• 대한금속재료학회지
• /
• 제48권1호
• /
• pp.90-100
• /
• 2010

Micro-conductive patterns were microfabricated on an insulating substrate ($SiO_2$) surface by a selective electroless nickel plating process in order to investigate the formation of seed layers. To fabricate micro-conductive patterns, a thin layer of metal (Cu.Cr) was deposited in the desired micropattern using laser-induced forward transfer (LIFT). and above this layer, a second layer was plated by selective electroless plating. The LIFT process. which was carried out in multi-scan mode, was used to fabricate micro-conductive patterns via electroless nickel plating. This method helps to improve the deposition process for forming seed patterns on the insulating substrate surface and the electrical conductivity of the resulting patterns. This study analyzes the effect of seed pattern formation by LIFT and key parameters in electroless nickel plating during micro-conductive pattern fabrication. The effects of the process variables on the cross-sectional shape and surface quality of the deposited patterns are examined using field emission scanning electron microscopy (FE-SEM) and an optical microscope.

• 마이크로전자및패키징학회지
• /
• 제15권2호
• /
• pp.17-21
• /
• 2008

Sn-Cu계 솔더 범프에서 무전해도금법을 이용한 범프 형성에 대한 연구를 하였다. $20{\mu}m$ via에 전기도금법으로 구리를 채운 웨이퍼 위에 ball형태의 범프를 형성하기 위하여 구리와 주석을 도금하여 약 $10{\mu}m$높이의 범프를 형성하였다. 구리 범프 형성 시 via위에 선택적으로 도금하기 위하여 활성화 처리 후 산세처리를 실시하고 무전해 도금액에 안정제를 첨가하였다. 무전해도금법을 이용하여 주석 범프 형성 시 도금층이 구리 범프에 비해 표면의 균일도가 벌어지는 것으로 관찰되었지만 reflow공정을 실시한 후 ball 형태의 균일한 Sn-Cu 범프를 형성하였다.

• 한국표면공학회지
• /
• 제48권4호
• /
• pp.149-157
• /
• 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.

• 자원리싸이클링
• /
• 제21권2호
• /
• pp.41-46
• /
• 2012

전해채취법을 이용하여 무전해 니켈 도금폐액으로부터 니켈을 회수하기 위한 실험을 수행하였다. 이를 위해 우선 가성소다를 첨가하는 방법으로 무전해 니켈 도금폐액중의 니켈을 수산화물 형태로 침전분리하였다. 또한, 니켈 수산화물을 황산 용액으로 용해시킨 니켈 수용액을 대상으로 전기분해를 실시하였다. 실험결과, 가성소다를 첨가하여 pH 10 이상으로 조절하면 99% 이상의 Ni을 수산화물로 침전시킬 수 있는 것으로 나타났다. 한편, 니켈 수용액으로부터 전해채취를 통한 Ni의 석출시 전류밀도가 증가할수록 전류효율은 감소하는 것으로 나타났다.

• Corrosion Science and Technology
• /
• 제21권2호
• /
• pp.89-99
• /
• 2022

A versatile method for performing non-cyanide electroless gold plating using thiomalic acid (TMA) as a complexing agent and 2-aminoethanethiol (AET) as a reducing agent was investigated. It was found that TMA was an excellent complexing agent for gold. It can be used in electroless gold plating baths at a neutral pH with a high solution stability, makes it a potential candidate to replace conventional toxic cyanide complex. It was found that one gold atomic ion could bind to two TMA molecules to form the [2TMA-Au⁺] complex in a solution. AET can be used as a reducing agent in electroless gold plating solutions. The highest current density was obtained at electrode rotation rate of 250 to 500 rpm based on anodic and cathodic polarization curves with the mixed potential theory. Increasing AET concentration, pH, and temperature significantly increased the anodic polarization current density and shifted the plating potential toward a more negative value. The optimal gold ion concentration to obtain the highest current density was 0.01 M. The cathodic current was higher at a lower pH and a higher temperature. The current density was inversely proportional to TMA concentration.

• 한국표면공학회지
• /
• 제29권6호
• /
• pp.709-713
• /
• 1996

Mechanical solderless chip packaging with small gold bumps or metal balls has increased in the electronic devices. The preparation of conductive particles (5~7 $\mu\textrm{m}$ diamiter) by electroless nickel plating have been investigated. Generally, batch type electroless plating is applied to provide conductivity on the nonconductors. Since the surface areas of particles are much larger than the bulk substrate, accordingly the electroless plating bath becomes unstable. Thus, we applied the continuous dropping method for the preparation of conductive particles. The uniform coverage of deposited nickel on the particles was obtained by using ammonium acetate as a complexing agent, and surface coverage is further improved without coagulation of particles by the surface active agent treatment before enter the plating bath.

