가공속도와 슬러리의 가공온도에 따른 웨이퍼 폴리싱의 표면특성에 관한 연구

이정택,원종구,신태희,이은상 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-

Silicon wafers which are the starting materials for the industry of semiconductor must be very flat in order to print circuits on them by lithographic processes. Therefore, the wafer polishing is an essential process used in the fabrication of silicon wafers to achieve a globally planar and mirror-like wafer surface. The surface roughness in the wafer depends on the surface properties of the carrier head unit along with other machining conditions such as polishing pad, Processing velocity, machining temperature, down-force distribution and so on. Also the applied down-force is an important parameter of polishing process. This study shows the surface characteristics between the polishing pad and the wafer carrier unit by wafer polishing system head. The experiments were performed to observe the down-force and temperature when the wafer carrier head unit was pressed down onto the polishing pad. To measure the down-force distribution in processing velocity, the experimental set up used the loadcell to get the signal of the applied pressure against the polishing pad in actual processing with detecting temperature in slurry. Thus the optimum condition selection of ultra precision wafer polishing is using loadcell and infrared temperature sensor. The optimum condition is selected to use a result data that measure a pressure in processing velocity. By using optimum condition, it helps to achieve an ultra precision mirror like surface.

웨이퍼 폴리싱의 가공 조건에 따른 표면 특성에 관한 연구

이정택,원종구,이은상 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

The wafer polishing is an essential process used in the fabrication of silicon wafers to achieve a globally planar and mirror-like wafer surface. The surface roughness in the wafer depends on the surface properties of the carrier head unit along with other machining conditions such as polishing pad, working speed, temperature, down-force and ETC. Also the applied down-force is an important parameter of polishing process. This study shows the surface characteristics between the polishing pad and the wafer carrier unit by wafer polishing system head. The experiments were performed to observe the down-force and temperature when the wafer carrier head unit was pressed down onto the polishing pad. To measure the down-force distribution, the experimental set up used the loadcell to get the signal of the applied pressure against the polishing pad in actual processing with detecting temperature using IR temperature sensor.

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.

활배근 근피판을 이용한 노출된 Cardiac Pacemaker의 치험예 -Case Report-

신영진,이택종,전은석 大韓成形外科學會 1989 Archives of Plastic Surgery Vol.16 No.6

Pacemaker was first achived by Chardack et al. in 1960. The principal indications are the complete heart block, congestive heart failure during complete heart block, and bradycardias ?? tachycardias in which drugs are ineffectual. Exposure of the implanted pulse generator due to infection or pressure necrosis is common. The usual methods of dealing with this complication are wound irrigatons with antibiotic solutions, wound resuture or re-implantation of the pulse generator at another site, and local flap with skin graft. We experienced a case of recurrent skin ulcerations with local infection overlying the pacemader. A Latissimus Dorsi myocutaneous flap was used successfully to provide soft tissue coverage of the exposed pacemaker and the patient was tolerable to the mild twitching of the lastissimus dorsi muscle. The myocutaneous flap was great value in reconstructing problem wounds because of their rich vascular supply and superior resistance to infection.

강구조 부재의 불 비례 - 반복 하중 하의 소성거동

김주헌(Ju Hun Kim),이은택(Eun Taik Lee),김덕재(Duck Jae Kim) 한국강구조학회 1995 韓國鋼構造學會誌 Vol.7 No.2

Based on the existence of a yield surface and a bound surface which represents the maximum stress state the material ever experienced, a plasticity model is modified to describe the behaviour of metal under nonproportional loadings. This paper is concered with the improvement of a plasticity model of the two surface type for structural steel based on experimentally observed features of 304 stainless steel specimens tested under axial torsional cyclic nonproportional loading condition at room temperature performed by Medowell. The proposed model is verified through an experimental program that includes different combinations of nonproportionally applied forces performed by Lee.

