Abstract

We present a novel all optical method for nanoscale pattern inspection. This method uses the chromatic aberration in an imaging optical system and a tunable light source. Such an approach allows stable and precise inspection of nanoscale objects based on an analysis of their defocused diffraction patterns without any external mechanical influence on the sample or optical system. We demonstrate the efficiency of a low cost light source tunable in the range of a light emitting diode bandwidth of ~30 nm (FWHM) for providing the required defocusing. The proposed method is tested using calibrated lines (height 50 nm, length 100 μm, critical dimension (СD) value range 40-150 nm with 10 nm steps) on a monocrystalline silicon substrate with demonstrated measurement accuracy better than 10 nm. A comparison of this all optical method with a mechanical scanning inspection system is discussed.

© 2014 Optical Society of America

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References

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  1. I. T. R. S. Roadmap, http://www.itrs.net/Links/2006Update/2006UpdateFinal.htm
  2. A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
    [CrossRef]
  3. D. Herisson, D. Neira, C. Fernand, P. Thony, D. Henry, S. Kremer, M. Polli, M. Guevremont, and A. Elazami, “Spectroscopic ellipsometry for lithography front-end level CD control: a complete analysis for production integration,” Proc. SPIE 5038, 264–273 (2003).
    [CrossRef]
  4. C. J. Raymond, M. Littau, R. Markle, and M. Purdy, “Scatterometry for shallow trench isolation (STI) process metrology,” Proc. SPIE 4344, 716–725 (2001).
    [CrossRef]
  5. R. M. Silver, R. Attota, M. Stocker, J. Jun, E. Marx, R. Larrabee, B. Russo, and M. Davidson, “Comparison of measured optical image profiles of silicon lines with two different theoretical models,” Proc. SPIE 4689, 409–429 (2002).
    [CrossRef]
  6. R. Attota, R. M. Silver, M. T. Stocker, E. Marx, J.-S. J. Jun, M. P. Davidson, and R. D. Larrabee, “A new method to enhance overlay tool performance,” Proc. SPIE 5038, 428–436 (2003).
    [CrossRef]
  7. R. Attota, R. M. Silver, M. R. Bishop, and R. G. Dixson, “Optical critical dimension measurement and illumination analysis using the through-focus focus metric,” Proc. SPIE 6152, 190–200 (2006).
  8. R. Attota, T. A. Germer, and R. M. Silver, “Through-focus scanning-optical-microscope imaging method for nanoscale dimensional analysis,” Opt. Lett. 33(17), 1990–1992 (2008).
    [CrossRef] [PubMed]
  9. M. V. Ryabko, S. N. Koptyaev, A. V. Shcherbakov, A. D. Lantsov, and S. Y. Oh, “Method for optical inspection of nanoscale objects based upon analysis of their defocused images and features of its practical implementation,” Opt. Express 21(21), 24483–24489 (2013).
    [CrossRef] [PubMed]
  10. J. Kim, D. Kang, and D. Gweon, “Spectrally encoded slit confocal microscopy,” Opt. Lett. 31(11), 1687–1689 (2006).
    [CrossRef] [PubMed]
  11. A. V. Arecchi, T. Messadi, and R. J. Koshel, Field Guide to Illumination (SPIE Press, 2007)

2013 (2)

A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
[CrossRef]

M. V. Ryabko, S. N. Koptyaev, A. V. Shcherbakov, A. D. Lantsov, and S. Y. Oh, “Method for optical inspection of nanoscale objects based upon analysis of their defocused images and features of its practical implementation,” Opt. Express 21(21), 24483–24489 (2013).
[CrossRef] [PubMed]

2008 (1)

2006 (2)

R. Attota, R. M. Silver, M. R. Bishop, and R. G. Dixson, “Optical critical dimension measurement and illumination analysis using the through-focus focus metric,” Proc. SPIE 6152, 190–200 (2006).

J. Kim, D. Kang, and D. Gweon, “Spectrally encoded slit confocal microscopy,” Opt. Lett. 31(11), 1687–1689 (2006).
[CrossRef] [PubMed]

2003 (2)

D. Herisson, D. Neira, C. Fernand, P. Thony, D. Henry, S. Kremer, M. Polli, M. Guevremont, and A. Elazami, “Spectroscopic ellipsometry for lithography front-end level CD control: a complete analysis for production integration,” Proc. SPIE 5038, 264–273 (2003).
[CrossRef]

R. Attota, R. M. Silver, M. T. Stocker, E. Marx, J.-S. J. Jun, M. P. Davidson, and R. D. Larrabee, “A new method to enhance overlay tool performance,” Proc. SPIE 5038, 428–436 (2003).
[CrossRef]

2002 (1)

R. M. Silver, R. Attota, M. Stocker, J. Jun, E. Marx, R. Larrabee, B. Russo, and M. Davidson, “Comparison of measured optical image profiles of silicon lines with two different theoretical models,” Proc. SPIE 4689, 409–429 (2002).
[CrossRef]

2001 (1)

C. J. Raymond, M. Littau, R. Markle, and M. Purdy, “Scatterometry for shallow trench isolation (STI) process metrology,” Proc. SPIE 4344, 716–725 (2001).
[CrossRef]

Agrawal, G.

