Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-19T09:21:21.855Z Has data issue: false hasContentIssue false

In Situ Ftir Investigations of Polymer Surface Modification in Downstream Microwave Plasma Etching

Published online by Cambridge University Press:  22 February 2011

Jihperng Leu
Affiliation:
Department of Chemical Engineering and Material Science, University of Minnesota
K.F. Jensen
Affiliation:
Department of Chemical Engineering and Material Science, University of Minnesota
Get access

Abstract

In situ Fourier transform infrared (FTIR) reflection-absorption spectroscopy investigations of etching of thin polyimide and poly(methyl methacrylate) films (200-1500Å) in downstream microwave NF3/O2/Ar plasmas are reported. Etch rates and surface chemistry are monitored as a function of gas phase composition, plasma treatment conditions and time. NF3/Ar plasma treatment leads to significant surface fluorination characterized by the formation of aliphatic fluorine compounds (CFx), acyl fluorides, benzoyl fluoride, and polyfluorinated benzene. Addition of oxygen to the etching gas reduces the degree of surface fluorination and modifies the chemical structure. The absorption bands due to CFx structures decrease gradually while polyfluorinated benzene rings and benzoyl fluoride are absent for NF3/O2 mixtures with more than 20% oxygen. The effect of humidity on the plasma-modified polymers is studied by comparing infrared spectra collected in situ with those after air exposure. For NF3/O2 plasma-treated polyimides significant changes are observed while samples fluorinated in NF3 show no changes after exposure to air overnight. The FTIR data are supplemented by XPS analysis.

Type
Research Article
Copyright
Copyright © Materials Research Society 1989

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Lee, Y. K. and Craig, J. D., in Polymer Materials for Electronic Applications, edited by Feit, E.D. and Wilkins, C.W. Jr., (ASC Symposium Series 184, American Chemical Society, 1982), p.107.Google Scholar
2. Rohde, O., Riediker, M., Schaffner, A., and Bateman, J., Solid State Technol. 9, 109 (1986).Google Scholar
3. Chou, N. J., Parazsczak, J., Babich, E., Chaug, Y. S., and Goldblatt, R., Microelectronic Engineering 5, 375 (1986).Google Scholar
4. Vukanovic, V., Takacs, G. A., Matuszak, E. A., Egitto, F. D., Emmi, F., and Horwath, R. S., J. Vac. Sci. Technol. B6, 66 (1988).Google Scholar
5. Robinson, B. and Shivashankar, S. A., in Proceedinas of the Fifth Plasma Svmtosium (Electrochemical Society, New York, 1984), p. 206.Google Scholar
6. Egitto, F. D., Emmi, F., Horwath, R. S., and Vukanovic, V., J. Vac. Sci. Technol. B3, 893 (1985).Google Scholar
7. Kogoma, M. and Turban, G., Plasma Chem. and Plasma Proc. 6, 349 (1986).Google Scholar
8. Cain, S. R., Egitto, F. D., and Emmi, F., J. Vac. Sci. Technol. A5, 1576 (1987).Google Scholar
9. Fehsenfeld, F. C., Evenson, K. M., and Broida, H. P., Review of Scientific Instruments 36, 294 (1965).Google Scholar
10. Baise, A. I., J. Appl. Polym. Sci. 32, 4043 (1986).Google Scholar
11. Vasile, M. J., Richardson, T. J., Stevie, F. A., and Falconer, W. E., J. Chem. Soc. Dalton 4, 351 (1976).Google Scholar
12. Adcock, J. L., Inoue, S., and Lagow, R. J., J. Amer. Chem. Soc. 100, 1948 (1978).Google Scholar
13. Brown, J. K. and Morgan, K. J., in Advances in Fluorine Chemistry, Vol. 4, edited by Stacey, M., Tatlowand, J.C. and Sharpeed, A.G. (Butterworths, Washington, D. C., 1965), pp 253313.Google Scholar
14. Appleman, E. H., Mendelsohn, M. H., and Kim, H., J. Am. Chem. Soc. 107, 6515 (1985).Google Scholar
15. Cross, A. D., Introduction to Practical Infrared Spectroscopy, 2nd ed. (Butterworths, Washington, D. C., 1964), p. 79.Google Scholar
16. Otsuka, A. J. and Lagow, R. J., J. Fluorine Chemistry 4, 371 (1974).Google Scholar
17. Leu, J. and Jensen, K.F., unpublished data.Google Scholar
18. Dunn, D., Grant, J.L., and McClure, D.J., J. Vac. Sci. Technol. A7 (1989). (in press)Google Scholar
19. Yadav, R. A., Ram, S., Shanker, R., and Singh, S., Spectrochim. Acta, 43A, 901 (1987).Google Scholar
20. Varsanyi, G., Assianments for Vibrational Spectra of Seven Hundred Benzene Derivatives, Vol. 1 (John Wiley & Sons, New York, 1974).Google Scholar
21. Turban, G. and Rapeaux, M., J. Electrochem. Soc. 130, 2231 (1983).Google Scholar
22. Clark, D. T. and Shuttleworth, D., J. Polym. Sci. Polym. Chem. Ed. 18, 27 (1980).Google Scholar
23. Leary, H. J. and Campbell, D. S., in Photon. Electron. and Ion Probes of Polymer Structure and Prtrie, edited by Wright, D.W., Fabish, T.J., and Thomas, H.R. (ACS Symposium Series 162, American Chemical Society, Washington, D.C., 1981), pp. 419433.Google Scholar
24. Haszeldine, R. N., J. Chem. Soc. 4, 4026 (1954).Google Scholar
25. Chambers, R. D., Fluorine in Oreanic Chemistry (John Wiley & Sons, New York, 1973), p.107.Google Scholar