Abstract

We describe a scanning optical interferometer that can simultaneously perform ellipsometry measurements and thus provides a true surface profile. This is accomplished by projecting the back focal plane of the objective lens onto a CCD array. The measured phase differences between the p- and s-polarization components are converted, by using a specially developed algorithm, to optical phase changes caused by material variations. The compensation process is then applied to extract the true profile of the object surface. Experimental results obtained with the system are shown.

© 1996 Optical Society of America

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References

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  1. C. W. See, M. Vaez Iravani, H. K. Wickramasinghe, “Scanning differential phase contrast optical microscope—application to surface study,” Appl. Opt. 24, 2373–2379 (1985).
    [CrossRef] [PubMed]
  2. M. G. Somekh, M. S. Valera, R. K. Appel, “Scanning heterodyne confocal differential phase and intensity microscope,” Appl. Opt. 34, 4857–4868 (1995).
    [CrossRef] [PubMed]
  3. C. W. See, R. K. Appel, M. G. Somekh, “Scanning differential optical profilometer for simultaneous measurement of amplitude and phase variation,” Appl. Phys. Lett. 53, 10–12 (1988).
    [CrossRef]
  4. M. J. Downs, W. H. McGivern, H. J. Ferguson, “Optical system for measuring the profiles of super smooth surfaces,” Precis. Eng. 7, 211–215 (1985).
    [CrossRef]
  5. Y. Li, F. E. Talke, “Limitations and corrections of optical profilometry in surface characterization of carbon coated magnetic recording disks,” ASME J. Tribol. 112, 670–677 (1990).
    [CrossRef]
  6. M. Smallen, J. J. K. Lee, “Pole tip recession measurements on thin film heads using optical profilometry with phase correction and atomic force microscopy,” AMSE J. Tribol. 115, 382–386 (1993).
    [CrossRef]
  7. R. D. Holmes, C. W. See, M. G. Somekh, “Scanning micro-ellipsometry for extraction of true topography,” Electron. Lett. 31, 358–359 (1995).
    [CrossRef]
  8. R. M. A. Azzam, N. M. Bashara, Ellipsometry and Polarised Light (North-Holland, Amsterdam, 1992), Chap. 3, pp. 153–157.
  9. A. Rosencwaig, J. Opsal, D. L. Willenborg, S. M. Kelso, J. T. Fanton, “Beam profile reflectometry: a new technique for dielectric film measurements,” Appl. Phys. Lett. 60, 1301– 1303 (1992).
    [CrossRef]
  10. J. W. Goodman, Introduction to Fourier Optics (McGraw-Hill, New York, 1968), Chap. 5, pp. 83–90.
  11. M. Born, E. Wolf, Principles of Optics, 6th ed. (Pergamon, Oxford, 1980), Chap. 13, pp. 615–621.
  12. J. H. Bruning, D. R. Herriott, J. E. Gallanher, D. P. Rosenfeld, A. D. White, D. J. Brangaccio, “Digital wavefront measuring interferometer for testing optical surfaces and lenses,” Appl. Opt. 13, 2693–2703 (1974).
    [CrossRef] [PubMed]
  13. J. C. Wyant, C. L. Koliopoulos, B. Bhushan, D. Basila, “Development of a three-dimensional noncontact digital optical profiler,” ASME J. Tribol. 108, 1–8 (1986).
    [CrossRef]
  14. K. Creath, “Phase-measurement interferometry techniques,” in Progress in Optics, E. Wolf, ed. (Elsevier, New York, 1988), Vol. 26, Chap. 5, pp. 365–366.
    [CrossRef]
  15. Parameter δ is defined as δ = Δ + 180° so that at normal incidence, δ = 0°.
  16. Ref. 11, Chap. 7, pp. 324–325.
  17. TalyStep is manufactured by Rank Taylor Hobson Ltd., Leicester, United Kingdom.

