We investigated the effects of DMAB (Borane dimethylamine complex, C2H10BN) in electroless Ni-B film with addition of DMAB as reducing agent for electroless Ni plating. The electroless Ni-B films were formed by electroless plating of near neutral pH (pH 6.5 and pH 7) at 50˚C. The electroless plated Ni-B films were coated on screen printed Ag pattern/PET (polyethylene terephthalate). According to the increase of DMAB (from 0 to 1 mole), the deposition rate and the grain size of electroless Ni-B film increased and the boron (B) content also increased. In crystallinity of electroless Ni-B films, an amorphization reaction was enhanced in the formation of Ni-B film with an increasing content of DMAB; the Ni-B film with< 1 B at.% had a weak fcc structure with a nano crystalline size, and the Ni-B films with > 5 B at.% had an amorphous structure. In addition, the Ni-B film was selectively grown on the printed Ag paste layer without damage to the PET surface. From this result, we concluded that formation of electroless Ni-B film is possible by a neutral process (~green process) at a low temperature of 50˚C.

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 CuSO4·5H2O as the main metal source, NaH2PO2·H2O as the reducing agent, C6H5Na3O7·2H2O and NH4Cl as the complex agents, and NiSO4·6H2O as the catalyser for the oxidation of the reducing agent, dissolved in deionized water. The pH of the Cu plating solutions was adjusted using NH4OH. 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˚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.

The current study examined Ag migration from the Ag paste bump in the SABiT technology-applied PCB. A series of experiments were performed to measure the existence/non-existence of Ag in the insulating prepreg region. The average grain size of Ag paste was 30 nm according to X-ray diffraction (XRD) measurement. Conventional XRD showed limitations in finding a small amount of Ag in the prepreg region. The surface morphology and cross section view in the Cu line-Ag paste bump-Cu line structure were observed using a field emission scanning electron microscope (FE-SEM). The amount of Ag as a function of distance from the edge of Ag paste bump was obtained by FE-SEM with energy dispersive spectroscopy (EDS). We used an electron probe micro analyzer (EPMA) to improve the detecting resolution of Ag content and achieved the Ag distribution function as a function of the distance from the edge of the Ag paste bump. The same method with EPMA was applied for Cu filled via instead of Ag paste bump. We compared the distribution function of Ag and Cu, obtained from EPMA, and concluded that there was no considerable Ag migration effect for the SABiT technology-applied printed circuit board (PCB).

According to progress rapidly digitalization, networked and mobilization of electronics industry, there are demands for being smaller, thinner, more light, and more efficient complex functions of electronic devices which are wireless devices, semi-conductors, packages and mobile devices. Therefore, the solder resist on a printed circuit board have been required with the high resolution and the eco-friendly materials in the surface treatments such as high heating process and coating process with electrolysis. In this study, the photoinitiator initiator and monomers of the solder resist were prepared with their contents for reducing the occurrence of the under-cut. We investigated the sample surface by UV/VIS spectrometer, FT-IR, OM after HASL and ENIG process. From our results, it is possible to get a high adhesion of resist with optimal contents between the photoinitiator initiator and monomers after surface treatments.

무전해 PCB 도금 공정 수세액을 분리막으로 처리하여 투과수는 공업용수로 재사용하고 유가금속인 금(Au)을 회수하는 방법에 관하여 연구하였다. 역삼투 분리막 테스트 셀을 이용하여 수세액 처리에 적합한 분리막을 선정하였으며 scale-up을 위한 나권형 모듈 투과 실험을 실시하였다. 먼저, (주)새한에서 생산되는 RO-TL(tap water, low pressure), RO-BL(brackish water, low pressure), RO-normal(for water purifier)막으로 투과실험하였으며 그 중 RO-TL막이 soft etching, 촉매 및 Ni 수세액 처리에 우수한 것으로 판명되었다. 따라서 RO-TL막으로 제작한 나권형 가정용 정수기 모듈로 7bar, 25℃에서 scale-up 실험을 수행하였다. Au수세액의 투과 유속은 약 30 LMH로서 가장 높았으나 Au 제거율이 80% 미만이었다. Pd, Ni 및 soft etching 수세액의 투과유속은 각각 약 22, 17, 10 LMH 정도이며 Pd의 제거율은 85% 이상, Ni 및 Cu 제거율은 97% 이상이었다. 또한 Au, Ni 및 Cu 이온이 함유된 수세액 중 유가금속인 Au를 선택적으로 회수하기 위하여 NF막을 사용하였다. Au수세액 중 Ni 및 Cu 이온은 대부분 제거되었으며 투과액 중에 Au이온이 81.9% 존재하였고 계속하여 RO-TL막으로 Au를 농축 회수하였다. 마지막으로 4"직경의 NF 및 RO-TL 나권형 모듈을 연속적으로 사용하여 Au를 효과적으로 회수할 수 있음을 재확인하였다.인하였다.

