Microsystem Technologies

, Volume 13, Issue 3–4, pp 355–360 | Cite as

Process conditions in X-ray lithography for the fabrication of devices with sub-micron feature sizes

Technical Paper

Abstract

This article describes the fabrication of polymer structures with lateral dimensions in the sub-micron regime using hard X-rays (λc ≈ 0.4 nm) from the electron storage ring ANKA. Spincoated polymethylmethacrylate (PMMA) grades have been analyzed with respect to development rates and contrast. The contrast has been determined to be constant over a wide dose regime but rapidly decreases for dose values below 1 kJ/cm3. Films with a thickness from 2 to 11 μm have been patterned using a high resolution X-ray mask consisting of 2 μm thick gold absorbers on a suspended 1 μm thick silicon nitride membrane. The fabrication of sub-micron X-ray lithography structures with feature sizes down to 400 nm is confined by the mechanical parameters of the resist material and the process conditions. Surface tension after development limits the achievable aspect ratio of isolated pillars and walls, depending on the actual resist height. PMMA structures have been successfully used as template for electroplating of 1 μm thick gold to demonstrate the fabrication capability of sub-micron scale metal parts.

References

  1. Achenbach S, Mohr J, Pantenburg FJ (2000) Application of Scanning Probe Microscopy for the determination of the structural accuracy of high aspect ratio microstructures. Microelectron Eng 53:637–640CrossRefGoogle Scholar
  2. Achenbach S (2004) Deep sub micron high aspect ratio polymer structures produced by deep X-ray lithography. Microsyst Technol 10(6–7):493–497CrossRefGoogle Scholar
  3. Achenbach S, Mappes T, Fettig R, Kando J, Mohr J (2004a) Process conditions for the fabrication of sub-wavelength scale structures by X-ray lithography in PMMA films. Proc SPIE 5450:86–94Google Scholar
  4. Achenbach S, Mappes T, Mohr J (2004b) Structure quality of high aspect ratio sub micron polymer structures patterned at the electron storage ring ANKA. J Vac Sci Tech B 22(6):3196–3201CrossRefGoogle Scholar
  5. Becker EW, Ehrfeld W, Hagmann P, Maner A, Münchmeyer D (1986) Fabrication of microstructures with high aspect ratios and great structural heights by synchrotron radiation lithography, galvanoforming and plastic moulding (LIGA process). Microelectron Eng 4:36CrossRefGoogle Scholar
  6. Cuisin C et al (1999) Fabrication of three-dimensional microstructures by high resolution X-ray lithography. J Vac Sci Technol B 17:3444–3448CrossRefGoogle Scholar
  7. Deguchi K, Miyoshi K et al (1992) Application of X-ray lithography with a single layer resist process to subquartermicron large scale integrated circuit fabrication. J Vac Sci Technol B 10:3145–3149CrossRefGoogle Scholar
  8. Di Fabricio E, Fillipo R, Cabrini S, Kumar R, Perennes F et al (2004) X-ray lithography for micro & nano fabrication at ELETTRA for interdisciplinary applications. J Phys Condens Matter 16:3517–3535CrossRefGoogle Scholar
  9. Fettig R, Hein H, Schulz J (2003) High aspect ratio hole array filters for a wide range of wavelength. In: international workshop on thermal detectors for space-based applications (TDW2003), Washington, USAGoogle Scholar
  10. Ghica V, Glashauser W (1982) Verfahren für die spannungsrißfrei Entwicklung von bestrahlten Polymethylmethacrylat-Schichten. German Patent No. 3 039 110Google Scholar
  11. John S (1987) Strong localization of photons in certain distorted dielectric superlattices. Phys Rev Lett 58:2486–2489CrossRefGoogle Scholar
  12. Liguda C, Böttger G, Eich M et al (2001) Polymer photonic crystal slab waveguides. Appl Phys Lett 78:2434–2436CrossRefGoogle Scholar
  13. Pantenburg FJ, Achenbach S, Mohr J (1998a) Characterisation of defects in very high deep-etch X-ray lithography microstructures. Microsystem Tech 4(2):89–94CrossRefGoogle Scholar
  14. Pantenburg FJ, Achenbach S, Mohr J (1998b) Influence of developer temperature and resist material on the structure quality in deep X-ray lithography. J Vac Sci Technol B 16:3547–3551CrossRefGoogle Scholar
  15. Reynolds G, Taylor J (1999) Direct measurement of X-ray mask sidewall roughness and its contribution on the overall sidewall roughness of chemically amplified resist features. J Vac Sci Technol B 17:3420–3425CrossRefGoogle Scholar
  16. Schomburg W, Bley P, Hein H, Mohr J (1990) Masken für die Röntgentiefenlithographie. VDI Berichte 870:133–154Google Scholar
  17. Vladimirsky O, Leonard Q et al (1999) Sub-100nm imaging in X-ray lithography. Proc SPIE 3676:478–484Google Scholar
  18. Weibel GL, Ober CK (2002) An overview of supercritical CO2 applications in microelectronics processing. Microelectron Eng 65:145–152CrossRefGoogle Scholar
  19. White V, Cerrina F (1992) Metal-less X-ray phase shift masks for nanolithography. J Vac Sci Technol B 10:3141–3144CrossRefGoogle Scholar
  20. Yablonovitch E (1987) Inhibited spontaneous emission in solid-state physics and electronics. Phys Rev Lett 58:2059–2062CrossRefGoogle Scholar
  21. Yang L, Khan M, Taylor JW, Vladimirsky Y, Dandekar NV (2000) A processing latitude study of X-ray phase shifting masks. Proc SPIE 3997:530–538Google Scholar

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  1. 1.Forschungszentrum KarlsruheInstitut für MikrostrukturtechnikKarlsruheGermany

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