• Restorative Dentistry and Endodontics
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• v.14 no.1
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• pp.199-204
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• 1989

The purpose of this study was to observe the anodic polarization curve from 4 kinds of low copper amalgam (Fine cut alloy, Spheralloy, Aristalloy and Amalcap) and 4 kinds of high copper amalgam (Dispersalloy, Sybraloy Orosphere and Tytin) obtained by using the potentiostat. The specimen made as the direction of manufacturer was stored at room temperature for about 7 days. The standard surface preparation was routinely carried out. The 0.9% saline solution was used as electrolyte in pH 6.8-7.0 at $37^{\circ}C$. The open circuit potential was determined after 30 minutes' immersion of specimen. The scan rate was 1mV/sec and the surface area of amalgam exposed to the solution was 0.785$cm^2$ for each specimen. All potentials reported are with respect to Ag/AgCl eelctrode. The following results were obtained. 1. The corrosion potential of high copper amalgams was higher than one of low copper amalgams, and the current density of high copper amalgam was lower than one of low copper amalgams. 2. The low copper amalgams had the similar pattern of polarization curve, but the high copper amalgams had the different pattern one another. 3. The polarization curve of Orosphere amalgam which is the admixed type was similar to one of low copper amalgam.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1080-1083
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• 2002

In this paper, we have studied with regard to the use of lasers for modifying the surface properties of silicon in order to improve it's wettability and adhesion characteristics. Using an Nd:YAG pulse laser, the wettability and adhesion characteristics of silicon surface have been developed by an Nd:YAG pulse laser. It was found that the laser treatment of silicon surfaces modified the surface energy. In the result of wetting experiments, by the sessile drop technique using the distilled water, wetting characteristic of silicon after the laser irradiation shows a decreased value of the contact angle. In case of the laser treated silicon surface, laser direct writing of copper lines has been achieved by pyrolytic decomposition of copper formate films$(Cu(HCOO)_2{\cdot}4H_2Q)$, using a focused $Ar^+$ laser beam$(\lambda=514.5nm)$ on the silicon substrates. The deposited patterns were measured by energy dispersive X-ray(EDX), Scanning Electron Microscopy(SEM) and surface profiler($\alpha$-step) to examine the cross section of deposited copper lines and linewidth.

• Environmental Engineering Research
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• v.20 no.2
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• pp.199-204
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• 2015

In this study, a novel phosphorus removal filter made of brass scrubber with higher porosity of over 96% was fabricated and evaluated. The brass scrubber was surface-modified to form copper hydroxide on the surface of the brass, which could be a phosphate removal filter for advanced wastewater treatment because the phosphates could be removed by the ion exchange with hydroxyl ions of copper hydroxide. The evaluation of phosphate removal was performed under the conditions of the batch type in wastewater and continuous type through filters. Filter recycling was also evaluated with retreatment of the surface modification process. The phosphate was rapidly removed within a very shorter contact time by the surface-modified brass scrubber filter, and the phosphate mass of 1.57 mg was removed per gram of the filter. The possibility of this surface-modified brass scrubber filter for phosphorus removal was shown without undesirable sludge production of existing chemical phosphorus removal techniques, and we feel that it would be very meaningful as a new wastewater treatment.

• Journal of the Korean institute of surface engineering
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• v.47 no.4
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• pp.162-167
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• 2014

The primary purpose of this research is to investigate how much the complexing agent in electroless Cu electrolytes will affect adhesion strength between copper film and Ta diffusion barrier for Cu interconnect of semiconductor. The adhesion strength using rochelle's salt as complexing agent was higher than the case of using EDTA-4Na. Effect of complexing agent on adhesion strength and electrical resistivity was studied in crystal structural point of view.

• Journal of the Korean institute of surface engineering
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• v.39 no.5
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• pp.215-222
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• 2006

The passivity behavior of copper anode containing impurities in copper sulfate solution for electrorefining process was studied at several different levels of impurities such as As, Sb, Bi and Pb. The passivity behavior was investigated by electrochemical techniques (galvanostatic, potentiodynamic and cyclic voltammetry tests) and surface analysis (optical microscopy, electron probe microanalysis, scanning electron microscopy). The results were that arsenic, antimony inhibited passivation and bismuth accelerated it and lead containing anode showed different passivity behavior from above anodes. The improved passivity characteristics could be explained by decrease in oxygen content in passivity film which resulted from a reaction among the impurities, oxygen and copper in the anode. The SEM image revealed that arsenic or antimony containing anode exhibited a porous passivity film and bismuth containing anode showed the compact passivity film and lead containing anode had loose passivity film on anode.

