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Applied Optics

Applied Optics

APPLICATIONS-CENTERED RESEARCH IN OPTICS

  • Vol. 38, Iss. 28 — Oct. 1, 1999
  • pp: 5920–5930

Characterization of diffraction gratings in a rigorous domain with optical scatterometry: hierarchical neural-network model

Ilkka Kallioniemi, Jyrki Saarinen, and Erkki Oja  »View Author Affiliations


Applied Optics, Vol. 38, Issue 28, pp. 5920-5930 (1999)
http://dx.doi.org/10.1364/AO.38.005920


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Abstract

Characterization of microstructures with features from submicrometers to hundreds of micrometers requires versatile methods. Profilometry and optical microscopy cannot cope with submicrometer features, and atomic-force microscopy, scanning-electron microscopy, and near-field microscopy are inherently slow, off-line methods. In optical scatterometry, the laser light scattered from a sample is measured and the sample profile is subsequently characterized. We propose the use of a two-stage model based on neural networks: rough categorization followed by refinement, thus reducing the need for prior information on the sample. We simulate the method for a submicrometer diffraction grating characterized by five parameters. It is shown that intensity measurements of few diffraction orders by use only of one wavelength are enough to yield rms errors of less than 2 nm for the parameters (approximately 2–3% of the optimal values of the parameters).

© 1999 Optical Society of America

OCIS Codes
(000.4430) General : Numerical approximation and analysis
(050.1950) Diffraction and gratings : Diffraction gratings
(050.1970) Diffraction and gratings : Diffractive optics
(120.5820) Instrumentation, measurement, and metrology : Scattering measurements
(260.2110) Physical optics : Electromagnetic optics

History
Original Manuscript: March 19, 1999
Revised Manuscript: June 17, 1999
Published: October 1, 1999

Citation
Ilkka Kallioniemi, Jyrki Saarinen, and Erkki Oja, "Characterization of diffraction gratings in a rigorous domain with optical scatterometry: hierarchical neural-network model," Appl. Opt. 38, 5920-5930 (1999)
http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-38-28-5920


