Abstract

We describe an improved scheme of spectrally resolved white-light interferometry, which provides 3D visual inspection of a thin-film layer structure with nanometer level resolutions. Compared to the authors’ previous method [Appl. Phys. Lett. 91, 091903 (2007)], 3D tomographic information of thin films can be obtained by decoupling the film thickness and top surface profile, which is embodied by inducing spectral carrier frequency to the reference arm and applying a low-pass filter to the interfero gram instead of two troublesome measurement steps of activating and deactivating a mechanical shutter. We test and verify our proposed method by measuring a patterned thin-film layer structure as well as standard specimens of thin films with various thicknesses.

© 2009 Optical Society of America

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References

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2007

2006

2002

1999

1996

1994

1993

P. de Groot and L. Deck, “Three-dimensional imaging by sub-Nyquist sampling of white-light interferograms,” Opt. Lett. 18, 1462-1464 (1993).
[CrossRef] [PubMed]

J. T. Fanton, J. Opsal, D. L. Willenborg, S. M. Kelso, and A. Rosenwaig, “Multiparameter measurements of thin films using beam-profile reflectometry,” J. Appl. Phys. 73, 7035-7040 (1993).
[CrossRef]

1992

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

1982

A. Azzam, R. M.

R. M. A. Azzam and N. M. Bashara, Ellipsometry and Polarized Light (North-Holland, 1979).

Bashara, N. M.

R. M. A. Azzam and N. M. Bashara, Ellipsometry and Polarized Light (North-Holland, 1979).

Colonna de Lega, X.

X. Colonna de Lega and P. de Groot, “Interferometry method and system including spectral decomposition,” International Patent WO 2007/044786 A2 (19 April 2007).

Dandliker, R.

de Groot, P.

de Lega, X. Colonna

Debnath, S. K.

Deck, L.

Fanton, J. T.

J. T. Fanton, J. Opsal, D. L. Willenborg, S. M. Kelso, and A. Rosenwaig, “Multiparameter measurements of thin films using beam-profile reflectometry,” J. Appl. Phys. 73, 7035-7040 (1993).
[CrossRef]

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

Ghim, Y.-S.

Gray, S.

Hariharan, P.

Ina, H.

Kelso, S. M.

J. T. Fanton, J. Opsal, D. L. Willenborg, S. M. Kelso, and A. Rosenwaig, “Multiparameter measurements of thin films using beam-profile reflectometry,” J. Appl. Phys. 73, 7035-7040 (1993).
[CrossRef]

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

Kim, D.

Kim, G.-H.

Kim, S.

Kim, S.-W.

Kobayashi, S.

Kong, H. J.

Kothiyal, M. P.

Lee, Y.

McGahan, W. A.

H. G. Tompkins and W. A. McGahan, Spectroscopic Ellipsometry and Reflectometry: User's Guide (Wiley, 1999).

Opsal, J.

J. T. Fanton, J. Opsal, D. L. Willenborg, S. M. Kelso, and A. Rosenwaig, “Multiparameter measurements of thin films using beam-profile reflectometry,” J. Appl. Phys. 73, 7035-7040 (1993).
[CrossRef]

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

Rosenwaig, A.

J. T. Fanton, J. Opsal, D. L. Willenborg, S. M. Kelso, and A. Rosenwaig, “Multiparameter measurements of thin films using beam-profile reflectometry,” J. Appl. Phys. 73, 7035-7040 (1993).
[CrossRef]

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

Schmit, J.

Schnell, U.

Schwider, J.

Takeda, M.

Tompkins, H. G.

H. G. Tompkins and W. A. McGahan, Spectroscopic Ellipsometry and Reflectometry: User's Guide (Wiley, 1999).

Willenborg, D. L.

J. T. Fanton, J. Opsal, D. L. Willenborg, S. M. Kelso, and A. Rosenwaig, “Multiparameter measurements of thin films using beam-profile reflectometry,” J. Appl. Phys. 73, 7035-7040 (1993).
[CrossRef]

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

Zhou, L.

Appl. Opt.

Appl. Phys. Lett.

Y.-S. Ghim and S.-W. Kim, “Fast, precise, tomograhic measurements of thin films,” Appl. Phys. Lett. 91, 091903 (2007).
[CrossRef]

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

J. Appl. Phys.

J. T. Fanton, J. Opsal, D. L. Willenborg, S. M. Kelso, and A. Rosenwaig, “Multiparameter measurements of thin films using beam-profile reflectometry,” J. Appl. Phys. 73, 7035-7040 (1993).
[CrossRef]

J. Opt. Soc. Am.

Opt. Express

Opt. Lett.

Other

The Levenberg-Marquardt function is available as LEASTSQ by commercial MATLAB software.

H. G. Tompkins and W. A. McGahan, Spectroscopic Ellipsometry and Reflectometry: User's Guide (Wiley, 1999).

R. M. A. Azzam and N. M. Bashara, Ellipsometry and Polarized Light (North-Holland, 1979).

X. Colonna de Lega and P. de Groot, “Interferometry method and system including spectral decomposition,” International Patent WO 2007/044786 A2 (19 April 2007).

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Figures (3)

Fig. 1
Fig. 1

Schematic diagram of spectrally resolved white-light interferometry for the thickness profile measurement of thin-film layers: OL, objective lens; BS, beam splitter; LS, line slit; DE, dispersive element; CCD, charge coupled device.

Fig. 2
Fig. 2

Procedures for very thin-film thickness profile measurements: (a) measured intensity of the sample according to the wavenumber from 2D CCD; (b) Fourier-transformed signal of (a); (c) comparison of measured reflectance M ( k ) sam of the sample (solid line) and result of reflectance model T ( d ; k ) (x mark); and (d) phase distribution maps according to wavenumber (line 1, total phase distribution; line 2, phase distribution due to surface height; line 3, phase distribution due to thin-film thickness).

Fig. 3
Fig. 3

Exemplary measurement results: (a) top view of “check” patterned Si O 2 film layer on Si substrate and its manufacturing design; (b) its 3D thickness profile; (c) cross-sectional height of A A ; (d) cross-sectional thickness of A A

Tables (1)

Tables Icon

Table 1 Comparison Measurement Results of Standard Specimens

Equations (6)

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I ( h , d ; k ) = E tot E tot * = ( E r + E m ) ( E r + E m ) * = | E r | 2 + | E m | 2 + E r E m * + E r * E m = I 0 ( k ) + I 1 ( d ; k ) + I 2 ( k ) cos [ Φ ( h , d ; k ) + 2 k h c ] = I 0 ( k ) + I 1 ( d ; k ) + I 2 ( h , d ; k ) exp ( 2 k h c j ) + I 2 ( h , d ; k ) * exp ( 2 k h c j ) .
ψ ( d ; k ) = R ( d ; k ) , R ( d ; k ) = r 01 + r 12 exp ( j 2 k N d cos θ ) 1 + r 01 r 12 exp ( j 2 k N d cos θ ) ,
F I ( h , d ; k ) = Γ 0 ( f k ) + Γ 1 ( f k ) + Γ 2 ( f k h c ) + Γ 2 ( f k + h c ) * ,
R M ( k ) sam = I sam ( d ; k ) I ref ( k ) R ( 0 ; k ) ref .
χ ( d ; k ) 2 = i = 1 n | T i ( d ; k i ) M i ( k i ) sam | .
H = 1 2 d [ Φ ( H , d ; k ) ψ ( d ; k ) ] d k .

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