• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1309-1312
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• 2005

A multi-chemical supply system is developed and applied to a wet station, which uses the multi-chemical process in one bath. To control the concentration of two chemicals, control logic of a supply pump is programmed using the programable logic controller (PLC). By using the multi-chemical supply system, wet station with single bath is applied to cleaning process using multi chemicals such as buffed oxide etchant (BOE) and standard clean 1 (SC-1). The concentration of each chemical is measured in the bath to verify the multi-chemical supply system. The control range in the each chemical concentration is measured to 1.33weight% in NH4OH and 0.23weight% in H2O2. The multi-chemical supply system can be movable and usable as an independent module of fixed wet station. By simply midifying the PLC, a multi-chemical supply system can be developed for a wet station.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.4
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• pp.63-69
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• 1994

The Ultrahigh Vacuum Electron Cyclotron Resonance Chemical Vapor Deposition(UHV-ECRCVD) system whose base pressure is 1${\times}10^{9}$ torr has been constructed. In-situ cleaning prior to the epitaxial growth was carried out at 56$0^{\circ}C$ by ECR generated uniform hydrogen plasma whose density is $10^{10}/cm{3}$. The natural oxide was effectively removed without damage by applying positive DC bias(+10V) to the substrate. RHEED(Reflection High Energy Electron Diffraction) analysis has been used to confirm the removal of the surgace oxide and the streaky 2$\times$1 reconstruction of the Si surface, and the suppression of the substrate damage is anaylized by X-TEM(cross-sectional Transmission Electron Microscopy). Surface cleaning technique by ECR hydrogen plasma confirmed good quality epitaxial growth at low temperature.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.7
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• pp.424-432
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• 2000

The plasma surface treatment, using hydrogen gas, of the silicon wafer was investigated as a pretreatment for the application to silicon-on-insulator (SOI) wafers using the silicon direct bonding technique. The chemical reactions of hydrogen plasma with surfaces were used for both the surface activation and the removal of surface contaminants. As a result of exposure of silicon wafer to the plasma, an active oxide layer was formed on the surface, which was rendered hydrophilic. The surface roughness and morphology were estimated as functions of plasma exposing time as well as of power. The surface became smoother with decreased incident hydrogen ion flux by reducing plasma exposing time and power. This process was very effective to reduce the carbon contaminants on the silicon surface, which was responsible for a high initial surface energy. The initial surface energy measured by the crack propagation method was 506 mJ/m2, which was up to about three times higher than that of a conventional RCA cleaning method.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3279-3281
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• 1999

This paper describes a method of direct wafer bonding using surfaces activated by a radio-frequency hydrogen plasma. The hydrogen plasma cleaning of silicon in the RIE mode was investigated as a pretreatment for silicon direct bonding. The cleaned silicon surface was successfully terminated by hydrogen, The hydrogen-terminated surfaces were rendered hydrophilic, which could be wetted by Dl water rinse. Two wafers of silicon and silicon dioxide were contacted to each other at room temperature and postannealed at $300{\sim}1100^{\circ}C$ in an $N_2$ atmosphere for 2 h. From the AFM results, it was revealed that the surface became rougher with the increased plasma exposure time and power. The effect of the plasma treatment on the surface chemistry was investigated by the AES analysis. It was shown that the carbon contamination at the surface could be reduced below 5 at %. The interfacial energy measured by the crack propagation method was 122 $mJ/m^2$ and 384 $mJ/m^2$ for RCA cleaning and hydrogen plasm, respectively.

