• 한국공작기계학회논문집
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• 제12권5호
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• pp.40-45
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• 2003

Optical and electronic industries are using lapping and polishing processing as a final finish rather than grinding, because they need more accurate parts of brittles non-metallic materials such as single crystals. Sapphire has been ground by the ultra-precision surface grinder having a glass -ceramic spindle of extremely-low thermal expansion with various cup-type resinoid-bonded diamond wheels of #400-#3000 in grain size. Sapphire can be ground in the ductile mode. And also, the surface roughness and grinding conditions has been clarified. The smooth surface of Sapphire less than 1nm RMS, 1nm Ra can be obtained by the ultra-precision grinding without any polishing process.

• 한국생산제조학회지
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• 제20권3호
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• pp.304-309
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• 2011

A monitoring system for magnetic abrasive polishing process is necessary to ensure the polishing products the high quality and integrity. Acoustic emission (AE) signal is known to reflect the material removal phenomena in other machining processes. In a case of the magnetic abrasive polishing of non-magnetic materials, application of AE method is very difficult because of lower machining force on the surface of workpiece and the level of AE signal is extremely lower. In this study, AE sensor-based monitoring system is applied to the magnetic abrasive polishing. The relation between the level of the AE RMS and the surface roughness during the magnetic abrasive polishing of magnesium alloy steel is investigated.

• Applied Science and Convergence Technology
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• 제23권3호
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• pp.145-150
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• 2014

MgO thin films were deposited by internal ICP-assisted reactive-magnetron sputtering with bipolar pulse bias on a substrate to suppress random arcs. Mg is reactively sputtered by a bipolar pulsed DC power of 100 kHz into ICP generated by a dielectrically shielded internal antenna. At a mass flow ratio of $Ar/O_2$ = 10 : 2 and an ICP/sputter power ratio of 1 : 1, optimal film properties were obtained (a powder-like crystal orientation distribution and a RMS surface roughness of approximately 0.42 nm). A bipolar pulse substrate bias at a proper frequency (~a few kHz) prevented random arc events. The crystalline preferred orientations varied between the (111), (200) and (220) orientations. By optimizing the plasma conditions, films having similar bulk crystallinity characteristics (JCPDS data) were successfully obtained.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.330-333
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• 2005

The fabrication of mold fur nano imprint lithography (NIL) is experimentally reported using the scanning probe lithography (SPL) technique, instead of the conventional I-beam lithography technique. The nanometer scale patterning structure is fabricated by the localized generation of oxide patterning on the silicon (100) wafer surface with a thin oxide layer, The fabrication method is based on the contact mode of scanning probe microscope (SPM) in air, The precision cleaning process is also performed to reach the low roughness value of $R_{rms}=0.084 nm$, which is important to increase the reproducibility of patterning. The height and width of the oxide dot are generated to be 15.667 nm and 209.5 nm, respectively, by applying 17 V during 350 ms.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2007년도 춘계학술발표회 초록집
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• pp.69-70
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• 2007

FTS(Facing Target Sputtering) 장치를 이용하여 polyethylene terephthalate (PET) 필름 위에 ITO(Indium Tin Oxide) 박막을 성장시키고 이들의 광학적, 구조적 특성을 조사하였다. 막 두께는 150 nm로 고정하였고, 인가적력과 산소 가스 유량비를 변수로 박막을 합성 하였다. 그 결과 80 % 이상의 광투과율과 Rms 26.8 nm 값을 갖는 ITO / PET 박막을 합성하였다.

• 대한원격탐사학회지
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• 제17권2호
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• pp.141-153
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• 2001

A semi-empirical polarimetric backscattering model for bare soil surfaces is presented. Based on measurements by using polarimetric scatterometers and the JPL AirSAR, as well as the theoretical models, the backscattering coefficints $\sigma$$^0_w$, $\sigma$$^0_{hh}$ and $\sigma$$^0_{vh}$, and the parameters of the copolarized phase-difference probability density function, namely the degree of correlation $\alpha$ and the copolarized-phase-difference $\zeta$, are modeled empirically in terms of the volumetric soil moisture content m$_v$ and the surface roughness parameters $k_s$ and $k_l$, where k=2$\pi$f/c, s is the rms height and l is the correlation length.

