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Evaluation of Y2O3 surface machinability using ultra-precision lapping process with IED
차지완,황성철,이은상 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.4
Prospects of Y2O3 have been more extended as a great promising and creditable material for optical, electronic and mechanical purposes. Y2O3 has been more observed as a fine ceramic which has great material properties: high light transparency, excellent thermal resistance and chemical inertness. But in terms of effective application of Y2O3, its hard and brittle nature needs to be overcome during the surface machining process. Therefore, the surface machining control of Y2O3 should be conducted carefully. The evaluation for stable and continuous machining should also be investigated in various industrial fields as there are only limited studies on the subject. The lapping process with in-process electrolytic dressing (IED) is widely used for surface machining of hard and brittle materials. In this study, Y2O3 surface machinability was evaluated by using the ultra-precision lapping process with IED method by changing three major variables: applied force, wheel speed and machining time. The most suitable value of Ra 92nm surface roughness was acquired with smooth surface quality from the following machining condition: 7kg of applied force, 60rpm of wheel speed and 30minutes of machining time. After the lapping process, the machining tendency and surface characteristics were analyzed with fracture toughness and Vickers hardness for the evaluation of Y2O3 surface machinability.
실리콘 웨이퍼 폴리싱 패드의 수명과 드레싱 결함의 관계에 관한 연구
차지완,이은상 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-
Polishing process of Si wafer is a momentous stage during the semiconductor process of manufacture. A surface condition of fabricated Si wafer influences in inferiority rate of final semiconductor products. Among the major factors of wafer polishing process, polishing pad surface roughness and a degree of plastic deformation have an effect of polished wafer surface quality. A pad should be maintained its machining ability during the polishing process. However, capability of pad is reduced when polishing time is increased. Dressing and conditioning process on a polishing pad is needed for the preservation of pad surface condition. In this study, an influence of dressing defect was investigated during the Si wafer polishing process. When the dressing process was not supplied, pad surface quality was analyzed by using SEM images, pad surface roughness variation and temperature variation on the polishing pad. And the relationship between Si wafer polishing pad lifetime and dressing defect was evaluated.
이트리아($Y_2O_3$) 세라믹 래핑가공의 AE 신호 분석
차지완,황성철,신태희,이은상,Cha, Ji-Wan,Hwang, Sung-Chul,Shin, Tae-Hee,Lee, Eun-Sang 한국생산제조학회 2010 한국생산제조학회지 Vol.25 No.3
AE(acoustic emission) sensor has been used for a state monitoring and observation during a ultra-precision machining because AE signal, which has high frequency range, is sensitive enough. In case of ceramic fabrication, a monitoring of machining state is important because of its hard and brittle nature. A machining characteristic of ceramic is susceptibly different in accordance with variable machining conditions. In this study, Yttria($Y_2O_3$) ceramic was fabricated using the ultra-precision lapping process with in-process electrolytic dressing(IED) method. And the surface machining characteristic and AE sensor signal were compared and analyzed.
차지완(Ji-Wan Cha),신태희(Tae-Hee Shin),이은상(Eun-Sang Lee) 한국생산제조학회 2009 한국공작기계학회 추계학술대회논문집 Vol.2009 No.-
AE (Acoustic Emission) sensor applications during Si wafer polishing process are various: monitoring of polishing pad state, change of slurry characteristics, friction-wear between wafer and polishing pad and identification of detail polishing process stage. AE sensor is suitable for monitoring of sensitive machining characteristics. Wafer polishing process is a detail and sensitive material removal process with actions among polishing pad, slurry, water, applied pressure and rotation speed. In this study, Elastic waves were detected during a wafer polishing process in accordance with polishing pad deformation conditions by using AE sensor. And polishing pad deformation and state of wafer polishing process were monitored and analyzed.