1995 (2)

R. D. Holmes, C. W. See, M. G. Somekh, “Scanning micro-ellipsometry for extraction of true topography,” Electron. Lett. 31, 358–359 (1995).
[CrossRef]

M. G. Somekh, M. S. Valera, R. K. Appel, “Scanning heterodyne confocal differential phase and intensity microscope,” Appl. Opt. 34, 4857–4868 (1995).
[CrossRef] [PubMed]

1993 (1)

M. Smallen, J. J. K. Lee, “Pole tip recession measurements on thin film heads using optical profilometry with phase correction and atomic force microscopy,” AMSE J. Tribol. 115, 382–386 (1993).
[CrossRef]

1992 (1)

A. Rosencwaig, J. Opsal, D. L. Willenborg, S. M. Kelso, J. T. Fanton, “Beam profile reflectometry: a new technique for dielectric film measurements,” Appl. Phys. Lett. 60, 1301– 1303 (1992).
[CrossRef]

1990 (1)

Y. Li, F. E. Talke, “Limitations and corrections of optical profilometry in surface characterization of carbon coated magnetic recording disks,” ASME J. Tribol. 112, 670–677 (1990).
[CrossRef]

1988 (1)

C. W. See, R. K. Appel, M. G. Somekh, “Scanning differential optical profilometer for simultaneous measurement of amplitude and phase variation,” Appl. Phys. Lett. 53, 10–12 (1988).
[CrossRef]

1986 (1)

J. C. Wyant, C. L. Koliopoulos, B. Bhushan, D. Basila, “Development of a three-dimensional noncontact digital optical profiler,” ASME J. Tribol. 108, 1–8 (1986).
[CrossRef]

1985 (2)

M. J. Downs, W. H. McGivern, H. J. Ferguson, “Optical system for measuring the profiles of super smooth surfaces,” Precis. Eng. 7, 211–215 (1985).
[CrossRef]

C. W. See, M. Vaez Iravani, H. K. Wickramasinghe, “Scanning differential phase contrast optical microscope—application to surface study,” Appl. Opt. 24, 2373–2379 (1985).
[CrossRef] [PubMed]

1974 (1)

Appel, R. K.

M. G. Somekh, M. S. Valera, R. K. Appel, “Scanning heterodyne confocal differential phase and intensity microscope,” Appl. Opt. 34, 4857–4868 (1995).
[CrossRef] [PubMed]

C. W. See, R. K. Appel, M. G. Somekh, “Scanning differential optical profilometer for simultaneous measurement of amplitude and phase variation,” Appl. Phys. Lett. 53, 10–12 (1988).
[CrossRef]

Azzam, R. M. A.

R. M. A. Azzam, N. M. Bashara, Ellipsometry and Polarised Light (North-Holland, Amsterdam, 1992), Chap. 3, pp. 153–157.

Bashara, N. M.

R. M. A. Azzam, N. M. Bashara, Ellipsometry and Polarised Light (North-Holland, Amsterdam, 1992), Chap. 3, pp. 153–157.

Basila, D.

J. C. Wyant, C. L. Koliopoulos, B. Bhushan, D. Basila, “Development of a three-dimensional noncontact digital optical profiler,” ASME J. Tribol. 108, 1–8 (1986).
[CrossRef]

Bhushan, B.

J. C. Wyant, C. L. Koliopoulos, B. Bhushan, D. Basila, “Development of a three-dimensional noncontact digital optical profiler,” ASME J. Tribol. 108, 1–8 (1986).
[CrossRef]

Born, M.

M. Born, E. Wolf, Principles of Optics, 6th ed. (Pergamon, Oxford, 1980), Chap. 13, pp. 615–621.

Brangaccio, D. J.

Bruning, J. H.

Creath, K.

K. Creath, “Phase-measurement interferometry techniques,” in Progress in Optics, E. Wolf, ed. (Elsevier, New York, 1988), Vol. 26, Chap. 5, pp. 365–366.
[CrossRef]

Downs, M. J.

M. J. Downs, W. H. McGivern, H. J. Ferguson, “Optical system for measuring the profiles of super smooth surfaces,” Precis. Eng. 7, 211–215 (1985).
[CrossRef]

Fanton, J. T.

A. Rosencwaig, J. Opsal, D. L. Willenborg, S. M. Kelso, J. T. Fanton, “Beam profile reflectometry: a new technique for dielectric film measurements,” Appl. Phys. Lett. 60, 1301– 1303 (1992).
[CrossRef]

Ferguson, H. J.

M. J. Downs, W. H. McGivern, H. J. Ferguson, “Optical system for measuring the profiles of super smooth surfaces,” Precis. Eng. 7, 211–215 (1985).
[CrossRef]

Gallanher, J. E.

Goodman, J. W.

J. W. Goodman, Introduction to Fourier Optics (McGraw-Hill, New York, 1968), Chap. 5, pp. 83–90.

Herriott, D. R.

Holmes, R. D.

