Plasma parameters and active species kinetics in CF4/O2/Ar gas mixture: effects of CF4/O2 and O2/Ar mixing ratios

2016 ◽  
Author(s):  
Junmyung Lee ◽  
Kwang-Ho Kwon ◽  
A. Efremov
Keyword(s):  
Active Species ◽  
Gas Mixture ◽  
Plasma Parameters ◽  
Mixing Ratios ◽  
Mixture Effects ◽  
Ar Gas

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

2018 ◽  
Vol 61 (4-5) ◽  
pp. 31
Author(s):  
Alexander M. Efremov ◽  
Dmitriy B. Murin ◽  
Kwang H. Kwon
Keyword(s):  
Inductively Coupled Plasma ◽  
Ion Bombardment ◽  
Volume Density ◽  
Input Power ◽  
Active Species ◽  
Gas Mixture ◽  
Mixing Ratio ◽  
Plasma Parameters ◽  
Bias Power ◽  
Ar Gas

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

scholarly journals PLASMA PARAMETERS, DENSITIES OF ACTIVE SPECIES AND ETCHING KINETICS IN C4F8+Ar GAS MIXTURE

2019 ◽  
Vol 62 (2) ◽  
pp. 31-37
Author(s):  
Alexander M. Efremov ◽  
Dmitry B. Murin ◽  
Kwang H. Kwon
Keyword(s):  
Steady State ◽  
Plasma Chemistry ◽  
Input Power ◽  
Active Species ◽  
Gas Mixture ◽  
Plasma Parameters ◽  
Experimental Conditions ◽  
Bias Power ◽  
Positive Ions ◽  
Ar Gas

In this work, we performed the combined (experimental and model-based) study of gas-phase plasma characteristics and etching kinetics for both Si and SiO2 in the C4F8 + Ar gas mixture. The experiments were carried out at constant total gas pressure (p = 6 mTorr), input power (W = 900 W) and bias power (Wdc = 200 W) while the C4F8/Ar mixing ratio was varied in the range of 0–75% Ar. The data on internal plasma parameters, plasma chemistry as well as the steady-state plasma composition were obtained by both Langmuir probe diagnostics and 0-dimensional plasma modeling. The etching mechanisms were investigated through the analysis of relationships between the measured etching rates and the model-predicted fluxes of active species (F atoms, polymerizing CFx radicals and positive ions). It was found that, under the given set of experimental conditions, the Si and SiO2 etching process 1) appears in the steady-state etching regime; 2) exhibits the features of the ion-assisted chemical reactions in the neutral-flux-limited mode; and 3) is influenced by the fluorocarbon polymer film thickness. It was shown that the influence of input process parameters on the effective probability of chemical reaction between Si, SiO2 and fluorine atoms may be adequately characterized by the fluorocarbon radicals/fluorine atoms and fluorocarbon radicals/ion energy flux ratios.

PLASMA PARAMETERS, DENSITIES OF ACTIVE SPECIES AND ETCHING KINETICS IN C4F8+Ar GAS MIXTURE

1970 ◽  
Author(s):  
Alexander M. Efremov ◽  
Dmitry B. Murin ◽  
Kwang H. Kwon
Keyword(s):  
Steady State ◽  
Plasma Chemistry ◽  
Input Power ◽  
Active Species ◽  
Gas Mixture ◽  
Plasma Parameters ◽  
Experimental Conditions ◽  
Bias Power ◽  
Positive Ions ◽  
Ar Gas