This paper attempted to elucidate pyrolysis reaction characteristics of waste paper laminated phenolic-printed circuit board (p-PCB). Thermogravimetric analysis was performed for the pyrolysis kinetic analysis of waste p-PCB and Pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS) was also employed to analyze the product distribution of waste p-PCB pyrolysis reaction under isothermal condition (230, 350, 600oC). Kinetic analysis and isothermal Py-GC/MS results showed that the pyrolysis reaction of waste p-PCB has three reaction temperature regions: 1) low temperature decomposition region (< 280oC), 2) medium temperature decomposition region (280 ~ 380oC), 3) high temperature decomposition region (> 380oC). At the first region, triphenyl phosphate used as fire retardant, water, and phenol were vaporized. At the second region, phenolic resin, tetrabromobisphenol-A (TBBA), and laminated paper are decomposed and produce phenols, brominated compounds, and levoglucosan which were the specific pyrolysis reaction products of phenolic resin, TBBA, and laminated paper, respectively. In the final region, cresol and alkyl benzene were detected which can be considered as the decomposition products of phenolic resin. By above results, pyrolysis reaction pathway of waste p-PCB is accounted for a series reaction with four independent reactions of phosphate based frame retardant, TBBA, laminated paper, and phenolic resin.

Through industrial developing, electronic waste is occurred by short lifespan of electronic products. This study discusses an approach of the eco-efficiency for waste PCB (Printed Circuit Board) recycling process through environment and economic analysis. The recycling of waste PCB 1 kg has 1.89E + 00kg CO2 eq. of global warming potential and 2.84E −02 kg antimony eq. of abiotic resource depletion. In terms of economy, this process costs 6,601.91 KRW per 1kg waste PCB recycling. Use of economic and environmental result, when compare with same amounts of virgin metal, environmental-efficiency of GWP (Global Warming Potential) is at 4.16E + 00 and ARD(Abiotic Resource Depletion) is at 2.91E + 00. And compare with secondary metal, environmental-efficiency of GWP is at 2.11E + 00 and ARD is at 8.49E − 01. In addition economic-efficiency is at 1.19E + 00. The results of optimization of this process will be increased. This study will show the process economical and environmental decision making

This research was designed to elucidate the pyrolysis reaction characteristics of waste epoxy printed circuit board (e- PCB). The samples were pulverized after removing coppers by gravity separator. Non-isothermal pyrolysis kinetic results by Thermogravimetric Analyzer (TGA) displayed two apparent reaction regions : 1) fast degradation zone and 2) slow degradation zone. According to batch experiments, solid by-products are responsible for about 78%, while liquid and gas by-products, respectively, represent 13 and 9%. The high content of solid by-products is ascribed to that of SiO2 that is a major components of e-PCB. Liquid by-products exhibit high content of oxygen (19%) and contain the nitrogen of about 1%. It is recommended that gas, liquid, and solid by-products of waste e-PCB would not be applied directly as fuels. Instead, pyrolysis of e-PCB would be applied to recover valuable rare metals and coppers from solid by-products. Application of liquid by-products is likely to be limited due to the presence of brominated oils precursor in liquid byproducts. It is necessary to develop upgrading methods for improving the quality of liquid by-products of waste e-PCB. According to kinetic analysis and product characterization, pyrolysis reaction model of waste e-PCB is accounted for by a series reaction with two independent reactions of two resins: brominated epoxy resins and non-brominated epoxy resins. At the first-stage, two resins are independently decomposed to generate thermally stable intermediates followed by slow degradation of the intermediates to be converted into char.