• Title, Summary, Keyword: electron lens

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Hardware Design for the Control Signal Generation of Electron Optic by Focal Length (Focal length에 의한 전자 렌즈의 제어 신호 생성을 위한 하드웨어 설계)

  • Lim, Sun-Jong;Lee, Chan-Hong
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.5
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    • pp.96-100
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    • 2007
  • Condenser lens and objective lens are used to demagnify the image of the crossover to the final spot size. In lens, electrons are focused by magnetic fields. This fields is fringing field. It is important in electron focusing. Electron focusing occurs the radial component field and axial component field. Radial component produces rotational force and axial component produces radial force. Radial force causes the electron's trajectory to curve toward the optic axis and corss it. Focal length decreases as the current of lens increases. In this paper, we use the focal length for desiging the hardware of lens current control and present the results.

Realization for Each Element for capturing image in Scanning Electron Microscopy (주사 전자 현미경에서 영상 획득에 필요한 구성 요소 구현)

  • Lim, Sun-Jong;Lee, Chan-Hong
    • Journal of Korean Society of Laser Processing
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    • v.12 no.2
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    • pp.26-30
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    • 2009
  • Scanning Electron Microscopy (SEM) includes high voltage generator, electron gun, column, secondary electron detector, scan coil system and image grabber. Column includes electron lenses (condenser lens and objective lens). Condenser lens generates fringe field, makes focal length and control spot size. Focal length represents property of lens. Objective lens control focus. Most of the electrons emitted from the filament, are captured by the anode. The portion of the electron current that leaves the gun through the hole in the anode is called the beam current. Electron beam probe is called the focused beam on the specimen. Because of the lens and aperture, the probe current becomes smaller than the beam current. It generate various signals(backscattered electron, secondary electron) in an interaction with the specimen atoms. In this paper, we describe the result of research to develop the core elements for low-resolution SEM.

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Design and Analysis of an Objective Lens for a Scanning Electron Microscope by Coupling FE Analysis and Ray Tracing (유한요소해석과 광선추적을 연계한 주사전자 현미경 대물렌즈의 설계 및 해석)

  • Park, Keun;Lee, Jae-Jin;Park, Man-Jin;Kim, Dong-Hwan;Jang, Dong-Young
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.11
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    • pp.92-98
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    • 2009
  • The scanning electron microscope (SEM) contains an electron optical system in which electrons are emitted and moved to form a focused beam, and generates secondary electrons from the specimen surfaces, eventually making an image. The electron optical system usually contains two condenser lenses and an objective lens. The condenser lenses generate a magnetic field that forces the electron beams to form crossovers at desired locations. The objective lens then focuses the electron beams on the specimen. The present study covers the design and analysis of an objective lens for a thermionic SEM. A finite element (FE) analysis for the objective lens is performed to analyze its magnetic characteristics for various lens designs. Relevant beam trajectories are also investigated by tracing the ray path of the electron beams under the magnetic fields inside the objective lens.

Study on The Electron-Beam Optics in The Micro-Column for The Multi-Beam Lithography (다중빔 리소그래피를 위한 초소형 컬럼의 전자빔 광학 해석에 관한 연구)

  • Lee, Eung-Ki
    • Journal of the Semiconductor & Display Technology
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    • v.8 no.4
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    • pp.43-48
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    • 2009
  • The aim of this paper is to describe the development of the electron-beam optic analysis algorithm for simulating the e-beam behavior concerned with electrostatic lenses and their focal properties in the micro-column of the multi-beam lithography system. The electrostatic lens consists of an array of electrodes held at different potentials. The electrostatic lens, the so-called einzel lens, which is composed of three electrodes, is used to focus the electron beam by adjusting the voltages of the electrodes. The optics of an electron beam penetrating a region of an electric field is similar to the situation in light optics. The electron is accelerated or decelerated, and the trajectory depends on the angle of incidence with respect to the equi-potential surfaces of the field. The performance parameters, such as the working distances and the beam diameters are obtained by the computational simulations as a function of the focusing voltages of the einzel lens electrodes. Based on the developed simulation algorithm, the high performance of the micro-column can be achieved through optimized control of the einzel lens.