A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
[CrossRef]

Allgair, J.

A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
[CrossRef]

Attota, R.

R. Attota, T. A. Germer, and R. M. Silver, “Through-focus scanning-optical-microscope imaging method for nanoscale dimensional analysis,” Opt. Lett. 33(17), 1990–1992 (2008).
[CrossRef] [PubMed]

R. Attota, R. M. Silver, M. R. Bishop, and R. G. Dixson, “Optical critical dimension measurement and illumination analysis using the through-focus focus metric,” Proc. SPIE 6152, 190–200 (2006).

R. Attota, R. M. Silver, M. T. Stocker, E. Marx, J.-S. J. Jun, M. P. Davidson, and R. D. Larrabee, “A new method to enhance overlay tool performance,” Proc. SPIE 5038, 428–436 (2003).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, J. Jun, E. Marx, R. Larrabee, B. Russo, and M. Davidson, “Comparison of measured optical image profiles of silicon lines with two different theoretical models,” Proc. SPIE 4689, 409–429 (2002).
[CrossRef]

Bishop, M. R.

R. Attota, R. M. Silver, M. R. Bishop, and R. G. Dixson, “Optical critical dimension measurement and illumination analysis using the through-focus focus metric,” Proc. SPIE 6152, 190–200 (2006).

Bozdog, C.

A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
[CrossRef]

Davidson, M.

R. M. Silver, R. Attota, M. Stocker, J. Jun, E. Marx, R. Larrabee, B. Russo, and M. Davidson, “Comparison of measured optical image profiles of silicon lines with two different theoretical models,” Proc. SPIE 4689, 409–429 (2002).
[CrossRef]

Davidson, M. P.

R. Attota, R. M. Silver, M. T. Stocker, E. Marx, J.-S. J. Jun, M. P. Davidson, and R. D. Larrabee, “A new method to enhance overlay tool performance,” Proc. SPIE 5038, 428–436 (2003).
[CrossRef]

Dixson, R. G.

R. Attota, R. M. Silver, M. R. Bishop, and R. G. Dixson, “Optical critical dimension measurement and illumination analysis using the through-focus focus metric,” Proc. SPIE 6152, 190–200 (2006).

Elazami, A.

D. Herisson, D. Neira, C. Fernand, P. Thony, D. Henry, S. Kremer, M. Polli, M. Guevremont, and A. Elazami, “Spectroscopic ellipsometry for lithography front-end level CD control: a complete analysis for production integration,” Proc. SPIE 5038, 264–273 (2003).
[CrossRef]

Fernand, C.

D. Herisson, D. Neira, C. Fernand, P. Thony, D. Henry, S. Kremer, M. Polli, M. Guevremont, and A. Elazami, “Spectroscopic ellipsometry for lithography front-end level CD control: a complete analysis for production integration,” Proc. SPIE 5038, 264–273 (2003).
[CrossRef]

Ford, C.

A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
[CrossRef]

Germer, T. A.

Guevremont, M.

D. Herisson, D. Neira, C. Fernand, P. Thony, D. Henry, S. Kremer, M. Polli, M. Guevremont, and A. Elazami, “Spectroscopic ellipsometry for lithography front-end level CD control: a complete analysis for production integration,” Proc. SPIE 5038, 264–273 (2003).
[CrossRef]

Gweon, D.

Hartig, C.

A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
[CrossRef]

Henry, D.

D. Herisson, D. Neira, C. Fernand, P. Thony, D. Henry, S. Kremer, M. Polli, M. Guevremont, and A. Elazami, “Spectroscopic ellipsometry for lithography front-end level CD control: a complete analysis for production integration,” Proc. SPIE 5038, 264–273 (2003).
[CrossRef]

Herisson, D.

D. Herisson, D. Neira, C. Fernand, P. Thony, D. Henry, S. Kremer, M. Polli, M. Guevremont, and A. Elazami, “Spectroscopic ellipsometry for lithography front-end level CD control: a complete analysis for production integration,” Proc. SPIE 5038, 264–273 (2003).
[CrossRef]

Iddawela, G.

