• 한국정밀공학회지
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• 제22권8호
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• pp.27-33
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• 2005

Polishing pads play an important role in chemical mechanical polishing(CMP) which has recently been recognized at the most effective method to achieve global planarization. In this paper, we have investigated CMP characteristics as a change of groove density of polishing pads. The parameter $(K_n)$ is proposed to estimate groove density of pad. The $K_n$ is defined as groove area divided by pitch area. As the groove density value increased, removal rate increased to some point and then gradually saturated in case of increasing the groove density excessively. In addition Within wafer non-uniformity(WIWNU) worse as groove density increased excessively, although WIWNU improved as groove density increased. Also the uniformity of temperature of pad surface decreased as the groove density increased. It was because that the cooling effect increased as groove density increased. In other words, increasing the groove density which means the apparent contact area of pad has influence on amount of discharge of slurry during polishing process.

• 한국안전학회지
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• 제26권2호
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• pp.13-19
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• 2011

The magnetic polishing is the useful method to finish using magnetic power of magnet. That method is one of precision polishing techniques and has an aim of the clean technology using for the pure of gas and inside of the clean pipe. The magnetic abrasive polishing method is not so common for machine that it is not spreaded widely. There are rarely researcher in this field because of non-effectiveness of magnetic abrasive. Therefore, in this paper deals with development of the magnetic abrasive using Sr-Ferrite. In this development, abrasive grain GC used to resin bond fabricated low temperature. And Sr-Ferrite of magnetic abrasive powder fabricated that Sr-Ferrite was crused into 200 mesh. The XRD analysis result show that only GC abrasive and Sr-Ferrite crystal peaks detected which explains resin bond was not any more chemical reaction. From SEM analysis it is found that GC abrasive and Sr-Ferrite were strong bonding with each other by bond. The magnetic polishing is performed by polishing the surface of pipe by attracting magnetic abrasives with magnetic fields. This can be widely applied for finishing machinery fabrications such as various pipes and for other safety processes. In this paper, we could have investigated in to the changes of the movement of magnetic abrasive grain. In reference to this result, we could have made the experiment which is set under the condition of the magnetic flux density, polishing velocity according to the form of magnetic brush.

• Transactions on Electrical and Electronic Materials
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• 제8권1호
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• pp.15-20
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• 2007

Conditioner wear, copper polish rates, pad temperature and coefficient of friction (COF) are measured for two novel Mitsubishi Materials Corporation designs during an extended wear and polishing test. Both designs are coated with a $Teflon^{TM}$ film to reduce substrate wear and chemical attack. Using optical interferometry, changes in the coating that result in gradual changes in diamond exposure are measured. Theories of the COF, conditioning, and polishing are applied to explain the observed performance differences between the designs.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.557-560
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• 2003

Magnetorheological finishing(MRF) is a newly developed and recently commercialized for finishing optical components. The magnetorheological fluid consists of a water based suspension of carbonyl iron, nonmagnetic polishing abrasives, and small amounts of stabilizer. This magnetorheological fluid is pumped from conditioner on the rotating wheel and suctioned back to the conditioner, where it cooled to setpoint temperature and evaporative losses are replaced. This method could produce some problems in suction. So newly designed MRF tools is proposed in which MR fluid is not circulated and conditioned by the slurry. The new polishing mechanism is experimented. Measured surface roughness supports the validity of this mechanism.

• 동굴
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• 제70호
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• pp.45-50
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• 2006

The magnetic polishing is the useful method to finish using magnetic power of magnet. This method is one of precision polishing techniques and has an aim of the clean technology using for the pure of gas and inside of the clean pipe for transportation. The magnetic abrasive polishing method is not so common for machine that it is not spreaded widely. There are rarely researcher in this field because of non-effectiveness of magnetic abrasive. Therefore, in this paper deals with development of the magnetic abrasive using worthless mineral. In this development, abrasive grain WA and GC used to resin bond fabricated low temperature. And magnetic material was fabricated from the worthless mineral which were closed into 200 mesh grit type. The XRD analysis result show that only WA and GC abrasive and worthless mineral crystal peaks detected which explains resin bond was not any more chemical reaction. From SEM analysis it is found that WA and GC abrasive and worthless mineral were strong bonding with each other by bond.

