• Journal of the Korean institute of surface engineering
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• v.26 no.5
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• pp.263-270
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• 1993

The effects of surfactants on electorless copper plating bath for PCB was studied. Basic bath composition was cuplic sulfate 10g/l, EDTA.2Na 40 g/l, formalin$ 3m\ell$/l and sodium hydroxide solution for pH adjust. After addition of accelerators, stabilizers and surfactants, the polarization curves in plating bath were carried out for presumption of the plating rate. From the plating rate in bath with the various concentration of additives, the optimum condition for manufacturing the electroless copper plating bath was confirmed. It was found that the addition of $\alpha$.$\alpha$'-dipyridyl, pyridine and polyxyethylene octylphenylether was good as stabilizer, accelerator and surfactants, respectively. With this additives, the maximum plating rate of $12\mu\textrm{m}$/h at $65^{\circ}C$ and $2\mu\textrm{m}$/h at $25^{\circ}C$ was obtained.

• Journal of the Korean institute of surface engineering
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• v.47 no.6
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• pp.275-281
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• 2014

An ultrasound-assisted Sn-Ag-Pd activation method for electroless copper plating was presented in this study. With this activation process, it was shown that the fine catalyst particles were homogeneously distributed with high density on the entire specimen. In addition, it was observed that incubation period occurred during the electroless plating step was decreased owing to the absorption of Ag which holds high catalytic activity. Resulting from the refinement and high densification of catalyst, the defect-free gap-fill was achieved within the 20x nm trench.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.1
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• pp.41-47
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• 2012

The LDS(Laser Direct Structuring) is one of the new direct writing methods to fabricate conductive patterns by energy beam. It uses thermoplastic polymers with an additive compound that serves as plating seed after the activation by laser. The advantages of LDS include the miniaturization of electrical components, design flexibility, and a reduced number of production steps. The purpose of this study is to investigate the fundamental mechanism for LDS and the characteristics of conductive patterns by laser parameters. These results were studied by SEM, EDX, and XPS analysis. We have used a 20W pulse-modulated fiber laser and copper electroless plating to fabricate conductive patterns on polymer. The result showed that electroless copper plating seed caused the laser cracking of additive compound. In particular, the additive compound contained in copper metal oxides atoms will be changed to copper metal elements. Also, the characteristics of conductive patterns were dependent on laser parameter, especially laser fluence.

• Membrane and Water Treatment
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• v.10 no.3
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• pp.239-244
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• 2019

Plating wastewater containing various heavy metals can be produced by several industries. Specifically, we focused on the removal of copper (Cu2+) and nickel (Ni+) ions from the plating wastewater because all these ions are strictly regulated when discharged into watershed in Korea. The application of both nanofiltration (NF) and reverse osmosis (RO) technologies for the treatment of wastewater containing copper and nickel ions to reduce fresh water consumption and environmental degradation was investigated. In this work, the removal of copper (Cu2+) and nickel (Ni+) ions from synthetic water was studied on pilot scale remove by before using two commercial nanofiltration (NF) and reverse osmosis(RO) spiral-wound membrane modules (NE2521-90 and RE2521-FEN by Toray Chemical). The influence of main operating parameters such as feed concentration on the heavy metals rejection and permeate flux of both membranes, was investigated. Synthetic plating wastewater samples containing copper ($Cu^{2+}$) and nickel ($Ni^{2+}$) ions at various concentrations(1, 20, 100, 400 mg/L) were prepared and subjected to treatment by NF and RO in the pilot plant. The results showed that NF, RO process, with 98% and 99% removal for copper and nickel, respectively, could achieve high removal efficiency of the heavy metals.

• Journal of the Korean institute of surface engineering
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• v.29 no.2
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• pp.140-145
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• 1996

Silver deposits formed on copper substrates by replacement reactions show poor adhesion, and a silver film plated on such a deposit does not adhere. Silver ion makes a highly stable complex with cyanide ion, so that in a silver cyanide solution, the activity of silver ion is very small. This is one of the reasons for the universal use of cyanide baths in the industrial silver plating. However, the consideration of the difference between the values of the stability constants for bath the silver-iodide complex and the copper-iodide complex suggest that the rate of replacement deposition of silver on the copper substrate in si]ver-potassium iodide solution, could be comparatively low. To confirm this, the rate of replacement deposition of silver in both a silver-potassium iodide solution ($AgNO_3$0.10 mol/L, KI 2.00 mol/L ) and a strike silver plating bath (AgCN 0.028 mol/L, KCN 1.15 mol/L ) was estimated from the current density corresponding to the point of intersection of the anodic and the cathodic polarization curves. These estimated values were almost the same, and it is suggested that the silver-potassium iodide solution is not only a cyanide free silver plating bath capable of employing a copper substrate but a silver plating bath which requires no strike plating.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.24-26
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• 2006

The copper foil of 10fm of thickness was prepared, and the surface treatment on the copper foil was done by the method of the electrolytic plating in the acid solution with the sulfate ion as a purpose to remove the main element of the surface contaminant of copper variously. The structure on the surface of the copper foil in this study investigated AFM with SEM the changed phenomenon according to added plating time and current. The phenomenon of the structure's of the oxide on the surface of long plating time and high current growing was confirmed.