• 전기화학회지
• /
• 제3권4호
• /
• pp.196-199
• /
• 2000

무전해 도금은 내식성, 내구성, 전도성 특별히 비전도성 물질의 도금이 요구되는 모든 재료에 폭 넓게 사용되는 우수한 표면 처리 방법이다. 무전해 니켈 도금은 비자성, 무정형 구조,내구성, 내식성 그리고 열정 안정성 등의 많은 장점을 갖는다. 본 연구에서는 무전해 니켈 도금의 열처리에 따른 무전해 니켈-인 도금의 경도와 내식성의 변화를 연구하였다. 가장 높은 경도 값은 $500^{\circ}C$열처리에서 얻어졌다. $300^{\circ}C$에서 열처리한 도금의 내식성이 60시간 동안 1몰의 황산 수용액에서 테스트 한 결과 가장 우수하였다.

• 한국재료학회지
• /
• 제23권11호
• /
• pp.661-665
• /
• 2013

We investigated the characteristics of electroless plated Cu films on screen printed Ag/Anodized Al substrate. Cu plating was attempted using neutral electroless plating processes to minimize damage of the anodized Al substrate; this method used sodium hypophosphite instead of formaldehyde as a reducing agent. The basic electroless solution consisted of $CuSO_4{\cdot}5H_2O$ as the main metal source, $NaH_2PO_2{\cdot}H_2O$ as the reducing agent, $C_6H_5Na_3O_7{\cdot}2H_2O$ and $NH_4Cl$ as the complex agents, and $NiSO_4{\cdot}6H_2O$ as the catalyser for the oxidation of the reducing agent, dissolved in deionized water. The pH of the Cu plating solutions was adjusted using $NH_4OH$. According to the variation of pH in the range of 6.5~8, the electroless plated Cu films were coated on screen printed Ag pattern/anodized Al/Al at $70^{\circ}C$. We investigated the surface morphology change of the Cu films using FE-SEM (Field Emission Scanning Electron Microscopy). The chemical composition of the Cu film was determined using XPS (X-ray Photoelectron Spectroscopy). The crystal structures of the Cu films were investigated using XRD (X-ray Diffraction). Using electroless plating at pH 7, the structures of the plated Cu-rich films were typical fcc-Cu; however, a slight Ni component was co-deposited. Finally, we found that the formation of Cu film plated selectively on PCB without any lithography is possible using a neutral electroless plating process.

• 전기화학회지
• /
• 제2권3호
• /
• pp.138-143
• /
• 1999

최근 large scale integrated circuits(LSI) 및 printed circuit board(PCB)의 세밀화가 전자기기의 소형화로 인하여 필수 불가결하게 되었다. 전해 도금은 LSI및 PCB의 전도도 및 부식저항을 향상시키기 위해서 전도성 라인의 말단에 적용되고 있다. 그러나 회로 기판의 소형화 및 고직접화로 인하여 적용되지 못하고 있다. 따라서 최근 무전해 도금은 복잡한 장치와 외부에서 전원을 필요치 않는 작동의 간편함 때문에 매우 각광 받고 있는 방법 중의 하나이다. 본 연구는 무전해 니켈/금도금의 도금 기술 개발을 위해 시험하였다. 무전해 니켈 도금은 $85^{\circ}C$의 도금 욕에서 PCB기판 위에 침적 시켰고 그 다음 금층은 동일한 방법으로 $90^{\circ}C$에서 니켈 층위에 침적 시켰다. Bonderbility는 무전해 니켈/금도금의 안정성을 평가하기 위해 gold wire 또는 solder ball 테스트로 실험하였다.

• 한국재료학회지
• /
• 제27권8호
• /
• pp.409-415
• /
• 2017

For enhanced cavitation erosion resistance of vessel propellers, an electroless Ni-P plating method was introduced to form a coating layer with high hardness on the surface of Cu alloy (CAC703C) used as vessel propeller material. An electroless Ni-P plating reaction generated by Fe atoms in the Cu alloy occurred, forming a uniform amorphous layer with P content of ~10 wt%. The amorphous layer transformed to (Ni3P+Ni) two phase structure after heat treatment. Cavitation erosion tests following the ASTM G-32 standard were carried out to relate the microstructural changes by heat treatment and the cavitation erosion resistance in distilled water and 3.5 wt% NaCl solutions. It was possible to obtain excellent cavitation erosion resistance through careful microstructural control of the coating layer, demonstrating that this electroless Ni-P plating process is a viable coating process for the enhancement of the cavitation erosion resistance of vessel propellers.