is valuable. Consequently, The research regarding to recover a gas price metal actively from this waste water, it is advanced. A new method to recover valuable metals from electroplating wastewater synthesis of metal sulfides using topical methods utilizing iron oxidizing bacteria, reagent of sulfides and solvent extraction using an organic solvent, such as the development of the law to recover these metals and metal sulfides of wastewater using selective recovery have been studied. By using these wastewater treatment method under frequency above 95%, it has been obtained the valuable metal from the wastewater, where the metal ion of Fe, Cu, Zn and Ni complexes was mixed. As we discuss the wastewater, which has been discharged from electroplating process, it is important and will be applied to the resources of metal in the urban mine.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.5 no.2
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• pp.79-82
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• 2019

⁶¹Cu is a promising PET radiometal having favorable nuclear decay characteristics with appropriate half-life of 3.3 h. Owing its promising capabilities in radiopharmaceutical chemistry and its chemical similarities with its isotopes ⁶⁴Cu and ⁶⁷Cu, in this work we have tried to optimize the production and separation conditions of ⁶¹Cu. ⁶¹Cu was produced via (p, x) reaction with natural nickel which was electroplated on the high purity silver coated copper backing target holder. The optimization of target electrodeposition, beam energy and current modulation, target dissolution and separation were optimized in this study. Preliminary studies show that ⁶¹Cu was successfully produced and separated which can be further extended for the production of ⁶⁴Cu and ⁶⁷Cu.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.108-113
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• 2016

A miniaturized lab-scale Cu plating cell for the metallization of electronic devices was fabricated and its deposit uniformity and profile were investigated. The plating cell was composed of a polypropylene bath, an electrolyte ejection nozzle which is connected to a circulation pump. In deposit uniformity evaluation, thicker deposit was found on the bottom and sides of substrate, indicating the spatial variation of deposit thickness was governed by the tertiary current distribution which is related to $Cu^{2+}$ transport. The surface morphology of Cu deposit inside photo-resist pattern was controlled by organic additives in the electrolyte as it led to the flatter top surface compared to convex surface which was observed in the deposit grown without organic additives.

• Journal of the Korean institute of surface engineering
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• v.28 no.5
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• pp.309-319
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• 1995

The substrate patterned with the dry film has the cavity which has the $90^{\circ}$ wall angle. Electroplating Cu on this patterned substrate has the differrent shape history with the electrochemical parameters. By potential theory model, the reason of the variation of the shape change with the these parameters was investigated. The shape history could be explained by the current flow and the correlated area effects. By embedding the Ni layer between the Cu layers, shape history with the time was obtained experimentally and the results was compared with the numerical analysis by BEM. The adhesive Cr-Cu film in TAB application was etched with the various condition. The best condition for the etchant of the Cr-Cu film was found.

• Proceedings of the KWS Conference
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• 2007.11a
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• pp.227-228
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• 2007

본 연구에서는 플립칩 범프를 형성하는 여러 가지 방법 중 전해도금을 이용하여 Sn-0.7wt%Cu 솔더 범프를 형성 하고자 하였다. 전류밀도에 따른 전류 효율을 알아보기 위하여 전류밀도에 따른 실험적 증착 속도와 이론적 속도를 비교 분석 하였다. 도금 두께는 FE-SEM(Field Emission Scanning Electron Microscope)을 이용하여 측정 하였으며 최종적으로 $20{\mu}m{\times}20{\mu}m{\times}10{\mu}m$ 크기에 $50{\mu}m$ 피치를 가지는 straight wall 형 Sn-0.7wt%Cu 솔더 범프를 형성하고자 하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.137-138
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• 2011

