Abstract
Planar plasma etching of silicon for fabrication of deep trenches has been studied using the method of factorial design. A highly anisotropic etching profile with a slight positive slope is obtained using SF6, C2C1F5, and CH4 in the low energy plasma etch mode. The anisotropy is attributed to the polymerization of CH4 molecules with the active species in the plasma. The polymer is removed preferentially in the vertical direction by energetic ions from the plasma, leaving the polymer layer on the side wall to inhibit lateral etching of silicon. Good uniformity across the wafer and smooth trench surfaces are obtained with this process. Trench depths of greater than 3µm with less than 0.24µm of undercut are observed. Etch rate measurements were made and found to be greater than 1000 angstroms/minute. Selectivity over the oxide mask is greater than 15:1.
By using factorial design to statistically characterize this process, the effects of interactions between various process parameters are studied. Optimal etching conditions are obtained from the interaction terms for the process parameters. The ability to etch deep trenches with smooth surfaces, low damage, low linewidth degredation, and high selectivity make this process useful for many applications in VLSI devices.
Similar content being viewed by others
References
D. Bollinger, S. Lida, and O. Matsumoto. Solid State Technology 27, 6 (June 1984).
George E. P. Box, William G. Hunter, and J. Stuart Hunter. Statistics For Experimenters, (John Wiley & Sons, New York, 1978), pp. 306–328.
K.M. Cham and S.-Y. Chiang. IEEE Electron Device Letters EDL-4, 9 (September 1983).
K.Y. Chiu, J.L. Moll K.M. cham, J. Lin, C. Lage, S. Angelos, and R.L. Tillman. IEEE Trans, on Electron Devices ED-30, 11 (November 1983).
L.M. Ephrath and R.S. Bennett Journal of the Electrochemical Society 129, 8 (August 1982).
C. Gonzalez and J. P. McVittie. IEEE Electron Device Letters EDL-6, 5 (May 1985).
C. J. Heslop. Proceedings of the Fifth Symposium on Plasma Processing, (The Electrochemical Society, Inc., New Orleans, LA, October, 1984), pp. 134–141.
J.C. Hui, T.Y. Chiu, S.W.S. Wong, and W.G. Oldham. IEEE Trans. on Electron Devices ED-29, 4 (April 1982).
T. Ishijima and K. Terada. Symposium on VLSI — Proceedings, (IEEE, 1984), pp. 28–29.
H. Kalter and E.P.G.T. van de Ven. Philips tech. Rev. 38, 7/8 (1978/79).
J. P. McVittie and C. Gonzalez. Proceedings of the Fifth Symposium on Plasma Processing, (The Electrochemical Society, Inc., New Orleans, LA, October, 1984), pp. 552–567.
J. P. McVittie and T. A. Lin. To be published.
R.D. Rung, H. Momose, and Y. Nagakubo. IEDM Proceedings, (IEEE, 1982), pp. 237–240.
K. Minegishi, S. Nakajima, K. Miura, K. Harada, and T. Shibata. IEDM Proceedings, (IEEE, 1983), pp. 319–321.
T. Morie, K. Minegishi, and S. Nakajima. IEEE Electron Device Letters EDL-4, 11 (November 1983).
Shigeru Nakajima, Kazushige Minegishi, Kenji Miura, Takashi Morie, Masakatsu Kimizuka, and Tsuneo Mano. IEEE Journal of Solid-State Circuits SC-20, 1 (February 1985).
W.G. Oldham. IEDM Proceedings, (IEEE, 1982), pp. 216–219.
R.G. Poulsen. J. Vac. Sci. Technol. 14, 1 (Jan./Feb. 1977).
S. Satoh, M. Yoneda, M. Nagatomo, K. Fujishima, T. Yamazaki, and H. Nakata. Symposium on VLSI — Proceedings, (IEEE, 1984), pp. 18–19.
G.C. Schwartz and P.M. Schaible. J. Vac. Sci. Technol. 16, 2 (Mar./Apr. 1979).
H. Shichijo, Sanjay K. Banerjee, Satwinder D. S. Malhi, G. P. Pollack, William F. Richardson, D. M. Bordelon, Richard H. Womack, Mostafa Elahy, C.-P. Wang, James Gallia, H. E. Davis, A. H. Shah, and P. K. Chatterjee. IEEE Electron Device Letters EDL-7, 2 (February 1986).
J. E. Spencer, G. G. Bama, and D. E. Carter. Proceedings of the Fifth Symposium on Plasma Processing, (The Electrochemical Society, Inc., New Orleans, LA, October, 1984), pp. 413–423.
H. Sunami, T. Kure, N. Hashimoto, K. Itoh, T. Toyabe, and S. Asai. IEDM Proceedings, (IEEE, 1983), pp. 806–808.
Clarance W. Teng, Gordon Pollack, and W.R. Hunter. IEEE Journal of Solid-State Circuits SC-20, 1 (February 1985).
Hong-Hsiang Tsai, Chih-Lin Yu, and Ching-Yuan Wu. IEEE Electron Device Letters EDL-7, 2 (February 1986).
Hong-Hsiang Tsai, Shiao-Mo Chen, and Ching-Yuan Wu. IEEE Electron Device Letters EDL-7, 2 (February 1986).
E.D. Wolf, I. Adesida, and J.D. Chinn. J. Vac. Sci. Technol. 2, 2 (Apr.–June 1984).
Kikuo Yamabe and Kenji Taniguchi. IEEE Journal of Solid-State Circuits SC-20, 1 (February 1985).
T. Yamaguchi, S. Morimoto, G.H. Kawamoto, H.K. Park, and G.C. Eiden. IEDM Proceedings, (IEEE, 1983), pp. 522–525.
Tadanori Yamaguchi, Sciichi Morimoto, Hee Kyun Park, and Greg C. Eiden. IEEE Journal of Solid-State Circuits SC-20, 1 (February 1985).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Leeke, S.D., Liu, D.K.Y. & McVittie, J.P. Plasma Mode Trench Etching with Direct Hydrocarbon Injection. MRS Online Proceedings Library 68, 21–27 (1986). https://doi.org/10.1557/PROC-68-21
Published:
Issue Date:
DOI: https://doi.org/10.1557/PROC-68-21