Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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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
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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.

열 전자 방출 형 전자 빔 장치에서 영상을 획득하기 위해서는 텅스텐 필라멘트에서 발생한 전자빔을 스캔 할 장치가 필요하다. 이때, 스캔 되는 주파수에 따라서 시료 표면에서 튀어 나오는 2 차 전자신호에 대하여 잡음 성분의 발생이 다르게 나타난다. 본 연구에서는 잡음 성분 제거를 위한 필터 설계를 위해서 2 차 전자신호에 대한 실시간 주파수 분석을 통해 신호와 잡음 성분을 구분했다. 그리고 부동 소수점 연산이 가능한 DSP 에서 디지털 필터 설계를 통하여 신호대비 잡음 성분 제거를 통하여 고배율로 획득한 전자현미경의 영상의 질을 향상 시켰다.

Keywords

References

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