• 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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.489-490
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.449-450
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• 2008

• 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.

• 한국공작기계학회논문집
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• 제16권5호
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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.

• 한국레이저가공학회지
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• 제12권2호
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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.

• 한국정밀공학회지
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• 제26권11호
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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.

• 한국생산제조학회지
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• 제19권5호
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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.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.15-18
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• 2005

We have designed and fabricated a thermal scanning electron microscopy. It includes an electron source, two condenser lenses, one objective lens, a scanning coil and a stigmator coil for focusing in column and also have a secondary electron detector for constructing the image in chamber with a high vacuum condition and control part for operating the SEM. Especially, in order for us to find out the optical characteristics, our attention and studies have been concentrated on the effects of two condenser lenses and one objective lens for high resolution with SEM. Finally, we developed a high resolution thermal scanning electron microscopy.

• 한국정밀공학회지
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• 제26권4호
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• pp.128-133
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• 2009

Focused-ion-beam (FIB) system is capable of both machining and measuring in nano-scale; hence nano-scale focusing quality is important. This paper investigates design parameters of two electrostatic lenses in order to achieve the best ion beam focusing performance. Commercial SIMION simulator is used to optimize the dimensions of the condenser and objective lenses and investigate the influence of assembly error on focusing quality The simulation results show that the beam focusing quality is not influenced by angle deviation within ${\pm}0.02\;deg$ and geometrical eccentricity within ${\pm}50$ micrometers.