• International Journal of Precision Engineering and Manufacturing
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• 제9권2호
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• pp.39-43
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• 2008

Atmospheric pressure plasma polishing (APPP) is a noncontact precision machining technology that uses low temperature plasma chemical reactions to perform atom-scale material removal. APPP is a complicated process, which is affected by many factors. Through a preliminary theoretical analysis and simulation, we confirmed that some of the key factors are the radio frequency (RF) power, the working distance, and the gas ratio. We studied the influence of the RF power and gas ratio on the removal rate using atomic emission spectroscopy, and determined the removal profiles in actual operation using a commercial form talysurf. The experimental results agreed closely with the theoretical simulations and confirmed the effect of the working distance. Finally, we determined the element compositions of the machined surfaces under different gas ratios using X-ray photoelectron spectroscopy to study the influence of the gas ratio in more detail. We achieved a surface roughness of Ra 0.6 nm on silicon wafers with a peak removal rate of approximately 32 $mm^{3}$/min.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2008년도 추계학술대회 초록집
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• pp.137-137
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• 2008

This paper presents the ability of plasma electrolytic polishing technology to polish surface of stainless steel materials. The results show that the surface of its can be polished clearly using potentiostatic regimes in various concentration of $(NH_4)_2SO_4$ solution that had been warmed to a certain initial temperature. The equipment and deposition produces for polishing process are described and the effect of processing parameters on the characterizations polishedsamples has been has been investigated.

• E2M - 전기 전자와 첨단 소재
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• 제10권7호
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• pp.682-691
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• 1997

We have investigated the guided optical properties of a Ti:LiNbO$_3$optical waveguide which was fabricated by Ti-diffusion in an air atmosphere and proposed an effective polishing method of waveguide endfaces. And the results of guided optical mode and fabrication condition were obtained as follows; \circled1 propagation loss : 0.53 dB/cm \circled2 mode size : horizontal/vertical=12.5${\mu}{\textrm}{m}$ \circled3 mode mismatch : 1.7 dB \circled4 diffusion temperature : 105$0^{\circ}C$, time : 8 hours \circled5 atmosphere : air

• 반도체디스플레이기술학회지
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• 제21권4호
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• pp.71-76
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• 2022

We evaluated and developed a 6th generation large-size polisher in the type of face-up and Oscar. We removed the hillocks of the low temperature poly-silicon (LTPS) thin film with this polisher. The surface roughness of LTPS was lowered from 7.9 nm to 0.6 nm after CMP(chemical mechanical polishing). The thickness of the LTPS is measured through reflectance in real time during polishing, and the polishing process is completed according to this thickness. The within glass non-uniformity (WIGNU) was 6.2% and the glass-to-glass non-uniformity (GTGNU) was 2.5%, targeting the LTPS thickness of 400Å. In addition, the residual slurry after the CMP process was removed through the Core Flow PVA Brush and alkaline chemical.

• 한국주조공학회지
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• 제28권3호
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• pp.124-128
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• 2008

The nitride layer was formed on Ti and Ti-10 wt.%Ta-10 wt.%Nb alloy by a plasma nitriding method. Temperature was selected as the main experimental parameter for plasma nitriding. XRD, EDX, and hardness test were employed to analyze the evolution and material properties of the layer. The SEM observation of TiN nitride layer revealed that the thickness of nitride layer tended to increase with increasing temperature. ${\delta}-TiN$, ${\varepsilon}-Ti_{2}N$ and ${\alpha}-Ti$ phases were detected by XRD analysis and the preferred orientation of TiN nitride layer was obviously observed at (220) plane with increasing temperature. From XRD analysis after step polishing the nitride specimens treated at $850^{\circ}C$, as polishing from the surface, TiN and $Ti_{2}N$ phases decreased gradually. After polishing the surface by $4{\um}m$, a small amount of $Ti_{2}N$ and ${\alpha}-Ti$ phases were observed. The adhesive strength test result indicated that adhesive strength increased with increasing temperature.