Abstract

A rapid and convenient method has been developed to facilitate the alignment of the image-plane components of point-diffraction interferometers, including the phase-shifting point-diffraction interferometer. In real time, the Fourier transform of the detected image is used to calculate a pseudoimage of the electric field in the image plane of the test optic where the critical alignment of various optical components is performed. Reconstruction of the pseudoimage is similar to off-axis, Fourier transform holography. Intermediate steps in the alignment procedure are described. Fine alignment is aided by the introduction and optimization of a global-contrast parameter that is easily calculated from the Fourier transform. Additional applications include the alignment of image-plane apertures in general optical systems, the rapid identification of patterned image-plane alignment marks, and the probing of important image-plane field properties.

© 2002 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. W. P. Linnik, “A simple interferometer for the investigation of optical systems,” Comptes Radnus de l’Académie des Sciences d’U.R.SS. 1, 208 (1933).
  2. R. N. Smartt, W. H. Steel, “Theory and application of point-diffraction interferometers (telescope testing),” Jpn. J. Appl. Phys. 14 (Suppl.14-1), 351–356 (1975).
  3. R. J. Speer, M. Chrisp, D. Turner, S. Mrowka, K. Tregidgo, “Grazing incidence interferometry: the use of the Linnik interferometer for testing image-forming reflection systems,” Appl. Opt. 18, 2003–2012 (1979).
    [CrossRef] [PubMed]
  4. G. E. Sommargren, “Diffraction methods raise interferometer accuracy,” Laser Focus World 32, 61–71 (1996).
  5. H. J. Jeong, D. A. Markle, “Point diffraction interferometer and pin mirror for use therewith,” U.S. patent5,822,066 (13October1998).
  6. O. Y. Kwon, “Multichannel phase-shifted interferometer,” Opt. Lett. 9, 59–61 (1984).
    [CrossRef] [PubMed]
  7. C. R. Mercer, K. Creath, “Liquid-crystal point-diffraction interferometer,” Opt. Lett. 19, 916–918 (1994).
    [CrossRef] [PubMed]
  8. H. Medecki, E. Tejnil, K. A. Goldberg, J. Bokor, “Phase-shifting point diffraction interferometer,” Opt. Lett. 21, 1526–1528 (1996).
    [CrossRef] [PubMed]
  9. P. P. Naulleau, K. A. Goldberg, S. H. Lee, C. Chang, D. Attwood, J. Bokor, “Extreme-ultraviolet phase-shifting point-diffraction interferometer: a wave-front metrology tool with subangstrom reference-wave accuracy,” Appl. Opt. 38, 7252–7263 (1999).
    [CrossRef]
  10. E. Tejnil, K. A. Goldberg, S. H. Lee, H. Medecki, P. J. Batson, P. E. Denham, A. A. MacDowell, J. Bokor, D. T. Attwood, “At-wavelength interferometry for EUV lithography,” J. Vac. Sci. Technol. B 15, 2455–2461 (1997).
    [CrossRef]
  11. K. A. Goldberg, P. Naulleau, P. Batson, P. Denham, H. Chapman, J. Bokor, “Extreme ultraviolet alignment and testing of a four mirror aspheric extreme ultraviolet optical system,” J. Vac. Sci. Technol. B 18, 2911–2915 (2000).
    [CrossRef]
  12. D. M. Williamson, “The elusive diffraction limit,” in Extreme Ultraviolet Lithography, Vol. 23 of OSA Proceedings Series, D. T. Attwood, F. Zernike, eds. (Optical Society of America, Washington, D.C., 1994), pp. 68–76.
  13. P. Naulleau, K. A. Goldberg, S. Lee, C. Chang, C. Bresloff, P. Batson, D. Attwood, J. Bokor, “Characterization of the accuracy of EUV phase-shifting point diffraction interferometry,” in Emerging Lithographic Technologies II, Y. Vladimirski, ed., Proc. SPIE3331, 114–123 (1998).
    [CrossRef]
  14. P. P. Naulleau, K. A. Goldberg, “A dual-domain point diffraction interferometer,” Appl. Opt. 38, 3523–3533 (1999).
    [CrossRef]
  15. K. A. Goldberg, P. P. Naulleau, “In situ alignment system for phase-shifting point-diffraction interferometry,” U.S. patent6,118,535 (12September2000).
  16. J. W. Goodman, Introduction to Fourier Optics, 2nd ed. (McGraw-Hill, New York, 1988).
  17. E. N. Leith, J. Upatnieks, “Reconstructed wavefronts and communication theory,” J. Opt. Soc. Am. 52, 1123–1130 (1962).
    [CrossRef]
  18. K. A. Goldberg, P. Naulleau, P. J. Batson, P. Denham, E. H. Anderson, J. Bokor, H. N. Chapman, “EUV interferometry of a four-mirror ring-field EUV optical system,” in Emerging Lithographic Technologies, E. A. Dobisz, ed., Proc. SPIE3997, 867–873 (2000).
  19. P. Naulleau, K. Goldberg, E. Gullikson, J. Bokor, “At-wavelength, system-level flare characterization of EUV optical systems,” Appl. Opt. 39, 2941–2947 (2000).
    [CrossRef]
  20. K. A. Goldberg, “EUV Interferometry,” Ph.D. dissertation (University of California, Berkeley, 1997).

