Abstract
The effect of the CF4/C4F8 ratio in a CF4 + C4F8 + Ar mixture on the parameters of the gaseous phase of a low-pressure inductively coupled plasma, defining the kinetics and selectivity of etching in an SiO2/Si system, is investigated. It is found that increasing the SiO2/Si etching ratio, with an increase of the quantity of C4F8 in the plasma-forming mixture, is determined by various changes of the effective interaction probabilities for these materials. It is demonstrated that, within the investigated range of conditions, the kinetics of the formation of the fluorocarbon polymer film on the processed surface exerts a decisive influence on the character of the variation of the effective interaction probability. The interrelationships between the gas-phase and heterogeneous characteristics of the etching process are revealed.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Handbook of Plasma Processing Technology, Rossnagel, S.M., Cuomo, J.J. and Westwood, W.D., Eds. Park Ridge: Noyes, 1990.
Rooth, J.R., Industrial Plasma Engineering, Philadelphia: OP, 1995.
Roosmalen, A.J., Baggerman, J.A.G., and Brader, S.J.H., Dry Etching for VLSI, New York: Plenum, 1991.
Wolf, S. and Tauber, R.N., Silicon Processing for the VLSI Era, Vol. 1: Process Technology, New York: Lattice, 2000.
Lieberman, M.A. and Lichtenberg, A.J., Principles of Plasma Discharges and Materials Processing, New York: Wiley, 1994.
Kimura, T. and Ohe, K., Probe measurements and global model of inductively coupled Ar/CF4 discharges, Plasma Sources Sci. Technol., 1999, vol. 8, pp. 553–560.
Kimura, T. and Ohe, K., Model and probe measurements of inductively coupled CF4 discharges, J. Appl. Phys., 2002, vol. 92, pp. 1780–1787.
Efremov, A.M., Kim, D.-P., and Kim, C.-I., Effect of gas mixing ratio on gas-phase composition and etch rate in an inductively coupled CF4/Ar plasma, Vacuum, 2004, vol. 75, pp. 133–142.
Chun, I., Efremov, A., Yeom, G.Y., and Kwon, K.-H., A comparative study of CF4/O2/Ar and C4F8/O2/Ar plasmas for dry etching applications, Thin Solid Films, 2015, vol. 579, pp. 136–143.
Kokkoris, G., Goodyear, A., Cooke, M., and Gogolides, E., A global model for C4F8 plasmas cou-pling gas phase and wall surface reaction kinetics, J. Phys. D: Appl. Phys., 2008, vol. 41, p. 195211.
Vasenkov, A.V., Li, X., Oehrlein, G.S., and Kushner, M.J., discharges, J. Vac. Sci. Technol., A, 2004, vol. 22, pp. 511–530.
Sasaki, K., Kawai, Y., Suzuki, C., and Kadota, K., Absolute density and reaction kinetics of fluorine atoms in high-density c-C4F8 plasmas, J. Appl. Phys., 1998, vol. 83, pp. 7482–7487.
Son, J., Efremov, A., Yun, S.J., Yeom, G.Y., and Kwon, K.-H., Etching characteristics and mechanism of SiNx films for nano-devices in CH2F2/O2/Ar inductively coupled plasma: effect of O2 mixing ratio, J. Nanosci. Nanotechnol., 2014, vol. 14, pp. 9534–9540.
Johnson, E.O. and Malter, L., A floating double probe method for measurements in gas discharges, Phys. Rev., 1950, vol. 80, pp. 58–70.
Sugavara, M., Plasma Etching: Fundamentals and Applications, New York: Oxford Univ. Press, 1998.
Kwon, K.-H., Efremov, A., Kim, M., Min, N.K., Jeong, J., and Kim, K., A model-based analysis of plasma parameters and composition in HBr/X (X = Ar, He, N2) inductively coupled plasmas, J. Electrochem. Soc., 2010, vol. 157, pp. H574–H579.
Efremov, A., Min, N.K., Choi, B.G., Baek, K.H., and Kwon, K.-H., A model-based analysis of plasma parameters and active species kinetics in Cl2/X (X = Ar, He, N2) inductively coupled plasmas, J. Electrochem. Soc., 2008, vol. 155, pp. D777–D782.
Lee, J., Efremov, A., Lee, J., Yeom, G.H., and Kwon, K.-H., Silicon surface modification using C4F8 + O2 plasma for nano-imprint lithography, J. Nanosci. Nanotechnol., 2015, vol. 15, pp. 8749–8755.
Rauf, S. and Ventzek, P.L.G., discharge, J. Vac. Sci. Technol., A, 2002, vol. 20, pp. 14–23.
Sasaki, K., Kawai, Y., and Kadota, K., Determination of fluorine atom density in reactive plasmas by vacuum ultraviolet absorption spectroscopy at 95.85 nm, Rev. Sci. Instrum., 1999, vol. 70, pp. 76–81.
Gray, D.C., Tepermeister, I., and Sawin, H.H., Phenomenological modeling of ion enhanced surface kinetics in fluorine-based plasma etching, J. Vac. Technol. B, 1993, vol. 11, pp. 1243–1257.
Efremov, A.M., Kim, D.P., and Kim, C.-I., Simple model for ion-assisted etching using Cl2/Ar inductively coupled plasma: effect of gas mixing ratio, IEEE Trans. Plasma Sci., 2004, vol. 32, pp. 1344–1351.
Lee, C., Graves, D.B., and Lieberman, M.A., Role of etch products in polysilicon etching in a high-density chlorine discharge, Plasma Chem. Plasma Process., 1996, vol. 16, pp. 99–118.
Matsui, M., Tatsumi, T., and Sekine, M., Relationship of etch reaction and reactive species flux in C4F8-Ar-O2 plasma for SiO2 selective etching over Si and Si3N4, J. Vac. Sci. Technol., A, 2001, vol. 19, pp. 2089–2096.
Standaert, T.E.F.M., Hedlund, C., Joseph, E.A., and Oehrlein, G.S., Role of fluorocarbon film formation in the etching of silicon, silicondioxide, silicon nitride, and amorphous hydrogenated silicon carbide, J. Vac. Sci. Technol., A, 2004, vol. 22, pp. 53–60.
Li, X., Ling, L., Hua, X., Oehrlein, G.S., Wang, Y., and Anderson, H.M., Characteristics of C4F8 plasmas with Ar, Ne, and He additivesfor SiO2 etching in an inductively coupled plasma reactor, J. Vac. Sci. Technol., A, 2003, vol. 21, pp. 1955–1963.
Author information
Authors and Affiliations
Corresponding author
Additional information
Original Russian Text © A.M. Efremov, D.B. Murin, K.-H. Kwon, 2018, published in Mikroelektronika, 2018, Vol. 47, No. 4.
Rights and permissions
About this article
Cite this article
Efremov, A.M., Murin, D.B. & Kwon, KH. On the Effect of the Ratio of Concentrations of Fluorocarbon Components in a CF4 + C4F8 + Ar Mixture on the Parameters of Plasma and SiO2/Si Etching Selectivity. Russ Microelectron 47, 239–246 (2018). https://doi.org/10.1134/S1063739718040030
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1063739718040030