- Volume 35 Issue 5
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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
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.
DSP;Digital Filter;Frequency Analysis;Bandwidth Sampling Frequency;Signal Generator;SEM
- Park, K. Park, M. J., Kim, D. H. and Jang, D.Y., 2006, "Numerical Analysis for Electron Optical System of a Field Emission SEM," Trans. Kor. Soc. Mech. Engr. (A), Vol. 30, pp. 1577-1583.
- JEOL., 2006, Guide to Scanning Microscope, Observation, JEOL, Japan, pp. 5-35.
- Millman, J. and Grabel, A., 1988, Microelectronics, Mc Graw-Hill, New York, pp.118-201.
- Goldstein, J. I., Newbury, D. E., Echlin, P., Joy, D. C., Fiori, C. and Fifshin, E., 1989, Scanning Electron Microscopy and X-ray Microanalysis, Plenum Press, New York, Vol. 3, pp. 119-123.
- Kim, D.H., 1993, "Basic Theory and Application of Scanning Electron Microscopy," Analytical Science & Technology, Vol. 6, No. 2, pp. 53A-61A
- Kim, D.H., Kim, S.J., Park, M. J., Oh, S.K. and Jang, D.Y., 2008, "Methodologies for Enhancing Performance of Scan Drivers in a Scanning Electron Microscope," Proceeding of the KSME 2008 Spring Annual Conference, pp.22-23.
- Kim, S.J and Kim, D.H., 2009, "Scanning System Stability for Improving SEM Image," Journal of the Korean Society of Machine Tool Engineers, Vol.18, No.5, pp. 455-461.
- Hawkes, P.W., 2001, "Advance in Imaging and Electron Physics," Academic Press, San Diego Vol.115, pp.205-212.
- Grandner, F.M. 1986, "A Transformation for Digital Simulation of Analog Filters," IEE Trans. On Communications, Vol. 34, No. 7, pp. 676-680. https://doi.org/10.1109/TCOM.1986.1096607
- T.I, 2002, Filter Library, Texas Instruments, USA, pp. 1-17.
- Kossidas, A.T. and Pactitis, S.A., 1983, "Comb Filter-Simulation and Design," Mathematics and Computers in Simulation, Vol. 25, No. 1, pp. 27-30. https://doi.org/10.1016/0378-4754(83)90026-5
- Song, D.Y., Lee, S.H., Jung, T.U., Cho, S.E., Park, S.J. and Kim, D. O., 2008, "Development of Back-emf Filter Circuit for Driving Sensorless BLDC Motors,” The Korean Institute of Power Electronics, Vol. 13, No. 1, pp. 63-69.
- Ratajczak, P.M. and Katcki, J. J., 2006, "Elimination of Scanning Electron Microscopy Image Periodic Distortions with Digital Signal Processing Methods," Journal of Microscopy, Vol. 224, pp. 82-92.