구리 이온은 -0.40V (vs. SCE)에서 전기화학적 환원이 일어나는 반면, 니켈 이온은 -1.19V (vs. SCE)에서 전착이 발생한다. 따라서, 단일 도금욕조 내에서 Ni-Cu 합금도금층을 제조하기 위해서는 두 금속 이온종 간의 전위차를 줄여주어야 하는데, 이를 위해 본 연구에서는 $Na_3C_6H_5O_7{\cdot}2H_2O$를 착화제로 사용하였다. 다양한 Ni-Cu 합금 도금층의 조성을 얻기 위하여 기본 도금욕 내 황산니켈과 황산구리의 비율을 10:1로 설정하였다. 도금 공정 조건에 따른 합금 도금층 조성 변화를 관찰하기 위하여 도금액 pH와 교반 속도에 따른 도금층 조성 변화를 분석하였으며, 도금액의 UV-VIS과 도금층의 XRD 와 SEM 측정을 통하여 도금욕과 도금층 간의 상관 관계를 유추하였다. 본 도금액에 사용된 $Na_3C_6H_5O_7{\cdot}2H_2O$ 착화제의 효과는 pH3에서 가장 현저하였으며, pH 변화 및 교반 속도 변화를 이용하여 다양한 합금 조성을 얻을 수 있었다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.04a
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• pp.109-110
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• 2007

본 연구에서는 범프를 형성하는 여러 가지 방법중 전해도금을 이용하여 Sn-Cu 솔더 범프를 형성하고자 하였다. 기초적인 도금 특성을 알아보기 위하여 전류밀도에 따른 중착속도, 도금 시간에 따른 도금두께 등을 측정하였으며, 최종적으로는 $20{\times}20{\times}10{\mu}m$ 크기에 $50{\mu}m$피치를 갖는 Sn-Cu 솔더 범프를 형성하고자 하였다.

• Korean Journal of Materials Research
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• v.30 no.4
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• pp.160-168
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• 2020

The current density in copper electroplating is directly related with the productivity; then, to increase the productivity, an increase in current density is required. This study is based on an analysis of changes in surface characteristics and mechanical properties by applying the addition of Alcian Blue (AB, C₅₆H₆₈Cl₄CuN₁₆S₄). The amount of Alcian Blue in the electrolytes is changed from 0 to 100 ppm. When Alcian Blue is added at 20 ppm, a seed layer is formed homogeneously on the surface at the initial stage of nucleation. However, crystals electroplated in electrolytes with more than 40 ppm of Alcian Blue are observed to have growth in the vertical direction on the surface and the shapes are like pyramids. This tendency of initial nucleation formation causes protrusions when the thickness of copper foil is 12 ㎛. Thereafter, a lot of extrusions are observed on the group of 100 ppm Alcian Blue. Tensile strength of groups with added Alcian Blue increased by more than 140% compare to no-addition group, but elongation is reduced. These results are due to the decrease of crystal size and changes of prior crystal growth plane from (111) and (200) to (220) due to Alcian Blue.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.3
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• pp.79-84
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• 2010

Formation of TSV (Through-Si-Via) with an Au seed layer and Cu filling to the via, simplification of bumping process for three dimensional stacking of Si dice were investigated. In order to produce the via holes, the Si wafer was etched by a DRIE (Deep Reactive Ion Etching) process using $SF_6$ and $C_4F_8$ plasmas alternately. The vias were 40 ${\mu}m$ in diameter, 80 ${\mu}m$ in depth, and were produced by etching for 1.92 ks. On the via side wall, a dielectric layer of $SiO_2$ was formed by thermal oxidation, and an adhesion layer of Ti, and a seed layer of Au were applied by sputtering. Electroplating with pulsed DC was applied to fill the via holes with Cu. The plating condition was at a forward pulse current density of 1000 mA/$dm^2$ for 5 s and a reverse pulse current density of 190 mA/$dm^2$ for 25 s. By using these parameters, sound Cu filling was obtained in the vias with a total plating time of 57.6 ks. Sn bumping was performed on the Cu plugs without lithography process. The bumps were produced on the Si die successfully by the simplified process without serious defect.