Korean Journal of Optics and Photonics (한국광학회지)

Optical Society of Korea (한국광학회)
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Ellipsometric Expressions for a Near-normal-incidence Ellipsometer with the Polarizer-compensator-sample-compensator-analyzer Configuration

편광자-보정기-시료-보정기-검광자 배치를 가지는 준 수직입사 타원계의 타원식

  • Received : 2021.05.03
  • Accepted : 2021.05.24
  • Published : 2021.08.25
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Abstract

A near-normal-incidence ellipsometer (NNIE) is suggested as an optical critical dimension (OCD) measurement system that is highly sensitive to the bottom defect of a sample with high-aspect-ratio structured patterns. Incident light passes through a polarizer and a phase retarder in sequence, and the reflected light from the sample also passes through them, but in reverse order. The operating principle of this NNIE, where a single polarizer and a single phase retarder are shared by the incident and reflected light, is studied, and a method to determine the ellipsometric constants from the measured intensities at proper combinations of the azimuthal angles of polarizer and retarder is presented.

높은 종횡비를 가지는 미세 패턴 시료의 하부층 구조결함에 대해 높은 민감도를 가지는 광학적 임계치수 측정 장비로서 준 수직입사 타원계를 제안한다. 이 준 수직입사 타원계에서는 입사광은 편광자와 위상지연자를 순차적으로 통과하며 반사광은 이들을 역순으로 통과한다. 하나의 편광자와 하나의 위상지연자를 입사광과 반사광이 공유하며 편광자와 위상지연자의 여러 방위각 조합에서 측정한 빛의 세기로부터 타원상수를 결정하는 이 준 수직입사 타원계의 측정원리를 검토하고 최적의 타원상수 측정방법을 제시한다.

Keywords

Acknowledgement

본 연구는 한국산업기술진흥원(2020년 소재·부품·장비 양산성능평가지원사업, 과제번호: P0015756)의 지원으로 수행되었습니다.

References

  1. R. M. A. Azzam and N. M. Bashara, Ellipsometry and Polarized Light (North-Holland, Amsterdam, 1987).
  2. S. Y. Kim, Ellipsometry (Ajou University Press, Korea, 2000), Chapter 3-4.
  3. H. Fujiwara, Spectroscopic Ellipsometry: Principles and Applications (John Wiley & Sons, Tokyo, Japan, 2007), Chapter 5.
  4. D. E. Aspnes and A. A. Studna, "A high-precision scanning ellipsometer," Appl. Opt. 14, 220-228 (1975). https://doi.org/10.1364/AO.14.000220
  5. D. E. Aspnes and A. A. Studna, "Dielectric functions and optical parameters of Si, Ge, GaP, GaAs, GaSb, InP, InAs, and InSb from 1.5 to 6.0 eV," Phys. Rev. B 27, 985 (1983). https://doi.org/10.1103/PhysRevB.27.985
  6. K. Vedam and P. J. McMarr, "Nondestructive depth profiling by spectroscopic ellipsometry," Appl. Phys. Lett. 47, 339-341 (1985). https://doi.org/10.1063/1.96156
  7. K. Vedam and S. Y. Kim, "Simultaneous determination of refractive index, its dispersion and depth-profile of magnesium oxide thin film by spectroscopic ellipsometry," Appl. Opt. 28, 2691-2694 (1989). https://doi.org/10.1364/AO.28.002691
  8. T. Mori and D. E. Aspnes, "Comparison of the capabilities of rotating-analyzer and rotating-compensator ellipsometers by measurements on a single system," Thin Solid Films 455-456, 33-38 (2004). https://doi.org/10.1016/j.tsf.2003.12.037
  9. K. Ebert and D. E. Aspnes, "Biplate artifacts in rotating-compensator ellipsometers," Thin Solid Films 455-456, 779-783 (2004). https://doi.org/10.1016/j.tsf.2004.01.033
  10. J. N. Hilfiker, B. Johs, C. M. Herzinger, J. F. Elman, E. Montbach, D. Bryant, and P. J. Bos, "Generalized spectroscopic ellipsometry and Mueller-matrix study of twisted nematic and super twisted nematic liquid crystals," Thin Solid Films 455-456, 596-600 (2004). https://doi.org/10.1016/j.tsf.2004.01.031
  11. R. A. Synowicki, J. N. Hilfiker, and P. K. Whitman, "Mueller matrix ellipsometry study of uniaxial deuterated potassium dihydrogen phosphate (DKDP)," Thin Solid Films 455-456, 624-627 (2004). https://doi.org/10.1016/j.tsf.2004.02.027
  12. C. Chen, I. An, G. M. Ferreira, N. J. Podraza, J. A. Zapien, and R. W. Collins, "Multichannel Mueller matrix ellipsometer based on the dual rotating compensator principle," Thin Solid Films 455-456, 14-23 (2004). https://doi.org/10.1016/j.tsf.2003.11.191
  13. W. Ito, B. Bunday, S. Harada, A. Cordes, T. Murakawa, A. Arceo, M. Yoshikawa, T. Hara, T. Arai, S. Shida, M. Yamagata, J. Matsumoto, and T. Nakamura, "Novel three dimensional (3D) CD-SEM profile measurements," Proc. SPIE 9050, 90500D (2014). https://doi.org/10.1117/12.2047374
  14. K. Harafuji, N. Nomura, and T. Kouda, "On the image brightness of the trench bottom surface in a scanning electron microscope," J. Appl. Phys. 72, 2541-2548 (1992). https://doi.org/10.1063/1.351552
  15. M. Watanabe, S. Baba, T. Nakata, T. Morimoto, and S. Sekino, "A novel AFM method for sidewall measurement of high-aspect ratio patterns," Proc. SPIE 6922, 69220J (2008). https://doi.org/10.1117/12.772712
  16. H.-T. Huang and F. L. Terry Jr., "Erratum to 'Spectroscopic ellipsometry and reflectometry from gratings (Scatterometry) for critical dimension measurement and in situ, real-time process monitoring' [Thin Solid Films 455-456 (2004) 828-836]," Thin Solid Films 468, 339-346 (2004). https://doi.org/10.1016/j.tsf.2004.06.099
  17. W. Wei, S. Hou, Z. Wu, Y. Hu, Y. Wang, L. Chen, Y. Xiong, Y. Tian, and G. Liu, "Optical detection method for high aspect ratio microstructures," Macromachines 11, 296 (2020). https://doi.org/10.3390/mi11030296
  18. G. L. Whitworth, A. Francone, C. M. Sotomayor-Torres, and N. Kehagias, "Real-time optical dimensional metrology via diffractometry for nanofabrication," Sci. Rep. 10, 5371 (2020). https://doi.org/10.1038/s41598-020-61975-3
  19. KLA-Tencor Corporation, "Systems and methods for extended infrared spectroscopic ellipsometry," Korean Patent 20180095102A (2018).
  20. KLA-Tencor Corporation, "Method and system for measuring deep trenches in silicon," US patent 7369235B1 (2008).
  21. J. Li, B. Ramanujam, and R. W. Collins, "Dual rotating compensator ellipsometry: theory and simulations," Thin Solid Films 519, 2725-2729 (2011). https://doi.org/10.1016/j.tsf.2010.11.075