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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)

Abstract

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.

Keywords

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

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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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