• Transactions on Electrical and Electronic Materials
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• v.10 no.3
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• pp.71-74
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• 2009

Electroplated Cu is a cost efficient metallization method in microelectronic packaging applications. Typically in 3-D chip staking technology, utilizing through silicon via (TSV), electroplated Cu metallization is inevitable for the throughput as well as reducing the cost of ownership (COO).To achieve a comparable film quality to sputtering or CVD, a pre-cleaning process as well as plating process is crucial. In this research, atmospheric plasma is employed to reduce the usage of chemicals, such as trichloroethylene (TCE) and sodium hydroxide (NaHO), by substituting the chemical assisted organic cleaning process with plasma surface treatment for Cu electroplating. By employing atmospheric plasma treatment, marginally acceptable electroplating and cleaning results are achieved without the use of hazardous chemicals. The experimental results show that the substitution of the chemical process with plasma treatment is plausible from an environmentally friendly aspect. In addition, plasma treatment on immersion Sn/Cu was also performed to find out the solderability of plasma treated Sn/Cu for practical industrial applications.

• Journal of The Korean Digital Architecture Interior Association
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• v.13 no.4
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• pp.61-68
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• 2013

Concrete structure is not the only material vulnerable to physical and chemical processes of deterioration associates with severe conditions. Deterioration of the concrete structure, however, occurs more progressively from the outside of the concrete exposed to severe conditions. Especially, Carbonation, chloride ion attack is more important factor of concrete durability. This study is interested in manufacturing the self-cleaning concrete surface impregnant including TEOS, lithium silicate for the repair of the exposed concrete surface and the color concrete requiring the advanced function in view of the concrete appearance. Form the results, TEOS and lithium silicate are very effective that increasing the concrete durability using self-cleaning concrete impregnant. Self-cleaning concrete impregnant specimens is satisfied with performance requirement of KS standard in adhesion test in tension but the reinforcement of concrete substrate is slight. So, the self-cleaning concrete impregnant of this study is more desirable for the improvement of durability rather than the reinforcement.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.12
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• pp.1107-1113
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• 2014

In this article, the megasonic cleaning system for cleaning micro/nano particles from flat panel display (FPD) surfaces was developed. A piezoelectric actuator and a waveguide were designed by finite element method (FEM) analysis. The calculated peak frequency value of the quartz waveguide was 1002 kHz, which agreed well with the measured value of 1003 kHz. The average acoustic pressure of the megasonic cleaning system was 43.1 kPa, which is three times greater than that of the conventional type of 13.9 kPa. Particle removal efficiency (PRE) tests were performed, and the cleaning efficiency of the developed system was proven to be 99%. The power consumption of the developed system was 64% lower than that of the commercial system. These results show that the developed megasonic cleaning system can be an effective solution in particle removing from FPD substrate with higher energy efficiency and lower chemical and ultra pure water (UPW) consumption.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.24.1-24.1
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• 2010

In practical operation, the exposed surfaces may get dirty thus degrade the performance of devices. So the combination of self cleaning and antireflection is very desirable for use in outdoor photovoltaic and displaying devices, self cleaning windows and car windshields. For the purpose of self cleaning, the surface needs to be either superhydrophobic or superhydrophilic. However, in practice AR in the visible region and self cleaning are a pair of competitive properties. To satisfy the requirements for superhydrophobic or superhydrophilic surfaces, high surface roughness is required. But it usually cause severely light scattering. Photo-responsive coatings (TiO2, ZnO etc.) can lead to superhydrophilic. However, the refractive indices are high. Thus for porous structure, controlling pore size in the underwavelength scale to reduce the light scattering is very crucial for highly transparent and self cleaning antireflection coating. Herein, we demonstrate a simple method to make high performance broadband antireflection layer on the glass surface, by "carving" the surface by hot alkali solution. Etched glass has superhydrophilic surface. By chemical modification, it turns to superhydrophobic. Enhanced transparency (up to 97%) in a broad wavelength range was obtained by short time etching. Also antifogging effect has been demonstrated, which may offer advantage for devices working at high humidity environment or underwater. Compositional dependence of the properties was observed by comparing three different commercially available glasses.

• Journal of the Semiconductor & Display Technology
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• v.10 no.4
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• pp.139-144
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• 2011

CMP process is an essential element in the semiconductor product processes in Chemical Mechanical Polishing. Taken as a whole, CMP is one process, but concretely, it is a detail process which consists of polishing, cleaning, and so on. Especially, the polishing and cleaning are key points in the whole process. Polishing rate is the most important factor and is related with deposition of slurry in the polishing process. Each outlet velocities is the most important factors in cleaning process. And when the velocities are more uniform, the cleaning becomes more effective. In this research, based on these factors, we performed a numerical analysis for effective polishing and cleaning which can be applied to industrial field. Consequently, we figured out that more than one opened nozzle is more effective than one opened nozzle at the polishing pad in case of this research. And we confirmed that the revised models have the uniform velocity distribution more than the previous model of the cleaning nozzle.

