• 동굴
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• 제81호
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• pp.1-5
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• 2007

The magnetic polishing is the useful method to finish some machinery fabrications by using magnetic power This method is one of the precision techniques and has an aim for clean technology in the transportation of the pure gas in the clean pipes. The magnetic abrasive polishing method is not so common in the field of machine that it is not known to widely. There are rarely researcher in this feilld because of non-effectiveness of magnetic abrasive. Therefore, in this paper we deals with the development of the magnetic abrasive with the fse of Sr-Ferrite. In this development, abrasive grain A has been made by using the resin bond fabricated at low temperature. And magnetic abrasive powder was fabricated from the Sr-Ferrite which was crushed into 200 mesh. The XRD analysis result shows that only A abrasive and Sr-Ferrite crystal peaks were detected, explaining that resin bond was not any more to contribute chemical reaction. From SEM analysis, we found that A abrasive and Sr-Ferrite were strongly bonding with each other.

• 환경위생공학
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• 제13권3호
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• pp.72-78
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• 1998

For investigation into gas permeation characteristics, the porous alumina membrane with asymmetrical structure, having upper layer with 10 nanometer under of pore diameter and lower layer with 36 nanometer of pore diameter, was prepared by anodic oxidation using DC power supply of constant current mode in an aqueous solution of sulfuric acid. The aluminium plate was pre-treated with thermal oxidation, chemical polishing and electrochemical polishing before anodic oxidation. Because the pore size depended upon the electrolyte, electrolyte concentration, temperature, current density, and so on, the the membranes were prepared by controling the current density, as a very low current density for upper layer of membrane and a high current density for lower layer of membrane. By control of current quantity, the thicknesses of upper layer of membranes were about $6{\;}{\mu}m$ and the total thicknesses of membranes were about $80-90{\;}{\mu}m$. We found that the mechanism of gas permeation depended on model of the Knudsen flow for the membrane prepared at each condition.

• Design & Manufacturing
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• 제2권4호
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• pp.44-47
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• 2008

The magnetic polishing is the useful method to finish some machinery fabrications by using magnetic power. This method is one of the precision techniques and has an aim for clean technology in the transportation of the pure gas in the clean pipes. The magnetic abrasive polishing method is not so common in the field of machine that it is not known to widely. There are rarely researcher in this field because of non-effectiveness of magnetic abrasive. Therefore, in this paper we deals with the development of the magnetic abrasive with the use of Sr-Ferrite. In this development, abrasive grain A has been made by using the resin bond fabricated at low temperature. And magnetic abrasive powder was fabricated from the Sr-Ferrite which was crushed into 200 mesh. The XRD analysis result shows that only A abrasive and Sr-Ferrite crystal peaks were detected, explaining that resin bond was not any more to contribute chemical reaction. From SEM analysis, we found that A abrasive and Sr-Ferrite were strongly bonding with each other.

• 반도체디스플레이기술학회지
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• 제6권3호
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• pp.1-6
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• 2007

The integrated thermal-chemical-mechanical (TCM) material removal model presented in the companion paper is dynamically simulated in this work. The model is applied to a Cu CMP process for the simulation and the results of the three individual ingredients composing the model are presented separately first. These results are then incorporated to calculate the total material removal rate (MRR) of the Cu CMP. It is shown that the non-linear trend of MRR with respect to the applied mechanical power (i.e., non-Prestonian behavior), which is not well explained with the models established in principle on conventional contact mechanics, may be due to the chemical reaction(s) varying non-linearly with the temperature in the wafer.

• 한국안전학회지
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• 제18권2호
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• pp.46-49
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• 2003

The magnetic polishing is the useful method to finish some machinery fabrications by using magnetic power. This method is one of the precision techniques and has m aim for clean technology in the transportation of the pure gas in the clean pipes. The magnetic abrasive polishing method is not so common in the field of machine that it is not known to widely. There are rarely researcher in this field because of non-effectiveness of magnetic abrasive. Therefore, in this paper we deals with the development of the magnetic abrasive with the use of Ba-Ferrite. In this development, abrasive grain WA has been made by using the min bond fabricated at low temperature. And magnetic abrasive powder was fabricated from the Ba-Ferrite which was crushed into 200 mesh. The XRD analysis result shows that only WA abrasive and Ba-Ferrite crystal peaks were detected, explaining that resin bond was not any more to contribute chemical reaction. From SEM analysis, we found that WA abrasive and Ba-Ferrite were strongly bonding with each other.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2003년도 학술대회논문집
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• pp.227-232
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• 2003

Anodizing film was prepared by anodic oxidation of pure aluminum(purity > 99.50) using DC power supply for constant current mode in an electrolytic solution of surface of sulfuric acid. Effects of pre-treatment process such as chemical polishing, acid cleaning, alkali etching before anodic oxidation, were studied to microstructures and surface morphologies. A roughness on surface of anodizing film had to be decreased for amorphous phase by anodic oxidation. A roughness on surface of anodizing film decrease as annealing temperature increased in chemical polishing.

