• Journal of the Korean Chemical Society
• /
• v.47 no.6
• /
• pp.608-613
• /
• 2003

In order to remove particles on surface of post-oxide CMP wafer, new cleaning solution was prepared by mixing with DHF (Diluted HF), nonionic surfactant PAAE (Polyoxyethylene Alkyl Aryl Ether), DMSO (Dimethylsulfoxide) and D.I.W.. Silicone wafers were intentionally contaminated by silica, alumina and PSL (polystylene latex) which had different zeta potentials in cleaning solution. This cleaning solution under megasonic irradiation could remove particles and metals simultaneously at room temperature in contrast to traditional AMP (mixture of $NH_4OH,\;H_2O_2$ and D.I.W) without any side effects such as increasing of microroughness, metal line corrosion and deposition of organic contaminants. This suggests that this cleaning solution would be useful future application with copper CMP in brush cleaning process as well as traditional post CMP cleaning process.

• Resources Recycling
• /
• v.21 no.1
• /
• pp.75-81
• /
• 2012

Porous pellets for immobilizing heavy metals were manufactured from coal tailings and iron oxide powder. Coal tailings was pulverized and mixed with iron oxide powder. The mixed powder was granulated into spherical pellets and roasted. Over $1100^{\circ}C$, residual coal in coal tailings reduced iron oxide to ZVI(Zero-Valent Iron). The pellets have 34.63% of porosity, 1.31 g/mL of bulk density, and 9.82.urn median pore diameter. The pellets were reacted with synthetic solutions containing each heavy metals: arsenic(V), copper(II), chrome(VI), and cadmium(II), respectively. On the test of immobilizing heavy metal, the pellets made at $1100^{\circ}C$ were superior to the other pellets made under $1000^{\circ}C$. Immobilizing over 99.9% of 10ppm heavy metal solutions required I hour for arsenic, 2 hours for chrome, and 4 hours for copper. However, immobilizing capacity of cadmium was inferior to that of the other metals and it was decreased in reversely proportion to initial concentration of the solutions.

• Journal of Preventive Medicine and Public Health
• /
• v.31 no.3 s.62
• /
• pp.414-423
• /
• 1998

Metal fume fever has been known as an occupational disease is induced by intense inhalation of fresh metal fume with a particle size smaller than $0.5{\mu}m\;to\;1{\mu}m$. The fumes originate from heating metals beyond their boiling point, as happens, for example, in welding operations. Oxidation usually accompanies this process. In most cases, this syndrome is due to exposure to zinc oxide fumes; however, other metals like copper, magnesium, cadmium, manganese, and antimony are also reported to produce such reactions. Authors report a case of metal fume fever suspected to be associated with copper fume inhalation. The patient was a 42-year-old male and was a smoker. He conducted inert gas tungsten arc welding on copper-coated materials without safety precautions such as a protective mask and adequate ventilation. Immediately after work, he felt metallic taste in his mouth. A few hours after welding, he developed headache, chilling sensation, and chest discomfort. He also complained of myalgia, arthralgia, feverish sensation, thirst, and general weakness. Symptoms worsened after repeated copper welding on the next day and subsided gradually following two weeks. Laboratory examination showed a transient increase of neutrophil count, eosinophilia, elevated erythrocyte sedimentation rate, and positive C-reactive proteinemia. Blood and urine copper level was also increased compared to his wife. Before this episode, he experienced above complaints several times after welding with copper materials but welding of other metals did not produce any symptoms. It was suggested that copper fume would have induced metal fume fever in this case. Further investigations are needed to clarify their pathogenic mechanisms.

