Plasma Parameters and Si/SiO2 Etching Kinetics in Mixtures of Fluorocarbon Gases with Argon and Helium

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Abstract

The comparative study of plasma electro-physical parameters, fluorine atom densities as well as Si and SiO2 etching kinetics in CF4 + Ar/He, CHF3 + Ar/He and C4F8 + Ar/He gas mixtures with variable (0–45% He) initial compositions was carried out. It was found that the substitution of Ar by He at constant fraction of fluorocarbon component a) disturbs electrons-related plasma characteristics; b) exhibits the very weal effect in the ion bombardment intensity; and c) causes a decrease in both Si and SiO2 etching rates together with the fluorine atom density. It was shown that the dominant etching mechanism is the heterogeneous chemical reaction while the effective reaction probability either increases (in CF4 plasma) or keeps the nearly constant value (in CHF3 and C4F8 plasmas) with increasing fraction of He in a feed gas. The mechanism providing above effects were suggested.

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About the authors

A. M. Efremov

Molecular Electronics Research Institute (MERI)

Author for correspondence.
Email: amefremov@mail.ru
Russian Federation, Zelenograd

V. B. Betelin

SRISA RAS

Email: amefremov@mail.ru
Russian Federation, Moscow

K. H. Kwon

Korea University

Email: amefremov@mail.ru
Korea, Republic of, Chochiwon

References

  1. Wolf S., Tauber R. N., Silicon Processing for the VLSI Era. Volume 1. Process Technology, New York: Lattice Press, 2000. ISBN0961672161, 9780961672164
  2. Roosmalen J., Baggerman J. A. G., and H. Brader S. J., Dry etching for VLSI, New-York: Plenum Press, 1991. ISBN978–0–306–43835–6
  3. Krasnikov G. Ya. Vozmozhnosti mikroelektronnyh tehnologii s topologicheskimi razmerami menee 5 nm // Nanoindustriya, 2020, V. 13, No. S5–1(102), pp. 13–19. https://doi.org/10.22184/1993–8578.2020.13.5s.13.19
  4. Nojiri K. Dry etching technology for semiconductors, Tokyo: Springer International Publishing, 2015. ISBN978–3–319–10294–8
  5. Lieberman M. A., Lichtenberg A. J., Principles of plasma discharges and materials processing, New York: John Wiley & Sons Inc., 1994. ISBN9780471720010
  6. Kay E., Coburn J., Dilks A., Plasma chemistry of fluorocarbons as related to plasma etching and plasma polymerization // In: Veprek S., Venugopalan M. (eds) Plasma Chemistry III. Topics in Current Chemistry, vol. 94, Berlin, Heidelberg: Springer, 1980. https://doi.org/10.1007/BFb0048585
  7. Stoffels W. W., Stoffels E., Tachibana K., Polymerization of fluorocarbons in reactive ion etching plasmas // J. Vac. Sci. Tech. A., 1998, vol. 16, pp. 87–95. https://doi.org/10.1116/1.581016
  8. Standaert T.E.F.M., Hedlund C., Joseph E. A., Oehrlein G. S., Dalton T. J., Role of fluorocarbon film formation in the etching of silicon, silicon dioxide, silicon nitride, and amorphous hydrogenated silicon carbide // J. Vac. Sci. Technol. A., 2004, vol. 22, pp. 53–60. https://doi.org/10.1116/1.1626642
  9. Schaepkens M., Standaert T. E. F. M., Rueger N. R., Sebel P. G. M., Oehrlein G. S., Cook J. M., Study of the SiO2-to-Si3N4 etch selectivity mechanism in inductively coupled fluorocarbon plasmas and a comparison with the SiO2-to-Si mechanism // J. Vac. Sci. Technol. A., 1999, vol. 17, pp. 26–37. https://doi.org/10.1116/1.582108
  10. Efremov A. M., Murin D. B., Kwon K.-H., Concerning the Effect of Type of Fluorocarbon Gas on the Output Characteristics of the Reactive-Ion Etching Process // Russian Microelectronics, 2020, vol. 49, No. 3, pp. 157–165. https://doi.org/10.1134/S1063739720020031
  11. Efremov A. M., Murin D. B., Kwon K.-H., Features of the Kinetics of Bulk and Heterogeneous Processes in CHF3 + Ar and C4F8 + Ar Plasma Mixtures, Russian Microelectronics, 2019, vol. 48, No. 2, pp. 119–127. https://doi.org/10.1134/S1063739719020070
  12. Kimura T., Ohe K., Probe measurements and global model of inductively coupled Ar/CF4 discharges // Plasma Sources Sci. Technol., 1999, vol. 8, p. 553–561. https://doi.org/10.1088/0963–0252/8/4/305
  13. Rauf S., Ventzek P. L., Model for an inductively coupled Ar/c-C4F8 plasma discharge // J. Vac. Sci. Technol. A., 2002, vol. 20, pp. 14–23. http://dx.doi.org/10.1116/1.1417538
  14. Proshina O., Rakhimova T. V., Zotovich A., Lopaev D. V., Zyryanov S. M., Rakhimov A. T., Multifold study of volume plasma chemistry in Ar/CF4 and Ar/CHF3 CCP discharges // Plasma Sources Sci. Technol., 2017, vol. 26, p. 075005(1–18). http://dx.doi.org/10.1088/1361–6595/aa72c9
