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Study on Real-Time Digital Filter Design as Function of Scanning Frequency of Focused Electron Beam

집속 전자 빔 장치에서 스캔 주파수에 따른 실시간 디지털 필터 설계에 관한 연구

  • Kim, Seung-Jae (Nano Manufacturing Device, Seoul Nat'l Univ. of Science and Technology) ;
  • Oh, Se-Kyu (Nano Manufacturing Device, Seoul Nat'l Univ. of Science and Technology) ;
  • Yang, Kyung-Sun (Nano Manufacturing Device, Seoul Nat'l Univ. of Science and Technology) ;
  • Jung, Kwang-Oh (Graduate School of NID Fusion Tech, Seoul Nat'l Univ. of Science and Technology) ;
  • Kim, Dong-Hwan (Dept. of Mechanical and Automation Engineering, Seoul Nat'l Univ. of Science and Technology)
  • 김승재 (서울과학기술대학교 나노생산기술연구소) ;
  • 오세규 (서울과학기술대학교 나노생산기술연구소) ;
  • 양경선 (서울과학기술대학교 나노생산기술연구소) ;
  • 정광오 (서울과학기술대학교, NID 융합기술대학원 나노 IT 융합프로그램) ;
  • 김동환 (서울과학기술대학교 기계설계자동화공학부)
  • Received : 2010.06.15
  • Accepted : 2011.02.10
  • Published : 2011.05.01

Abstract

To acquire images in a thermionic-scanning electron-beam system, a scanning unit is needed to control the electron beam emitted from the tungsten filament source. In scanning the electron beam on the solid surface, the signalto-noise ratio depends on the scanning frequency. We used a digital filter to reduce noise by analyzing the real-time frequency of a secondary electron signal. The noise and the true image signal were well separated. We designed the digital filter via a DSP floating-point operation, and the noise elimination resulted in enhanced image quality in a highresolution mode.

Keywords

DSP;Digital Filter;Frequency Analysis;Bandwidth Sampling Frequency;Signal Generator;SEM

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