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Maskless Single-Sided Wet Etching Process for the Fabrication of Ultra-Low Distortion Polyimide Membranes

Published online by Cambridge University Press:  21 February 2011

M. L. Schattenburg ,
R. I. Fuentes ,
G. Czernienko ,
R. C. Fleming  and
J. Porter
M. L. Schattenburg
Affiliation:
Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139.
R. I. Fuentes
Affiliation:
Materials and Technologies Corporation, 341 Sheafe Road, Poughkeepsie, NY 12601.
G. Czernienko
Affiliation:
Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139.
R. C. Fleming
Affiliation:
Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139.
J. Porter
Affiliation:
Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139.
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Abstract

A process for volume production of ultra-low distortion (<200 ppm), thin polyimide membranes on silicon wafers was developed using the RotoEtch™ dynamic fluid confinement tool. A critical advantage of the process is that it exposes the sample to the etching solution over a selected area on one side only, without contacting, wetting, or otherwise contaminating the front surface. This unique feature allows the etching away of a circular portion (over 40 mm diameter) of the backside of a patterned silicon wafer to form a freestanding thin polyimide membrane (<1 μim thick). The polyimide film is patterned prior to wet etching with a sub-micron period grating (200 nm period). The resulting distortion of the grating on the freestanding membrane is less than 200 ppm over the entire membrane area. This process seems ideally suited for instances—like the one above—when immersion, contacting, or contamination of one side of the sample would be impossible or impractical. It also allows backetching finished micro-structures that would otherwise be disturbed or destroyed by immersion in the fluid. Finally, it speeds up the fabrication of freestanding films since it does not require masking or any other form of front-side protection or backside lithographic steps. In this paper we report on a silicon through-etch process based on an HF:HNO3 acid mixture which typically forms membranes in only 10–20 minutes. Since polyimide easily distorts due to excessive heat or mechanical strain, the etching process needs to be carefully controlled. This process is also ideal for forming large membranes of other HF:HNO3-inert materials such as silicon carbide or diamond.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 356: Symposium B2 – Thin Films: Stresses and Mechanical Properties V , 1994 , 615
Copyright
Copyright © Materials Research Society 1995

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References

1. Markert, T.H., Bauer, J.M., Canizares, C.R., Isobe, T., Nenonen, S., O’Connor, J., Schattenburg, M.L., Flanagan, K., and Zombeck, M.V., in EUV, X-ray, and Gamma-Ray Instrumentation for Astronomy II (Proc. SPIE 1549), eds. Siegmund, O.H.W. and Rothschild, R.E. (SPIE, Bellingham, WA), 408–419 (1991).Google Scholar
2. Aucoin, R.J., Markert, T.H., Nenonen, S., Flanagan, K., and Barbera, M., in EUV, X-ray, and Gamma-Ray Instrumentation for Astronomy V (Proc. SPIE 2280), eds. Siegmund, O.H.W. and Vallerga, J.V. (SPIE, Bellingham, WA), 134–144 (1994).Google Scholar
3. Mutikainen, R., Viitanen, V.-P., and Nenonen, S., J. X-ray Sci. Technol. 4, 82 (1994).Google Scholar
4. Schattenburg, M.L., Anderson, E.H., and Smith, H.I., Physica Scripta 41, 13–20 (1990).Google Scholar
5. Schattenburg, M.L., Aucoin, R.J., Fleming, R.C., Plotnik, I., Porter, J., and Smith, H.I., in EUV, X-ray, and Gamma-Ray Instrumentation for Astronomy V (Proc. SPIE 2280), eds. Siegmund, O.H.W. and Vallerga, J. (SPIE, Bellingham, WA), 181–190 (1994).Google Scholar
6. Gong, B.M. and Ye, Y.D., J. Vac. Sci. Technol. 19, 1204–1207 (1981).Google Scholar
7. Wada, T., Sakurai, S., and Kawabuchi, K., J. Vac. Sci. Technol. 19, 1208–1210 (1981).Google Scholar
8. Huang, J.B. and Gong, B.M., J. Vac. Sci. Technol. B 3, 253–257 (1985).Google Scholar
9. Early, K., Schattenburg, M. L., and Smith, H. I., Microelectronic Engineering 11, 317–321 (1990).Google Scholar
10. Yen, A., Ghanbari, R. A., Ku, Y.-C., Chu, W., Schattenburg, M. L., Carter, J. M., and Smith, H. I., Microelectronic Engineering 13, 271–274 (1991).Google Scholar
11. Flanders, D.C., Ph.D. Thesis, Massachusetts Institute of Technology, 1978.Google Scholar
12. Hawryluk, A.M., Ph.D. Thesis, Massachusetts Institute of Technology, 1981.Google Scholar
13. Kaminski, G., J. Vac. Sci. Technol. B 4, 1015–1024 (1985).Google Scholar
14. Linde, H. and Austin, L., J. Electrochem. Soc. 139, 1170–1174 (1992).Google Scholar
15. Vossen, J.L. and Kem, W., Thin Film Processes (Academic Press, Orlando, FL, 1978), Chapter V-l.Google Scholar
16. SEZ America, Inc., 4824 South 40th St., Phoenix, AZ 85040.Google Scholar
17. Fuentes, R., J. Vac. Sci. Technol. B 10, 3159–3163 (1992).Google Scholar
18. Whitehair, S.D., Yehoda, J.E., Fuentes, R., Roy, R.A., Guarnieri, C.R., and Cuomo, J.J., in Materials Aspects of X-ray Lithography (MRS Symposium Proceedings 306), ed. Celler, G.K. and Maldonado, J.R., 97–102 (1993).Google Scholar
19. Markert, T.H., Canizares, C.R., Dewey, D., McGuirk, M., Pak, C., and Schattenburg, M.L., in EUV,X-ray, and Gamma-Ray Instrumentation for Astronomy V (Proc. SPIE 2280), eds. Siegmund, O. H. W and Vallerga, J. (SPIE, Bellingham, WA), 168–180 (1994).Google Scholar
20. Dewey, D., Humphries, D.N., McLean, G.Y., and Moschella, D.A., in EUV, X-ray, and Gamma-Ray Instrumentation for Astronomy V (Proc. SPIE 2280), eds. Siegmund, O. H. W. and Vallerga, J. (SPIE, Bellingham, WA), 257–271 (1994).Google Scholar