• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1264-1268
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• 2004

This paper presents a wafer motion modeling of the transfer unit and the control unit in the clean tube system, which was developed as a means for transferring the air-floated wafers inside the closed tube filled with the super clean airs. The motion in the transfer unit is modeled as a mass-spring-damper system where the recovering force by air jets issued from the perforated plate is modeled as a linear spring. The motion in the control unit is also modeled as another mass-spring-damper system, but in two dimensional systems. Experiments with a clean tube system built for 12-inch wafers show the validity of the presented force and motion models.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.84-88
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• 1999

The behavior of oxygen precipitation was investigated in radial direction using Si wafers with different vacancy-related defects generation area. The behavior of oxygen precipitation in radial direction is strongly dependent on the size of vacancy rich area which is related with crystal growth condition. Oxygen precipitation rate is more enhanced in vacancy rich area than that of interstitial rich area. And anomalous oxygen precipitation is generated in the marginal bands of vacancy and interstial area. In V/I boundary, however, oxygen precipitation is suppressed to nearly perfect.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.47-51
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• 2000

A modified direct bonding technique employing a wet chemical deposition of $SiO_2$ film on a wafer surface to be bonded is proposed for the fabrication of Si-$SiO_2$-Si structures. Structural and electrical quality of the bonded wafers is studied. Satisfied insulating properties of interfacial $SiO_2$ layers are demonstrated. Elastic strain caused by surface morphology is investigated. The diminution of strain in the grooved structures is semi-quantitatively interpreted by a model considering the virtual defects distributed over the interfacial region.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.12 s.255
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• pp.1196-1202
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• 2006

A MEMS methanol reformer was fabricated and its performance was evaluated in the present study. Catalytic steam reforming of methanol was selected because the process had been widely applied in macro scale reformers. Conventional Cu/ZnO catalyst that was prepared by co-precipitation method to give the highest coating quality was used. The reactor structure was made by bonding three layers of glass wafers. The internal structure of the wafer was fabricated by the wet-etching process that resulted in a high aspect ratio. The internal surface of the reactor was coated by catalyst and individual wafers were fusion-bonded to form the reactor structure. The internal volume of the microfabricated reactor was $0.3cm^3$ and the reactor produced exhaust gas with hydrogen concentration at 73%. The production rate of hydrogen was 4.16 ml/hr that could generate power of 350 mW in a typical PEM fuel cell.

• Vacuum Magazine
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• v.3 no.1
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• pp.16-21
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• 2016

FinFETs are able to be scaled down to 22 nm and beyond while suppressing effectively short channel effect, and have superior performance compared to 2-dimensional (2-D) MOSFETs. Bulk FinFETs are built on bulk Si wafers which have less defect density and lower cost than SOI(Silicon-On-Insulator) wafers. In contrast to SOI FinFETs, bulk FinFETs have no floating body effect and better heat transfer rate to the substrate while keeping nearly the same scalability. The bulk FinFET has been developed at 14 nm technology node, and applied in mass production of AP and CPU since 2015. In the development of the bulk FinFETs at 10 nm and beyond, self-heating effects (SHE) is becoming important. Accurate control of device geometry and threshold voltage between devices is also important. The random telegraph noise (RTN) would be problematic in scaled FinFET which has narrow fin width and small fin height.

• The Journal of the Acoustical Society of Korea
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• v.10 no.3
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• pp.19-30
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• 1991

The surface properties such as energy gap, exciton, shallow trap level, deep trap level, type inversion with annealing and metastable state of $EL_2$ level of SI GaAs wafers and the conductivity distribution of 2 inch Cr doped GaAs wafer were investigated using nondestructive TAV(transverse acoustoelectric voltage) technique. The TAV is generated when SAW and semiconductor interact. We also have tried newly SAW oscillator technique to investigate the surface properties of semiconductor wafers and we have shown the validity of this technique.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.06a
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• pp.157-159
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• 1998

Sapphire crystals were grown by Horizontal Bridgman method. The effects of sliding rate (growth rate) of Molybdenum container, growth atmosphere, temperature gradient and orientation of see on crystal qualities were investigated. The size of the crystals grown was up to 150-200 mm in length, 90 mm in width and 25-35 mm in thickness. Crystals grown under the optimum conditions were colorless, transparent and could not be observed and macroscopic defects, such as bubbles, cracks, twins and mosaic structure. With the grown crystals, prototypes of sapphire substrate for blue wafers were characterized. As a result, we can get hight quality of sapphire wafers with c-axis, 1.5 inches in diameters and 0.33 mm in thickess.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.4 s.235
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• pp.632-638
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• 2005

The surface lapping process on sapphire wafer was carried out for the epitaxial process of thin film growth of GaN semiconducting material. The planarization of the wafers was investigated by the introduction of the dummy wafers. The diamond lapping process causes the surface deformation of dislocation and micro-cracks. The material deformation due to the mechanical stress was analyzed by the X-ray diffraction and the Vickers indentation. The fracture toughness was increased with the increased annealing temperature indicating the recrystallization at the surface of the sapphire wafer The sudden increase at the temperature of $1200^{\circ}C$ was correlated with the surface phase transition of sapphire from a $-A1_{2}O_{3}\;to\;{\beta}-A1_{2}O_{3}$.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.1
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• pp.1-6
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• 2012

The polishing of silicon wafers has an important role in semiconductor manufacturing. Generally, getting a flat surface such as a mirror is the purpose of the process. The wafer surface roughness is affected by many variables such as the characteristics of the carrier head unit, operation, speed, the pad and slurry temperature. Optimum process conditions for experimental temperature, pH value, down-force, slurry ratio are investigated, time is used as a fixed factor. This study carried out a series of experiments at varying platen, chuck rpm and oscillation cpm taking particular note of the difference between the rpm and the affect it has on the surface roughness. In this experiment determine the optimum conditions for polishing silicone wafers.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.705-708
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• 2003

To observe a hydrated biological specimen, an environmental chamber was necessary to keep the specimen in a wet state under vacuum surroundings. The specimen holder is as follows designed consequently. The specimen holder consisted of two Si wafers, the centers of which were Si$_3$N$_4$(100nm thickness) windows of a 0.3mm square. The windows were made by a photo-lithographic method. The transmission of a window at 400eV is about 70%. A hydrated biological specimen was put between the two windows. When the chamber was closed, two wafers were contact at the metal mesh by the pressure of O-rings, and the specimen holder moved by the three micrometers.