The Influence of Small F2, H2, and HF Additives on the Concentration of Active Particles in Tetrafluoromethane Plasma

A. M. Efremov; Ефремов А. М.; S. A. Smirnov; Смирнов С. А.; V. B. Betelin; Бетелин В. Б.

doi:10.31857/S0544126923700540

The Influence of Small F2, H2, and HF Additives on the Concentration of Active Particles in Tetrafluoromethane Plasma

Authors: Efremov A.M.¹^,2, Smirnov S.A.¹^,2, Betelin V.B.²
Affiliations:
1. Ivanovo State University of Chemistry and Technology
2. Federal State Institution “Federal Scientific Center Research Institute for System Research,” Russian Academy of Sciences
Issue: Vol 52, No 5 (2023)
Pages: 383-389
Section: ПЛАЗМЕННЫЕ ТЕХНОЛОГИИ
URL: https://journals.rcsi.science/0544-1269/article/view/138565
DOI: https://doi.org/10.31857/S0544126923700540
EDN: https://elibrary.ru/QCCCRC
ID: 138565

Cite item

Full Text

Open Access
Restricted Access

Access granted
Restricted Access

Subscription Access

Abstract
About the authors
References
Supplementary files
Statistics

Abstract

A comparative study of the effect of small (up to 20%) substituting additives F2, H2, and HF on the kinetics and stationary concentrations of neutral particles in 50% CF4 + 50% Ar plasma under the typical conditions of reactive ion etching (RIE) of silicon and its compounds is carried out. It is shown that the vari-ation of the CF4/F2 and CF4/H2 ratios leads to opposite, interrelated, and nonadditive changes in the con-centrations of fluorine atoms and fluorocarbon radicals. This provides wide ranges of regulation of the etch-ing rate and polymerization capacity with the minimal disturbance of the parameters of the electronic and ionic components of the plasma. In contrast, the CF4/HF relation has the minimal effect on the rate of sur-face polymerization, but noticeably changes the concentration of fluorine atoms. Thus, there is a selective effect on the rate of the heterogeneous chemical reaction.

Keywords

fluorocarbon gases, plasma, fluorine atoms, polymer-forming radicals, etching, polymerization, kinetics, mechanism

References

Nojiri K. Dry etching technology for semiconductors, Tokyo: Springer International Publishing, 2015.
Wolf S., Tauber R.N. Silicon Processing for the VLSI Era. Volume 1. Process Technology, New York: Lattice Press, 2000.
Roosmalen J., Baggerman J.A.G., H. Brader S.J. Dry etching for VLSI, New-York: Plenum Press, 1991.
Lieberman M.A., Lichtenberg A.J. Principles of plasma discharges and materials processing, New York: John Wiley & Sons Inc., 1994.
Stoffels W.W., Stoffels E., Tachibana K. Polymerization of fluorocarbons in reactive ion etching plasmas // J. Vac. Sci. Tech. A. 1998. V. 16. P. 87–95.
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. V. 22. P. 53–60.
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, V. 17. P. 26–37.
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. V. 94. Berlin, Heidelberg: Springer, 1980.
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. V. 49. № 3. P. 157–165.
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. V. 14. P. 1432(1–27).
Efremov A., Son H.J., Choi G., Kwon K.-H. On Mechanisms Influencing Etching/Polymerization Balance in Multi-Component Fluorocarbon Gas Mixtures // Vacuum. 2022. V. 206. P. 111518(1–10).
Knizikevicius R. Real dimensional simulation of SiO2 etching in CF4 + H2 plasma // Appl. Surface Sci. 2004. V. 222. P. 275–285.
Gorobchuk A. Numerical modeling of silicon processing technology in CF4/H2 plasma, 2015 International Siberian Conference on Control and Communications (SIBCON), Omsk, Russia, 2015. P. 1–4.
Marra D.C., Aydil E. S. Effect of H2 addition on surface reactions during CF4/H2 plasma etching of silicon and silicon dioxide films // J. Vac. Sci. Technol. A. 1997. V. 15. P. 2508–2517.
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. V. 48. № 2. P. 119–127.
Kimura T., Ohe K. Probe measurements and global model of inductively coupled Ar/CF4 discharges // Plasma Sources Sci. Technol. 1999. V. 8. P. 553–561.
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. V. 19. P. 2344–2352.
Shun’ko E.V. Langmuir Probe in Theory and Practice, Boca Raton: Universal Publishers, 2008.
Cunge G., Ramos R., Vempaire D., Touzeau M., Neijbauer M., Sadeghi N. Gas temperature measurement in CF4, SF6, O2, Cl2, and HBr inductively coupled plasmas // J. Vac. Sci. Technol. A. 2009. V. 27. № 3. P. 471–478.
Kokkoris G., Goodyear A., Cooke M., Gogolides E. A global model for C4F8 plasmas coupling gas phase and wall surface reaction kinetics // J. Phys. D. Appl. Phys. 2008. V. 41. P. 195211 (1–12).
Rauf S., Ventzek P.L. Model for an inductively coupled Ar/c-C4F8 plasma discharge // J. Vac. Sci. Technol. A. 2002. V. 20. P. 14–23.
Coburn J.W. Plasma etching and reactive ion etching, New York: AVS Monograph Series, 1982.
Derkach V.P., Bagrii I.P., Chechko G.A. Modeling of plasma etching in microelectronics // Cybern. Syst. Anal. 1990. V. 26. P. 653–663.
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. V. 11. P. 1243–1257.
Kimura T., Noto M. Experimental study and global model of inductively coupled CF4/O2 discharges // J. Appl. Phys. 2006. V. 100. P. 063303 (1–9).
Plumb I.C., Ryan K.R. A model of the chemical processes occurring in CF4/O2 discharges used in plasma etching // Plasma Chem. Plasma Process. 1986. V. 6. P. 205–230.
Efremov A., Lee J., Kim J. On the Control of Plasma Parameters and Active Species Kinetics in CF4 + O2 + Ar Gas Mixture by CF4/O2 and O2/Ar Mixing Ratios // Plasma Chem. Plasma Process. 2017. V. 37. P. 1445–1462.
d’Agostino R., Flamm D.L. Plasma etching of Si and SiO2 in SF6–O2 mixtures // J. Appl. Phys. 1981. V. 52. P. 162–167.
Jung J.H., Oh H., Shong B. Fluorination of TiN, TiO2, and SiO2 surfaces by HF toward selective atomic layer etching (ALE) // Coatings. 2023. V. 13. P. 387(1–11).