• Current Optics and Photonics
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• v.7 no.6
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• pp.755-760
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• 2023

In this paper, an illumination optical system that can mitigate the saturation phenomenon in the center of an image (caused by the typical flexible-endoscope illumination system using LEDs with Lambertian light distribution) is designed. When an LED with Lambertian light distribution is used as a light source, the amount of light in the center of the endoscopic illumination system is relatively high, compared to the periphery, causing saturation in the image. Since this phenomenon causes difficulty in detecting the patient's lesion, it is necessary to find a lighting-system design that can alleviate the saturation phenomenon. Therefore, in this paper a lighting system with bat-wing light distribution, which can lower the intensity at the center and secure the maximum amount of light at the maximum light distribution angle, is designed. In addition, to check the performance of the designed lighting system, a simulation of illumination and luminance is conducted for a system using a common aspherical lens with otherwise the same components. As a result, it is confirmed that the lighting system designed in this paper effectively reduces the luminance value at the center and secures more luminance values at the periphery than the familiar lighting system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.120-124
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• 2004

본 연구는 Diluted Ceria 입자를 사용한 $SiO_2$(Oxide) CMP 현상에 대한 내용이다. Ceria Slurry의 경우 Silica Slurry와 비교하였을 때 Oxide Wafer 표면과 축합 화학반응을 일으키며 Chemistry Dominant한 CMP Mechanism을 따르고, Wafer Center Removal Rate(RR) Fast 의 특성을 가진다. Ceria Slurry의 문제점인 연마 불균일도를 해결하기 위해 Tribological System을 이용하였다. CMP Tribology는 Pad-Slurry 유막-Wafer의 System을 가지며 윤활막에 작용하는 마찰계수(COF)가 주요 인자이다. Tribology에 적용되는 Stribeck Curve를 통해 Slurry 윤활막의 두께(h) 정도를 예상할 수 있으며, 이 윤활막의 두께를 조절함으로써 Uniformity 향상이 가능하다. 이 Ceria Slurry CMP의 연마 불균일도를 향상시킬 수 있는 방법으로 pH 조절 및 점도 증가가 있다. Ceria 입자 CMP는 분산액의 pH 변화에 강한 작용을 받게 되며 PH5 근방에서 최적화된 Uniformity가 가능하다. 점도를 증가시키는 경우 유막 h가 증가하게 되어 Ceria Slurry의 유동이 균일 분포 상태에 가까워지며 Wafer Uniformity 향상이 가능하다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.11
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• pp.760-766
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• 2010

Excessive heat occurs during semiconductor manufacturing process. Thus, precise control of temperature is required to maintain constant chamber-temperature and also wafer-temperature in the chamber. Compared to an industrial chiller, semiconductor chiller's power consumption is very high due to its continuous operation for a year. Considering the high power consumption, it is necessary to develop an energy efficient chiller by optimizing operation control. Therefore, in this study, a semiconductor chiller is experimentally investigated to suggest energy-saving direction by conducting load change, temperature rise and fall and control precision experiments. The experimental study shows the cooling capacity of dual-channel chiller rises over 30% comparing to the conventional chiller. The time and power consumption in the temperature rising experiment are 43 minutes and 8.4 kWh, respectively. The control precision is the same as ${\pm}1^{\circ}C$ at $0^{\circ}C$ in any cases. However, it appears that the dual channel's control precision improves to ${\pm}0.5^{\circ}C$ when the setting temperature is over $30^{\circ}C$.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.4
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• pp.1-8
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• 2009

The studies on semiconductor industrial accident in korea have been focused on the frequencies of each type of safety management employee, characteristics, cause and unsafe conditions, acts and so on. Those attributes of semiconductor industrial accidents were usually analyzed independently, so that it was hard to provides a wel-developed process and systematic guidelines for efficient safety management. Therefore, there were a few studies based on comprehensive survey in terms of the shape type of safe management. The questionnaire survey carried out for the 284 workers who were responsible for safety management in center with cooperation companies in semiconductor industry factor analysis showed that there were three factors of safety management. First, investment and operation and management for accident prevention, Second, unsafe act and condition, safety management Third, general human error and behavior. The industries of respondents were correlative with three groups. Three groups showed statistically significant differences on the number of cases. Actually, the group with the larger investment and the more unsafe cause, human error of accidents prevention had a smaller causes of accident cases.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.424-427
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• 2015