2000

K. A. Goldberg, P. Naulleau, P. Batson, P. Denham, H. Chapman, J. Bokor, “Extreme ultraviolet alignment and testing of a four mirror aspheric extreme ultraviolet optical system,” J. Vac. Sci. Technol. B 18, 2911–2915 (2000).
[CrossRef]

P. Naulleau, K. Goldberg, E. Gullikson, J. Bokor, “At-wavelength, system-level flare characterization of EUV optical systems,” Appl. Opt. 39, 2941–2947 (2000).
[CrossRef]

1999

1997

E. Tejnil, K. A. Goldberg, S. H. Lee, H. Medecki, P. J. Batson, P. E. Denham, A. A. MacDowell, J. Bokor, D. T. Attwood, “At-wavelength interferometry for EUV lithography,” J. Vac. Sci. Technol. B 15, 2455–2461 (1997).
[CrossRef]

1996

G. E. Sommargren, “Diffraction methods raise interferometer accuracy,” Laser Focus World 32, 61–71 (1996).

H. Medecki, E. Tejnil, K. A. Goldberg, J. Bokor, “Phase-shifting point diffraction interferometer,” Opt. Lett. 21, 1526–1528 (1996).
[CrossRef] [PubMed]

1994

1984

1979

1975

R. N. Smartt, W. H. Steel, “Theory and application of point-diffraction interferometers (telescope testing),” Jpn. J. Appl. Phys. 14 (Suppl.14-1), 351–356 (1975).

1962

1933

W. P. Linnik, “A simple interferometer for the investigation of optical systems,” Comptes Radnus de l’Académie des Sciences d’U.R.SS. 1, 208 (1933).

Anderson, E. H.

K. A. Goldberg, P. Naulleau, P. J. Batson, P. Denham, E. H. Anderson, J. Bokor, H. N. Chapman, “EUV interferometry of a four-mirror ring-field EUV optical system,” in Emerging Lithographic Technologies, E. A. Dobisz, ed., Proc. SPIE3997, 867–873 (2000).

Attwood, D.

P. P. Naulleau, K. A. Goldberg, S. H. Lee, C. Chang, D. Attwood, J. Bokor, “Extreme-ultraviolet phase-shifting point-diffraction interferometer: a wave-front metrology tool with subangstrom reference-wave accuracy,” Appl. Opt. 38, 7252–7263 (1999).
[CrossRef]

P. Naulleau, K. A. Goldberg, S. Lee, C. Chang, C. Bresloff, P. Batson, D. Attwood, J. Bokor, “Characterization of the accuracy of EUV phase-shifting point diffraction interferometry,” in Emerging Lithographic Technologies II, Y. Vladimirski, ed., Proc. SPIE3331, 114–123 (1998).
[CrossRef]

Attwood, D. T.

