Abstract
The high porosity and uniform pore size of mesoporous oxide films offer unique opportunities for microelectromechanical system (MEMS) devices that require low density and low thermal conductivity. This paper provides the first report in which mesoporous films were adapted for MEMS applications. Mesoporous SiO2 and Al2O3 films were prepared by spin coating using block copolymers as the structure-directing agents. The resulting films were over 50% porous with uniform pores of 8-nm average diameter and an extremely smooth surface. The photopatterning and etching characteristics of the mesoporous films were investigated and processing protocols were established which enabled the films to serve as the sacrificial layer or the structure layer in MEMS devices. The unique mesoporous morphology leads to novel behavior including extremely high etching rates and the ability to etch underlying layers. Surface micromachining methods were used to fabricate three basic MEMS structures, microbridges, cantilevers, and membranes, from the mesoporous oxides.
Similar content being viewed by others
References
N.K. Raman, M.T. Anderson, and C.J. Brinker, Chem. Mater. 8, 1682 (1996).
D. Zhao, P. Yang, Q. Huo, B.F. Chmelka, and G.D. Stucky, Curr. Opin. Solid State Mater. Sci. 3, 111 (1998).
A. Van Blaaderen, R. Ruel, and P. Wiltzius, Nature 385, 321 (1997).
C.T. Kresge, M.E. Leonowicz, W.J. Roth, J.C. Vartuli, and J.S. Beck, Nature 359, 710 (1992).
P. Yang, D. Zhao, D.I. Margolese, B.F. Chmelka, and G.D. Stucky, Chem. Mater. 11, 2813 (1999).
H. Yang, G.A. Ozin, and C.T. Kresge, Adv. Mater. 10, 883 (1998).
D. Zhao, P. Yang, N. Melosh, J. Feng, B.F. Chmelka, and G.D. Stucky, Adv. Mater. 10, 1380 (1998).
Y. Lu, R. Ganguli, E.A. Drewien, M.T. Anderson, C.J. Brinker, W. Gong, Y. Guo, H. Soyez, B. Dunn, M.H. Huang, and J.I. Zink, Nature 389, 364 (1997).
D. Zhao, Q. Huo, J. Feng, B.F. Chmelka, and G.D. Stucky, J. Am. Chem. Soc. 120, 6042 (1998).
P. Yang, T. Deng, D. Zhao, P. Feng, D. Pine, B.F. Chmelka, G.M. Whitesides, and G.D. Stucky, Science 282, 2244 (1998).
P. Yang, G. Wirnsberger, H.C. Huang, S.R. Cordero, M.D. McGehee, B. Scott, T. Deng, G.M. Whitesides, B.F. Chmelka, S.K. Buratto, and G.D. Stucky, Science 287, 465 (2000).
R.C. Hayward, P. Alberius-Henning, B.F. Chmelka, and G.D. Stucky, Microporous Mesoporous Mater. 44–45, 619 (2001).
See the special issue of MRS Bull. April 2001: Microelectromechanical Systems: Technology and Applications, guest edited by D. Bishop, A. Heuer and D. Williams, p. 282.
(a) S. Besson, T. Gacoin, C. Jacquiod, C. Ricolleau, D. Babonneau, and J-P. Boilot, J. Mater. Chem. 10, 1331 (2000); (b) S. Besson, C. Ricolleau, T. Gacoin, C. Jacquiod, and J-P. Boilot, J. Phys. Chem. B 104, 12095 (2000).
D.J. Suh and T-J. Park, Chem. Mater. 9, 1903 (1997).
B. Chu and Z. Zhou, in Nonionic Surfactants: polyoxyalkylene block copolymers, edited by V.M. Nace (Marcel Dekker, New York, 1996), p. 67.
M. Born and E. Wolf, Principles of Optics (Pergamon Press, Oxford, U.K., 1986).
F. Mitschke, Opt. Lett. 14, 967 (1989).
J. Matsuoka, N. Kitamura, S. Fujinaga, T. Kitaoka, and H. Yamashita, J. Non-Cryst. Solids 135, 86 (1991).
N. Clark, MRS Bull. 26, 320 (2001).
I.H. Joe, A.K. Vasudevan, G. Aruldhas, A.D. Damodaran, and K.G.K. Warrier, J. Solid State Chem. 131, 181 (1997).
C. Guo, H.Z. Liu, and J.Y. Chen, Colloid Polym. Sci. 277, 376 (1999).
A. Bertoluzza, C. Fagnano, M.A. Morelli, V. Gottardi, and M. Guglielmi, J. Non-Cryst. Solids 48, 117 (1982).
N. Ozer, J.P. Cronin, Y.J. Yao, and A.P. Tomsia, Sol. Energy Mater. Sol. Cells 59, 355 (1999).
V.J. Silvestri, C.M. Osburn, and D.W. Ormond, J. Electrochem. Soc. 125, 902 (1978).
T. Yasuyuki and S.M. Tadashi, J. Vac. Sci. Technol., A 16, 2042 (1998).
M.J. Madou, Fundamentals of Microfabrication (CRC Press, New York, 1997).
K.R. Williams and R.S. Muller, J. Microelectromech. Syst. 5, 256 (1996).
S.D. Senturia, Microsystem Design (Kluwer Academic Publishers, Boston, MA, 2000).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Paik, JA., Fan, SK., Kim, CJ. et al. Micromachining of mesoporous oxide films for microelectromechanical system structures. Journal of Materials Research 17, 2121–2129 (2002). https://doi.org/10.1557/JMR.2002.0313
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1557/JMR.2002.0313