• Korean Chemical Engineering Research
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• v.45 no.2
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• pp.203-207
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• 2007

In this paper efficient method for particle removal from silicon wafers by usage of HF and ozone was studied. It was found that at least 0.3 vol% concentration of HF was required for particle removal and removal efficiency increased with the application of megasonic in ozonated water. Additional cleaning with minute amount of ammonia (0.01 vol%) after HF/Ozone step showed over 99% in removal efficiency. It is proposed that the superior cleaning efficiency of HF-Ozone-ammonia is due to micro-etching of silicon surface and impediment of particle re-adsorption in alkali environment. Compared to SC-1 cleaning method micro roughness has also been slightly improved. Therefore it is expected that HF-ozone-ammonia cleaning method is a viable alternative to the conventional wet cleaning methods.

• Clean Technology
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• v.18 no.1
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• pp.43-50
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• 2012

Cleaning procedure of solar silicon wafer, following ingot sawing process in solar cell production is studied. Types of solar silicon wafer can be divided into monocrystalline or multicrystalline, and slurry sawn wafer or diamond sawn wafer according to the ingot growing methods and the sawing methods, respectively. Wafer surface and contaminants can vary with these methods. The characterisitics of contaminants and wafer surface are investigated for each cleaning substrate, and appropriate cleaning agents are developed. Physical properties and cleaning ability of the cleaning agents are evaluated in order to verify the application in the industry. The wafers cleaned with the cleaning agents do not show any residual contaminants when analyzed by XPS and regular patterns are formed after texturization. Furthermore, the cleaning agents are applied in the production industry, which shows superior cleaning results compared to the existing cleaning agents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.1016-1022
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• 2010

An Experimental study of cleaning solution has been performed on a high capacity steam boiler burning heavy fuel oil to on-line cleaning of deposit. The deposit is mixture of soot, slag, ash, metal oxide and clinker. The traditional technology of deposit cleaning was carried hand-crafted. The conventional technology of boiler cleaning method is mechanical removal by the worker while the boiler shut down operation. In this experiment, the deposit of mixture of soot, slag, ash, metal oxide and clinker has been removed by the cleaning agents without shut down of boiler burning. This study found out the optimum cleaning solution composition. The best results have been obtained when the mixture of ammonium nitrate and $MgNO_3$ were used in cleaning solution. The various transition metal effect was investigated for optimum mixing condition. In this research, the metal compound additive of the clean solution compoition was obtained. The combustion efficiency was improved by on-line cleaning with derived clean solution compoition. On-line cleaning method prevents the fouling and corrosion in the boiler and heat exchanger.

• Clean Technology
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• v.18 no.3
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• pp.287-294
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• 2012

In this study, performances of two cleaning methods were analyzed and a cleaning system was designed to develop a cleaning process of electronic components to remanufacture old laser copy machine. First, plasma cleaning as a dry cleaning method was executed to test cleaning ability. In cleaning of printed circuit board (PCB) by plasma, some damages were found near the metal parts, and considering the productivity, this method was not adequate for the cleaning of electronic components. With 4 different cleaning agents, ultrasonic cleaning tests were executed to select an optimal cleaning agent, aqueous agents showed superior cleaning performance compared to semi-aqueous and non-aqueous agents. Cleaning with aqueous cleaning agent A and 28 kHz ultrasonic frequency can be completed in 30 sec to 1 min. Finally, an ultrasonic cleaning system was constructed based on the pre-test results. Optimal cleaning conditions of 40 kHz and $50^{\circ}C$ were found in the field test. The productivity and economic efficiency in remanufacturing of laser copy machine are expected to increase by adapting developed ultrasonic cleaning system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.2043-2048
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• 2013

OPR-1000 CE Steam Generator, of which tube material is composed of Alloy-600 HTMA in nuclear power plant, secondary side is generated ODSCC(Outside Diameter Stress Corrosion Cracking) due to the accumulated sludge. ODSCC is centered around the tube sheet and is being affected depending on the height of the sludge. Chemical cleaning was carried out for a top-of-the-tube sheet(TTS) of Steam Generator in order to decrease corrosive condition of the secondary side of Steam Generator tubes and suppress the occurrence of stress corrosion cracking. The amount of sludge removal was 259.2kg. The height of the accumulated sludge was reduced from 0.71 to 0.34 inches. Corrosion rate as the maximum 2.34 mils was satisfied to within EPRI (Electric Power Research Institute) recommendation(10 mils).