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A Comparison of CF4, CHF3 and C4F8 + Ar/O2 Inductively Coupled Plasmas for Dry Etching Applications

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Abstract

In this work, we performed the comparative study of plasma parameters, steady-state gas phase compositions and Si reactive-ion etching kinetics in CF4 + O2 + Ar, CHF3 + O2 + Ar and C4F8 + O2 + Ar gas mixtures with variable O2/Ar component ratios. It was found that the substitution of Ar for O2 (a) did not disturb the well-known correlation between the polymerizing ability and the F/C ratio in the original fluorocarbon molecule; (b) causes similar changes in electrons- and ions-related plasma parameters (electron temperature, plasma density, ion bombardment energy); and (c) always suppresses densities of polymerizing radicals and reduces the polymer film thickness. At the same time, the specific effects of oxygen on F atom kinetics result in sufficient differences in their densities and fluxes. It was shown that the dominant etching mechanism for Si in all three gas systems is the chemical etching pathway provided by F atoms (since the contribution of physical sputtering is below 10%) while measured etching rates do not follow the behavior of F atom flux. The phenomenological analysis of heterogeneous process kinetics allowed one to suggest factors influencing the effective reaction probability. These are either the transport of F atoms through thick polymer film (in the case of high-polymerizing C4F8 + O2 + Ar plasma) or heterogeneous reactions with a participation of oxygen atoms under the condition of thin or non-continuous polymer film (in the case of low-polymerizing CF4 + O2 + Ar plasma).

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References

  1. Sze SM (1988) VLSI technology. McGraw-Hill, New York

    Google Scholar 

  2. Sugano T (1990) Applications of plasma processes to VLSI technology. Wiley, New York

    Google Scholar 

  3. Rooth JR (1995) Industrial plasma engineering. IOP Publishing LTD, Philadelphia

    Book  Google Scholar 

  4. Wlof S, Tauber RN (2000) Silicon processing for the VLSI era. Volume 1. Process technology. Lattice Press, New York

    Google Scholar 

  5. Lieberman MA, Lichtenberg AJ (1994) Principles of plasma discharges and materials processing. Wiley, New York

    Google Scholar 

  6. Roosmalen AJ, Baggerman JAG, Brader SJH (1991) Dry etching for VLSI. Plenum Press, New-York

    Book  Google Scholar 

  7. Kimura T, Noto M (2006) Experimental study and global model of inductively coupled CF4/O2 discharges. J Appl Phys 100:063303

    Article  CAS  Google Scholar 

  8. Kimura T, Ohe K (1999) Probe measurements and global model of inductively coupled Ar/CF4 discharges. Plasma Sour Sci Technol 8:553

    Article  CAS  Google Scholar 

  9. Chun I, Efremov A, Yeom GY, Kwon K-H (2015) A comparative study of CF4/O2/Ar and C4F8/O2/Ar plasmas for dry etching applications. Thin Solid Films 579:136

    Article  CAS  Google Scholar 

  10. Efremov A, Lee J, Kim J (2017) 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 37:1445

    Article  CAS  Google Scholar 

  11. Ho P, Johannes JE, Buss RJ (2001) 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 19:2344

    Article  CAS  Google Scholar 

  12. Efremov AM, Murin DB, Kwon K-H (2018) Parameters of plasma and kinetics of active particles in CF4(CHF3) + Ar mixtures of a variable initial composition. Russ Microlectron 47:371

    Article  CAS  Google Scholar 

  13. Efremov AM, Murin DB, Kwon K-H (2020) Plasma parameters and kinetics of active particles in the mixture CHF3 + O2 + Ar. Russ Microlectron 49:233

    Article  CAS  Google Scholar 

  14. Kokkoris G, Goodyear A, Cooke M, Gogolides E (2008) A global model for C4F8 plasmas coupling gas phase and wall surface reaction kinetics. J Phys D Appl Phys 41:195211

