Abstract

Optical microscopy is sensitive both to arrays of nanoscale features and to their imperfections. Optimizing scattered electromagnetic field intensities from deep sub-wavelength nanometer scale structures represents an important element of optical metrology. Current, well-established optical methods used to identify defects in semiconductor patterning are in jeopardy by upcoming sub-20 nm device dimensions. A novel volumetric analysis for processing focus-resolved images of defects is presented using simulated and experimental examples. This new method allows defects as narrow as (16 ± 2) nm (k = 1) to be revealed using 193 nm light with focus and illumination conditions optimized for three-dimensional data analysis. Quantitative metrics to compare two-dimensional and three-dimensional imaging indicate possible fourfold improvements in sensitivity using these methods.

© 2013 Optical Society of America

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References

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  1. C. J. Raymond, M. R. Murnane, S. Sohail, H. Naqvi, and J. R. McNeil, “Metrology of subwavelength photoresist gratings using optical scatterometry,” J. Vac. Sci. Technol. B13(4), 1484–1495 (1995).
    [CrossRef]
  2. J. Qin, R. M. Silver, B. M. Barnes, H. Zhou, and F. Goasmat, “Fourier domain optical tool normalization for quantitative parametric image reconstruction,” Appl. Opt.52(26), 6512–6522 (2013).
    [CrossRef] [PubMed]
  3. T. F. Crimmins, “Defect metrology challenges at the 11nm node and beyond,” Proc. SPIE7638, 76380H, 76380H-12 (2010).
    [CrossRef]
  4. T. F. Crimmins, “Wafer noise models for defect inspection,” Proc. SPIE7971, 79710E, 79710E-6 (2011).
    [CrossRef]
  5. R. M. Silver, B. M. Barnes, R. Attota, J. S. Jun, M. T. Stocker, E. Marx, and H. J. Patrick, “Scatterfield microscopy for extending the limits of image-based optical metrology,” Appl. Opt.46(20), 4248–4257 (2007).
    [CrossRef] [PubMed]
  6. B. M. Barnes, Y. J. Sohn, F. Goasmat, H. Zhou, R. M. Silver, and A. Arceo, “Scatterfield microscopy of 22 nm node patterned defects using visible and DUV light,” Proc. SPIE8324, 83240F, 83240F-11 (2012).
    [CrossRef]
  7. V. Tympel, M. Schaaf, and B. Srocka, “3D defect detection using optical wide-field microscopy,” Proc. SPIE6616, 66161D, 66161D-7 (2007).
    [CrossRef]
  8. K. H. Kim, J. G. Jo, M. C. Park, B. K. Ju, S. Cho, and J. Y. Son, “Coherent scattering stereoscopic microscopy for mask inspection of extreme ultra-violet lithography,” Proc. SPIE8738, 87380Z, 87380Z-6 (2013).
    [CrossRef]
  9. R. Zhou, C. Edwards, A. Arbabi, G. Popescu, and L. L. Goddard, “Detecting 20 nm wide defects in large area nanopatterns using optical interferometric microscopy,” Nano Lett.13(8), 3716–3721 (2013).
    [CrossRef] [PubMed]
  10. A. Taflove, “Application of the finite-difference time-domain method to sinusoidal steady-state electromagnetic-penetration problems,” IEEE Trans. Electromagn. Compat.EMC-22(3), 191–202 (1980).
    [CrossRef]
  11. Y. J. Sohn, R. Quintanilha, B. M. Barnes, and R. M. Silver, “193 nm angle-resolved scatterfield microscope for semiconductor metrology,” Proc. SPIE7405, 74050R, 74050R-8 (2009).
    [CrossRef]
  12. G. D. Evangelidis and E. Z. Psarakis, “Parametric image alignment using enhanced correlation coefficient maximization,” IEEE Trans. Pattern Anal. Mach. Intell.30(10), 1858–1865 (2008).
    [CrossRef] [PubMed]
  13. J. B. Poline, K. J. Worsley, A. C. Evans, and K. J. Friston, “Combining Spatial Extent and Peak Intensity to Test for Activations in Functional Imaging,” Neuroimage5(2), 83–96 (1997).
    [CrossRef] [PubMed]

2013 (3)

