Abstract

We have developed a set of techniques, referred to as scatterfield microscopy, in which the illumination is engineered in combination with appropriately designed metrology targets to extend the limits of image-based optical metrology. Previously we reported results from samples with sub-50-nm-sized features having pitches larger than the conventional Rayleigh resolution criterion, which resulted in images having edge contrast and elements of conventional imaging. In this paper we extend these methods to targets composed of features much denser than the conventional Rayleigh resolution criterion. For these applications, a new approach is presented that uses a combination of zero-order optical response and edge-based imaging. The approach is, however, more general and a more comprehensive set of analyses using theoretical methods is presented. This analysis gives a direct measure of the ultimate size and density of features that can be measured with these optical techniques. We present both experimental results and optical simulations using different electromagnetic scattering packages to evaluate the ultimate sensitivity and extensibility of these techniques.

© Optical Society of America

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  1. R. Attota, R. M. Silver, M. Bishop, E. Marx, J. Jun, M. Stocker, M. P. Davidson, and R. Larrabee, "Evaluation of new in-chip and arrayed line overlay target designs," Proc. SPIE 5375, 395-402 (2004).
    [CrossRef]
  2. J. Seligson, M. Adel, P. Izikson, V. Levinski, and D. Yaffe, "Target noise in overlay metrology," Proc. SPIE 5375, 403-412 (2004).
    [CrossRef]
  3. E. Solecky and J. Morillo, "Simultaneous critical dimension and overlay measurements on a SEM through target design for inline manufacturing lithography control," Proc. SPIE 5375, 41-50 (2004).
    [CrossRef]
  4. R. M. Silver, R. Attota, M. Stocker, M. Bishop, L. Howard, T. Germer, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical metrology," Proc. SPIE 5752, 67-79 (2005).
    [CrossRef]
  5. R. M. Silver, R. Attota, M. Stocker, M. Bishop, J. Jun, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical overlay metrology," Proc. SPIE 5375, 78-95 (2004).
    [CrossRef]
  6. R. Attota, R. M. Silver, T. Germer, M. Bishop, R. Larrabee, M. Stocker, and L. Howard, "Application of through-focus focus-metric analysis in high resolution optical microscopy," Proc. SPIE 5752, 1441-1449 (2005).
    [CrossRef]
  7. 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]
  8. M. Bishop, R. Silver, and B. Bunday, "The OMAG 3 reticle set," Tech Transfer #03074417A-ENG (International SEMATECH, 2004).
  9. C. M. Herzinger, B. Johs, W. A. McGahan, J. A. Woolam, and W. Paulson, "Ellipsometric determination of optical constants for silicon and thermally grown silicon dioxide via a multi-sample, multi-wavelength, multi-angle investigation," J. Appl. Phys. 83, 3323-3336 (1998).
    [CrossRef]
  10. R. M. Silver, B. Barnes, R. Attota, J. Jun, J. Filliben, J. Soto, M. Stocker, P. Lipscomb, E. Marx, H. Patrick, R. Dixson, and R. Larrabee, "The limits of image-based optical metrology," Proc. SPIE 6152, 6152OZ (2006).
    [CrossRef]
  11. E. Marx and J. Potzick, "Simulation of optical microscope images of photomask feature size measurements," in IEEE Antennas and Propagation Society International Symposium (IEEE, 2005), Vol. 3B, pp. 243-246.
  12. M. Davidson, B. H. Kleemann, and J. Bischoff, "A comparison between rigorous light scattering methods," Proc. SPIE 305, 606-619 (1997).
    [CrossRef]

2006 (1)

R. M. Silver, B. Barnes, R. Attota, J. Jun, J. Filliben, J. Soto, M. Stocker, P. Lipscomb, E. Marx, H. Patrick, R. Dixson, and R. Larrabee, "The limits of image-based optical metrology," Proc. SPIE 6152, 6152OZ (2006).
[CrossRef]

2005 (2)

R. Attota, R. M. Silver, T. Germer, M. Bishop, R. Larrabee, M. Stocker, and L. Howard, "Application of through-focus focus-metric analysis in high resolution optical microscopy," Proc. SPIE 5752, 1441-1449 (2005).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, L. Howard, T. Germer, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical metrology," Proc. SPIE 5752, 67-79 (2005).
[CrossRef]

2004 (4)

R. M. Silver, R. Attota, M. Stocker, M. Bishop, J. Jun, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical overlay metrology," Proc. SPIE 5375, 78-95 (2004).
[CrossRef]

