Ultra-High Resolution Thin Film Thickness Delineation Using Reflection Phase-Sensitive Acoustic Microscopy

  • E. A. Mohamed
  • A. Kamanyi
  • M. von Buttlar
  • R. Wannemacher
  • K. Hillmann
  • W. Ngwa
  • W. Grill
Conference paper
Part of the Acoustical Imaging book series (ACIM, volume 30)


The acoustic phase and magnitude data of a planar homogenous sample of smoothly varying thickness deposited on a glass substrate can best be represented by a polar plot. In this work, the method is extended to achieve topographical mapping of thin films with a height resolution beyond the diffraction limit of optical confocal microscopy. The radial dependence of the polar graph describes the regression of the magnitude of the reflected signal due to the attenuation. The later increases with the gradual increase of the thickness and is additionally influenced by interference effects. The angular dependence of the polar plot reveals the rotation of the phase angle of the signal due to reflection from different thicknesses of the sample. Model calculations are employed, and input values are varied until an optimum agreement with the measurement data points is achieved and the primary acoustic properties (speed of longitudinally polarized ultrasound, mechanical density of the sample and the attenuation within the material) are obtained. The model manifests the variation of the magnitude and phase of the reflected signal due to variation in thickness. After optimum adjustment of the model parameters, the thickness corresponding to each measured value of the reflectivity is obtained.


Phase-sensitive Acoustic microscopy Polar Height profile Thin film thickness Ultraresolution 


  1. 1.
    Hänel, V.: Determination of sound velocity and thickness of thin samples by time-resolved acoustic microscopy. J. Appl. Phys. 84, 668–670 (1998)ADSCrossRefGoogle Scholar
  2. 2.
    Liang, K., Bennett, S.D., Khuri-Yakub, B.: Precision measurement of Rayleigh wave velocity perturbation. Phys. Lett. 41, 1124–1126 (1982)Google Scholar
  3. 3.
    Liang, K., Khuri-Yakub. B., Dennett, S., Kino, S.: Phase measurements in acoustic microscopy. IEEE Ultrasonic Symposium, 599–604 (1983)Google Scholar
  4. 4.
    Weglein, R.D.; Acoustic microscopy applied to SAW dispersion and film thickness measurement. IEEE Trans. Sonics Ultrason. 27, 82–86 (1980)Google Scholar
  5. 5.
    Crean, G., Waintal, A.: Average Rayleigh-wave velocity of a computer simulated crystallographic plane. J. Appl. Cryst. 19, 181–186 (1986)CrossRefGoogle Scholar
  6. 6.
    Sasaki, Y., Endo, T., Yamagishi, T., Sakai, M.: Thickness measurement of a thin–film layer on an anisotropic substrate by phase-sensitive acoustic microscope. IEEE Trans. Sonics Ultrason. 39, 638–642 (1992)Google Scholar
  7. 7.
    Ahmed Mohamed, E., Kamanyi, A., von Buttlar, M., Wannemacher, R., Hillmann, K., Ngwa, W., Grill, W.: Determination of mechanical properties of layered materials with vector contrast scanning acoustic microscopy by polar diagram image representation, Proceedings of SPIE 6935, 69351Z-69351Z-8 (2008)CrossRefGoogle Scholar
  8. 8.
    Hillmann, K., Grill, W., Bereiter-Hahn, J.: Determination of ultrasonic attenuation in small samples of solid material by scanning acoustic microscopy with phase contrast. J. Alloy. Comp. 151, 211–212 (1994)Google Scholar
  9. 9.
    Liang, K., Kino, G., Khuri-Yakub, B.: Material characterization by the inversion of V(z). IEEE. Trans. Sonics Ultrason. 32, 213–224 (1985)Google Scholar
  10. 10.
    Reinholdtsen, P., Chou, C-H., Khuri-Yakub, B.: Quantitative acoustic microscopy using amplitude and phase imaging. IEEE Ultrasonic symposium, pp. 807–811 (1987)Google Scholar
  11. 11.
    Brekhovskikh, L.: Waves in Layered Media, 2nd edn., pp. 5–46. Academic Press, INC, New York (1980)zbMATHGoogle Scholar
  12. 12.
    Litniewski, J., Bereiter-Hahn, J.: Measurements of cells in culture by scanning acoustic microscopy. J. Microsc. 158, 95–107 (1990)Google Scholar
  13. 13.
    Ngwa, W., Grill, W., Kundu, T.: Bio-soft-matter imaging and micrometrology by phase-sensitive ultrasonic microscopy. Proc. SPIE. 5394, 263–272 (2004)ADSCrossRefGoogle Scholar
  14. 14.
    Cloostermans, M., Verhoef, W., Thijssen, J.: Generalized description and tracking of the frequency dependent attenuation of ultrasound in biological tissue. Ultrason. Imag. 7, 133–141 (1985)CrossRefGoogle Scholar
  15. 15.
    Kundu, T., Bereiter-Hahn, J., Karl, I.: Cell property determination from the acoustic microscope generated voltage versus frequency curves. Biophys. J. 78, 2270–2279 (2000)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • E. A. Mohamed
    • 1
  • A. Kamanyi
    • 1
  • M. von Buttlar
    • 1
  • R. Wannemacher
    • 1
  • K. Hillmann
    • 2
  • W. Ngwa
    • 3
  • W. Grill
    • 1
  1. 1.Institute of Experimental Physics II, University of LeipzigLeipzigGermany
  2. 2.SAP Deutschland AG & Co. KGBensheimGermany
  3. 3.Department of PhysicsUniversity of Central FloridaOrlandoUSA

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