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

• Journal of Advanced Navigation Technology
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• v.14 no.3
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• pp.426-431
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• 2010

68% of the manufacturing costs of solar cell wafer can be attributed to the slurry. The recycling of slurries is mandatory for reducing the costs of manufacturing wafering production, and the disposal of industrial waste, as well as for cutting down pollution levels. Slurries are currently being recycled using the centrifuge(decanter) method. However, this method is less than optimal as it does not completely remove the fine particles, leading to low quality. Also, be cause of the incomplete separation from the oil, it causes the impurities in the dried slurries. This study aims to develope a new recycling technology that overcomes the flaws of the centrifuge by utilizing chemicals. It will provide a total solution to the crucial process of recycling slurries in the making of solar cell wafer, by increasing the efficiency and renewable rate.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3310-3312
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• 1999

We have studied the method of silicon direct bonding using the mixture of $HNO_$, $H_2O_2$, and HF chemicals called the controlled slight etch (CSE) solution for the effective wafer cleaning. CSE, two combinations of oxidizing and etching agents, have been used to clean the silicon surfaces prior to wafer bonding. Two wafers of silicon and silicon dioxide were contacted each other at room temperature and postannealed at $300{\sim}1100^{\circ}C$ in $N_2$ ambient for 2.5 h. We have cleaned silicon wafers with the various HF concentrations and characterized the parameters with regard to surface roughness, chemical nature, chemical oxide thickness, and bonding energy. It was observed that the chemical oxide thickness on silicon wafer decreased with increasing HF concentrations. The initial interfacial energy and final energy postannealed at $1100^{\circ}C$ for 2.5h measured by the crack propagation method was 122 $mJ/m^2$ and 2.96 $mJ/m^2$, respectively.

• Korean Journal of Materials Research
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• v.4 no.8
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• pp.921-926
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• 1994

The characteristics of gate oxide significantly depend on the last chemical solution used in cleaning process. The standard RCA, HF-last, SC1-last, and HF-only processes are the pre-gate oxide cleaning processes utilized in this experiment. Cleaning process was followed by thermal oxidation in oxidation furnace at $900^{\circ}C$. A 100$\AA$ gate oxide was grown and characterized with using lifetime detector, VPD AAS, SIMS, TEM, and AFM. The results of HF-last and HF-only were shown to be very effective to remove the metallic impurities. And these two splits also showed long minority carrier lifetimes. The surface and interface morphologies of the oxide were examined with AFM and TEM. The rough surface morphologies were observed with the cleaning splits containing the SC1 solution. The smooth surface and interface was observed with the HF-only cleaning process.

• Korean Journal of Materials Research
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• v.8 no.9
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• pp.837-842
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• 1998

As the size of the integrated circuit is scaled down the importance of Si cleaning has been emphasized. One of the major concerns is abut the removal of metallic impurities such as Cu and Fe on Si surface. In this study, we intentionally contaminated Cu and Fe on the Si wafers and cleaned the wafer by cleaning splits of the chemical mixture of $\textrm{H}_2\textrm{O}_2$ and HF and the combination of HF treatment with UV/$\textrm{O}_3$ treatment. The contamination level was monitored by TXRF. Surface microroughness of the Si wafers was measured by AFM. The Si wafer surface was examined by SEM. AES analysis was carried out to analyze the chemical composition of Cu impurities. The amount of Cu impurities after intentional contamination was abut the level of $\textrm{10}^{14}$ atoms/$\textrm{cm}^2$. The amount of Cu was decreased down to the level of $\textrm{10}^{10}$ atoms/$\textrm{cm}^2$ by cleaning splits. The repeated treatment exhibited better Cu removal efficiency. The surface roughness caused by contamination and removal of Cu was improved by repeated treatment of the cleaning splits. Cu were adsorbed on Si surface not in a thin film type but in a particle type and its diameter was abut 100-400${\AA}$ and its height was 30-100${\AA}$. Cu was contaminated on Si surface by chemical adsorption. In the case of Fe the contamination level was $\textrm{10}^{13}$ atoms/$\textrm{cm}^2$ and showed similar results of above Cu cleaning. Fe was contaminated on Si surface by physical adsorption and as a particle type.

• Journal of Sensor Science and Technology
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• v.15 no.4
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• pp.245-250
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• 2006

In this paper, glass cap wafer for MEMS device package is fabricated by using sand blaster dry etcher and Its surface is studied. The surface of dry etched glass is analyzed by using SEM, and many glass particles and micro cracks are observed. If these kind of particles were dropped from glass to the surface of device, It would make critical failure to the operation of device. So, several cleaning and etching methods are induced to remove these kinds of dormant failure mode and optimized condition is found out.