• 한국생산제조학회지
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• 제20권5호
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• pp.517-522
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• 2011

Most of SEM is double condenser lens system. Two condenser lenses are required to provide the high demagnification ratios necessary for forming nanometer probes. The thin lens concept provides a highly useful basis for preliminary calculations in a broad range of situations. It is an easy way to understand the electron beam paths in column. Demagnification is easily calculated by this method. In this paper, we present design processes for condenser lens's demagnification by using thin lens combination model. Also, we verify the reliability of our design processes by comparing the modeled demagnification with these of corrected condenser lens.

• 대한전자공학회논문지SD
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• 제41권5호
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• pp.23-36
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• 2004

밀리미터파 대역용 고속 HEMT 소자 제작 및 개발을 위하여 0.l㎛ 이하의 T-게이트 길이를 형성하기 위한 전자빔 리소그래피 공정을 분석할 수 있는 새로운 몬테 카를로 시뮬레이터를 개발하였다. 전자빔에 의한 노광 공정 모델링을 위해 전자산란에 대한 몬데 카를로 시뮬레이션에서 다층 리지스트 및 다원자 타겟 기판 구조에서 리지스트에 전이되는 에너지를 효율적으로 계산하도록 내부 쉘 전자 산란과 에너지 손실에 대해 새로이 모델링하였다. 다층 리지스트 구조에서 T-게이트 형상을 얻기 위해서 보통은 재현성 문제로 각 리지스트에 대해 각기 다른 현상액을 사용하게 되는데, 3층 리지스트 구조에서의 전자빔 리소그래피 공정을 정확하게 시뮬레이션하기 위해 각기 다른 현상 모델을 적용하였다. 본 논문에서 제안 개발된 모델을 사용하여 HEMT 소자의 전자빔 리소그래피에 의한 0.l㎛ T-게이트 형성 공정을 시뮬레이션하고 SEM 측정 결과와 비교하여 T-게이트 형성 공정을 분석하였다.

• 대한방사선기술학회지:방사선기술과학
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• 제33권4호
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• pp.387-394
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• 2010

보건의료 분야에서 방사선은 의료기기 등의 멸균을 목적으로 빠르게 기존 방법을 대체하고 있으며 국제적으로, 정립된 엄격한 품질기준을 적용하고 있다. 방사선 멸균의 품질관리는 조사된 제품의 흡수선량이 요구 조건 및 기준에 부합하고 있음을 보증하는 것인데, $Co^{60}$ 동위원소를 이용하는 감마선 조사와는 달리 기계 전기적 방법에 따른 전자빔 조사는 더욱 많은 공정인자에 대해 기술적인 접근 방법이 필요하다. 국내에서는 2000년대 초반부터 전자빔 가속기의 보급이 시작되어 연구 및 산업분야에 이용되고 있으나 국제적 품질체계에 부합한 흡수선량의 품질에 관련된 연구는 매우 미흡한 실정이다. 서울방사선서비스는 2008년 10 MeV, 8 kW 사양의 대단위 전자빔 조사시설을 설치, 운영하기 시작하였는데, 전자빔 가속기, 제품운송장치, 안전장치, 기록관리 및 하위 구성장치가 통합시스템을 구성하여 우수제조기준에서 요구하는 공정품질 및 제품추적이 가능하도록 설계되었다. EN ISO11137로 대표되는 국제 표준의 이행을 위해서는 표준이 의도하는 바를 정확히 이해하고 장치의 설계기준부터 운영단계 별로 요구되는 품질시험을 정해진 절차 및 기준에 부합하도록 수행하여야 한다. 본 연구에 사용된 조사시설의 설계 시방을 제시하고 이를 구현하는데 필요한 핵심 장치의 설계 기준 및 특징에 대해 소개하였다. 또한 흡수선량 품질보증이라는 목적을 달성하기 위해 다양한 공정인자에 대한 품질시험결과를 제시하고 제시된 기준과 비교, 평가하였다.

• 한국표면공학회지
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• 제50권6호
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• pp.465-472
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• 2017

The ingot fabrication conditions related with the thermal shock bearing phase and microstructure have investigated for the rare earth zirconate ceramic material, lanthanum gadolinium zirconate, as a thermal barrier coating using electron beam evaporation method. The thermal shock resistance of the prepared ingot was evaluated by high energy electron beam irradiation. The rare earth zirconate ceramic powder was prepared by controlling the raw material powder composition of $La_2O_3$, $Gd_2O_3$ and $ZrO_2$ so as to have a composition of $(La_{0.3}Gd_{0.7})_2Zr_2O_7$ which was selected from the former study. Ingot samples were prepared under two conditions. The first condition is prepared by sintering the prepared powder mixture to form an ingot. The second condition is prepared by calcining the prepared powder mixture to form a composite phase and then sintering to form an ingot. X-ray diffraction(XRD) and Scanning Electron Microscope(SEM) were used to analyze phase forming behavior and microstructure of ingot samples. Nanoindentation method used to obtain elastic modulus and hardness of each ingot specimen. Also the stress distribution of ingot was simulated by using FEM method assuming the ingot surface was exposed to electron beam. As a results, in the case of an ingot having a network-shaped microstructure in which relatively coarse pores are included, it seems that the thermal shock resistance was higher than in the case of an ingot having a microstructure composed of relatively fine grains only or particles with the similar level size when the high energy electron beam irradiation.