R. D. Holmes, C. W. See, M. G. Somekh, “Scanning micro-ellipsometry for extraction of true topography,” Electron. Lett. 31, 358–359 (1995).
[CrossRef]

Kelso, S. M.

A. Rosencwaig, J. Opsal, D. L. Willenborg, S. M. Kelso, J. T. Fanton, “Beam profile reflectometry: a new technique for dielectric film measurements,” Appl. Phys. Lett. 60, 1301– 1303 (1992).
[CrossRef]

Koliopoulos, C. L.

J. C. Wyant, C. L. Koliopoulos, B. Bhushan, D. Basila, “Development of a three-dimensional noncontact digital optical profiler,” ASME J. Tribol. 108, 1–8 (1986).
[CrossRef]

Lee, J. J. K.

M. Smallen, J. J. K. Lee, “Pole tip recession measurements on thin film heads using optical profilometry with phase correction and atomic force microscopy,” AMSE J. Tribol. 115, 382–386 (1993).
[CrossRef]

Li, Y.

Y. Li, F. E. Talke, “Limitations and corrections of optical profilometry in surface characterization of carbon coated magnetic recording disks,” ASME J. Tribol. 112, 670–677 (1990).
[CrossRef]

McGivern, W. H.

M. J. Downs, W. H. McGivern, H. J. Ferguson, “Optical system for measuring the profiles of super smooth surfaces,” Precis. Eng. 7, 211–215 (1985).
[CrossRef]

Opsal, J.

A. Rosencwaig, J. Opsal, D. L. Willenborg, S. M. Kelso, J. T. Fanton, “Beam profile reflectometry: a new technique for dielectric film measurements,” Appl. Phys. Lett. 60, 1301– 1303 (1992).
[CrossRef]

Rosencwaig, A.

A. Rosencwaig, J. Opsal, D. L. Willenborg, S. M. Kelso, J. T. Fanton, “Beam profile reflectometry: a new technique for dielectric film measurements,” Appl. Phys. Lett. 60, 1301– 1303 (1992).
[CrossRef]

Rosenfeld, D. P.

See, C. W.

R. D. Holmes, C. W. See, M. G. Somekh, “Scanning micro-ellipsometry for extraction of true topography,” Electron. Lett. 31, 358–359 (1995).
[CrossRef]

C. W. See, R. K. Appel, M. G. Somekh, “Scanning differential optical profilometer for simultaneous measurement of amplitude and phase variation,” Appl. Phys. Lett. 53, 10–12 (1988).
[CrossRef]

C. W. See, M. Vaez Iravani, H. K. Wickramasinghe, “Scanning differential phase contrast optical microscope—application to surface study,” Appl. Opt. 24, 2373–2379 (1985).
[CrossRef] [PubMed]

Smallen, M.

M. Smallen, J. J. K. Lee, “Pole tip recession measurements on thin film heads using optical profilometry with phase correction and atomic force microscopy,” AMSE J. Tribol. 115, 382–386 (1993).
[CrossRef]

Somekh, M. G.

M. G. Somekh, M. S. Valera, R. K. Appel, “Scanning heterodyne confocal differential phase and intensity microscope,” Appl. Opt. 34, 4857–4868 (1995).
[CrossRef] [PubMed]

R. D. Holmes, C. W. See, M. G. Somekh, “Scanning micro-ellipsometry for extraction of true topography,” Electron. Lett. 31, 358–359 (1995).
[CrossRef]

C. W. See, R. K. Appel, M. G. Somekh, “Scanning differential optical profilometer for simultaneous measurement of amplitude and phase variation,” Appl. Phys. Lett. 53, 10–12 (1988).
[CrossRef]

Talke, F. E.

Y. Li, F. E. Talke, “Limitations and corrections of optical profilometry in surface characterization of carbon coated magnetic recording disks,” ASME J. Tribol. 112, 670–677 (1990).
[CrossRef]

Vaez Iravani, M.

Valera, M. S.

White, A. D.

Wickramasinghe, H. K.

Willenborg, D. L.

A. Rosencwaig, J. Opsal, D. L. Willenborg, S. M. Kelso, J. T. Fanton, “Beam profile reflectometry: a new technique for dielectric film measurements,” Appl. Phys. Lett. 60, 1301– 1303 (1992).
[CrossRef]

Wolf, E.

M. Born, E. Wolf, Principles of Optics, 6th ed. (Pergamon, Oxford, 1980), Chap. 13, pp. 615–621.

Wyant, J. C.

