Advertisement

Fabrication of metal suspending nanostructures by nanoimprint lithography (NIL) and isotropic reactive ion etching (RIE)

  • GuoYong XieEmail author
  • Jin Zhang
  • YongYi Zhang
  • YingYing Zhang
  • Tao Zhu
  • ZhongFan LiuEmail author
Article

Abstract

We report herein a rational approach for fabricating metal suspending nanostructures by nanoimprint lithography (NIL) and isotropic reactive ion etching (RIE). The approach comprises three principal steps: (1) mold fabrication, (2) structure replication by NIL, and (3) suspending nanostructures creation by isotropic RIE. Using this approach, suspending nanostructures with Au, Au/Ti or Ti/Au bilayers, and Au/Ti/Au sandwiched structures are demonstrated. For Au nanostructures, straight suspending nanostructures can be obtained when the thickness of Au film is up to 50 nm for nano-bridge and 90 nm for nano-finger patterns. When the thickness of Au is below 50 nm for nano-bridge and 90 nm for nano-finger, the Au suspending nanostructures bend upward as a result of the mismatch of thermal expansion between the thin Au films and Si substrate. This leads to residual stresses in the thin Au films. For Au/Ti or Ti/Au bilayers nanostructures, the cantilevers bend toward Au film, since Au has a larger thermal expansion coefficient than that of Ti. While in the case of sandwich structures, straight suspending nanostructures are obtained, this may be due to the balance of residual stress between the thin films.

Keywords

suspending nanostructure fabrication nanoimprint lithography (NIL) isotropic reactive ion etching (RIE) 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Brand O, Baltes H. Sensors, vol 4. New York: Wiley, 1998Google Scholar
  2. 2.
    Craighead H G. Nanoelectromechanical systems. Science, 2000, 290: 1532–1535CrossRefGoogle Scholar
  3. 3.
    Forsen E, Nilsson S G, Carlberg P, et al. Fabrication of cantilever based mass sensors integrated with CMOS using direct write laser lithography on resist. Nanotechnology, 2004, 15: S628–633CrossRefGoogle Scholar
  4. 4.
    Boisen A, Birkelund K, Hansen O, et al. Fabrication of submicron suspended structures by laser and atomic force microscopy lithography on aluminum combined with reactive ion etching. J Vac Sci Technol B, 1998, 16(6): 2977–2981CrossRefGoogle Scholar
  5. 5.
    Abadal G, Boisen A, Davis Z J, et al. Combined laser and atomic force microscope lithography on aluminum: Mask fabrication for nanoelec-tromechanical systems. Appl Phys Lett, 1999, 74(21): 3206–3208CrossRefGoogle Scholar
  6. 6.
    Davis Z J, Abadal G, Kuhn O, et al. Fabrication and characterization of nanoresonating devices for mass detection. J Vac Sci Technol B, 2000, 18(2): 612–616CrossRefGoogle Scholar
  7. 7.
    Abadal G., Davis Z J, Helbo B, et al. Electromechanical model of a resonating nano-cantilever-based sensor for high-resolution and high-sensitivity mass detection. Nanotechnology, 2001, 12: 100–104CrossRefGoogle Scholar
  8. 8.
    Ghatnekar-Nilsson S, Forsen E, Abadal G, et al. Resonators with integrated CMOS circuitry for mass sensing applications, fabricated by electron beam lithography. Nanotechnology, 2005, 16: 98–102CrossRefGoogle Scholar
  9. 9.
    Gupta A, Akin D, Bashir R. Single virus particle mass detection using microresonators with nanoscale thickness. Appl phys Lett, 2004, 84(11): 1976–1978CrossRefGoogle Scholar
  10. 10.
    Mastrangelo C H, Hsu C H. Mechanical stability and adhesion of microstructures under capillary forces. J Microelectromech Syst, 1993, 2: 33–55CrossRefGoogle Scholar
  11. 11.
    Tas N, Sonnenberg T, Jansen H, et al. Stiction in surface micromachining. J Micromech Microeng, 1996, 6: 385–397CrossRefGoogle Scholar
  12. 12.
    Bartek M, Wolffenbuttel R F. Dry release of metal structures in oxygen plasma: process characterization and optimization. J Micromech Microeng, 1998, 8: 91–94CrossRefGoogle Scholar
  13. 13.
    Forsen E, Davis Z J, Dong M, et al. Dry release of suspended nanostructures. Microelect Eng, 2004, 73–74: 487–490CrossRefGoogle Scholar
  14. 14.
    Chou S Y, Krauss P R, Renstrom P J. Imprint of sub-25 nm vias and trenches in polymer. Appl Phys Lett, 1995, 67(21): 3114–3116CrossRefGoogle Scholar
  15. 15.
    Chou S Y, Krauss P R, Renstrom P J. Imprint lithography with 25-nanometer resolution. Science, 1996, 272(5258): 85–87CrossRefGoogle Scholar
  16. 16.
    Chou S Y, Keimel C, Gu J. Ultrafast and direct imprint of nano-structures in silicon. Nature, 2002, 417(6891): 835–837CrossRefGoogle Scholar
  17. 17.
    Madau M. Fundamentals of Microfabrication. Boca Raton: CRC Press, 1997Google Scholar
  18. 18.
    Suh J W, Glander S F, Darling R B, et al. Organic thermal and electrostatic ciliary microactuator array for object manipulation. Sensors and Actuators A, 1997, 58: 51–60CrossRefGoogle Scholar
  19. 19.
    Kohl M, Skrobanek K D, Miyazaki S. Development of stress-optimized shape memory microvalves. Sensors and Actuators A, 1999, 72: 243–250CrossRefGoogle Scholar
  20. 20.
    Fu Y, Du H, Huang W, et al. TiNi-based thin films in MEMS applications: a review. Sensors and Actuators A, 2004, 112: 395–408CrossRefGoogle Scholar
  21. 21.
    Hsu T R. MENS & Microsystems: Design and Manufacture. Beijing: McGraw-Hill Education Co. and China Machine Press, 2004. 127Google Scholar

Copyright information

© Science in China Press and Springer-Verlag GmbH 2009

Authors and Affiliations

  1. 1.Center for Nanoscale Science and Technology (CNST), College of Chemistry and Molecular EngineeringPeking UniversityBeijingChina
  2. 2.Nanotechnology Industrialization Base of ChinaTianjinChina

Personalised recommendations