R. Attota, R. M. Silver, M. Bishop, E. Marx, J. Jun, M. Stocker, M. P. Davidson, and R. Larrabee, "Evaluation of new in-chip and arrayed line overlay target designs," Proc. SPIE 5375, 395-402 (2004).
[CrossRef]

J. Seligson, M. Adel, P. Izikson, V. Levinski, and D. Yaffe, "Target noise in overlay metrology," Proc. SPIE 5375, 403-412 (2004).
[CrossRef]

E. Solecky and J. Morillo, "Simultaneous critical dimension and overlay measurements on a SEM through target design for inline manufacturing lithography control," Proc. SPIE 5375, 41-50 (2004).
[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]

1998 (1)

C. M. Herzinger, B. Johs, W. A. McGahan, J. A. Woolam, and W. Paulson, "Ellipsometric determination of optical constants for silicon and thermally grown silicon dioxide via a multi-sample, multi-wavelength, multi-angle investigation," J. Appl. Phys. 83, 3323-3336 (1998).
[CrossRef]

1997 (1)

M. Davidson, B. H. Kleemann, and J. Bischoff, "A comparison between rigorous light scattering methods," Proc. SPIE 305, 606-619 (1997).
[CrossRef]

Adel, M.

J. Seligson, M. Adel, P. Izikson, V. Levinski, and D. Yaffe, "Target noise in overlay metrology," Proc. SPIE 5375, 403-412 (2004).
[CrossRef]

Attota, R.

R. M. Silver, B. Barnes, R. Attota, J. Jun, J. Filliben, J. Soto, M. Stocker, P. Lipscomb, E. Marx, H. Patrick, R. Dixson, and R. Larrabee, "The limits of image-based optical metrology," Proc. SPIE 6152, 6152OZ (2006).
[CrossRef]

R. Attota, R. M. Silver, T. Germer, M. Bishop, R. Larrabee, M. Stocker, and L. Howard, "Application of through-focus focus-metric analysis in high resolution optical microscopy," Proc. SPIE 5752, 1441-1449 (2005).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, L. Howard, T. Germer, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical metrology," Proc. SPIE 5752, 67-79 (2005).
[CrossRef]

R. Attota, R. M. Silver, M. Bishop, E. Marx, J. Jun, M. Stocker, M. P. Davidson, and R. Larrabee, "Evaluation of new in-chip and arrayed line overlay target designs," Proc. SPIE 5375, 395-402 (2004).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, J. Jun, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical overlay metrology," Proc. SPIE 5375, 78-95 (2004).
[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]

Barnes, B.

R. M. Silver, B. Barnes, R. Attota, J. Jun, J. Filliben, J. Soto, M. Stocker, P. Lipscomb, E. Marx, H. Patrick, R. Dixson, and R. Larrabee, "The limits of image-based optical metrology," Proc. SPIE 6152, 6152OZ (2006).
[CrossRef]

Bischoff, J.

M. Davidson, B. H. Kleemann, and J. Bischoff, "A comparison between rigorous light scattering methods," Proc. SPIE 305, 606-619 (1997).
[CrossRef]

Bishop, M.

R. Attota, R. M. Silver, T. Germer, M. Bishop, R. Larrabee, M. Stocker, and L. Howard, "Application of through-focus focus-metric analysis in high resolution optical microscopy," Proc. SPIE 5752, 1441-1449 (2005).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, L. Howard, T. Germer, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical metrology," Proc. SPIE 5752, 67-79 (2005).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, J. Jun, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical overlay metrology," Proc. SPIE 5375, 78-95 (2004).
[CrossRef]

R. Attota, R. M. Silver, M. Bishop, E. Marx, J. Jun, M. Stocker, M. P. Davidson, and R. Larrabee, "Evaluation of new in-chip and arrayed line overlay target designs," Proc. SPIE 5375, 395-402 (2004).
[CrossRef]

M. Bishop, R. Silver, and B. Bunday, "The OMAG 3 reticle set," Tech Transfer #03074417A-ENG (International SEMATECH, 2004).

Bunday, B.

M. Bishop, R. Silver, and B. Bunday, "The OMAG 3 reticle set," Tech Transfer #03074417A-ENG (International SEMATECH, 2004).

Davidson, M.