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References

  1. B. W. Smith, “Strategies toward sub-0.25 µm lithography,” Opt. Photon. News 83(3), 23–27 (1997). [CrossRef]
  2. J. R. McNeil, S. S. H. Naqvi, S. M. Gaspar, K. C. Hickman, K. P. Bishop, L. M. Milner, R. H. Krukar, G. A. Petersen, “Scatterometry applied to microelectronics processing. 1,” Solid State Technol. 36, 29–32 (1993).
  3. J. R. McNeil, S. S. H. Naqvi, S. M. Gaspar, K. C. Hickman, K. P. Bishop, L. M. Milner, R. H. Krukar, G. A. Petersen, “Scatterometry applied to microelectronics processing. 2,” Solid State Technol. 36, 53–56 (1993).
  4. Z. R. Hatab, S. L. Prins, S. S. H. Naqvi, J. R. McNeil, “16 MB DRAM trench depth characterization using dome scatterometry,” Appl. Surf. Sci. 86, 597–599 (1995). [CrossRef]
  5. S. Zaidi, S. L. Prins, J. R. McNeil, S. S. H. Naqvi, “Metrology sensors for advanced resists,” in Integrated Circuit Metrology, Inspection, and Process Control VII, M. H. Bennett, ed., Proc. SPIE2196, 341–351 (1994).
  6. I. J. Wilson, L. C. Botten, “Groove depth determination using a laser for sinusoidal groove gratings,” Appl. Opt. 16, 2086–2089 (1977). [CrossRef] [PubMed]
  7. S. S. H. Naqvi, S. Kaspar, K. Hickman, K. Bishop, J. R. McNeil, “Linewidth measurement of gratings on photomasks: a simple technique,” Appl. Opt. 31, 1377–1384 (1992). [CrossRef] [PubMed]
  8. C. J. Raymond, M. R. Murmane, S. S. H. Naqvi, J. R. McNeil, “A scatterometric sensor for lithography,” in Manufacturing Process Control for Microelectronic Devices and Circuits, A. G. Sabnis, ed., Proc. SPIE2336, 37–49 (1994). [CrossRef]
  9. B. K. Minhas, S. L. Prins, S. S. H. Naqvi, J. R. McNeil, “Towards sub-0.1 µm CD measurements using scatterometry,” in Metrology, Inspection, and Process Control for Microlithography X, S. K. Jones, ed., Proc. SPIE2725, 729–739 (1996). [CrossRef]
  10. K. P. Giapis, R. A. Gottscho, L. A. Clark, J. B. Kruskal, D. Lambert, A. Kornblit, D. Sinatore, “Use of light scattering in characterizing reactively ion etched profiles,” J. Vac. Sci. Technol. A 9, 664–668 (1991). [CrossRef]
  11. R. Krukar, A. Kornblit, L. A. Clark, J. Kruskal, D. Lambert, E. A. Reitman, R. A. Gottscho, “Reactive ion etching profile and depth characterization using statistical and neural analysis of light scattering data,” J. Appl. Phys. 74, 3698–3706 (1993). [CrossRef]
  12. S. S. H. Naqvi, R. H. Krukar, J. R. McNeil, J. E. Franke, T. M. Niemczyk, D. M. Haaland, R. A. Gottscho, A. Kornblit, “Etch depth estimation of large-period silicon gratings with multivariate calibration of rigorously simulated diffraction profiles,” J. Opt. Soc. Am. A 11, 2485–2493 (1994). [CrossRef]
  13. J. Bischoff, J. W. Baumgart, H. Truckenbrodt, J. J. Bauer, “Photoresist metrology based on light scattering,” in Metrology, Inspection, and Process Control for Microlithography X, S. K. Jones, ed., Proc. SPIE2725, 678–689 (1996). [CrossRef]
  14. N. George, S.-G. Wang, “Neural networks applied to diffraction-pattern sampling,” Appl. Opt. 33, 3127–3134 (1994). [CrossRef] [PubMed]
  15. D. J. Search, C. A. Hobson, J. T. Atkinson, J. D. Pearson, “Diffraction pattern analysis for automatic defect classification in manufactured electronic assemblies,” in Machine Vision Applications in Industrial Inspection II, B. M. Dawson, S. S. Wilson, F. Y. Wu, eds., Proc. SPIE2183, 170–179 (1994). [CrossRef]
  16. I. Kallioniemi, J. Saarinen, E. Oja, “Optical scatterometry of subwavelength diffraction gratings: neural network approach,” Appl. Opt. 37, 5830–5835 (1998). [CrossRef]
  17. S. Haykin, Neural Networks—A Comprehensive Foundation, 2nd ed. (Prentice-Hall, Englewood Cliffs, N.J., 1999).
  18. C. M. Bishop, Neural Networks for Pattern Recognition (Oxford U. Press, New York, 1995).
  19. J. Saarinen, E. Noponen, J. Turunen, T. Suhara, H. Nishihara, “Asymmetric beam deflection by doubly grooved binary gratings,” Appl. Opt. 33, 2401–2405 (1995). [CrossRef]
  20. M. B. Stern, “Binary optics fabrication,” in Micro-Optics: Elements, Systems and Applications, H. P. Herzig, ed. (Taylor & Francis, London, 1997).
  21. M. G. Moharam, T. K. Gaylord, “Rigorous coupled-wave analysis of planar-grating diffraction,” J. Opt. Soc. Am. 71, 811–818 (1981). [CrossRef]
  22. D. Nguyen, B. Widrow, “The truck back-upper: an example of self-learning in neural networks,” in Neural Networks for Robotics and Control, W. T. Miller, R. Sutton, P. Werbos, eds. (MIT Press, Cambridge, Mass., 1990).

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