E. Tejnil, K. A. Goldberg, S. H. Lee, H. Medecki, P. J. Batson, P. E. Denham, A. A. MacDowell, J. Bokor, D. T. Attwood, “At-wavelength interferometry for EUV lithography,” J. Vac. Sci. Technol. B 15, 2455–2461 (1997).
[CrossRef]

Batson, P.

K. A. Goldberg, P. Naulleau, P. Batson, P. Denham, H. Chapman, J. Bokor, “Extreme ultraviolet alignment and testing of a four mirror aspheric extreme ultraviolet optical system,” J. Vac. Sci. Technol. B 18, 2911–2915 (2000).
[CrossRef]

P. Naulleau, K. A. Goldberg, S. Lee, C. Chang, C. Bresloff, P. Batson, D. Attwood, J. Bokor, “Characterization of the accuracy of EUV phase-shifting point diffraction interferometry,” in Emerging Lithographic Technologies II, Y. Vladimirski, ed., Proc. SPIE3331, 114–123 (1998).
[CrossRef]

Batson, P. J.

E. Tejnil, K. A. Goldberg, S. H. Lee, H. Medecki, P. J. Batson, P. E. Denham, A. A. MacDowell, J. Bokor, D. T. Attwood, “At-wavelength interferometry for EUV lithography,” J. Vac. Sci. Technol. B 15, 2455–2461 (1997).
[CrossRef]

K. A. Goldberg, P. Naulleau, P. J. Batson, P. Denham, E. H. Anderson, J. Bokor, H. N. Chapman, “EUV interferometry of a four-mirror ring-field EUV optical system,” in Emerging Lithographic Technologies, E. A. Dobisz, ed., Proc. SPIE3997, 867–873 (2000).

Bokor, J.

P. Naulleau, K. Goldberg, E. Gullikson, J. Bokor, “At-wavelength, system-level flare characterization of EUV optical systems,” Appl. Opt. 39, 2941–2947 (2000).
[CrossRef]

K. A. Goldberg, P. Naulleau, P. Batson, P. Denham, H. Chapman, J. Bokor, “Extreme ultraviolet alignment and testing of a four mirror aspheric extreme ultraviolet optical system,” J. Vac. Sci. Technol. B 18, 2911–2915 (2000).
[CrossRef]

P. P. Naulleau, K. A. Goldberg, S. H. Lee, C. Chang, D. Attwood, J. Bokor, “Extreme-ultraviolet phase-shifting point-diffraction interferometer: a wave-front metrology tool with subangstrom reference-wave accuracy,” Appl. Opt. 38, 7252–7263 (1999).
[CrossRef]

E. Tejnil, K. A. Goldberg, S. H. Lee, H. Medecki, P. J. Batson, P. E. Denham, A. A. MacDowell, J. Bokor, D. T. Attwood, “At-wavelength interferometry for EUV lithography,” J. Vac. Sci. Technol. B 15, 2455–2461 (1997).
[CrossRef]

H. Medecki, E. Tejnil, K. A. Goldberg, J. Bokor, “Phase-shifting point diffraction interferometer,” Opt. Lett. 21, 1526–1528 (1996).
[CrossRef] [PubMed]

P. Naulleau, K. A. Goldberg, S. Lee, C. Chang, C. Bresloff, P. Batson, D. Attwood, J. Bokor, “Characterization of the accuracy of EUV phase-shifting point diffraction interferometry,” in Emerging Lithographic Technologies II, Y. Vladimirski, ed., Proc. SPIE3331, 114–123 (1998).
[CrossRef]

K. A. Goldberg, P. Naulleau, P. J. Batson, P. Denham, E. H. Anderson, J. Bokor, H. N. Chapman, “EUV interferometry of a four-mirror ring-field EUV optical system,” in Emerging Lithographic Technologies, E. A. Dobisz, ed., Proc. SPIE3997, 867–873 (2000).

Bresloff, C.

P. Naulleau, K. A. Goldberg, S. Lee, C. Chang, C. Bresloff, P. Batson, D. Attwood, J. Bokor, “Characterization of the accuracy of EUV phase-shifting point diffraction interferometry,” in Emerging Lithographic Technologies II, Y. Vladimirski, ed., Proc. SPIE3331, 114–123 (1998).
[CrossRef]

Chang, C.

