• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.12
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• pp.1352-1355
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• 2004

We have applied front contact metallization of plated nickel and copper for high efficiency passivated emitter rear contact(PERC) solar cell. Ni is shown to be a suitable barrier to Cu diffusion as well as desirable contact metal to silicon. The plating technique is a preferred method for commercial solar cell fabrication because it is a room temperature process with high growth rates and good morphology. In this system, the electroless plated Ni is utilized as the contact to silicon and the plated Cu serves as the primary conductor layer instead of traditional solution that are based on Ti/Pd/Ag contact system. Experimental results are shown for over 20 % PERC cells with the Plated Ni/Cu contact system for good performance at low cost.

• Korean Journal of Materials Research
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• v.10 no.12
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• pp.853-863
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• 2000

In this study, a new UBM materials system for solder flip chip interconnection of Cu pads were investigated using electroless copper (E-Cu) and electroless nickel (E-Ni) plating method. The interfacial reaction between several UBM structures and Sn-36Pb-2Ag solder and its effect on solder bump joint mechanical reliability were investigated to optimife the UBM materials design for solder bump on Cu pads. Fer the E-Cu UBM, continuous coarse scallop-like $Cu_{6}$ $Sn_{5}$ , intermetallic compound (IMC) was formed at the solder/E-Cu interface, and bump fracture occurred this interface under relative small load. In contrast, Fer the E-Ni/E-Cu UBM, it was observed that E-Ni effectively limited the growth of IMC at the interface, and the Polygonal $Ni_3$$Sn_4$ IMC was formed because of crystallographic mismatch between monoclinic $Ni_3$$Sn_4$ and amorphous E-Ni phase. Consequently, relatively higher bump adhesion strength was observed at E-Ni/E-Cu UBM than E-Cu UBM. As a result, it was fecund that E-Ni/E-Cu UBM material system was a better choice for solder flip chip interconnection on CU PadS.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.387.2-387.2
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• 2014

최근 이동통신 LED 에너지 자동차 산업분야에서 제품의 고기능화 고성능화를 위한 신소재 개발 및 친환경적인 신공정 개발에 있어, PI 또는 PET와 같은 유연성 소재 위에 선택적 패턴 도금 기술, 고기능성 나노/복합 도금 등이 주목 받고 있다. 또한 전 세계적으로 유해물질의 수 출입 규제 움직임이 강력하게 제기되고 있다. 본 연구에서는 유연성 소재인 PET 위에 친환경적 방법으로 구리를 선택적으로 도금하기 위한 실험을 진행하였다. 준비된 PET 필름 위에 Ag paste를 Screen Printing법을 이용하여 Ag 전극을 패턴하고, 그 위에 무전해 도금방식을 이용하여 Ni과 Cu가 도금 되도록 하였다. Ni 무전해 도금은 pH6.5, 65도에서 시행되었으며, Cu 무전해 도금은 환경규제물질인 포름알데히드 대신에 차아인산나트륨을 사용하여 70도에서, 중성근처의 pH 농도(pH7과 pH8)에서 시행되었다. 이들 다층 박막에 대해 X-ray diffraction (XRD), SEM (Scanning Electron Microscope), XPS (X-ray Photoelectron Spectroscopy) 등을 이용하여 물리-화학적/전기적 특성들을 이용하여 조사 분석하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.192-193
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• 2007

An evaporated Ti/Pd/Ag contact system is most widely used to make high-efficiency silicon solar cells, however, the system is not cost effective due to expensive materials and vacuum techniques. Commercial solar cells with screen-printed contacts formed by using Ag paste suffer from a low fill factor and a high shading loss because of high contact resistance and low aspect ratio. Low-cost Ni and Cu metal contacts have been formed by using electro less plating and electroplating techniques to replace the Ti/Pd/Ag and screen-printed Ag contacts. Ni/Cu alloy is plated on a silicon substrate by electro-deposition of the alloy from an acetate electrolyte solution, and nickel-silicide formation at the interface between the silicon and the nickel enhances stability and reduces the contact resistance. It was, therefore, found that nickel-silicide was suitable for high-efficiency solar cell applications. Cu was electroplated on the Ni layer by using a light induced plating method. The Cu electroplating solution was made up of a commercially available acid sulfate bath and additives to reduce the stress of the copper layer. In this paper, we investigated low-cost Ni/Cu contact formation by electro less and electroplating for crystalline silicon solar cells.

• Journal of the Korean institute of surface engineering
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• v.43 no.2
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• pp.64-72
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• 2010

CuSnZn electroplating was investigated as alternative to Ni plating. Evaluation of electrolyte and plating process was performed to control physical characteristics of the film, and to collect practical data for application. Hull-cell test was conducted for basic comparison of two commercialized products and developed product. Based on hull-cell test results, long term test of three electrolytes was performed. Various analysis on long term tested electrolyte and samples have been done. Reliable and practical data was collected using FE-SEM (FEI, Sirion), EDX (ThermoNoran SIX-200E), ICP Spectrometer (GBC Scientifi c, Integra XL), FIB (FEI, Nova600) for anlysis. Physical analysis and reliability test of the long term tested film were also carried out. Through this investigation plating time, plating speed, electrolyte composition, electrolyte metal consumption, hardness and corrosion resistance has been compared. This set of data is used to predict and control the chemical composition of the film and modify the physical characteristics of the CuSnZn alloy.