K. H. Kim, J. G. Jo, M. C. Park, B. K. Ju, S. Cho, and J. Y. Son, “Coherent scattering stereoscopic microscopy for mask inspection of extreme ultra-violet lithography,” Proc. SPIE8738, 87380Z, 87380Z-6 (2013).
[CrossRef]

R. Zhou, C. Edwards, A. Arbabi, G. Popescu, and L. L. Goddard, “Detecting 20 nm wide defects in large area nanopatterns using optical interferometric microscopy,” Nano Lett.13(8), 3716–3721 (2013).
[CrossRef] [PubMed]

J. Qin, R. M. Silver, B. M. Barnes, H. Zhou, and F. Goasmat, “Fourier domain optical tool normalization for quantitative parametric image reconstruction,” Appl. Opt.52(26), 6512–6522 (2013).
[CrossRef] [PubMed]

2012 (1)

B. M. Barnes, Y. J. Sohn, F. Goasmat, H. Zhou, R. M. Silver, and A. Arceo, “Scatterfield microscopy of 22 nm node patterned defects using visible and DUV light,” Proc. SPIE8324, 83240F, 83240F-11 (2012).
[CrossRef]

2011 (1)

T. F. Crimmins, “Wafer noise models for defect inspection,” Proc. SPIE7971, 79710E, 79710E-6 (2011).
[CrossRef]

2010 (1)

T. F. Crimmins, “Defect metrology challenges at the 11nm node and beyond,” Proc. SPIE7638, 76380H, 76380H-12 (2010).
[CrossRef]

2009 (1)

Y. J. Sohn, R. Quintanilha, B. M. Barnes, and R. M. Silver, “193 nm angle-resolved scatterfield microscope for semiconductor metrology,” Proc. SPIE7405, 74050R, 74050R-8 (2009).
[CrossRef]

2008 (1)

G. D. Evangelidis and E. Z. Psarakis, “Parametric image alignment using enhanced correlation coefficient maximization,” IEEE Trans. Pattern Anal. Mach. Intell.30(10), 1858–1865 (2008).
[CrossRef] [PubMed]

2007 (2)

1997 (1)

J. B. Poline, K. J. Worsley, A. C. Evans, and K. J. Friston, “Combining Spatial Extent and Peak Intensity to Test for Activations in Functional Imaging,” Neuroimage5(2), 83–96 (1997).
[CrossRef] [PubMed]

1995 (1)

C. J. Raymond, M. R. Murnane, S. Sohail, H. Naqvi, and J. R. McNeil, “Metrology of subwavelength photoresist gratings using optical scatterometry,” J. Vac. Sci. Technol. B13(4), 1484–1495 (1995).
[CrossRef]

1980 (1)

A. Taflove, “Application of the finite-difference time-domain method to sinusoidal steady-state electromagnetic-penetration problems,” IEEE Trans. Electromagn. Compat.EMC-22(3), 191–202 (1980).
[CrossRef]

Arbabi, A.

R. Zhou, C. Edwards, A. Arbabi, G. Popescu, and L. L. Goddard, “Detecting 20 nm wide defects in large area nanopatterns using optical interferometric microscopy,” Nano Lett.13(8), 3716–3721 (2013).
[CrossRef] [PubMed]

Arceo, A.

B. M. Barnes, Y. J. Sohn, F. Goasmat, H. Zhou, R. M. Silver, and A. Arceo, “Scatterfield microscopy of 22 nm node patterned defects using visible and DUV light,” Proc. SPIE8324, 83240F, 83240F-11 (2012).
[CrossRef]

Attota, R.

Barnes, B. M.

J. Qin, R. M. Silver, B. M. Barnes, H. Zhou, and F. Goasmat, “Fourier domain optical tool normalization for quantitative parametric image reconstruction,” Appl. Opt.52(26), 6512–6522 (2013).
[CrossRef] [PubMed]

B. M. Barnes, Y. J. Sohn, F. Goasmat, H. Zhou, R. M. Silver, and A. Arceo, “Scatterfield microscopy of 22 nm node patterned defects using visible and DUV light,” Proc. SPIE8324, 83240F, 83240F-11 (2012).
[CrossRef]

Y. J. Sohn, R. Quintanilha, B. M. Barnes, and R. M. Silver, “193 nm angle-resolved scatterfield microscope for semiconductor metrology,” Proc. SPIE7405, 74050R, 74050R-8 (2009).
[CrossRef]

R. M. Silver, B. M. Barnes, R. Attota, J. S. Jun, M. T. Stocker, E. Marx, and H. J. Patrick, “Scatterfield microscopy for extending the limits of image-based optical metrology,” Appl. Opt.46(20), 4248–4257 (2007).
[CrossRef] [PubMed]

Cho, S.

