• Journal of the Korean Ceramic Society
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• v.39 no.3
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• pp.278-285
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• 2002

For planar optical devices, silica film deposited by FHD was fabricated at low temperature. To prepare silica film at low temperature, we have changed B, P amounts and investigated consolidation effect with varying consolidation temperature and atmosphere on microstructural change, and also observed optical property. The optimum consolidation temperature in He was lower than that of other atmosphere, its temperature could be lowered to 1050$^{\circ}C$. As a result, the roughness of flat silica film prepared at 1050$^{\circ}C$ showed 5, 6nm.

• KSBB Journal
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• v.17 no.4
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• pp.350-356
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• 2002

Low density polyethylene(LDPE) film was fabricated with the addition of benzoic acid, or/and JP which contained water-soluble silica adsorbed a natural antimicrobial compounds. The used antimicrobial compounds were isolated from culture broths of methylotropic actinomycetes strains MO-16 and MO-17 which was newly isolated from soils. An antimicrobial compound retained antimicrobial activity after heat treatment at 121$^{\circ}C$ for 5 min. JP, which obtained from Japan as a antimicrobial agent, showed antimicrobial activity in the concentration of 100 mg/mL. The silica LDPE film revealed the growth inhibition of total aerobic bacteria in packaged minced pork compared with commercial film and of E. coil on a contained agar plate. In the storage testing of various packaged foods at room temperature for 30 days, the film showed excellent preservation compared with commercial film in case of small tomato and Agaricus bisporus.

• ETRI Journal
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• v.25 no.2
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• pp.73-80
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• 2003

This paper describes an effective method for forming silicon oxide on silica-on-silicon platforms, which results in excellent characteristics for hybrid integration. Among the many processes involved in fabricating silica-on-silicon platforms with planar lightwave circuits (PLCs), the process for forming silicon oxide on an etched silicon substrate is very important for obtaining transparent silica film because it determines the compatibility at the interface between the silicon and the silica film. To investigate the effects of the formation process of the silicon oxide on the characteristics of the silica PLC platform, we compared two silicon oxide formation processes: thermal oxidation and plasma-enhanced chemical vapor deposition (PECVD). Thermal oxidation in fabricating silica platforms generates defects and a cristobalite crystal phase, which results in deterioration of the optical waveguide characteristics. On the other hand, a silica platform with the silicon oxide layer deposited by PECVD has a transparent planar optical waveguide because the crystal growth of the silica has been suppressed. We confirm that the PECVD method is an effective process for silicon oxide formation for a silica platform with excellent characteristics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.35-37
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• 2005

100, 200nm 크기의 colloidal silica 각각에 나노 ceria 입자를 수열합성법으로 코팅하였다. Colloidal silica 입자에 ceria를 코팅 시 slurry의 pH조절과 수열처리에 이용하여 silica에 ceria가 코팅됨을 TEM과 zeta-potential을 이용하여 확인하였다. 연마 슬러리의 분산 안정성과 연마효율을 높이기 위하여 슬러리의 pH 는 9로 하였으며, 이때의 zeta-potential 값은 -25 mV이었다. 1 wt%로 제조된 연마슬러리를 이용하여, 4 inch $SiO_2$, $Si_3N_4$ wafer를 압력변화에 따른 연마특성을 관찰 하였다. Ceria coated colloidal silica 100 nm, 200 nm와 commercial한 $CeO_2$입자를 연마압력 6 psi로 oxide film을 연마한 결과 연마율이 각각 2490 ${\AA}/min$, 4200 ${\AA}/min$, 4300 ${\AA}/min$으로 측정되었다. 또한 $SiO_2$, $Si_3N_4$ film의 6 psi압력에서 ceria coated colloidal silica 100 nm, 200 nm와 commercial 한 $CeO_2$입자의 선택비는 3, 3.8, 6.7 이었다. 입자크기가 클수록 연마율이 높으며, Preston equation을 따라 연마 압력과 연마율이 비례하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.161-161
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• 2008

The oxide film of silicon wafer has been mainly polished by fumed silica, colloidal silica or ceria slurry. Because colloidal silica slurry is uniform and highly dispersed composed of spherical shape particles, by which the oxide film polished remains to be less scratched in finishing polishing process. Even though the uniformity and spherical shape is advantage for reducing the scratch, it may also be the factor to decrease the removal rate. We have studied the correlation of silica abrasive particles and CMP characteristics by varying pH, down force, and table rotation rate in polishing. It was found that the CMP polishing is dependent on the morphology, aggregation, and the surface property of the silica particles.