A feasibility study of a pH sensitive nanomedicine using doxorubicin loaded poly(aspartic acid-graft-imidazole)-block-poly(ethylene glycol) micelles

Lee, Eun Seong,Kim, Ji Hoon,Sim, Taehoon,Youn, Yu Seok,Lee, Beom-Jin,Oh, Young Taik,Oh, Kyung Taek The Royal Society of Chemistry 2014 Journal of Materials Chemistry B Vol.2 No.9

Exposure assessment of workers in printed electronics workplace

Lee, Ji Hyun,Sohn, Eun Kyung,Ahn, Jin Soo,Ahn, Kangho,Kim, Keun Soo,Lee, Jong Hwan,Lee, Taik Min,Yu, Il Je Informa Healthcare USA, Inc. 2013 Inhalation toxicology Vol.25 No.8

<P>Printed electronics uses converging technologies, such as printing, fine mechanics, nanotechnology, electronics and other new technologies. Consequently, printed electronics raises additional health and safety concerns to those experienced in the traditional printing industry. This study investigated two printed electronics workplaces based on a walk-through survey and personal and area sampling. All the printed electronics operations were conducted in a cleanroom. No indication of exposure to excess silver nanoparticles or carbon nanotubes (CNTs) was found. While the organic solvents were lower than current occupational exposure limits, there was a lack of engineering controls, such as local exhaust ventilation, correct enclosure and duct connections. There was also an insufficient quantity of personal protective equipment, and some organic solvents not described in the safety data sheets (SDSs) were detected in the air samples. Plus, the cleaning work, a major emissions operation, was not conducted within a hood, and the cleaning waste was not properly disposed of. Therefore, the present exposure assessment results from two printed electronics workplaces suggest that the printed electronics industry needs to take note of the occupational safety and health risks and hazards already established by the traditional printing industry, along with new risks and hazards originating from converging technologies such as nanotechnology.</P>

Damage Detection Using Measurement Response Data of Beam Structure Subject to a Moving Mass

Lee, Eun-Taik,Eun, Hee-Chang SciELO 2015 Latin american journal of solids and structures Vol.12 No.12

대퇴골 과상부 및 과간 골절 불유합의 치료

이성종,이석하,이동기,유연식,심재익,김택선,이덕용,이은노,김윤엽 대한골절학회 1999 대한골절학회지 Vol.12 No.4

The femoral supracondylar and intercondylar fractures are difficult to be treated due to severe soft tissue damage, comminution, intraarticular extension of fracture and injury to the quadriceps mechanism frequently. The causes of nonunion are inadequate anatomical reduction, fixation failure, bone defect and infection occasionally, which is difficult to be treated. The authors analyzed 16 cases with nonunion of femoral supracondylar and intercondylar fracture who had been treated surgically from January 1990 to December 1997. According to AO/ASIF classification in the initial fracture patterns, type A were 8 cases, type B was 1 case and type C were 7 cases. The duration between initial treatment and surgical treatment of nonunion was 6 months in average. The causes of nonunion were fixation failure due to inadequate device selection in 9 cases, inadequate anatomical reduction or surgical technique in 4 cases and infection in 3 cases. The treatments were internal fixation with Dynamic condylar screw(DCS) in 9 cases, internal fixation with condylar blade plate in 4 cases, monofocal lenghtening with Ilizarov in 1 case and bifocal lenghtening with Ilizarov in 2 cases. According to Schatzker classification, the good result was obtained in 11 cases(68.8%). The complications were 3 knee joint ankyloses, 2 superficial wound infections, 1 delayed union and 1 deep vein thrombosis. In conclusion, the requirement for the good result in treatment of nonunion are exact anatomical reduction, rigid fixation and autogenous bone graft.

Estimation of parameter matrices based on measured data

Lee, Eun-Taik,Rahmatalla, Salam,Eun, Hee-Chang Elsevier 2011 Applied mathematical modelling Vol.35 No.10

<P><B>Abstract</B></P><P>Finite element structural updating based on measured data may inherent significant errors due to uncertainties in the updated physical parameter matrices. This study presents analytical equations to estimate the change in the physical parameter matrices based on the measured modal data of dynamic systems and the measured displacement data of static systems. The equations for the parameter estimation are derived by minimizing cost functions in the satisfaction of the eigenvalue equation, the mode shape orthogonality requirements for the dynamic system, and the satisfaction of the measured displacement data for the static systems. The proposed method utilizes the Moore–Penrose inverse for the inverse of the rectangular matrices without using Lagrange multipliers. Comparing the analytical results with Berman & Nagy’s method and Yang & Chen’s method, this study demonstrates that the derived equations take simpler forms and produce more accurate results. The proposed method can be widely utilized in predicting static or dynamic parameter matrices for the design and analysis of any structure.</P>