• Korean Journal of Materials Research
• /
• v.26 no.3
• /
• pp.130-135
• /
• 2016

To alloy high melting point elements such as boron, ruthenium, and iridium with copper, heat treatment was performed using metal oxides of $B_2O_3$, $RuO_2$, and $IrO_2$ at the temperature of $1200^{\circ}C$ in vacuum for 30 minutes. The microstructure analysis of the alloyed sample was confirmed using an optical microscope and FE-SEM. Hardness and trace element analyses were performed using Vickers hardness and WD-XRF, respectively. Diffusion profile analysis was performed using D-SIMS. From the microstructure analysis results, crystal grains were found to have formed with sizes of 2.97 mm. For the copper alloys formed using metal oxides of $B_2O_3$, $RuO_2$, and $IrO_2$ the sizes of the crystal grains were 1.24, 1.77, and 2.23 mm, respectively, while these sizes were smaller than pure copper. From the Vickers hardness results, the hardness of the Ir-copper alloy was found to have increased by a maximum of 2.2 times compared to pure copper. From the trace element analysis, the copper alloy was fabricated with the expected composition. From the diffusion profile analysis results, it can be seen that 0.059 wt%, 0.030 wt%, and 0.114 wt% of B, Ru, and Ir, respectively, were alloyed in the copper, and it led to change the hardness. Therefore, we verified that alloying of high melting point elements is possible at the low temperature of $1200^{\circ}C$.

• Korean Journal of Materials Research
• /
• v.11 no.6
• /
• pp.527-532
• /
• 2001

Dry etching of copper film using $O_2$ plasma and H(hfac) has been investigated. A one-step process consisting of copper film oxidation with an $O_2$ plasma and the removal of surface copper oxide by the reaction with H(hfac) to form volatile Cu(hfac)$_2$ and $H_2O$ was carried but. The etching rate of Cu in the range from 50 to 700 /min was obtained depending on the substrate temperature, the H(hfac)/O$_2$ flow rate ratio, and the plasma power. The copper film etch rate increased with increasing RF power at the temperatures higher than 215$^{\circ}C$. The optimum H(hfac)/O$_2$ flow rate ratio was 1:1, suggesting that the oxidation process and the reaction with H(hfac) should be in balance. Cu patterning using a Ti mask was performed at a flow rate ratio of 1:1 on 25$0^{\circ}C$\ulcorner and an isotropic etching profile with a taper slope of 30$^{\circ}$was obtained. Cu dry patterning with a tapered angle which is necessary for the advanced high resolution large area thin film transistor liquid-crystal displays was thus successfully obtained from one step process by manipulating the substrate temperature, RF power, and flow rate ratio.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.11
• /
• pp.3227-3232
• /
• 2013

A novel Cu-Co-O composite nanocatalyst was designed and prepared for the ozonation of phenol. A synergistic effect of copper and cobalt was observed over the Cu-Co-O composite nanocatalyst, which showed higher activity than either copper or cobalt oxide alone. In addition, the Cu-Co-O composite revealed good activity in a wide initial pH range (4.11-8.05) of water. The fine dispersion of cobalt on the surface of copper oxide boosted the interaction between catalyst and ozone, and the surface Lewis acid sites on the Cu-Co-O composite were determined as the active sites. The Raman spectroscopy also proved that the Cu-Co-O composite was quite sensitive to the ozone. The trivalent cobalt in the Cu-Co-O composite was proposed as the valid state.

• Advances in nano research
• /
• v.16 no.5
• /
• pp.501-508
• /
• 2024

In this study, nanotoxicity tests were made by exposure of Artemia salina to copper (Cu 60-80 nm) and copper oxide (CuO 40 nm) nanoparticles (NPs) at different concentrations (0.2, 1, 5, 10, 25, and 50 mg/L). The LC₅₀ value of Cu (60-80 nm) NPs on the A. salina individuals at the beginning (0), 24^th, 48^th and 72^nd hours and elimination period was 52.37 mg/L while the LC₅₀ value of CuO (40 nm) NPs was 55.39 mg/L. The results of UV-Vis absorbance values showed that all statistical data revealed that maximum effect was observed between 24-30 hours and 25 ppm absorbance concentration was more effective. The multiple R, correlation coefficient (R2) and adjusted R2 values of Cu NP for the suitable Quadratic model were, respectively; 92.96 %, 86.42 % and 76.71 % while they are 98.31 %, 96.64 % and 94.25 % for CuO NP. Also, the data, was indicated effect size significantly changed based on the type and size of NP. Considering the microscope results, it was clearly noticed that A. salina organisms took the NPs in to their body. The accumulation in the gut of A. salina was observed and the images were taken with phase contrast microscope for both of NPs. The highest decrease for survival rates of A. salina individuals exposed to Cu NP was observed in the 10 ppm concentration (43.47 %) and in the 5 ppm concentration (46.20 %) for CuO NP. The results revealed that Cu and CuO NPS showed different toxic effects and that Cu NPs were more toxic than CuO.