K. H. Kim, J. G. Jo, M. C. Park, B. K. Ju, S. Cho, and J. Y. Son, “Coherent scattering stereoscopic microscopy for mask inspection of extreme ultra-violet lithography,” Proc. SPIE8738, 87380Z, 87380Z-6 (2013).
[CrossRef]

Crimmins, T. F.

T. F. Crimmins, “Wafer noise models for defect inspection,” Proc. SPIE7971, 79710E, 79710E-6 (2011).
[CrossRef]

T. F. Crimmins, “Defect metrology challenges at the 11nm node and beyond,” Proc. SPIE7638, 76380H, 76380H-12 (2010).
[CrossRef]

Edwards, C.

R. Zhou, C. Edwards, A. Arbabi, G. Popescu, and L. L. Goddard, “Detecting 20 nm wide defects in large area nanopatterns using optical interferometric microscopy,” Nano Lett.13(8), 3716–3721 (2013).
[CrossRef] [PubMed]

Evangelidis, G. D.

G. D. Evangelidis and E. Z. Psarakis, “Parametric image alignment using enhanced correlation coefficient maximization,” IEEE Trans. Pattern Anal. Mach. Intell.30(10), 1858–1865 (2008).
[CrossRef] [PubMed]

Evans, A. C.

J. B. Poline, K. J. Worsley, A. C. Evans, and K. J. Friston, “Combining Spatial Extent and Peak Intensity to Test for Activations in Functional Imaging,” Neuroimage5(2), 83–96 (1997).
[CrossRef] [PubMed]

Friston, K. J.

J. B. Poline, K. J. Worsley, A. C. Evans, and K. J. Friston, “Combining Spatial Extent and Peak Intensity to Test for Activations in Functional Imaging,” Neuroimage5(2), 83–96 (1997).
[CrossRef] [PubMed]

Goasmat, F.

J. Qin, R. M. Silver, B. M. Barnes, H. Zhou, and F. Goasmat, “Fourier domain optical tool normalization for quantitative parametric image reconstruction,” Appl. Opt.52(26), 6512–6522 (2013).
[CrossRef] [PubMed]

B. M. Barnes, Y. J. Sohn, F. Goasmat, H. Zhou, R. M. Silver, and A. Arceo, “Scatterfield microscopy of 22 nm node patterned defects using visible and DUV light,” Proc. SPIE8324, 83240F, 83240F-11 (2012).
[CrossRef]

Goddard, L. L.

R. Zhou, C. Edwards, A. Arbabi, G. Popescu, and L. L. Goddard, “Detecting 20 nm wide defects in large area nanopatterns using optical interferometric microscopy,” Nano Lett.13(8), 3716–3721 (2013).
[CrossRef] [PubMed]

Jo, J. G.

K. H. Kim, J. G. Jo, M. C. Park, B. K. Ju, S. Cho, and J. Y. Son, “Coherent scattering stereoscopic microscopy for mask inspection of extreme ultra-violet lithography,” Proc. SPIE8738, 87380Z, 87380Z-6 (2013).
[CrossRef]

Ju, B. K.

K. H. Kim, J. G. Jo, M. C. Park, B. K. Ju, S. Cho, and J. Y. Son, “Coherent scattering stereoscopic microscopy for mask inspection of extreme ultra-violet lithography,” Proc. SPIE8738, 87380Z, 87380Z-6 (2013).
[CrossRef]

Jun, J. S.

Kim, K. H.

K. H. Kim, J. G. Jo, M. C. Park, B. K. Ju, S. Cho, and J. Y. Son, “Coherent scattering stereoscopic microscopy for mask inspection of extreme ultra-violet lithography,” Proc. SPIE8738, 87380Z, 87380Z-6 (2013).
[CrossRef]

Marx, E.

McNeil, J. R.