R. M. Silver, R. Attota, M. Stocker, M. Bishop, L. Howard, T. Germer, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical metrology," Proc. SPIE 5752, 67-79 (2005).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, J. Jun, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical overlay metrology," Proc. SPIE 5375, 78-95 (2004).
[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]

M. Davidson, B. H. Kleemann, and J. Bischoff, "A comparison between rigorous light scattering methods," Proc. SPIE 305, 606-619 (1997).
[CrossRef]

Davidson, M. P.

R. Attota, R. M. Silver, M. Bishop, E. Marx, J. Jun, M. Stocker, M. P. Davidson, and R. Larrabee, "Evaluation of new in-chip and arrayed line overlay target designs," Proc. SPIE 5375, 395-402 (2004).
[CrossRef]

Dixson, R.

R. M. Silver, B. Barnes, R. Attota, J. Jun, J. Filliben, J. Soto, M. Stocker, P. Lipscomb, E. Marx, H. Patrick, R. Dixson, and R. Larrabee, "The limits of image-based optical metrology," Proc. SPIE 6152, 6152OZ (2006).
[CrossRef]

Filliben, J.

R. M. Silver, B. Barnes, R. Attota, J. Jun, J. Filliben, J. Soto, M. Stocker, P. Lipscomb, E. Marx, H. Patrick, R. Dixson, and R. Larrabee, "The limits of image-based optical metrology," Proc. SPIE 6152, 6152OZ (2006).
[CrossRef]

Germer, T.

R. Attota, R. M. Silver, T. Germer, M. Bishop, R. Larrabee, M. Stocker, and L. Howard, "Application of through-focus focus-metric analysis in high resolution optical microscopy," Proc. SPIE 5752, 1441-1449 (2005).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, L. Howard, T. Germer, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical metrology," Proc. SPIE 5752, 67-79 (2005).
[CrossRef]

Herzinger, C. M.

C. M. Herzinger, B. Johs, W. A. McGahan, J. A. Woolam, and W. Paulson, "Ellipsometric determination of optical constants for silicon and thermally grown silicon dioxide via a multi-sample, multi-wavelength, multi-angle investigation," J. Appl. Phys. 83, 3323-3336 (1998).
[CrossRef]

Howard, L.

R. Attota, R. M. Silver, T. Germer, M. Bishop, R. Larrabee, M. Stocker, and L. Howard, "Application of through-focus focus-metric analysis in high resolution optical microscopy," Proc. SPIE 5752, 1441-1449 (2005).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, L. Howard, T. Germer, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical metrology," Proc. SPIE 5752, 67-79 (2005).
[CrossRef]

Izikson, P.

J. Seligson, M. Adel, P. Izikson, V. Levinski, and D. Yaffe, "Target noise in overlay metrology," Proc. SPIE 5375, 403-412 (2004).
[CrossRef]

Johs, B.

C. M. Herzinger, B. Johs, W. A. McGahan, J. A. Woolam, and W. Paulson, "Ellipsometric determination of optical constants for silicon and thermally grown silicon dioxide via a multi-sample, multi-wavelength, multi-angle investigation," J. Appl. Phys. 83, 3323-3336 (1998).
[CrossRef]

Jun, J.

R. M. Silver, B. Barnes, R. Attota, J. Jun, J. Filliben, J. Soto, M. Stocker, P. Lipscomb, E. Marx, H. Patrick, R. Dixson, and R. Larrabee, "The limits of image-based optical metrology," Proc. SPIE 6152, 6152OZ (2006).
[CrossRef]

R. Attota, R. M. Silver, M. Bishop, E. Marx, J. Jun, M. Stocker, M. P. Davidson, and R. Larrabee, "Evaluation of new in-chip and arrayed line overlay target designs," Proc. SPIE 5375, 395-402 (2004).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, J. Jun, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical overlay metrology," Proc. SPIE 5375, 78-95 (2004).
[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]

Kleemann, B. H.

M. Davidson, B. H. Kleemann, and J. Bischoff, "A comparison between rigorous light scattering methods," Proc. SPIE 305, 606-619 (1997).
[CrossRef]

Larrabee, R.

R. M. Silver, B. Barnes, R. Attota, J. Jun, J. Filliben, J. Soto, M. Stocker, P. Lipscomb, E. Marx, H. Patrick, R. Dixson, and R. Larrabee, "The limits of image-based optical metrology," Proc. SPIE 6152, 6152OZ (2006).
[CrossRef]

R. Attota, R. M. Silver, T. Germer, M. Bishop, R. Larrabee, M. Stocker, and L. Howard, "Application of through-focus focus-metric analysis in high resolution optical microscopy," Proc. SPIE 5752, 1441-1449 (2005).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, L. Howard, T. Germer, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical metrology," Proc. SPIE 5752, 67-79 (2005).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, J. Jun, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical overlay metrology," Proc. SPIE 5375, 78-95 (2004).
[CrossRef]

R. Attota, R. M. Silver, M. Bishop, E. Marx, J. Jun, M. Stocker, M. P. Davidson, and R. Larrabee, "Evaluation of new in-chip and arrayed line overlay target designs," Proc. SPIE 5375, 395-402 (2004).
[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]

Levinski, V.