• 한국생산제조학회지
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• 제24권3호
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• pp.270-277
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• 2015

In this paper, we describe the production of a specific electrostatic-type scanning electron microscope based on miniaturization for application in other types of vacuum equipment. The initial configuration of the SEM starts with a minimal configuration that allows people to view sample images. After improving the stability of the SEM operation and resolution, we conducted experiments on identifying the characteristics and development of an einzel-type condenser lens with reference to the demagnification lens system of an SEM. The experiments were conducted at an acceleration voltage of 5 kV and we found the shape of the lens to be more reliable than a conventional lens. The lens was then added to improve the resolution in the nanometer region. The current measured on the sample was approximately 40 pA and its magnification was 4,000 times.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1673-1675
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• 2006

As the manufacturing capacity needs for large size LCD TV shifts very fast into next generation, processing and test equipment makers face more difficult challenges in accommodating productivity, reliability and lead time of panel makers as well as the prerequisite of high process quality. In this paper, AKT will discuss its new innovative productivity solutions in PECVD (Plasma Enhanced Chemical Vapor Deposition), as the key thin film process system, and EBT (Electron Beam Test), as the key array test system, for the huge glass size with surface dimension larger than 2 meter by 2 meter.

• Journal of Welding and Joining
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• 제34권4호
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• pp.1-8
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• 2016

Metal AM(Additive Manufacturing) has been steadily developed and that is classified into two method. PBF(Powder Bed Fusion) deposited in the bed by the laser or electron beam as a heat source of the powder material and DED(Directed Energy Deposition) deposited by varied heat source of powder and solid filler material. In the developed countries has been applying high productivity process of solid filler metal based DED method to the aerospace and defense sectors. The price of the powder material is quite expensive compared to the solid filler metal. A study on DED method that is based on a solid filler metal is increasing significantly although was low accuracy and degree of freedom.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2010년도 춘계학술발표대회 초록집
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• pp.43-46
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• 2010

As the nuclear power plant has been constructed continuously for several decades in Korea, the welding technology for components manufacturing and installation has been improved largely. Standardization for weld test and qualification was also established systematically according to the concerned code. The welding for the main components requires the high reliability to keep the constant quality level, which means the repeatability of weld quality. Therefore the weld process qualified by thorough test and evaluation is able to be applied for manufacturing. Narrow gap SAW and GTAW process are usually applied for girth seam welding of pressure vessel like Reactor vessel, steam generator, and etc. For the surface cladding with stainless steel and Inconel material, strip welding process is mainly used. Inside cladding of nozzles is additionally applied with Hot wire GTAW and semi-auto welding process. Especially the weld joint having elliptical weld line on curved surface needs a specialized weld system which is automatically rotating with adjusting position of the head torch. The small sized pipe, tube, and internal parts of reactor vessel requests precise weld processes like an automatic GTAW and electron beam welding. Welding of dissimilar materials including Inconel690 material has high possibility of weld defects like a lack of fusion, various types of crack. To avoid these kinds of problem, optimum weld parameters and sequence should be set up through the many tests. As the life extension of nuclear power plant is general trend, weld technologies having higher reliability is required gradually. More development of specialized welding systems, weld part analysis and evaluation, and life prediction for main components should be taken into a consideration extensively.

• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.29-37
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• 2021

A 7 nm technology node using extreme ultraviolet lithography with a wavelength of 13.5 nm has been recently developed and applied to the semiconductor manufacturing process. Furthermore, the development of sub-3 nm technology nodes continues to be required. In this study, design factors of an electrostatic deflector for an ultra-miniaturized microcolumn system that can realize an electron wavelength of below 1.23 nm with an acceleration voltage of above 1 eV were investigated using a three-dimensional simulator. Particularly, the optimal design of the electrostatic octupole floating deflector was derived by optimizing the design elements and improving the driving method of the 1 keV low energy ultra-miniaturized microcolumn deflector. As a result, the entire wide field of view greater than 330 ㎛ at a working distance of 4 mm was realized with an ultra-high-resolution electron beam spot smaller than 10 nm. The results of this study are expected to be a basis technology for realizing a wafer-scale multi-array microcolumn system, which is expected to innovatively improve the throughput per unit time, which is the biggest drawback of electron beam lithography.

• International Journal of Precision Engineering and Manufacturing
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• 제7권4호
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• pp.14-17
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• 2006

A thin GaN semiconducting film that grows on sapphires due to metalorganic chemical vapor deposition was machined for nanophotonic applications. The thin film had multilayered superlattice structures, including nanoscaled InGaN layers. Eight alternating InGaN/GaN multilayers provided a blue light emission source. Nanoscaled holes, 150 nm in diameter, were patterned on polymethylmethacrylate (PMMA) film using an electron beam lithography system. The PMMA film blocked the etching species. Air holes, 75 nm in diameter, which acted as blue light diffraction sources, were etched on the top GaN layer by an inductively coupled plasma etcher. Hexagonal lattice photonic crystals were fabricated with 230-, 460-, 690-, and 920-nm pitches. The 450-nm wavelength blue light provided the nanodiffraction destructive and constructive interferences phenomena, which were dependent on the pitch of the holes.