A comparative study of CF4/O2/Ar and C4F8/O2/Ar plasmas for dry etching applications

Murin

Kwon³

2018

IVUZKKT

This work discusses the relationships between the initial composition of the CF4 + C4F8 + Ar gas mixture, gas-phase characteristics and heterogeneous process kinetics under the condition of low-pressure inductively coupled plasma. The goals were to investigate how the CF4/C4F8 mixing ratio influences internal plasma parameters (electron temperature, electron density and ion bombardment energy) and kinetics of plasma active species as well as to analyze how the changes in above parameters may influence the dry etching characteristics, such as etching rates and selectivities. The investigation was carried out using the combination of plasma diagnostics by double Langmuir probes and 0-dimensional plasma modeling. Both experiments and calculations were carried out at constant gas pressure (10 mTorr), input power (800 W) and bias power (150 W) while the CF4/C4F8 mixing ratio was varied through the partial flow rates for corresponding gases. It was shown that the substitution of CF4 for C4F8 in the CF4+C4F8+Ar feed gas lowers F atom formation rates and causes the decreasing F atom flux to the treated surface due to decreasing their volume density. It was proposed that an increase in the densities and fluxes of unsaturated CFx (x=1,2) radicals toward C4F8-rich plasmas at the nearly constant ion energy flux (i.e. at the nearly constant efficiency of ion bombardment) causes a decrease in the effective reaction probability for F atoms through the increasing thickness of the fluorocarbon polymer film on the treated surface.Forcitation:Efremov A.M., Murin D.B., Kwon K.H. Plasma parameters and active species kinetics CF4+C4F8+Ar gas mixture. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N4-5. P. 31-36

Section: Experimental and Modeling Detailsmentioning

confidence: 69%

Section: Experimental and Modeling Detailsmentioning

confidence: 99%

Section: Experimental and Modeling Detailsmentioning

confidence: 99%

Section: Experimental and Modeling Detailsmentioning

confidence: 99%

Section: Experimental and Modeling Detailsmentioning

confidence: 99%

See 3 more Smart Citations

PLASMA PARAMETERS AND ACTIVE SPECIES KINETICS IN CF4+C4F8+Ar GAS MIXTURE

Murin

Kwon³

2018

IVUZKKT

Gas‐phase chemistry and reactive‐ion etching kinetics for silicon‐based materials in C₄F₈ + O₂ + Ar plasma

Lee

Plasma Processes & Polymers

Kwon

2021

Self Cite

In this study, we investigated the effects of C4F8/O2 and Ar/O2 component ratios in C4F8 + O2 + Ar gas system on plasma parameters, gas‐phase chemistry, and etching kinetics for Si, SiO2, and Si3N4 under the condition of inductively coupled radiofrequency (13.56 MHz) plasma. The use of plasma diagnostics by Langmuir probes, together with the zero‐dimensional plasma modeling, allowed one to compare two different gas mixing regimes in respect to (a) electrons‐ and ions‐related plasma parameters; (b) steady‐state densities of plasma active species; and (c) formation and decay kinetics for F atoms and polymerizing radicals. It was shown that variations in both C4F8/O2 and Ar/O2 mixing ratios result in nonmonotonic (with maximums at ∼10% to 15% O2) Si, SiO2, and Si3N4 etching rates as well as in opposite changes in corresponding effective reaction probabilities. The model‐based analysis of etching mechanisms allowed one to suggest that the net effect from all heterogeneous (i.e., appeared on the etched surface) interaction pathways may be controlled either by the fluorocarbon radical flux (in the case of Ar/O2 mixing ratios at constant fraction of C4F8) through the polymer film thickness or by the O atom flux (in the case of C4F8/O2 mixing ratios at constant fraction of Ar) through the balance of adsorption sites.

Comparative study of CF₄ + O₂ and C₆F₁₂O + O₂ plasmas for reactive‐ion etching applications

Lim

Plasma Processes & Polymers

Woo

et al. 2021

Self Cite

This work represents a comparative study of gas-phase parameters and reactive-ion etching kinetics for Si and Si and SiO 2 in CF 4 + O 2 and C 6 F 12 O + O 2 plasmas. An interest to the C 6 F 12 O gas is because it combines the low global warming potential (low environmental impact) and weakly studied dry etching performance. It was shown that the investigated gas systems showed similar effects of processing conditions on electron-and ion-related plasma parameters as well as on the densities of F and O atoms. Etching experiments showed identical behaviors of Si and SiO 2 etching rates as well as very similar SiO 2 /Si etching selectivities. The notable feature of the C 6 F 12 O + O 2 plasma is only the systematically lower absolute etching rates that correlate with lower in F atom densities.dodecafluorooxepane, global warming potential, heterogeneous reaction kinetics, ion energy and flux, plasma diagnostics, plasma modeling | INTRODUCTIONGases from the fluorocarbon family have an important place in the electronic device production industry, as they are used for dry (reactive-ion) patterning of Si and SiO 2 . [1][2][3] These two materials are widely used in planar integrated structures as either substrates (mostly silicon itself) or various functional layers (mostly silicon dioxide). [2][3][4][5] Recently, the increasing attention paid to both device dimensions and performance has led to the continuous optimization of dry etching techniques toward achieving more anisotropic etching profiles, lower surface damage and residues, and better SiO 2 /Si etching selectivities. Progress in this direction requires a thorough understanding of etching mechanisms, transparent interconnections between gas-phase plasma parameters and surface reaction kinetics, and known features of various fluorocarbon-based plasmas in respect to Si and SiO 2 etching processes.