C. J. Raymond, M. R. Murnane, S. Sohail, H. Naqvi, and J. R. McNeil, “Metrology of subwavelength photoresist gratings using optical scatterometry,” J. Vac. Sci. Technol. B13(4), 1484–1495 (1995).
[CrossRef]

Murnane, M. R.

C. J. Raymond, M. R. Murnane, S. Sohail, H. Naqvi, and J. R. McNeil, “Metrology of subwavelength photoresist gratings using optical scatterometry,” J. Vac. Sci. Technol. B13(4), 1484–1495 (1995).
[CrossRef]

Naqvi, H.

C. J. Raymond, M. R. Murnane, S. Sohail, H. Naqvi, and J. R. McNeil, “Metrology of subwavelength photoresist gratings using optical scatterometry,” J. Vac. Sci. Technol. B13(4), 1484–1495 (1995).
[CrossRef]

Park, M. C.

K. H. Kim, J. G. Jo, M. C. Park, B. K. Ju, S. Cho, and J. Y. Son, “Coherent scattering stereoscopic microscopy for mask inspection of extreme ultra-violet lithography,” Proc. SPIE8738, 87380Z, 87380Z-6 (2013).
[CrossRef]

Patrick, H. J.

Poline, J. B.

J. B. Poline, K. J. Worsley, A. C. Evans, and K. J. Friston, “Combining Spatial Extent and Peak Intensity to Test for Activations in Functional Imaging,” Neuroimage5(2), 83–96 (1997).
[CrossRef] [PubMed]

Popescu, G.

R. Zhou, C. Edwards, A. Arbabi, G. Popescu, and L. L. Goddard, “Detecting 20 nm wide defects in large area nanopatterns using optical interferometric microscopy,” Nano Lett.13(8), 3716–3721 (2013).
[CrossRef] [PubMed]

Psarakis, E. Z.

G. D. Evangelidis and E. Z. Psarakis, “Parametric image alignment using enhanced correlation coefficient maximization,” IEEE Trans. Pattern Anal. Mach. Intell.30(10), 1858–1865 (2008).
[CrossRef] [PubMed]

Qin, J.

Quintanilha, R.

Y. J. Sohn, R. Quintanilha, B. M. Barnes, and R. M. Silver, “193 nm angle-resolved scatterfield microscope for semiconductor metrology,” Proc. SPIE7405, 74050R, 74050R-8 (2009).
[CrossRef]

Raymond, C. J.

C. J. Raymond, M. R. Murnane, S. Sohail, H. Naqvi, and J. R. McNeil, “Metrology of subwavelength photoresist gratings using optical scatterometry,” J. Vac. Sci. Technol. B13(4), 1484–1495 (1995).
[CrossRef]

Schaaf, M.

V. Tympel, M. Schaaf, and B. Srocka, “3D defect detection using optical wide-field microscopy,” Proc. SPIE6616, 66161D, 66161D-7 (2007).
[CrossRef]

Silver, R. M.

J. Qin, R. M. Silver, B. M. Barnes, H. Zhou, and F. Goasmat, “Fourier domain optical tool normalization for quantitative parametric image reconstruction,” Appl. Opt.52(26), 6512–6522 (2013).
[CrossRef] [PubMed]

B. M. Barnes, Y. J. Sohn, F. Goasmat, H. Zhou, R. M. Silver, and A. Arceo, “Scatterfield microscopy of 22 nm node patterned defects using visible and DUV light,” Proc. SPIE8324, 83240F, 83240F-11 (2012).
[CrossRef]

Y. J. Sohn, R. Quintanilha, B. M. Barnes, and R. M. Silver, “193 nm angle-resolved scatterfield microscope for semiconductor metrology,” Proc. SPIE7405, 74050R, 74050R-8 (2009).
[CrossRef]

R. M. Silver, B. M. Barnes, R. Attota, J. S. Jun, M. T. Stocker, E. Marx, and H. J. Patrick, “Scatterfield microscopy for extending the limits of image-based optical metrology,” Appl. Opt.46(20), 4248–4257 (2007).
[CrossRef] [PubMed]

Sohail, S.