• Journal of the Korean institute of surface engineering
• /
• v.32 no.4
• /
• pp.531-537
• /
• 1999

A copper based leadframe was oxidized in brown-oxide forming solution, then the growth characteristics of brown oxide and the effect of brown-oxide formation on the adhesion strength of leadframe to epoxy molding compound (EMC) were studied by using sandwiched double cantilever beam (SDCB) specimens. The brown oxide is composed of fine acicular CuO, and its thickness increased up to ~150 nm within 2 minutes and saturated. Bare leadframe showed alomost no adhesion to EMC, while once the brown-oxide layer formed on the Surface of leadframe, the adhesion strength increased up to ~80 J/$\m^2$ within 2 minutes. Correlation between oxide thickness, $\delta$ and the adhesion strength in terms of interfacial fracture toughness, $G_{c}$ was linear. Considering the above results, we might conclude that the main adhesion mechanism of brown-oxide treated leadframe to EMC is mechanical interlocking, in which fine acicular CuO plays a major role.e.

• Journal of the Korean institute of surface engineering
• /
• v.55 no.2
• /
• pp.63-69
• /
• 2022

Preparing various types of thin films of oxide semiconductors is a promising approach to fabricate efficient photoanodes and photocathodes for hydrogen production via photoelectrochemical (PEC) water splitting. In this work, we investigate the feasibility of an efficient photocathode for PEC water reduction of a p-type oxide semiconductor cupric oxide (CuO) thin film prepared via a facile method combined with sputtering Cu metallic film on fluorine-doped thin oxide (FTO) coated glass substrate and subsequent thermal oxidation of the sputtered Cu metallic film in dry air. Characterization of the structural, optical, and PEC properties of the CuO thin film prepared at various Cu sputtering powers reveals that we can obtain an optimum CuO thin film as an efficient PEC photocathode at a Cu sputtering power of 60 W. The photocurrent density and the optimal photocurrent conversion efficiency for the optimum CuO thin film photocathode are found to be -0.3 mA/cm² and 0.09% at 0.35 V vs. RHE, respectively. These results provide a promising route to fabricating earth-abundant copper-oxide-based photoelectrode for sunlight-driven hydrogen generation using a facile method.

• Korean Journal of Materials Research
• /
• v.12 no.1
• /
• pp.58-67
• /
• 2002

In this study copper chloride(CuCl$_2$) solution was used as raw material to produce the fine copper oxide powder which has less than 1 $\mu\textrm{m}$ average particle size and has uniform particle size distribution by spray pyrolysis process. In the present study, the effects of reaction temperature, the injection speed of solution and air, the nozzle tip size and the concentration of raw material solution on the properties of produced powder were studied. The structure of the powder became much more compact with increasing the reaction temperature regardless of copper concentration of the raw material solution. The particle size of the powder increased accordingly with increasing the reaction temperature in case of 30 g/$\ell$ copper concentration of the solution. The particle size of the powder increased accordingly, and the surface structure of the powder became more porous with increasing the copper concentration of the raw material solution. When copper concentration in raw material solution was more than 100 g/$\ell$, all produced powder was CuCl regardless of reaction temperatures. When copper concentration in solution was below 30 g/$\ell$ and reaction temperature was higher than 90$0^{\circ}C$, CuO was the main phase. The surface of the powder tended to become porous with increasing the injection speed of solution. Particle size was increased and the surface of the powder showed severely disrupted state with increasing the nozzle tip size. The particle size was decreased and the particle size distribution was more uniform with increasing the air pressure through the nozzle.