DOI QR코드

DOI QR Code

Determination of Optical Constants of Thin Films in Extreme Ultraviolet Wavelength Region by an Indirect Optical Method

  • 투고 : 2012.10.30
  • 심사 : 2013.01.22
  • 발행 : 2013.02.25

초록

In this study, we propose a simple and indirect method to determine the optical constants of Mo and ITO thin films in the extreme ultraviolet (EUV) wavelength region by using X-ray reflectometry (XRR) and Rutherford backscattering spectrometry (RBS). Mo and ITO films were deposited on silicon substrates by using an RF magnetron sputtering method. The density and the composition of the deposited films were evaluated from the XRR and RBS analysis, respectively and then the optical constants of the Mo and ITO films were determined by an indirect optical method. The results suggest that the indirect method by using the XRR and RBS analysis will be useful to search for suitable high absorbing EUVL mask material quickly.

키워드

참고문헌

  1. K. Kemp and S. Wurm, "EUV lithography," C. R. Physique 7, 875-886 (2006). https://doi.org/10.1016/j.crhy.2006.10.002
  2. H. L. Chen, H. C. Cheng, T. S. Ko, F. H. Ko, and T. C. Chu, "High reflectance of reflective-type attenuated-phaseshifting masks for extreme ultraviolet lithography with high inspection contrast in deep ultraviolet regimes," J. Vac. Sci. Technol. B 22, 3049-3051 (2004). https://doi.org/10.1116/1.1813450
  3. International Technology Roadmap for Semiconductors (2010), (http://www.itrs.net).
  4. D. L. Windt, W. C. Cash Jr., M. Scott, P. Arendt, B. Newnam, R. F. Fisher, and A. B. Swartzlander, "Optical constants for thin films of Ti, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Ir, Os, Pt, and Au from 24 A to 1216 A," Appl. Opt. 27, 246-278 (1998).
  5. R. Soufli and E. M. Gullikson, "Reflectance measurements on clean surfaces for the determination of optical constants of silicon in the extreme ultraviolet-soft-x-ray region," Appl. Opt. 36, 5499-5507 (1997). https://doi.org/10.1364/AO.36.005499
  6. M. F. Perea, J. I. Larruquert, J. A. Aznarez, J. A. Mendez, M. V. Dasilva, E. Gullikson, A. Aquila, R. Soufli, and J. L. G. Fierro, "Optical constants of electron-beam evaporated boron films in the 6.8-900 eV photon energy range," J. Opt. Soc. Am. A 24, 3800-3807 (2007). https://doi.org/10.1364/JOSAA.24.003800
  7. B. L. Henke, E. M. Gullikson, and J. C. Davis, "X-ray interactions: photoabsorption, scattering, transmission, and reflection at E=50-30,000 eV, Z=1-92," Atomic Data and Nuclear Data Tables 54, 181-342 (1993), http://www-cxro.lbl.gov/. https://doi.org/10.1006/adnd.1993.1013
  8. D. Attwood, Soft X-rays and Extreme Ultraviolet Radiation (Cambridge University Press, Cambridge, UK, 1999).
  9. E. Spiller, Soft X-rays Optics (SPIE Optical Engineering Press, Bellingham, WA, USA, 1994).
  10. B. Wu and A. Kumar, Extreme Ultraviolet Lithography (McGraw-Hill, New York, USA, 2009).
  11. Y. J. Park, K. M. A. Sobahan, J. J. Kim, and C. K. Hwangbo, "Optical and structural properties of bilayer circular filter prepared by using oblique angle deposition," J. Opt. Soc. Korea 13, 218-222 (2009). https://doi.org/10.3807/JOSK.2009.13.2.218
  12. D. M. Solina, R. W. Cheary, P. D. Swift, S. Dligatch, G. M. McCredie, B. Gong, and P. Lynch, "Investigation of the interfacial structure of ultra-thin platinum films using x-ray reflectivity and x-ray photoelectron spectroscopy," Thin Solid Films 372, 94-103 (2000). https://doi.org/10.1016/S0040-6090(00)01044-0
  13. V. Holy, U. Pietsch, and T. Baumbach, High Resolution X-ray Scattering from Thin Films and Multilayers (Springer, New York, USA, 1999).
  14. P. Bergese, E. Bontempi, and L. E. Depero, "A simple solution to systematic errors in density determination by x-ray reflectivity: the XRR-density evaluation (XRR-DE) method," Appl. Surf. Sci. 253, 28-32 (2006). https://doi.org/10.1016/j.apsusc.2006.05.067
  15. L. G. Parrat, "Surface studies of solids by total reflection of x-rays," Phys. Rev. 95, 359-369 (1954). https://doi.org/10.1103/PhysRev.95.359
  16. E. Nolot and A. André, "Systematic combination of x-ray reflectometry and spectroscopic ellipsometry: a powerful technique for reliable in-lab metrology," Thin Solid Films 519, 2782-2786 (2011). https://doi.org/10.1016/j.tsf.2010.12.075
  17. O. Filies, O. Boling, K. Grewer, J. Lekki, M. Lekka, Z. Stachura, and B. Cleff, "Surface roughness of thin layers-a comparison of XRR and SFM measurements," Appl. Surf. Sci. 141, 357-365 (1999). https://doi.org/10.1016/S0169-4332(98)00524-8
  18. C. I. Muntele, I. Muntele, A. Elsamadicy, and D. Ila, "Characterization of $W_{l}C_{x}$ electrical contacts on silicon carbide using RBS and AFM/SEM," Nucl. Instr. and Meth. in Phys. Res. B 261, 561-565 (2007). https://doi.org/10.1016/j.nimb.2007.04.189
  19. L. R. Doolittle and M. O. Thompson, RUMP, Computer Graphics Service (2002).
  20. W.-K. Chu, J. M. Mayer, and M. A. Nicolet, Backscattering Spectrometry (Academic Press, New York, USA, 1978).

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