차지완(Ji-Wan Cha),황성철(Sung-Chul Hwang),신태희(Tae-Hee Shin),이은상(Eun-Sang Lee) 한국생산제조학회 2010 한국생산제조학회지 Vol.19 No.1
AE(acoustic emission) sensor has been used for a state monitoring and observation during a ultra-precision machining because AE signal, which has high frequency range, is sensitive enough. In case of ceramic fabrication, a monitoring of machining state is important because of its hard and brittle nature. A machining characteristic of ceramic is susceptibly different in accordance with variable machining conditions. In this study, Yttria(Y₂O₃) ceramic was fabricated using the ultra-precision lapping process with in-process electrolytic dressing(IED) method. And the surface machining characteristic and AE sensor signal were compared and analyzed.
신경 회로망을 이용한 Wafer final polishing의 가공 결과 예측
황성철,차지완,이은상 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-
Polishing is one of the important processing having influence on the surface roughness in manufacturing of Si-wafers. The surface roughness in wafer polishing is mainly affected by the many process parameters. A feed forward neural network model is developed exploiting experimental measurements from the surface in wafer final polishing. The input variables of Neural Network model are process parameters. The output variables are measured surface roughness. The neural network model is trained and performed by MATLAB. The model can be used for the analysis and prediction of the complex relationship. From this, it is clearly seen that a good agreement is observed between the predicted values and experimental measurement values.
연속전해드레싱을 적용한 래핑을 이용한 Y₂O₃가공특성에 대한 연구
황성철,차지완,이은상 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-
Recently, application of ceramics has increased gradually due to excellent mechanical properties. Y₂O₃ has been more observed as a fine ceramics having great material properties; high light transparency, excellent thermal resistance and chemical inertness. Therefore prospects of Y₂O₃ have been more extended as a great promising material for optical, electronic and mechanical purpose. But for the effective application of Y₂O₃, it is need to overcome the imperfection of hard and brittle nature during machining process. Accordingly, the machining control of Y₂O₃ should be conducted and the evaluation for the stable and continuous machining should be investigated in various industrial fields. In this study, theevaluation of Y₂O₃ machinability was conducted using the ultra-precision lapping process with In-process Electrolytic Dressing.
신태희(Tae-Hee Shin),차지완(Ji-Wan Cha),이은상(Eun-sang Lee) 한국생산제조학회 2009 한국공작기계학회 추계학술대회논문집 Vol.2009 No.-
The condition of materials that could be applied to the high-technology industry is required to a high-strength as well as a light weight. With the increasing demand for these conditions, magnesium alloy, one of the lightweight materials, is raising on the world. Magnesium alloy are not only being applied to the electronic equipment such as a frame of cellular phone and laptop computer, but also extending to the vehicle industry and the aero-space industry. This applications of the magnesium alloy are made of the die-casting process due to the production on a large scale. However, this process makes too many microscopic burr. So, for the removal of microscopic burrs on the magnesium alloy, electrochemical deburring process is suggested and its conditions are researched in this paper.
Wafer final polishing에 따른 표면 현상과 마멸도에 관한 연구
원종구,이정택,황성철,차지완,이은상 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-
In recent years, developments in the semiconductor and electronic industries have brought a rapid increase in the use of silicon wafer. For further improvement of the ultra precision surface and flatness of Si wafer necessary to high density ULSI, it is known that final polishing is very important. Polishing one of the important methods in manufacturing of Si wafers and in thinning of completed device wafers. This study will report the evaluation on abrasion of wafer according to variety processing condition, which have major influence on the abrasion and surface defect of Si wafer polishing, were adapted to polishing pressure, machining speed, and the slurry mix ratio. Thus the optimum condition selection of ultra precision Si wafer polishing using load cell and infrared temperature sensor. To evaluate each machining factor, use a data through each sensor. That evaluation of abrasion according to variety condition is selected to use a result data that measure a pressure, machining speed, and the processing time. And optimum condition is selected by this result. By using optimum condition, it achieve a ultra precision mirror like surface.