In this work, we performed the combined (experimental and model-based) study of gas-phase plasma characteristics and etching kinetics for both Si and SiO2 in the C4F8 + Ar gas mixture. The experiments were carried out at constant total gas pressure (p = 6 mTorr), input power (W = 900 W) and bias power (Wdc = 200 W) while the C4F8/Ar mixing ratio was varied in the range of 0–75% Ar. The data on internal plasma parameters, plasma chemistry as well as the steady-state plasma composition were obtained by both Langmuir probe diagnostics and 0-dimensional plasma modeling. The etching mechanisms were investigated through the analysis of relationships between the measured etching rates and the model-predicted fluxes of active species (F atoms, polymerizing CFx radicals and positive ions). It was found that, under the given set of experimental conditions, the Si and SiO2 etching process 1) appears in the steady-state etching regime; 2) exhibits the features of the ion-assisted chemical reactions in the neutral-flux-limited mode; and 3) is influenced by the fluorocarbon polymer film thickness. It was shown that the influence of input process parameters on the effective probability of chemical reaction between Si, SiO2 and fluorine atoms may be adequately characterized by the fluorocarbon radicals/fluorine atoms and fluorocarbon radicals/ion energy flux ratios.

scholarly journals PLASMA PARAMETERS AND COMPOSITION IN CF4/O2/Ar GAS MIXTURE

2017 ◽  
Vol 60 (1) ◽  
pp. 50
Author(s):  
Alexandr M. Efremov ◽  
Kwang-Ho Kwon
Keyword(s):  
Plasma Diagnostics ◽  
Active Species ◽  
Gas Mixture ◽  
Mixing Ratio ◽  
Plasma Modeling ◽  
Langmuir Probes ◽  
Plasma Parameters ◽  
Atom Density ◽  
Gas System ◽  
Ar Gas

For citation:Efremov A.M., Kwon K.-H. Plasma parameters and composition in CF4/O2/Ar gas mixture. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 1. P. 50-55.The effects of O2/Ar mixing ratio in CF4/O2/Ar mixture on both plasma parameters and fluxes of active species determining the dry etching kinetics in this gas system were analyzed. The investigation combined plasma diagnostics by Langmuir probes and zero-dimensional plasma modeling. It was found that the substitution of Ar with O2 at constant fraction of CF4 in a feed gas does not result in the non-monotonic change in F atom density, as it was repeatedly reported for the binary CF4/O2 gas mixtures. The mechanisms of this phenomenon as well as its possible impact on the etching/polymerization kinetics were discussed in details.

scholarly journals PLASMA PARAMETERS AND KINETICS OF ACTIVE SPECIES IN HBr + Cl2 + O2 GAS MIXTURE

2019 ◽  
Vol 62 (7) ◽  
pp. 72-79
Author(s):  
Aleksandr M. Efremov ◽  
Vladimir B. Betelin ◽  
Kwang-Ho Kwon ◽  
Dmitriy G. Snegirev
Keyword(s):  
Variable Parameter ◽  
Plasma Chemistry ◽  
Input Power ◽  
Active Species ◽  
Gas Mixture ◽  
Mixing Ratio ◽  
Plasma Parameters ◽  
Experimental Conditions ◽  
Bias Power ◽  
Atom Density

In this work, we performed the combined (experimental and model-based) study of gas-phase plasma characteristics for HBr + Cl2 + O2 gas mixture under conditions of low-pressure inductive 13.56 MHz discharge. The data on internal plasma parameters, plasma chemistry as well as the steady-state plasma composition were obtained using a combination of Langmuir probe diagnostics and 0-dimensional (global) plasma modeling. Both experimental and modeling procedures were carried out at constant total gas pressure (p = 10 mTorr), input power (W = 500 W), bias power (Wdc = 200 W) and O2 fraction in a feed gas (y(O2) = 11 %). The variable parameter was the HBr + Cl2 mixing ratio, which was changed in the range of 0 – 89 % Cl2. It was found that, under the given set of experimental conditions, the substitution of HBr for Cl2: 1) results in increasing both mean electron energy and electron density; 2) causes the mon-monotonic (with a maximum at ~ 45 % Cl2) change in Br atom density; and 3) provides an increase in O atom density at y(O2) = const. The possible impacts of HBr + Cl2 mixing ratio on Si and SiO2 etching kinetics were estimated through the analysis of model-predicted fluxes for plasma active species (Br, Cl and O atoms, positive ions).