• 한국진공학회지
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• 제4권S2호
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• pp.24-29
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• 1995

The magnetic amd magneto-optical(MO)properties of Co-based multilayered(ML)films are known to vary sensitively according to the manufacturing methods and the film microstructures. Co/Pd and Co/Pt ML films with ultrathin layers of Co were prepared by alternating deposition in an ultrahigh-vacuum physical-vapor-deposition system. The individual layer thicknesses of the samples were estimated making use of the angular positions of x-ray diffraction peaks. The magnetic and MO properties were investigated, and correlated systematically to the structural parameters of the films. A Kerr spectrometer was self-manufactured to measure the MO properties such as Kerr rotation angle, ellipticity and reflectivity. The rms surface roughness was also measured using atomic force microscopy. Some of the samples showed good properties for MO medium, such as large perpendicular magnetic anisotropy and Kerr rotation, and perfect squareness of the magnetic hysteresis loop.

• Journal of Ceramic Processing Research
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• 제13권spc1호
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• pp.78-81
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• 2012

Colloidal titania nanoparticles were synthesized by a simple sol-gel process. The obtained nanoparticles showed high crystallinity and were of the anatase type. These crystalline colloidal titania nanoparticles were organically modified using methyl- and glycidyl-grafted silanes in order to enhance their stability and solution processability. The stabilized colloidal titania nanoparticles could be dispersed homogeneously without aggregation and converted into silica-titania hybrid films with the heterogeneous Si-O-Ti bonds by a low-temperature solution process. The fabricated silica-titania hybrid films showed high transparency (~ 90%) in the visible range, and low RMS roughness (<1 nm). Therefore, the organosilane-modified crystalline colloidal titania nanoparticles can be used in solution-processable functional coatings for electro-optical devices.

• 한국재료학회지
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• 제19권2호
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• pp.68-72
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• 2009

This study investigated dry etching of acrylic in capacitively coupled $SF_6$, $SF_6/O_2$ and $SF_6/CH_4$ plasma under a low vacuum pressure. The process pressure was 100 mTorr and the total gas flow rate was fixed at 10 sccm. The process variables were the RIE chuck power and the plasma gas composition. The RIE chuck power varied in the range of $25{\sim}150\;W$. $SF_6/O_2$ plasma produced higher etch rates of acrylic than pure $SF_6$ and $O_2$ at a fixed total flow rate. 5 sccm $SF_6$/5 sccm $O_2$ provided $0.11{\mu}m$/min and $1.16{\mu}m$/min at 25W and 150W RIE of chuck power, respectively. The results were nearly 2.9 times higher compared to those at pure $SF_6$ plasma etching. Additionally, mixed plasma of $SF_6/CH_4$ reduced the etch rate of acrylic. 5 sccm $SF_6$/5 sccm $CH_4$ plasma resulted in $0.02{\mu}m$/min and $0.07{\mu}m$/min at 25W and 150W RIE of chuck power. The etch selectivity of acrylic to photoresist was higher in $SF_6/O_2$ plasma than in pure $SF_6$ or $SF_6/CH_4$ plasma. The maximum RMS roughness (7.6 nm) of an etched acrylic surface was found to be 50% $O_2$ in $SF_6/O_2$ plasma. Besides the process regime, the RMS roughness of acrylic was approximately $3{\sim}4\;nm$ at different percentages of $O_2$ with a chuck power of 100W RIE in $SF_6/O_2$ plasma etching.

• 한국전자파학회논문지
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• 제25권12호
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• pp.1219-1227
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• 2014

펄스 레이저 증착(Pulsed laser Deposition: PLD) 및 RF 스퍼터링 증착(Sputtering Deposition)의 단계적 적용을 통해, 표면탄성파 대역 통과 필터(Surface Acoustic Wave Bandpass Filter: SAW-BPF)용 ZnO 박막을 성장시켰다. PLD 방법으로 성장된 ZnO 박막위에 RF sputtering 방법을 사용하여 ZnO 박막을 재증착시켰으며, 성장된 ZnO 박막의 물성을 분석하기 위하여 XRD, SEM 및 AFM 분석장비를 사용하였다. 두 가지 증착 방법이 단계적으로 적용되어 성장된 ZnO 박막의 경우, 결정성과 배향성이 우수하게 유지되면서 표면거칠기가 향상되었다. 분석 결과, ${\omega}$-scan의 반치폭과 표면거칠기의 RMS 값은 각각 $0.79^{\circ}$와 1.108 nm였다. 그리고 성장된 양질의 ZnO 박막을 사용하여 SAW-BPF를 제작하여 측정한 결과는 응답 특성의 중심주파수가 260.8 MHz, 대역폭은 2.98 MHz, 그리고 삽입손실은 36.5 dB이었다.