• Korean Journal of Metals and Materials
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• v.48 no.11
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• pp.1041-1046
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• 2010

The reactions between a Sn-3.0Ag-0.5Cu solder alloy and electroless Ni/electroless Pd/immersion Au (ENEPIG) surface finishes with various Pd layer thicknesses (0, 0.05, 0.1, 0.2, $0.4{\mu}m$) were examined for the effect of the Pd layer on the massive spalling of the $(Cu,Ni)_6Sn_5$ layer during reflow at $235^{\circ}C$. The thin layer deposition of an electroless Pd (EP) between the electroless Ni ($7{\mu}m$) and immersion Au ($0.06{\mu}m$) plating on the Cu substrate significantly retarded the massive spalling of the $(Cu,Ni)_6Sn_5$ layer during reflow. Its retarding effect increased with an increasing EP layer thickness. When the EP layer was thin (${\leq}0.1{\mu}m$), the retardation of the massive spalling was attributed to a reduced growth rate of the $(Cu,Ni)_6Sn_5$ layer and thus to a lowered consumption rate of Cu in the bulk solder during reflow. However, when the EP layer was thick (${\geq}0.2{\mu}m$), the initially dissolved Pd atoms in the molten solder resettled as $(Pd,Ni)Sn_4$ precipitates near the solder/$(Cu,Ni)_6Sn_5$ interface with an increasing reflow time. Since the Pd resettlement requires a continuous Ni supply across the $(Cu,Ni)_6Sn_5$ layer from the Ni(P) substrate, it suppressed the formation of $(Ni,Cu)_3Sn_4$ at the $(Cu,Ni)_6Sn_5/Ni(P)$ interface and retarded the massive spalling of the $(Cu,Ni)_6Sn_5$ layer.

• Journal of the Korean institute of surface engineering
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• v.48 no.4
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• pp.149-157
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• 2015

We investigated the effects of the fabric structure or the kinds of plated metals on the electromagnetic interference shielding effectiveness (EMI SE) by means of electroless plating on polyester fabric. We found that the weight of deposited metal, EMI SE, and flexibility of the conductive fabric for EMI shield is affected by morphology of fabric and structure of fiber. The EMI SE of conductive fabric plated Ni/Cu/Ni by electroless plating method on draw textured yarn (DTY) polyester was in the practically useful range of above 70 dB over a wide frequency range of 10 MHz to 1.0 GHz at the surface resistivity of $0.05{\Omega}/{\square}$. Au or Ag plated conductive fabric by immersion plating method is not able to provide for a good EMI SE.

• Journal of Power System Engineering
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• v.5 no.2
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• pp.71-78
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• 2001

Using sodium hypophosphite as reducing agent, bath composition and plating condition of electroless copper plating on plating rate have been studied. The followings were determined as optimum, bath composition; $CuSO_4\;0.025M,\;NiSO_4\;0.002M,\;NaH_2PO_2\;0.4M$, sodium citrate 0.06M, $H_3BO_3$ 0.6M, thiourea or 2-MBT $0.2mg/{\ell}$, and operation conditions; pH $9{\sim}10$ at bath temperature rage of $60{\sim}70^{\circ}C$. A small amount of nickel ion($Ni^{2+}/Cu^{2+}$=0.002/0.025) to the hypophosphite reduced solution promotes autocatalysis and continuous plating. An additive such as thiourea or 2-MBT of a small amount($0.2mg/{\ell}$) can be used to stabilize the solution without changing plating rate much. The attivation energy between $20^{\circ}C\;and\;70^{\circ}C$ were calculated to be 11.3kcal/mol for deposition weight. Plating reaction had been ceased by the adjustment of pH above 13, temperature higher than $90^{\circ}C\;and\;under\;20^{\circ}C$. Deposited surface became worse in the case of increment of bath temperature above $80^{\circ}C$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.878-881
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• 2006

In this paper, the luminance and resistance from different electrode materials of external electrode fluorescent lamp are measured and analyzed. New materials and process technology of external electrode are very important for the developed characteristics in lamp fabrication. In this experiments, three different types for the forming of external electrode are Cu and Al taping, silver paste, Ni and Cu electrode-less plating methods. In the measurements of luminance, the results of brightness by Ni and Au plating methods for the external electrode on lamp glass are presented and also compared with the results by the methods using different electrode materials. The measured resistance values of Ni and Au plating process showed a little bit higher than that of silver paste process in spite of developed results of brightness. But the Ni and Ni/Au plating processes are demonstrated best results and are also showed a little bit different brightness due to different previous sulfate etching treatments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.549-554
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• 2007

In this paper, the luminance and resistance from different electrode materials of external electrode fluorescent lamp are measured and analyzed. New materials and process technology of external electrode are very important for the developed characteristics in lamp fabrication. This experiment, three different types for the forming of external electrode are Cu and Al taping, silver paste, Ni and Cu electrode-less plating methods. In the measurement of luminance, the results of brightness by Ni and Au plating methods for the external electrode on lamp glass are presented and also compared with the results by the methods using different electrode materials. The measured resistance values of Ni and Au plating process showed a little bit higher than that of silver paste process in spite of developed results of brightness. The Ni and Ni/Au plating processes are demonstrated best results and also showed a little bit different brightness due to different previous surface etching treatments.