1. Transmission Grating Spectrometer for EUV Lithography Nathan Gray Advisors: Alexander Shevelko, Larry Knight, and Scott Bergeson Student Group Members: Matthew Harrison, Jeff Kemp, Bryce Allred, Jershon Lopez

2. Extreme Ultraviolet (EUV) 1-1000 Å Image modified from: NASAexplores Models of the Electromagnetic Spectrum student sheet. lot.astro.utoronto.ca/spectrum.htmllot.astro.utoronto.ca/spectrum.html

3. Extreme Ultraviolet (EUV) 1-1000 Å Image modified from: NASAexplores Models of the Electromagnetic Spectrum student sheet. lot.astro.utoronto.ca/spectrum.htmllot.astro.utoronto.ca/spectrum.html Absorbed by Everything: Air

4. Extreme Ultraviolet (EUV) 1-1000 Å Image modified from: NASAexplores Models of the Electromagnetic Spectrum student sheet. lot.astro.utoronto.ca/spectrum.htmllot.astro.utoronto.ca/spectrum.html Absorbed by Everything: Air Glass

5. Extreme Ultraviolet (EUV) 1-1000 Å Image modified from: NASAexplores Models of the Electromagnetic Spectrum student sheet. lot.astro.utoronto.ca/spectrum.htmllot.astro.utoronto.ca/spectrum.html Absorbed by Everything: Air Glass Plastic

6. Extreme Ultraviolet (EUV) 1-1000 Å Image modified from: NASAexplores Models of the Electromagnetic Spectrum student sheet. lot.astro.utoronto.ca/spectrum.htmllot.astro.utoronto.ca/spectrum.html Absorbed by Everything: Air Glass Plastic Ponies

7. Extreme Ultraviolet (EUV) Absorbed by Everything: Air Glass Plastic Must operate under vacuum (our chamber is at 30-100 mtorr) Must use mirrors in place of conventional optics. This makes spectroscopy in the EUV range complicated.

8. EUV range transmission gratings:

9. Recent transmission grating development allows for EUV range gratings 200 nm period (5000 lines/mm)

10. EUV range transmission gratings: Recent transmission grating development allows for EUV range gratings 200 nm period (5000 lines/mm) Transmission grating spectrometers are superior to reflection grating spectrometers

11. Possible Configurations Entrance Slit Grating Detector Simple Transmission Grating Spectrometer

12. Possible Configurations Single Mirror Geometry Single Mirror Geometry Entrance Slit Grating Detector Spherical Mirror High spectral resolution and luminosity Mirror collects large solid angle

13. Our Configurations Double Mirror Geometry Double Mirror Geometry Grating Entrance Slit Flat Mirror Detector Spherical Mirror Designed by Dr. Alexander Shevelko

14. Knight/Shevelko Group Spectrometer Configuration

17. Electron Temperature Study Tungsten

18. Efficiency Calculation Major advantage of transmission grating over reflection grating Must take transmission through wires into account (phase shift) Materials: Au 25 nm Si4N3 200 nm Radiation

19. Formulae

20. Efficiency Calculation Fujikawa et al. Method Schopper et al. Method H. W. Schopper et al., Appl. Opt. 16, 1088 (1977). C. Fujikawa et al., Rev. Sci. Instrum. 69, 2849 (1998).

21. Absolute Calibration grating efficiency X spherical mirror reflectivity X flat mirror reflectivity = total spectrometer efficiency = total spectrometer efficiency

22. Absolute Calibration grating efficiency X spherical mirror reflectivity X flat mirror reflectivity = total spectrometer efficiency = total spectrometer efficiency total spectrometer efficiency X detector calibration = absolute calibration

23. Absolute Calibration grating efficiency X spherical mirror reflectivity X flat mirror reflectivity = total spectrometer efficiency = total spectrometer efficiency total spectrometer efficiency X detector calibration = absolute calibration absolute calibration = Intensity scaled to units of actual photon flux, instead of just relative intensity.

24. Absolute Calibration grating efficiency X spherical mirror reflectivity X flat mirror reflectivity = total spectrometer efficiency = total spectrometer efficiency total spectrometer efficiency X detector calibration = absolute calibration absolute calibration = Intensity scaled to units of actual photon flux, instead of just relative intensity. Detector calibration: completed at Lebedev Physical Institute by Oleg Yakushev

25. EUV Lithography International Technology Roadmap for Semiconductors printable patterns with 32 nm between features are required by the semiconductor industry by 2009

26. EUV Lithography Main limitation is wavelength of light source Higher Resolution requires a source with smaller wavelength

27. V. Bakshi, EUV Sources for Lithography, SPIE Press Book, 2006. V. Bakshi, EUV Sources for Lithography, SPIE Press Book, 2006. Typical EUV wafer scanner

28. EUV Lithography Typical EUV Lithography apparatus: 11 mirror multilayer Mo/Sn multilayer mirrors with reflections around 66% each. The overall transmission in the EUV scanner is less than 1%, The mirrors reflect a bandwidth of 2% around a central wavelength of 135 °A.

29. EUV Lithography Source candidates: Lithium and Tin plasmas

30. EUV Lithography Mirror heating Mirror heating Unwanted radiation Unwanted radiation Target purity Target purity Plasma parameters (electron temperatures, absolute outputs, etc.) Plasma parameters (electron temperatures, absolute outputs, etc.)

32. Current WRS Planned WRS with multiple gratings

33. Acknowledgements Dr. Shevelko Dr. Shevelko Dr. Knight Dr. Knight Matt Harrison and the other members of my group Matt Harrison and the other members of my group The chemists (especially Dr. Asplund) The chemists (especially Dr. Asplund)