C. J. Raymond, M. R. Murnane, S. Sohail, H. Naqvi, and J. R. McNeil, “Metrology of subwavelength photoresist gratings using optical scatterometry,” J. Vac. Sci. Technol. B13(4), 1484–1495 (1995).
[CrossRef]

Sohn, Y. J.

B. M. Barnes, Y. J. Sohn, F. Goasmat, H. Zhou, R. M. Silver, and A. Arceo, “Scatterfield microscopy of 22 nm node patterned defects using visible and DUV light,” Proc. SPIE8324, 83240F, 83240F-11 (2012).
[CrossRef]

Y. J. Sohn, R. Quintanilha, B. M. Barnes, and R. M. Silver, “193 nm angle-resolved scatterfield microscope for semiconductor metrology,” Proc. SPIE7405, 74050R, 74050R-8 (2009).
[CrossRef]

Son, J. Y.

K. H. Kim, J. G. Jo, M. C. Park, B. K. Ju, S. Cho, and J. Y. Son, “Coherent scattering stereoscopic microscopy for mask inspection of extreme ultra-violet lithography,” Proc. SPIE8738, 87380Z, 87380Z-6 (2013).
[CrossRef]

Srocka, B.

V. Tympel, M. Schaaf, and B. Srocka, “3D defect detection using optical wide-field microscopy,” Proc. SPIE6616, 66161D, 66161D-7 (2007).
[CrossRef]

Stocker, M. T.

Taflove, A.

A. Taflove, “Application of the finite-difference time-domain method to sinusoidal steady-state electromagnetic-penetration problems,” IEEE Trans. Electromagn. Compat.EMC-22(3), 191–202 (1980).
[CrossRef]

Tympel, V.

V. Tympel, M. Schaaf, and B. Srocka, “3D defect detection using optical wide-field microscopy,” Proc. SPIE6616, 66161D, 66161D-7 (2007).
[CrossRef]

Worsley, K. J.

J. B. Poline, K. J. Worsley, A. C. Evans, and K. J. Friston, “Combining Spatial Extent and Peak Intensity to Test for Activations in Functional Imaging,” Neuroimage5(2), 83–96 (1997).
[CrossRef] [PubMed]

Zhou, H.

J. Qin, R. M. Silver, B. M. Barnes, H. Zhou, and F. Goasmat, “Fourier domain optical tool normalization for quantitative parametric image reconstruction,” Appl. Opt.52(26), 6512–6522 (2013).
[CrossRef] [PubMed]

B. M. Barnes, Y. J. Sohn, F. Goasmat, H. Zhou, R. M. Silver, and A. Arceo, “Scatterfield microscopy of 22 nm node patterned defects using visible and DUV light,” Proc. SPIE8324, 83240F, 83240F-11 (2012).
[CrossRef]

Zhou, R.

R. Zhou, C. Edwards, A. Arbabi, G. Popescu, and L. L. Goddard, “Detecting 20 nm wide defects in large area nanopatterns using optical interferometric microscopy,” Nano Lett.13(8), 3716–3721 (2013).
[CrossRef] [PubMed]

Appl. Opt. (2)

IEEE Trans. Electromagn. Compat. (1)

A. Taflove, “Application of the finite-difference time-domain method to sinusoidal steady-state electromagnetic-penetration problems,” IEEE Trans. Electromagn. Compat.EMC-22(3), 191–202 (1980).
[CrossRef]

IEEE Trans. Pattern Anal. Mach. Intell. (1)

G. D. Evangelidis and E. Z. Psarakis, “Parametric image alignment using enhanced correlation coefficient maximization,” IEEE Trans. Pattern Anal. Mach. Intell.30(10), 1858–1865 (2008).
[CrossRef] [PubMed]

J. Vac. Sci. Technol. B (1)

C. J. Raymond, M. R. Murnane, S. Sohail, H. Naqvi, and J. R. McNeil, “Metrology of subwavelength photoresist gratings using optical scatterometry,” J. Vac. Sci. Technol. B13(4), 1484–1495 (1995).
[CrossRef]

Nano Lett. (1)

R. Zhou, C. Edwards, A. Arbabi, G. Popescu, and L. L. Goddard, “Detecting 20 nm wide defects in large area nanopatterns using optical interferometric microscopy,” Nano Lett.13(8), 3716–3721 (2013).
[CrossRef] [PubMed]