A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
[CrossRef]

Isbester, P.

A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
[CrossRef]

Issascharoff, L.

A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
[CrossRef]

Jun, J.

R. M. Silver, R. Attota, M. Stocker, J. Jun, E. Marx, R. Larrabee, B. Russo, and M. Davidson, “Comparison of measured optical image profiles of silicon lines with two different theoretical models,” Proc. SPIE 4689, 409–429 (2002).
[CrossRef]

Jun, J.-S. J.

R. Attota, R. M. Silver, M. T. Stocker, E. Marx, J.-S. J. Jun, M. P. Davidson, and R. D. Larrabee, “A new method to enhance overlay tool performance,” Proc. SPIE 5038, 428–436 (2003).
[CrossRef]

Kang, B. C.

A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
[CrossRef]

Kang, D.

Kim, J.

Koptyaev, S. N.

Kremer, S.

D. Herisson, D. Neira, C. Fernand, P. Thony, D. Henry, S. Kremer, M. Polli, M. Guevremont, and A. Elazami, “Spectroscopic ellipsometry for lithography front-end level CD control: a complete analysis for production integration,” Proc. SPIE 5038, 264–273 (2003).
[CrossRef]

Lantsov, A. D.

Larrabee, R.

R. M. Silver, R. Attota, M. Stocker, J. Jun, E. Marx, R. Larrabee, B. Russo, and M. Davidson, “Comparison of measured optical image profiles of silicon lines with two different theoretical models,” Proc. SPIE 4689, 409–429 (2002).
[CrossRef]

Larrabee, R. D.

R. Attota, R. M. Silver, M. T. Stocker, E. Marx, J.-S. J. Jun, M. P. Davidson, and R. D. Larrabee, “A new method to enhance overlay tool performance,” Proc. SPIE 5038, 428–436 (2003).
[CrossRef]

Littau, M.

C. J. Raymond, M. Littau, R. Markle, and M. Purdy, “Scatterometry for shallow trench isolation (STI) process metrology,” Proc. SPIE 4344, 716–725 (2001).
[CrossRef]

Markle, R.

C. J. Raymond, M. Littau, R. Markle, and M. Purdy, “Scatterometry for shallow trench isolation (STI) process metrology,” Proc. SPIE 4344, 716–725 (2001).
[CrossRef]

Marx, E.

R. Attota, R. M. Silver, M. T. Stocker, E. Marx, J.-S. J. Jun, M. P. Davidson, and R. D. Larrabee, “A new method to enhance overlay tool performance,” Proc. SPIE 5038, 428–436 (2003).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, J. Jun, E. Marx, R. Larrabee, B. Russo, and M. Davidson, “Comparison of measured optical image profiles of silicon lines with two different theoretical models,” Proc. SPIE 4689, 409–429 (2002).
[CrossRef]

Neira, D.

D. Herisson, D. Neira, C. Fernand, P. Thony, D. Henry, S. Kremer, M. Polli, M. Guevremont, and A. Elazami, “Spectroscopic ellipsometry for lithography front-end level CD control: a complete analysis for production integration,” Proc. SPIE 5038, 264–273 (2003).
[CrossRef]

Oh, S. Y.

Polli, M.

D. Herisson, D. Neira, C. Fernand, P. Thony, D. Henry, S. Kremer, M. Polli, M. Guevremont, and A. Elazami, “Spectroscopic ellipsometry for lithography front-end level CD control: a complete analysis for production integration,” Proc. SPIE 5038, 264–273 (2003).
[CrossRef]

Purdy, M.

C. J. Raymond, M. Littau, R. Markle, and M. Purdy, “Scatterometry for shallow trench isolation (STI) process metrology,” Proc. SPIE 4344, 716–725 (2001).
[CrossRef]

Raymond, C. J.

C. J. Raymond, M. Littau, R. Markle, and M. Purdy, “Scatterometry for shallow trench isolation (STI) process metrology,” Proc. SPIE 4344, 716–725 (2001).
[CrossRef]

Russo, B.

R. M. Silver, R. Attota, M. Stocker, J. Jun, E. Marx, R. Larrabee, B. Russo, and M. Davidson, “Comparison of measured optical image profiles of silicon lines with two different theoretical models,” Proc. SPIE 4689, 409–429 (2002).
[CrossRef]

Ryabko, M. V.

Sendelbach, M.

A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
[CrossRef]

Shcherbakov, A. V.

Silver, R. M.