• Korean Journal of Materials Research
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• v.15 no.12
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• pp.818-823
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• 2005

Sub-micron colloidal silica particles coated with nano-sized ceria were prepared by mixing of its silica and cerium salts hydrolysis, and modified by hydrothermal reaction. By using the slurries with and without hydrothermal modification containing above particles, oxide film coated on silicon wafer was polished. The modified slurries had higher polish rate due to increase of ceria fraction to silica through hydrothermal reaction. They revealed higher stability in wide range of pH $2\~10$ than ceria coated silica slurries without its modification.

• Tribology and Lubricants
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• v.22 no.4
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• pp.182-189
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• 2006

In this paper, the adhesion characteristics between a fused silica without or with an anti-sticking layer and a thermoplastic polymer film used in thermal NIL were investigated experimentally in order to identify the release performance of the anti-sticking layer. The anti-sticking layers were derived from fluoroalkylsilanes, (1H, 1 H, 2H, 2H-perfluorooctyl)trichlorosilane ($F_{13}-OTS$) and (3, 3, 3-trifluoropropyl)trichlorosilane (FPTS), and coated on the silica surface in vapor phase. The commercial polymers, mr-I 7020 and 8020 (micro resist technology, GmbH), for thermal NIL were spin-coated on Si substrate with a rectangular island which was fabricated by conventional microfabrication process to achieve small contact area and easy alignment of flat contact sur- faces. Experimental conditions were similar to the process conditions of thermal NIL. When the polymer film on the island was separated from the silica surface after imprint process, the adhesion force between the silica surface and the polymer film was measured and the surfaces of the silica and the polymer film after the separation were observed. As a result, the anti-sticking layers remarkably reduced the adhesion force and the surface damage of polymer film and the chain length of silane affects the adhesion characteristics. The anti-sticking layers derived from FPTS and $F_{13}-OTS$ reduced the adhesion force per unit area to 38% and 16% of the silica sur-faces without an anti-sticking layer, respectively. The anti-sticking layer derived from $F_{13}-OTS$ was more effective to reduce the adhesion, while both of the anti-sticking layers prevented the surface damages of the polymer film. Finally, it is also found that the adhesion characteristics of mr-I 7020 and mr-I 8020 polymer films were similar with each other.

• Korea-Australia Rheology Journal
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• v.16 no.4
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• pp.175-182
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• 2004

Colloidal coating solution was prepared to enhance the hydrophilic property of the film surface. Water and ethanol were used as the dispersion media and (glycidoxypropyl) trimethoxysilane (GPS) as a binder in the colloidal silica coatings. Ethylene diamine was added to the colloidal silica solution as the curing agent. The colloidal silica solution was regarded as a hard-sphere suspension model with low volume fraction of the silica particles. Rheological properties of the silica suspensions modified with GPS have been investigated as a function of pH and concentration. The acidic solution showed high viscosity change by fast hydrolysis reaction and adsorption of the organic binders on the surface of silica particles. However, the hydrolysis was slow at the basic condition and the binders combined with themselves by condensation. The viscosity change was smallest at pH 7. The viscosity increased with the curing time after adding ethylenediamine, and the increase of viscosity at low pH was higher than that at high pH. The hydrophilic properties of the coating film were investigated by the contact angle of water and film surface. The smallest contact angle was shown under the strong acidic condition of pH 2.

• Transactions on Electrical and Electronic Materials
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• v.7 no.4
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• pp.167-172
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• 2006

Submicron colloidal silica coated with ceria were prepared by mixing of silica and nano ceria particles and modified by hydrothermal reaction. The polishing efficiency of the ceria coated silica slurry was tested over oxide film on silicon wafer. By changing the polishing pressure in the range of $140{\sim}420g/cm^2$ with the ceria coated silica slurries in $100{\sim}300nm$, rates, WIWNU and friction force were measured. The removal rate was in the order of 200, 100, and 300 nm size silica coated with ceria. It was known that the smaller particle size gives the higher removal rate with higher contact area in Cu slurry. In the case of oxide film, the indentation volume as well as contact area gives effect on the removal rate depending on the size of abrasives. The indentation volume increase with the size of abrasive particles, which results to higher removal rate. The highest removal rate in 200 nm silica core coated with ceria is discussed as proper combination of indentation and contact area effect.

• Journal of the Korean Ceramic Society
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• v.45 no.2
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• pp.87-89
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• 2008

A nano structured silica aerogel thin film was manufactured from inexpensive sodium silicate (water glass) using an ambient pressure drying method. High purity silicic sol was prepared by passing a water glass solution through an ion exchange resin, and the gel films were prepared on a modified glass substrate via dip coating. The dip coating conditions, such as coating time and solvent, were optimized. The optical and physical properties of the obtained silica aerogel thin film were characterized using a UV-visable spectrometer and a scanning electron microscope.