J. Seligson, M. Adel, P. Izikson, V. Levinski, and D. Yaffe, "Target noise in overlay metrology," Proc. SPIE 5375, 403-412 (2004).
[CrossRef]

Lipscomb, P.

R. M. Silver, B. Barnes, R. Attota, J. Jun, J. Filliben, J. Soto, M. Stocker, P. Lipscomb, E. Marx, H. Patrick, R. Dixson, and R. Larrabee, "The limits of image-based optical metrology," Proc. SPIE 6152, 6152OZ (2006).
[CrossRef]

Marx, E.

R. M. Silver, B. Barnes, R. Attota, J. Jun, J. Filliben, J. Soto, M. Stocker, P. Lipscomb, E. Marx, H. Patrick, R. Dixson, and R. Larrabee, "The limits of image-based optical metrology," Proc. SPIE 6152, 6152OZ (2006).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, L. Howard, T. Germer, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical metrology," Proc. SPIE 5752, 67-79 (2005).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, J. Jun, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical overlay metrology," Proc. SPIE 5375, 78-95 (2004).
[CrossRef]

R. Attota, R. M. Silver, M. Bishop, E. Marx, J. Jun, M. Stocker, M. P. Davidson, and R. Larrabee, "Evaluation of new in-chip and arrayed line overlay target designs," Proc. SPIE 5375, 395-402 (2004).
[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]

E. Marx and J. Potzick, "Simulation of optical microscope images of photomask feature size measurements," in IEEE Antennas and Propagation Society International Symposium (IEEE, 2005), Vol. 3B, pp. 243-246.

McGahan, W. A.

C. M. Herzinger, B. Johs, W. A. McGahan, J. A. Woolam, and W. Paulson, "Ellipsometric determination of optical constants for silicon and thermally grown silicon dioxide via a multi-sample, multi-wavelength, multi-angle investigation," J. Appl. Phys. 83, 3323-3336 (1998).
[CrossRef]

Morillo, J.

E. Solecky and J. Morillo, "Simultaneous critical dimension and overlay measurements on a SEM through target design for inline manufacturing lithography control," Proc. SPIE 5375, 41-50 (2004).
[CrossRef]

Patrick, H.

R. M. Silver, B. Barnes, R. Attota, J. Jun, J. Filliben, J. Soto, M. Stocker, P. Lipscomb, E. Marx, H. Patrick, R. Dixson, and R. Larrabee, "The limits of image-based optical metrology," Proc. SPIE 6152, 6152OZ (2006).
[CrossRef]

Paulson, W.

C. M. Herzinger, B. Johs, W. A. McGahan, J. A. Woolam, and W. Paulson, "Ellipsometric determination of optical constants for silicon and thermally grown silicon dioxide via a multi-sample, multi-wavelength, multi-angle investigation," J. Appl. Phys. 83, 3323-3336 (1998).
[CrossRef]

Potzick, J.

E. Marx and J. Potzick, "Simulation of optical microscope images of photomask feature size measurements," in IEEE Antennas and Propagation Society International Symposium (IEEE, 2005), Vol. 3B, pp. 243-246.

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]

Seligson, J.

J. Seligson, M. Adel, P. Izikson, V. Levinski, and D. Yaffe, "Target noise in overlay metrology," Proc. SPIE 5375, 403-412 (2004).
[CrossRef]

Silver, R.

M. Bishop, R. Silver, and B. Bunday, "The OMAG 3 reticle set," Tech Transfer #03074417A-ENG (International SEMATECH, 2004).

Silver, R. M.