scholarly journals PLASMA PARAMETERS AND SiO2 ETCHING KINETICS IN C4F8 + Ar + O2 GAS MIXTURE

2020 ◽  
Vol 63 (6) ◽  
pp. 37-43
Author(s):  
Alexander M. Efremov ◽  
Vladimir B. Betelin ◽  
Kwang-Ho Kwon
Keyword(s):  
Steady State ◽  
Etching Rate ◽  
Active Species ◽  
Gas Mixture ◽  
Plasma Parameters ◽  
Ion Energy ◽  
State Densities ◽  
Etched Surface ◽  
Fluorocarbon Film ◽  
Sio2 Etching

The effect of Ar/O2 mixing ratio on plasma parameters, steady-state densities of active species and SiO2 etching kinetics in the three-component C4F8+Ar+O2 gas mixture was studied under typical conditions of reactive ion etching process (inductive 13.56 MHz RF discharge, total gas pressure of 6 mTorr, input power of 700 W and bias power of 200 W). The investigation combined etching rate measurements, plasma diagnostics by Langmuir probes and 0-dimensional (global) plasma modeling in order to determine steady-state densities and fluxes of plasma active species. It was found that the full substitution of Ar for O2 at constant fraction of fluorocarbon gas (in fact, the transition from 50% C4F8 + 50% Ar to 50% C4F8 + 50% O2 gas system): 1) results in weakly non-monotonic (with a maximum) SiO2 etching rate with close values for both O2-free and Ar-free plasmas; 2) causes the monotonic decrease in both F atom flux and ion energy flux; and 3) suppresses the formation of the fluorocarbon polymer film on the etched surface through its oxidative destruction pathway. The model-based analysis of SiO2 etching kinetics allowed one to conclude that an increase in effective probability for SiO2 + F reaction contradicts with the behavior ion energy flux as well as demonstrate the agreement with the change in gas-phase parameters characterizing the fluorocarbon film thickness. Therefore, an increase in O2 content in a feed gas influences the effective reaction probability by decreasing fluorocarbon film thickness and providing better access of F atoms to the etched surface.

scholarly journals Dry Etching Performance and Gas-Phase Parameters of C6F12O + Ar Plasma in Comparison with CF4 + Ar

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1595
Author(s):  
Nomin Lim ◽  
Yeon Sik Choi ◽  
Alexander Efremov ◽  
Kwang-Ho Kwon
Keyword(s):  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Reactive Ion Etching ◽  
Research Work ◽  
Optical Emission ◽  
Plasma Parameters ◽  
Ion Etching ◽  
Ar Plasma ◽  
Ar Gas ◽  
Etching Selectivity

This research work deals with the comparative study of C6F12O + Ar and CF4 + Ar gas chemistries in respect to Si and SiO2 reactive-ion etching processes in a low power regime. Despite uncertain applicability of C6F12O as the fluorine-containing etchant gas, it is interesting because of the liquid (at room temperature) nature and weaker environmental impact (lower global warming potential). The combination of several experimental techniques (double Langmuir probe, optical emission spectroscopy, X-ray photoelectron spectroscopy) allowed one (a) to compare performances of given gas systems in respect to the reactive-ion etching of Si and SiO2; and (b) to associate the features of corresponding etching kinetics with those for gas-phase plasma parameters. It was found that both gas systems exhibit (a) similar changes in ion energy flux and F atom flux with variations on input RF power and gas pressure; (b) quite close polymerization abilities; and (c) identical behaviors of Si and SiO2 etching rates, as determined by the neutral-flux-limited regime of ion-assisted chemical reaction. Principal features of C6F12O + Ar plasma are only lower absolute etching rates (mainly due to the lower density and flux of F atoms) as well as some limitations in SiO2/Si etching selectivity.

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