    Article  CAS  Google Scholar 

  15. Rauf S, Ventzek PL (2002) Model for an inductively coupled Ar/c-C4F8 plasma discharge. J Vac Sci Technol A 20:14

    Article  CAS  Google Scholar 

  16. Lim N, Efremov A, Kwon K-H (2019) Gas-phase chemistry and etching mechanism of SiNx thin films in C4F8 + Ar inductively coupled plasma. Thin Solid Films 685:97–110

    Article  CAS  Google Scholar 

  17. Lee BJ, Efremov A, Nam Y, Kwon K-H (2020) Plasma parameters and silicon etching kinetics in C4F8 + O2 + Ar gas mixture: effect of component mixing ratios. Plasma Chem Plasma Process 40:1365–1380

    Article  CAS  Google Scholar 

  18. Schaepkens M, Standaert TEFM, Rueger NR, Sebel PGM, Oehrlein GS, Cook JM (1999) 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 17:26

    Article  CAS  Google Scholar 

  19. Matsui M, Tatsumi T, Sekine M (2001) 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 19:2089

    Article  CAS  Google Scholar 

  20. Standaert TEFM, Hedlund C, Joseph EA, Oehlein GS, Dalton TJ (2004) Role of fluorocarbon film formation in the etching of silicon, silicon dioxide, silicon nitride, and amorphous hydrogenated silicon carbide. J Vac Sci Technol A 22:53

    Article  CAS  Google Scholar 

  21. Kastenmeier BEE, Matsuo PJ, Oehrlein GS (1999) Highly selective etching of silicon nitride over silicon and silicon dioxide. J Vac Sci Technol A 17:3179

    Article  CAS  Google Scholar 

  22. Lele C, Liang Z, Linda X, Dongxia L, Hui C, Tod P (2009) J Semicond 30:033005

    Article  CAS  Google Scholar 

  23. Li X, Ling L, Hua X, Fukasawa M, Oehrlein GS, Barela M, Anderson HM (2003) Effects of Ar and O2 additives on SiO2 etching in C4F8-based plasmas. J Vac Sci Technol A 21:284

    Article  CAS  Google Scholar 

  24. Son J, Efremov A, Chun I, Yeom GY, Kwon K-H (2014) On the LPCVD-formed SiO2 etching mechanism in CF4/Ar/O2 inductively coupled plasmas: effects of gas mixing ratios and gas pressure. Plasma Chem Plasma Process 34:239

    Article  CAS  Google Scholar 

  25. Lee J, Efremov A, Yeom GY, Lim N, Kwon K-H (2015) Application of Si and SiO2 etching mechanisms in CF4/C4F8/Ar inductively coupled plasmas for nanoscale patterns. J Nanosci Nanotechnol 15:8340

    Article  CAS  PubMed  Google Scholar 

  26. Efremov A, Murin D, Kwon K-H (2020) Concerning the effect of type of fluorocarbon gas on the output characteristics of the reactive-ion etching process. Russ Microlectron 49:157

    Article  CAS  Google Scholar 

  27. Shun’ko EV, (2008) Langmuir probe in theory and practice. Universal Publishers, Boca Raton

    Google Scholar 

  28. Vasenkov AV, Li X, Oehlein GS, Kushner MJ (2004) 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 22:511

    Article  CAS  Google Scholar 

  29. Lee C, Lieberman MA (1995) Global model of Ar, O2, Cl2, and Ar/O2 high density plasma discharges. J Vac Sci Technol A 13:368

    Article  CAS  Google Scholar 

  30. Hsu CC, Nierode MA, Coburn JW, Graves DB (2006) Comparison of model and experiment for Ar, Ar/O2 and Ar/O2/Cl2 inductively coupled plasmas. J Phys D Appl Phys 39:3272

    Article  CAS  Google Scholar 

  31. Chistophorou LG, Olthoff JK (2004) Fundamental electron interactions with plasma processing gases. Springer, New York

    Book  Google Scholar 

  32. Efremov A, Lee J, Kwon K-H (2017) A comparative study of CF4, Cl2 and HBr + Ar inductively coupled plasmas for dry etching applications. Thin Solid Films 629:39

    Article  CAS  Google Scholar 

  33. Proshina O, Rakhimova TV, Zotovich A, Lopaev DV, Zyryanov SM, Rakhimov AT (2017) Multifold study of volume plasma chemistry in Ar/CF4 and Ar/CHF3 CCP discharges. Plasma Sources Sci Technol 26:075005