J. C. Wyant, C. L. Koliopoulos, B. Bhushan, D. Basila, “Development of a three-dimensional noncontact digital optical profiler,” ASME J. Tribol. 108, 1–8 (1986).
[CrossRef]

AMSE J. Tribol. (1)

M. Smallen, J. J. K. Lee, “Pole tip recession measurements on thin film heads using optical profilometry with phase correction and atomic force microscopy,” AMSE J. Tribol. 115, 382–386 (1993).
[CrossRef]

Appl. Opt. (3)

Appl. Phys. Lett. (2)

A. Rosencwaig, J. Opsal, D. L. Willenborg, S. M. Kelso, J. T. Fanton, “Beam profile reflectometry: a new technique for dielectric film measurements,” Appl. Phys. Lett. 60, 1301– 1303 (1992).
[CrossRef]

C. W. See, R. K. Appel, M. G. Somekh, “Scanning differential optical profilometer for simultaneous measurement of amplitude and phase variation,” Appl. Phys. Lett. 53, 10–12 (1988).
[CrossRef]

ASME J. Tribol. (2)

J. C. Wyant, C. L. Koliopoulos, B. Bhushan, D. Basila, “Development of a three-dimensional noncontact digital optical profiler,” ASME J. Tribol. 108, 1–8 (1986).
[CrossRef]

Y. Li, F. E. Talke, “Limitations and corrections of optical profilometry in surface characterization of carbon coated magnetic recording disks,” ASME J. Tribol. 112, 670–677 (1990).
[CrossRef]

Electron. Lett. (1)

R. D. Holmes, C. W. See, M. G. Somekh, “Scanning micro-ellipsometry for extraction of true topography,” Electron. Lett. 31, 358–359 (1995).
[CrossRef]

Precis. Eng. (1)

M. J. Downs, W. H. McGivern, H. J. Ferguson, “Optical system for measuring the profiles of super smooth surfaces,” Precis. Eng. 7, 211–215 (1985).
[CrossRef]

Other (7)

R. M. A. Azzam, N. M. Bashara, Ellipsometry and Polarised Light (North-Holland, Amsterdam, 1992), Chap. 3, pp. 153–157.

K. Creath, “Phase-measurement interferometry techniques,” in Progress in Optics, E. Wolf, ed. (Elsevier, New York, 1988), Vol. 26, Chap. 5, pp. 365–366.
[CrossRef]

Parameter δ is defined as δ = Δ + 180° so that at normal incidence, δ = 0°.

Ref. 11, Chap. 7, pp. 324–325.

TalyStep is manufactured by Rank Taylor Hobson Ltd., Leicester, United Kingdom.

J. W. Goodman, Introduction to Fourier Optics (McGraw-Hill, New York, 1968), Chap. 5, pp. 83–90.

M. Born, E. Wolf, Principles of Optics, 6th ed. (Pergamon, Oxford, 1980), Chap. 13, pp. 615–621.

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Figures (6)

Fig. 1
Fig. 1

Objective lens and its back focal plane: principle of back focal plane ellipsometry.

Fig. 2
Fig. 2

Implementation of the optical system. BFP, back focal plane; BS, beam splitter.

Fig. 3
Fig. 3

Simulated optical phase shift as a function of δ for different n and κ values.

Fig. 4
Fig. 4

Least-squares straight-line fit through the data shown in Fig. 3.

Fig. 5
Fig. 5

Measured δ values as functions of incident angle for various materials.

Fig. 6
Fig. 6

Line scan profiles showing the results obtained with the phase compensation method.

Tables (2)

Tables Icon

Table 1 Simulated Phase Error Caused by the Nonuniform Amplitude Distribution of the Incident Beam

Tables Icon

Table 2 Error Associated with the Estimated Optical Phase Shift Obtained with the Linear Relation

Equations (4)

Equations on this page are rendered with MathJax. Learn more.

D 1 : E p ρ p exp ( j ϕ p ) , D 2 : E s ρ s exp ( j ϕ s ) ,
P = tan Ψ = ρ s ρ p , Δ = ϕ p ϕ s ,
θ m = a + b δ
E 0 = 1 + a 1 exp ( j θ ) + a 1 2 exp ( j 2 θ ) + a 1 3 exp ( j 3 θ ) + . = 1 1 a 1 exp ( j θ ) ,

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