R. M. Silver, B. Barnes, R. Attota, J. Jun, J. Filliben, J. Soto, M. Stocker, P. Lipscomb, E. Marx, H. Patrick, R. Dixson, and R. Larrabee, "The limits of image-based optical metrology," Proc. SPIE 6152, 6152OZ (2006).
[CrossRef]

R. Attota, R. M. Silver, T. Germer, M. Bishop, R. Larrabee, M. Stocker, and L. Howard, "Application of through-focus focus-metric analysis in high resolution optical microscopy," Proc. SPIE 5752, 1441-1449 (2005).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, L. Howard, T. Germer, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical metrology," Proc. SPIE 5752, 67-79 (2005).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, J. Jun, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical overlay metrology," Proc. SPIE 5375, 78-95 (2004).
[CrossRef]

R. Attota, R. M. Silver, M. Bishop, E. Marx, J. Jun, M. Stocker, M. P. Davidson, and R. Larrabee, "Evaluation of new in-chip and arrayed line overlay target designs," Proc. SPIE 5375, 395-402 (2004).
[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]

Solecky, E.

E. Solecky and J. Morillo, "Simultaneous critical dimension and overlay measurements on a SEM through target design for inline manufacturing lithography control," Proc. SPIE 5375, 41-50 (2004).
[CrossRef]

Soto, J.

R. M. Silver, B. Barnes, R. Attota, J. Jun, J. Filliben, J. Soto, M. Stocker, P. Lipscomb, E. Marx, H. Patrick, R. Dixson, and R. Larrabee, "The limits of image-based optical metrology," Proc. SPIE 6152, 6152OZ (2006).
[CrossRef]

Stocker, M.

R. M. Silver, B. Barnes, R. Attota, J. Jun, J. Filliben, J. Soto, M. Stocker, P. Lipscomb, E. Marx, H. Patrick, R. Dixson, and R. Larrabee, "The limits of image-based optical metrology," Proc. SPIE 6152, 6152OZ (2006).
[CrossRef]

R. Attota, R. M. Silver, T. Germer, M. Bishop, R. Larrabee, M. Stocker, and L. Howard, "Application of through-focus focus-metric analysis in high resolution optical microscopy," Proc. SPIE 5752, 1441-1449 (2005).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, L. Howard, T. Germer, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical metrology," Proc. SPIE 5752, 67-79 (2005).
[CrossRef]

R. Attota, R. M. Silver, M. Bishop, E. Marx, J. Jun, M. Stocker, M. P. Davidson, and R. Larrabee, "Evaluation of new in-chip and arrayed line overlay target designs," Proc. SPIE 5375, 395-402 (2004).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, J. Jun, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical overlay metrology," Proc. SPIE 5375, 78-95 (2004).
[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]

Woolam, J. A.

C. M. Herzinger, B. Johs, W. A. McGahan, J. A. Woolam, and W. Paulson, "Ellipsometric determination of optical constants for silicon and thermally grown silicon dioxide via a multi-sample, multi-wavelength, multi-angle investigation," J. Appl. Phys. 83, 3323-3336 (1998).
[CrossRef]

Yaffe, D.

J. Seligson, M. Adel, P. Izikson, V. Levinski, and D. Yaffe, "Target noise in overlay metrology," Proc. SPIE 5375, 403-412 (2004).
[CrossRef]

J. Appl. Phys. (1)

C. M. Herzinger, B. Johs, W. A. McGahan, J. A. Woolam, and W. Paulson, "Ellipsometric determination of optical constants for silicon and thermally grown silicon dioxide via a multi-sample, multi-wavelength, multi-angle investigation," J. Appl. Phys. 83, 3323-3336 (1998).
[CrossRef]

Proc. SPIE (9)

R. M. Silver, B. Barnes, R. Attota, J. Jun, J. Filliben, J. Soto, M. Stocker, P. Lipscomb, E. Marx, H. Patrick, R. Dixson, and R. Larrabee, "The limits of image-based optical metrology," Proc. SPIE 6152, 6152OZ (2006).
[CrossRef]

M. Davidson, B. H. Kleemann, and J. Bischoff, "A comparison between rigorous light scattering methods," Proc. SPIE 305, 606-619 (1997).
[CrossRef]

R. Attota, R. M. Silver, M. Bishop, E. Marx, J. Jun, M. Stocker, M. P. Davidson, and R. Larrabee, "Evaluation of new in-chip and arrayed line overlay target designs," Proc. SPIE 5375, 395-402 (2004).
[CrossRef]

J. Seligson, M. Adel, P. Izikson, V. Levinski, and D. Yaffe, "Target noise in overlay metrology," Proc. SPIE 5375, 403-412 (2004).
[CrossRef]

E. Solecky and J. Morillo, "Simultaneous critical dimension and overlay measurements on a SEM through target design for inline manufacturing lithography control," Proc. SPIE 5375, 41-50 (2004).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, L. Howard, T. Germer, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical metrology," Proc. SPIE 5752, 67-79 (2005).
[CrossRef]