P. P. Naulleau, K. A. Goldberg, S. H. Lee, C. Chang, D. Attwood, J. Bokor, “Extreme-ultraviolet phase-shifting point-diffraction interferometer: a wave-front metrology tool with subangstrom reference-wave accuracy,” Appl. Opt. 38, 7252–7263 (1999).
[CrossRef]

P. Naulleau, K. A. Goldberg, S. Lee, C. Chang, C. Bresloff, P. Batson, D. Attwood, J. Bokor, “Characterization of the accuracy of EUV phase-shifting point diffraction interferometry,” in Emerging Lithographic Technologies II, Y. Vladimirski, ed., Proc. SPIE3331, 114–123 (1998).
[CrossRef]

Chapman, H.

K. A. Goldberg, P. Naulleau, P. Batson, P. Denham, H. Chapman, J. Bokor, “Extreme ultraviolet alignment and testing of a four mirror aspheric extreme ultraviolet optical system,” J. Vac. Sci. Technol. B 18, 2911–2915 (2000).
[CrossRef]

Chapman, H. N.

K. A. Goldberg, P. Naulleau, P. J. Batson, P. Denham, E. H. Anderson, J. Bokor, H. N. Chapman, “EUV interferometry of a four-mirror ring-field EUV optical system,” in Emerging Lithographic Technologies, E. A. Dobisz, ed., Proc. SPIE3997, 867–873 (2000).

Chrisp, M.

Creath, K.

Denham, P.

K. A. Goldberg, P. Naulleau, P. Batson, P. Denham, H. Chapman, J. Bokor, “Extreme ultraviolet alignment and testing of a four mirror aspheric extreme ultraviolet optical system,” J. Vac. Sci. Technol. B 18, 2911–2915 (2000).
[CrossRef]

K. A. Goldberg, P. Naulleau, P. J. Batson, P. Denham, E. H. Anderson, J. Bokor, H. N. Chapman, “EUV interferometry of a four-mirror ring-field EUV optical system,” in Emerging Lithographic Technologies, E. A. Dobisz, ed., Proc. SPIE3997, 867–873 (2000).

Denham, P. E.

E. Tejnil, K. A. Goldberg, S. H. Lee, H. Medecki, P. J. Batson, P. E. Denham, A. A. MacDowell, J. Bokor, D. T. Attwood, “At-wavelength interferometry for EUV lithography,” J. Vac. Sci. Technol. B 15, 2455–2461 (1997).
[CrossRef]

Goldberg, K.

Goldberg, K. A.

K. A. Goldberg, P. Naulleau, P. Batson, P. Denham, H. Chapman, J. Bokor, “Extreme ultraviolet alignment and testing of a four mirror aspheric extreme ultraviolet optical system,” J. Vac. Sci. Technol. B 18, 2911–2915 (2000).
[CrossRef]

P. P. Naulleau, K. A. Goldberg, S. H. Lee, C. Chang, D. Attwood, J. Bokor, “Extreme-ultraviolet phase-shifting point-diffraction interferometer: a wave-front metrology tool with subangstrom reference-wave accuracy,” Appl. Opt. 38, 7252–7263 (1999).
[CrossRef]

P. P. Naulleau, K. A. Goldberg, “A dual-domain point diffraction interferometer,” Appl. Opt. 38, 3523–3533 (1999).
[CrossRef]

E. Tejnil, K. A. Goldberg, S. H. Lee, H. Medecki, P. J. Batson, P. E. Denham, A. A. MacDowell, J. Bokor, D. T. Attwood, “At-wavelength interferometry for EUV lithography,” J. Vac. Sci. Technol. B 15, 2455–2461 (1997).
[CrossRef]

H. Medecki, E. Tejnil, K. A. Goldberg, J. Bokor, “Phase-shifting point diffraction interferometer,” Opt. Lett. 21, 1526–1528 (1996).
[CrossRef] [PubMed]

K. A. Goldberg, P. P. Naulleau, “In situ alignment system for phase-shifting point-diffraction interferometry,” U.S. patent6,118,535 (12September2000).