Neuroimage (1)

J. B. Poline, K. J. Worsley, A. C. Evans, and K. J. Friston, “Combining Spatial Extent and Peak Intensity to Test for Activations in Functional Imaging,” Neuroimage5(2), 83–96 (1997).
[CrossRef] [PubMed]

Proc. SPIE (6)

T. F. Crimmins, “Defect metrology challenges at the 11nm node and beyond,” Proc. SPIE7638, 76380H, 76380H-12 (2010).
[CrossRef]

T. F. Crimmins, “Wafer noise models for defect inspection,” Proc. SPIE7971, 79710E, 79710E-6 (2011).
[CrossRef]

Y. J. Sohn, R. Quintanilha, B. M. Barnes, and R. M. Silver, “193 nm angle-resolved scatterfield microscope for semiconductor metrology,” Proc. SPIE7405, 74050R, 74050R-8 (2009).
[CrossRef]

B. M. Barnes, Y. J. Sohn, F. Goasmat, H. Zhou, R. M. Silver, and A. Arceo, “Scatterfield microscopy of 22 nm node patterned defects using visible and DUV light,” Proc. SPIE8324, 83240F, 83240F-11 (2012).
[CrossRef]

V. Tympel, M. Schaaf, and B. Srocka, “3D defect detection using optical wide-field microscopy,” Proc. SPIE6616, 66161D, 66161D-7 (2007).
[CrossRef]

K. H. Kim, J. G. Jo, M. C. Park, B. K. Ju, S. Cho, and J. Y. Son, “Coherent scattering stereoscopic microscopy for mask inspection of extreme ultra-violet lithography,” Proc. SPIE8738, 87380Z, 87380Z-6 (2013).
[CrossRef]

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Figures (8)

Fig. 1
Fig. 1

Scanning electron micrographs of patterned defects. a) “Bx” bridge. b) “By” bridge. Insets show schematics for simulation. c) Axis, angle definitions relative to the patterning. The heights of the lines are nominally 35 nm.

Fig. 2
Fig. 2

Orientation of full-field and dipole illumination relative to the patterned structure. a) Annular full-field illumination b) 0° and 90° dipole orientations with respect to the patterned lines.

Fig. 3
Fig. 3

Two-dimensional absolute-value difference images for selected dies and defects. Defect widths as measured using SEM are decreasing from left to right, with defect width values specified in Table 1.

Fig. 4
Fig. 4

Steps in generating three-dimensional defect images. a) Selected 2D simulations performed through focus. b) The full simulation set stacked into a volumetric matrix c) Experimental data filtered using a 3D fast Fourier transform (FFT).

Fig. 5
Fig. 5

Volumetric analysis for defect detection. a) Correlation of experimental reference and defect matrices using a 3D correlation algorithm. b) Simulated difference volume with cut-out showing the optical signature of a defect. c) Application of intensity and size thresholds differentiate the defect’s primary optical signal (green) from random and correlated noise (red).

Fig. 6
Fig. 6

Polarization-dependent detection of simulated defects in the presence of noise. a) “Bx” defect, x pol. b) “Bx” defect, y pol. c) “By” defect, x pol. d) “By” defect, y pol.

Fig. 7
Fig. 7

Renderings of a volumetrically processed experimental difference volume with two copies of a defect signature identified. Defect corresponds to Fig. 3(d). a) 3D isometric view, b) YZ projection, c) XY projection, and d) XY slice through the centroid of one of the defects (green) and noise (red) identified at that height. Area thresholding can remove much of the noise in this plane, but unique isolation of the intentional defect in 2D is frustrated by the noise.

Fig. 8
Fig. 8

Signal to noise analysis of the volumetric defect detection method varying the intensity and extent in z. The signal to noise ratio (SNR) is defined here as the sum volume of positive defects detected divided by the sum volume of all false positives. The detection of two copies of the defect was optimal in the white band with no false positives. Black regions above and to the right of this band yielded less than two defect signatures (false negatives). Regions in red yielded false positives and calculable SNR. This graph corresponds to Die 3, Defect “By” (Fig. 7) with the “X” marking the parameter set used in that figure and for all other dipole-illuminated data in Table 1.

Tables (1)

Tables Icon

Table 1 Defect Metrics Comparisona

Metrics