• Journal of the Korea Convergence Society
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• v.7 no.6
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• pp.193-198
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• 2016

The texture of electrodeposits varies with deposition conditions. Texture of electrodeposits is also related to microstructure, surface morphology and mechanical properties. When the electrodeposits annealed, the recrystallization texture may be different from the original deposition texture. The surface morphology, the microstructure and the initial and recrystallization textures of copper electrodeposits vary with deposition conditions. The texture, microstructure, surface morphology and mechanical properties of electrodeposits are known to vary with electrolysis conditions, such as bath composition, over potential, pH, current density, bath temperature, etc. The (111) and (110) textures of copper electrodeposits can be obtained from copper sulfate bath. In this study, copper electrodeposits with (111) and (110) textures are obtained from a copper sulfate bath, and the change from (111) to (110) textures of copper electrodeposits can be explained.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.3
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• pp.51-57
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• 2019

To protect the Cu surface from oxidation in air, a two-step plasma process using Ar and $N_2$ gases was studied to form a copper nitride passivation as an anti-oxidant layer. The Ar plasma removes contaminants on the Cu surface and it activates the surface to facilitate the reaction of copper and nitrogen atoms in the next $N_2$ plasma process. This study investigated the effect of Ar plasma on the formation of copper nitride passivation on Cu surface during the two-step plasma process through the full factorial design of experiment (DOE) method. According to XPS analysis, when using low RF power and pressure in the Ar plasma process, the peak area of copper oxides decreased while the peak area of copper nitrides increased. The main effect of copper nitride formation in Ar plasma process was RF power, and there was little interaction between plasma process parameters.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.5
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• pp.616-621
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• 2010

New type of the base material of the light-emitting diode requires copper wafer in view of heat and electrical conductance. Therefore, polishing process of the substrate level is needed to get a nanometer level of surface roughness as compared with pattern structure of nano-size in the semiconductor industry. In this paper, a series of lapping and polishing technique is shown for the rough and deflected copper substrate of thickness 3mm. Lapping by sand papers tried air cooling method. And two steps of polishing used the diamond abrasives and the $Al_2O_3$ slurry of size 100mm considering the residual scratch. White-light interferometer proved successfully a mirror-like surface roughness of Ra 6nm on the area of $0.56mm{\times}0.42mm$.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.8
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• pp.334-340
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• 2006

Copper is widely used in electric wire, cable, conductor in electric devices. As the demand for electric power is increasing rapidly, electric power devices are getting amazingly bigger and complicated. The using of light-weight conductor can reduce the size and making cost of the electric devices. In high-frequency application, Electric current in a conductor tends to shift to the surface of the conductor, resulting in an uneven current distribution in the inner conductor. In the extreme case the current may essentially concentrate in the 'skin' of the inner conductor as a surface current. In high frequency application, therefore, inner area of copper conductor may replace with aluminum conductor, which reduces the weight of conductor. This paper describes the manufacture and evaluation of composite conductors made of copper and aluminum. The optimum extruding ratio was 16 at $300^{\circ}C$. The electrical resistance of manufactured composite bus bar was $57{\mu}{\Omega}$ at DC and $49.5{\mu}\{Omega}$ at 300Hz.

• Journal of the Korean institute of surface engineering
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• v.25 no.4
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• pp.173-180
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• 1992

The effects of the stabilizing additives such as NaCN, 2-MBT and Thiourea on bath decom-position, plating rate and surface morphology have been studied. Bath stability was increased in the order of an additive-free bath, and NaCN-, 2-MBT-, and Thiourea-stabilized baths. The sta-bilizing effects may be attributed to the stability of Cu(II) -complexes. The plating rate is the re-verse order of the bath stability. Accelerative effect of 2-MBT in proper quantity(0.3mg/$\ell$) may be explained by visualizing it absorbed through benzene ring or sulfur atom on portions of the sub-strates. The strong bond of the complexing part of the molecule to nearby chelated copper ions would tend to accelerate plating by making it easier for the Cu2+ -ligand bond to be broken. Sur-face morphologies of copper deposits depend on the bath additives. Electroless copper deposits from the 2-MBT stabilized baths are finer than the deposits from the NaCN- and Thiourea- stabi-lized baths due to the strong adsorption on the substrates.