근래 들어 모바일 기기의 시스템을 장악하여 사용자의 기밀 정보를 빼내는 악성 행위의 한 방법으로 Code Reuse Attack (CRA)이 널리 사용되고 있다. 이와 같은 CRA를 막기 위하여 call-return이 일어날 때마다 이들 address를 비교해 보는 shadow stack과 branch에 대한 몇 가지 규칙을 두어 CRA 를 탐지하는 branch regulation과 같은 방식이 연구되었다. 우리는 shadow stack과 branch regulation을 종합하여 여러 종류의 CRA를 적은 성능 오버헤드로 탐지할 수 있는 CRA Detection System을 만들고자 한다. 이를 위하여 반드시 선행 되어야 할 연구인 바이너리 파일 분석과 meta-data 생성 및 압축 기술을 제안한다. 실험 결과 생성된 meta-data는 압축 기술을 적용하기 전보다 1/2에서 1/3 가량으로 그 크기가 줄어들었으며 CRA Detection System의 탐지가 정상적으로 동작하는 것 또한 확인할 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.05a
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• pp.216-218
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• 2021

최근 침입 탐지 시스템은 기존 시그니처 기반이 아닌 AI 기반 연구로 많이 진행되고 있다. 이는 시그니처 기반의 한계인 이전에 보지 못한 악성 행위의 탐지가 가능하기 때문이다. 또한 로그 정보는 시스템의 중요 이벤트를 기록하여 시스템의 상태를 반영하고 있기 때문에 로그 정보를 사용한 침입 탐지 시스템에 대한 연구가 활발히 이루어지고 있다. 하지만 로그 정보는 시스템 상태의 일부분만 반영하고 있기 때문에, 회피하기 쉬우며, 이를 보완하기 위해 system call 정보를 사용한 멀티 모달 기반 침입 시스템을 제안한다.

• Journal of the Semiconductor & Display Technology
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• v.12 no.2
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• pp.85-91
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• 2013

In this paper, the parabolic antenna aims to the precise location of a moving ship or car that can be designed system using the gyro sensor. The parabolic antenna has controlled by stepping motor that is a lot of noise and slow response of speed. It has solved the problem which is noise and slow response using the BLDC motor. Also, in order to suppress the noise two-axis control and a separate encoder to the six degrees of freedom motion system was implemented in a precise location. Generally, the gyro sensor is not required to system that doesn't move the six degrees of freedom motion system. But the system will be applied to the moving such as ships or cars. Finally, we presented the position control algorithm at the sometimes controlled both gyro sensor and BLDC motor. This system was tracking that the location of the antenna to the desired angle and errors almost didn't happen when the system was moved 6 degrees of freedom.

• Journal of the Semiconductor & Display Technology
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• v.12 no.4
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• pp.39-44
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• 2013

In the semiconductor heat-treatment process, the temperature uniformity determines the film quality of a wafer. This film quality effects on the overall yield rate. The heat transfer of the wafer surface in the heat-treatment process equipment is occurred by convection and radiation complexly. Because of this, there is the nonlinearity between the wafer temperature and reactor. Therefore, the accurate prediction of temperature on the wafer surface is difficult without the direct measurement. The thermal camera and the T/C wafer are general ways to confirm the temperature uniformity on the heat-treatment process. As above ways have limit to measure the temperature in the precise domain under the micro-scale. In this study, we developed the thin film type temperature sensor using the MEMS technology to establish the system which can measure the temperature under the micro-scale. We combined the experiment and numerical analysis to verify and calibrate the system. Finally, we measured the temperature on the wafer surface on the semiconductor process using the developed system, and confirmed the temperature variation by comparison with the commercial T/C wafer.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.2
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• pp.81-86
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• 2005

This paper proposes a non-destructive ESPI technique to quantitatively evaluate defects inside a semiconductor package. The inspection system consists of the ESPI system, a thermal loading system and an adiabatic chamber. The technique is high feasibility for non-destructive testing of a semiconductor and overcomes the weaknesses of previous techniques, such as time-consumption and difficult quantitative evaluation. Most defects are classified as delamination defects, resulting from the insufficient adhesive strength between layers and from non-homogeneous heat spread. Ninety percent of the tested samples had delamination defects which originated at the corner of the chip and nay be related to heat spread design.

• The KIPS Transactions:PartD
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• v.11D no.2
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• pp.461-470
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• 2004

As the semiconductor industrials change 200㎜-sized semiconductor wafer production process to 300㎜-sized one, it requires to develop the software for monitoring and simulating the robot which transfers a 300㎜-sized semiconductor wafer. Because such a software don't run at standalone but communicate MCS(Material Control System) and Its subsystem a robot, its architecture is very complex. Therefore, in order to develop such a software systematically, we must utilize an object-oriented development methodology. UML. This paper presents an UML process application developing the software for monitoring and simulating the robot which transfers a semiconductor wafer on the production process.