K. A. Goldberg, P. Naulleau, P. J. Batson, P. Denham, E. H. Anderson, J. Bokor, H. N. Chapman, “EUV interferometry of a four-mirror ring-field EUV optical system,” in Emerging Lithographic Technologies, E. A. Dobisz, ed., Proc. SPIE3997, 867–873 (2000).

P. Naulleau, K. A. Goldberg, S. Lee, C. Chang, C. Bresloff, P. Batson, D. Attwood, J. Bokor, “Characterization of the accuracy of EUV phase-shifting point diffraction interferometry,” in Emerging Lithographic Technologies II, Y. Vladimirski, ed., Proc. SPIE3331, 114–123 (1998).
[CrossRef]

K. A. Goldberg, “EUV Interferometry,” Ph.D. dissertation (University of California, Berkeley, 1997).

Goodman, J. W.

J. W. Goodman, Introduction to Fourier Optics, 2nd ed. (McGraw-Hill, New York, 1988).

Gullikson, E.

Jeong, H. J.

H. J. Jeong, D. A. Markle, “Point diffraction interferometer and pin mirror for use therewith,” U.S. patent5,822,066 (13October1998).

Kwon, O. Y.

Lee, S.

P. Naulleau, K. A. Goldberg, S. Lee, C. Chang, C. Bresloff, P. Batson, D. Attwood, J. Bokor, “Characterization of the accuracy of EUV phase-shifting point diffraction interferometry,” in Emerging Lithographic Technologies II, Y. Vladimirski, ed., Proc. SPIE3331, 114–123 (1998).
[CrossRef]

Lee, S. H.

P. P. Naulleau, K. A. Goldberg, S. H. Lee, C. Chang, D. Attwood, J. Bokor, “Extreme-ultraviolet phase-shifting point-diffraction interferometer: a wave-front metrology tool with subangstrom reference-wave accuracy,” Appl. Opt. 38, 7252–7263 (1999).
[CrossRef]

E. Tejnil, K. A. Goldberg, S. H. Lee, H. Medecki, P. J. Batson, P. E. Denham, A. A. MacDowell, J. Bokor, D. T. Attwood, “At-wavelength interferometry for EUV lithography,” J. Vac. Sci. Technol. B 15, 2455–2461 (1997).
[CrossRef]

Leith, E. N.

Linnik, W. P.

W. P. Linnik, “A simple interferometer for the investigation of optical systems,” Comptes Radnus de l’Académie des Sciences d’U.R.SS. 1, 208 (1933).

MacDowell, A. A.

E. Tejnil, K. A. Goldberg, S. H. Lee, H. Medecki, P. J. Batson, P. E. Denham, A. A. MacDowell, J. Bokor, D. T. Attwood, “At-wavelength interferometry for EUV lithography,” J. Vac. Sci. Technol. B 15, 2455–2461 (1997).
[CrossRef]

Markle, D. A.

H. J. Jeong, D. A. Markle, “Point diffraction interferometer and pin mirror for use therewith,” U.S. patent5,822,066 (13October1998).

Medecki, H.

E. Tejnil, K. A. Goldberg, S. H. Lee, H. Medecki, P. J. Batson, P. E. Denham, A. A. MacDowell, J. Bokor, D. T. Attwood, “At-wavelength interferometry for EUV lithography,” J. Vac. Sci. Technol. B 15, 2455–2461 (1997).
[CrossRef]

H. Medecki, E. Tejnil, K. A. Goldberg, J. Bokor, “Phase-shifting point diffraction interferometer,” Opt. Lett. 21, 1526–1528 (1996).
[CrossRef] [PubMed]

Mercer, C. R.

Mrowka, S.

Naulleau, P.