R. M. Silver, R. Attota, M. Stocker, M. Bishop, J. Jun, E. Marx, M. Davidson, and R. Larrabee, "High-resolution optical overlay metrology," Proc. SPIE 5375, 78-95 (2004).
[CrossRef]

R. Attota, R. M. Silver, T. Germer, M. Bishop, R. Larrabee, M. Stocker, and L. Howard, "Application of through-focus focus-metric analysis in high resolution optical microscopy," Proc. SPIE 5752, 1441-1449 (2005).
[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]

Other (2)

M. Bishop, R. Silver, and B. Bunday, "The OMAG 3 reticle set," Tech Transfer #03074417A-ENG (International SEMATECH, 2004).

E. Marx and J. Potzick, "Simulation of optical microscope images of photomask feature size measurements," in IEEE Antennas and Propagation Society International Symposium (IEEE, 2005), Vol. 3B, pp. 243-246.

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Figures (9)

Fig. 1
Fig. 1

(Color online) Simplified schematic of the optical configuration. The upper figure is a conceptual drawing of the illumination path demonstrating how access to a conjugate back focal plane enables selective angular illumination or more general illumination engineering. The lower part of the figure shows the layout of the laboratory implementation.

Fig. 2
Fig. 2

(Color online) Background intensity data is acquired for each image as a function of angle, plotted in the upper panel for the unpolarized case and both polarizations. A point-by-point matrix correction is used to normalize the angle-resolved background data to account for the angle-dependent intensity variation. The reflected light is then normalized using the theoretical angle-dependent silicon reflectivity curves shown in the lower part of the figure. This approach is essential to normalize the angle-resolved data correctly so it can be compared to simulations.

Fig. 3
Fig. 3

Experimental data before and after normalization. TE polarization is on top and TM is shown on the bottom. The vertical axes are units of normalized intensity and the horizontal axes are illumination angle in degrees. The data show good sensitivity to nanometer changes in linewidth. The data on the left are presented prior to normalization and show good sensitivity to small changes in line width. The data on the right side have been normalized to the background. The normalization process changes the dynamic range and results in the apparent loss of sensitivity, which can be easily regained by focusing on a smaller range of angles. The normalization process is essential when comparing theory to experiment.

Fig. 4
Fig. 4

(Color online) Data on the left are simulation results and the right side shows experimental results. The vertical axes are units of normalized intensity. The simulations span the range of CD values measured with the AFM and SEM. The experimental data are silicon corrected and compare most favorably with the simulations between 145 and 155 nm . Subsequent work with higher-resolution simulation steps confirms these results.

Fig. 5
Fig. 5

(a) Schematic of the target designs. This is one example of several variations of this design. (b) Image and a set of profiles for a target, which reflects higher-order optical content. On the wafer there are five target pitches and three offset values, 0, + / 10 nm .

Fig. 6
Fig. 6

(Color online) An image with zero-order scattering characteristics for all targets is shown on the left. The data windows from the image are plotted on the right side. This is a standard target with no designed-in CD variation. The intensity oscillations, observed as the four bars in the top row and bottom row of targets, is an edge-based interference effect. This is the result of the optical proximity of the array edges, which interfere with one another. Larger target arrays with the same linewidth dimensions and spacing demonstrate the expected constant intensity in the central array region.

Fig. 7
Fig. 7

(Color online) Different panels showing the image as a function of illumination angle, from normal incidence to 60° in 20° increments. The vertical axes are normalized intensity and the horizontal axes are lateral position in micrometers. At the high illumination angles, the higher-order diffraction orders are rocked into the collection optics. A dipole or alternative symmetric illumination can yield symmetric profiles or overlay measurements with higher-order optical content, which would otherwise only show zero-order response.

Fig. 8
Fig. 8

(Color online) Normalized intensity versus position from three windows in a linearity target having only zero-order response form the eight line target arrays. Simulation results are shown on the bottom and experimental data on top. The mean intensity from the central part of each profile can be analyzed for sensitivity to changes in CD. The experimental results and simulations show the same nominal change in average intensity.

Fig. 9
Fig. 9

(Color online) Angle-resolved intensity plots for the center locations in the target patterns. The upper set of panels are for targets with no CD variations designed in and the lower set show 5 nm increments in CD across the target. The p polarization shows the best sensitivity. These are complete angle scan data sets.

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