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Electron Microscopic Studies on Distribution of Collagen IV of Lens Capsule and Apoptosis of Lens Epithelium in Age-related Cataractous Human (백내장 환자의 연령에 따른 수정체낭 Type IV 아교섬유의 분포와 수정체낭 상피세포 자연사 및 전자현미경적 변화에 대한 연구)

  • Heo, Jun;Yang, Young-Chul;Won, In-Gun
    • Biomedical Science Letters
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    • v.4 no.2
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    • pp.77-86
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    • 1998
  • Age-related changes in the lens capsule and epithelium of cataractous patients, ranging from 20 to 7o years old, were studied by means or LM, immunohistochemistry, and TEM. The lens capsule was divided into four zones; the anterior, subanterior, middle, and basal zone. The van Gieson staining reaction for collagen was prominent at the anterior and subanterior parts of the lens capsule. The reaction was more decreased in the elder group than the younger group. The collagen type IV reaction was prominent at the anterior zone of the lens capsule and around the cell. The reaction was more decreased in the elder group than the younger group. 3. The Periodic Acid Shiff-Alcian Blue reaction for mucopolysaccharide was prominent at the anterior zone of the lens capsule. The reaction was more decreased in the elder group than the younger group. The Apoptotic reaction was prominent at the nucleus of the lens epithelial cell. In the elder the cataractous group, the number of the apoptotic cells was more decreased. The electron microscopic change of lens epithelial cells were characterized by the increase of lateral fold and the cytoplasm with various vacuoles and Golgi complex. In the basal part, lens epithelial cell protruded toward the lens capsule in the 20-year-old group. The basal part of the 40-year-old group was flattened and covered with the cytoplasmic processes of adjacent cells. In the 60-year-old group, the mass of rough filaments separated lens capsule and the basal part of the lens epithelial cell. The electron microscopic change of the middle part of lens capsule was characterized by the aggregation of electron dense materials in the 40-year-old group, and the appearance of filamentous materials and the decrease of electron dense granules in the 60-year-old group.

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Electron Beam Behaviors by the Electrostatic Lens in Triode Field Emission Gun (3극 전계방출 전자총의 정전기 렌즈에 의한 전자빔 거동)

  • Kim, Chung-Soo;Kim, Dong-Hwan;Park, Man-Jin;Jang, Dong-Young;Han, Dong-Chul
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.6
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    • pp.163-167
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    • 2007
  • A field emission electron gun including 3 electrodes including one cathode and two anodes is very important for high resolution electron microscope. To have functions to control the initially-emitted electron beam, two anodes act as an electrostatic lens according to equipotential lines by adjusting the spot size, intensity, and working distance. To verify the action of the electron beam by the electrostatic lens by changing several parameters such as electrode shape, displacement and applied voltage to the electrodes, the two lenses were design and simulated and then their performances were analyzed with angular beam intensity(distribution), electrical optic axis variation and their stability.

A Study on the Influence of Pure Iron Purity of Electric Lens on the Electron Beam Control (전자빔 가공기의 전자렌즈 순철순도가 빔 제어에 미치는 영향)

  • Lee Chan-Hong;Ro Seung-Kook
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.149-153
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    • 2005
  • The electron beam machining provides very high resolution up to nanometer scale, hence the E-beam writing technology is rapidly growing in MEMS and nano-engineering areas. In the optical column of the e-beam writer, there are several lenses condensing and focusing electron beams from electron gun with fringing magnetic fields. The polepieces of these lenses are usually made with high purity iron which is hard to fabricate and very expensive. In this paper, the possibility of using polepiece of object lens composed with pure iron and low carbon steel was examined to reduce cost. The magnetic field at object lens was calculated with finite element method, and practical focusing qualities of SEM pictures were observed comparing for the object lens polepieces with pure iron and two type of composed with low carbon steel.

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Simple Analysis of the Properties of Condenser Lens 1 in SEM (SEM에서 접속 렌즈 1 의 특성에 대한 간단한 분석)

  • Lim, Sun-Jong
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.19 no.5
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    • pp.705-709
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    • 2010
  • It is quite complex to draw the geometry of electron trajectories in electron optics because such trajectories have various aberrations that cannot be easily calculated. However, if we need to know roughly the geometry, the focal length and the principal planes in order to understand the properties of column, a simple numerical solution can be a useful method. We are developing the electron beam machining system based on SEM. In this paper, we show rough geometry, focal length and principal planes by a numerical solution for electron lens I in our column. These results will be utilized in developing a simulation program for electron optics.

Development of Electron Gun 'S-CXO'

  • Kwon, Yong-Geol;Kim, Deog-Ho;Lee, Yang-Je;Yun, Kwang-Jin;Yoon, Young-Jun
    • Journal of Information Display
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    • v.2 no.1
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    • pp.43-46
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    • 2001
  • To meet the demand of the display market for large, flat, high-resolution screen, the Super Common eXtended field Oval lens (S-CXO) has been developed with resolution improvement of 10% or more compared to a conventional electron gun. A new main lens structure is adopted, to enhance the effectiveness of aperture and the performance. The new main lens can be assembled using an existing assembly system

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