• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.215-215
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• 2004

본 연구는 차세대 FPD의 소재로서 각광받고 있는 유기EL 의 제조공정을 위한 연구이다. 유기 EL 의 모재로서 이용되고 있는 ITO 코팅 유리는 그 표면의 정밀도에 따라서 제품의 불량률이 변화되게 됨으로 제조공정에 있어서는 매우 중요한 역할을 한다. 하지만, ITO 코팅유리의 표면 정밀도를 얻기 위하여 필수적인 연마공정 내에서 연마입자와 ITO 코팅유리의 상호작용에 의하여 연마가 이루어질 뿐 아니라, 불순물의 유입이나 기타 공정조건에 의하여 유리 표면 결함이 발생 및 불균일 연마가 수행되는 것은 피할수 없는 상황이다.(중략)

• Journal of the Korean Society for Precision Engineering
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• v.14 no.10
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• pp.58-67
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• 1997

Generally, die polishing process occupies about 30 .approx. 50% of the whole die manufacturing time. However, die polshing has not been automated yet, since it needs a great deal of experience and skill. This study aims at development of an expert system for die polishing which gives such optimal parameters as tool and polishing conditions. Through experiments, polishing characteristics such as surface roughness, stock removal and scratch were analyzed quantitatively for each polishing tool, and a knowledge base for the expert system was established. Evaluation tests show that the developed system works well to suggest the optimal polishing conditions and it is very promising.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.539-539
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• 2008

본 논문에서는 투명전도박막의 균일한 표면특성을 확보하기 위해 광역평탄화 공정을 적용하여 투명전도 박막의 표면 거칠기를 연구하였으며 슬러리의 종류에 따른 박막의 연마특성을 연구하였다. 본 실험에서 사용된 ITO 박막은 RF Sputtering에 의해 제작되었고 하부 기판은 석영 Glass가 사용되었다. 광역평탄화를 위한 CMP 공정은 고분자 물질계열의 패드위에 슬러리입자를 공급하고 웨이퍼 캐리어에 하중을 가하며 웨이퍼의 표면을 연마하는 방법으로 가공물을 탄성패드에 누르면서 상대 운동시켜 가공물과 친화력이 우수한 부식액으로 화학적 제거를 함과 동시에 초미립자로 기계적 제거를 하는 것이다. ITO 박막의 평탄화를 위한 공정조건은 Polisher pressure 300 g/$cm^2$, 슬러리 유속 80 ml/min, 플레이튼속도 60 rpm으로 하였다. 위의 조건에 따라 공정을 진행 후 연마특성을 측정하였으며 이때 사용된 슬러리는 산화막에 사용되는 실리카슬러리와 금속연마용 슬러리인 EPL을 사용하였다. 연마율은 실리카 슬러리가 EPL슬러리에 비해 높음을 확인 하였다. CMP 공정에 의해 평탄화를 수행 할 경우 실리카슬러리와 EPL슬러리 모두 CMP전에 비해 돌출된 힐록들이 감소되었음을 알 수 있었다. 비균일도 특성은 모든 슬러리가 양호한 특성을 나타내었다. 평탄화된 박막의 표면과 거칠기 특성은 AFM(XE-200, PSIA Company) 을 이용하여 분석을 하였다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.6
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• pp.763-778
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• 2019

Abrasive waterjet cutting technology has been used for rock excavation of tunnels and underground structures due to various advantages. In order to cut rocks by using the abrasive waterjet system, abrasive is essential to enhance impact energies for fracturing the target rock. Since garnet abrasives are not produced in Korea, alternative abrasives, instead of garnets, are needed to achieve the economical waterjet cutting. This study is to analyze cutting performance for rocks with sandy particles as alternative abrasive. Cutting tests were carried out on granite specimens at the constant waterjet energy (e.g., water pressure or water flow rate). The five kinds of sands, sampled by construction fields and natural sites, were prepared to perform the experimental tests. When sea sand was used as an alternative abrasive, cutting performance was secured to be 60~70% compared to the commercial garnet abrasive. Thus, it is expected that sand abrasives can be applied on the waterjet cutting process for the economical excavation construction.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.2
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• pp.141-151
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• 2015

A new rock excavation method using an abrasive injection waterjet system has been developed to enhance the efficiency and reduce the vibration of tunnel excavation. The abrasive feed rate is an important factor for the cutting performance and the economical efficiency of waterjet-based excavation. In this study, various experiments were performed to explore the effects of major process parameters for both the abrasive feed rate and the suction pressure occurring inside the mixing chamber when the abrasives are inhaled. Experimental results reveal that the abrasive feed rate is affected by geometry parameters (abrasive pipe height, length, and tortuosity), abrasive parameters (abrasive particle size), and jet energy parameters (water pressure and water flow rate). In addition, the relation between the cutting performance and the abrasive feed rate was discussed on the basis of the results of an experimental study. The cutting performance can be maximized when the abrasive feed rate is controlled appropriately via careful management of major process parameters.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1289-1293
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• 2005

We will improve tools performance without the change of a tools' physical shape, if we process mirror like finishing on the surface of cutting tools. Because cutting tools' shapes are very complex, the general method of polishing can't be polished. So we will apply new method of polishing which is magnetic fluid grinding technique. Magnetic fluid grinding technique can polish complex shape's workpiece by pressing the surface of workpiece with magnetic and abrasive grains in magnetic field. Therefore we developed the polishing equipment to improve the performance of cutting tools and experimented on various polishing conditions to determine the polishing conditions of cutting tools.