R. Attota, T. A. Germer, and R. M. Silver, “Through-focus scanning-optical-microscope imaging method for nanoscale dimensional analysis,” Opt. Lett. 33(17), 1990–1992 (2008).
[CrossRef] [PubMed]

R. Attota, R. M. Silver, M. R. Bishop, and R. G. Dixson, “Optical critical dimension measurement and illumination analysis using the through-focus focus metric,” Proc. SPIE 6152, 190–200 (2006).

R. Attota, R. M. Silver, M. T. Stocker, E. Marx, J.-S. J. Jun, M. P. Davidson, and R. D. Larrabee, “A new method to enhance overlay tool performance,” Proc. SPIE 5038, 428–436 (2003).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, J. Jun, E. Marx, R. Larrabee, B. Russo, and M. Davidson, “Comparison of measured optical image profiles of silicon lines with two different theoretical models,” Proc. SPIE 4689, 409–429 (2002).
[CrossRef]

Stocker, M.

R. M. Silver, R. Attota, M. Stocker, J. Jun, E. Marx, R. Larrabee, B. Russo, and M. Davidson, “Comparison of measured optical image profiles of silicon lines with two different theoretical models,” Proc. SPIE 4689, 409–429 (2002).
[CrossRef]

Stocker, M. T.

R. Attota, R. M. Silver, M. T. Stocker, E. Marx, J.-S. J. Jun, M. P. Davidson, and R. D. Larrabee, “A new method to enhance overlay tool performance,” Proc. SPIE 5038, 428–436 (2003).
[CrossRef]

Subramany, L.

A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
[CrossRef]

Taylor, J.

A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
[CrossRef]

Thony, P.

D. Herisson, D. Neira, C. Fernand, P. Thony, D. Henry, S. Kremer, M. Polli, M. Guevremont, and A. Elazami, “Spectroscopic ellipsometry for lithography front-end level CD control: a complete analysis for production integration,” Proc. SPIE 5038, 264–273 (2003).
[CrossRef]

Vaid, A.

A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
[CrossRef]

Opt. Express (1)

Opt. Lett. (2)

Proc. SPIE (6)

A. Vaid, L. Subramany, G. Iddawela, C. Ford, J. Allgair, G. Agrawal, J. Taylor, C. Hartig, B. C. Kang, C. Bozdog, M. Sendelbach, P. Isbester, and L. Issascharoff, “Implementation of hybrid metrology at HVM fab for 20 nm and beyond,” Proc. SPIE 8681, 868103 (2013).
[CrossRef]

D. Herisson, D. Neira, C. Fernand, P. Thony, D. Henry, S. Kremer, M. Polli, M. Guevremont, and A. Elazami, “Spectroscopic ellipsometry for lithography front-end level CD control: a complete analysis for production integration,” Proc. SPIE 5038, 264–273 (2003).
[CrossRef]

C. J. Raymond, M. Littau, R. Markle, and M. Purdy, “Scatterometry for shallow trench isolation (STI) process metrology,” Proc. SPIE 4344, 716–725 (2001).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, J. Jun, E. Marx, R. Larrabee, B. Russo, and M. Davidson, “Comparison of measured optical image profiles of silicon lines with two different theoretical models,” Proc. SPIE 4689, 409–429 (2002).
[CrossRef]

R. Attota, R. M. Silver, M. T. Stocker, E. Marx, J.-S. J. Jun, M. P. Davidson, and R. D. Larrabee, “A new method to enhance overlay tool performance,” Proc. SPIE 5038, 428–436 (2003).
[CrossRef]

R. Attota, R. M. Silver, M. R. Bishop, and R. G. Dixson, “Optical critical dimension measurement and illumination analysis using the through-focus focus metric,” Proc. SPIE 6152, 190–200 (2006).

Other (2)

I. T. R. S. Roadmap, http://www.itrs.net/Links/2006Update/2006UpdateFinal.htm

A. V. Arecchi, T. Messadi, and R. J. Koshel, Field Guide to Illumination (SPIE Press, 2007)

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Figures (5)

Fig. 1
Fig. 1

Experimental setup (right). Tunable light source setup (left).

Fig. 2
Fig. 2

SEM images of test objects.

Fig. 3
Fig. 3

Experimental setup calibration. (a) Normalized dependence of illumination intensity on grating angle value. (b) Sample focus offset dependence on grating angle value. The straight line is a linear fit to the measured data.

Fig. 4
Fig. 4

Test object measurements. (a) Normalized through-focus diffraction pattern obtained for an object with a 40 nm CD. (b) Normalized through-focus diffraction pattern for an object with a 50 nm CD. (c) Differential through-focus diffraction pattern for test objects with a 40 nm and 50 nm CD. (d) Normalized through-focus diffraction pattern obtained with a mechanical scanning approach.

Fig. 5
Fig. 5

Change in metric with CD value.

Metrics