  15. Efremov A., Lee B. J., Kwon K.-H., On relationships between gas-phase chemistry and reactive-ion etching kinetics for silicon-based thin films (SiC, SiO2 and SixNy) in multi-component fluorocarbon gas mixtures // Materials, 2021, vol. 14, pp. 1432(1–27). http://dx.doi.org/10.3390/ma14061432
  16. Efremov A., Son H. J., Choi G., Kwon K.-H., On Mechanisms Influencing Etching/Polymerization Balance in Multi-Component Fluorocarbon Gas Mixtures // Vacuum, 2022, vol. 206, p. 111518(1–10). https://doi.org/10.1016/j.vacuum.2022.111518
  17. Choi G., Efremov A., Son H. J., Kwon K.-H., Noble gas effect on ACL etching selectivity to SiO2 films // Plasma Processes and Polymers, 2023, vol. 20, No. 8, p. e2300026 (1–9). http://dx.doi.org/10.1002/ppap.202300026
  18. Choi G., Efremov A., Lee D.-K., Cho C.-H., Kwon K.-H., On Mechanisms to Control SiO2 Etching Kinetics In Low-Power Reactive-Ion Etching Process Using CF4 + C4F8 + Ar + He Plasma // Vacuum, 2023, vol. 216, p. 112484(1–10). https://doi.org/10.1016/j.vacuum.2023.112484
  19. Mutsukura N., Shimada M., Plasma diagnostics and processings in CF4/He radio frequency discharge // J. Vac. Sci. Technol. A, 1997, vol. 15, p. 1828–1831. https://doi.org/10.1116/1.580799
  20. Iwase K., Selvin P. C., Sato G., Fujii T., Mass spectrometric studies of ionic products in CF4/He and CF4/O2/He microwave discharge plasmas // J. Phys. D: Appl. Phys., 2002, vol. 35, p. 1934–1945. https://doi.org/10.1088/0022-3727/35/16/306
  21. Shun’ko E. V., Langmuir Probe in Theory and Practice, Boca Raton: Universal Publishers, 2008. ISBN1599429357, 9781599429359
  22. Lopaev D. V., Volynets A. V., Zyryanov S. M., Zotovich A. I., Rakhimov A. T. Actinometry of O, N and F atoms // J. Phys. D: Appl. Phys. 2017. V. 50. pp. 075202 (1–17). https://doi.org/10.1088/1361-6463/50/7/075202
  23. Gottscho R. A., Miller T. A., Optical techniques in plasma diagnostics // Pure Appl. Chem., 1984, vol. 56, No.2, p. 189–208. https://doi.org/10.1364/OAM.1989.WY1
  24. Gray D. C., Tepermeister I., Sawin H. H., Phenomenological modeling of ion-enhanced surface kinetics in fluorine-based plasma-etching // J. Vac. Sci. Technol. B., 1993, vol. 11, p. 1243–1257. https://doi.org/10.1116/1.586925
  25. Seah M. P., Nunney T. S., Sputtering yields of compounds using argon ions // J. Phys. D: Appl. Phys., 2010, vol. 43, No. 25, pp. 253001(1–24).
  26. Coburn J.W., Plasma etching and reactive ion etching, New York: AVS Monograph Series, 1982. https://doi.org/10.1088/0022-3727/43/25/253001
  27. Donnelly V. M., Kornblit A., Plasma etching: Yesterday, today, and tomorrow // J. Vac. Sci. Technol. A, 2013, vol. 31, No. 5, p. 050825(1–48). https://doi.org/10.1116/1.4819316
  28. Efremov A. M., Betelin V. B., Kwon K.-H., On the Mechanisms Regulating the Plasma Composition and Kinetics of Heterogeneous Processes in a CF4 + CHF3 + Ar Mixture // Russian Microelectronics, 2022, Vol. 51, No. 5, p. 302–310. https://doi.org/10.1134/S1063739722050055
  29. Efremov A. M., Betelin V. B., Mednikov K. A., Kwon K.-H., Gas-phase parameters and reactive-ion etching regimes for Si AND SiO2 in binary Ar + CF4/C4F8 mixtures // ChemChemTech, 2021, V. 64, No. 6, pp. 25–34. https://doi.org/10.6060/ivkkt.20216406.6377
  30. Ho P., Johannes J. E., Buss R. J., Modeling the plasma chemistry of C2F6 and CHF3 etching of silicon dioxide, with comparisons to etch rate and diagnostic data // J. Vac. Sci. Technol. B, 2001, vol. 19, p. 2344–2363. https://doi.org/10.1116/1.1387048
  31. Vasenkov A. V., Li X., Oehlein G. S., Kushner M. J., Properties of c-C4F8 inductively coupled plasmas. II. Plasma chemistry and reaction mechanism for modeling of Ar/c-C4F8/O2 discharges // J. Vac. Sci. Technol A, 2004, vol. 22, p. 511–530. https://doi.org/10.1116/1.1697483

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2. Fig. 1. Electron temperature (a), ion current density (b), negative displacement on the treated surface (c), and the parameter tracking the change in ion bombardment intensity (d) in CF4 + Ar/He, CHF3 + Ar/He, and C4F8 + Ar/He mixtures as a function of helium content in the plasma gas.

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3. Fig. 2. Emission intensities of analytical lines (a, b, c) and fluorine atom concentrations (d) in CF4 + + Ar/He, CHF3 + Ar/He, and C4F8 + Ar/He mixtures as a function of helium content in the plasma gas.

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4. Fig. 3. Etching rate (a, c, e) and effective probability of heterogeneous chemical reaction (b, d, f) in CF4 + Ar/He, CHF3 + Ar/He, and C4F8 + Ar/He mixtures as a function of helium content in the plasma gas. The dotted lines in Figs. a), c), and e) represent the chemical component of the etching rate.

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