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 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, 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 COMPOSITION IN CF4 + O2 + Ar AND CHF3 + O2 +Ar IN REACTIVE ION ETCHING PROCESSES

2019 ◽  
Vol 62 (12) ◽  
pp. 108-118
Author(s):  
Alexander M. Efremov ◽  
Alexander M. Sobolev ◽  
Vladimir B. Betelin ◽  
Kwang-Ho Kwon
Keyword(s):  
Steady State ◽  
Reactive Ion Etching ◽  
Plasma Chemistry ◽  
Input Power ◽  
Active Species ◽  
Plasma Parameters ◽  
Ion Etching ◽  
Bias Power ◽  
State Densities ◽  
Silicon Based

The comparative analysis of both CF4+O2+Ar and CHF3+O2+Ar plasma systems under the typical conditions of reactive ion etching of silicon and silicon-based compounds was carried out. The data on internal plasma parameters, plasma chemistry as well as the steady-state plasma composition were obtained using a description of Langmuir probe diagnostics and 0-dimensional (global) plasma modeling. As a presented in the literature, both experimental and modeling procedures were carried out at constant total gas pressure, input power, bias power. The obtained results allowed one 1) to figure out the influence of oxygen on steady-state densities of plasma active species through the kinetics of both electron-impact and atom-molecular reactions; 2) to understand the features of fluorine atoms and fluorocarbon radicals kinetics which determine chemical activity and  polymerization ability of  plasmas in respect to treated surfaces; 3) to perform the model-bases analysis of  heterogeneous process kinetics (etching, polymerization, polymer destruction) which determine the overall etching regime and output parameters. It was found that the substitution of argon for oxygen in both gas mixtures 1) results in monotonic increase in fluorine atom density; 2) is accompanied by decreasing polymerization ability of a gas phase and 3) causes the rapid (by about two orders of magnitude at ~ 20% О2) decrease in fluorocarbon polymer film thickness with the higher values for CHF3+O2+Ar system.

scholarly journals FEATURES OF SiO2 REACTIVE-ION ETCHING KINETICS IN CF4 + Ar + O2 AND C4F8 + Ar + O2 GAS MIXTURES

2020 ◽  
Vol 63 (9) ◽  
pp. 21-27
Author(s):  
Alexander M. Efremov ◽  
Alexander M. Sobolev
Keyword(s):  
Gas Phase ◽  
Etching Rate ◽  
Processing Parameters ◽  
Input Power ◽  
Active Species ◽  
Rf Discharge ◽  
Mixing Ratio ◽  
Langmuir Probes ◽  
Bias Power ◽  
Sio2 Etching

The effect of Ar/O2 mixing ratio on gas-phase characteristics and SiO2 etching kinetics in CF4 + Ar + O2 and C4F8 + Ar + O2 plasmas was studied under conditions of 13.56 MHz inductive RF discharge. The constant processing parameters were fraction of fluorocarbon component in a feed gas (50%) total gas pressure (6 mTorr), input power (700 W) and bias power (200 W). It was found that the full substitution of Ar for O2 in both gas systems results in non-monotonic (with a maximum at ~ 25% Ar + 25% O2) SiO2 etching rates as well as in monotonically increasing photoresist etching rate with higher absolute values for CF4-containing mixture. The steady-state densities of active species were determined using a combination of plasma diagnostics by Langmuir probes and 0-dimensional (global) plasma modeling. Corresponding results indicated that both gas systems are characterized by quite close parameters of electron and ion components while exhibit sufficient differences in the kinetics of neutral species, especially in the presence of O2. The latter produces opposite changes in F atom density as well as in effective probability of ion-assisted chemical reaction vs. Ar/O2 mixing ratio. Relationships between type of fluorocarbon component and heterogeneous process kinetics were analyzed through the set of gas-phase-related parameters (fluxes, flux-to-flux ratios) characterizing chemical etching pathways for SiO2 and formation/destruction balance for the fluorocarbon polymer film. It was suggested that the transition toward O2-rich plasma in the low-polymerizing CF4 + Ar + O2 plasma suppresses the effective probability for SiO2 + F reaction through decreasing efficiency for oxide bond breaking and desorption of etching products due to decreasing ion energy flux. Oppositely, an increase in O2 content in the high-polymerizing C4F8 + Ar + O2 mixture lifts up the effective reaction probability by decreasing fluorocarbon film thickness and providing better access of F atoms to the etched surface.

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