• 열처리공학회지
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• 제34권2호
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• pp.75-80
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• 2021

The crystal grains of polycrystalline diamond vary depending on deposition conditions and growth thickness. The diamond thin film deposited by the CVD method has a very rough growth surface. On average, the surface roughness of a diamond thin film deposited by CVD is in the range of 1-100 um. However, the high surface roughness of diamond is unsuitable for application in industrial applications, so the surface roughness must be lowered. As the surface roughness decreases, the scattering of incident light is reduced, the heat conduction is improved, the mechanical surface friction coefficient can be lowered, and the transmittance can also be improved. In addition, diamond-coated cutting tools have the advantage of enabling ultra-precise machining. In this study, the surface roughness of diamond was improved by thermal diffusion reaction between diamond carbon atoms and ferrous metals at high temperature for diamond thin films deposited by MPCVD.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.236-236
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• 2008

(Bi,La)$Ti_3O_{12}$(BLT) thin film is one of the most attractive materials for ferroelectric random access memory (FRAM) applications due to its some excellent properties such as high fatigue endurance, low processing temperature, and large remanent polarization [1-2]. The authors firstly investigated and reported the damascene process of chemical mechanical polishing (CMP) for BLT thin film capacitor on behalf of plasma etching process for fabrication of FRAM [3]. CMP process could prepare the BLT capacitors with the superior process efficiency to the plasma etching process without the well-known problems such as plasma damages and sloped sidewall, which was enough to apply to the fabrication of FRAM [2]. BLT-CMP characteristics showed the typical oxide-CMP characteristics which were related in both pressure and velocity according to Preston's equation and Hernandez's power law [2-4]. Good surface roughness was also obtained for the densification of multilevel memory structure by CMP process [3]. The well prepared BLT capacitors fabricated by CMP process should have the sufficient ferroelectric properties for FRAM; therefore, in this study the electrical properties of the BLT capacitor fabricated by CMP process were analyzed with the process parameters. Especially, the effects of CMP pressure, which had mainly affected the removal rate of BLT thin films [2], on the electrical properties were investigated. In order to check the influences of the pressure in eMP process on the ferroelectric properties of BLT thin films, the electrical test of the BLT capacitors was performed. The polarization-voltage (P-V) characteristics show a decreased the remanent polarization (Pr) value when CMP process was performed with the high pressure. The shape of the hysteresis loop is close to typical loop of BLT thin films in case of the specimen after CMP process with the pressures of 4.9 kPa; however, the shape of the hysteresis loop is not saturated due to high leakage current caused by structural and/or chemical damages in case of the specimen after CMP process with the pressures of 29.4 kPa. The leakage current density obtained with positive bias is one order lower than that with negative bias in case of 29.4 kPa, which was one or two order higher than in case of 4.9 kPa. The high pressure condition was not suitable for the damascene process of BLT thin films due to the defects in electrical properties although the better efficiency of process. by higher removal rate of BLT thin films was obtained with the high pressure of 29.4 kPa in the previous study [2].

• 대한기계학회논문집A
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• 제25권12호
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• pp.1911-1918
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• 2001

Recently the non-destructive test technique which uses the grain boundary etching characteristics owing to the variation of material structures has been proposed. However, during in-serviced GEM test there are a lot of variables such as the changes of temperature and concentration of etching solution, the roughness condition of surface polished etc.. The purpose of this paper is to investigate the influences of these test variables on GEM test results in order to establish a reliable and sensitive of GEM evaluation technique. The experiments are conducted in various solution temperatures, 10$\^{C}$, 15$\^{C}$, 20$\^{C}$, and 25$\^{C}$ and in 70% and 100% concentrations of that, and in various surface roughnesses polished by #800, #2000, and 0.3㎛ alumina powder. Through the test with variables, it is verified that the decrease of temperature and concentration of etching solution and the coarsened surface roughness by not using polishing cloth and powder induce some badly and/or greatly influences on GEM test results like grain boundary etching width(W$\_$GB) and intersecting point ratio(N$\_$i/N$\_$0/). Therefore, to get reliable and good GEM test results, it must be prepared the surface of specimen polished by polishing cloth and 0.3㎛ alumina powder and the saturated picric acid solution having 25$\^{C}$ and be maintained the constant temperature(25$\^{C}$) during GEM test.

• 한국산학기술학회논문지
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• 제17권8호
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• pp.722-727
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• 2016

본 연구에서는 전류효율 향상을 통하여 전해연마 공정 중 발생하는 폐산 폐기물 발생량을 감소시키고자 하였다. 구형 부스바와 Taguchi 기법을 이용하여 전해연마 공정의 최적 조건을 도출하였다. 전해연마 공정 중 전류효율에 영향을 미치는 제어인자로 전류밀도, 전해연마 시간, 전해액 온도, 유량을 선택하였다. 각 제어인자에 대하여 3수준을 고려하여 직교 배열표를 작성하여 실험을 수행하였다. Taguchi 기법에 따라 망대특성 SN비를 산출한 결과 전류밀도가 가장 큰 영향을 미치고 전해연마 시간이 가장 적은 영향을 미치는 것을 확인하였다. 폐산 폐기물 발생량을 최소화할 수 있는 최적 조건은 전류밀도 $45A/dm^2$,전해연마 시간 4 min, 전해액 온도 $65^{\circ}C$, 유량 7 L/min였다. 분산분석 결과 전류밀도, 전해액 온도, 유량이 신뢰수준 95%에서 유의함을 확인하였다. 구형 부스바 사용으로 접촉 면적 및 접촉력 증가로 전류효율이 향상되어 폐산 폐기물 발생량을 감소시킬 수 있었다. 부스바의 형태(선 접점 부스바, 반구형 면 접점 부스바, 구형 면 접점 부스바)에 따른 전류효율의 영향과 관련한 비교 연구가 향후 진행될 예정이다.