• Journal of the Korean Ceramic Society
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• v.40 no.2
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• pp.167-171
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• 2003

CMP(Chemical Mechanical Planarization) slurry for STI process is made by mechanically synthesized$CeO_2$as abrasive. The abrasive can be stabilized by electrostatic or steric stabilization in aqueous slurry and steric stabilization is more effective for long-term stability. Blanket-type$SiO_2$and $Si_3N_4$ wafers are polished with CMP slurry containing$CeO_2$synthesized in 50$0^{\circ}C$ or $700^{\circ}C$. Removal rate and surface uniformity of$SiO_2$and$Si_3N_4$wafer and selectivity are influenced by synthetic condition of abrasive, suspension stability and pH of slurries.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.541-541
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• 2008

반도체 소자가 차세대 초미세 공정 기술 도입의 가속화를 통해 고속화 및 고집적화 되어 감에 따라 나노(Nano) 크기의 회로 선폭 미세화를 극복하고자 최적의 CMP (Chemical Mechanical Polishing) 공정이 요구되어지고 있다. 이처럼 CMP 공정이 반도체 제조 공정에 적용됨으로써 공정 마진 확보에 진일보 하였으나 CMP 장비의 공정 조건, 슬러리의 종류, 연마패드의 종류 등에 의해 CMP 성능이 결정된다. 특히 슬러리는 연마 공정의 성능에 중요한 영향을 미치는 요인이다. 고가의 슬러리가 차지하는 비중이 40% 이상을 넘고 있어 슬러리 원액의 소모량을 줄이기 위한 연구들이 현재 활발히 진행되고 있다. 본 연구에서는 새로운 연마제의 특성을 알아보기 위해 탈이온수(De-ionized water; DIW) 에 $CeO_2$, 연마제를 첨가한 후 분산시간에 따른 연마 특성과 AFM, EDX, XRD, TEM분석을 통해 그 가능성을 알아보았다.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.31-42
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• 2014

Purpose: The present study was conducted to investigate the effect of the physical properties of RGP lens induced by lens polishing on the actual wearer's subjective comfort, the tear film break-up time and the blinking rate as a follow-up study that revealed the relationship between the lens physical properties during lens manufacturing and lens wearer's factors. Methods: RGP lenses made from the three different polishing conditions (25, 50 and 100 seconds) were applied on 28 eyes of 17 subjects, aged 20 to 29 years, without any known disease and surgical history in the eyes. While the subjects were asked to wear the RGP lenses longer than a week, the questionnaire for the comfortability was administered everyday. Subjective and objective tear break-up time and blinking rate of the wearers were further measured. Results: The wearer's subjective comfortability showed some difference in the type of discomfort and satisfaction score according to the polishing status when wearing RGP lenses made from different polishing conditions longer than a week, and a bigger difference in satisfaction score induced by polishing condition was especially shown in experienced RGP lens wearer rather than un-experienced wearer. In the case of RGP lens wearer compared with the ones without the wearing experience, as the wearing time increased subjective and objective tear break-up time were increased and the blinking rate was decreased. However, subjective and objective tear break-up time were tended to decrease with even longer wearing time when wearing the RGP lens made from the polishment for 100 seconds. Conclusions: These results confirmed that the optimization of physical properties of the lens may not give the same effect on the wearer's subjective and objective symptoms and other factors when actual wearing. From the results, it can suggest that the success rate of RGP lens wear may be changed by physiological factors such as the stabilization of wearer's tear film, comfortability and lens wearing experience when wearing RGP lens based on 'The manufacturing standard for soft contact lens/hard contact lens' provided by Korea Food and Drug Administration.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.779-784
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• 2011

This study was carried out on the crack healing of three types of SiC ceramics based on a $SiO_2$ additive, taking into account the roughness of the polishing plate used for polishing the specimens. The mixtures were subsequently hot-pressed in $N_2$ gas for one hour under 35 MPa at 2053 K. In these specimens, the optimized crack-healing condition was 1373 K for one hour in air. The crack-healing material of the cracked part was the glassy phase of $SiO_2$ that was formed by the oxidation of SiC. In the optimum healing condition, the bending strength of non-polished SiC ceramics was not completely recovered. However, the bending strength of the SAY specimen was excellent, considering the economic aspects of SAY, SAYS-1, and SAYS-2. The SAY specimen is definitely superior to the others after an hour of heat treatment. There was a decrease in the number and size of defects in the specimen polished by using a $125-{\mu}m$ polishing plate; however, the micro-surface defects were not completely repaired. The specimen polished by using a 40-${\mu}m$ polishing plate showed little voids or surface defects after an hour of heat treatment. The bending strength of the specimen mirror-polished by using a 6-${\mu}m$ polishing plate was completely recovered.