K. A. Goldberg, P. Naulleau, P. Batson, P. Denham, H. Chapman, J. Bokor, “Extreme ultraviolet alignment and testing of a four mirror aspheric extreme ultraviolet optical system,” J. Vac. Sci. Technol. B 18, 2911–2915 (2000).
[CrossRef]

P. Naulleau, K. Goldberg, E. Gullikson, J. Bokor, “At-wavelength, system-level flare characterization of EUV optical systems,” Appl. Opt. 39, 2941–2947 (2000).
[CrossRef]

K. A. Goldberg, P. Naulleau, P. J. Batson, P. Denham, E. H. Anderson, J. Bokor, H. N. Chapman, “EUV interferometry of a four-mirror ring-field EUV optical system,” in Emerging Lithographic Technologies, E. A. Dobisz, ed., Proc. SPIE3997, 867–873 (2000).

P. Naulleau, K. A. Goldberg, S. Lee, C. Chang, C. Bresloff, P. Batson, D. Attwood, J. Bokor, “Characterization of the accuracy of EUV phase-shifting point diffraction interferometry,” in Emerging Lithographic Technologies II, Y. Vladimirski, ed., Proc. SPIE3331, 114–123 (1998).
[CrossRef]

Naulleau, P. P.

Smartt, R. N.

R. N. Smartt, W. H. Steel, “Theory and application of point-diffraction interferometers (telescope testing),” Jpn. J. Appl. Phys. 14 (Suppl.14-1), 351–356 (1975).

Sommargren, G. E.

G. E. Sommargren, “Diffraction methods raise interferometer accuracy,” Laser Focus World 32, 61–71 (1996).

Speer, R. J.

Steel, W. H.

R. N. Smartt, W. H. Steel, “Theory and application of point-diffraction interferometers (telescope testing),” Jpn. J. Appl. Phys. 14 (Suppl.14-1), 351–356 (1975).

Tejnil, E.

E. Tejnil, K. A. Goldberg, S. H. Lee, H. Medecki, P. J. Batson, P. E. Denham, A. A. MacDowell, J. Bokor, D. T. Attwood, “At-wavelength interferometry for EUV lithography,” J. Vac. Sci. Technol. B 15, 2455–2461 (1997).
[CrossRef]

H. Medecki, E. Tejnil, K. A. Goldberg, J. Bokor, “Phase-shifting point diffraction interferometer,” Opt. Lett. 21, 1526–1528 (1996).
[CrossRef] [PubMed]

Tregidgo, K.

Turner, D.

Upatnieks, J.

Williamson, D. M.

D. M. Williamson, “The elusive diffraction limit,” in Extreme Ultraviolet Lithography, Vol. 23 of OSA Proceedings Series, D. T. Attwood, F. Zernike, eds. (Optical Society of America, Washington, D.C., 1994), pp. 68–76.

Appl. Opt.

Comptes Radnus de l’Académie des Sciences d’U.R.SS.

W. P. Linnik, “A simple interferometer for the investigation of optical systems,” Comptes Radnus de l’Académie des Sciences d’U.R.SS. 1, 208 (1933).

J. Opt. Soc. Am.

J. Vac. Sci. Technol. B

E. Tejnil, K. A. Goldberg, S. H. Lee, H. Medecki, P. J. Batson, P. E. Denham, A. A. MacDowell, J. Bokor, D. T. Attwood, “At-wavelength interferometry for EUV lithography,” J. Vac. Sci. Technol. B 15, 2455–2461 (1997).
[CrossRef]

K. A. Goldberg, P. Naulleau, P. Batson, P. Denham, H. Chapman, J. Bokor, “Extreme ultraviolet alignment and testing of a four mirror aspheric extreme ultraviolet optical system,” J. Vac. Sci. Technol. B 18, 2911–2915 (2000).
[CrossRef]

Jpn. J. Appl. Phys.

R. N. Smartt, W. H. Steel, “Theory and application of point-diffraction interferometers (telescope testing),” Jpn. J. Appl. Phys. 14 (Suppl.14-1), 351–356 (1975).

Laser Focus World

G. E. Sommargren, “Diffraction methods raise interferometer accuracy,” Laser Focus World 32, 61–71 (1996).

Opt. Lett.

Other

K. A. Goldberg, P. P. Naulleau, “In situ alignment system for phase-shifting point-diffraction interferometry,” U.S. patent6,118,535 (12September2000).

