Submicron fluorescence imaging of soft x‐ray aerial images, using a high resolution fluorescent crystal is reported. Features as small as 0.1 μm were observed using a commercially available single‐crystal phosphor, STI‐F10G (Star Tech Instruments Inc. P. O. Box 2536, Danbury, CT 06813‐2536), excited with 139 Å light. Its quantum efficiency was estimated to be 5–10 times that of sodium salicylate and to be constant over a broad spectral range from 30 to 400 Å. A comparison with a terbium‐activated yttrium orthosilicate fluorescent crystal is also presented. Several applications, such as the characterization of the aerial images produced by deep ultraviolet or extreme ultraviolet lithographic exposure tools, are envisaged.

1.
J. A. R. Samson, Techniques of Vacuum Ultraviolet Spectroscopy (Wiley, New York, 1967).
2.
G. W. Berkstresser, J. Shmulovich, D. T. C. Huo, and G. Matulis, J. Electrochem. Soc. 134, 2624 (1987); G. W. Berkstresser, J. Shmulovich, D. T. C. Huo, G. Matulis, C. D. Brandle, and A. J. Valentino, J. Electrochem. Soc. 135, 1302 (1988).
3.
Y. Horikawa, K. Nagai, S. Mochimaru, and Y. Iketakai, J. Microsc. 172, 189 (1993); see also, Proceedings of the Third International Conference, London, 1990, edited by A. G. Michette, G. R. Morisson, and C. J. Buckley (Springer-Verlag, Berlin-Heidelberg, 1992).
4.
A. M. Fauchet, B. C. Craft, J. N. Galayda, H. Hsieh, A. Luccio, J. B. Murphy, C. Pellegrini, A. van Steerbergen, G. Vignola, L. H. Yu, R. R. Freeman, and B. M. Kincaid, National Synchrotron Light Source Annual Report (National Technical Information Services, Springfield, MA, 1985), p. 137.
5.
J. E. Bjorkholm, J. Bokor, L. Eichner, R. R. Freeman, J. Gregus, T. E. Jewell, W. M. Mansfield, A. A. MacDowell, E. L. Raab, W. T. Silfvast, L. H. Szeto, D. M. Tennant, W. K. Waskiewicz, D. L. White, D. L. Windt, O. R. Wood II, and J. H. Bruning, J. Vac. Sci. Technol. B 8, 1509 (1990); D. L. White, J. E. Bjorkholm, J. Bokor, L. Eichner, R. R. Freeman, T. E. Jewell, W. M. Mansfield, A. A. MacDowell, L. H. Szeto, D. W. Taylor, D. M. Tennant, W. K. Waskiewicz, D. L. Windt, and O. R. Wood II, Solid State Technol. 34, 37 (1991).
6.
G. P.
Williams,
M. R.
Howells,
N.
Lucas
, and
P. Z.
Takacs,
Nucl. Instrum. Methods
222
,
99
(
1984
).
Google Scholar
 
7.
J. A. R. Samson and G. N. Haddad, J. Opt. Soc. Am. 64, 1346 (1974); V. Kumar and A. K. Datta; Appl. Opt. 18, 1414 (1979); D. K. Bedford and M. F. St. J. Mann, J. Phys. E: Sci. Instrum. 17, 866 (1984).
8.
G.
Blasse
and
A.
Brill,
J. Chem. Phys.
47
,
5139
(
1967
).
Google Scholar
 
9.
G. W. Berkstresser, J. Shmulovich, and A. M. Wittenberg, Technical Report AT&T Bell Laboratories, AAMRL-TR-86-041 (1986).
Schematic diagram of the imaging experiment. The EUV image is formed by the Schwarzschild camera which uses multilayer coated mirrors for 140 Å light. The fluorescent image is obtained by placing a phosphor plate at the EUV image plane. It is viewed with a microscope composed of a 100× objective with a numerical aperture of 1.25 and a 5× long working distance microscope.
Excitation and emission spectra of STI-F10G (solid circles) and (Y2−xTbx)SiO5 (open circles). (a) Both phosphors show a constant quantum efficiency over a fairly broad spectral range. (b) Emission spectra showing the broad fluorescence of the STI-F10G phosphor and the characteristic features of the terbium-activated yttrium orthosilicate.
Fluorescent image and mask. (a) The mask used for the imaging experiment is composed of several patterns, which comprise isolated lines ranging from 10 to 2 μm. (b) All the lines, ranging from 0.5 to 0.1 μm after reduction, can be clearly identified on this fluorescent image.
This content is only available via PDF.
© 1995 American Institute of Physics.
1995
American Institute of Physics
You do not currently have access to this content.