    Article  CAS  Google Scholar 

  34. Takahashi K, Hori M, Goto T (1994) Characteristics of fluorocarbon radicals and CHF3 molecule in CHF3 electron cyclotron resonance downstream plasma. Jpn J Appl Phys 33:4745

    Article  CAS  Google Scholar 

  35. Sasaki K, Kawai Y, Kadota K (1999) Determination of fluorine atom density in reactive plasmas by vacuum ultraviolet absorption spectroscopy at 95.85 nm. Rev Sci Instrum 70:76–81

    Article  CAS  Google Scholar 

  36. Kim DK, Kim YK, Lee H (2007) A study of the role of HBr and oxygen on the etch selectivity and the post-etch profile in a polysilicon/oxide etch using HBr/O2 based high density plasma for advanced DRAMs. Mater Sci Semicond Process 10:41

    Article  CAS  Google Scholar 

  37. d’Agostino R, Flamm DL (1981) Plasma etching of Si and SiO2 in SF6-O2 mixtures. J Appl Phys 52:162

    Article  Google Scholar 

  38. Knizikevicius R (2010) Simulations of Si and SiO2 Etching in SF6 + O2 Plasma. Acta Phys Pol A 117:478

    Article  CAS  Google Scholar 

  39. Mellhaoui X, Dussarta R, Tillocher T, Lefaucheux P, Ranson P (2005) SiOxFy passivation layer in silicon cryoetching. J Appl Phys 98:104901

    Article  CAS  Google Scholar 

  40. Pereira J, Pichon LE, Dussart R, Cardinaud C, Duluard CY, Oubensaid EH, Lefaucheux P, Boufnichel M, Ranson P (2009) In situ x-ray photoelectron spectroscopy analysis of SiOxFy passivation layer obtained in a SF6/O2 cryoetching process. Appl Phys Lett 94:071501

    Article  CAS  Google Scholar 

  41. Mullins CB, Coburn JW (1994) Ion-beam-assisted etching of Si with fluorine at low temperatures. J Appl Phys 76:7562

    Article  CAS  Google Scholar 

  42. Chevolleau T, Tessier PY, Cardinaud C, Turban G (1997) Etching of Si at low temperatures using a SF6 reactive ion beam: Effect of the ion energy and current density. J Vac Sci Technol A 15:2661

    Article  CAS  Google Scholar 

  43. Yeom GY, Kushner MJ (1990) Si/SiO2 etch properties using CF4 and CHF3 in radio frequency cylindrical magnetron discharges. Appl Phys Lett 56:857

    Article  CAS  Google Scholar 

  44. Gatzert C, Blakers AW, Deenapanray PNK, Macdonald D, Auret FD (2006) Investigation of reactive ion etching of dielectrics and Si in CHF3/O2 or CHF3/Ar for photovoltaic applications. J Vac Sci Technol A 24:1857

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was supported by the Industrial Technology Innovation Program (20009818, Development of plasma realtime process monitoring sensor and process simulation technology) funded by the Ministry of Trade, Industry and Energy (MOTIE, Republic of Korea) (N. Lim and K.-H. Kwon).

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Authors and Affiliations

  1. Department of Control and Instrumentation Engineering, Korea University, Sejong, 30019, Republic of Korea

    Nomin Lim & Kwang-Ho Kwon

  2. Department of Electronic Devices and Materials Technology, State University of Chemistry and Technology, 7 Sheremetevsky av., Ivanovo, Russia, 153000

    Alexander Efremov

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  1. Nomin Lim
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  2. Alexander Efremov
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  3. Kwang-Ho Kwon
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Correspondence to Kwang-Ho Kwon.

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Lim, N., Efremov, A. & Kwon, KH. A Comparison of CF4, CHF3 and C4F8 + Ar/O2 Inductively Coupled Plasmas for Dry Etching Applications. Plasma Chem Plasma Process 41, 1671–1689 (2021). https://doi.org/10.1007/s11090-021-10198-z

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