J. W. Goodman, Introduction to Fourier Optics, 2nd ed. (McGraw-Hill, New York, 1988).

K. A. Goldberg, P. Naulleau, P. J. Batson, P. Denham, E. H. Anderson, J. Bokor, H. N. Chapman, “EUV interferometry of a four-mirror ring-field EUV optical system,” in Emerging Lithographic Technologies, E. A. Dobisz, ed., Proc. SPIE3997, 867–873 (2000).

K. A. Goldberg, “EUV Interferometry,” Ph.D. dissertation (University of California, Berkeley, 1997).

H. J. Jeong, D. A. Markle, “Point diffraction interferometer and pin mirror for use therewith,” U.S. patent5,822,066 (13October1998).

D. M. Williamson, “The elusive diffraction limit,” in Extreme Ultraviolet Lithography, Vol. 23 of OSA Proceedings Series, D. T. Attwood, F. Zernike, eds. (Optical Society of America, Washington, D.C., 1994), pp. 68–76.

P. Naulleau, K. A. Goldberg, S. Lee, C. Chang, C. Bresloff, P. Batson, D. Attwood, J. Bokor, “Characterization of the accuracy of EUV phase-shifting point diffraction interferometry,” in Emerging Lithographic Technologies II, Y. Vladimirski, ed., Proc. SPIE3331, 114–123 (1998).
[CrossRef]

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (3)

Fig. 1
Fig. 1

Schematic representation of the PS/PDI. Pinhole diffraction in the object and the image planes produces spherical reference waves. A grating beam splitter creates multiple copies of the test beam, focused in the image plane. A mask containing a window and a very small pinhole transmits one test beam and spatially filters another to become the reference beam.

Fig. 2
Fig. 2

PS/PDI mask (a) contains a large window for the transmission of the test beam and at least one small pinhole (shown at center)—black areas are transmissive, white are opaque. Features on the nominally square window aid in alignment. For several different configurations, (b)–(g) are simulations of the logarithmically scaled Fourier transform of the detected intensity, shown on inverted grayscale. (b) Test beam only, with the beam passing though the center of the window. (c)–(f) Intermediate steps in the alignment of the PS/PDI with the test beam passing through the window and the reference beam being aligned to pass through the pinhole. Optimal alignment is achieved (f) when the window is most clearly visible. (g) A single beam passes through the pinhole, with low-level, scattered light passing through the window.

Fig. 3
Fig. 3

Logarithmically scaled FFTs of experimental measurements of alignment marks demonstrate how these marks are read in situ. In (a) and (b), the single beam passes through the stenciled symbols in the image plane and is recorded in the far field by a detector. The Fourier transform of the recorded images is equivalent to the autocorrelation of the image-plane field and thus reveals the row and the column markers with a polar-symmetric reflected copy. The open areas are 1 µm wide. (c) and (d) Fourier transforms of interferograms recorded during PS/PDI measurement. A 3-bit binary code is patterned into the window edges to indicate the row and the column numbers within an array of similar marks. The windows are 3 µm wide; the alignment marks protrude by 1/3 µm from the square.

Equations (11)

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

|Ar|2=ArA*raρ * a*-ρ.
aρ=δρ+cmρ-ρ0,
aρ=δρ+cmρ-ρ0;
|Ar|2=δρ+cmρ-ρ0 * δ*-ρ+cm*ρ0-ρ =δρ+cmρ-ρ0+cm*ρ0-ρ+c2mρ * m*-ρ.
aρ=j bjδρ-js+cmρ-ρ0.
aρ=δρ+dδρ-s+cmρ-ρ0=δρ+dδρ-s+cmρ-ρ0.
|Ar|2=δρ+dδρ-s+dδ*s-ρ+cmρ-ρ0+cm*ρ0-ρ+cdmρ-ρ0-s+cdm*ρ0+s-ρ+c2mρ * m*-ρ.
aρ=dδρ+cmρ-s=dδρ+cmρ-s.
|Aρ|2=d2δρ+dcmρ-s+dcm*s-ρ+c2mρ * m*-ρ.
λμm4NAnNAndμm/cycle.
NM4/c2.

Metrics