• International Journal of Quality Innovation
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• v.2 no.2
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• pp.69-92
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• 2001

The laser-assisted seeding (LAS) process has potential to replace conventional electroless copper plating in Printed Circuit Board (PCB) manufacturing since it combines the steps of laser drilling and plating into one single process. In the LAS process, the single extra LAS step can metallize a microvia. Thus, the process steps can be greatly reduced and the productivity enhanced, but also the high aspect ratio microvias can be metallized. The objectives of this paper are to study the LAS copper thickness within PCB microvias and the thermal reliability of the microvias produced by this process. It was found that results were satisfactory in both the reliability test and also the LAS copper thickness which both comply with IPC standard, the copper thickness produced by the LAS process is sufficient for subsequent electro-plating process. The reliability of the microvias produced by LAS process is acceptable which are free from any voids, corner cracks, and distortion in the plated copper.

• Korean Journal of Materials Research
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• v.11 no.10
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• pp.820-832
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• 2001

In order to obtain the basic data on the optimum conditions of electroforming process for fabricating the micro wiring pattern for plate type micro- motor core, characteristics of plating bath and properties of deposits were studied with various copper plating baths which contain sulfate, fluoborate, pyrophosphate and cyanide salt, respectively. Cathodic polarization, throwing power, internal stress, texture and surface morphology of deposits were observed. Throwing power of plating solution is deeply related to the polarization curves and the values are in the range of +20∼20%. The order of values ate as follows- pyrophosphate, cyanide, sulfate and fluoborate bath. Internal stresses of deposits are tensile in all of the copper plating bath. Thickness of the deposits plated at the center of holes has the highest value in the pyrophosphate bath and K factor, ratio of height and width of deposit, is 1.44. It was confirmed that the pyrophosphate bath was the best one for the electroforming of wire pattern.

• Journal of the Korean institute of surface engineering
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• v.51 no.4
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• pp.191-196
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• 2018

The self-annealing which leads evolution of microstructure in copper electroplating layers at room temperature occurs after forming deposition layer. During the process, crystal orientation, size and sheet resistance of plating layer change. Lastly, it causes the change of physical and mechanical characteristics such as a tensile strength of plating layer. In this study, the variation of incorporated impurities, microstructure and sheet resistance of copper plating layer formed by electroplating are measured with and without inorganic additives during the self-annealing. In case of absence of inorganic additives, the copper layer presents strong total intensity of incorporated impurities. During the self-annealing, such width of reduction was significant. Moreover, microstructure and crystal size are increased while the tensile strength is decreased noticeably. On the other hand, in the presence of inorganic additives, there is no observable distinction in the copper plating layer. According to the observation on movements of the incorporated impurities in electrodeposition copper layer, within 12 hours the impurities are continuously shifted from inside of the plating layer to its surface after as-deposited electroplating. Within 24 hours, except for the small portion of surface layer, it is considered that most of the microstructure is transformed.

• Journal of the Korean institute of surface engineering
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• v.49 no.3
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• pp.265-273
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• 2016

The effects of surface modification by nitric acid on the pre-treatment of electroless copper plating were investigated. Copper was electroless-plated on the nitric acid treated graphite activated by a two-step pre-treatment process (sensitization + activation). The chemical state and relative quantities of the various surface species were determined by X-ray photoelectron spectroscopy (XPS) after nitric acid modification or pre-treatment. The acid treatment increased the surface roughness of the graphite due to deep and fine pores and introduced the oxygen-containing functional groups (-COOH and O-C=O) on the surface of graphite. In the pre-treatment step, the high roughness and many functional groups on the nitric acid treated graphite promoted the adsorption of Sn and Pd ions, leading to the uniform adsorption of catalyst ($Pd^0$) for Cu deposition. In the early stage of electroless plating, a lot of tiny copper particles were formed on the whole surface of acid treated graphite and then homogeneous copper film with low variation in thickness was formed after 30 min.